A HYDROPHYLIC POLYMER SYSTEM ENHANCED ARTICULAR-CARTILAGE REGENERATION IN-VIVO

This study describes a new method for the repair of large articular ca rtilage defects in the knee joint a nd com pa res the effect of two po lymer systems on the quality of the repair tissue. The two systems are a newly developed hydrophylic system, based on poly-ethylmethacrylate (PEMA) polymer and tetra-hydro-furfuryl-methacrylate (THFMA) monomer and the conventional bone cement polymer system, based on poly-methyl- methacrylate (PMMA) polymer and methyl-methacrylate (MMA) monomer. Thi rty adult Sandy-lop rabbits were used. Both knees were operated on in each animal, the one defect received either PEMA/THFMA or conventional bone cement and the contralateral defect received no biomaterial (con trol group). Femora were retrieved at six weeks and the repair tissue was studied by histology, histochemistry and immuno-histochemistry. PE MA/THFMA enhanced the quality of the repair significantly (p < 0.0001) . By six weeks hyaline-like articular cartilage was the predominant ti ssue covering the defects and it was fully integrated with the surroun ding normal articular cartilage. Immune-localization showed cartilage components, including collagen type II, distributed evenly throughout its matrix. PMMA/MMA on the other hand did not improve significantly t he repair tissue, which was predominately fibro-cartilaginous, poorly bonded to the adjacent normal articular cartilage. The method of impla ntation is simple and easily reproducible and the new polymer has been well-accepted by the rabbits.