Ulnar Nerve Neuropathy After Surgery for Intraarticular Distal Humerus Fractures: An Analysis of 116 Patients.

ABSTRACT

PURPOSE: To identify the incidence and the factors associated with a postoperative ulnar nerve neuropathy in patients who had undergone open reduction and internal fixation for intraarticular distal humerus fractures. METHODS: We retrospectively reviewed 116 patients who had undergone surgery between January 2011 and December 2020. Age, sex, BMI, mechanism of injury, open or closed fracture, operation time, tourniquet time, and nerve injury at the final examination were collected from medical charts. We essentially used the paratricipital approach. In cases in which the reduction of intraarticular bone fragments was difficult, olecranon osteotomy was used. Ulnar nerve function was graded according to a modified system of McGowan. We conducted logistic regression analysis to investigate factors of neuropathy using items identified as statistically significant in univariate analysis as explanatory variables. RESULTS: Thirty-four patients (29.3%) had persistent neuropathy at the final follow-up. In the modified McGowan classification, 28 patients had grade 1 and 6 patients had grade 2 neuropathy. Olecranon osteotomy emerged as a distinct explanatory variable for the prophylaxis of ulnar nerve neuropathy in the multivariate analysis (odds ratio, 0.30; 95% confidence interval, 0.12-0.73). Anterior transposition, however, was not a statistically significant factor (odds ratio, 1.91; 95% confidence interval, 0.81-4.56). CONCLUSIONS: Olecranon osteotomy was the only independent factor associated with preventing the occurrence of ulnar nerve neuropathy. Ulnar nerve transposition might not be associated with prevention of ulnar nerve neuropathy. TYPE OF STUDY/LEVEL OF EVIDENCE Prognostic IV.