<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2023 Workiva-->
<!--r:da0c9023-c274-4f3b-973d-9bcf1567b942,g:565952d3-2b79-43e4-aee7-270bf6f2b840-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://vcel.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY" xlink:type="simple" xlink:href="vcel-20230930.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY"/>
  <link:definitionLink xlink:role="http://vcel.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_a3bc0547-6fe6-4110-b687-bebe4343ac06" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_a3bc0547-6fe6-4110-b687-bebe4343ac06" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_6166cdb3-cfeb-4cfa-b699-be2a2e67ab76" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_6166cdb3-cfeb-4cfa-b699-be2a2e67ab76" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_3f918092-916a-47b3-bace-e452ec6e5a8b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:to="loc_us-gaap_StockholdersEquity_3f918092-916a-47b3-bace-e452ec6e5a8b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_54c5d2f4-e0c5-4e71-b6a2-c815d4f028f6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:to="loc_us-gaap_NetIncomeLoss_54c5d2f4-e0c5-4e71-b6a2-c815d4f028f6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_55a03402-aaa2-438d-9db6-95b10d1f8ff4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_55a03402-aaa2-438d-9db6-95b10d1f8ff4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_70974d20-b14d-436b-8e8f-fcf064399368" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_70974d20-b14d-436b-8e8f-fcf064399368" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_584ec8ad-0ba5-4d32-86b6-05ddf0e51f5d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_584ec8ad-0ba5-4d32-86b6-05ddf0e51f5d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_d1b64920-4727-4e78-9717-fa07a9ce9c75" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_d1b64920-4727-4e78-9717-fa07a9ce9c75" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_9f7a36d6-45a6-43a0-9da7-bb9d4801e448" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_9f7a36d6-45a6-43a0-9da7-bb9d4801e448" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_f27dcba3-6d8a-49da-85d8-6c286fb30cda" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_f27dcba3-6d8a-49da-85d8-6c286fb30cda" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_84e3274f-d82b-43cf-8269-c0996df37fe3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_84e3274f-d82b-43cf-8269-c0996df37fe3" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_84980782-d41a-4b02-8102-5656e666dfca" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_84980782-d41a-4b02-8102-5656e666dfca" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_0a3e1e8d-7159-4d73-88ab-8afd956a91aa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a22036bb-c4ee-43d6-8090-2f0519e0ccbd" xlink:to="loc_us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_0a3e1e8d-7159-4d73-88ab-8afd956a91aa" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_16b30285-51df-4f2b-ad27-7014aa098dc0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_9a6debc1-0ec7-4d71-ae67-3eef219d35aa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_b0f6f159-8c88-4da5-9361-87dddb920dcf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_a3bc0547-6fe6-4110-b687-bebe4343ac06" xlink:to="loc_us-gaap_StatementTable_b0f6f159-8c88-4da5-9361-87dddb920dcf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_a1d93725-779e-4967-84b9-f194787af886" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b0f6f159-8c88-4da5-9361-87dddb920dcf" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_a1d93725-779e-4967-84b9-f194787af886" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_a1d93725-779e-4967-84b9-f194787af886_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_a1d93725-779e-4967-84b9-f194787af886" xlink:to="loc_us-gaap_EquityComponentDomain_a1d93725-779e-4967-84b9-f194787af886_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_d470a3f8-c6d0-4e2a-973e-f7c4730b4a59" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_a1d93725-779e-4967-84b9-f194787af886" xlink:to="loc_us-gaap_EquityComponentDomain_d470a3f8-c6d0-4e2a-973e-f7c4730b4a59" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_fc5a5fce-c416-4c1a-8f88-8dd345b29427" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_d470a3f8-c6d0-4e2a-973e-f7c4730b4a59" xlink:to="loc_us-gaap_CommonStockMember_fc5a5fce-c416-4c1a-8f88-8dd345b29427" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_e116b327-3905-485d-b6c2-3e6a48ebfa40" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_d470a3f8-c6d0-4e2a-973e-f7c4730b4a59" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_e116b327-3905-485d-b6c2-3e6a48ebfa40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_84b2e177-e6a9-49b3-8c97-b3b5839316e3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_d470a3f8-c6d0-4e2a-973e-f7c4730b4a59" xlink:to="loc_us-gaap_RetainedEarningsMember_84b2e177-e6a9-49b3-8c97-b3b5839316e3" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/RevenueNarrativeDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#RevenueNarrativeDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/RevenueNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_dc2d2daa-0bb7-42e8-ad05-9d163c6f10a3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_NumberOfContractedSpecialtyPharmacies_f42a14aa-5b14-4411-93e1-4e36a2e7d57e" xlink:href="vcel-20230930.xsd#vcel_NumberOfContractedSpecialtyPharmacies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_dc2d2daa-0bb7-42e8-ad05-9d163c6f10a3" xlink:to="loc_vcel_NumberOfContractedSpecialtyPharmacies_f42a14aa-5b14-4411-93e1-4e36a2e7d57e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulOtherReceivablesCurrent_6e490e42-cdce-4a2a-ada1-c7bc5d4d737c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AllowanceForDoubtfulOtherReceivablesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_dc2d2daa-0bb7-42e8-ad05-9d163c6f10a3" xlink:to="loc_us-gaap_AllowanceForDoubtfulOtherReceivablesCurrent_6e490e42-cdce-4a2a-ada1-c7bc5d4d737c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_RevenueRevenueRecognizedChangeinUncollectibleAnalysisPercentage_3670cb4f-898d-4c69-b400-40d5df5db798" xlink:href="vcel-20230930.xsd#vcel_RevenueRevenueRecognizedChangeinUncollectibleAnalysisPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_dc2d2daa-0bb7-42e8-ad05-9d163c6f10a3" xlink:to="loc_vcel_RevenueRevenueRecognizedChangeinUncollectibleAnalysisPercentage_3670cb4f-898d-4c69-b400-40d5df5db798" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_RevenueRevenueRecognizedEffectOf0.5ChangeInTheEstimatedUncollectiblePercentageAmount_45866c38-5403-4bb4-a4f0-1821bcb41639" xlink:href="vcel-20230930.xsd#vcel_RevenueRevenueRecognizedEffectOf0.5ChangeInTheEstimatedUncollectiblePercentageAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_dc2d2daa-0bb7-42e8-ad05-9d163c6f10a3" xlink:to="loc_vcel_RevenueRevenueRecognizedEffectOf0.5ChangeInTheEstimatedUncollectiblePercentageAmount_45866c38-5403-4bb4-a4f0-1821bcb41639" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LicenseAgreementAdditionalFunding_23acc0d0-c678-4e30-95ce-e9de004d73fe" xlink:href="vcel-20230930.xsd#vcel_LicenseAgreementAdditionalFunding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_dc2d2daa-0bb7-42e8-ad05-9d163c6f10a3" xlink:to="loc_vcel_LicenseAgreementAdditionalFunding_23acc0d0-c678-4e30-95ce-e9de004d73fe" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_6cb43151-87d2-481e-be7c-e37603fcca20" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_dc2d2daa-0bb7-42e8-ad05-9d163c6f10a3" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_6cb43151-87d2-481e-be7c-e37603fcca20" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_2e2c58bb-d5a5-4260-b0a2-bca172f9a1e5" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_6cb43151-87d2-481e-be7c-e37603fcca20" xlink:to="loc_srt_CounterpartyNameAxis_2e2c58bb-d5a5-4260-b0a2-bca172f9a1e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_2e2c58bb-d5a5-4260-b0a2-bca172f9a1e5_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_2e2c58bb-d5a5-4260-b0a2-bca172f9a1e5" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_2e2c58bb-d5a5-4260-b0a2-bca172f9a1e5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_f73c278b-aee3-46bc-b211-bd87ebb847b0" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_2e2c58bb-d5a5-4260-b0a2-bca172f9a1e5" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_f73c278b-aee3-46bc-b211-bd87ebb847b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_MediWoundLtdMember_f3a0bfd6-95d6-43f5-b920-31cb6c67fb42" xlink:href="vcel-20230930.xsd#vcel_MediWoundLtdMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_f73c278b-aee3-46bc-b211-bd87ebb847b0" xlink:to="loc_vcel_MediWoundLtdMember_f3a0bfd6-95d6-43f5-b920-31cb6c67fb42" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/RevenueSummaryofDisaggregationofRevenueDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#RevenueSummaryofDisaggregationofRevenueDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/RevenueSummaryofDisaggregationofRevenueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_5f560663-42ba-4b5b-a3be-54489bdca670" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_2813d9f5-43a3-446e-8a05-264bd9bfa212" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_5f560663-42ba-4b5b-a3be-54489bdca670" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_2813d9f5-43a3-446e-8a05-264bd9bfa212" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueNotFromContractWithCustomerOther_ad2683c8-deb7-4124-bc97-033d7fd7afe0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueNotFromContractWithCustomerOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_5f560663-42ba-4b5b-a3be-54489bdca670" xlink:to="loc_us-gaap_RevenueNotFromContractWithCustomerOther_ad2683c8-deb7-4124-bc97-033d7fd7afe0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_1da9e029-722a-457a-90ea-8b41ad76a6a2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_5f560663-42ba-4b5b-a3be-54489bdca670" xlink:to="loc_us-gaap_Revenues_1da9e029-722a-457a-90ea-8b41ad76a6a2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_dd3a0102-97f8-4e4d-aafb-783c33bdebc2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_5f560663-42ba-4b5b-a3be-54489bdca670" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_dd3a0102-97f8-4e4d-aafb-783c33bdebc2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_379b4021-47b3-496e-80d5-88376bb47ad2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerSalesChannelