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 t rochlea, which cannot be visualized on conventional radiographs. Therefore, a differentiation is not possible between the conservatively treated stabl e and the surgically treated unstable fracture, which involves the joint su rface but is not dislocated primarily. We performed high-resolution ultraso nography in six children (age, 4-9 years) with a lateral condyle fracture o f the humerus and uncertain joint involvement. Ultrasonography was able to visualize the fracture line through the joint surface in two children. Addi tional three-dimensional information could be gained that helped to plan fu rther surgical procedures. The sonographic findings were confirmed intraope ratively and by magnetic resonance imaging in one child. In the remaining f our 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 tr auma to rule out secondary displacement. High-resolution ultrasonography is able to diagnose fracture involvement of the joint forming cartilaginous t rochlea humeri in children, thus making further invasive or costly investig ations such as magnetic resonance imaging unnecessary.