Leg-length inequalities following THA based on surgical technique

Leg-length inequality after total hip arthroplasty (THA) is a source of patient morbidity and concern, potentially contributing to nerve palsies, low back pain, and abnormal gait mechanics. The purpose of this study was to compare the degrees of leg-length inequality in patients undergoing primary THA via 3 surgical approaches: anterior, conventional posterior, and posterior-navigated (ie, using computer navigation). The authors reviewed the most recent 90 patients who underwent primary unilateral THA performed by a senior surgeon using an anterior, conventional posterior, or posterior-navigated approach. Measurements of leg-length inequality of the operative extremity were performed using interischial and interteardrop reference lines. One-way analysis of variance demonstrated no statistical difference in postoperative absolute leg-length inequality using interischial (P=.11) and interteardrop (P=.90) reference lines between the 3 approaches. In addition, no significant difference existed in the number of outliers in each cohort when measured relative to the interteardrop reference line. When a leg-length inequality more than 5 mm was considered an outlier, 31.1%, 20.0%, and 23.3% of patients in the anterior, conventional posterior, and posterior-navigated groups, respectively, were outliers (P values range, .12 to .71). Mean±SD absolute-leg-length inequality relative to the interteardrop reference line in the anterior, conventional posterior, and posterior-navigated groups were 3.8±3.9, 3.9±3.0, and 3.9±2.7 mm, respectively. The anterior and posterior-navigated approaches demonstrated no superiority over the conventional posterior approach; all methods provided reliable leg-length equalization.