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: