Factors Associated with Failed Closed Reduction in Flexion and Gartland Type III Pediatric Supracondylar Humerus Fractures.

Background: Most displaced supracondylar humerus fractures (SCHFs) are treated with closed reduction and percutaneous pinning. While there are only a few possible indications for converting to an open reduction, a failed closed reduction is a common cause. This study aims to elucidate possible risk factors for failed closed reductions of SCHF. Methods: A retrospective review of SCHF from 2010 to 2020 at a pediatric tertiary medical center, which underwent operative fixation, was conducted. Exclusion criteria were open fractures and reasons for open reduction other than failed closed reduction. Rates of open reduction were assessed by preoperative fracture classification and assessed for respective associations with the factors of interest using Student's t-test, χ Results: Seven hundred sixteen patients (age range 1-15 years old) met the inclusion criteria. Failed closed reductions were more likely in flexion-type fractures (15/37) compared to type III extension fractures (31/480) (OR: 9.88, 95% CI: 4.66-20.92). For flexion-type fractures, failed closed reduction occurred at a lower rate for anteriorly displaced fractures (5/22) when compared to other displacement directions (10/15) (OR: 0.15, 95% CI: 0.034-0.637). Age, race, social deprivation index, BMI, associated injuries, comminution, and nerve palsy were not significant. For type III extension fractures, older age (>8 years) (OR: 5.22, 95% CI: 1.56-17.43) and nerve injury (OR: 2.23, 95% CI: 1.00-5.10) were associated with failed closed reduction. No other factors of interest were significant. Conclusions: Flexion-type SCHFs have significantly higher rates of failed closed reduction compared to extension-type fractures. For flexion-type fractures, anterior displacement predicts a lower rate of failed closed reduction compared to other displacement directions. For type III extension fractures, risk factors include older age and a nerve injury on preoperative exam. Key concepts: (1)Most operative supracondylar humerus fractures (SCHFs) can be treated with closed reduction and percutaneous pinning.(2)Surgeons need to be aware of possible reasons for having to convert to open reduction of pediatric SCHFs.(3)Flexion-type fracture patterns had a higher rate of an open procedure compared to extension-type fractures.(4)Patients who sustained an extension-type injury were more likely to require an open reduction if they had a nerve injury or were older at the time of injury or pinning (>8 years old). Level of Evidence: III, Retrospective Cohort Study.