Incidence of piriformis tendon preservation on the dislocation rate of total hip replacement following the posterior approach: a series of 226 cases.

Background: Dislocation is a feared complication following total hip replacement (THR). While repairing the piriformis tendon after THR reduces dislocation, we analyze in this study the effect of piriformis tendon preservation on reducing the dislocation rate.

Material And Methods: 226 THRs were done following the usual posterior approach and by the same surgeon. All patients received the same prosthetic design. All cases were primary THR. After reaching the external rotators, the piriformis muscle was identified and dissected on its inferior border from the gemellus superior and elevated by a retractor. Further stages were performed in the usual manner. Patients were followed up for a mean of 3 years.

Results: 226 THRs were done for 217 patients, 118 of whom were females and 99 were males with a mean age of 62. Nine patients received bilateral THRs. 112 procedures were performed on the right side and 114 on the left side. THR was performed in 70 cases following femoral neck fractures and in 156 cases due to osteoarthritis. No intraoperative or long-term complications were found while preserving the piriformis. Postoperative hip X-rays showed good positioning of both the femoral and acetabular components. No cases of dislocation were identified after a mean follow-up of 3 years.

Conclusion: Preservation of the piriformis tendon during the postero-lateral approach in THR is a possible surgical technique that is easy to use and reproducible in both arthritic and traumatic conditions. It follows an anatomical intermuscular plan and permits full exposure of both the proximal femur and the acetabulum. Compared to the literature, preserving the piriformis tendon seems to be superior to repairing it in terms of dislocation of THR.