Effects of Hydrated Rate on Compressed Deformation of Natural Articular Cartilage

Abstract：Objective To study effects of hydrated rate on compressed deformation properties of natural articular cartilage. Methods The mass losses of pure cartilage, subchondral bone and cartilage sample were measured under different volatilization time with constant vacuum temperature container of 40 ℃ , and confined compressed deformation of different hydrated rates was measured using UMT-2 multi-specimen test system. Combined with cartilage structural equation originated by Mow, the aggregated modulus and permeability of cartilage tissue were obtained. Results The mass losses of pure cartilage, subchondral bone and cartilage sample functioned with a non-linear ascending relation with volatilization time in the environmental temperature of 40 ℃. The volatilization time for different hydrated rates of 75% , 50% , 25% and 0% was 17 min, 35 min, 54 min and 100 min, respectively. Higher hydrated rate produced more compressed deformation, lower aggregated modulus and higher permeability. Conclusion The viscoelastic mechanisms of flow-dependence and flow-inde pendence are manifested by compressed deformations while the aggregated modulus and permeability could quantitatively depict the mutual relation between hydrated rate and compressed deformation.