Clinical outcomes of gradual reduction of late-detected developmental dysplasia of the hip using ultrasound-guided flexion abduction continuous traction: a midterm follow up study.

Reducing the avascular necrosis (AVN) rate in infants treated for developmental dysplasia of the hip (DDH) is important. We previously reported the clinical outcomes of gradual reduction via ultrasound-guided flexion abduction continuous traction (FACT-R), which achieved a 99% reduction with an AVN rate of 1.0% in infants <12 months. Here, we investigated the clinical outcomes of late-detected DDH after FACT-R. Infants ≥12 months who were treated with FACT-R for DDH from January 1995 to 2007 and followed up for 6 years were enrolled. Treatment comprised continuous traction, a hip-spica cast, and an abduction brace. The rates of reduction, redislocation, AVN, and secondary osteotomy surgery were evaluated. In the study patients (n = 26, hips 30), the mean age at the time of traction therapy was 23 months (range: 13-44) and the mean follow-up was 12.5 years (range: 6-16.4). Female gender and the left side were predominant. The rates of reduction, redislocation, and AVN were 100%, 0%, and 0%, respectively. However, 25 hips (83%) required secondary osteotomy surgery, including Salter innominate osteotomy in 21 hips, Salter innominate osteotomy combined with femoral osteotomy in 3 hips, and triple pelvic osteotomy in 1 hip. They had a larger acetabular index after FACT-R (P = 0.04) and a longer duration of FACT-R (P = 0.05). All hips were successfully reduced, with no redislocation or AVN. However, most hips required a secondary osteotomy surgery because of residual dysplasia. Careful follow-up and informed consent for secondary osteotomy surgery is thus essential.