Nonunions (Fractures that have not healed)
Most broken bones (fractures) heal without major issues. Occasionally, some fractures do not heal even when they get the best surgical or nonsurgical treatment. In some cases, certain risk factors make it more likely that a bone will fail to heal such as smoking, medications, and/or some medical conditions such as diabetes. When a broken bone fails to heal it is called a “nonunion.” A “delayed union” is when a fracture takes longer than usual to heal. Most bones heal within 4-6 months.
For bone healing to happen, the bone needs adequate stability, vascular (blood) supply, and a healthy patient. Good nutrition also plays a role in bone healing.
• Stability. Fractures must be put in a stable position that allows them to heal appropriately. Some fractures can be held in position with a cast or with surgical stabilization including a plate and screws, intramedullary nail (rods), or an external fixator.
Blood supply. Blood delivers the essentials required for fracture site healing. These essentials include oxygen, cells, and the body’s own chemicals necessary for healing (growth factors). The blood supply to the injured bone usually comes back on its own during the healing period.
• Nutrition. A broken bone also needs adequate nutrition to heal. Eating a healthy and well-balanced diet that includes protein, calcium, vitamin C, and vitamin D is the best way to ensure adequate nutrition.
Causes of Nonunions
Nonunions happen when the bone lacks adequate stability, blood flow, or has other medical reasons that have inhibited full healing. Nonunions may also occur in severely injured limbs that have been compromised of bony fragments, muscle tissue, and/or blood supply.
Several factors increase the risk of nonunion.
• Use of tobacco or nicotine in any form (smoking, chewing tobacco, and use of nicotine gum or patches) inhibits bone healing and increase the chance of a nonunion
• Older age
• A low vitamin D level
• Poor nutrition
• Some medications
• Medications including anti-inflammatory drugs such as aspirin, ibuprofen, and prednisone.
• A complicated break that is open or compound
Nonunions are more likely to happen if the injured bone has a limited or injured blood supply.
• Some bones, such as toe bones, have inherent stability and excellent blood supply. They can be expected to heal with minimal treatment.
• Some bones, such as the upper thighbone (femoral head and neck) and small wrist bone (scaphoid), have a limited blood supply. The blood supply can be destroyed when these bones are broken.
• Some bones, such as the shinbone (tibia), have a moderate blood supply, however, an injury can disrupt it. For example, a high-energy injury can damage the skin and muscle over the bone and destroy the external blood supply. In addition, the injury can destroy the internal blood supply found in the marrow at the center of the bone.
Patients with nonunions usually feel pain at the site of the break long after the initial pain of the fracture disappears. This pain may last months, or even years. It may be constant, or it may occur only when the broken arm or leg is used.
To diagnose a nonunion, Dr. Ortega uses imaging studies that provide detailed pictures of the bone and surrounding soft tissues. Depending on which bone is involved, these tests may include x-rays, computed tomography (CT) scans, and magnetic resonance imaging (MRI). Imaging studies let Dr. Ortega see the broken bone and follow the progress of its healing.
A nonunion may be diagnosed if the doctor finds one or more of the following:
• Persistent pain at the fracture site
• A persistent gap with no bone spanning the fracture site
• No progress in bone healing when repeated imaging studies are compared over several months
• Inadequate healing in a time period that is usually enough for normal healing
If the doctor diagnoses a nonunion, he or she may order blood tests to investigate the cause. These tests may show infection or another medical condition that may slow bone healing, such as anemia or diabetes.
Nonsurgical and surgical treatments for nonunions have advantages and disadvantages. More than one alternative may be appropriate. Dr. Ortega will review with you what the risks and benefits are of treating your nonunion and recommend what the best treatment(s) may be in healing your fracture nonunion.
Some nonunions can be treated nonsurgically. The most common nonsurgical treatment is a bone stimulator. A bone stimulator is a small device that delivers ultrasonic or pulsed electromagnetic waves that stimulate healing The patient places the stimulator on the skin over the nonunion from 20 minutes to several hours daily. This treatment must be used every day to be effective.
Surgery is needed when nonsurgical methods fail. You may also need a second surgery if the first surgery failed. Surgical options include bone graft or bone graft substitute, internal fixation, and/or external fixation.
• Bone Graft. During this procedure, bone from another part of the body at the fracture site to “jump start” the healing process. A bone graft provides a new base on which new bone may grow. Bone grafts also provide fresh bone cells and the naturally occurring chemicals the body needs for bone healing.
During the procedure, Dr. Ortega makes an incision and removes (harvests) pieces of bone from different areas on the patient. These are then transplanted to the nonunion site. The rim of the pelvis “iliac crest” and femur are most often used for harvesting bone. Although harvesting the bone may be painful, the amount of bone removed usually does not cause functional, structural, or cosmetic problems.
o Allograft (cadaver bone graft). An allograft (cadaver) bone graft avoids harvesting bone from the patient, and therefore, decreases the pain involved with treating the nonunion. Like a traditional bone graft, it provides scaffolding for the patient’s bone to heal across the area of the nonunion. As time goes on, the patient’s bone replaces the cadaver bone. Although there is a theoretical risk of infection, the cadaver bone graft is processed and sterilized to minimize this risk.
o Bone graft substitutes and/or osteobiologics. As with allografts, bone graft substitutes avoid the bone harvesting procedure and related pain. Although bone graft substitutes do not provide the fresh bone cells needed for normal healing, they do provide a scaffold chemicals needed for growth.
Depending on the type of nonunion, any of the above materials, or a combination of materials, may be used to fix the nonunion.
Bone grafts (or bone graft substitutes) alone provide no stability to the fracture site. Unless the nonunion is inherently stable, you may also need more surgical procedures (internal or external fixation) to improve stability.
• Internal Fixation. Internal fixation stabilizes a nonunion. Dr. Ortega attaches metal plates and screws to the outside of the bone or places an intramedullary nail (rod) in the inside canal of the bone.
If a nonunion occurs after internal fixation surgery, another internal fixation surgery may be needed to increase stability. Dr. Ortega may use a more rigid device, such as a larger rod (nail) or a longer plate. Removing a previously inserted nail and inserting a larger one (exchange nailing) increases stability and stimulates healing within the bone. Internal fixation can be combined with bone grafting to help stability and stimulate healing.
• External fixation. External fixation stabilizes the injured bone, as well. Dr. Ortega attaches a rigid frame to the outside of the injured arm or leg. The frame is attached to the bone with wires or pins. External fixation may be used to increase the stability of the fracture site if instability helped cause the nonunion. External fixation can treat nonunions in a patient who also has bone loss and/or infection.