Sports Medicine Imaging Update

A healthy 18-year-old right-hand-dominant high school football player presented 6 weeks following an injury to his right shoulder. While playing right defensive end, the patient made an inside move on the opposing lineman, and another player collided with the medial aspect of his arm. The collision caused abrupt deceleration of both players and forced the injured player’s humerus to externally rotate. The arm did not dislocate, and the patient did not describe any instability, but he did experience acute right anterior shoulder pain and transient numbness. He finished the game and continued to play football in the intervening weeks. Initially he experienced night pain, but his main symptom was loss of strength (weakness of internal rotation) and dysesthesias in his right deltoid. He kept his arm more adducted during subsequent games to avoid pain and found it necessary to elevate his arm in order to extend the humerus to tackle. Despite aggressive training, he was unable to regain strength. Physical examination at presentation revealed a neurovascularly intact right upper extremity and good motion of the neck without pain. He showed no muscle atrophy but struggled to lift his right arm. He had a positive lift-off test and a positive O’Brien sign on the affected shoulder. Strength testing of the rotator cuff showed internal rotation weakness. His triceps muscle was strong, and his reflexes were rated as 2+ biceps and brachioradialis bilaterally, 1+ triceps on the left, and absent on the right. Electrodiagnostic testing showed no evidence of a brachial plexopathy. Radiographs showed a small ossific density anterior and medial to the humeral head that was seen on the West Point (Figure 1) and Stryker Notch views, possibly indicating a lesser tuberosity avulsion fracture, but only noted following magnetic resonance imaging (MRI). Magnetic resonance imaging demonstrated an avulsion of the subscapularis tendon with a fragment of bone that was displaced posteromedially (Figures 1-​-3).3). The tear comprised more than 50% of the subscapularis footprint without dislocation of the long head of the biceps tendon from the intertubercular groove. The superior-most fibers of the subscapularis were intact. There was injury to the anterior capsule without humeral or scapular avulsion of the anterior band of the inferior glenohumeral ligament. There was no Bankart lesion. Figure 1. West Point radiographic projection of the right shoulder demonstrate a small ossific density (arrow) anterior to the humeral head. Figure 3. Oblique sagittal intermediate echo-time fast-spin-echo MRI of the right shoulder demonstrates the avulsion fragment (arrow) surrounded by high-signal intensity fluid. Note the superior and anterior subscapularis tendon fibers, which were not disrupted, ... Figure 2. Axial intermediate echo-time fast-spin-echo MRI of the right shoulder demonstrates the avulsion fragment (arrow) displaced medially into the defect created by the subscapularis tendon tear. The superficial fibers of the subscapularis tendon are hyperintense ... At arthroscopy, a small split in the tissue overlying the subscapularis was identified; within this split, the tendon of the subscapularis was medially retracted. A small bone fragment was found at the edge of the retracted tendon. Debridement of the footprint of the subscapularis tendon was performed, and an anchor was placed. Debridement of the small bone fragment was also carried out, and the subscapularis was reattached directly using 2 sutures.