BACKGROUND:
Although conservative treatment is a well-established method for treating nondisplaced and minimally displaced (< or =2 mm) fractures of the lateral humeral condyle in children, there is still great uncertainty concerning the rate and time course of subsequent displacement. Therefore, the appropriate frequency of radiographic follow-up remains unclear. The aim of the study was to determine the rate of subsequent displacement after conservative treatment of nondisplaced and minimally displaced fractures of the lateral humeral condyle in children.

METHODS:
A retrospective analysis of 51 consecutive patients with nondisplaced and minimally displaced fractures of the lateral humeral condyle was performed.

RESULTS:
Five fractures (9.8%) displaced within 5 days while immobilized and were safely detected by a follow-up radiograph within 1 week after trauma. Additional follow-up radiographs between the first and third weeks did not show relevant alterations in the fracture gap. Mean time of cast immobilization was 22 days, with a range of 17 to 34 days. No pseudarthrosis occurred.

CONCLUSION:
Fractures with less than or equal to 2 mm of displacement can probably be primarily treated safely by cast immobilization. Anteroposterior and lateral radiographs out of plaster between the fourth and sixth days are necessary to diagnose subsequent displacement of unstable fractures, whereas further "late" displacement did not occur.