To compare gait patterns in patients with total hip arthroplasty (THA) and surface hip arthroplasty.Observational study.Outpatient biomechanical laboratory.Two groups of 10 surface hip arthroplasty and THA patients and 10 control subjects participated in the study (N=30). The patients were volunteers recruited from a larger randomized study.Not applicable.Gait patterns, hip abductor muscle strength, clinical outcomes, and radiographic analyses were compared between groups.In the sagittal plane, the THA group showed a larger flexor moment and larger mechanical work in H2S and K3S power bursts compared with surface hip arthroplasty and control subjects. In the frontal plane, both THA and surface hip arthroplasty patients had smaller hip abductor muscles energy generation (H3F) than the control group. No difference was found for the hip abductor muscles strength.In the THA group, the larger energy absorption in H2S and K3S would be a cost-effective mechanical adaptation to increase stability. The surface hip arthroplasty characteristics could allow the return to a more normative gait pattern compared with THA. The modification in the frontal plane in surface hip arthroplasty and THA would be related to the hip abductor muscles strength.