Clinical outcomes of transposition osteotomy of the acetabulum for neurogenic hip dysplasia in skeletally mature patients.

BACKGROUND: This study aimed to clarify the clinical and radiographic outcomes of transposition osteotomy of the acetabulum (TOA) for neurogenic hip dysplasia in skeletally mature patients. METHODS: We retrospectively reviewed 12 patients (12 hips) with neurogenic hip dysplasia who underwent TOA between 1998 and 2019. There were three males and nine females, with a median age of 15 years. The median follow-up was 7.5 years (range, 2-21). Diagnoses included cerebral palsy, myelomeningocele, and other neurogenic conditions. Clinical outcomes were assessed using the Japanese Orthopaedic Association (JOA) hip score. Radiographic parameters, including migration percentage (MP), lateral center-edge angle (LCEA), Tönnis angle, Sharp angle, acetabular head index (AHI), anterior wall index (AWI), posterior wall index (PWI), and vertical distance (VD), were measured preoperatively, postoperatively, and at final follow-up. RESULTS: The median JOA score improved from 49 preoperatively to 69 at latest follow-up (p < 0.001), primarily due to improvement in the pain subscale (20 vs. 40, p = 0.001). No osteoarthritis progression occurred during follow-up. MP decreased from 75% preoperatively to 13% postoperatively (p < 0.001) and was maintained at 13% at the final follow-up, with radiographic containment (MP <33%) achieved in 92% of hips. Morphological parameters (LCEA, Tönnis angle, Sharp angle, AHI, and PWI) improved after TOA (all p < 0.001), except for AWI (p = 0.068), with 33-92% of hips falling within normal ranges. The median VD decreased from 21 mm preoperatively to 5.3 mm postoperatively (p = 0.005) but increased to 12 mm at the final follow-up (p = 0.015), with superior migration in three hips (25%). CONCLUSIONS: TOA restored acetabular coverage and provided durable radiographic containment in skeletally mature patients with neurogenic hip subluxation, with significant pain relief at mid-term follow-up. TOA represents a joint-preserving option for neurogenic hip dysplasia in skeletally mature patients.