ABSTRACT
AIM: The purpose of this study was to evaluate the biomechanical quality of cartilage and repair tissue in a sheep's knee. 4 standardized 7 mm defects were created on the medial femoral condyle and on the patellar groove (n = 22). These were treated with 4 different cartilage repair procedures and examined 1 year later. MATERIAL AND METHODS: The different groups were: (1) a cell-seeded collagen type-I/III-membrane (Chondro Gide(R)) glued into the defect; (2) a collagen type-I/III-membrane, sutured and cells injected underneath; (3) an engineered, cell-seeded collagen type-II-membrane, glued; (4) periosteum sutured and cells injected underneath; (5) CONTROLS: healthy contra-lateral knees. Indentation tests were performed to reveal the biomechanical capacity. From creep indentation over 35 s a "25-s creep index" was calculated. A high creep index means that the cartilage can undergo greater and faster compression. RESULTS: The repair tissue was significantly thinner than the normal cartilage. The mean creep index of all repair tissues was measured at 111 and 125, respectively (p < 0.05). There were no significant differences among the treated groups. CONCLUSION: In this animal study, none of the induced repair tissues was biomechanically comparable to genuine articular cartilage.
