EP1.71 Early Outcomes of Periacetabular Osteotomy Combined with Rotational Osteotomy at the Base of the Femoral Neck for Developmental Dysplasia of the Hip with Complex Femoral Sided Deformity and Inadequate Femoroacetabular Congruence

Abstract

Abstract Objective To evaluate early outcomes of combining periacetabular osteotomy (PAO) with femoral neck base rotational osteotomy for adolescent developmental dysplasia of the hip (DDH). This joint-preserving strategy targets multiplanar femoral deformities and inadequate femoroacetabular congruence in cases where isolated procedures fail. Methods We retrospectively analyzed 15 patients (15 hips; mean age 19, range 12–39 years) treated between 2015 and 2026. Inclusion criteria comprised acetabular dysplasia with severe femoral anteversion (>40°) and/or abnormal neck-shaft angle, incongruent reduction on 3D-CT (often following childhood conservative treatment), and Tönnis grade <2 with preserved cartilage on MRI. Using a surgical hip dislocation approach, patients underwent a femoral neck base osteotomy for 3D correction (anteversion, varus/valgus, and anterior/posterior rotation). A PAO followed to optimize acetabular coverage. We evaluated preoperative and postoperative Harris Hip Scores (HHS), Visual Analogue Scale (VAS) for pain, radiographic parameters (LCEA, anteversion, neck-shaft angle), and complication rates. Results Mean follow-up was 18 months (range, 6–36). At final follow-up, mean HHS improved significantly from 58.2 ± 6.4 to 91.5 ± 3.7, and VAS scores decreased from 4.8 ± 1.2 to 1.1 ± 0.8 (both P < 0.01). LCEA, femoral anteversion, and neck-shaft angles normalized, with postoperative 3D reconstructions confirming marked improvement in concentric joint congruence. No osteonecrosis, nonunion, or deep infections occurred. Three patients experienced transient lateral femoral cutaneous nerve palsy, which resolved spontaneously within three months. Conclusion Combining PAO with femoral neck base rotational osteotomy provides a precise, single-stage correction for adolescent DDH complicated by multiplanar proximal femoral deformities. This technique safely restores femoroacetabular congruence and yields excellent early clinical and radiographic outcomes. Long-term follow-up is necessary to confirm durability.