Hip and pelvic pain

A 16-year-old female cross-country runner with a history of anorexia nervosa presented to the orthopaedic clinic with a 2-month history of right posterior hip and pelvic pain. She was running approximately 30 to 35 miles per week when she developed pain. She had tried nonsteroidal anti-inflammatory drugs (NSAIDs), ice, cross-training, and rest for 2 months prior without any relief of her symptoms. On presentation, she did not endorse amenorrhea or recent weight loss. Radiographs of her hip and pelvis at an outside hospital were negative for fracture. On examination, she had mild tenderness to palpation over the right sacroiliac (SI) joint. She had a negative straight leg raise on the affected and contralateral sides. FABER (flexion, abduction, external rotation) test was negative as well. She had a reproduction of mild posterior sacral pain with hip flexion and adduction. Given her vague symptoms that persisted for months despite conservative therapy, magnetic resonance imaging (MRI) of the pelvis was performed.