What is Distal Humerus Fractures?
Fractures of the lower part of the upper arm bone, or the distal humerus, account for roughly 2% of all fractures and a third of all upper arm bone fractures. These injuries happen mainly in two groups: younger men and older women. High-energy injuries like accidents are common among young people, while low-energy falls are more common among older individuals.
These fractures can be quite complex to treat because they can involve both the bone’s middle and its end, near a joint. In all cases involving a joint, it’s crucial to carefully realign the broken bones to minimize the risk of developing arthritis caused by the injury. This often requires surgery and a specific recovery plan to promote successful healing and prevent complications. These complications may include a stiff elbow, abnormal bone growth, and nerve damage.
What Causes Distal Humerus Fractures?
Fractures in the lower part of the upper arm bone, or the distal humerus, usually happen because of an injury to the elbow. This could occur if something hits the arm directly, like an object or the ground during a fall. More severe fractures often come from high-speed accidents like car or motorcycle crashes. Some of these fractures have even happened from bullets or other projectiles. It’s also important to note that the severity of the injury – whether it’s a low-energy or high-energy incident – often depends on the patient’s age.
Risk Factors and Frequency for Distal Humerus Fractures
These types of breaks or fractures are found most often in two different groups: younger males who get hurt due to sudden injuries and older women who fall and hurt themselves directly. Still, they’re not very common, making up just 2% of all fractures. They may be rare, but there seems to be a trend of them becoming more common. For instance, research by Pavlanen and his team showed that the number of such fractures increased five times from 1970 to 1998.
Signs and Symptoms of Distal Humerus Fractures
People with elbow problems generally experience pain and swelling in the area, leading to decreased movement of the elbow. Movements should be minimized due to the possibility of injuring nerves and blood vessels. This also necessitates a detailed check of nerves and blood vessels, including the following:
- Checking the sensory and motor functions of the arm, focusing on specific nerves like the median, radial, ulnar, anterior interosseous nerve (AIN), and posterior interosseous nerve (PIN)
- Examining the pulses away from the heart
- Examining the different muscle compartments of the forearm
As with any injury, there should also be a second examination to rule out any other injuries that might have been overseen due to the primary injury. In cases where the patient is unresponsive or under the influence, the doctor should look for signs like skin discoloration, cuts, or swelling to decide whether imaging tests are needed.
Testing for Distal Humerus Fractures
Imaging tests like X-rays and computed tomography (CT) scans play a crucial role in assessing possible elbow and arm injuries. When looking at the lower end of the upper arm bone (distal humerus), your doctor may ask for a straight-on (AP) and side view (lateral) X-ray of your elbow and upper arm. It’s often recommended that the AP X-ray be taken with your elbow bent at a 40-degree angle.
Notably, valid images of your whole forearm and upper arm are needed to double-check for any other injuries. Traction views, a type of X-ray where pulling forces are applied to the affected limb, can also help in offering a better look at specific fracture pieces.
If there’s a suspicion of a coronal shear fracture (a break in the bone transverse to the long axis) of the distal humerus, the most critical X-ray to get is the lateral or side view. On achieving a truly lateral view, the presence of the “double-arc sign” indicates a particular type of fracture that extends into the trochlea, part of the elbow joint.
CT scans can help plan surgical procedures, especially when a fracture has a shear component. They offer a 3D view of the fracture, allowing for a more extensive pre-surgical evaluation. Still, magnetic resonance imaging (MRI) usually isn’t necessary for immediate injuries.
When it comes to categorizing such fractures, there are different classification systems, namely the AO, Milch, and Jupiter systems. These systems categorize fractures into different types based on factors such as whether the joint is involved, the complexity of the fracture, and where it’s located.
Treatment Options for Distal Humerus Fractures
For treating bone fractures, doctors use a couple of methods. Sometimes, they use casts to keep the broken bone in place until it heals. This usually happens when the break isn’t severe or if the patient’s overall health makes surgery too risky.
More often, though, doctors surgically repair the fracture. One common method is open reduction internal fixation, which realigns the broken bones and uses metal plates to keep them in place. This method is typical for fractures that are displaced (where the broken ends of the bone aren’t lining up correctly).
