Disclosures: Krupali Chokshi, MD: No financial relationships or conflicts of interest

Case Diagnosis: Sciatic Neuropathy from Acetabular Screw Impingement after Total Hip Arthroplasty

Case Description or Program Description: A 54-year old male presented to the emergency room after a bike accident and was found to have a comminuted impacted fracture of the left femoral neck/subcapital femur. The patient underwent a total hip arthoplasty (THA) via anterior approach. Post-operatively, he was noted to have 0/5 strength in dorsiflexion, plantarflexion, and no sensation to light touch on the lateral aspect of his foot. A CT scan revealed acetabular screws impinging on the sciatic nerve. He was diagnosed with left sciatic nerve neuropathy and returned to the OR for acetabular screw revision. Post-operatively sensation improved in his lateral foot with no improvement in motor function. He was transferred to acute rehabilitation. He progressed well in therapy and was prescribed a custom AFO, lined for sensory impairment. Upon discharge, he was ambulating 300 feet with axillary crutches. Three weeks post-operatively, an EMG confirmed severe sciatic neuropathy.

Setting: Acute inpatient rehabilitation facility

Assessment/Results: The patient had EMG confirmed sciatic neuropathy from an acetabular screw impinging on the nerve

Discussion (relevance): Sciatic nerve damage occurs in 1.5% of patients after primary THA. Mechanisms of injury include blunt trauma to the nerve, hematoma, vascular compromise, excessive limb lengthening, or compression by surgical material (such as screws or extrusion of cement). Positioning an acetabular screw in the posterior-inferior quadrant of the acetabulum can impinge on the sciatic nerve. This is repaired with a revision THA in which the screws are removed or replaced with a smaller size.

Conclusions: Sciatic nerve injury after a THA is a rare but disabling condition that can severely affect function and prolong post-operative rehabilitation course. Recognition of sensory-motor deficits, as well as possible mechanical etiologies of injury, can ensure prompt surgical revision. Prognosis can vary based on severity of nerve injury, with some studies showing full recovery in only 50% of cases. Rehabilitation includes pain management, physical therapy, electrical muscle stimulation and ankle foot ortheses to address foot drop.

Level of Evidence: Level IV

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/rare-case-of-sciatic-neuropathy-from-acetabular-screw-impingement-after-total-hip-arthroplasty/