[Peripheral nerve lesions after total hip endoprosthesis].

AIM OF THE STUDY: Lesions of peripheral nerves are serious complications associated with total hip replacements. Prognostic factors and treatment concepts have not been sufficiently defined. Improvements can occur spontaneously. This study aimed to evaluate risk factors and diagnostic aids, such as the velocity of nerve conduction (VNC) and electromyography (EMG). Furthermore, the effect of prognostic factors as well as conservative and invasive therapeutic measures on the regression of clinical symptoms was examined.

METHOD: From 1990 to 1996 1833 patients underwent total hip replacement. 1447 procedures were primary total hip replacements and 386 were revisions. 14 femoral nerve lesions (0.8%), 7 sciatic nerve lesions (0.4%) and 8 peroneal nerve lesions (0.4%) occurred. 19 patients were examined clinically, electromyographically and by means of VNC, 10 patients only clinically. In 5 patients a neurolysis was performed within the first postoperative year. All 29 patients underwent a recall examination in 1997 to evaluate the development of the clinical symptoms and if possible, VNC and EMG were performed.

RESULTS: Of the 7 patients with sciatic nerve lesions, two were free from symptoms at the time of recall, two still complained about residual symptoms and two showed no improvement of the lesion. One patient did not appear for follow-up. Of the 8 patients with peroneal nerve lesions, five were free from symptoms at the time of their recent examination, two showed residual symptoms and one patient did not appear. Of the 14 patients with femoral nerve lesions, four had recovered completely, eight showed residual symptoms, one patient did not improve and one patient had died.

CONCLUSIONS: Prognostic statements regarding the improvement after nerve lesions are possible only to a limited degree. However, it was found that the motor function tended to recover earlier than sensibility. We could not determine with clinical evaluations why some patients showed an improvement of their lesion while others did not. As well no clear correlation between the EMG and VNC results and the recession of the symptoms could be established.