

<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <roleRef roleURI="http://vcel.com/role/Acquisitions" xlink:href="astm-20150930.xsd#Acquisitions" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/AcquisitionsDetails" xlink:href="astm-20150930.xsd#AcquisitionsDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/AcquisitionsTables" xlink:href="astm-20150930.xsd#AcquisitionsTables" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/BasisOfPresentation" xlink:href="astm-20150930.xsd#BasisOfPresentation" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/CommitmentsAndContingencies" xlink:href="astm-20150930.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/CommitmentsAndContingenciesDetails" xlink:href="astm-20150930.xsd#CommitmentsAndContingenciesDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/CommitmentsAndContingenciesDetailsCalc2" xlink:href="astm-20150930.xsd#CommitmentsAndContingenciesDetailsCalc2" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/CommitmentsAndContingenciesTables" xlink:href="astm-20150930.xsd#CommitmentsAndContingenciesTables" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/ConcentrationOfCreditRisk" xlink:href="astm-20150930.xsd#ConcentrationOfCreditRisk" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/ConcentrationOfCreditRiskDetails" xlink:href="astm-20150930.xsd#ConcentrationOfCreditRiskDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/CondensedConsolidatedBalanceSheets" xlink:href="astm-20150930.xsd#CondensedConsolidatedBalanceSheets" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/CondensedConsolidatedBalanceSheetsParenthetical" xlink:href="astm-20150930.xsd#CondensedConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/CondensedConsolidatedStatementsOfCashFlows" xlink:href="astm-20150930.xsd#CondensedConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/CondensedConsolidatedStatementsOfComprehensiveLoss" xlink:href="astm-20150930.xsd#CondensedConsolidatedStatementsOfComprehensiveLoss" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/CondensedConsolidatedStatementsOfOperations" xlink:href="astm-20150930.xsd#CondensedConsolidatedStatementsOfOperations" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/DocumentAndEntityInformation" xlink:href="astm-20150930.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/FairValueMeasurements" xlink:href="astm-20150930.xsd#FairValueMeasurements" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/FairValueMeasurementsLevel3InputsDetails" xlink:href="astm-20150930.xsd#FairValueMeasurementsLevel3InputsDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/FairValueMeasurementsRecurringBasisDetails" xlink:href="astm-20150930.xsd#FairValueMeasurementsRecurringBasisDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/FairValueMeasurementsTables" xlink:href="astm-20150930.xsd#FairValueMeasurementsTables" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/NetLossPerCommonShare" xlink:href="astm-20150930.xsd#NetLossPerCommonShare" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/NetLossPerCommonShareDetails" xlink:href="astm-20150930.xsd#NetLossPerCommonShareDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/NetLossPerCommonShareTables" xlink:href="astm-20150930.xsd#NetLossPerCommonShareTables" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/Organization" xlink:href="astm-20150930.xsd#Organization" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/OrganizationDetails" xlink:href="astm-20150930.xsd#OrganizationDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/PreferredStock" xlink:href="astm-20150930.xsd#PreferredStock" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/PreferredStockDetails" xlink:href="astm-20150930.xsd#PreferredStockDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/RecentAccountingPronouncements" xlink:href="astm-20150930.xsd#RecentAccountingPronouncements" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/RecentAccountingPronouncementsPolicies" xlink:href="astm-20150930.xsd#RecentAccountingPronouncementsPolicies" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/Restructuring" xlink:href="astm-20150930.xsd#Restructuring" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/RestructuringDetails" xlink:href="astm-20150930.xsd#RestructuringDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/SelectedBalanceSheetComponents" xlink:href="astm-20150930.xsd#SelectedBalanceSheetComponents" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/SelectedBalanceSheetComponentsAccruedExpensesDetails" xlink:href="astm-20150930.xsd#SelectedBalanceSheetComponentsAccruedExpensesDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/SelectedBalanceSheetComponentsIntangibleAssetsDetails" xlink:href="astm-20150930.xsd#SelectedBalanceSheetComponentsIntangibleAssetsDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/SelectedBalanceSheetComponentsInventoryDetails" xlink:href="astm-20150930.xsd#SelectedBalanceSheetComponentsInventoryDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/SelectedBalanceSheetComponentsPropertyPlantAndEquipmentDetails" xlink:href="astm-20150930.xsd#SelectedBalanceSheetComponentsPropertyPlantAndEquipmentDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/SelectedBalanceSheetComponentsTables" xlink:href="astm-20150930.xsd#SelectedBalanceSheetComponentsTables" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/ShareholdersEquity" xlink:href="astm-20150930.xsd#ShareholdersEquity" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/ShareholdersEquityDetails" xlink:href="astm-20150930.xsd#ShareholdersEquityDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/StockBasedCompensation" xlink:href="astm-20150930.xsd#StockBasedCompensation" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/StockBasedCompensationDetails" xlink:href="astm-20150930.xsd#StockBasedCompensationDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/StockBasedCompensationTables" xlink:href="astm-20150930.xsd#StockBasedCompensationTables" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/StockPurchaseWarrants" xlink:href="astm-20150930.xsd#StockPurchaseWarrants" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/StockPurchaseWarrantsDetails" xlink:href="astm-20150930.xsd#StockPurchaseWarrantsDetails" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/StockPurchaseWarrantsTables" xlink:href="astm-20150930.xsd#StockPurchaseWarrantsTables" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/SubsequentEvents" xlink:href="astm-20150930.xsd#SubsequentEvents" xlink:type="simple" />
