A new application of demineralised bone as a tendon graft

• Main Author: Elnikety, S.
• Published: University College London (University of London) 2015
• Subjects: 617.4
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.679933

Tendon injuries present a challenging situation for orthopaedic surgeons. In severe injuries, a tendon transfer or a tendon graft is usually used. The aim is to find a biocompatible substance with mechanical and structural properties that replicate those of normal tendon. Because of its structural and mechanical properties, we propose that Demineralised Cortical Bone (DCB) can be used in the repair of tendon and ligament, as well as for the regeneration of the enthesis. I hypothesise that DCB grafted in a tendon environment will result in remodelling of the DCB into tendon and produce a fibrocartilaginous enthesis. DCB was prepared according to a modified Urist technique and the effect of gamma irradiation and/or freeze-drying on the tensile strength of the DCB was examined. In the second part of the study, four models of repair of a patellar tendon defect were examined for their strength to failure in order to identify a suitable technique for an in vivo animal model. In the final part of the study, a preclinical animal study was performed using DCB as a tendon graft to treat defect in sheep patellar tendon. Animals were allowed to mobilise immediately post-operatively and were sacrificed after 12 weeks. Force plate analyses, X-ray Radiographs, pQCT scans and histological analyses were performed. My results show that DCB remodelled into a ligament-like structure with evidence of neo-enthesis. No evidence of ossification; instead, DCB retrieved was cellularised and vascularised with evidence of crimp and integration into the patellar tendon. My results prove that DCB can be used as a biological tendon graft; this new application of demineralised bone has the potential for solving one of the most challenging injuries. Combined with the correct surgical techniques, early mobilization can be achieved, which results in the remodelling of the DCB into a normal tendon structure.