ABSTRACT
PURPOSE: Three surgical approaches in total hip arthroplasty (THA) were compared concerning: 1) clinical and radiological results; 2) innervation of the tensor fasciae latae and gluteal muscles; 3) clinical outcome of the nerve lesions; 4) sensitivity of the EMG analysis. METHODS: A total of 70 patients aged 39-79 years were evaluated clinically and electromyographically before and 3-9 months after THA in 2 centres using the anterolateral approach in 22, transgluteal approach in 33 and posterior approach in 15 patients, respectively. RESULTS: 1) Hip flexion, external rotation and Trendelenburg lurch were reduced and the centre of the rotation was higher after the anterolateral approach. 2) The inferior branch of the superior gluteal nerve of the tensor fasciae latae muscle was mostly damaged in the anterolateral approach (73% of lesions), whereas innervations of gluteus medius (9% of lesions) and maximus muscles (no lesion) were preserved. The transgluteal approach most often caused a partially denervated gluteus medius (81.8%) and the tensor fasciae latae (48%) and the gluteus maximus muscle only in 29%, respectively. After the posterior approach, partial denervation in the gluteus medius and maximus muscles were noted in 53.3% and 71.4%, respectively, whereas in the tensor fasciae latae muscle in only 14%. 3) The power of the abductors was not significantly reduced in partially denervated muscles. 4) The EMG examination is not sensitive enough to determine the relevant power of hip abductors. CONCLUSIONS: Despite some disadvantages associated with the anterolateral approach, the transgluteal and posterior approaches are often connected with a partial lesion of the gluteus medius and maximus muscles. In all approaches, clinical sequelae are not significant in primary THA.
