Sonographic differentiation of stable and unstable lateral condyle fractures of the humerus in children.

Fractures of the lateral humeral condyle in children may cause difficulties in diagnosis and treatment. The fracture line involves the cartilaginous trochlea, which cannot be visualized on conventional radiographs. Therefore, a differentiation is not possible between the conservatively treated stable and the surgically treated unstable fracture, which involves the joint surface but is not dislocated primarily. We performed high-resolution ultrasonography in six children (age, 4-9 years) with a lateral condyle fracture of the humerus and uncertain joint involvement. Ultrasonography was able to visualize the fracture line through the joint surface in two children. Additional three-dimensional information could be gained that helped to plan further surgical procedures. The sonographic findings were confirmed intraoperatively and by magnetic resonance imaging in one child. In the remaining four children, ultrasonography was able to rule out joint involvement, thus classifying the fracture as stable. Conservative treatment was started, and the sonographic findings were confirmed by radiographs 4 days after the trauma to rule out secondary displacement. High-resolution ultrasonography is able to diagnose fracture involvement of the joint forming cartilaginous trochlea humeri in children, thus making further invasive or costly investigations such as magnetic resonance imaging unnecessary.