Caput valgum associated with developmental dysplasia of the hip: management by transphyseal screw fixation

PURPOSE: A late finding of some hips treated for developmental dysplasia of the hip (DDH) is a growth disturbance of the lateral proximal femoral physis, which results in caput valgum and possibly osteoarthritis. Current treatment options include complete epiphysiodesis of the proximal femoral physis or a corrective proximal femoral osteotomy. Alternatively, a transphyseal screw through the inferomedial proximal femoral physis that preserves superolateral growth might improve this deformity. METHODS: This study evaluates the effect of such a transphyseal screw on both femoral and acetabular development in patients with caput valgum following open treatment of DDH. These patients were followed clinically and radiographically until skeletal maturity. Preoperative and postoperative radiographs were assessed, measuring the proximal femoral physeal orientation (PFPO), the head–shaft angle (HSA), Sharp’s angle and the center edge angle of Wiberg (CE angle). RESULTS: Thirteen hips of 11 consecutive patients were followed prospectively. The age at the time of transphyseal screw placement was between 5 and 14 years. The mean improvement of the PFPO and HSA was 14° (p < 0.01) and 11° (p < 0.001), respectively. The mean improvement of Sharp’s angle and CE angle was 4.7° (p < 0.01) and 5.8° (p < 0.02), respectively. Five patients underwent screw revision. CONCLUSIONS: A transphyseal screw across the proximal femoral physis improved the proximal femur and acetabular geometry.