Mechanical behavior of articular cartilage soaked in physiological saline under cyclic compressive loading

Abstract

The ratcheting deformation of articular cartilage can be produced due to the repeated accumulations of compressive strain . The aim of this study was to investigate the ratcheting behavior of articular cartilage under cyclic compression. A series of cyclic compressive tests with different stress amplitudes and stress rates were conducted for pig knee articular cartilage, which was soaked in physiological saline. It is found that the ratcheting strain increases with rising of stress amplitude, while it decreases with rising of stress rate. The initial ratcheting strain of articular cartilage under cyclic compressive load increases rapidly, and then it exhibits a relatively stable status. The change of Young's modulus for cartilage is the same as evolution of ratcheting strain. Simultaneously, the optimized digital image correlation(DIC) technique was applied to study the ratcheting behavior of different layers for cartilage of online soaked under cyclic compression. It is found that the ratcheting behavior of cartilage is dependent on its depth. These results can provide the basis for disease treatment of clinical cartilage and cartilage defect repair.