  <roleRef roleURI="http://vcel.com/role/SubsequentEventsDetails" xlink:href="astm-20150930.xsd#SubsequentEventsDetails" xlink:type="simple" />
  <calculationLink xlink:role="http://vcel.com/role/Acquisitions" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/AcquisitionsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_ac850567-f89c-9ba5-f2b3-6d0674d77b7e" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross_731c2d9f-8aec-0326-36d0-f4e24cd26053" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationConsiderationTransferred1_ac850567-f89c-9ba5-f2b3-6d0674d77b7e" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross_731c2d9f-8aec-0326-36d0-f4e24cd26053" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred_abe4d133-fc59-6051-c686-18467199ac1b" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_BusinessCombinationConsiderationTransferred1_ac850567-f89c-9ba5-f2b3-6d0674d77b7e" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred_abe4d133-fc59-6051-c686-18467199ac1b" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://vcel.com/role/AcquisitionsTables" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/BasisOfPresentation" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/CommitmentsAndContingencies" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/CommitmentsAndContingenciesDetails" xlink:type="extended">
    <loc xlink:href="astm-20150930.xsd#astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDue" xlink:label="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDue_64F7D370D9A1CB3630D0C3AC9DFD90E3" xlink:type="locator" />
    <loc xlink:href="astm-20150930.xsd#astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueCurrent" xlink:label="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueCurrent_4ED2EFFEA83E0A5FDC53C3A9FDF8BF49" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDue_64F7D370D9A1CB3630D0C3AC9DFD90E3" xlink:to="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueCurrent_4ED2EFFEA83E0A5FDC53C3A9FDF8BF49" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsRemainderOfFiscalYear" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsRemainderOfFiscalYear_82703f3f-08db-c6b2-481a-9c81c1d5c009" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueCurrent_4ED2EFFEA83E0A5FDC53C3A9FDF8BF49" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsRemainderOfFiscalYear_82703f3f-08db-c6b2-481a-9c81c1d5c009" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsRemainderOfFiscalYear" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsRemainderOfFiscalYear_ee012fec-4307-1377-a21d-5433a513d0c2" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueCurrent_4ED2EFFEA83E0A5FDC53C3A9FDF8BF49" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsRemainderOfFiscalYear_ee012fec-4307-1377-a21d-5433a513d0c2" xlink:type="arc" />
    <loc xlink:href="astm-20150930.xsd#astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInTwoYears_FC3226A626870ADDF1BAC3ADBE4C3084" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDue_64F7D370D9A1CB3630D0C3AC9DFD90E3" xlink:to="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInTwoYears_FC3226A626870ADDF1BAC3ADBE4C3084" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_d0d481f0-55e7-c97c-ec8d-df7b34e55256" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInTwoYears_FC3226A626870ADDF1BAC3ADBE4C3084" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_d0d481f0-55e7-c97c-ec8d-df7b34e55256" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_96758b91-3e32-7021-71f0-7f00c6f170b8" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInTwoYears_FC3226A626870ADDF1BAC3ADBE4C3084" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_96758b91-3e32-7021-71f0-7f00c6f170b8" xlink:type="arc" />
    <loc xlink:href="astm-20150930.xsd#astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInThreeYears_32A4AF2846EC47AAA1C2C3AE78CBE1B8" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDue_64F7D370D9A1CB3630D0C3AC9DFD90E3" xlink:to="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInThreeYears_32A4AF2846EC47AAA1C2C3AE78CBE1B8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_b90d3e1a-4d8a-a6c8-154e-2ac9658c1ba3" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInThreeYears_32A4AF2846EC47AAA1C2C3AE78CBE1B8" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_b90d3e1a-4d8a-a6c8-154e-2ac9658c1ba3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears_c6c61bdb-7d40-5aa5-ee14-dd7f97a8f4fc" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInThreeYears_32A4AF2846EC47AAA1C2C3AE78CBE1B8" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears_c6c61bdb-7d40-5aa5-ee14-dd7f97a8f4fc" xlink:type="arc" />
    <loc xlink:href="astm-20150930.xsd#astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInFourYears_C601124C56105A67225FC3AF5595FAF2" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDue_64F7D370D9A1CB3630D0C3AC9DFD90E3" xlink:to="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInFourYears_C601124C56105A67225FC3AF5595FAF2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_50b4cfc1-5417-1ddf-07f2-e739d063c669" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInFourYears_C601124C56105A67225FC3AF5595FAF2" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_50b4cfc1-5417-1ddf-07f2-e739d063c669" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears_013e722d-3ffa-873f-3749-9676612475c5" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueInFourYears_C601124C56105A67225FC3AF5595FAF2" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears_013e722d-3ffa-873f-3749-9676612475c5" xlink:type="arc" />
