Purpose: Joint cartilage repair is one of the most widely studies aspects of orthopedic care. The tissue’s intrinsic capacity to repair degenerative, inflammatory or trauma-induce damage is low. The purpose of this study was to report early results obtained with an allograft using a hybrid biocartilage in the rabbit.

Material and methods: Chondrocytes obtained by successive enzymatic digestion of joint cartilage from the knee joint were implanted via medial arthrotomy into an osteo-cartilaginous knee defect measuring 4 cm in diameter and 3 mm in depth produced by trepanation of the tronchlea. Both knees were operated in six adult New Zealand rabbits. After eight weeks, the animals were assessed clinically then sacrificed. The femoral condyles were removed for histological study. All grafted joints were mobile and had normal function without risk of self-mutilation.

Results: The joint samples did not show any evidence of effusion. The implant site was still visible macroscopically and presented a cartilaginous surface continuous with the healthy cartilage. After HES staining, the distal pole of the implant was found to be colonised with young cartilage continuous with the trochlear cartilage. Enchondral ossification appeared to be present in the distal part of certain cartilaginous nodules with a bony lamina continuous with the adjacent subchondral bone. There was no evidence of an inflammatory reaction of the synovial and the patellar cartilage was normal.

Discussion: These preliminary results of a hybrid biocartilage graft combined with cartilage surface reconstruction and osteointegration of the deep implant without in vivo supply of growth factors are encouraging. The safety of the supporting material was demonstrated. We are currently working on developing an autograft from progenitor cells.