Lateral humeral condyle fracture most commonly occurs for ages 5-10. It takes up to 20% of paediatric elbow fractures and is the second most common fracture of the lateral humeral condyle among children after supracondylar fracture.
Usually a displaced fracture, lateral humeral condyle fractures are classified into types based on the severity of the fracture line. To know the type of fracture, examination has to be done by a radiograph, CT scan or MRI.
Type I: Less than 2mm displacement
Type II: 2-4mm displacement
Type III: Completely displaced with rotation
There are two mechanisms that result in the fracture. The pull-off theory is when the lateral condyle tears away, usually caused by pulling of the extensor muscle. The push-off theory happens when the impact of a fall hits an outstretched arm, causing the radial head to push into the lateral condyle.
There are certain difficulties in diagnosing the injury. If the bones are not yet ossified, which only happens at age 9-10, the child may be more susceptible to this kind of fracture and it is difficult to diagnose. Though the patient experiences lateral pain in the side of the elbow, the fracture line might not be apparent until 7-10 days after being injured.
Late diagnosis is not uncommon. The fracture line might not be clearly visible on the radiograph. Usually several radiographs have to be done before determining if the fracture is displaced or non-displaced. A late diagnosis could reduce the chance of recovery after surgery and increases the risk of avascular necrosis.
Type I fractures with minimal displacement may be treated without surgery. The arm is immobilized in a cast for 3-4 weeks with close follow-up in case of late displacement or malunion. If the fracture is not well taken care of during the period of immobilization, the bones might be further displaced or not completely jointed. A surgery might be necessary then.
Type II and III fractures have to be treated with surgical methods, usually an open reduction and fragment stabilization. For this technique, K-wires are placed to stabilize the anatomic reduction and two pins are laterally inserted. The arm is then immobilized in a cast for 4-6 weeks.
The risk of complications is generally low with a good chance of full recovery. However, patients will most likely retain scars or abnormal appearance of the elbow shape.