    <loc xlink:href="astm-20150930.xsd#astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueThereafter" xlink:label="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueThereafter_AAE3ECE47B5E2A38F35CC3B0559A79F6" xlink:type="locator" />
    <calculationArc order="5" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDue_64F7D370D9A1CB3630D0C3AC9DFD90E3" xlink:to="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueThereafter_AAE3ECE47B5E2A38F35CC3B0559A79F6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_ff03b31f-ab4a-63f9-1de9-6e9385f8247b" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueThereafter_AAE3ECE47B5E2A38F35CC3B0559A79F6" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_ff03b31f-ab4a-63f9-1de9-6e9385f8247b" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueThereafter" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueThereafter_99234088-e8d2-1a50-75c0-3f705ebaaccd" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDueThereafter_AAE3ECE47B5E2A38F35CC3B0559A79F6" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueThereafter_99234088-e8d2-1a50-75c0-3f705ebaaccd" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDue" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_c4caf5d5-78a3-6d34-8149-1cb46b32bec9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_c4caf5d5-78a3-6d34-8149-1cb46b32bec9" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsRemainderOfFiscalYear_ee012fec-4307-1377-a21d-5433a513d0c2" xlink:type="arc" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_c4caf5d5-78a3-6d34-8149-1cb46b32bec9" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_96758b91-3e32-7021-71f0-7f00c6f170b8" xlink:type="arc" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_c4caf5d5-78a3-6d34-8149-1cb46b32bec9" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears_c6c61bdb-7d40-5aa5-ee14-dd7f97a8f4fc" xlink:type="arc" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_c4caf5d5-78a3-6d34-8149-1cb46b32bec9" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears_013e722d-3ffa-873f-3749-9676612475c5" xlink:type="arc" />
    <calculationArc order="5" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_c4caf5d5-78a3-6d34-8149-1cb46b32bec9" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueThereafter_99234088-e8d2-1a50-75c0-3f705ebaaccd" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_cc811211-f8d9-2df0-b015-05419b9bfc99" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_cc811211-f8d9-2df0-b015-05419b9bfc99" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsRemainderOfFiscalYear_82703f3f-08db-c6b2-481a-9c81c1d5c009" xlink:type="arc" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_cc811211-f8d9-2df0-b015-05419b9bfc99" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_d0d481f0-55e7-c97c-ec8d-df7b34e55256" xlink:type="arc" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_cc811211-f8d9-2df0-b015-05419b9bfc99" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_b90d3e1a-4d8a-a6c8-154e-2ac9658c1ba3" xlink:type="arc" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_cc811211-f8d9-2df0-b015-05419b9bfc99" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_50b4cfc1-5417-1ddf-07f2-e739d063c669" xlink:type="arc" />
    <calculationArc order="5" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_cc811211-f8d9-2df0-b015-05419b9bfc99" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_ff03b31f-ab4a-63f9-1de9-6e9385f8247b" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://vcel.com/role/CommitmentsAndContingenciesDetailsCalc2" xlink:type="extended">
    <loc xlink:href="astm-20150930.xsd#astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDue" xlink:label="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDue_521B9C031C339C5E0E95EE45EFE5314B_64F7D370D9A1CB3630D0C3AC9DFD90E3" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_521B9C031C339C5E0E95EE45EFE5314B_cc811211-f8d9-2df0-b015-05419b9bfc99" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDue_521B9C031C339C5E0E95EE45EFE5314B_64F7D370D9A1CB3630D0C3AC9DFD90E3" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_521B9C031C339C5E0E95EE45EFE5314B_cc811211-f8d9-2df0-b015-05419b9bfc99" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDue" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_521B9C031C339C5E0E95EE45EFE5314B_c4caf5d5-78a3-6d34-8149-1cb46b32bec9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_astm_OperatingAndCapitalLeasesFutureMinimumPaymentsDue_521B9C031C339C5E0E95EE45EFE5314B_64F7D370D9A1CB3630D0C3AC9DFD90E3" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_521B9C031C339C5E0E95EE45EFE5314B_c4caf5d5-78a3-6d34-8149-1cb46b32bec9" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://vcel.com/role/CommitmentsAndContingenciesTables" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/ConcentrationOfCreditRisk" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/ConcentrationOfCreditRiskDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/CondensedConsolidatedBalanceSheets" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_b517a4f1-4597-b094-2608-75af660328e1" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_67f49e84-05fd-4b0b-ae5a-e9913b97cea2" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_b517a4f1-4597-b094-2608-75af660328e1" xlink:to="loc_us-gaap_AssetsCurrent_67f49e84-05fd-4b0b-ae5a-e9913b97cea2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_Cash" xlink:label="loc_us-gaap_Cash_ed1351d7-08ed-47ff-642b-430da354f5e2" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_67f49e84-05fd-4b0b-ae5a-e9