[Total hip arthroplasty for Crowe type Ⅳ developmental dysplasia of the hip acetabular localization and...

Objective: To introduce an acetabular reconstruction technique for total hip arthroplasty (THA) in patients with Crowe type Ⅳ developmental dysplasia of the hip (DDH), and report its mid-term clinical outcomes. Methods: This is a retrospective case series study. Clinical data of 231 patients (310 hips) with Crowe type Ⅳ DDH who consecutively underwent THA via the posterolateral approach at the First and the Fourth Medical Centers of the Chinese People's Liberation Army General Hospital from August 2018 to April 2024 were retrospectively analyzed, and all patients had complete surgical and follow-up records. There were 17 males and 214 females, with an age of (43.9±9.8) years (range:18 to 60 years) and a body mass index of (24.0±3.1) kg/m² (range:17 to 30 kg/m²). Intraoperatively, the "ABCDE" method for true acetabulum identification (A: acetabular capsule; B: bone ridge; C: ligamentum capitis femoris; D: detect with index finger; E: exploration via ligamentum transversum) was adopted to precisely locate the true acetabulum, together with standardized operative essentials for acetabular reaming and acetabular cup implantation. All patients were followed up for no less than 1 year postoperatively. Preoperative and postoperative Harris Hip Score (HHS) and leg length discrepancy were measured and recorded, and perioperative complications were documented. The paired-sample t-test was used to compare preoperative and postoperative indicators. Results: All patients successfully received the surgery and completed follow-up. Among all hips, 223 were treated with robotic or navigation-assisted THA, and 87 with conventional THA. The operative time was (131.7±27.5) min (range:91 to 170 min). Intraoperatively, ceramic-on-ceramic bearing surfaces were used in 195 hips, ceramic-on-highly cross-linked polyethylene in 114 hips, and metal-on-polyethylene in 1 hip. Modular femoral stems were implanted in all hips, and subtrochanteric osteotomy was performed in 205 hips. The postoperative hospital stay was (5.2±2.8) d (range:3 to 9 d). The follow-up period was (28.8±14.2) months (range:12 to 46 months). Acetabulum-related complications occurred in 6 hips, including 3 cases of hip dislocation and 3 cases of acetabular fracture; secondary open reduction surgery was performed in 3 hips due to postoperative dislocation. The HHS significantly increased from preoperative (60.0±14.1) points (range:40 to 74 points) to postoperative (95.9±3.1) points (range:88 to 99 points) (t=32.450, P<0.01). The absolute value of postoperative leg length discrepancy was (6.5±3.3) mm (range:0 to 18 mm), which was significantly lower than the preoperative value of (17.6±11.2) mm (range:1 to 50 mm) (t=9.152, P<0.01). Conclusion: The true acetabulum localization and acetabular reconstruction technique adopted in this study can accurately identify the native acetabulum, improve the stability of the acetabular component, and significantly restore hip function, which provides certain clinical references for acetabular reconstruction in patients with Crowe type Ⅳ DDH.