Radiographic joint space width in patients with Crowe Type-I dysplastic hips.

UNLABELLED: Radiographic evaluation of preoperative joint space width is believed important to predict the long-term results of osteotomy. We asked whether joint space width differs in the supine and standing positions in patients with Crowe Type-1 osteoarthritis (OA) secondary to developmental dysplasia of the hip (DDH). Joint space width was measured in the supine and standing positions in 146 women and 16 men (231 hips) with OA. Subjects had a mean age of 46.7 years (range, 22-59 years). Differences were seen on radiographs in joint space width between supine (2.35 +/- 1.65 mm; range, 0.1-6.2 mm) and standing (2.04 +/- 1.78 mm; range, 0.0-5.9 mm). In 27 of 172 hips with greater than 1 mm joint space in the supine position, joint space width was decreased by greater than 1 mm in the standing position. To evaluate preoperative joint space width in patients scheduled for osteotomy, radiographs should be obtained with the patient in the standing position. LEVEL OF EVIDENCE: Level IV, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.