Abstract
Osteoarthritis of the hip occurs from an abnormality in the shape of a hip joint. During the progression of osteoarthritis, a fluid-filled cavity called "bone cyst" appears and enlarges in cancellous bone, which leads to fracture around the cyst in the bone tissue. Because osteoarthritis relates to the mechanical condition of the bone tissue, it is probably expected that the growth of a bone cyst progresses with bone remodeling. Elucidation of the growth process of a bone cyst is thus important for understanding the mechanism of osteoarthritis of the hip. In this study, we estimated relationship between changes in wall thickness of bone cyst and growth of bone cyst by using our bone remodeling simulation method. As a result, we found difference of ratio of voids around bone cyst which leads to increase bone cyst, depending on the thickness of the cyst wall between the remodeled models. The voids surrounding bone cyst in the model having thin cyst wall was large, while the voids in the model having thick cyst wall was small. These results suggest that bone cyst grows due to increase of voids by bone resorption and growth speed of the cyst changes depending on the thickness of the cyst wall.