913b97cea2" xlink:to="loc_us-gaap_Cash_ed1351d7-08ed-47ff-642b-430da354f5e2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_dc301a2a-78b3-2f7c-72b2-6d5ec18f9327" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_67f49e84-05fd-4b0b-ae5a-e9913b97cea2" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_dc301a2a-78b3-2f7c-72b2-6d5ec18f9327" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_a00a52e0-8d97-7156-7079-2c628ca1666f" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_67f49e84-05fd-4b0b-ae5a-e9913b97cea2" xlink:to="loc_us-gaap_InventoryNet_a00a52e0-8d97-7156-7079-2c628ca1666f" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OtherAssetsCurrent" xlink:label="loc_us-gaap_OtherAssetsCurrent_14f3514d-b887-3e26-e467-f2a9d9f3f19e" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_67f49e84-05fd-4b0b-ae5a-e9913b97cea2" xlink:to="loc_us-gaap_OtherAssetsCurrent_14f3514d-b887-3e26-e467-f2a9d9f3f19e" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_a1eaafaf-055b-e423-85ef-4424fb2ef4e4" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_b517a4f1-4597-b094-2608-75af660328e1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_a1eaafaf-055b-e423-85ef-4424fb2ef4e4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_32ecd7de-6410-d56f-5547-ab1b682ebbc0" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_b517a4f1-4597-b094-2608-75af660328e1" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_32ecd7de-6410-d56f-5547-ab1b682ebbc0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_ae9fd5e7-8741-dfbd-241e-1460ec6c786e" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_16ce0436-3b82-55c5-d896-5cba4c9023bd" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_ae9fd5e7-8741-dfbd-241e-1460ec6c786e" xlink:to="loc_us-gaap_Liabilities_16ce0436-3b82-55c5-d896-5cba4c9023bd" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_1477e02d-b6d8-3df6-e715-8364fedce6d9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_16ce0436-3b82-55c5-d896-5cba4c9023bd" xlink:to="loc_us-gaap_LiabilitiesCurrent_1477e02d-b6d8-3df6-e715-8364fedce6d9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_bd7b63fa-09ae-1100-16fe-5ac027208548" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_1477e02d-b6d8-3df6-e715-8364fedce6d9" xlink:to="loc_us-gaap_AccountsPayableCurrent_bd7b63fa-09ae-1100-16fe-5ac027208548" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_771fda46-ad18-43f7-74a8-24b4258a1976" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_1477e02d-b6d8-3df6-e715-8364fedce6d9" xlink:to="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_771fda46-ad18-43f7-74a8-24b4258a1976" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_WarrantsAndRightsOutstanding" xlink:label="loc_us-gaap_WarrantsAndRightsOutstanding_ce979c60-36c9-c8c1-cd3c-341cd1a8c7d0" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_1477e02d-b6d8-3df6-e715-8364fedce6d9" xlink:to="loc_us-gaap_WarrantsAndRightsOutstanding_ce979c60-36c9-c8c1-cd3c-341cd1a8c7d0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OtherLiabilitiesCurrent" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_80fb613f-3ffa-40b4-21a0-ecd4148b8f5c" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_1477e02d-b6d8-3df6-e715-8364fedce6d9" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_80fb613f-3ffa-40b4-21a0-ecd4148b8f5c" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_89b83a57-ffbc-fc48-170d-f8b25d163e54" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_16ce0436-3b82-55c5-d896-5cba4c9023bd" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_89b83a57-ffbc-fc48-170d-f8b25d163e54" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_f7fce5cd-2d53-a8b3-a485-6d0f3635b8fe" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_16ce0436-3b82-55c5-d896-5cba4c9023bd" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_f7fce5cd-2d53-a8b3-a485-6d0f3635b8fe" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_26e56c7a-24ab-e869-809a-0509ccbe86d9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_ae9fd5e7-8741-dfbd-241e-1460ec6c786e" xlink:to="loc_us-gaap_StockholdersEquity_26e56c7a-24ab-e869-809a-0509ccbe86d9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PreferredStockValueOutstanding" xlink:label="loc_us-gaap_PreferredStockValueOutstanding_e72fe7b3-c6f0-6b01-18f8-4ad3bbc40c93" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_26e56c7a-24ab-e869-809a-0509ccbe86d9" xlink:to="loc_us-gaap_PreferredStockValueOutstanding_e72fe7b3-c6f0-6b01-18f8-4ad3bbc40c93" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaap_CommonStockValue_ffd09989-75a8-4713-beb0-21bebb3561d6" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_26e56c7a-24ab-e869-809a-0509ccbe86d9" xlink:to="loc_us-gaap_CommonStockValue_ffd09989-75a8-4713-beb0-21bebb3561d6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_4d60b95b-a2a9-55da-7eaa-2ca718a58484" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_26e56c7a-24ab-e869-809a-0509ccbe86d9" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_4d60b95b-a2a9-55da-7eaa-2ca718a58484" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DevelopmentStageEnterpriseDeficitAccumulatedDuringDevelopmentStage" xlink:label="loc_us-gaap_DevelopmentStageEnterpriseDeficitAccumulatedDuringDevelopmentStage_ac3d21e7-dbe4-36d7-7853-6e6ce90d9491" xlink:type="locator" />
