Anterior Subcutaneous Transposition of the Ulnar Nerve Affects Elbow Range of Motion: A Mean 13.5 Years of Follow-up

BACKGROUND Surgical decompression of the ulnar nerve is effective for cubital tunnel syndrome. However, deep approaches may result in iatrogenic elbow stiffness. This long-term study was to evaluate the range of motion (ROM) of the elbow and functional outcomes after anterior subcutaneous transposition. METHODS A total of 115 patients (78 male and 37 female; mean age: 46.6 years) who underwent anterior subcutaneous transposition of the ulnar nerve between 2001 and 2005 were evaluated retrospectively; mean follow-up was 13.5 years. Elbow ROM was measured as flexion arc, flexion, and extension preoperatively and at the final follow-up, and compared via a mixed analysis of variance adjusting for age. Neuropathy was assessed preoperatively using a modified McGowan neuropathy grade and postoperatively using modified Wilson-Krout criteria. An ordinal logistic regression analysis used postoperative modified Wilson-Krout criteria as the outcome and preoperative factors as predictors. RESULTS Preoperative McGowan grades were Grade 1 in 14 patients (12.2%), Grade 2A in 28 (24.3%), Grade 2B in 53 (46.1%), and Grade 3 in 20 (17.4%) patients. Postoperatively, 66 patients (57.4%) had excellent results, 26 (22.6%) had good results, 16 (13.9%) had fair results, and 7 (6.1%) had poor results at the final follow-up, as per the Wilson-Krout criteria. There were no complications. Pre- and postoperative elbow ROM was significantly decreased in patients with previous trauma or surgery of the elbow compared with those without (P < 0.05). Anterior subcutaneous transposition of the ulnar nerve did not significantly affect elbow ROM regardless of previous trauma or surgical history nor preoperative ROM (P > 0.05), after adjusting for age. Patients with prolonged symptoms prior to surgery and worse neuropathy tended to have less satisfactory functional outcomes (P < 0.05), after adjusting for covariates. CONCLUSIONS Anterior subcutaneous transposition of the ulnar nerve is an effective and reliable treatment of cubital tunnel syndrome with satisfactory outcomes and minimal effect on elbow ROM.