Muscle damage in minimally invasive total hip arthroplasty: MRI evidence that it is not significant.

The prevalence of damage to the musculature surrounding the hip joint was assessed in a random selection of patients who had a unilateral primary total hip replacement with either the two-incision minimally invasive technique, the standard posterolateral approach, or the direct lateral approach. The musculature of the operated hip was compared with that of the normal contralateral side using MRI with a special metal subtraction protocol that allowed visualization of the muscles and tendons while minimizing metal artifacts. All patients had undergone total hip arthroplasty at least 18 months before the investigation. The data show that the standard posterolateral and direct lateral approaches are associated with an increased incidence of postoperative alterations in the hip muscles after total hip arthroplasty, when compared with two-incision minimally invasive hip replacement. The results from this study suggest that the two-incision technique for total hip replacement may have muscle-sparing advantages over other standard approaches.