Mechanical characterisation of a scaffold under monotonic and cyclic loading conditions

Abstract

Loading from daily activities or from intensive exercise can lead to increased risk of fracture. Implants designed for load bearing purposes, such as repair of articular cartilage and underlying subchondral bone in knees must have the necessary mechanical competence under long term physiological loadings. In this study, the mechanical behaviour of a polymer-based osteochondral scaffold was examined under monotonic and cyclic loading conditions in a phosphate buffered saline solution at 37°C. Monotonic compression tests at selected strain rates were performed in both confined and unconfined conditions to investigate the influence of confinement. The effects of strain rate and sample composition on mechanical properties were also studied. Multi-step cyclic tests were carried out with increasing compressive loads. Changes in secant modulus and residual strain accumulation are monitored. The secant modulus and the number of cycles to failure of the scaffold are obtained and compared with those of human trabecular bone (Topolinski et al., 2011).