    <calculationArc order="4" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_26e56c7a-24ab-e869-809a-0509ccbe86d9" xlink:to="loc_us-gaap_DevelopmentStageEnterpriseDeficitAccumulatedDuringDevelopmentStage_ac3d21e7-dbe4-36d7-7853-6e6ce90d9491" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_a7bb915d-e645-20d7-7b2e-623731454f45" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_ae9fd5e7-8741-dfbd-241e-1460ec6c786e" xlink:to="loc_us-gaap_CommitmentsAndContingencies_a7bb915d-e645-20d7-7b2e-623731454f45" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://vcel.com/role/CondensedConsolidatedBalanceSheetsParenthetical" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/CondensedConsolidatedStatementsOfCashFlows" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetCashProvidedByUsedInContinuingOperations" xlink:label="loc_us-gaap_NetCashProvidedByUsedInContinuingOperations_1b44c970-9641-7e6c-3ec0-bdb66c161a80" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInContinuingOperations_1b44c970-9641-7e6c-3ec0-bdb66c161a80" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_faecc408-4bea-6e13-83bd-71b4c2ddf64c" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_NetIncomeLoss_faecc408-4bea-6e13-83bd-71b4c2ddf64c" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_76f611bf-6cac-2837-6d7c-3028d488fc3b" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_76f611bf-6cac-2837-6d7c-3028d488fc3b" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_aa7a0bc5-86c6-13a8-3676-9960bad8007f" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_ShareBasedCompensation_aa7a0bc5-86c6-13a8-3676-9960bad8007f" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FairValueAdjustmentOfWarrants" xlink:label="loc_us-gaap_FairValueAdjustmentOfWarrants_c9874c1d-14ea-cf90-f9b8-3a1b6b1b19e2" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_FairValueAdjustmentOfWarrants_c9874c1d-14ea-cf90-f9b8-3a1b6b1b19e2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AssetRetirementObligationLiabilitiesSettled" xlink:label="loc_us-gaap_AssetRetirementObligationLiabilitiesSettled_e6f2850d-dee5-3913-d9d1-09d21cd01723" xlink:type="locator" />
    <calculationArc order="5" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_AssetRetirementObligationLiabilitiesSettled_e6f2850d-dee5-3913-d9d1-09d21cd01723" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InventoryWriteDown" xlink:label="loc_us-gaap_InventoryWriteDown_2ced02ad-9655-9408-a10b-884e42903c1c" xlink:type="locator" />
    <calculationArc order="6" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_InventoryWriteDown_2ced02ad-9655-9408-a10b-884e42903c1c" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_BusinessCombinationBargainPurchaseGainRecognizedAmount" xlink:label="loc_us-gaap_BusinessCombinationBargainPurchaseGainRecognizedAmount_5f8b336f-69e8-356f-6208-d4134c2fd3eb" xlink:type="locator" />
    <calculationArc order="7" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_BusinessCombinationBargainPurchaseGainRecognizedAmount_5f8b336f-69e8-356f-6208-d4134c2fd3eb" xlink:type="arc" />
    <loc xlink:href="astm-20150930.xsd#astm_ForeignCurrencyTranslationGain" xlink:label="loc_astm_ForeignCurrencyTranslationGain_02CE5148C737F621AB17188742E8FFA2" xlink:type="locator" />
    <calculationArc order="8" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_astm_ForeignCurrencyTranslationGain_02CE5148C737F621AB17188742E8FFA2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_GainLossOnDispositionOfAssets" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets_2ce8accf-e09c-efa1-9d09-9b291f4dca51" xlink:type="locator" />
    <calculationArc order="9" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets_2ce8accf-e09c-efa1-9d09-9b291f4dca51" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_d2a8fa0f-43df-513c-7a7b-93e04034bb1e" xlink:type="locator" />
    <calculationArc order="10" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_d2a8fa0f-43df-513c-7a7b-93e04034bb1e" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInReceivables" xlink:label="loc_us-gaap_IncreaseDecreaseInReceivables_b7b4b1a7-b864-5660-8468-21c7409fee96" xlink:type="locator" />
    <calculationArc order="11" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_IncreaseDecreaseInReceivables_b7b4b1a7-b864-5660-8468-21c7409fee96" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInOtherCurrentAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherCurrentAssets_e8d4ae79-a40a-c59b-cfc8-5b339045a986" xlink:type="locator" />
    <calculationArc order="12" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherCurrentAssets_e8d4ae79-a40a-c59b-cfc8-5b339045a986" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_af8dcf28-5bbb-ce71-1ed2-41689425cc96" xlink:type="locator" />
    <calculationArc order="13" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_af8dcf28-5bbb-ce71-1ed2-41689425cc96" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_81d33709-3a03-d961-0ad3-fd439ce3c40d" xlink:type="locator" />
    <calculationArc order="14" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_81d33709-3a03-d961-0ad3-fd439ce3c40d" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_1cad8493-0a39-874e-a6b0-6d35514a892c" xlink:type="locator" />
    <calculationArc order="15" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_1cad8493-0a39-874e-a6b0-6d35514a892c" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInRestructuringReserve" xlink:label="loc_us-gaap_IncreaseDecreaseInRestructuringReserve_d6853056-dbde-ded2-6b57-4a74ed1d59b7" xlink:type="locator" />
    <calculationArc order="16" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_IncreaseDecreaseInRestructuringReserve_d6853056-dbde-ded2-6b57-4a74ed1d59b7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_b8c20b3a-3bcf-0736-e626-15ffaf302374" xlink:type="locator" />
    <calculationArc order="17" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_32645c9d-8ff4-9939-6e7f-1f133b2a6c08" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_b8c20b3a-3bcf-0736-e626-15ffaf302374" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_f47d1996-b77d-36f7-28c4-5d2058bf9b25" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInContinuingOperations_1b44c970-9641-7e6c-3ec0-bdb66c161a80" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_f47d1996-b77d-36f7-28c4-5d2058bf9b25" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_d07148ef-7d32-9c78-2111-e77f98145cb0" xlink:type="locator" />
