Mechanical behaviour of Subchondral Bone: Elastic Moduli and Energy Dissipation in Subchondral Bone under Impact and Repetitive Loads

Abstract

The damage to osteochondral tissue can develop degenerative joint diseases such as subchondral bone necrosis, osteochondral fracture, and osteoarthritis. In the development of these joint diseases, the subchondral bone plays a crucial role due to several risk factors: obesity, hereditary, aging, gender, and intense mechanical loads. The intense mechanical loads include both trauma/impact and repetitive loads which occur during high-intensity training and have been identified as the primary risk factor in the development of joint diseases. In this dissertation, we utilized mechanical tests combined with digital image correlation and micro-computed tomography to study the mechanical behaviour (in particular, Elastic Modulus and Energy Dissipation) of subchondral bone under both trauma/impact and repetitive loads.

Results suggest that the presence of severe cartilage lesion in osteochondral tissue reduces the stiffness of cartilage and increases the compressive strain in the subchondral bone under trauma/impact loads. Moreover, the application of simulated physiological repetitive loads on subchondral bone has demonstrated the importance of the highest speeds in the development of the joint disease, consistent with the observations made in equine athletes. The results also exhibit the influence of microstructural properties on the mechanical behaviour of subchondral bone under repetitive loads. The results and approach of simulating physiological loading may be useful in optimizing training protocol and prevent joint diseases.