Which nerves are at risk during the posterior approach to total hip arthroplasty and how can injuries be mitigated?

• A. Sciatic nerve and superior gluteal nerve; mitigate with careful dissection, preserving soft tissues, and proper positioning
• B. Femoral nerve and obturator nerve; mitigate with nerve blocks
• C. Saphenous nerve and pudendal nerve; mitigate by avoiding exposure
• D. Only the sciatic nerve is at risk; mitigate by avoiding dissection

Answer: (A)

In the posterior approach to total hip arthroplasty, the surgical pathway sits close to the sciatic nerve and the superior gluteal nerve as you split the gluteus maximus and work around the short external rotators. The sciatic nerve runs deep in the gluteal region and can be injured by traction or unintended dissection, especially if the exposure extends medially or if soft tissues are harshly retracted. The superior gluteal nerve courses above the gluteus medius/minimus and is at risk when the posterior interval is developed and the gluteal muscles are retracted. Protecting these nerves means using careful, tissue-sparing dissection, preserving the soft-tissue attachments to minimize traction, and positioning the leg to avoid excessive hip flexion, adduction, and internal rotation that can stretch the nerves. By identifying the correct anatomical plane, limiting aggressive retraction, and handling tissues gently, you reduce the chances of nerve injury. The other nerves mentioned are not primary concerns for this approach, and claiming only the sciatic nerve is at risk overlooks the real risk to the superior gluteal nerve in this route.