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_dd3a0102-97f8-4e4d-aafb-783c33bdebc2" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_379b4021-47b3-496e-80d5-88376bb47ad2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_379b4021-47b3-496e-80d5-88376bb47ad2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_379b4021-47b3-496e-80d5-88376bb47ad2" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_379b4021-47b3-496e-80d5-88376bb47ad2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_45e22346-bde5-4f02-8eba-5e19bff1406c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_379b4021-47b3-496e-80d5-88376bb47ad2" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_45e22346-bde5-4f02-8eba-5e19bff1406c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelThroughIntermediaryMember_279a652c-21a1-48ad-9ecf-9a952a7fe7c8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SalesChannelThroughIntermediaryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_45e22346-bde5-4f02-8eba-5e19bff1406c" xlink:to="loc_us-gaap_SalesChannelThroughIntermediaryMember_279a652c-21a1-48ad-9ecf-9a952a7fe7c8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimeAndMaterialsContractMember_ed0bc63c-f75f-4f5b-9fd6-436d889031d8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimeAndMaterialsContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_45e22346-bde5-4f02-8eba-5e19bff1406c" xlink:to="loc_us-gaap_TimeAndMaterialsContractMember_ed0bc63c-f75f-4f5b-9fd6-436d889031d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_ProviderorFacilityMember_ab1eff69-fc81-44f0-99bc-eebbc507b9c7" xlink:href="vcel-20230930.xsd#vcel_ProviderorFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_45e22346-bde5-4f02-8eba-5e19bff1406c" xlink:to="loc_vcel_ProviderorFacilityMember_ab1eff69-fc81-44f0-99bc-eebbc507b9c7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_d58dc662-fd9e-49e1-9297-eb2448eed54e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SalesChannelDirectlyToConsumerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_45e22346-bde5-4f02-8eba-5e19bff1406c" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_d58dc662-fd9e-49e1-9297-eb2448eed54e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_c7e50d2f-e916-4372-98db-ed0fb82875e5" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_dd3a0102-97f8-4e4d-aafb-783c33bdebc2" xlink:to="loc_srt_ProductOrServiceAxis_c7e50d2f-e916-4372-98db-ed0fb82875e5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_c7e50d2f-e916-4372-98db-ed0fb82875e5_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_c7e50d2f-e916-4372-98db-ed0fb82875e5" xlink:to="loc_srt_ProductsAndServicesDomain_c7e50d2f-e916-4372-98db-ed0fb82875e5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_50a983f6-9e4b-49dd-a3b3-966f1f301304" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_c7e50d2f-e916-4372-98db-ed0fb82875e5" xlink:to="loc_srt_ProductsAndServicesDomain_50a983f6-9e4b-49dd-a3b3-966f1f301304" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_ImplantsMember_70b250cd-cdd3-49c0-903a-697bdba528f0" xlink:href="vcel-20230930.xsd#vcel_ImplantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_50a983f6-9e4b-49dd-a3b3-966f1f301304" xlink:to="loc_vcel_ImplantsMember_70b250cd-cdd3-49c0-903a-697bdba528f0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_BiopsyKitsMember_b46dd7fc-53f2-4ff1-b790-91d3e52050b9" xlink:href="vcel-20230930.xsd#vcel_BiopsyKitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_50a983f6-9e4b-49dd-a3b3-966f1f301304" xlink:to="loc_vcel_BiopsyKitsMember_b46dd7fc-53f2-4ff1-b790-91d3e52050b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_MACIImplantsAndKitsMember_e313eb97-d39f-4598-9230-f072eb818ae5" xlink:href="vcel-20230930.xsd#vcel_MACIImplantsAndKitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_50a983f6-9e4b-49dd-a3b3-966f1f301304" xlink:to="loc_vcel_MACIImplantsAndKitsMember_e313eb97-d39f-4598-9230-f072eb818ae5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_EpicelMember_66895b82-884b-466e-aca5-fe6984210fbb" xlink:href="vcel-20230930.xsd#vcel_EpicelMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_50a983f6-9e4b-49dd-a3b3-966f1f301304" xlink:to="loc_vcel_EpicelMember_66895b82-884b-466e-aca5-fe6984210fbb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_NexoBridMember_a16a968e-0aa1-4d22-b59c-13455fdb2fc7" xlink:href="vcel-20230930.xsd#vcel_NexoBridMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_50a983f6-9e4b-49dd-a3b3-966f1f301304" xlink:to="loc_vcel_NexoBridMember_a16a968e-0aa1-4d22-b59c-13455fdb2fc7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_d67f70b6-a14c-4f94-b278-5cef8ec31a4e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerBasisOfPricingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_dd3a0102-97f8-4e4d-aafb-783c33bdebc2" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_d67f70b6-a14c-4f94-b278-5cef8ec31a4e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_d67f70b6-a14c-4f94-b278-5cef8ec31a4e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerBasisOfPricingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_d67f70b6-a14c-4f94-b278-5cef8ec31a4e" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_d67f70b6-a14c-4f94-b278-5cef8ec31a4e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_341ee8d9-888f-4a19-8543-0dc51198e98e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerBasisOfPricingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_d67f70b6-a14c-4f94-b278-5cef8ec31a4e" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_341ee8d9-888f-4a19-8543-0dc51198e98e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedPriceContractMember_3e7ff287-bd29-4d5a-a8a9-e196fb7d11b0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FixedPriceContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_341ee8d9-888f-4a19-8543-0dc51198e98e" xlink:to="loc_us-gaap_FixedPriceContractMember_3e7ff287-bd29-4d5a-a8a9-e196fb7d11b0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimeAndMaterialsContractMember_139d616d-c631-4364-8de8-a34ba0f841f9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimeAndMaterialsContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_341ee8d9-888f-4a19-8543-0dc51198e98e" xlink:to="loc_us-gaap_TimeAndMaterialsContractMember_139d616d-c631-4364-8de8-a34ba0f841f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_2959235d-d14b-42aa-b0bf-8a624204db2d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_dd3a0102-97f8-4e4d-aafb-783c33bdebc2" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_2959235d-d14b-42aa-b0bf-8a624204db2d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_2959235d-d14b-42aa-b0bf-8a624204db2d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_2959235d-d14b-42aa-b0bf-8a624204db2d" xlink:to="loc_us-gaap_TypeOfAdoptionMember_2959235d-d14b-42aa-b0bf-8a624204db2d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_02fb3ef0-78f3-468c-84d2-5ab172dddb4e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_2959235d-d14b-42aa-b0bf-8a624204db2d" xlink:to="loc_us-gaap_TypeOfAdoptionMember_02fb3ef0-78f3-468c-84d2-5ab172dddb4e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate201409Member_a85f8f7d-fa33-45b4-8708-bf36a763ef63" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountingStandardsUpdate201409Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_02fb3ef0-78f3-468c-84d2-5ab172dddb4e" xlink:to="loc_us-gaap_AccountingStandardsUpdate201409Member_a85f8f7d-fa33-45b4-8708-bf36a763ef63" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInAccountingEstimateByTypeAxis_780f78c5-af9d-452b-a1b6-1184ed99b904" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ChangeInAccountingEstimateByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_dd3a0102-97f8-4e4d-aafb-783c33bdebc2" xlink:to="loc_us-gaap_ChangeInAccountingEstimateByTypeAxis_780f78c5-af9d-452b-a1b6-1184ed99b904" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_780f78c5-af9d-452b-a1b6-1184ed99b904_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ChangeInAccountingEstimateTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ChangeInAccountingEstimateByTypeAxis_780f78c5-af9d-452b-a1b6-1184ed99b904" xlink:to="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_780f78c5-af9d-452b-a1b6-1184ed99b904_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_9fd1eccd-c781-4362-a0cd-dea2bc8a7aa6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ChangeInAccountingEstimateTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ChangeInAccountingEstimateByTypeAxis_780f78c5-af9d-452b-a1b6-1184ed99b904" xlink:to="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_9fd1eccd-c781-4362-a0cd-dea2bc8a7aa6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInAccountingMethodAccountedForAsChangeInEstimateMember_db92673a-b6b8-48e9-a331-d9fe6f7b2b8b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ChangeInAccountingMethodAccountedForAsChangeInEstimateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_9fd1eccd-c781-4362-a0cd-dea2bc8a7aa6" xlink:to="loc_us-gaap_ChangeInAccountingMethodAccountedForAsChangeInEstimateMember_db92673a-b6b8-48e9-a331-d9fe6f7b2b8b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/SelectedBalanceSheetComponentsScheduleofpropertyandequipmentnetDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#SelectedBalanceSheetComponentsScheduleofpropertyandequipmentnetDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/SelectedBalanceSheetComponentsScheduleofpropertyandequipmentnetDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_fbbfd0f8-c792-4c42-ab22-372b5ade8d9e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_47a405c3-a7ee-4979-ac6a-7c97b4065658" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_fbbfd0f8-c792-4c42-ab22-372b5ade8d9e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_47a405c3-a7ee-4979-ac6a-7c97b4065658" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization_caaac50f-9574-4882-b456-28cc3cdfe088" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_fbbfd0f8-c792-4c42-ab22-372b5ade8d9e" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization_caaac50f-9574-4882-b456-28cc3cdfe088" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_2082231d-4696-4f1f-bf1b-d47628440bf4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_fbbfd0f8-c792-4c42-ab22-372b5ade8d9e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_2082231d-4696-4f1f-bf1b-d47628440bf4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_899144d9-c7dd-4b96-a9fa-faca21c95603" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_fbbfd0f