Especially in older, inactive patients, doctors might choose to replace the entire joint instead of just fixing the broken bone. This procedure, called total elbow arthroplasty, has its limitations because artificial joints don’t last forever. So, this surgery is often reserved for those who can follow post-operative guidance like weight restrictions.
During surgery, the doctor usually approaches the fracture from behind the elbow. Various techniques can be used, such as splitting or moving aside the muscle at the back of the arm. An essential part of any method is finding and protecting the ulnar nerve, which runs near the elbow.
Most surgeons agree that the nerve needs to be visualized and kept safe during the operation. But they disagree on whether it’s better to move the nerve out of the way or only lessen the pressure on it during surgery.
When undertaking the surgery, it’s contentiously important to identify and protect the radial nerve, especially if a plate is required on the upper arm bone. It is usually around 10cm away from the elbow joint, and surgeons take special care not to injure it and often document its position relative to the fixation plate placement in their notes.
In some cases, they might approach the fracture from the side of the elbow, especially for specific kinds of fractures in the joint.
What else can Distal Humerus Fractures be?
- Dislocation of the joint between the collarbone and shoulder blade
- Dislocation of the shoulder joint accompanied by a break in the upper end of the arm bone
- Fracture of the elbow
- Broken collarbone
- Cracked shoulder blade
- Imperfect arm bone around the knob-like structure (greater tuberosity) located near the shoulder
- Dislocation of the joint between the collarbone and breastbone
- Emergency treatment of a dislocated shoulder
- Emergency management of a broken shoulder blade
Possible Complications When Diagnosed with Distal Humerus Fractures
Elbow stiffness can be a result of any injury to the elbow, mainly when it is kept immobile for extended periods. That’s why most doctors prefer an early, rigid fixation for fractures in the distal humerus (lower arm bone near the elbow). This treatment allows for exercises to restore the range of motion soon after the operation, usually beginning within 14 days.
Nerve injuries, particularly of the ulnar nerve, can also occur frequently due to their closeness to the broken fragments and the necessity to move and pull back the nerve during fixation. This can sometimes lead to a temporary nerve weakness that may recover but can also lead to lasting deficiencies.
Heterotopic ossification, or the abnormal growth of bone in non-skeletal tissues, can be a complication after the operation. It often happens in severe trauma cases. Individuals who have Type A and B distal humerus fractures, floating elbow injuries, or a delayed surgery are at a higher risk.
The risk for nonunion, which is the failure of the bone to heal correctly, is relatively low for distal humerus fractures, but it can occur. If the surgeon opts to utilize an olecranon osteotomy (a surgical procedure on the elbow), there’s also a risk for non-union. Key factors associated with nonunion include smoking, obesity, and diabetes. If nonunion occurs, it can usually be treated by revising the operation and using a bone graft.
Possible complications and risks:
- Elbow stiffness due to immobilization
- Nerve injury, especially of the ulnar nerve
- Heterotopic ossification or abnormal growth of bone in non-skeletal tissues
- Nonunion or failure of the bone to heal correctly
- Non-union of an olecranon osteotomy site if applied
- Risks factors for nonunion like smoking, obesity, and diabetes
Preventing Distal Humerus Fractures
If someone fractures their distal humerus, the bone near their elbow, they should know that surgery is often needed to fix it. These types of fractures, especially those covering a major joint, can have long-term effects even after the bone has healed. It’s very useful for patients to understand this from the start to avoid any confusion later. It’s also crucial that patients begin moving the joint early after surgery to boost their chances of recovering successfully.
During the immediate treatment, patients can expect a thorough examination, any necessary scans, and a temporary splint for support. If the fracture is closed and there are no other injuries, the patient might go home and schedule a follow-up appointment soon after to discuss surgical options with an orthopedic surgeon. However, if it’s an open fracture or if there are multiple injuries, hospital admission could be necessary.
If there’s also a nerve injury, patients should realize that this could be caused by swelling or strain from the fracture and might only be temporary. However, nerve injuries can take several months to go away and usually don’t require immediate treatment.
