EP1.30 Ganz Periacetabular Osteotomy: Mid-term Outcomes for Acetabular Retroversion in Dysplasia

Abstract

Abstract Background Acetabular retroversion represents a distinct subtype of hip dysplasia characterized by decreased acetabular anteversion and relative posterior undercoverage. When surgical treatment is indicated, the Ganz periacetabular osteotomy (PAO) is commonly performed to restore acetabular orientation and improve hip biomechanics. However, technical considerations differ from PAO performed for classic lateral undercoverage, and evidence regarding mid- and long-term outcomes in this specific subgroup remains limited. Purpose To evaluate the mid-term clinical and radiographic outcomes of patients with acetabular retroversion dysplasia treated with periacetabular osteotomy. Methods A retrospective cohort study was conducted including 236 patients with hip dysplasia treated surgically. Among these, 19% presented acetabular retroversion and were included in the analysis. Mean age at surgery was 26 years (range 16–50), with a mean follow-up of 5 years. Clinical outcomes included pain measured by the Visual Analog Scale (VAS) and functional outcomes using the modified Harris Hip Score (mHHS). Radiographic evaluation included acetabular coverage percentage, lateral center-edge angle (Wiberg), and signs of acetabular retroversion on anteroposterior pelvic radiographs, including the crossover sign, ischial spine sign, and posterior wall sign. Progression of osteoarthritis was assessed using the Tönnis classification. Complications and survivorship of the native hip were also recorded. Results A significant improvement in functional outcomes was observed, with mHHS increasing from a mean preoperative score of 55 to 88 postoperatively (p < 0.001). Pain levels decreased significantly, with VAS improving from 7 preoperatively to 1 at final follow-up (p < 0.001). Clinically, 90% of patients reported satisfaction and returned to moderate or high levels of sports activity. Radiographically, correction of acetabular retroversion was achieved in all patients, with resolution of the crossover and posterior wall signs. Progression of osteoarthritis was minimal, with only 10% of patients progressing by one Tönnis grade. During follow-up, 0 patients required conversion to total hip arthroplasty. Conclusion Periacetabular osteotomy for acetabular retroversion dysplasia demonstrates favorable mid-term clinical and radiographic outcomes, with high rates of joint preservation and low complication rates. This procedure effectively restores acetabular orientation and may delay the progression of osteoarthritis in appropriately selected patients.