Hip abductor strengths after total hip arthroplasty via the lateral and posterolateral approaches.

A retrospective control study was carried out to compare the postoperative hip abductor strengths after primary total hip arthroplasties via the lateral (lateral group; 38 hips) and posterolateral (posterior group; 40 hips) approaches. At a minimum of 2 years after total hip arthroplasty, abductor muscle strength was evaluated qualitatively by the Trendelenburg test and quantitatively using a dynamometer. The ratio of normalized strength of the reconstructed side to that of the nonoperated side was calculated (strength ratio). The Trendelenburg test was positive in 10 of 38 patients in the lateral group and in 11 of 40 patients in the posterior group. The average strength ratios of the lateral and posterior groups were 86.1% and 87.3%, respectively (P = .67). Strength ratio was positively correlated to femoral offset within both groups.

Ischemia of the lateral femoral cutaneous nerve during periacetabular osteotomy using Smith-Petersen approach.

BACKGROUND: Lateral femoral cutaneous nerve (LFCN) injury is a common complication in the Smith-Petersen approach to the hip. This complication may be induced by neural ischemia or direct trauma during the procedure. The purpose of this study was to investigate the relationship between the neural ischemia of LFCN and postoperative sensory disturbance. MATERIALS AND METHODS: Nineteen patients who underwent periacetabular osteotomy through the Smith-Petersen approach were investigated. To evaluate neural ischemia, we measured the blood flow of LFCN using a laser Doppler flowmetry. The measurements were performed before and after osteotomy at the point 1 cm distal from the lower border of the inguinal ligament. LFCN was retracted to the medial side during the procedure. There was no direct trauma to LFCN in all cases. Postoperative sensory disturbance was evaluated at 2 weeks, 3 months, and 1 year follow-up after surgery. RESULTS: After osteotomy, the blood flow of LFCN was decreased to 2.4 from 3.3 ml min(-1) 100 g(-1) when compared with that before osteotomy (P < 0.01). Postoperatively, 14 of 19 patients had sensory disturbance at 2 weeks, 8 of 19 patients at 3 months, and 2 of 19 patients at 1 year follow-up. The blood flows of both patients who had persistent symptoms over 1 year after surgery had been decreased by more than 50% during operation. CONCLUSIONS: Decrease of blood flow of LFCN by more than 50% seems to cause persistent symptoms after surgery through the Smith-Petersen approach even if direct trauma to the nerve is avoided. Excessive traction by retractors is thought to be the main cause of blood flow reduction.