Incidence, Risk Factors, and Definition for Nonunion in Pediatric Lateral Condyle Fractures.

INTRODUCTION: Lateral condyle fractures are a common pediatric elbow injury. Nonunion is a known complication of this injury but its incidence and causative risk factors are unknown. Further, a clear and consistent definition of nonunion for pediatric lateral condyle fractures does not exist. The purpose of this study is to determine the rate of nonunion, the risk factors associated with it and to provide a clear definition.

METHODS: A retrospective chart review of all pediatric lateral condyle fractures treated at an urban, tertiary pediatric care center between 2001 and 2014. Data collected included demographics, Weiss classification, type of treatment, follow-up, time from injury to surgery and complications. For patients with nonunions, additional treatments and final range of motion were also recorded. A nonunion was defined as lack of callus with fragment migration by 8 weeks after initiation of treatment.

RESULTS: A total of 530 patients were identified of which 500 were available for review. There were 7/500 (1.4%) nonunions in the cohort. Nonunion occurred in 1.4% (2/140) of type I fractures, 0% (0 /178) of type II fractures, and 3% (5/168) of type III fractures. The only significant risk factor for nonunion was the presence of a type III fracture (P=0.05). Five patients with nonunion underwent revision surgery with a partially threaded cannulated cancellous screw. All of these patients went on to union. Four of the 5 patients had their screws removed after union.

CONCLUSION: Nonunion after pediatric lateral condyle fracture is rare and is defined by lack of any callus with fragment migration at 8 weeks. The only significant risk factor for nonunion development was the presence of a type III fracture. Revision surgery with a partially threaded screw achieved union in all cases.

LEVEL OF EVIDENCE: Level IV-retrospective case review.