Secondary osteoarthritis of the hip jjoints is a common disease and is frequently followed by chronic sublexation and dislocation. Twenty four cases of the secondary osteoarthritis associated with chronic subluxation and dislocation of the hip joints were evaluated with plain radiography and computed tomotraphy. We retrospectively analyzed 1) the ossification and calcification of the acetabular labrum, 2) the thickeness of the quadrilateral plate of the ilium, and 3) anteroposterior diameter of the acetabulum. The changes of the hip joints in subluxation (n=14) revealed ossification of the acetabular labrum in 12 cases (86%), thickening of the quadriateral plate of the ilium in 11 cases (78%) but anteroposterior diameter of the acetabulum was not changed The changes of the hip joints in dislocation (n=10) revealed no evidence of the ossification of the acetabular labrum, thickening of the quadrilateral plate of the ilium in 10 cases (100%) and decreased anteroposterior diameter of the acetabulum. We conclude that CT findings of subluxation and dislocation of the hip joints can be helpful in the evaluation of the secondary osteoarthritis of the hip joints.