THE REGENERATION OF ARTICULAR-CARTILAGE USING A NEW POLYMER SYSTEM

A polymer system based on room temperature polymerising poly(ethylmeth acrylate) polymer powder and tetrahydrofurfuryl monomer has been inves tigated as a biomaterial for encouraging articular cartilage repair. T his heterocyclic methacrylate polymer system swells slightly in situ a nd thus provides a good interface with subchondral bone resulting in m echanical stability with favourable uptake kinetics. Another feature o f this polymer system is that it exhibits high water uptake which lead s to absorption of the surrounding tissue fluid and matrix proteins, i ncluding growth factors; this may encourage the formation of new carti lage. Three weeks after implantation the tissue overgrowth contained c artilage components: chondrocytes, collagen type II, chondroitin 4-sul phate and chondroitin 6-sulphate. In addition numerous chondrocyte clo nes were observed at the edge of the defect and in the newly repaired tissue. By six weeks a superficial articulating surface was continuous with the normal articular cartilage with underlying tissue which show ed some evidence of endochondral ossification. By nine weeks the surfa ce covering of new cartilage had a widened and an irregular zone of ca lcified cartilage with thickened subchondral bone was present. At eigh t months the resurfaced cartilage remained intact above a remodelled s ubchondral bone end plate.