MRI of lower extremity impingement and friction syndromes in children

Abstract

Although generally more common in adults, lower extremity impingement and friction syn-dromes are also observed in the pediatric age group. Encompassing femoroacetabular impinge-ment, iliopsoas impingement, subspine impingement, and ischiofemoral impingement around the hip; patellar tendon-lateral femoral condyle friction syndrome; iliotibial band friction syn-drome; and medial synovial plica syndrome in the knee as well as talocalcaneal impingement on the hindfoot, these syndromes frequently cause pain and may mimic other, and occasionally more ominous, conditions in children. Magnetic resonance imaging (MRI) plays a key role in the diagnosis of musculoskeletal impingement and friction syndromes. Iliopsoas, subspine, and is-chiofemoral impingements have been recently described, while some features of femoroacetab-ular and talocalcaneal impingements have recently gained increased relevance in the pediatric population. Fellowship-trained pediatric radiologists and radiologists with imaging workloads of exclusively or overwhelmingly pediatric patients (particularly those without a structured mus-culoskeletal imaging program as part of their imaging training) specifically need to be aware of these rare syndromes that mostly have quite characteristic imaging findings. This review high-lights MRI features of lower extremity impingement and friction syndromes in children and pro-vides updated pertinent pathophysiologic and clinical data.