Anterior transposition and positioning via helix sling method in cubital tunnel syndrome: An open-label, retrospective trial of maximum 5-year follow-up.

Background: Ulnar nerve transposition is used for cubital tunnel syndrome (CuTS) with nerve instability. The aim is to report a modified technique for ulnar nerve transposition using medial intermuscular septum and Osborne's ligament as a double-strand helix sling to recreate a sliding channel for the ulnar nerve and the functional outcomes at follow-ups. Methods: Twenty-five patients with persistent CuTS underwent nerve release and subcutaneous transposition from January 2017 to January 2022 in our institute. Among them, 9 patients were excluded due to incomplete medical records, lack of follow-up history, or bilateral limb numbness. The medial intermuscular septum with one end attached was excised to rebuild a tension-free double-strand helix sling by anchoring at the residue of Osborne's ligament. The modified Mc-Gowan classification was applied to evaluate the disease severity preoperatively. The quick disability of arm and shoulder and hand (quickDASH) questionnaire and visual analogue scale (VAS) scores were used to evaluate pre- and postoperative symptoms. Ultrasound imaging was utilized for nerve structure evaluation before surgery and at follow-ups. Results: Sixteen out of twenty-five patients received follow-ups postoperatively (ranging from 9 to 69 months, 36 months in average). No findings indicated subluxation of ulnar nerve or recompression by ultrasound imaging examination. According to quickDASH and VAS scores and physical examination, 14 out of 16 patients showed postoperative improvement in symptoms and function at final follow-ups. Interpretation: In this modified technique, the medial intermuscular septum and Osborne's ligament can create tension-free helix sling for stable and smooth sliding and preventing subluxation after nerve transposition, which is highly effective and safe for CuTS treatment.