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 changes in the trabecular morphology around the bone cyst using our bone remodeling simulation method using three models, which are a normal model, high density model and low density model at the peripheral region of the bone cyst. As a result, we found differences of morphological change around the bone cyst between the high and low models. Bone resorption occurred in the high density model, while bone formation occurred in the low density model on the periphery of the bone cyst. These results correspond with the clinical report; a region of high bone density appears around bone cysts in osteoarthritis. The efficiency of our simulation method to understand the mechanism of bone cyst growth is discussed.
