Lateral Condyle Fractures
Classified by Milch into I and II based on how far medially the fracture exits.
– If it exits medial to the trochlear groove – no lateral buttress for the ulna & it may dislocate laterally (Milch II).
– If it exits lateral to the trochlear groove – ulna will be buttressed by the trochlea and will not dislocate (Milch I).
So when you see the elbow injury in which the capitellum, radius, and ulna are all displaced with respect to the distal humerus consider Milch II lateral process fracture or distal humeral physeal fracture. Then look at where the radius and ulna are – usually, in elbow dislocations, the radius and ulna are off laterally. In a distal humeral physeal injury, they are usually off medially.
If the radius and ulna are still articulating with the humerus, but the relationship between the radius and capitellum is off and the capitellum doesn’t look like it is in the right place with respect to the distal humerus, think lateral process fracture (Milch I)
The Milch I fractures can go right through the ossified capitellum – a Salter IV fracture
The Milch II fractures typically go through the cartilaginous trochlea – a Salter II fracture
Type I – undisplaced, incomplete fracture (hasn’t gone through the cartilage yet)
Type II – minimally displaced, complete fracture
Type III – completely displaced.
Treatment – open reduction internal fixation of II and III; must see inside the joint to judge the reduction (because it is cartilaginous!)
Kocher lateral approach. Minimize the soft tissue stripping.