Malunion and Nonunion

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What Are Malunion and Nonunion?

Malunion and nonunion are both problems that occur when a broken bone doesn’t heal correctly.

What is a malunion?

In a malunion, a bone heals but not in the right position. You may have never had treatment for the broken bone. Or, if you did have treatment, the bone moved before it healed. Malunion symptoms include constant pain long after treatment. If severe enough, the condition can cause a deformity and may require surgery to repair or correct it.

What is nonunion?

A nonunion is the failure of a broken bone to heal.

Where do malunion and nonunion injuries occur?

Malunion or nonunion injuries are most common in the:

  • Bones between the hand and the arm
  • Femoral neck (in your hip joint)
  • Ankle
  • Bone in your foot

Nonunion can also occur in your:

  • Shoulder
  • Elbow
  • Forearm
  • Fingers
  • Knees

Malunion and nonunion can cause pain or even some loss of function.

If a malunion affects a nearby joint, it may lead to arthritis because of unusual wear on the joint.

Malunion and nonunion risk factors and causes

Some people have health problems or habits that cause their bones to fail to heal properly.

Malunion and nonunion risk factors include:

  • Tobacco use
  • Obesity
  • Diabetes or other medical issues

Many things can cause a nonunion, such as:

  • The broken bone does not have enough blood flow.
  • The ends of the bone were not touching when they were stabilized (put in a cast) or corrected by surgery.
  • The broken bone moved before it could heal due to improper stabilization. 

Learn more about malunion and nonunion injuries

From UPMC's HealthBeat Blog:

Malunion and Nonunion Symptoms and Diagnosis

Malunion and nonunion symptoms

Symptoms of a malunion or nonunion can include constant pain long after your fracture was treated.

Both can cause inflammation or infection because of damage to surrounding tissue.

Malunion and nonunion diagnosis

To make a malunion or nonunion diagnosis, your doctor may need to look at the bone or surrounding tissues using:

  • X-rays
  • MRI scans
  • CT scans

If you have a nonunion, your doctor may also run blood or urine tests to look for other issues that may have caused the condition. 

Learn more about diagnostic tests for malunion and nonunion injuries

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Malunion and Nonunion Surgery and Treatment Options

Malunion treatment

Treatment of a malunion often depends on how the injury occurred.

If a bone is misshapen enough to cause a disfigurement, you may need surgery to repair or correct it. Correcting the alignment of the bone is more important if it will cause too much stress on a joint that attaches to that bone.

Nonunion treatment

Treatment of a nonunion depends on what caused it to happen.

Nonunion treatments are limited, but include:

  • Surgery to repair the bone or to remove any infection.
  • Casting or splinting (immobilization).
  • Bone graft (using a piece of your own bone or a cadaver bone).

Medicines for malunion and nonunion

Your doctor might suggest taking anti-inflammation medicine to control any swelling from a malunion or nonunion.

You may also need antibiotics, if you have an infection. 

Learn more about malunion and nonunion treatments

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