Postoperative displacement as a predictor of early elbow motion limitation following fixation of pediatric lateral condyle fractures.

Purpose: Recovery of elbow motion is a primary concern following fixation of pediatric lateral condyle fractures, yet the influence of postoperative displacement on early motion outcomes remains unclear. This study aimed to evaluate the association between postoperative displacement magnitude and early elbow motion limitation. Methods: We retrospectively reviewed 63 pediatric patients (mean age 5.4 years) who underwent surgical fixation for lateral condyle fractures between 2015 and 2025. Immediate postoperative displacement was measured on postoperative radiographs. Early elbow motion limitation was defined as ROM <140° within the first year. Multivariable logistic regression identified independent predictors, and ROC curve analysis determined the optimal displacement threshold. Results: Twelve of 63 patients (19.0%) demonstrated early elbow motion limitation. This group had significantly greater postoperative displacement (1.53 ± 0.72 mm vs. 0.79 ± 0.62 mm, p = 0.002) and older age (6.5 ± 2.1 vs. 5.2 ± 2.1 years, p = 0.038) than the normal ROM group. Multivariable regression identified postoperative displacement as the sole independent predictor (OR 5.95; 95% CI 1.44-24.56; p = 0.014). ROC analysis demonstrated moderate predictive ability (AUC = 0.782). Using a 1.0 mm cutoff, early motion limitation was significantly more frequent in patients with displacement ≥1.0 mm than <1.0 mm (32.3% vs. 6.3%, p = 0.011). Conclusions: Immediate postoperative displacement independently predicted early elbow motion limitation after lateral condyle fracture fixation. A threshold of approximately 1.0 mm may serve as a practical reference for anticipating early motion recovery. Minimizing residual displacement may be beneficial, though longer follow-up studies are warranted.