Background: Lateral condyle humerus fracture nonunion after surgical fixation has been reported to be <1%. The purpose of this study was to evaluate the rate and risk factors for delayed healing of pediatric lateral condyle fractures after surgical fixation.
Methods: Retrospective study of all operatively treated lateral condyle fractures at a single institution from 2006 to 2013 was performed. Radiographic evaluation included: measured fracture displacement at both presentation and after surgical fixation, fracture classification, and multiple parameters of pin configuration. Patients who had delayed healing were defined as those not healed by the eighth week of follow-up and were compared with those fractures that healed in <8 weeks to identify risk factors associated with delayed healing. Purposeful selection was utilized to identify factors for entry into a multivariate binary logistic regression model.
Results: A total of 210 children were evaluated. Mean follow-up was 25 weeks (4 wk to 5 y). Distribution of Weiss classification was as follows: type 1, 8 (4%); type 2, 61 (29%); and type 3, 141 (67%). There were 33 (16%) delayed unions and 7 of these (3% of the entire cohort) required further surgery to achieve healing. Weiss classification, intraoperative fluoroscopy time, and intraoperative displacement after fixation met criteria for entry into the regression. While Weiss classification did not remain significant within the model, its removal resulted in a 30% change in the parameter estimate for intraoperative fluoroscopy time. For each second increase in fluoroscopy time, there is a 3% increase in the risk of delayed healing. Patients with >1 mm displacement of the lateral cortex after fixation had an increased risk of delayed healing (OR=4.78, P=0.007).
Conclusions: Delayed union of lateral condyle fractures is a matter of concern, and the rate of secondary surgery to achieve healing appears to be higher than previously reported. Risks for delayed healing include amount of residual displacement after reduction and the difficulty in attaining that reduction, as defined by fluoroscopy time.
Level of evidence: Level IV-therapeutic study, case series.