[Objective] Posteroanterior weight-bearing radiographs,made with the knee in 45 degrees of flexion while the patient was standing on the homolateral foot,were compared with the weight-bearing anteroposterior radiographs with both knees in full extention,in order to find a more sensitive method to detect knee osteoarthritis.[Methods]Seventeen osteoarthritis knees were radiographed in the weight-bearing anteroposterior view with both knees in full extention and in the weight-bearing posteroanterior view with the knee in 45 degrees of flexion while standing on the homolateral foot.The minimum joint space width of all the radiograph were measured.The data were analysed statistically with SPSS 11.5.[Results]The mean minimum joint space width of the medial compart in extended knee view and standing on the homolateral foot were 4.65 mm?1.44 mm and 2.52 mm?1.69 mm,respectively(P