USE OF POROUS POLYURETHANES FOR MENISCAL RECONSTRUCTION AND MENISCAL PROSTHESES

In the past, porous materials made of an aromatic polyurethane (PU) we re successfully used for meniscal reconstruction in dogs. Since aromat ic PUs yield very toxic fragments upon degradation, a linear PU was sy nthesized by curing a poly(epsilon-caprolactone) and 1,4-trans-cyclohe xane diisocyanate I based prepolymer with cyclohexanedimethanol. Porou s materials of this polymer were also implanted for meniscal reconstru ction. The results were comparable with the most successful implant se ries so far. Additionally, a porous meniscal prosthesis was developed to replace a total meniscus. Due to the very high shear stresses to wh ich the prosthesis would be exposed, the stress hysteresis phenomenon linear PUs are known to exhibit could be of great consequence. Therefo re an aliphatic PU network, synthesized by cross-linking poly(epsilon- caprolactone) and 1,4-trans-cyclohexane diisocyanate with glycerol, wa s used. Dislocation caused by tearing out of the sutures was found to be a problem because the tear resistance of the material was relativel y low. In this study the tearing problem has been partly circumvented by using a complex suturing technique. Meniscal prostheses turned out to induce fibrocartilage upon implantation, and degeneration of articu lar cartilage was less severe than after meniscectomy.