Ulnar Nerve Dislocation and Subluxation from the Cubital Tunnel Are Common in College Athletes

Background: Hypermobility of the ulnar nerve from the cubital tunnel reportedly occurs in healthy people without symptoms of ulnar neuropathy. However, the occurrence rate in athletes is unknown. We examined the occurrence rate of ulnar nerve hypermobility using ultrasonography, symptoms, and physical findings in athletes and compared the results of four types of sports. Methods: Medical charts of college athletes competing in baseball, rugby, soccer, and long-distance running between March and November 2018 were retrospectively examined. Dynamic evaluation of the ulnar nerve was performed using ultrasonography and categorized as Types N, S, and D respectively, indicating normal position, subluxation, and dislocation. Subjective and objective findings were evaluated. Results: The present study included 246 male athletes (mean age, 19.7 years; 492 elbows) including 46% Type D, 29.8% Type S, and 24.2% Type N. Subjective findings showed pain and dysesthesia in 9% and 4.5% of participants, respectively, whereas objective findings showed Tinel sign in 6%, nerve tension test in 1.3%, Froment's sign in 0.5%, and weakness of strength of opponens digiti minimi muscle in 8% of patients with Types D and S. Conclusions: There was a high-frequency hypermobility of the ulnar nerve from the cubital tunnel with or without subjective and objective findings in college athletes.