Outcomes at 1 Year After Total Hip Arthroplasty Combined With Low Femoral Neck Osteotomy vs Subtrochanteric Osteotomy in 73 Patients With Crowe Type IV Developmental Dysplasia of the Hip: A Retrospective Study.

BACKGROUND Crowe type IV developmental dysplasia of the hip (DDH) is characterized by complete proximal subluxation/dislocation of the femoral head, a small hypoplastic true acetabulum, and marked proximal femoral deformity. Total hip arthroplasty (THA) in Crowe IV DDH often requires femoral osteotomy for safe reduction. This retrospective study compared THA combined with low femoral neck osteotomy (LRNO) vs subtrochanteric osteotomy (SO). MATERIAL AND METHODS We reviewed 73 patients with Crowe IV DDH who underwent unilateral cementless THA from January 2017 to June 2024 (LRNO, n=37; SO, n=36). Primary outcomes were the Harris Hip Score (HHS) and Oxford Hip Score (OHS) at 12 months; scores were also assessed at 1, 3, and 6 months. Secondary outcomes included operative time, blood loss/transfusion, incision length, postoperative leg length discrepancy (LLD), perioperative laboratory changes, and complications. RESULTS Baseline characteristics were comparable (P>0.05). LRNO achieved higher HHS and OHS at 1 and 3 months (both P<0.001), with no between-group differences at 6 or 12 months (both P>0.05). LRNO had shorter operative time (P<0.001), smaller incision (P<0.001), less blood loss (P=0.002), lower transfusion requirements (blood, P<0.001; plasma, P=0.003), smaller postoperative LLD (P<0.001), and smaller decreases in hemoglobin and albumin (both P<0.001) than SO. Complication rates did not differ (P>0.05). CONCLUSIONS In Crowe IV DDH, THA with LRNO provides faster early functional recovery and improved perioperative efficiency with comparable 12-month function and short-term safety to SO.