[Incidence and risk factors of ulnar nerve dysfunction after open reduction and internal fixation of humeral intercondylar fractures].

ABSTRACT

Objective: To investigate the incidence and related risk factors of ulnar nerve dysfunction after open reduction and internal fixation of humeral intercondylar fractures. Methods: A total of 168 patients who underwent open reduction and plate and screw fixation of a humeral intercondylar fracture between January 2013 and May 2017 were retrospectively analyzed. There were 85 males and 83 females, aged from 14 to 77 years with a mean age of (43±17) years. Diagnosis of ulnar neuropathy was defined as documentation of sensory and motor dysfunction of the ulnar nerve in the medical record. The explanatory (independent) variables included age, gender, injury type, AO typing, time from injury to surgery, surgery approach, plates fixation methods and whether the nerve was transposed. Univariate and multivariate analyses were performed to determine risk factors associated with postoperative ulnar nerve dysfunction. Results: Acute injury-related ulnar nerve neuropathy was diagnosed in 12(7.1%) of 168 patients. Among the other 156 patients without preoperative ulnar nerve neuropathy,the total postoperative ulnar neuropathy was found in 52 patients (33.3%), and in 26(16.7%) at the final follow-up, according to the McGowan grades system; 23(88.5%) of 26 patients were clinically graded as grade 1, and 3(11.5%) were graded as grade 2. Multivariate logistic analysis showed that triceps sparing approach (OR=2.639, P=0.039) and parallel double plate fixation (OR=3.089, P=0.046) were associated with a risk of postoperative ulnar nerve dysfunction. Conclusion: There is a substantial incidence of postoperative ulnar nerve dysfunction after open reduction and plate and screw fixation of humeral intercondylar fracture, postoperative ulnar neuropathy may occur from the time of injury through the long-term follow-up period, triceps sparing approach and parallel double plate fixation are the risk factors for ulnar neuropathy.