Prevalence of ulnar nerve palsy with flexion-type supracondylar fractures of the humerus

The aim of this study is to report the rate and type of neurologic injury associated with flexion supracondylar fractures at a tertiary, university institution treated over a 10-year period. All supracondylar humerus fracture cases treated at our institution between January 2004 and January 2014 were retrospectively reviewed. Twenty-three flexion-type fractures were identified. Patient demographics as well as fracture classification, treatment modalities, and pre-and post-treatment neurologic status were analyzed. Twenty-three flexion-type supracondylar humerus fractures were identified and reviewed out of a total of 1000 supracondylar humerus fractures (2.3%). Details of the patients' neurologic status upon presentation demonstrated that 17 (74%) patients were intact and six (26%) patients presented with an ulnar neuropraxia. Zero type I fractures, one type II fractures (14.3%), and five type III fractures (33.3%) demonstrated an ulnar nerve palsy. Of these, all six nerve deficits resolved following treatment. One additional patient was identified with median nerve neuropraxia following treatment with closed reduction casting, which resolved following observation. A total of 4 (17.4%) patients were treated with closed reduction casting, 15 (65.2%) with closed reduction percutaneous pinning, and four (17.4%) with open reduction internal fixation. Flexion-type supracondylar fractures of the humerus are rare yet significant injuries. The 26% of patients who developed an ulnar neuropraxia following a displaced flexion supracondylar fracture were higher than previous studies reported in the literature. This increased prevalence may be due to the high rates of type III fractures reported in the current study. Level of evidence: III, Retrospective comparative cohort analysis.