Medial condyle fracture of the distal humerus in an adolescent with pre-existing fishtail deformity. A case report.

Medial condyle fractures of the humerus are rare in any age group. We report a unique case of a humeral medial condyle fracture in a 15-year-old boy with posttraumatic fishtail deformity. The fracture line extended up from the top of the sharp trochlear wedge to the incomplete medial supracondylar cortical aperture. The appearance of the upward displacement and computed tomography imaging with three-dimensional reconstruction at the two different elbow positions suggested that an edge of the semilunar notch of the olecranon acted as a wedge to break and split the trochlea directly. This is the first visualized case of a wedge type injury and may provide evidence that humeral medial condyle fractures can be produced by the wedge force besides the valgus avulsion one.