For bone healing to happen, the bone needs adequate stability and blood supply.
Nonunions happen when the bone lacks adequate stability and/or blood flow. Factors
that can increase the risk of nonunion include:
A broken bone also needs adequate nutrition to heal. Protein, calcium, vitamin C,
and vitamin D are absolutely necessary to heal broken bones. A careful diet is the
best way to ensure adequate nutrition; dietary supplements that go beyond the daily
requirements are not effective. The rare exception is the severely malnourished
patient with many injured organs. The physician will discuss dietary guidelines
and make recommendations for dietary supplements as needed.
Nonunions are more likely to happen if the injured bone has a limited blood supply.
They are also more likely if the bone suffers severe trauma, even if it has an adequate
Some broken bones do not heal even when they get the right treatment -- surgical
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, the doctor uses imaging studies. Depending on which bone
is involved, these may include X-rays (radiography), CT (computed tomography), and
MRI (magnetic resonance imaging). Imaging studies let the doctor 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:
Blood tests may also be used to investigate the nonunion's cause. These could show
infection or another medical condition that may slow bone healing, such as anemia
Nonsurgical and surgical treatments for nonunions have advantages and disadvantages.
More than one alternative may be appropriate. Discuss with your doctor the unique
benefits and risks of treating your nonunion. Your doctor will recommend the treatment
option that is right for you.
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.
A surgeon 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 or "iliac crest" is most often used for harvesting bone. Although
harvesting the bone is painful, the amount of bone removed does not cause functional,
structural, or cosmetic problems.
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).
If a nonunion occurs after internal fixation surgery, another internal fixation
surgery may be needed to increase stability. The surgeon 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 blood flow
to a nonunion. An exchange nail is inserted at the end of the bone, which avoids
making a large incision at the site of the nonunion. Internal fixation can be combined
with bone grafting to help stability and stimulate healing.
To reduce the incidence of nonunions, scientists are developing stabilization techniques
that minimize disruption of the blood supply to the bone.
Scientists are also investigating naturally occurring chemicals that the body needs
for bone healing. These chemicals are known as growth factors. When a bone breaks,
they are normally produced in the body in a certain sequence. One of these factors,
BMP 7 (bone morphogenic protein 7), is currently available as a bone graft substitute.
Researchers are concentrating on synthesizing these chemicals and determining the
ideal way to bring them to the injured bone. Someday, physicians may be able to
inject the chemicals directly into the nonunion to promote healing.