8-c792-4c42-ab22-372b5ade8d9e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_899144d9-c7dd-4b96-a9fa-faca21c95603" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_9279bc9f-ed04-4f76-a105-d35d01d0f377" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_fbbfd0f8-c792-4c42-ab22-372b5ade8d9e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_9279bc9f-ed04-4f76-a105-d35d01d0f377" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_0ff9e971-5016-4e20-9fc4-29e6ff5f4dcf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_fbbfd0f8-c792-4c42-ab22-372b5ade8d9e" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_0ff9e971-5016-4e20-9fc4-29e6ff5f4dcf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_03eb0b72-1049-42a7-b849-f1c5ae74e4d3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_0ff9e971-5016-4e20-9fc4-29e6ff5f4dcf" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_03eb0b72-1049-42a7-b849-f1c5ae74e4d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_03eb0b72-1049-42a7-b849-f1c5ae74e4d3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_03eb0b72-1049-42a7-b849-f1c5ae74e4d3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_03eb0b72-1049-42a7-b849-f1c5ae74e4d3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8ed90352-48bc-4ae6-86fe-045cdade3a9e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_03eb0b72-1049-42a7-b849-f1c5ae74e4d3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8ed90352-48bc-4ae6-86fe-045cdade3a9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MachineryAndEquipmentMember_8bf4ef69-13b9-45d0-b2db-ef8a575f064f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MachineryAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8ed90352-48bc-4ae6-86fe-045cdade3a9e" xlink:to="loc_us-gaap_MachineryAndEquipmentMember_8bf4ef69-13b9-45d0-b2db-ef8a575f064f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_81f58335-7321-40d2-9c86-7d0e97cb4fe3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8ed90352-48bc-4ae6-86fe-045cdade3a9e" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_81f58335-7321-40d2-9c86-7d0e97cb4fe3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_ComputerEquipmentAndComputerSoftwareIntangibleAssetMember_44785e5a-be68-49ac-9146-be31d2413c55" xlink:href="vcel-20230930.xsd#vcel_ComputerEquipmentAndComputerSoftwareIntangibleAssetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8ed90352-48bc-4ae6-86fe-045cdade3a9e" xlink:to="loc_vcel_ComputerEquipmentAndComputerSoftwareIntangibleAssetMember_44785e5a-be68-49ac-9146-be31d2413c55" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_18974004-d134-4d3d-994b-a9f5be2a8b9a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8ed90352-48bc-4ae6-86fe-045cdade3a9e" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_18974004-d134-4d3d-994b-a9f5be2a8b9a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_b5f1a46f-74d8-4c69-af51-8b30ee5e3d85" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8ed90352-48bc-4ae6-86fe-045cdade3a9e" xlink:to="loc_us-gaap_ConstructionInProgressMember_b5f1a46f-74d8-4c69-af51-8b30ee5e3d85" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/SelectedBalanceSheetComponentsNarrativeDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#SelectedBalanceSheetComponentsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/SelectedBalanceSheetComponentsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3cbb42b6-954a-4bf9-ab9b-9ef7c653e990" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_758e9a82-5f00-4034-af1f-9f18c54f2693" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3cbb42b6-954a-4bf9-ab9b-9ef7c653e990" xlink:to="loc_us-gaap_Depreciation_758e9a82-5f00-4034-af1f-9f18c54f2693" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_9d3339cc-9900-4122-8a5c-b7af1d370ae4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3cbb42b6-954a-4bf9-ab9b-9ef7c653e990" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_9d3339cc-9900-4122-8a5c-b7af1d370ae4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_7f65ab6c-4c1d-4a4c-8de0-385ab491792c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3cbb42b6-954a-4bf9-ab9b-9ef7c653e990" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_7f65ab6c-4c1d-4a4c-8de0-385ab491792c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_fb7a96bd-0364-4598-a01e-a25fb839fdce" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_7f65ab6c-4c1d-4a4c-8de0-385ab491792c" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_fb7a96bd-0364-4598-a01e-a25fb839fdce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_fb7a96bd-0364-4598-a01e-a25fb839fdce_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_fb7a96bd-0364-4598-a01e-a25fb839fdce" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_fb7a96bd-0364-4598-a01e-a25fb839fdce_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_887eeb35-7a74-4314-8d4d-bdcac4dd1ca6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_fb7a96bd-0364-4598-a01e-a25fb839fdce" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_887eeb35-7a74-4314-8d4d-bdcac4dd1ca6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LicensingAgreementsMember_8171d563-8d2b-41b0-bb85-9784c26b7463" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LicensingAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_887eeb35-7a74-4314-8d4d-bdcac4dd1ca6" xlink:to="loc_us-gaap_LicensingAgreementsMember_8171d563-8d2b-41b0-bb85-9784c26b7463" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/SelectedBalanceSheetComponentsScheduleoffinitelivedintangibleassetsDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#SelectedBalanceSheetComponentsScheduleoffinitelivedintangibleassetsDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/SelectedBalanceSheetComponentsScheduleoffinitelivedintangibleassetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_b913b98d-75ab-47cf-8000-82a21a03cea9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_012845b7-e578-4c6c-97ee-8e418e97f472" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_b913b98d-75ab-47cf-8000-82a21a03cea9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_012845b7-e578-4c6c-97ee-8e418e97f472" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_85e240c7-901b-4774-aa13-e208582053ec" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_b913b98d-75ab-47cf-8000-82a21a03cea9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_85e240c7-901b-4774-aa13-e208582053ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_8e8f6ba1-bfd6-4a33-87db-34f9a3c1fd42" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_b913b98d-75ab-47cf-8000-82a21a03cea9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_8e8f6ba1-bfd6-4a33-87db-34f9a3c1fd42" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_122712e9-6973-4361-a9dc-bd7daf96e5b1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_b913b98d-75ab-47cf-8000-82a21a03cea9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_122712e9-6973-4361-a9dc-bd7daf96e5b1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_3914477a-de45-4a83-951b-8a7ec77d87d2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_b913b98d-75ab-47cf-8000-82a21a03cea9" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_3914477a-de45-4a83-951b-8a7ec77d87d2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_653e215b-ddf2-47b5-8be6-fa0d9a04cd04" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_3914477a-de45-4a83-951b-8a7ec77d87d2" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_653e215b-ddf2-47b5-8be6-fa0d9a04cd04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_653e215b-ddf2-47b5-8be6-fa0d9a04cd04_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_653e215b-ddf2-47b5-8be6-fa0d9a04cd04" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_653e215b-ddf2-47b5-8be6-fa0d9a04cd04_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_167ba5d9-1592-485e-9b8c-48171d5b508b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_653e215b-ddf2-47b5-8be6-fa0d9a04cd04" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_167ba5d9-1592-485e-9b8c-48171d5b508b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LicensingAgreementsMember_0a5f25a8-82e9-43ac-b767-cb8286d33df5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LicensingAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_167ba5d9-1592-485e-9b8c-48171d5b508b" xlink:to="loc_us-gaap_LicensingAgreementsMember_0a5f25a8-82e9-43ac-b767-cb8286d33df5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/SelectedBalanceSheetComponentsScheduleoffinitelivedintangibleassetsfutureamortizationexpenseDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#SelectedBalanceSheetComponentsScheduleoffinitelivedintangibleassetsfutureamortizationexpenseDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/SelectedBalanceSheetComponentsScheduleoffinitelivedintangibleassetsfutureamortizationexpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_aecec128-b62c-4e26-8aa3-0df83820e8c8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_23bb8d60-43c6-4409-9b58-bfe03ba450b8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_aecec128-b62c-4e26-8aa3-0df83820e8c8" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_23bb8d60-43c6-4409-9b58-bfe03ba450b8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_2336bdfa-ce46-46ff-a3f9-c3503d977edf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_aecec128-b62c-4e26-8aa3-0df83820e8c8" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_2336bdfa-ce46-46ff-a3f9-c3503d977edf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_f9a27a45-8912-400b-a986-46e18332e221" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_aecec128-b62c-4e26-8aa3-0df83820e8c8" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_f9a27a45-8912-400b-a986-46e18332e221" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_e16bb87e-decc-450f-bf27-8755b95ac145" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_aecec128-b62c-4e26-8aa3-0df83820e8c8" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_e16bb87e-decc-450f-bf27-8755b95ac145" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_24eb26ea-eccd-4e5a-aa76-2fe80b127b98" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_aecec128-b62c-4e26-8aa3-0df83820e8c8" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_24eb26ea-eccd-4e5a-aa76-2fe80b127b98" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_FiniteLivedIntangibleAssetExpectedAmortizationAfterYearFour_31b32f5f-c187-4f47-b80b-03916fbb5861" xlink:href="vcel-20230930.xsd#vcel_FiniteLivedIntangibleAssetExpectedAmortizationAfterYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