The changes of the leg alignment and the joint space were evaluated in 46 osteoarthrotic knees before and after barrel-vault osteotomy. Lateral opening angles (α-angle), tibial angles, passing points of Mikulicz's mechanical line (M-line) and femoro-tibial angles (FTA) in each standing and supine position were measured on pre- and post-operative X-ray. Postoperative mean values or degrees of tibial angle, M-line and FTA were 81.7°, lateral 38.2% and 165.6° respectively. Preoperative α-angles were 2.9° in supine position and 6.1° in standing position. The mean postoperative α-angle in standing position was 2.6°, which was similar to the preoperative one in supine position. These results suggest that the correct angle in barrel-vault osteotomy had better be determined on the preoperative A-P view X-ray in supine position.
