5 Things You Need to Know About Distal Humerus Fractures

1. Children tend to get supracondylar and lateral condyle fractures.

As with most upper extremity fractures, distal humerus fractures tend to happen with a fall on an outstretched arm. Typically, the force of the impact is transmitted up the forearm and breaks the humerus through the very thin supracondylar region. Most times, the force will go directly across the bone and stay out of the joint. However, sometimes the fracture line extends into the joint and involves the entire lateral condyle. Medial condyle and medial epicondyle fractures are much less common.

2. Most of these fractures can be treated with a cast.

If the fracture is stable and in satisfactory alignment, a long arm cast is placed extending above the elbow. Because children tend to rapidly lay down new bone and stabilize the two pieces, these fractures usually heal within 6 weeks.

3. Some fractures need to be pinned.

When the fracture is severely displaced, or if it causes incongruity of the joint surface, the fracture should be pinned. Most times, the bones can be realigned without making an incision (closed reduction), and then held in place with pins sticking through the skin (percutaneous pinning). The pins are usually removed in the office in 3 to 6 weeks. With lateral condyle fractures extending into the joint, it is very important to ensure the joint surfaces line up. Especially in younger kids, not all of the bone is ossified and the cartilage portions cannot be seen under x-ray. An arthrogram may need to be done. This involves placing radiopaque dye (which is visible on x-ray) into the joint to coat the surface of the cartilage. This allows the surgeon to visualize the alignment of the fracture, before placing the pins.

4. Adults almost always require surgery.

In adults, these fractures are usually unstable. The distal humerus is shaped like a spool of thread balancing on the end of a stick through a very thin area (olecranon fossa). When the bone breaks, metal plates are required to reconnect the spool and the stick. Two plates are usually required.

5. Since there is very little surface area between the two pieces, these fractures tend not to heal.

Sometimes, even with the surgeon's best efforts, the fracture does not heal (non-union). At this point, options are pretty limited. There may be another attempt at fixing the fracture. Other times, an elbow replacement may be an option. In a patient who is not a candidate for an elbow replacement, an elbow fusion may be considered.