Background: The superior gluteal nerve can be damaged during the transgluteal approach to the hip in total hip arthroplasty.
Methods: We studied 30 patients with hip dysplasia who underwent total hip arthroplasty through the transgluteal approach. The course of the inferior branch of the superior gluteal nerve was identified using a nerve stimulator. The distance between the nerve and the tip of the greater trochanter was measured.
Results: The mean distance was 37 (25-45) mm at the anterior third, 40 (30-50) mm at the middle third, and 44 (35-55) mm at the posterior third of the gluteus medius. The distance was influenced by the severity of hip dysplasia and decreased as the degree of hip dysplasia became more severe.
Interpretation: A 3-cm safe zone is appropriate in most dysplastic hips. In severely dysplastic hips, however, the superior gluteal nerve occasionally coursed within 3 cm of the tip of the greater trochanter. In such hips, a nerve stimulator can be used to identify the nerve.