Most resurfacing arthroplasty is performed using the posterior approach, while total hip arthroplasty is increasingly performed via the anterior approach with objective benefit noted in the sagittal plane kinematics. We surmised that the muscle releases needed for resurfacing arthroplasty using the posterior approach would reduce the strength of push-off as seen in gait studies of total hip arthroplasty. Method 19 healthy controls were compared with 17 posterior and 17 anterior patients for hip resurfacing, recruited from a prospective gait study of lower limb arthroplasty. PROMs and gait characteristics were captured more than 12months following surgery. Oxford Hip Score, MET score and gait were analysed using ground reaction forces and motion capture. Statistical parametric mapping was used across the entire gait cycle. Results The median and modal OHS was 48/48 for both groups. The mean MET was 13.1 for posterior and 12.6 for anterior. Top walking speed of 7.5km/hr for the control and posterior were similar to the 7km/hr of anterior. Ground reaction forces were symmetric at all speeds. Maximum sagittal plane motion of 42° for posterior and 45° for anterior were indistinguishable from the control group throughout the range of motion. Coronal plane range was 15° for both groups – identical to the healthy controls. Discussion The gait characteristics of these two groups were indistinguishable even at higher speeds from the healthy control group. The speed reached and the different gait characteristics did not differ, despite the substantial difference in soft tissue releases needed. There may be a benefit to using the anterior approach for resurfacing arthroplasty, but ground reaction forces and motion capture in a gait lab at 12 months was unable to detect any lasting impact of either approach. Surgeons should continue to use their preferred approach.
Brkljac et al. (Thu,) studied this question.