Early Functional and Radiographic Outcomes of Stable Fixation with a Derotational Plate in Subtrochanteric Osteotomy for Crowe IV Developmental Dysplasia of the Hip.

Background: Developmental dysplasia of the hip (DDH) Crowe type IV poses significant surgical challenges during total hip arthroplasty (THA), often necessitating subtrochanteric shortening osteotomy (SSO) to achieve proper reduction and limb length restoration. Stable fixation of the osteotomy site is crucial for achieving reliable union and favorable functional outcomes. Objective: To evaluate early clinical and radiographic outcomes of stable fixation using a derotational plate in subtrochanteric osteotomy for Crowe IV DDH. Methods: A prospective cohort study was conducted on 28 patients (30 hips) with Crowe IV DDH who underwent THA combined with subtrochanteric osteotomy stabilized by a derotational plate. Clinical evaluation included the Harris Hip Score (HHS), Oxford Hip Score (OHS), and Visual Analogue Scale (VAS) for pain, assessed preoperatively and at 12 months postoperatively. Radiographic analysis focused on osteotomy union, implant stability, and restoration of limb length. Results: All patients achieved union at the osteotomy site within 6 months, with no cases of nonunion or implant failure. Mean HHS improved from 38.5 ± 6.2 preoperatively to 89.7 ± 4.3 postoperatively (p < 0.001). Mean OHS increased from 17.4 ± 3.1 to 41.2 ± 2.8 (p < 0.001). VAS scores significantly decreased from 7.8 ± 1.0 to 1.6 ± 0.7 (p < 0.001). Complications were minimal, with one intraoperative femoral fissure (3.3%). Conclusion: Stable fixation with a derotational plate in subtrochanteric osteotomy for Crowe IV DDH provides reliable union, excellent early functional recovery, and significant pain reduction at 12 months. These findings support its clinical effectiveness as a fixation method in complex THA cases.