Comparison of robotic and conventional total hip arthroplasty in Crowe type 3–4 hip dysplasia: a retrospective analysis of radiological precision and early clinical outcomes

Background: Total hip arthroplasty (THA) is an effective treatment for advanced hip osteoarthritis, particularly in complex cases such as Crowe Type 3 and 4 developmental dysplasia of the hip (DDH). This study aimed to compare radiological and early clinical outcomes of conventional (cTHA) and robotic (rTHA) THA in patients with Crowe Type 3 and 4 DDH. Methods: Patients who underwent cTHA or rTHA were retrospectively analysed. Preoperative and postoperative clinical parameters, including range of motion (ROM), visual analogue scale (VAS) pain scores, modified Harris Hip Score (mHHS), and leg-length discrepancy, were evaluated. Radiological assessments included implant positioning (acetabular inclination and anteversion, femoral anteversion) using x-ray and CT imaging. Operative durations for cTHA and rTHA were also compared. Results: A total of 45 patients (52 hips) were included. Both groups showed significant improvements in clinical and radiological outcomes. Postoperative VAS pain scores were lower in the rTHA group (1.35 ± 1.00 vs. 2.41 ± 1.14 for cTHA), and mHHS was higher (92.34 ± 5.68 vs. 79.68 ± 5.92 for cTHA). ROM and radiological parameters, such as acetabular inclination (37.11 ± 3.37° for rTHA vs. 41.13 ± 6.49° for cTHA) and anteversion (17.59 ± 1.78° for rTHA vs. 21.87 ± 1.71° for cTHA), were more precise in rTHA. Operative time was longer for rTHA (117.06 ± 8.16 vs. 79.71 ± 6.79 minutes). Conclusions: Robotic THA achieved better implant positioning and superior early clinical outcomes compared to conventional THA in complex DDH cases, despite longer surgical times.