Minimally Invasive Total Hip Arthroplasty Using a Transpiriformis Approach: A Preliminary Report

Background Continuing efforts have been made to develop minimally invasive surgery techniques for THA. One of the most commonly performed of these techniques is the mini-posterior approach. All reported series using this approach describe surgical detachment of the short external rotators of the hip. In 2008, Penenberg et al. described an innovative surgical technique that preserves the short external rotators. We present the results of a single-incision modification of this technique in 135 patients. Description of Technique This technique is based on preservation of all of the short external rotators of the hip with the exception of the piriformis or conjoined tendon. This single-incision technique required the development of specialized instrumentation for exposure and reaming of the acetabulum. The specialized retractors also successfully minimized trauma to the skin and subcutaneous tissue. Methods For the 135 patients undergoing THA with this technique, we analyzed demographic and operative data. We recorded complications, evaluated postoperative clinical function using the Harris hip score, and assessed cup abduction angle, cup anteversion, and stem alignment on radiographs. Minimum followup was 14 months (mean, 22 months; range, 14-33 months). Results There were no dislocations, no sciatic nerve palsies, no wound complications, and low transfusion rates (8%). The postoperative Harris hip score averaged 96.5 (range, 87-100). Overall acetabular cup abduction angle averaged 41A degrees (range, 21A degrees-49A degrees) and anteversion averaged 21A degrees (range, 15A degrees-27A degrees). Four percent and 2% of femoral components were inserted into more than 2A degrees varus and 2A degrees valgus alignment, respectively. Conclusions This technique shows promise as an alternative tissue-sparing method for minimally invasive THA.