_aecec128-b62c-4e26-8aa3-0df83820e8c8" xlink:to="loc_vcel_FiniteLivedIntangibleAssetExpectedAmortizationAfterYearFour_31b32f5f-c187-4f47-b80b-03916fbb5861" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_7294180d-701f-4708-92f5-943c805f3bbd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_aecec128-b62c-4e26-8aa3-0df83820e8c8" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_7294180d-701f-4708-92f5-943c805f3bbd" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_bdfd881e-6d58-428f-8e73-800549a4dff6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_aecec128-b62c-4e26-8aa3-0df83820e8c8" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_bdfd881e-6d58-428f-8e73-800549a4dff6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_d266b873-92c9-46a8-800b-3e433840bc9e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_bdfd881e-6d58-428f-8e73-800549a4dff6" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_d266b873-92c9-46a8-800b-3e433840bc9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d266b873-92c9-46a8-800b-3e433840bc9e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_d266b873-92c9-46a8-800b-3e433840bc9e" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d266b873-92c9-46a8-800b-3e433840bc9e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_abf4c212-5d5c-4334-aacf-54d86d47effb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_d266b873-92c9-46a8-800b-3e433840bc9e" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_abf4c212-5d5c-4334-aacf-54d86d47effb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LicensingAgreementsMember_c42c1cd7-1cb8-450f-ae63-00ed3ea0cc3d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LicensingAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_abf4c212-5d5c-4334-aacf-54d86d47effb" xlink:to="loc_us-gaap_LicensingAgreementsMember_c42c1cd7-1cb8-450f-ae63-00ed3ea0cc3d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/LeasesNarrativeDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#LeasesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/LeasesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LesseeOperatingLeaseMonthlyContractualPayments_b64fbff1-d8f8-4a94-8c4d-57b8aab878b5" xlink:href="vcel-20230930.xsd#vcel_LesseeOperatingLeaseMonthlyContractualPayments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_LesseeOperatingLeaseMonthlyContractualPayments_b64fbff1-d8f8-4a94-8c4d-57b8aab878b5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty_5dab3c00-df49-4f14-8528-0a6dd37b91cf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_us-gaap_AreaOfRealEstateProperty_5dab3c00-df49-4f14-8528-0a6dd37b91cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_EscrowDepositPercentContributed_1688053a-01bf-43a5-83f4-f37113638504" xlink:href="vcel-20230930.xsd#vcel_EscrowDepositPercentContributed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_EscrowDepositPercentContributed_1688053a-01bf-43a5-83f4-f37113638504" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EscrowDeposit_0117d2f1-5394-4e68-aef4-15e270fb8da5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EscrowDeposit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_us-gaap_EscrowDeposit_0117d2f1-5394-4e68-aef4-15e270fb8da5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_EscrowDepositRemainingPercentToBeContributed_6fa81539-0dff-492a-bbcc-ace9ffc5a2cf" xlink:href="vcel-20230930.xsd#vcel_EscrowDepositRemainingPercentToBeContributed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_EscrowDepositRemainingPercentToBeContributed_6fa81539-0dff-492a-bbcc-ace9ffc5a2cf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LesseeLeaseCommencementRentPaymentStartDateTerm_238a87b1-2fca-4afb-9720-a30851ecce8e" xlink:href="vcel-20230930.xsd#vcel_LesseeLeaseCommencementRentPaymentStartDateTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_LesseeLeaseCommencementRentPaymentStartDateTerm_238a87b1-2fca-4afb-9720-a30851ecce8e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseTermOfContract_6db50877-ad4b-44d4-a4d4-421be528663f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeOperatingLeaseTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_us-gaap_LesseeOperatingLeaseTermOfContract_6db50877-ad4b-44d4-a4d4-421be528663f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LesseeOperatingLeaseNumberOfRenewalOptions_920efcd8-ccb8-419d-a16e-e9c000fda781" xlink:href="vcel-20230930.xsd#vcel_LesseeOperatingLeaseNumberOfRenewalOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_LesseeOperatingLeaseNumberOfRenewalOptions_920efcd8-ccb8-419d-a16e-e9c000fda781" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LeaseOptionToExtendTerm_cf1aac6b-f3c7-4c6a-8f46-648ff1d2f305" xlink:href="vcel-20230930.xsd#vcel_LeaseOptionToExtendTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_LeaseOptionToExtendTerm_cf1aac6b-f3c7-4c6a-8f46-648ff1d2f305" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LesseeOperatingLeaseAnnualLeasePerSquareFoot_12e5d67c-3cdc-46e2-907f-6bacbe50c44d" xlink:href="vcel-20230930.xsd#vcel_LesseeOperatingLeaseAnnualLeasePerSquareFoot"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_LesseeOperatingLeaseAnnualLeasePerSquareFoot_12e5d67c-3cdc-46e2-907f-6bacbe50c44d" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LesseeOperatingLeaseAnnualLeaseIncreaseLimitPercentage_dce839d3-a9cc-4e9d-bdb4-34f60678b81a" xlink:href="vcel-20230930.xsd#vcel_LesseeOperatingLeaseAnnualLeaseIncreaseLimitPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_LesseeOperatingLeaseAnnualLeaseIncreaseLimitPercentage_dce839d3-a9cc-4e9d-bdb4-34f60678b81a" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LesseeOperatingLeaseTenantImprovementAllowancePerSquareFoot_088dd523-4690-4bf4-ae38-c9440bba34e3" xlink:href="vcel-20230930.xsd#vcel_LesseeOperatingLeaseTenantImprovementAllowancePerSquareFoot"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_LesseeOperatingLeaseTenantImprovementAllowancePerSquareFoot_088dd523-4690-4bf4-ae38-c9440bba34e3" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LesseeOperatingLeaseTenantImprovementAllowance_689e270f-a93f-4928-b978-458a8dc08295" xlink:href="vcel-20230930.xsd#vcel_LesseeOperatingLeaseTenantImprovementAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_LesseeOperatingLeaseTenantImprovementAllowance_689e270f-a93f-4928-b978-458a8dc08295" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_b359e8d7-4826-4265-8fae-d7778782e7e3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_b359e8d7-4826-4265-8fae-d7778782e7e3" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_8c8811f0-2460-4a15-bea8-eb32f5023e59" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_us-gaap_OperatingLeaseLiability_8c8811f0-2460-4a15-bea8-eb32f5023e59" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_OperatingLeaseLiabilityIncrementalBorrowingRate_1ea692e0-c07b-42a0-8a94-6461f03e32b2" xlink:href="vcel-20230930.xsd#vcel_OperatingLeaseLiabilityIncrementalBorrowingRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_OperatingLeaseLiabilityIncrementalBorrowingRate_1ea692e0-c07b-42a0-8a94-6461f03e32b2" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LesseeOperatingLeaseTermOfContractInclusiveOfFreeRent_c2bbd01c-179f-499b-ad6a-9e27fe09e733" xlink:href="vcel-20230930.xsd#vcel_LesseeOperatingLeaseTermOfContractInclusiveOfFreeRent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_LesseeOperatingLeaseTermOfContractInclusiveOfFreeRent_c2bbd01c-179f-499b-ad6a-9e27fe09e733" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LetterOfCreditCashDeposit_438991bd-a0ae-4ad8-b78c-b46fba0be8de" xlink:href="vcel-20230930.xsd#vcel_LetterOfCreditCashDeposit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_LetterOfCreditCashDeposit_438991bd-a0ae-4ad8-b78c-b46fba0be8de" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LetterOfCreditCashDepositLeaseYearThree_63d730aa-03f0-4bc3-a8be-1faa08ed8ac3" xlink:href="vcel-20230930.xsd#vcel_LetterOfCreditCashDepositLeaseYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_LetterOfCreditCashDepositLeaseYearThree_63d730aa-03f0-4bc3-a8be-1faa08ed8ac3" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LetterOfCreditCashDepositLeaseYearFour_d7365a28-189e-4a9e-91d7-a6bcf49519ed" xlink:href="vcel-20230930.xsd#vcel_LetterOfCreditCashDepositLeaseYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_vcel_LetterOfCreditCashDepositLeaseYearFour_d7365a28-189e-4a9e-91d7-a6bcf49519ed" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermLeaseCost_db8282c6-829c-4782-8d72-e464cb919375" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermLeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_us-gaap_ShortTermLeaseCost_db8282c6-829c-4782-8d72-e464cb919375" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseExpense_0389ee89-e4ef-4842-a88b-a7a9643f1742" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_us-gaap_OperatingLeaseExpense_0389ee89-e4ef-4842-a88b-a7a9643f1742" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseInterestExpense_387f31a4-6add-44bf-bc48-693d9dfd4d57" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseInterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_us-gaap_FinanceLeaseInterestExpense_387f31a4-6add-44bf-bc48-693d9dfd4d57" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_240be0e3-79b6-43fc-a6fe-dfc1d007be61" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ce026ab3-68c3-46fa-b8f6-d611614526ff" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_240be0e3-79b6-43fc-a6fe-dfc1d007be61" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_901990b4-94de-42d3-91b4-494636085968" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_240be0e3-79b6-43fc-a6fe-dfc1d007be61" xlink:to="loc_srt_RangeAxis_901990b4-94de-42d3-91b4-494636085968" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_901990b4-94de-42d3-91b4-494636085968_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_901990b4-94de-42d3-91b4-494636085968" xlink:to="loc_srt_RangeMember_901990b4-94de-42d3-91b4-494636085968_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_0d15fd6b-4df6-4f4a-9e17-d3f7fd52040d" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_901990b4-94de-42d3-91b4-494636085968" xlink:to="loc_srt_RangeMember_0d15fd6b-4df6-4f4a-9e17-d3f7fd52040d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_0c95739d-3e5b-4a97-a58e-d6ab29240edb" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_0d15fd6b-4df6-4f4a-9e17-d3f7fd52040d" xlink:to="loc_srt_MinimumMember_0c95739d-3e5b-4a97-a58e-d6ab29240edb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