Posterior hip dislocation is a common complication after total hip replacement. Some authors recommend repair of the short external rotator tendons to stabilize the hip joint postoperatively. We evaluated the efficacy of repair of the piriformis tendon in 10 consecutive total hip replacement cases. Eight of the 10 repairs failed during the early postoperative period, and one of the two repairs that did not fail was in the only patient to sustain a posterior dislocation. We believe that repair of the piriformis tendon is of no significant benefit to the stability of a total hip replacement joint.