Abstract
In the progression of an osteoarthritis which arises from abnormality in the shape of a joint and its wear and tear, a fluid-filled hole "bone cyst" appears and enlarges and often leads to fracture. Because the osteoarthritis closely relates to the mechanical condition around the hip, the cyst growth is also expected to be connected to mechanical stimulus in the trabecular bone remodeling around the cyst. Mechanical elucidation of the process in the cyst growth is desired to understand the mechanism of osteoarthritis for its treatment. In this study, first, we performed stress analysis around the cyst in the coxal bone using a CT image-based model of the osteoarthritis in macro-scale. Second, the change in trabecular morphology around the cyst is estimated using our bone remodeling simulation method in micro-scale. As results, we found differences of stress distributions between the osteoarthritis model and the normal model. We also demonstrated that the total volume in the cyst model became greater although bone resorption occurred around the cyst, suggesting correspondence to the clinical finding that bone spicule is formed and bone volume around the cyst increases. The efficiency of our simulation methods to understand the mechanism of the cyst growth is discussed.
