A Radiological Comparison of Robotic-Assisted Versus Manual Techniques in Total Hip Arthroplasty

Purpose

This study investigates the radiological outcomes of robotic-assisted total hip arthroplasty (RATHA) compared to manual total hip arthroplasty (mTHA), addressing the ongoing debate on the effectiveness of RATHA in achieving superior implant positioning accuracy.

Methods

A prospective cohort of 212 patients (103 robotic, 109 manual) underwent THA and were evaluated for postoperative radiological outcomes, focusing on the inclination and anteversion angles of the acetabular cup. Outlier prevalence was assessed based on angles outside the defined Lewinnek safe zones. All post-operative measurements were made using the BoneNinja application.

Results

High inter-observer and intra-observer reliabilities were observed, validating the measurement accuracy. The mean anteversion and inclination angles in the RATHA cohort were 40.5 ± 1.5 and 24.5 ± 3.1° respectively; and the mTHA cohort were 42.1 ± 4.9 and 24.9 ± 4.5°. There was a statistically significant difference in inclination angles between the two cohorts whereas the anteversion angles showed no difference. Majority of the conventional THRs (N = 72, 55.4%) were placed outside the safe zone for anteversion. The inclination angles revealed a highly significant difference between the cohorts (p < 0.0001), with all the robotic THRs (N = 121, 100%) being placed within the safe zone for inclination, whereas only 70% (N = 91) of the conventional THRs were within the safe zone. 97.5% of RA-THRs were within 3° of the proposed plan, demonstrating high accuracy.

Conclusion

RATHA significantly outperforms MTHA in radiological accuracy, achieving precise acetabular cup positioning with minimal outliers. These results advocate for RATHA's adoption in THA to enhance outcome predictability and affirm its reliability and safety over manual methods.