Objective: Cubital tunnel syndrome is the second most frequent nerve entrapment syndrome in upper extremity. Among treatment options, in situ decompression is an effective and safe procedure. However, nerve stretching or subluxation is a potential problem. In this study, we want to identify in situ decompression with cubital tunnel retinaculum repair that can relieve ulnar nerve stretching. Materials and Methods: In total, 35 patients (30 male, 5 female; mean age, 53.1 years) presenting with primary cubital tunnel syndrome operated by in situ decompression with cubital tunnel retinaculum repair were included in the repair group. Twenty-six patients (19 male, 7 female; mean age, 54.6 years) treated with in situ decompression were included in the control group. Intraoperatively in the repair group, the ulnar nerve length (UNL) from intermuscular septum to the first motor branch was measured before and after the cubital tunnel retinaculum repair. Ulnar nerve position at elbow extension and flexion was recorded by ultrasonography postoperative 1 year in both groups. The UNL before and after the retinaculum was analyzed by t test, and ulnar nerve position between the two groups was analyzed by Fisher’s exact test. Results: UNL at elbow extension was not different significantly before and after the retinaculum repair (before repair, 11.4 ± 0.7 cm; after repair, 11.4 ± 0.7 cm), but UNL at elbow flexion was significantly decreased after the retinaculum repair (P < .001; before repair, 12.5 ± 0.7 cm; after repair, 11.8 ± 0.7 cm). The ulnar nerve position at both extension and flexion was different between groups (P < .001). Conclusion: UNL was decreased after cubital tunnel retinaculum repair. In situ decompression with cubital tunnel retinaculum repair can be an effective procedure to relieve irritation due to ulnar nerve stretching.
