[Autologous transplantation of rib perichondrium in treatment of deep cartilage defects of the knee joint of sheep. Morphologic comparison of two resorbable fixation methods].

The purpose of this study was to examine the fate of autologous perichondrial grafts after transplantation into cartilage lesions in weight-bearing joints, with reference to different fixation methods and different regimens of postoperative functional treatment. Full-thickness osteochondral lesions were drilled in the articular surface of knee joints in 36 sheep. The defects were filled with autologous rib perichondrial grafts, which were secured by either collagen sponges (group A; n = 12 animals) or fibrin glue (group B; n = 12 animals). Defects not filled with perichondrial grafts served as controls (group C; n = 12 animals). Following 1 week of immobilization of the treated leg, the plaster was removed and the animals were allowed to move freely. Animals were sacrificed after 4, 8, 12 and 16 weeks. The grafts were removed and investigated histologically. In contrast to weight-bearing areas and control defects, hyaline-like cartilage formation could be noted in non-weight-bearing areas after 4 weeks. This newly formed cartilage revealed strong metachromasie following staining with acidic toluidine-blue and reacted positively with PAS, indicating de novo synthesis of proteoglycans and glycoproteins. Enzyme-histochemistry for alkaline and acid phosphatase activity showed positive reactivity only at the base of the transplants. Quantitatively, hyalin-like cartilage was achieved in 40/48 transplants from the non-weight-bearing area (20/24 transplants fixated with collagen sponge (group A); and 20/24 fixated with fibrin glue (group B). In control defects only fibrous scar tissue was detectable. In transplants from the weight-bearing area only 7/48 (24 of group A and B each) a differentiation into hyalin-like cartilage was visible.(ABSTRACT TRUNCATED AT 250 WORDS)