Failure of capsular enhanced short external rotator repair after total hip replacement.

The failure rate of repaired short external rotator muscles was determined in 20 total hip replacements done in 19 patients. The piriformis, both obturator and gemellus muscles, and the capsule were released close to the femur in a single flap leaving the tendon-capsule junction intact. After implantation of the prosthetic components, the flap was transosseously reattached with three grasping stitches, each encompassing the entire tendon-capsule junction. Radiopaque markers were attached to each side of the suture. The distance between markers was measured intraoperatively and then determined on radiographs 1 day and 3 months postoperatively; 25 mm or more and at least double the distance measured intraoperatively indicated failure. In 15 of the 20 hips the repair failed; in three hips the repaired flap was pulled out within the first day, and in 12, within 3 months. Capsular enhanced repairs of the short extensor rotator muscles, using the technique described, largely are unable to withstand forces that occur at the site of repair during the healing process. The quality of other repair techniques should be determined to identify superior techniques.