_06f99658-0cf1-4b63-8aaa-624855ec9ee8" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_0d15fd6b-4df6-4f4a-9e17-d3f7fd52040d" xlink:to="loc_srt_MaximumMember_06f99658-0cf1-4b63-8aaa-624855ec9ee8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_1e74eac1-c96a-4123-99be-11431883ab7a" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_240be0e3-79b6-43fc-a6fe-dfc1d007be61" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_1e74eac1-c96a-4123-99be-11431883ab7a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_1e74eac1-c96a-4123-99be-11431883ab7a_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_1e74eac1-c96a-4123-99be-11431883ab7a" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_1e74eac1-c96a-4123-99be-11431883ab7a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_58fed4ab-822f-47d7-beab-1ff447a1e2a8" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_1e74eac1-c96a-4123-99be-11431883ab7a" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_58fed4ab-822f-47d7-beab-1ff447a1e2a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_AnnArborMichiganMember_f77a9244-800b-42fe-9723-cae98a202374" xlink:href="vcel-20230930.xsd#vcel_AnnArborMichiganMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_58fed4ab-822f-47d7-beab-1ff447a1e2a8" xlink:to="loc_vcel_AnnArborMichiganMember_f77a9244-800b-42fe-9723-cae98a202374" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_A25NetworkDriveBurlingtonMassachusettsMember_d910ccd5-2bb2-4a45-8cb2-7ab8d6b35b17" xlink:href="vcel-20230930.xsd#vcel_A25NetworkDriveBurlingtonMassachusettsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_58fed4ab-822f-47d7-beab-1ff447a1e2a8" xlink:to="loc_vcel_A25NetworkDriveBurlingtonMassachusettsMember_d910ccd5-2bb2-4a45-8cb2-7ab8d6b35b17" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/InvestmentsDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#InvestmentsDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/InvestmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketableSecuritiesLineItems_479dc3a6-0e97-4027-ac0a-edc176986020" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MarketableSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_d6401d5e-2cec-4d22-9259-7d7430af91ee" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MarketableSecuritiesLineItems_479dc3a6-0e97-4027-ac0a-edc176986020" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_d6401d5e-2cec-4d22-9259-7d7430af91ee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_81890d67-1b4f-4ac7-aabe-7601b5ee8eae" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MarketableSecuritiesLineItems_479dc3a6-0e97-4027-ac0a-edc176986020" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_81890d67-1b4f-4ac7-aabe-7601b5ee8eae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_c7b3ef1a-c66f-4924-82e8-0e5ba24c1c12" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MarketableSecuritiesLineItems_479dc3a6-0e97-4027-ac0a-edc176986020" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_c7b3ef1a-c66f-4924-82e8-0e5ba24c1c12" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_4e54d8c4-9ecd-4343-82dc-e04f57a48011" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MarketableSecuritiesLineItems_479dc3a6-0e97-4027-ac0a-edc176986020" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_4e54d8c4-9ecd-4343-82dc-e04f57a48011" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_e0e3d048-663e-4182-86b3-fd4f6c8d5873" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MarketableSecuritiesLineItems_479dc3a6-0e97-4027-ac0a-edc176986020" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_e0e3d048-663e-4182-86b3-fd4f6c8d5873" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_DebtSecuritiesAvailableForSaleContractualMaturityPeriod_3ec00afe-4a7f-4d1c-9cb7-059deb553830" xlink:href="vcel-20230930.xsd#vcel_DebtSecuritiesAvailableForSaleContractualMaturityPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MarketableSecuritiesLineItems_479dc3a6-0e97-4027-ac0a-edc176986020" xlink:to="loc_vcel_DebtSecuritiesAvailableForSaleContractualMaturityPeriod_3ec00afe-4a7f-4d1c-9cb7-059deb553830" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_f825acad-d877-4b27-ae5d-bd9366f2f024" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MarketableSecuritiesLineItems_479dc3a6-0e97-4027-ac0a-edc176986020" xlink:to="loc_us-gaap_AssetImpairmentCharges_f825acad-d877-4b27-ae5d-bd9366f2f024" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketableSecuritiesTable_8c863405-390a-4b7c-b959-2ce7db35a1da" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MarketableSecuritiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_MarketableSecuritiesLineItems_479dc3a6-0e97-4027-ac0a-edc176986020" xlink:to="loc_us-gaap_MarketableSecuritiesTable_8c863405-390a-4b7c-b959-2ce7db35a1da" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_919c99ac-ea81-43de-9d5c-79d234c8674a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_MarketableSecuritiesTable_8c863405-390a-4b7c-b959-2ce7db35a1da" xlink:to="loc_us-gaap_FinancialInstrumentAxis_919c99ac-ea81-43de-9d5c-79d234c8674a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_919c99ac-ea81-43de-9d5c-79d234c8674a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_919c99ac-ea81-43de-9d5c-79d234c8674a" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_919c99ac-ea81-43de-9d5c-79d234c8674a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e06efe12-b9fc-4c3b-a981-437109aa3597" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_919c99ac-ea81-43de-9d5c-79d234c8674a" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e06efe12-b9fc-4c3b-a981-437109aa3597" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_048d6f65-0de6-4c2e-940f-29bf2257de26" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e06efe12-b9fc-4c3b-a981-437109aa3597" xlink:to="loc_us-gaap_CommercialPaperMember_048d6f65-0de6-4c2e-940f-29bf2257de26" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_67e416a6-29f2-417f-bc3f-dc9c37d11ce8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e06efe12-b9fc-4c3b-a981-437109aa3597" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_67e416a6-29f2-417f-bc3f-dc9c37d11ce8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_51964ea7-a1a3-4c23-a127-10e0cc6d023a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e06efe12-b9fc-4c3b-a981-437109aa3597" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_51964ea7-a1a3-4c23-a127-10e0cc6d023a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_8b540d41-9ff3-4f93-819a-a4a931cd7bc4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_MarketableSecuritiesTable_8c863405-390a-4b7c-b959-2ce7db35a1da" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_8b540d41-9ff3-4f93-819a-a4a931cd7bc4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_8b540d41-9ff3-4f93-819a-a4a931cd7bc4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_8b540d41-9ff3-4f93-819a-a4a931cd7bc4" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_8b540d41-9ff3-4f93-819a-a4a931cd7bc4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_3ae18189-a855-440d-a5c3-ffb882de55c2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_8b540d41-9ff3-4f93-819a-a4a931cd7bc4" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_3ae18189-a855-440d-a5c3-ffb882de55c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_eec0e593-d3df-4246-93e5-64a2d5adf69b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_3ae18189-a855-440d-a5c3-ffb882de55c2" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_eec0e593-d3df-4246-93e5-64a2d5adf69b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LongtermInvestmentsMember_40487dd7-cb6f-48e5-bac3-d8086013823a" xlink:href="vcel-20230930.xsd#vcel_LongtermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_3ae18189-a855-440d-a5c3-ffb882de55c2" xlink:to="loc_vcel_LongtermInvestmentsMember_40487dd7-cb6f-48e5-bac3-d8086013823a" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/FairValueMeasurementsDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#FairValueMeasurementsDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/FairValueMeasurementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_be268c3b-1357-497d-a769-1f9bf53e1b87" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_f2ca0ffb-b73e-4073-bb42-f95e1e93648a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_be268c3b-1357-497d-a769-1f9bf53e1b87" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_f2ca0ffb-b73e-4073-bb42-f95e1e93648a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_e0953ad5-ac9b-4e09-ba3d-fe59d589104d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_be268c3b-1357-497d-a769-1f9bf53e1b87" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_e0953ad5-ac9b-4e09-ba3d-fe59d589104d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_d3a51df7-6cb3-485b-9467-17614ad1d041" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_be268c3b-1357-497d-a769-1f9bf53e1b87" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_d3a51df7-6cb3-485b-9467-17614ad1d041" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_b3170d74-62df-4ca1-849a-0cf3c4d04a40" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_be268c3b-1357-497d-a769-1f9bf53e1b87" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_b3170d74-62df-4ca1-849a-0cf3c4d04a40" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_be727ad3-553a-4dfe-aff3-0b300d0bc773" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_b3170d74-62df-4ca1-849a-0cf3c4d04a40" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_be727ad3-553a-4dfe-aff3-0b300d0bc773" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_be727ad3-553a-4dfe-aff3-0b300d0bc773_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_be727ad3-553a-4dfe-aff3-0b300d0bc773" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_be727ad3-553a-4dfe-aff3-0b300d0bc773_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_8bcbc39e-5758-477f-a245-1da79ae857ed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_be727ad3-553a-4dfe-aff3-0b300d0bc773" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_8bcbc39e-5758-477f-a245-1da79ae857ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_1dcca000-2f02-47d5-9113-356b334c5443" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_8bcbc39e-5758-477f-a245-1da79ae857ed" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_1dcca000-2f02-47d5-9113-356b334c5443" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_11c39736-6c92-4483-b3b7-191fbac08d8a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_b3170d74-62df-4ca1-