Robotic-Assisted Total Hip Arthroplasty: Outcomes at Minimum Two-Year Follow-Up.

BACKGROUND: Component malposition in total hip arthroplasty (THA) contributes to instability and early failure. Robotic-assisted total hip arthroplasty (rTHA) utilizes CT-based planning with haptically-guided bone preparation and implant insertion to optimize component position accuracy. This study compared acetabular component position and postoperative complications following manual THA (mTHA) with rTHA.

MATERIALS AND METHODS: Consecutive primary THAs performed by one surgeon at three intervals were analyzed in this retrospective cohort study: the initial 100 consecutive manual THAs (mTHA) in clinical practice (year 2000), the last consecutive 100 mTHA before rTHA introduction (year 2011), and the first consecutive 100 rTHA (year 2012). Acetabular abduction (AAB) and anteversion (AAV) angles were measured using validated software. The Lewinnek safe zone was used to define accuracy (AAB 40°±10° and AAV 15°±10°). Comparisons included operative time, estimated blood loss (EBL), infection rate, and dislocation rate.

RESULTS: The rate of acetabular component placement within Lewinnek safe zone was the highest in the rTHA cohort (77%), followed by late mTHA (45%) and early mTHA (30%) (p<0.001). Robotic-assisted THA resulted in an additional 71% improvement in accuracy in the first year of use (p<0.001). Dislocation rate was 5% with early mTHA, 3% in the late mTHA cohort, and 0% in the rTHA cohort within the first two years postoperatively. There were no statistically significant differences in the rate of infection between groups.

CONCLUSION: Robotic-assisted THA improved acetabular component accuracy and reduced dislocation rates when compared with mTHA. Further study is needed to determine if similar improvements will be noted in larger multicenter studies using alternative surgical approaches.