This paper reports the outcome and complications of a lateral condyle fracture of the humerus in children treated by the fine classification of Jakob stage.

Forty-five cases of a lateral condyle fracture of the humerus in children were treated according to the fine classification of the Jakob stage. There were 4 cases of Jakob stage Ia fractures treated with the application of a simple cast; 16 cases of Jakob stage Ib & IIa fractures treated with a closed reduction and k-wire pinning; and 25 cases of Jakob stages IIb & III fractures treated with an open reduction and K-wire pinning. The average follow-up period was 25 months.

Postoperative complications were seen in 18 cases. As minor complications, there were 2 cases of delayed union, 5 cases of hypertrophy of the lateral condyle and 10 cases of osteophyte formation. As major complications, 1 case of avascular necrosis and limitation of motion developed. There were no serious complications such as nonunion, malunion, ectopic ossification, early arrest of the growth plate, and nerve injury. The clinical outcomes were excellent in all but one case of a joint motion limitation.

The fine classification of the Jakob stage is effective in determining the treatment method for lateral condyle fractures of the humerus in children.