MENISCAL TISSUE REGENERATION IN POROUS 50 50 COPOLY(L-LACTIDE/EPSILON-CAPROLACTONE) IMPLANTS/

Porous materials of a high-molecular-weight 50/50 copolymer of L-lacti de and epsilon-caprolactone with different compression moduli were use d for meniscal repair. In contrast to the previously used 4,4'-dipheny lmethane and 1,6-trans-cyclohexane diisocyanates containing polyuretha nes, degradation products of the copolymer are non-toxic. Two series o f porous materials with compression moduli of 40 and 100 kPa respectiv ely were implanted in the knees of dogs using a new, less traumatizing suturing technique. A porous aliphatic polyurethane series with compr ession modulus of 150 kPa was implanted for comparison. Adhesion of th e implant to meniscal tissue was found to be essential for healing of the longitudinal lesion. Copolymer implants showed better adhesion, pr obably due to the higher degradation rate of the copolymer. Fibrocarti lage formation was found to be affected by the compression modulus of the implant. Implants with a modulus of 40 kPa did not show ingrowth o f fibrocartilage, whereas implants with compression moduli of 100 and 150 kPa yielded 50-70 and 80-100% fibrocartilage respectively. During degradation the copolymer phase separated into a crystalline phase con taining mainly L-lactide and an amorphous phase containing mainly epsi lon-caprolactone. The copolymer degraded through bulk degradation. (C) 1997 Elsevier Science Limited.