Acute Left Shoulder Pain After a Weight Lifting Injury

A 30-year-old man presented with a left shoulder injury from weight lifting 3 days prior. He was bench-pressing 125-lb dumbbells when his left hand drifted wide, and he felt his shoulder dislocate anteriorly. He was able to immediately reduce his left shoulder by pushing it posteriorly with his right hand. The patient’s shoulder then gradually lost mobility, and the pain worsened to 10 out of 10. He then needed to support his left arm. Radiography results were negative.

Physical examination showed significant ecchymosis overlying his left biceps (Figure 1). Pain limited the physical examination, particularly flexion and abduction of the left shoulder. The patient was not able to tolerate manual muscle testing of his left shoulder; however, strength was grossly 80% in all directions. The patient’s elbow flexion was unaffected and did not exacerbate shoulder pain.

QUESTION

Based on the patient’s history and physical examination, which one of the following is the most likely diagnosis?

• A. Acromioclavicular joint sprain (shoulder separation).

• B. Complete tear of the proximal biceps brachii.

• C. Pectoralis major tendon rupture.

• D. Shoulder instability.