Factors Affecting Lateral Overgrowth in Operatively Treated Lateral Condyle Fractures in Children

Background: The most frequent sequelae of pediatric lateral condyle fractures is lateral condyle overgrowth (LCO). The purpose of our study was to investigate LCO in relation to age, quality of reduction, type of fixation, and fracture displacement. Methods: We retrospectively analyzed operatively treated lateral condyle fractures in children. The percent change in interepicondylar width (IEW) ((final − initial)/ initial x 100) was used to quantify LCO. IEW was measured from the medial and lateral epicondyles of the distal humerus, using the AP radiographs taken at admission (initial) and follow-up visits (final). The Song classification was used to classify fractures. Fixation was classified as pins, screws or both. The quality of reduction was defined as anatomic or nonanatomic (>2 mm of displacement). Patients were stratified into mild (0% to 10% overgrowth), moderate (10% to 20% overgrowth), and severe (>20% overgrowth) subgroups for further analysis. Results: Two hundred one patients were included in the study with an average time between initial and final radiograph measurements of 11.32 weeks. There was an average 11.84 %LCO. Using multivariable analysis, three variables demonstrated significant, independent associations with %LCO: age, race, and quality of reduction. Increasing age remained inversely associated with %LCO. Compared with White patients, Black and Asian patients had significantly greater %LCO. Patients with nonanatomic reductions had a significantly greater %LCO compared with anatomic reductions. When patients were stratified into mild, moderate, and severe groups, age in the mild group, nonanatomic reduction in the moderate group, and race in the severe group were found to be independently associated with increased %LCO using multivariable analysis. Conclusions: The amount of LCO was found to be related to nonanatomic reduction, younger age, and Black and Asian race. Interestingly, it was not related to the amount of initial displacement or type of hardware used. To date, this is the largest study investigating LCO in surgically treated lateral condyle fractures. Level of Evidence: Level III—retrospective cohort study.