Porous, resorbable, fiber-reinforced scaffolds tailored for articular cartilage repair

Porous 75:25 poly(D,L-lactide-co-glycolide) scaffolds reinforced with polyglycolide fibers were prepared with mechanical properties tailored for use in articular cartilage repair. Compression testing was performed to investigate the influence of physiological testing conditions, manufacturing method, anisotropic properties due to predominant fiber orientation, amounts of fiber reinforcement (0 to 20 wt, %), and viscoelasticity via a range of strain rates. Using the same testing modality, the mechanical properties of the scaffolds were compared with pig and goat articular cartilage. Results showed that mechanical properties of the scaffolds under physiological conditions (aqueous, 37 degrees C) were much lower than when tested under ambient conditions. The manufacturing method and anisotropy of the scaffolds significantly influenced the mechanical properties. The compressive modulus and yield strength proportionally increased with increasing fiber reinforcement up to 20%. From 0.01 to 10 mm/mm/min strain rate, the compressive modulus increased in a logarithmic fashion, and the yield strength increased in a semi-log fashion. The compressive modulus of the non-reinforced scaffolds was most similar to the pig and goat articular cartilage when compared using similar testing conditions and modality, but the improvement in yield strength using the stiffer scaffolds with fiber reinforcement could provide needed structural support for in vivo loads.