To assess the clinical results of surgical treatment for established nonunion of the lateral humeral condyle and to determine the factors necessary for successful outcome.

12 patients with nonunion of the lateral humeral condyle underwent open reduction, autogenous iliac bone graft and internal fixation with two smooth or treated K-wires between 1994 and 1999. Mean age was 16 years and the mean follow-up period was 2 years and 8 months.

All of the patients achieved solid union at the nonunion site and were free of pain in the elbow upon strenuous activities. Average union time was 7.2 weeks after the surgery. Aggressive anatomical reduction of the fragment must not be undertaken because it may disturb a well adapted joint congruity in adults. Rigid internal fixation with iliac bone graft and preservation of the blood supply of the distal fragment are important factors for a successful outcome. The range of motion of the elbow joint decreased 10.5 ° on average after surgery. Valgus deformity improved in four of six patients.

The patients with symptomatic established nonunion are good candidates for surgery, even adults.