Which way forward? Comparing radiological outcomes using three different surgical approaches in robotic assisted total hip arthroplasty.

Objectives: To assess the accuracy and precision of acetabular component placement in robot-assisted surgery total hip arthroplasty (RAS-THA) using three different approaches.

Methods: This study is a secondary analysis from a multicenter, randomized controlled trial comparing the Trex RS Hip 1.0 robot navigation system across different surgical approaches. It involved 145 patients treated at three Chinese medical centers from June 2021 to July 2022. Patients with end-stage joint disease were randomly assigned to either the RAS or control group. Acetabular component positioning was evaluated radiographically, and registration accuracy was measured using Root Mean Square Error (RMSE).

Results: The overall RMSE was 0.72 mm (SD = 0.24 mm), indicating consistent accuracy regardless of surgical approach. Significant variations in anteversion were noted across groups (p = 0.001). Lateral RAS-THA showed enhanced precision. The RAS Direct Anterior Approach (DAA) group had the least deviation in the rotation center's horizontal distance (0.89 ± 1.14 mm, p = 0.0014) and minimal leg length discrepancy (2.41 ± 1.17 mm). The RAS DAA approach also produced more consistent results.

Conclusion: Robotic assistance in THA, especially via the DAA approach, enhances the accuracy and precision of acetabular component positioning. Consistent registration accuracy across various surgical approaches confirms the reliability of these methods for THA.

Clinical trial registration: www.clinicaltrials.gov identifier is ChiCTR2100044124.