Purpose
Ulnar nerve dislocation or subluxation from the cubital tunnel has been proposed as a risk factor of ulnar neuropathy. Previous studies reported that the frequency in the general population was up to 50%, while little is presently known in athletes despite their high demand.
This study aims to clarify 1) the frequency of ulnar nerve dislocation or subluxation and 2) frequency of subjective symptoms and objective findings of ulnar neuropathy in athletes.
Methods
The chart review of a medical check for the college athletes in our institute between March and November 2018 was retrospectively conducted. The subjects consisted of the four club activities of our college; Baseball, Rugby, Soccer, and Long-distance running. Inclusion criteria were a male athlete. Athletes with a history of elbow fracture were excluded. The location of ulnar never was assessed under ultrasound (US) examination by a board-certified orthopedic surgeon, an expert of ultrasound examinations for the musculocutaneous disorder. According to the criteria suggested in previous literature, three conditions were defined as the following; ulnar nerve dislocation (Type D, Figure 1), a subluxation (Type S, Figure 2), and normal (Type N, Figure 3).
The subjective symptoms and objective findings evaluated were as follows: Tinel sign, nerve tension test (NTT), Froment’s sign, and weakness of strength of opponens digiti minimi muscle. Another board-certified orthopaedic surgeon who was blinded for US assessment evaluated these. Statistical analysis was made on the difference in frequency between club activities.
Results
Two hundred and forty-six athletes (246 male, 0 female, mean age 19.7 years, 492 elbows) were included in the present study (Table 1). There were 226 elbows (46%) of type D, 147 elbows (29.8%) of type S, and 119 elbows (24.2%) of type N. Of those with type D and S, pain was in 9%, dysesthesia was 4.5%, Tinel sign was 6%, NTT was 1.3%, Froment’s sign was 0.5%, weakness of strength of opponens digiti minimi muscle was 8%. Type D and S were more frequent in Baseball and Rugby athletes than in Soccer and Long-distance running (p<0.001). In those, the US examination showed that the medial head of triceps pushed the ulnar nerve from the cubital tunnel (Figure 4-a, 4-b).
Conclusions
The outcomes from the present study showed that 75.8% of college athletes had ulnar nerve dislocation or subluxation from the cubital tunnel. Notably, the athlete who had a high demand for their upper limbs sustained those abnormalities more frequently. The findings could help early diagnosis of ulnar neuropathy in college athletes.