The long-term impact of dividing Piriformis when performing a standard posterior approach to the hip has not been assessed. A less invasive approach in which the tendon is preserved has been described (the Piriformis-sparing minimally invasive [PSMI] approach). With advances in MRI technology it is now possible to image structures in close proximity to metal without artifact. The aim of the study was to compare the MRI features (muscle grade and bulk) of the divided and repaired Piriformis tendon group (by the standard posterior approach) with the preserved tendon group (by the PSMI approach). As part of an on-going randomized controlled trial comparing the PSMI approach with the standard posterior approach for total hip replacement, a subgroup of 20 consecutive patients who fulfilled the inclusion criteria were recruited. Patients received preoperative and 3 months and 2 year postoperative MRI scans. Patients and evaluators were blinded to allocation. Outcomes assessed included grade, volume and integrity of Piriformis.Background
Methods