Cartilage-subchondral bone mechanical behaviour under impact loading

© 2015 Dr. Fatemeh MalekipourHigh impact loading to the knee joint can cause damage in articular cartilage and its underlying subchondral bone, leading to post-traumatic osteoarthritis (PTOA). Similar to primary osteoarthritis, PTOA is a disease that is associated with stiff and painful joints. In this thesis, mechanical testing of cartilage-bone plugs were combined with micro-computed tomography (µCT) image-based finite element simulation to understand the relative mechanical behaviour of cartilage and bone under impact compression, and also to quantify the intra-tissue stress state of the subchondral bone to identify the locations of tissue at high-risk of initial failure. Results suggest that the bone tissue with the highest risk of initial failure was located in the trabecular region below the cartilage. This finding is consistent with the sites of bone bruise in the magnetic resonance image (MRI) of patients with anterior cruciate ligament (ACL) injury. While treatment of the damaged tissue remains a challenge, understanding the mechanical behaviour of articular cartilage and subchondral bone under such impact loadings could help prevent the occurrence of such damages, and also determine the mechanism of damage initiation. The results can also help design tissue-engineering scaffolds that can replace the damaged cartilage-bone tissue