Robotic-assisted versus conventional total hip arthroplasty in Crowe Type 3-4 developmental dysplasia of the hip: a single-centre retrospective comparative cohort study.

AIM: The aim of this study was to compare the radiographic accuracy, clinical outcomes, and complications of robotic-assisted total hip arthroplasty (rTHA) and conventional total hip arthroplasty (cTHA) in patients with Crowe type 3-4 developmental dysplasia of the hip (DDH). METHODS: This single-centre retrospective comparative study included 38 patients with Crowe type 3-4 DDH who underwent total hip arthroplasty (THA) between 2016 and 2021 (20 rTHA, 18 cTHA). Clinical outcomes were evaluated using the Harris Hip Score (HHS). Acetabular cup inclination, anteversion, leg-length discrepancy (LLD), operative time, and complications were assessed at a mean follow-up of 32.0 ± 15.7 months in the rTHA group and 35.9 ± 19.0 months in the cTHA group. RESULTS: Acetabular anteversion and inclination were comparable between groups (p = 0.099 and p = 0.231). The proportion of cups within the Lewinnek safe zone was higher in the rTHA group (90% vs. 77%), without statistical significance (p = 0.302). No significant differences were observed in postoperative LLD or HHS. Operative time was significantly longer in the rTHA group (109.7 ± 33.6 vs. 93.5 ± 21.3 minutes, p = 0.042). Complication rates were similar between groups (2 vs. 2 cases). CONCLUSIONS: rTHA and cTHA demonstrated comparable radiographic and clinical outcomes in Crowe type 3-4 DDH at short- to mid-term follow-up. Although rTHA showed a trend toward improved implant positioning, operative time was longer. Larger prospective studies are required to determine potential long-term advantages of rTHA in severe DDH.