Re-attachment of tendon to bone is challenging with surgical repair failing in up to 90% of cases. Poor biological healing is common and characterised by the formation of weak scar tissue. Previous work has demonstrated that decellularised allogenic demineralised bone matrix (DBM) regenerates a physiologic enthesis. Xenografts offer a more cost-effective option but concerns over their immunogenicity have been raised. We hypothesised that augmentation of a healing tendon-bone interface with DBM incorporated with autologous mesenchymal stem cells (MSCs) would result in improved function, and restoration of the native enthesis, with no difference between xenogenic and allogenic scaffolds. Using an ovine model of tendon-bone retraction the patellar tendon was detached and a complete distal tendon defect measuring 1 cm was created. Suture anchors were used to reattach the shortened tendon and xenogenic DBM + MSCs (n=5) and allogenic DBM + MSCs (n=5) were used to bridge the defect. Functional recovery was assessed every 3 weeks and DBM incorporation into the tendon and its effect on enthesis regeneration was measured using histomorphometry.Background
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