Ipsilateral inflammatory neuropathy after hip surgery

Objective: To identify whether new ipsilateral weakness after hip surgery may be due to an inflammatory as opposed to a mechanical process. Patients and Methods: Seven patients (8 hip surgeries) seen between July 1, 2008, and June 30, 2011, developed unexplained ipsilateral leg weakness and pain within 1 month of hip surgery, mimicking mechanical etiologies. Cutaneous sensory nerve biopsy distant from the site of surgery was performed on all the patients. Patient medical records were reviewed for the clinical, electrophysiologic, radiologic, and pathologic features of the new neuropathy. Results: Results of all the nerve biopsies were abnormal, showing axonal damage (7 patients), inflammation (7 patients), signs of ischemic injury (7 patients), and nerve microvasculitis (6 patients). Six patients were treated with intravenous methylprednisolone. At median follow-up of 6 months, 6 patients showed improvement in function and pain. Conclusion: In this case series, we demonstrate that inflammatory neuropathy is an important etiologic consideration in some patients with ipsilateral weakness and pain after hip surgery. In these patients, the inflammatory mechanism was ischemic injury due to microvasculitis. Identification of these patients through clinical suspicion and subsequent nerve biopsy may lead to improved outcomes with prompt initiation of immunotherapy.