Distal humeral fracture means that the bottom of the upper arm bone is broken. Since the humerus forms the upper half of the elbow, this type of fracture certainly affects the elbow. Displaced means the bone is not only broken, but the fracture has separated. These fractures are complex and challenging to treat. Surgery is usually required.
This orthopedic injury is complex, multifactorial, and definitely challenging. The surgical choices are usually: 1) internal fixation, 2) external fixation, and 3) total elbow replacement. Each of these choices has its own indications (when to use them), advantages, and disadvantages.
One of the ways surgeons have of evaluating which approach to use is to examine the results from other patients who were treated with one approach versus another. The way to evaluate this is to look back at the results other patients had with this type of injury using X, Y,or Z treatment. Results referred to as outcome measures include elbow range-of-motion, return of normal muscle strength, function, bone healing, and quality of life.
In a successful case, the joint should be stable yet move freely. Length of time in the hospital and in rehab along with the associated costs might also be factored in when evaluating success versus failure. Complications such as infection, poor wound healing, and nonunion (failure of the bone to heal) are recorded. Implant failure (usually from loosening) and revision surgery are two other possible problems that surgeons keep track of as a way to evaluate the final results. Here’s what the evidence suggests from reviews of current research.
Internal Fixation. Internal fixation refers to an open procedure where the surgeon puts the bones back together and holds them in place with wires, metal plates, and/or screws. This is the most commonly used operation. Many decisions come into play with this approach. The surgeon sizes up the injury and decides how best to get into the joint: from the back of the elbow (posterior or from the sides? If it seems best to make the incision from the side, then which side: medial (side closest to the body) or lateral (side away from the body)?
Studies show that the posterior approach gives the surgeon a full view of both sides of the elbow but in order to get to the joint, it’s necessary to cut through the triceps muscle and take a chunk of bone out. Removing a wedge-shaped piece of bone for this approach is called an osteotomy. Anytime an osteotomy is done, there is an increased risk that the bone won’t knit back together nicely. The result would be a nonunion of the bone where the osteotomy was done.
As technology and surgical technique improve, new contoured plating with different shapes to choose from and locking screw techniques have become available. Researchers are just beginning to study and report on the results using these various options. Measurements of the healing site strength and stiffness as well as bending forces are under investigation when the various plating systems are placed in different locations and angles (called the configuration). For example, the surgeon may use a Y-shaped plate or the orthogonal plate and place them perpendicular (at a right angle to each other) or in parallel (one on each side of the joint).
Most of these studies are being done on cadavers. The bone strength can be tested until it breaks to determine the upper limit of force each configuration can withstand. Using cadavers with osteoporosis makes it possible to also study the results of fixation on patients with poor bone quality. Results using different length of screws and strength of the bone-to-screw interface are also being compared.
What they’ve found so far is that locking plates may work better than standard plates. And failure is more likely as a result of the bone-implant interface, not because the hardware itself breaks. There isn’t enough data yet to say at what bone mineral density results will be successful. More study is needed before this information will be available.
External Fixation. Like internal fixation, some type of rigid support is needed to hold the bones together during the healing. But instead of being inside the body and unseen, external fixation consists of pins placed through the skin and soft tissues into the bones with metal rods between them. The rods remain outside of the arm. External fixation is used when the fracture is displaced (separated) and poking out through the skin. The surgeon must get the bones lined back up and keep them there until healing takes place but is unable to do so from the inside. That’s where the external support can be helpful.
Elbow Replacement. If the patient doesn’t have strong enough bones to hold the hardware needed for fixation, then a joint replacement may be needed. The same is true if the joint surface has been too damaged to fix or repair. Older adults and/or patients who have had a failed internal fixation procedure may also qualify for a total elbow replacement.
Results from studies of elbow replacement for distal humeral fractures show good-to-excellent results for the majority of patients (85 per cent). Outcomes are better when the surgery is done right away as opposed to being delayed for a time. Complications such as nerve injuries, infection, implant loosening, and chronic pain are reported in 22 per cent of all cases studied. The use of elbow replacements may expand as surgeons are able to reduce the complication rates. Improved surgical techniques, better implant designs, and improved ways of cementing the implant in place may help move this along.