Comparison of Cubital Tunnel Syndrome with or without Anconeus Epitrochlearis: Are They Different?

ABSTRACT

PURPOSE: To assess the clinical difference between cubital tunnel syndrome with anconeus epitrochlearis (AE) and idiopathic cubital tunnel syndrome without known other causes. METHODS: This cross-sectional study included the 326 patients who were subjected to surgery because of cubital tunnel syndrome from 2008 to 2014. After exclusion of patients with other known causes of cubital tunnel syndrome, a total of 107 patients were divided into two groups; patients with and without AE. The clinical differences between two groups were analyzed retrospectively; age, sex, presence of intrinsic muscle atrophy, interval from symptom development to surgery, pinch power, the disabilities of the arm, shoulder and hand score and the nerve conduction velocity (NCV). RESULTS: Thirty four (10.4%) patients, being subjected to surgery had the AE. Among 107 patients who had no other known causes, 26 patients had AE. 19 out of 26 patients with AE was male. Average age of patients with AE was significantly younger. The interval from symptom development to surgery in AE patients was significantly shorter. Motor NCV of ulnar nerve at above elbow joint in comparison with that at below elbow joint in AE patient was more significantly decreased (14.3 m/sec vs. 8.3 m/sec). CONCLUSION: The AE in cubital tunnel syndrome is no more rare structure. In younger male patients with rapidly progressive worsening cubital tunnel symptoms, and if there is significant decrease of ulnar motor nerve velocity at above elbow in comparison with at below elbow, the AE should be considered as cause of ulnar neuropathy.