Upper Limb Nerve Injury - Baseball

Abstract

HISTORY: A 21 year old right-handed baseball player suffered a fracture of his left 4th metacarpal after being struck by a fastball. He underwent surgical correction of his injury and did not play baseball for the next four weeks. He then returned to play for two weeks without incident. At this time the patient took a two week vacation and upon return to training he experienced numbness in the ulnar distribution of his right hand, an "electric sensation" into his hand from his elbow when throwing, and grip incoordination. The only change to his training regimen was the addition of triceps push-ups for the first time, but he indicated that he was asymptomatic while doing them. PHYSICAL EXAMINATION: Weakness of the right ulnar hand intrinsic muscles and flexor digitorum profundus at the ring and small fingers was noted. Wrist flexion was minimally affected and strength was normal in all other areas. Decreased appreciation to light touch in the ulnar distribution of the right hand was also observed. No significant deformity was noted about the elbow and no snapping or popping was evident on routine examination. This phenomenon was appreciated, however, while the patient performed triceps push-ups. DIFFERENTIAL DIAGNOSIS Ulnar nerve entrapment at the elbow Ulnar neuropathy at the wrist C8-T1 radiculopathy Lower trunk/medial cord brachial plexopathy Neurogenic thoracic outlet syndrome TEST AND RESULTS: Electrodiagnosis: Electrodiagnostic studies demonstrated a moderate ulnar neuropathy with neurapraxic block just proximal to the medial epicondyle. Musculoskeletal ultrasound: High frequency ultrasound demonstrated proximal swelling of the right ulnar nerve just proximal to the medial epicondyle. Dramatic subluxation of the medial triceps tendon and ulnar nerve was observed over the medial epicondyle while the patient performed triceps push-ups. This was not seen during routine flexion/extension of the elbow. FINAL WORKING DIAGNOSIS: Dynamic subluxation of the triceps under load causing Snapping Triceps Syndrome with resultant Ulnar Neuropathy at the elbow. TREATMENT AND OUTCOMES: Recognition of this syndrome with avoidance of triceps push-ups and similar repetitive motions at the elbow led to a nearly complete resolution of symptoms and successful return to competitive baseball within four weeks.