Young athletes, beware.

To cite: Cheng C-W, Liu AL-J. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2014204738 DESCRIPTION We present a case of a 15 year-old boy who experienced sudden left hip pain while sprinting. He had been training for the past 1 month and felt similar pain in his right hip 3 weeks earlier. Physical examination revealed severe tenderness near the left groin with limited flexion and abduction of the left hip. A radiograph showed a left anterior superior iliac spine (ASIS) avulsion fracture (figure 1) that was confirmed by CT, which also demonstrated a similar injury in the right hip (figures 2 and 3). Because the patient wanted to return to competition quickly, surgical fixation with screws was performed on the left hip while the minimally displaced injury in the right hip was treated conservatively. At 3-month follow-up, the patient had pain-free full range of hip movement and had returned to active sports without restriction. ASIS avulsion fractures are rare injuries that occur predominantly in male adolescents involved in sports. They are caused by abrupt, powerful and vigorous contractions at the attachments of the sartorius and tensor fascia lata muscles to the ASIS, as well as by sudden directional changes. Diagnosis can be performed based on medical history and physical examination, and confirmed by radiological investigation. Conservative treatment through rest, analgesics and rehabilitation usually yields good functional results. Surgical intervention is rarely indicated and is reserved for when the fracture fragment has migrated more than 2–3 cm, when meralgia paresthetica has occurred, when patients have failed conservative management or when they are eager for a quick recovery.