CHARACTERIZATION OF THE REPAIR TISSUE IN ARTICULAR-CARTILAGE DEFECTS USING SILVER-ENHANCED COLLOIDAL GOLD IMMUNOSTAINING

The newly developed silver-enhanced colloidal gold staining method was used in a rabbit model to characterize the repair tissue in large art icular cartilage defects filled with a heterocyclic methacrylate polym er. By 6 weeks the resurfacing tissue consisted of highly organized hy aline-like articular cartilage, fully integrated with the adjacent nor mal cartilage. Immuno-histochemistry detected collagen type II, kerata n sulphate, chondroitin 4-sulphate and chondroitin 6-sulphate in the m atrix of the neocartilage. The level to which the polymer plug was rec essed appeared to be critical to the overall quality of the repair tis sue. Optimum results were obtained when the top surface of the biomate rial was at the level of the subchondral bone, below the level of the surrounding articular cartilage. Other technical aspects of implantati on, that also affect the repair, are also discussed.