Ultrasound Finding of Ischiofemoral Impingement Syndrome and Novel Treatment With Botulinum Toxin Chemodenervation: A Case Report

Ischiofemoral impingement syndrome (IFIS) is a rare and poorly understood condition that leads to deep gluteal pain, groin, and/or medial thigh pain. It has unique diagnostic challenges, with limited nonoperative treatment options. It is caused by the impingement of the quadratus femoris by the lesser trochanter and the ischium. Currently, there are no validated physical examination maneuvers for IFIS, and the value of ischiofemoral interval for establishing IFIS is also uncertain. Ultrasound-guided corticosteroid injections have been reported. Here, we present a case of novel treatment of IFIS with botulinum chemodenervation that led to long-term symptomatic and functional improvement in this patient, with the unique ultrasound findings of the "eruption sign."