[Integration of periosteum covered autogenous bone grafts with and without autologous chondrocytes. An animal experiment using the Göttinger minipig].

Autologous osteochondral transplantation has the major disadvantage of significant damage to a healthy joint surface at the donor site. The purpose of this study was to examine the effect of autogenous chondrocytes injected into the periosteum of autologous bone grafts in order to provide an alternative method for cartilage repair. A total of 22 Göttinger minipigs were operated twice on both knees. The first operation served for cartilage biopsy for the chondrocyte culture. During the second operation an osteochondral defect was created in the medial facet of the trochlear groove. The defect was treated differently with an autologous cortico-cancellous bone cylinder,harvested from the proximal tibia.Group A: untreated defect (control);B: bone-graft;C: bone-graft covered with periosteum; D: bone-graft with periosteum and injected autologous chondrocytes. The animals were killed after 6, 12, 26 and 52 weeks. The regenerated areas were evaluated macroscopically, tested biomechanically (long-term specimens; indentation-test) and a histological, blind evaluation was carried out according to a semi-quantitative scoring system. The periosteum covered bone cylinders in Groups C and D showed good repair of the bone and cartilage defect. The repaired tissue consisted predominantly of fibrocartilage with the partial formation of hyalin like tissue. The regenerated areas were integrated with the adjacent cartilage and were biomechanically superior when compared with the other groups. The additional injection of chondrocytes did not produce significantly better results. Our findings suggest that the transplantation of periosteum-covered bone cylinders may provide an alternative method for treating chondral and osteochondral defects and can be recommended for filling large donor site defects in joint surgery. The additional transplantation of chondrocytes does not seem to be justified.