This article presents critical issues related to the interpretation of biomechanical findings of the hip joint for patients having undergone hip arthroplasty. The use of a gait, or biomechanical, analysis provides objective evidence of the efficiency of the treatments or the effectiveness of hip replacement approaches. Based on our biomechanical analysis, patients who have undergone total hip arthroplasty use a stair ascent and descent strategy allowing them to significantly reduce loading at the prosthetic hip joint. Since hip joint reaction forces are highly dependent on muscle activation, the THA group have adopted a neuromuscular control strategy that is enabling them to reduce loading on the prosthetic hip joint. It could also be a joint loading pattern that stems from a muscular deficiency emerging either from several years of loading avoidance on the affected hip joint or from the surgical procedure. Therefore, a biomechanical analysis of human motion is a valuable tool for the orthopedic surgeon to objectively quantify joint motion and the forces producing this motion.