849a-0cf3c4d04a40" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_11c39736-6c92-4483-b3b7-191fbac08d8a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_11c39736-6c92-4483-b3b7-191fbac08d8a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_11c39736-6c92-4483-b3b7-191fbac08d8a" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_11c39736-6c92-4483-b3b7-191fbac08d8a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_8c836908-7d73-49e1-abfe-1ed7932bd7a4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_11c39736-6c92-4483-b3b7-191fbac08d8a" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_8c836908-7d73-49e1-abfe-1ed7932bd7a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_cdc2d0da-a309-409e-80d1-6b90cd527d36" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_8c836908-7d73-49e1-abfe-1ed7932bd7a4" xlink:to="loc_us-gaap_MoneyMarketFundsMember_cdc2d0da-a309-409e-80d1-6b90cd527d36" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_c7c9f999-9b5d-42cc-b8fc-71016c4b91e9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_b3170d74-62df-4ca1-849a-0cf3c4d04a40" xlink:to="loc_us-gaap_FinancialInstrumentAxis_c7c9f999-9b5d-42cc-b8fc-71016c4b91e9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c7c9f999-9b5d-42cc-b8fc-71016c4b91e9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_c7c9f999-9b5d-42cc-b8fc-71016c4b91e9" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c7c9f999-9b5d-42cc-b8fc-71016c4b91e9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_74981d86-848f-456c-b70b-061c740e416d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_c7c9f999-9b5d-42cc-b8fc-71016c4b91e9" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_74981d86-848f-456c-b70b-061c740e416d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember_b5c72a75-dcd2-4e8d-8787-c7d0b79d0d8b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_74981d86-848f-456c-b70b-061c740e416d" xlink:to="loc_us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember_b5c72a75-dcd2-4e8d-8787-c7d0b79d0d8b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNoteSecuritiesMember_962abb7f-1a68-4898-a79c-287ea8164a79" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CorporateNoteSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_74981d86-848f-456c-b70b-061c740e416d" xlink:to="loc_us-gaap_CorporateNoteSecuritiesMember_962abb7f-1a68-4898-a79c-287ea8164a79" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentDebtSecuritiesMember_0766da29-610f-4c7b-b4b2-a8c4a6540318" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_USGovernmentDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_74981d86-848f-456c-b70b-061c740e416d" xlink:to="loc_us-gaap_USGovernmentDebtSecuritiesMember_0766da29-610f-4c7b-b4b2-a8c4a6540318" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_88713416-00cd-428a-bfe9-9bcb60b899dc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_74981d86-848f-456c-b70b-061c740e416d" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_88713416-00cd-428a-bfe9-9bcb60b899dc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_da58da6d-cec5-4f47-822f-c79762623911" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_b3170d74-62df-4ca1-849a-0cf3c4d04a40" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_da58da6d-cec5-4f47-822f-c79762623911" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_da58da6d-cec5-4f47-822f-c79762623911_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_da58da6d-cec5-4f47-822f-c79762623911" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_da58da6d-cec5-4f47-822f-c79762623911_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b37f1334-ddbb-4509-a305-1deee7d10dbc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_da58da6d-cec5-4f47-822f-c79762623911" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b37f1334-ddbb-4509-a305-1deee7d10dbc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_88717877-0f56-4566-92f0-d8cd920971f2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b37f1334-ddbb-4509-a305-1deee7d10dbc" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_88717877-0f56-4566-92f0-d8cd920971f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_55e23353-d319-483c-9ed6-198660a07ec4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b37f1334-ddbb-4509-a305-1deee7d10dbc" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_55e23353-d319-483c-9ed6-198660a07ec4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_d1d56021-97d8-4bf0-98c8-6e8d11b6b5c1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b37f1334-ddbb-4509-a305-1deee7d10dbc" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_d1d56021-97d8-4bf0-98c8-6e8d11b6b5c1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_231280d3-f5fa-4f1a-8888-e4f01aeb8653" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_b3170d74-62df-4ca1-849a-0cf3c4d04a40" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_231280d3-f5fa-4f1a-8888-e4f01aeb8653" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_231280d3-f5fa-4f1a-8888-e4f01aeb8653_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_231280d3-f5fa-4f1a-8888-e4f01aeb8653" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_231280d3-f5fa-4f1a-8888-e4f01aeb8653_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_a2582efb-89ad-4237-bc65-dba5a07ef96c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_231280d3-f5fa-4f1a-8888-e4f01aeb8653" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_a2582efb-89ad-4237-bc65-dba5a07ef96c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsMember_6f993b32-1d87-450b-958b-6843f14bb55e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_a2582efb-89ad-4237-bc65-dba5a07ef96c" xlink:to="loc_us-gaap_CashAndCashEquivalentsMember_6f993b32-1d87-450b-958b-6843f14bb55e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/RevolvingCreditAgreementDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#RevolvingCreditAgreementDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/RevolvingCreditAgreementDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_a4244798-dbf0-4198-95c1-db556a38e172" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_5b7fce27-1fac-45d1-a568-f6dc05214bd5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a4244798-dbf0-4198-95c1-db556a38e172" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_5b7fce27-1fac-45d1-a568-f6dc05214bd5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_ddb67ec0-cae0-4351-bb33-dd1903983a32" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a4244798-dbf0-4198-95c1-db556a38e172" xlink:to="loc_us-gaap_DebtInstrumentTerm_ddb67ec0-cae0-4351-bb33-dd1903983a32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_53d95fac-d7a4-4418-b1cf-963d96c052c3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a4244798-dbf0-4198-95c1-db556a38e172" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_53d95fac-d7a4-4418-b1cf-963d96c052c3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_0b04111c-0c7b-41bb-bc71-fadde45234da" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a4244798-dbf0-4198-95c1-db556a38e172" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_0b04111c-0c7b-41bb-bc71-fadde45234da" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_8cced3e8-e680-4962-89a6-deb43ac4ff7c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a4244798-dbf0-4198-95c1-db556a38e172" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_8cced3e8-e680-4962-89a6-deb43ac4ff7c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_b3b7e9df-bbca-467f-a398-47de5080ffcb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a4244798-dbf0-4198-95c1-db556a38e172" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_b3b7e9df-bbca-467f-a398-47de5080ffcb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_01d9a82b-f5f2-456f-abe2-090c4eddecf6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a4244798-dbf0-4198-95c1-db556a38e172" xlink:to="loc_us-gaap_LineOfCredit_01d9a82b-f5f2-456f-abe2-090c4eddecf6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_DebtInstrumentCovenantLeverageRatioMaximum_b0d74e94-85ba-421b-bc37-84b8bb7913a4" xlink:href="vcel-20230930.xsd#vcel_DebtInstrumentCovenantLeverageRatioMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a4244798-dbf0-4198-95c1-db556a38e172" xlink:to="loc_vcel_DebtInstrumentCovenantLeverageRatioMaximum_b0d74e94-85ba-421b-bc37-84b8bb7913a4" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_DebtInstrumentCovenantIncreaseOptionLeverageRatioMaximum_bb780ca3-9f9f-4177-ab7b-2d197bdc6266" xlink:href="vcel-20230930.xsd#vcel_DebtInstrumentCovenantIncreaseOptionLeverageRatioMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a4244798-dbf0-4198-95c1-db556a38e172" xlink:to="loc_vcel_DebtInstrumentCovenantIncreaseOptionLeverageRatioMaximum_bb780ca3-9f9f-4177-ab7b-2d197bdc6266" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_caedc74e-d953-4117-bda9-c24e41b5be77" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a4244798-dbf0-4198-95c1-db556a38e172" xlink:to="loc_us-gaap_DebtInstrumentTable_caedc74e-d953-4117-bda9-c24e41b5be77" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_397bc05f-8f84-4a4c-bbdd-b962dbbc611e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_caedc74e-d953-4117-bda9-c24e41b5be77" xlink:to="loc_us-gaap_CreditFacilityAxis_397bc05f-8f84-4a4c-bbdd-b962dbbc611e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_397bc05f-8f84-4a4c-bbdd-b962dbbc611e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_397bc05f-8f84-4a4c-bbdd-b962dbbc611e" xlink:to="loc_us-gaap_CreditFacilityDomain_397bc05f-8f84-4a4c-bbdd-b962dbbc611e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_42620726-6543-4712-bea7-b6c22ec20ba9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_397bc05f-8f84-4a4c-bbdd-b962dbbc611e" xlink:to="loc_us-gaap_CreditFacilityDomain_42620726-6543-4712-bea7-b6c22ec20ba9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_87f363e9-d8cc-494a-9db8-5b9b8c1bf928" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_42620726-6543-4712-bea7-b6c22ec20ba9" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_87f363e9-d8cc-494a-9db8-5b9b8c1bf928" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_cb587473-0a78-4b78-95bc-0b7c1aa465ca" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_42620726-6543-4712-bea7-b6c22ec20ba9" xlink:to="loc_us-gaap_LetterOfCreditMember_cb587473-0a78-4b78-95bc-0b7c1aa465ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_a6c53dfe-e28d-4f6b-b420-21b9aaea994f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_caedc74e-d953-4117-bda9-c24e41b5be77" