Does haptic robot-assisted total hip arthroplasty better restore native acetabular and femoral anatomy?

Background The objective was to evaluate whether total hip arthroplasty (THA) using haptic robot assistance restores hip geometry better than the free-hand technique. Methods Twelve robot-assisted and 14 free-hand unilateral THA patients underwent CT scan for three-dimensional (3D) hip models. The anteversion, inclination and hip joint centre locations of the native and implanted hips in each patient were quantified and compared. Results Significant increase of combined anteversion by 19.1 +/- 11.7 degrees and 23.5 +/- 23.6 degrees and decrease of cup inclination by 16.5 +/- 6.0 degrees and 10.2 +/- 6.8 degrees were observed in the robot-assisted and the free-hand THAs, respectively. Less variation in the difference of the component orientations (max 11.1 vs 18.3 degrees) and the femoral head centre (max 4.5 vs 6.3mm) were found in the robot-assisted group. Conclusion This study demonstrated that neither robot-assisted nor free-hand THAs had fully restored native hip geometry. However, the higher precision of the robot-assisted THA suggested that it has potential utility in restoring the native hip geometry. Copyright (C) 2015 John Wiley & Sons, Ltd.