    <calculationArc order="1" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_f47d1996-b77d-36f7-28c4-5d2058bf9b25" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_d07148ef-7d32-9c78-2111-e77f98145cb0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PaymentsForProceedsFromOtherInvestingActivities" xlink:label="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_b8d3719c-373d-7569-4a73-17b00d7e541c" xlink:type="locator" />
    <calculationArc order="2" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_f47d1996-b77d-36f7-28c4-5d2058bf9b25" xlink:to="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_b8d3719c-373d-7569-4a73-17b00d7e541c" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_37181af6-e562-cefc-f2b6-8490ea2c3e04" xlink:type="locator" />
    <calculationArc order="3" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_f47d1996-b77d-36f7-28c4-5d2058bf9b25" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_37181af6-e562-cefc-f2b6-8490ea2c3e04" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_7f6f8cbc-c7f0-15c2-432d-caa740b32a35" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInContinuingOperations_1b44c970-9641-7e6c-3ec0-bdb66c161a80" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_7f6f8cbc-c7f0-15c2-432d-caa740b32a35" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ProceedsFromIssuanceOfPreferredStockAndPreferenceStock" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfPreferredStockAndPreferenceStock_b1cbc05f-4cef-59db-24cb-549d342d8f23" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_7f6f8cbc-c7f0-15c2-432d-caa740b32a35" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfPreferredStockAndPreferenceStock_b1cbc05f-4cef-59db-24cb-549d342d8f23" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RepaymentsOfDebt" xlink:label="loc_us-gaap_RepaymentsOfDebt_a09b8b17-dfd0-6f65-bc95-ce08e5c4af2c" xlink:type="locator" />
    <calculationArc order="2" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_7f6f8cbc-c7f0-15c2-432d-caa740b32a35" xlink:to="loc_us-gaap_RepaymentsOfDebt_a09b8b17-dfd0-6f65-bc95-ce08e5c4af2c" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_21149c4c-60e9-1f3a-82d3-665a83a5c4f2" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInContinuingOperations_1b44c970-9641-7e6c-3ec0-bdb66c161a80" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_21149c4c-60e9-1f3a-82d3-665a83a5c4f2" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://vcel.com/role/CondensedConsolidatedStatementsOfComprehensiveLoss" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_375e0d17-4818-4239-a370-aada0b6ca8eb" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_faecc408-4bea-6e13-83bd-71b4c2ddf64c" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_375e0d17-4818-4239-a370-aada0b6ca8eb" xlink:to="loc_us-gaap_NetIncomeLoss_faecc408-4bea-6e13-83bd-71b4c2ddf64c" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_f949b2e8-d740-7c2b-d949-74ff04888c67" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_375e0d17-4818-4239-a370-aada0b6ca8eb" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_f949b2e8-d740-7c2b-d949-74ff04888c67" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://vcel.com/role/CondensedConsolidatedStatementsOfOperations" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_faecc408-4bea-6e13-83bd-71b4c2ddf64c" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_72b2c986-6e1a-bdde-cc72-888b0df562b9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_faecc408-4bea-6e13-83bd-71b4c2ddf64c" xlink:to="loc_us-gaap_OperatingIncomeLoss_72b2c986-6e1a-bdde-cc72-888b0df562b9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_77a77c8a-8a13-919c-6d50-d35f60384ab0" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_72b2c986-6e1a-bdde-cc72-888b0df562b9" xlink:to="loc_us-gaap_GrossProfit_77a77c8a-8a13-919c-6d50-d35f60384ab0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="loc_us-gaap_CostOfGoodsSold_f60bb493-e4bb-89cc-3640-4febfc5d9f27" xlink:type="locator" />
    <calculationArc order="1" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_77a77c8a-8a13-919c-6d50-d35f60384ab0" xlink:to="loc_us-gaap_CostOfGoodsSold_f60bb493-e4bb-89cc-3640-4febfc5d9f27" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SalesRevenueNet" xlink:label="loc_us-gaap_SalesRevenueNet_0863786b-6bf9-966f-db7b-d5636f830397" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_77a77c8a-8a13-919c-6d50-d35f60384ab0" xlink:to="loc_us-gaap_SalesRevenueNet_0863786b-6bf9-966f-db7b-d5636f830397" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:label="loc_us-gaap_SalesRevenueGoodsNet_407dba67-ed61-44c5-d72f-b6457c9a2967" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_SalesRevenueNet_0863786b-6bf9-966f-db7b-d5636f830397" xlink:to="loc_us-gaap_SalesRevenueGoodsNet_407dba67-ed61-44c5-d72f-b6457c9a2967" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaap_OperatingExpenses_ee2bd36d-150a-7303-38c4-eb755f792210" xlink:type="locator" />
    <calculationArc order="2" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_72b2c986-6e1a-bdde-cc72-888b0df562b9" xlink:to="loc_us-gaap_OperatingExpenses_ee2bd36d-150a-7303-38c4-eb755f792210" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_7d1bc05d-33ee-c009-4533-b70ee0a74dc9" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_ee2bd36d-150a-7303-38c4-eb755f792210" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_7d1bc05d-33ee-c009-4533-b70ee0a74dc9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_581512af-7ae6-1b38-5ef5-f123bd81ccb9" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_ee2bd36d-150a-7303-38c4-eb755f792210" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_581512af-7ae6-1b38-5ef5-f123bd81ccb9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_89191b30-59c9-0ba0-34ea-6e2a98cbdb1c" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_faecc408-4bea-6e13-83bd-71b4c2ddf64c" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_89191b30-59c9-0ba0-34ea-6e2a98cbdb1c" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FairValueAdjustmentOfWarrants" xlink:label="loc_us-gaap_FairValueAdjustmentOfWarrants_c9874c1d-14ea-cf90-f9b8-3a1b6b1b19e2" xlink:type="locator" />
