A New Classification System Predictive of Complications in Surgically Treated Pediatric Humeral Lateral Condyle Fractures

Background: The most commonly cited classification system for lateral condyle fractures (Milch) has not been shown to be predictive of outcome or recommend treatment. Purpose: To determine whether a classification system and treatment based on fracture displacement and articular congruity correlates with the complication rate after pediatric lateral humeral condyle fractures. Methods: A retrospective review of all children with lateral condyle fractures treated operatively at one institution from 1996 to 2003 was performed. All fractures were classified by the following system: A Type I fracture is displaced less than 2 mm. In a Type II fracture there is >= 2mm of displacement with intact articular cartilage, as demonstrated by arthrogram (65 patients). In a Type III fracture there is >= 2mm of displacement and the articular surface is not intact (93 patients). The 158 patients with types 2 and 3 fractures underwent surgery and are the focus of this study. Complication rates were compared between groups 2 and 3, and with regard to patient age, length of time between injury and surgery, and duration of casting. Results: The overall complication rate was 25% (39 of 158). The most common complications included radiographic and/or clinical bump (16 of 158 or 10%), and infection treated with oral antibiotics (4 of 158 or 2.5%). There were 6% major complications (10 of 158) defined as those with presumptive long-term effects or requiring reoperation, including 1 nonunion (0.6%). There were no acute complications at the time of injury or surgery. If lateral bump is excluded as a complication, then the overall complication rate is 14.6% (23 of 158). The overall complication rates for types 2 and 3 fractures were statistically significantly different (P < 0.03): 11% (7 of 65) for type 2 and 34% (32 of 93) for type 3 fractures. Major complication rates were 1.5% (1 of 65) for type 2 fractures and 10% (9 of 93) for type 3 fractures, whereas minor complications occurred in 9% (6 of 65) of type 2 fractures, and 25% (23 of 93) of type 3 fractures (P = 0.03). There was no correlation between complication rate and patient age, number of days between fracture and surgery (all patients were treated within 16 d of their fracture), or duration of casting. We found that all 65 patients with Type II fractures had < 4mm of fracture displacement on pre-operative radiographs, and all fractures Type III fractures had >= 4mm of displacement. This may aid in predicting which fractures can be treated with closed pinning prior to an operative arthrogram. Conclusions: This is the largest series of operatively treated lateral condyle fractures reported in the literature. This classification system and treatment based on fracture displacement and articular congruity predicts the risk of complications, which were more than 3 times as likely to occur in type 3 fractures as type 2 fractures.