Malunion & Nonunion Fractures

What are malunion and nonunion fractures?

Malunion and nonunion fractures are poorly healed bone fractures. A malunion fracture is one where the fractured bone parts have grown back together, but in the wrong position. A nonunion fracture is one where the fractured parts have failed to grow back together, even though they’ve had more than enough time to do so. Poorly healed fractures can impact your skeleton’s stability and functionality.

Most bone fractures heal well with good care. If they don’t, it’s because something has inhibited the healing process. Sometimes, it’s a mechanical issue: The fractured parts didn’t hold together well during healing. It can also be a biological issue: Somehow, your body’s resources for healing weren’t up to the task. Healthcare providers must address these factors when treating malunion and nonunion fractures.

Types of nonunion fractures

Your healthcare provider may classify your nonunion fracture as hypertrophic, atrophic or oligotrophic. These classifications are based on the evidence of what types of factors are preventing it from healing.

• Hypertrophic nonunion. This type shows evidence of new bone growth, but the ends of the bone pieces don’t meet. This suggests that your body has adequate biological resources for healing, but the bone pieces didn’t hold together well enough during the recovery period.
• Atrophic nonunion. This type shows no new bone growth and a lack of good blood supply to the bone. This suggests that biological factors are preventing the fracture from healing. Sometimes, there’s evidence of an infection in the bone that’s sapping its blood supply (septic nonunion).
• Oligotrophic nonunion. This type shows some new bone growth, but it’s incomplete. The bone pieces aren’t in the right position. This suggests they didn’t get put back together correctly or they shifted afterward. There may be stability factors and biological factors affecting healing.

What are the signs and symptoms of a malunion fracture?

A malunion fracture might look like:

• Your bone is crooked or bent.
• Your bone is twisted or rotated.
• Your bone is shorter than it used to be.

Using a bone with a malunion fracture may cause:

• Bone pain
• Swelling
• Limping

As your bones are all connected, weakness at the malunion can put extra stress on other parts of your skeleton. This may cause pain in another area of your body when you use the injured bone.

If your misplaced bones stretch or entrap a nerve, you may have nerve-related symptoms, like:

• Numbness and tingling (paresthesia)
• Muscle weakness (atrophy)
• Nerve pain (neuropathy)

What are the signs and symptoms of a nonunion fracture?

Signs and symptoms of a nonhealing fracture may include:

• Deep, chronic pain at the site
• Lasting weakness or limited mobility
• Visible deformity, like a bump or gap

If you have an infection in the bone, you may or may not have symptoms, such as:

• Swelling
• Fever
• Chills

What causes fracture malunion and nonunion?

Many factors can contribute to bone fracture malunion and nonunion, including:

• The nature and severity of the fracture. For example, spiral fractures that break your bone with a twisting motion or comminuted fractures that break your bone into many pieces may be less likely to heal in the right position. Traumatic injuries that impact blood flow to the bone can affect healing.
• How soon and how well it’s been treated. If you don’t seek medical treatment soon enough after a fracture, it may start to heal in a displaced position. Bones can also shift out of place after they’ve been put back in place. This is more likely when treatment comes late or the method is inadequate.
• Whether it’s had an adequate recovery. During recovery, it’s important to keep your fractured bone immobilized and fixed in the correct position for healing. Sometimes, healing takes longer than average. Your provider might remove your cast too soon or you might return to using your bone too soon.
• Your overall health and resources for healing. Slower healing makes malunion and nonunion more likely. Older age, nutritional deficiencies and metabolic conditions, like diabetes and thyroid disease, may delay or prevent bone healing. Tobacco and nicotine use are also known to weaken your bones.

How do healthcare providers diagnose malunion and nonunion fractures?

Diagnosis begins with a complete medical history of your injury and other conditions. Then, your provider will physically examine your bone. They’ll look for visible deformities and gently move it, asking how it feels. Depending on where it is, they might want to watch you walk or measure its length. They’ll follow up with imaging of the bone. Imaging may include X-rays, a CT scan or an MRI.

Your provider will diagnose malunion if they find that the bone has healed in a non-anatomical position. They’ll diagnose delayed union or nonunion if your bone has failed to start or finish healing after a reasonable recovery period. Healing times can vary based on your injury, the bone involved and your overall health status. Your provider may diagnose fracture nonunion after six, nine or 12 months.

Can malunion and nonunion fractures be fixed?

Not all malunion and nonunion fractures need to be fixed. It depends on the bone involved, how much you use it and how much the fracture impacts your day-to-day life. But some nonhealing fractures can limit your mobility and cause pain or other complications. When this is the case, you might need surgery to fix it. Your provider will suggest nonsurgical treatment options first, and surgical options if needed.

Treatment for malunion

Nonsurgical treatments for malunion fractures may include:

• Bracing. A brace can help hold the bone in a better position for using it.
• Orthotics. A shoe insert may help compensate for a difference in one leg.
• Physical therapy. Targeted exercises can strengthen key muscles to take stress off your bone.
• Pain relievers. Over-the-counter medications like NSAIDs can relieve occasional discomfort.

Surgery for a malunion fracture may include:

• Osteotomy. An orthopaedic surgeon may need to cut the bone to adjust its position.
• Limb lengthening surgery. If a limb is too short, your surgeon may attach a lengthening device.

Treatment for nonunion

Nonsurgical treatments for nonunion fractures may include:

• Medical therapy. You might need to treat a systemic disease, an infection or malnutrition.
• Orthoses. A brace, splint or cast can help immobilize the bone while encouraging healing.
• Bone stimulator. These devices stimulate healing with ultrasonic or electromagnetic waves.
• Biologic injections. Stem cells or platelet-rich plasma might stimulate healing and growth.

Surgery for a nonunion fracture may include:

• Debridement. Your orthopaedic surgeon may need to remove dead tissue from the bone.
• Vascular surgery. A vascular surgeon may operate on your blood vessels to restore blood flow.
• Bone grafting. Your orthopaedic surgeon may attach a piece of bone from elsewhere in your body or from a donor bone. The graft provides a fresh starting point for new bone growth.
• Open reduction and internal fixation. Your orthopaedic surgeon may need to readjust the position of your bone pieces and hold them in place with surgical screws and plates or nails.

What is the prognosis after treatment for a nonhealing fracture?

Both nonsurgical and surgical treatments have high success rates for fixing malunion and nonunion fractures. But healing and rehabilitation can take some time. You may need to use a cane or walker to walk while healing, and you’ll spend some time in physical therapy afterward. The treatment may fail if the bone doesn’t stay in position or if your provider can’t control the biological factors involved.