NEOCARTILAGE AFTER ARTIFICIAL CARTILAGE REPAIR IN THE RABBIT - HISTOLOGY AND PROTEOGLYCAN FRAGMENTS IN JOINT FLUID

Repair of full-thickness cartilage defects of the rabbit medial femora l condyle with artificial plugs and periosteal grafts was followed for 1 year. The morphological characteristics of the neocartilage after r epair and the concentration of proteoglycan fragments in the joint flu id (CPFF) were evaluated. The CPFF showed only a weak correlation to t he histological score of the neocartilage. Normal cartilage and subcho ndral bone did not develop with any of the repair alternatives. With a Dacron plug, neocartilage formation appeared earlier than with natura l repair and was better than with periosteal grafting. Increased CPFFs were found in all specimens with repair at 3 months, probably reflect ing the remaining effect of surgery. At 6 months, the CPFFs had normal ized to control values. At 1 year, the CPFFs were again similar to tho se at the 3-month evaluation. This was paralleled by a degeneration of the neocartilage. We conclude that Dacron plugs could serve as a scaf fold for neocartilage formation. The CPFF reflected surgical trauma an d late degeneration of neocartilage but did not indicate minor differe nces in quality between cartilage repair techniques, probably because of the limited size of the grafted defect.