Accessory Anconeus Epitrochlearis In A Highschool Athlete: A Case Report

Case Diagnosis: A high school athlete is diagnosed with a accessory anconeus epitrochlearis muscle leading to ulnar neuropathy at the elbow with activity.

Case Description or Program Description: The patient presented to sports medicine clinic with right elbow pain. His exam and symptoms were consistent with ulnar nerve irritation at the elbow. He mainly noticed symptoms with rowing, throwing, and writing in school. Symptoms progressed to numbness and tingling of the 4th and 5th digit as well as hand weakness with activity. MRI of the elbow revealed an ulnar neuritis, an accessory anconeus epitrochlearis muscle and marrow signal changes of the medial epicondyle. After speaking with a surgeon regarding definite management, the patient returned for ultrasound guided steroid injection targeting perineural edema under the accessory anconeus epitrochlearis.

Setting: PM&R Sports Medicine Clinic

Assessment/Results: At the 4 week mark the patient noted significant improvement of his numbness and weakness of the hand. He was able to complete his high school rowing season, with surgery planned for definitive treatment which includes excision of the accessory anconeus epitrochlearis muscle as well as possible ulnar nerve transposition.

Discussion (relevance): Although the prevalence of an accessory anconeus epitrochlearis is varied in the literature, it is important to consider in patients with symptoms of an ulnar neuropathy at the elbow, especially in younger patients with activity related symptoms. Additionally, diagnostic ultrasound can aid in both the diagnosis and treatment of this condition.

Conclusions: A diagnosis of an accessory anconeus epitrochlearis should be considered in patients with activity related ulnar neuropathy at the elbow.