The Relationship between Radiograph of Standing Position and Stage to Osteoarthritis of Hip

It is important to determine the coxarthrosis stage to evaluate joint space of the hip. The standing position reflects the influence of weight-bearing on the hip joint more clearly than the prone position. We experienced some cases of coxarthrosis whose stage in X-ray in the prone position changed in the standing position. We examined 77 hips of 50 patients with coxarthrosis, and classified then into the four stages according to only the narrowing of joint space in anterposterior X-ray of the hip : early-stage (41 hips), early phase of advanced-stage (11 hips), and late phase advanced-stage (25 hips). Terminal-stage was excluded. Thirteen hips (15.6%) moved to the progressive stage : 1 hips (2.4%) in early-stage, 3 hips (27.3%) in early phase advanced-stage, and 8 hips (32.0%) in late phase advanced-stage. In conclusion, as the coxarthrosis stage can change in the standing position, we need to pay attention to determining the coxarthrosis stage especially in advanced-stage cases.