Comparison of anterior and posterior approaches for hip resurfacing arthroplasty: a gait analysis study.

BACKGROUND: Hip resurfacing arthroplasty (HRA) is now only rarely performed, but usually using the posterior approach (POS), while total hip arthroplasty is now commonly performed using the direct anterior approach (DAA). This study aims to compare outcomes between these two approaches for HRA using gait analysis, the oxford hip score (OHS), metabolic equivalent of task (MET). METHODS: Seventeen unilateral DAA and 17 POS HRA males were matched for age and BMI. Patients underwent instrumented treadmill gait analysis and completed patient reported outcome scores (PROMs) at a mean of 1.5 (0.9-1.8) years post-operatively. Kinematics and kinetics were recorded using motion capture and force plate data. Group differences were assessed using statistical parametric mapping. These data were compared to a group of 19 healthy male controls matched for age and BMI. RESULTS: Gait analysis postoperatively revealed no significant differences in hip kinematics in either the coronal or sagittal planes between the posterior and direct anterior approaches. Statistical parametric mapping showed no differences in vertical ground reaction forces across the stance phase. Spatiotemporal gait parameters, including top walking speed, cadence, step length, and step width, were comparable between groups and closely aligned with healthy controls. Both cohorts achieved similar postoperative OHS (mean:48, p = 0.651) and MET scores (POS:13.1 vs DAA:12.6, p = 0.856). CONCLUSIONS: This is the first study to compare gait following HRA via both the POS and DAA. At one-year postoperatively, both approaches restored gait patterns comparable to healthy controls, with no significant differences in kinematics, kinetics, or spatiotemporal parameters. PROMs were similarly excellent across groups indicating high functional recovery and engagement in moderate-to-vigorous physical activity.