Clinically evident disturbance of the obturator nerve following total hip replacement is rare, although one prospective study demonstrated subclinical electromyographic abnormalities in thirteen of thirty extremities9. Anatomical studies, however, have revealed that there is a risk of serious injury of the obturator nerve if fixation screws in the anterior or central region of the acetabulum perforate the medial wall of the acetabulum4,8. We report the case of a patient in whom a symptomatic lesion of the obturator nerve developed after fixation of an acetabular reinforcement ring with screws during a total hip arthroplasty.
A sixty-three-year-old woman who had osteoarthrosis of the left hip joint was managed with total hip replacement with use of an acetabular reinforcement ring that was made of titanium. Postoperatively, mobilization of the patient was hampered by pain in the medial aspect of the thigh and weakness of the adductors of the hip; these symptoms had not been present preoperatively, and transient disturbance of the obturator nerve was suspected. One year after the operation, a neurological examination revealed atrophy and paresis of the adductor muscles (strength, grade 2 of 5), absence of the adductor reflex, and hypoesthesia in the medial aspect of the distal part of the left thigh. Electromyography demonstrated normal findings in the rectus femoris and iliopsoas muscles but partial denervation of the adductor magnus muscle; these results were consistent with a lesion of the obturator nerve. The patient was first seen in our clinic fourteen months after the operation, at which time the neurological symptoms were identical to those that had been noted at one year; the patient still used crutches for walking outdoors. Radiographs made at that time showed that two of the four screws that had been used for fixation of the acetabular reinforcement ring had …
Enter your JBJS login information below.
Please note that your username is the email address you provided when you registered.