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_a6c53dfe-e28d-4f6b-b420-21b9aaea994f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_a6c53dfe-e28d-4f6b-b420-21b9aaea994f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_a6c53dfe-e28d-4f6b-b420-21b9aaea994f" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_a6c53dfe-e28d-4f6b-b420-21b9aaea994f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_4bc19891-13b8-412c-b636-b661fb1760a2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_a6c53dfe-e28d-4f6b-b420-21b9aaea994f" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_4bc19891-13b8-412c-b636-b661fb1760a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_bd268bee-d423-4744-b15e-844bed362fe2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_4bc19891-13b8-412c-b636-b661fb1760a2" xlink:to="loc_us-gaap_LineOfCreditMember_bd268bee-d423-4744-b15e-844bed362fe2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_1016d1fe-0fc3-4350-ad7b-423f42179213" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_caedc74e-d953-4117-bda9-c24e41b5be77" xlink:to="loc_us-gaap_VariableRateAxis_1016d1fe-0fc3-4350-ad7b-423f42179213" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_1016d1fe-0fc3-4350-ad7b-423f42179213_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_1016d1fe-0fc3-4350-ad7b-423f42179213" xlink:to="loc_us-gaap_VariableRateDomain_1016d1fe-0fc3-4350-ad7b-423f42179213_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_ea3d88ba-3d81-478f-8321-fd10aa7b6d37" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_1016d1fe-0fc3-4350-ad7b-423f42179213" xlink:to="loc_us-gaap_VariableRateDomain_ea3d88ba-3d81-478f-8321-fd10aa7b6d37" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_SecuredOvernightFinancingRateSOFRMember_02e5f3ec-7f66-4f34-a94f-57175517c5d6" xlink:href="vcel-20230930.xsd#vcel_SecuredOvernightFinancingRateSOFRMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_ea3d88ba-3d81-478f-8321-fd10aa7b6d37" xlink:to="loc_vcel_SecuredOvernightFinancingRateSOFRMember_02e5f3ec-7f66-4f34-a94f-57175517c5d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BaseRateMember_a1d0ef6b-5082-4b10-80d1-b9e13963671c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BaseRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_ea3d88ba-3d81-478f-8321-fd10aa7b6d37" xlink:to="loc_us-gaap_BaseRateMember_a1d0ef6b-5082-4b10-80d1-b9e13963671c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_95f07d9c-884f-4b95-aa72-6e3d45f9421f" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_caedc74e-d953-4117-bda9-c24e41b5be77" xlink:to="loc_srt_RangeAxis_95f07d9c-884f-4b95-aa72-6e3d45f9421f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_95f07d9c-884f-4b95-aa72-6e3d45f9421f_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_95f07d9c-884f-4b95-aa72-6e3d45f9421f" xlink:to="loc_srt_RangeMember_95f07d9c-884f-4b95-aa72-6e3d45f9421f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_41ba9656-41b9-4c57-a05e-33632c418a97" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_95f07d9c-884f-4b95-aa72-6e3d45f9421f" xlink:to="loc_srt_RangeMember_41ba9656-41b9-4c57-a05e-33632c418a97" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_33033610-eaff-45b5-a530-80ff0fe479e9" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_41ba9656-41b9-4c57-a05e-33632c418a97" xlink:to="loc_srt_MinimumMember_33033610-eaff-45b5-a530-80ff0fe479e9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_edeb33f5-4125-42c0-b219-da142f560e1d" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_41ba9656-41b9-4c57-a05e-33632c418a97" xlink:to="loc_srt_MaximumMember_edeb33f5-4125-42c0-b219-da142f560e1d" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/StockBasedCompensationExpenseDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#StockBasedCompensationExpenseDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/StockBasedCompensationExpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_83547493-e1b8-47ce-9ecd-5c226b5d484e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_4e3bf226-cd2e-4cde-977f-7e9e10476d48" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_83547493-e1b8-47ce-9ecd-5c226b5d484e" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_4e3bf226-cd2e-4cde-977f-7e9e10476d48" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_e37a0fdd-5c6e-4e39-8858-e2875cd7c682" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_83547493-e1b8-47ce-9ecd-5c226b5d484e" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_e37a0fdd-5c6e-4e39-8858-e2875cd7c682" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_82b76873-e677-4476-b79d-206a1df39633" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_e37a0fdd-5c6e-4e39-8858-e2875cd7c682" xlink:to="loc_us-gaap_AwardTypeAxis_82b76873-e677-4476-b79d-206a1df39633" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_82b76873-e677-4476-b79d-206a1df39633_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_82b76873-e677-4476-b79d-206a1df39633" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_82b76873-e677-4476-b79d-206a1df39633_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b3db51d9-29ef-4a4d-976d-0fa064464b85" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_82b76873-e677-4476-b79d-206a1df39633" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b3db51d9-29ef-4a4d-976d-0fa064464b85" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_EmployeeStockAndEmployeeStockOptionMember_744f4f37-4520-41fb-800a-69f8f814f2ec" xlink:href="vcel-20230930.xsd#vcel_EmployeeStockAndEmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b3db51d9-29ef-4a4d-976d-0fa064464b85" xlink:to="loc_vcel_EmployeeStockAndEmployeeStockOptionMember_744f4f37-4520-41fb-800a-69f8f814f2ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_2a2cc9e4-8f93-46ff-9990-af54d9839f7e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_e37a0fdd-5c6e-4e39-8858-e2875cd7c682" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_2a2cc9e4-8f93-46ff-9990-af54d9839f7e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_2a2cc9e4-8f93-46ff-9990-af54d9839f7e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_2a2cc9e4-8f93-46ff-9990-af54d9839f7e" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_2a2cc9e4-8f93-46ff-9990-af54d9839f7e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_9c27e52f-e1f6-4d00-9fd8-4c883158d358" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_2a2cc9e4-8f93-46ff-9990-af54d9839f7e" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_9c27e52f-e1f6-4d00-9fd8-4c883158d358" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_65d12ca3-cbac-44b8-948c-1cc9ccdc042e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_9c27e52f-e1f6-4d00-9fd8-4c883158d358" xlink:to="loc_us-gaap_CostOfSalesMember_65d12ca3-cbac-44b8-948c-1cc9ccdc042e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_7392194f-5340-4adc-91eb-9f896a37e16e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_9c27e52f-e1f6-4d00-9fd8-4c883158d358" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_7392194f-5340-4adc-91eb-9f896a37e16e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_a981d45f-09c2-4060-8c6a-c123bdc6e23f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_9c27e52f-e1f6-4d00-9fd8-4c883158d358" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_a981d45f-09c2-4060-8c6a-c123bdc6e23f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/StockBasedCompensationNarrativeDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#StockBasedCompensationNarrativeDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/StockBasedCompensationNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f22ca4e6-314f-40f1-b3de-6c70c4e3cf5c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_51dc6842-0da5-4720-b78c-2f073e8c850c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f22ca4e6-314f-40f1-b3de-6c70c4e3cf5c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_51dc6842-0da5-4720-b78c-2f073e8c850c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_afba15ca-d29b-4d60-a7e3-a977a8c8ed2d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f22ca4e6-314f-40f1-b3de-6c70c4e3cf5c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_afba15ca-d29b-4d60-a7e3-a977a8c8ed2d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_24656003-257f-4376-9310-f212d24aa459" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f22ca4e6-314f-40f1-b3de-6c70c4e3cf5c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_24656003-257f-4376-9310-f212d24aa459" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_ce3597ea-12c6-4f0c-a827-b92ad8e20a2b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f22ca4e6-314f-40f1-b3de-6c70c4e3cf5c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_ce3597ea-12c6-4f0c-a827-b92ad8e20a2b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3c47e164-a5bf-4931-b8c9-f29b4b889059" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f22ca4e6-314f-40f1-b3de-6c70c4e3cf5c" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3c47e164-a5bf-4931-b8c9-f29b4b889059" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_a4e25d56-6a83-4c64-876f-6281bb5524f1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3c47e164-a5bf-4931-b8c9-f29b4b889059" xlink:to="loc_us-gaap_AwardTypeAxis_a4e25d56-6a83-4c64-876f-6281bb5524f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a4e25d56-6a83-4c64-876f-6281bb5524f1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_a4e25d56-6a83-4c64-876f-6281bb5524f1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a4e25d56-6a83-4c64-876f-6281bb5524f1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d7ece2c5-f5ea-475c-bfb1-8db825cd6821" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_a4e25d56-6a83-4c64-876f-6281bb5524f1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d7ece2c5-f5ea-475c-bfb1-8db825cd6821" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_2f6aa84c-58f6-45c1-8f69-9f6a3f0cb590" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d7ece2c5-f5ea-475c-bfb1-8db825cd6821" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_2f6aa84c-58f6-45c1-8f69-9f6a3f0cb590" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/NetLossPerCommonShareDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#NetLossPerCommonShareDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/NetLossPerCommonShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_aea46911-3212-4a9c-87b3-bd51af8a1878" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAbstract_faf1ace5-cce6-4ac4-ad43-d0363aacaf44" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLossAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