    <calculationArc order="1" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_89191b30-59c9-0ba0-34ea-6e2a98cbdb1c" xlink:to="loc_us-gaap_FairValueAdjustmentOfWarrants_c9874c1d-14ea-cf90-f9b8-3a1b6b1b19e2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_BusinessCombinationBargainPurchaseGainRecognizedAmount" xlink:label="loc_us-gaap_BusinessCombinationBargainPurchaseGainRecognizedAmount_5f8b336f-69e8-356f-6208-d4134c2fd3eb" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_89191b30-59c9-0ba0-34ea-6e2a98cbdb1c" xlink:to="loc_us-gaap_BusinessCombinationBargainPurchaseGainRecognizedAmount_5f8b336f-69e8-356f-6208-d4134c2fd3eb" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ForeignCurrencyTransactionGainLossRealized" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossRealized_5ea5b4ec-eaf4-c267-d9ff-fd8876405cd2" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_89191b30-59c9-0ba0-34ea-6e2a98cbdb1c" xlink:to="loc_us-gaap_ForeignCurrencyTransactionGainLossRealized_5ea5b4ec-eaf4-c267-d9ff-fd8876405cd2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="loc_us-gaap_InvestmentIncomeInterest_a24d82ba-62b0-7744-0b3a-f37dbe668bee" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_89191b30-59c9-0ba0-34ea-6e2a98cbdb1c" xlink:to="loc_us-gaap_InvestmentIncomeInterest_a24d82ba-62b0-7744-0b3a-f37dbe668bee" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_cefe1779-647b-11ee-28a9-2740d86c056b" xlink:type="locator" />
    <calculationArc order="5" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_89191b30-59c9-0ba0-34ea-6e2a98cbdb1c" xlink:to="loc_us-gaap_InterestExpense_cefe1779-647b-11ee-28a9-2740d86c056b" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://vcel.com/role/DocumentAndEntityInformation" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/FairValueMeasurements" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/FairValueMeasurementsLevel3InputsDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/FairValueMeasurementsRecurringBasisDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/FairValueMeasurementsTables" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/NetLossPerCommonShare" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/NetLossPerCommonShareDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_26d32ed1-5af3-4218-f177-31c9b3d51d7f" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_faecc408-4bea-6e13-83bd-71b4c2ddf64c" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_26d32ed1-5af3-4218-f177-31c9b3d51d7f" xlink:to="loc_us-gaap_NetIncomeLoss_faecc408-4bea-6e13-83bd-71b4c2ddf64c" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PreferredStockDividendsIncomeStatementImpact" xlink:label="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_462424c6-386a-c74c-dc6d-82040ccbf9e0" xlink:type="locator" />
    <calculationArc order="2" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_26d32ed1-5af3-4218-f177-31c9b3d51d7f" xlink:to="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_462424c6-386a-c74c-dc6d-82040ccbf9e0" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://vcel.com/role/NetLossPerCommonShareTables" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/Organization" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/OrganizationDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/PreferredStock" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/PreferredStockDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/RecentAccountingPronouncements" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/RecentAccountingPronouncementsPolicies" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/Restructuring" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/RestructuringDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/SelectedBalanceSheetComponents" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/SelectedBalanceSheetComponentsAccruedExpensesDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_771fda46-ad18-43f7-74a8-24b4258a1976" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccruedBonusesCurrentAndNoncurrent" xlink:label="loc_us-gaap_AccruedBonusesCurrentAndNoncurrent_b6d8c03b-949b-780d-76f2-c7c59aa25767" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_771fda46-ad18-43f7-74a8-24b4258a1976" xlink:to="loc_us-gaap_AccruedBonusesCurrentAndNoncurrent_b6d8c03b-949b-780d-76f2-c7c59aa25767" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_d69c5cc5-fc70-31a7-c2b1-924eb363b75b" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_771fda46-ad18-43f7-74a8-24b4258a1976" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_d69c5cc5-fc70-31a7-c2b1-924eb363b75b" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_1d834322-984c-3ee2-a4a0-2dc90b007763" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_771fda46-ad18-43f7-74a8-24b4258a1976" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_1d834322-984c-3ee2-a4a0-2dc90b007763" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AssetRetirementObligationCurrent" xlink:label="loc_us-gaap_AssetRetirementObligationCurrent_2a1ec59b-1953-19e8-7ed8-2af7ed3bcdac" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_771fda46-ad18-43f7-74a8-24b4258a1976" xlink:to="loc_us-gaap_AssetRetirementObligationCurrent_2a1ec59b-1953-19e8-7ed8-2af7ed3bcdac" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OtherAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent_46c5e103-584b-b600-2852-4201435cc29f" xlink:type="locator" />
