Surgical treatment of limb-length discrepancy following total hip arthroplasty

BACKGROUND: Although most patients with limb-length discrepancy following total hip arthroplasty have manageable symptoms, others may be disabled as a result of pain or functional impairment. In these patients, reoperation may be indicated to equalize the limb lengths. There is a paucity of published data regarding the outcome of surgical intervention to treat this problem. The purpose of the present study was to evaluate the results of revision hip surgery for the treatment of symptomatic limb-length discrepancy. METHODS: We retrospectively reviewed the clinical and radiographic records of patients who had undergone revision hip surgery at our institution for the treatment of a symptomatic limb-length discrepancy following a previous total hip arthroplasty. We identified twenty-one patients (twenty-one hips) who had an average age of sixty-six years at the time of revision hip arthroplasty. The average duration of follow-up was 2.8 years, and no patient was lost to follow-up. The indications for revision hip arthroplasty were severe hip and/or back pain for eleven patients, instability of the hip for eight, hip pain and ipsilateral limb paresthesia for one, and hip pain and ipsilateral foot drop for one. RESULTS: Revision arthroplasty was performed at a mean of eight months (range, six days to six years) after primary total hip replacement. The mean limb-length discrepancy at the time of the revision was 4 cm (range, 2 to 7 cm). Following revision arthroplasty, which involved revision of a malpositioned acetabular and/or femoral component, equalization of the limb lengths was achieved in fifteen patients. In the remaining six patients, the mean discrepancy had decreased to 1 cm. The mean Harris hip score improved significantly, from 56.5 points before the revision to 83.2 points at the time of the latest follow-up (p < 0.005). All but two patients were satisfied with the outcome of the revision surgery. CONCLUSIONS: Limb-length discrepancy following hip arthroplasty can be associated with pain, paresthesia, and hip instability. In these patients, careful evaluation of the position and orientation of the components may reveal the cause of the discrepancy. Revision arthroplasty may be indicated when a surgically correctable cause of limb-length discrepancy can be identified.