_aea46911-3212-4a9c-87b3-bd51af8a1878" xlink:to="loc_us-gaap_NetIncomeLossAbstract_faf1ace5-cce6-4ac4-ad43-d0363aacaf44" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_230b04fc-6c42-4cd5-98fd-d3e424ac49d4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAbstract_faf1ace5-cce6-4ac4-ad43-d0363aacaf44" xlink:to="loc_us-gaap_NetIncomeLoss_230b04fc-6c42-4cd5-98fd-d3e424ac49d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_13363b13-ef87-4f4c-973a-b6c605df3beb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAbstract_faf1ace5-cce6-4ac4-ad43-d0363aacaf44" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_13363b13-ef87-4f4c-973a-b6c605df3beb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_358b705a-4b24-4ee3-a349-3a26114e1ac3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAbstract_faf1ace5-cce6-4ac4-ad43-d0363aacaf44" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_358b705a-4b24-4ee3-a349-3a26114e1ac3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_86a1596d-44f4-4cfa-b8a3-c88fbdabec1b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAbstract_faf1ace5-cce6-4ac4-ad43-d0363aacaf44" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_86a1596d-44f4-4cfa-b8a3-c88fbdabec1b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_41aac5e2-b2a5-4780-8d68-75adbe744847" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAbstract_faf1ace5-cce6-4ac4-ad43-d0363aacaf44" xlink:to="loc_us-gaap_EarningsPerShareBasic_41aac5e2-b2a5-4780-8d68-75adbe744847" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_cdc222b0-a7d5-492e-96b8-8b8f256f87b0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAbstract_faf1ace5-cce6-4ac4-ad43-d0363aacaf44" xlink:to="loc_us-gaap_EarningsPerShareDiluted_cdc222b0-a7d5-492e-96b8-8b8f256f87b0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_da5fd9f9-bd02-4886-934f-e4cf98a75458" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_aea46911-3212-4a9c-87b3-bd51af8a1878" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_da5fd9f9-bd02-4886-934f-e4cf98a75458" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_f1c670d9-3ca2-4876-932a-3f18478bca56" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_da5fd9f9-bd02-4886-934f-e4cf98a75458" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_f1c670d9-3ca2-4876-932a-3f18478bca56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_b614d0f1-1b65-4625-ba1e-a60e97a8295a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_aea46911-3212-4a9c-87b3-bd51af8a1878" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_b614d0f1-1b65-4625-ba1e-a60e97a8295a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_6435466a-4938-41a6-8c87-c1eec384821d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_b614d0f1-1b65-4625-ba1e-a60e97a8295a" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_6435466a-4938-41a6-8c87-c1eec384821d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_6435466a-4938-41a6-8c87-c1eec384821d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_6435466a-4938-41a6-8c87-c1eec384821d" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_6435466a-4938-41a6-8c87-c1eec384821d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_9a4815c8-e9fa-48d4-84c0-7db6635c17af" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_6435466a-4938-41a6-8c87-c1eec384821d" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_9a4815c8-e9fa-48d4-84c0-7db6635c17af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_ee35c428-dc18-4562-b018-781b1c6fdc62" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_9a4815c8-e9fa-48d4-84c0-7db6635c17af" xlink:to="loc_us-gaap_EmployeeStockOptionMember_ee35c428-dc18-4562-b018-781b1c6fdc62" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_bcdbc311-7f23-4d58-a75b-c289c8ebfb41" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_9a4815c8-e9fa-48d4-84c0-7db6635c17af" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_bcdbc311-7f23-4d58-a75b-c289c8ebfb41" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://vcel.com/role/NexoBridLicenseandSupplyAgreementsDetails" xlink:type="simple" xlink:href="vcel-20230930.xsd#NexoBridLicenseandSupplyAgreementsDetails"/>
  <link:definitionLink xlink:role="http://vcel.com/role/NexoBridLicenseandSupplyAgreementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_9476b76e-3792-4fb7-b9dc-c04589f898e4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LicenseAgreementConsideration_a61aa273-6f60-45bd-9bb0-7ac00722103c" xlink:href="vcel-20230930.xsd#vcel_LicenseAgreementConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9476b76e-3792-4fb7-b9dc-c04589f898e4" xlink:to="loc_vcel_LicenseAgreementConsideration_a61aa273-6f60-45bd-9bb0-7ac00722103c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LicenseAgreementContingentConsideration_468edb1f-c4eb-4b9d-b3c1-421a91229eb7" xlink:href="vcel-20230930.xsd#vcel_LicenseAgreementContingentConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9476b76e-3792-4fb7-b9dc-c04589f898e4" xlink:to="loc_vcel_LicenseAgreementContingentConsideration_468edb1f-c4eb-4b9d-b3c1-421a91229eb7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LicenseAgreementContingentConsiderationMaximum_e3175533-3c9a-4bdf-8a37-916d2da7c6db" xlink:href="vcel-20230930.xsd#vcel_LicenseAgreementContingentConsiderationMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9476b76e-3792-4fb7-b9dc-c04589f898e4" xlink:to="loc_vcel_LicenseAgreementContingentConsiderationMaximum_e3175533-3c9a-4bdf-8a37-916d2da7c6db" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LicenseAgreementInitialMilestoneSales_8fd62316-a603-49db-ab76-a63ce334c903" xlink:href="vcel-20230930.xsd#vcel_LicenseAgreementInitialMilestoneSales"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9476b76e-3792-4fb7-b9dc-c04589f898e4" xlink:to="loc_vcel_LicenseAgreementInitialMilestoneSales_8fd62316-a603-49db-ab76-a63ce334c903" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LicenseAgreementSupplyAgreementTerm_1a09a87e-570d-48d5-b7aa-1dcf22bf259d" xlink:href="vcel-20230930.xsd#vcel_LicenseAgreementSupplyAgreementTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9476b76e-3792-4fb7-b9dc-c04589f898e4" xlink:to="loc_vcel_LicenseAgreementSupplyAgreementTerm_1a09a87e-570d-48d5-b7aa-1dcf22bf259d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LicenseAgreementSupplyAgreementRenewalTerm_04d49eda-e814-40d8-af07-79c9c8037801" xlink:href="vcel-20230930.xsd#vcel_LicenseAgreementSupplyAgreementRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9476b76e-3792-4fb7-b9dc-c04589f898e4" xlink:to="loc_vcel_LicenseAgreementSupplyAgreementRenewalTerm_04d49eda-e814-40d8-af07-79c9c8037801" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_LicenseAgreementAdditionalFunding_7b8a1a5a-7531-43e6-b23c-80002336c57e" xlink:href="vcel-20230930.xsd#vcel_LicenseAgreementAdditionalFunding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9476b76e-3792-4fb7-b9dc-c04589f898e4" xlink:to="loc_vcel_LicenseAgreementAdditionalFunding_7b8a1a5a-7531-43e6-b23c-80002336c57e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e72e1c8e-cef6-415a-9854-ca90a4acb5eb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_9476b76e-3792-4fb7-b9dc-c04589f898e4" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e72e1c8e-cef6-415a-9854-ca90a4acb5eb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_ae5ac945-9d38-4a37-9088-16dc22e4b81b" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e72e1c8e-cef6-415a-9854-ca90a4acb5eb" xlink:to="loc_srt_CounterpartyNameAxis_ae5ac945-9d38-4a37-9088-16dc22e4b81b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ae5ac945-9d38-4a37-9088-16dc22e4b81b_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_ae5ac945-9d38-4a37-9088-16dc22e4b81b" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ae5ac945-9d38-4a37-9088-16dc22e4b81b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3f73cbd7-8c34-482b-9546-6fa568520225" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_ae5ac945-9d38-4a37-9088-16dc22e4b81b" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3f73cbd7-8c34-482b-9546-6fa568520225" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_MediWoundLtdMember_cf866357-329e-4cb5-a8dc-924de28c6465" xlink:href="vcel-20230930.xsd#vcel_MediWoundLtdMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3f73cbd7-8c34-482b-9546-6fa568520225" xlink:to="loc_vcel_MediWoundLtdMember_cf866357-329e-4cb5-a8dc-924de28c6465" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-roles-2023.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#AwardTypeOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_EmployeeStockAndEmployeeStockOptionMember_5bc7cac0-062f-42bb-87df-e826a1e46efa" xlink:href="vcel-20230930.xsd#vcel_EmployeeStockAndEmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_vcel_EmployeeStockAndEmployeeStockOptionMember_5bc7cac0-062f-42bb-87df-e826a1e46efa" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#IndividualsOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllIndividualsMember" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#ecd_AllIndividualsMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_RobertZerbeMember_a15ab47c-61f7-481a-8c50-23c34244fa81" xlink:href="vcel-20230930.xsd#vcel_RobertZerbeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_vcel_RobertZerbeMember_a15ab47c-61f7-481a-8c50-23c34244fa81" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_JonathanHopperMember_0e1242e2-8f56-4e6a-b90e-7afd283d4294" xlink:href="vcel-20230930.xsd#vcel_JonathanHopperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_vcel_JonathanHopperMember_0e1242e2-8f56-4e6a-b90e-7afd283d4294" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_MichaelHalpinMember_1856193f-0521-42d7-8aa1-439a9dd3e422" xlink:href="vcel-20230930.xsd#vcel_MichaelHalpinMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_vcel_MichaelHalpinMember_1856193f-0521-42d7-8aa1-439a9dd3e422" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_DominickColangeloMember_4f535857-645e-431d-8ace-c39760ef2be6" xlink:href="vcel-20230930.xsd#vcel_DominickColangeloMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_vcel_DominickColangeloMember_4f535857-645e-431d-8ace-c39760ef2be6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_vcel_JonathanSiegalMember_3c6fe8fd-0198-41a2-836f-2af99423f1b1" xlink:href="vcel-20230930.xsd#vcel_JonathanSiegalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_vcel_JonathanSiegalMember_3c6fe8fd-0198-41a2-836f-2af99423f1b1" xlink:type="arc" order="6"/>
  </link:definitionLink>
</link:linkbase>
