Unusual cause of elbow pain in a baseball pitcher.

An adolescent, right hand-dominant, baseball pitcher presented to sports medicine clinic with posterolateral right elbow pain over 4 months. He rated his pain as 8/10 with pitching, especially at the late cocking phase of throwing. Prior to consult, he had rested 3 months from pitching, progressing to strengthening exercises, with no pain relief. On physical examination, he had 120° of active external rotation, 80° of active internal rotation, mild tenderness to palpation over the capitellum and normal elbow radiography. Magnetic resonance arthrogram of the right elbow revealed subtle, posterolateral joint capsular tear and adjacent synovial hypertrophy. The patient was diagnosed with elbow synovial fold syndrome that was causing impingement at the radiocapitellar joint and was referred to an orthopaedic surgeon. Arthroscopy revealed redundant tissue; scar formation at the radiocapitellar joint was debrided. The patient participated in physical therapy for 2 months and was able to start throwing 3 months later. © BMJ Publishing Group Limited 2018. No commercial re-use. See rights and permissions. Published by BMJ.