    <calculationArc order="5" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_771fda46-ad18-43f7-74a8-24b4258a1976" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrent_46c5e103-584b-b600-2852-4201435cc29f" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://vcel.com/role/SelectedBalanceSheetComponentsIntangibleAssetsDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_e5eebb39-2b5a-2098-5917-f925f42760f7" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_42b85d66-347c-1d04-e532-6585df9e0ef3" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet_e5eebb39-2b5a-2098-5917-f925f42760f7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_42b85d66-347c-1d04-e532-6585df9e0ef3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_283368b3-486d-3829-d3e1-812e3b2045be" xlink:type="locator" />
    <calculationArc order="2" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet_e5eebb39-2b5a-2098-5917-f925f42760f7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_283368b3-486d-3829-d3e1-812e3b2045be" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_f758eeab-188e-eaee-e99b-265cced6ca31" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet_e5eebb39-2b5a-2098-5917-f925f42760f7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_f758eeab-188e-eaee-e99b-265cced6ca31" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_39b73fc1-068f-1f24-eb8a-6bd6e66228a7" xlink:type="locator" />
    <calculationArc order="4" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet_e5eebb39-2b5a-2098-5917-f925f42760f7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_39b73fc1-068f-1f24-eb8a-6bd6e66228a7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_75d6e205-51a2-df5c-8716-074fd2fa97ea" xlink:type="locator" />
    <calculationArc order="5" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet_e5eebb39-2b5a-2098-5917-f925f42760f7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_75d6e205-51a2-df5c-8716-074fd2fa97ea" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_34afc9e8-20b4-4de9-2358-e1151abfab69" xlink:type="locator" />
    <calculationArc order="6" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet_e5eebb39-2b5a-2098-5917-f925f42760f7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_34afc9e8-20b4-4de9-2358-e1151abfab69" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_3fe538bc-8021-86e4-382f-d1e92244d92f" xlink:type="locator" />
    <calculationArc order="7" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet_e5eebb39-2b5a-2098-5917-f925f42760f7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_3fe538bc-8021-86e4-382f-d1e92244d92f" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_8d1e5420-7495-1a55-8fee-b3d5bf5e19ca" xlink:type="locator" />
    <calculationArc order="8" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNet_e5eebb39-2b5a-2098-5917-f925f42760f7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_8d1e5420-7495-1a55-8fee-b3d5bf5e19ca" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://vcel.com/role/SelectedBalanceSheetComponentsInventoryDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_a00a52e0-8d97-7156-7079-2c628ca1666f" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InventoryRawMaterials" xlink:label="loc_us-gaap_InventoryRawMaterials_ca5675fa-3669-0508-f8f8-c458a305105a" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_a00a52e0-8d97-7156-7079-2c628ca1666f" xlink:to="loc_us-gaap_InventoryRawMaterials_ca5675fa-3669-0508-f8f8-c458a305105a" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InventoryWorkInProcess" xlink:label="loc_us-gaap_InventoryWorkInProcess_dd600383-7de1-3e0d-0e97-d93b54365aa1" xlink:type="locator" />
    <calculationArc order="2" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_a00a52e0-8d97-7156-7079-2c628ca1666f" xlink:to="loc_us-gaap_InventoryWorkInProcess_dd600383-7de1-3e0d-0e97-d93b54365aa1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InventoryFinishedGoods" xlink:label="loc_us-gaap_InventoryFinishedGoods_a7a72293-99f2-9a8c-faf4-5598ab4577d7" xlink:type="locator" />
    <calculationArc order="3" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_InventoryNet_a00a52e0-8d97-7156-7079-2c628ca1666f" xlink:to="loc_us-gaap_InventoryFinishedGoods_a7a72293-99f2-9a8c-faf4-5598ab4577d7" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://vcel.com/role/SelectedBalanceSheetComponentsPropertyPlantAndEquipmentDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_a1eaafaf-055b-e423-85ef-4424fb2ef4e4" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_c4121e9a-097d-7136-dbac-b93469330286" xlink:type="locator" />
    <calculationArc order="1" weight="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_a1eaafaf-055b-e423-85ef-4424fb2ef4e4" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_c4121e9a-097d-7136-dbac-b93469330286" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_2c0591e3-817a-5563-df1e-5c3ede33266d" xlink:type="locator" />
    <calculationArc order="2" weight="-1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_a1eaafaf-055b-e423-85ef-4424fb2ef4e4" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_2c0591e3-817a-5563-df1e-5c3ede33266d" xlink:type="arc" />
  </calculationLink>
  <calculationLink xlink:role="http://vcel.com/role/SelectedBalanceSheetComponentsTables" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/ShareholdersEquity" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/ShareholdersEquityDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/StockBasedCompensation" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/StockBasedCompensationDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/StockBasedCompensationTables" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/StockPurchaseWarrants" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/StockPurchaseWarrantsDetails" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/StockPurchaseWarrantsTables" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/SubsequentEvents" xlink:type="extended" />
  <calculationLink xlink:role="http://vcel.com/role/SubsequentEventsDetails" xlink:type="extended" />
</linkbase>





