Avulsion Fracture Causes and Treatments

An avulsion fracture is an injury to the bone in a location where a tendon or ligament attaches to the bone. When an avulsion fracture occurs, the tendon or ligament pulls off a piece of the bone. Avulsion fractures can occur anywhere in the body, but they are more common in a few specific locations.

Avulsion fractures are more common in children than in adults. In adults, the ligaments and tendons tend to be injured first, whereas in children the bone may fail before the ligament or tendon is injured.

Children have a particularly weak point in their skeleton, called the growth plate. This is the area of bone that is actively growing. In children, tendons or ligaments near a growth plate can pull hard enough to cause the growth plate to fracture.

A doctor applies cast material to a patient's leg.
Richard Gerstner / Getty Images

Causes 

Often an avulsion fracture occurs when there is a sudden forceful pull on a tendon while the bone is moving in the opposite direction. An example is an injury to the fifth metatarsal, the bone on the outside of the midfoot. The peroneal tendon attaches to the base of this bone.

Often when the foot is twisted, a forceful contraction of the peroneal tendon pulls the foot in one direction, while the twisting force is acting on the foot in the opposite direction. This causes the bone to crack where the tendon attaches to the bone. The good news is that these fractures almost always heal with simple rest and time. 

Diagnosis

An avulsion injury noted on an X-ray film can be confusing, because often these may be related to an old injury. Sometimes a small piece of bone pulled away from the body a long time ago, and only when an X-ray is obtained months or years later is the fragment of bone seen.

It's important not to chase down a treatment for something that doesn't require an intervention. That's why it's critical to have a physician who can both interpret your X-rays and put those results into the context of your injury history and examination findings.

Treatment 

Most often, an avulsion fracture can be treated without surgery. Only when the pulled off fragment of bone is pulled more than several centimeters from its normal position does surgery need to be considered.

In addition, some avulsion fractures affect such small pieces of bone there's no need to repair them. For example, ankle sprains often cause small avulsion fragments. These injuries typically can be treated like an ankle sprain, as the small piece of bone really does not affect the treatment decisions or outcome of the patient.

There are some concerns about treatment when the avulsion fracture involves the growth plate in a child. Because growth plates are important for normal skeletal development, these injuries must be carefully treated. If there is a concern that a growth plate is not correctly positioned, surgery may be performed to align and stabilize the growth plate.

Surgery may not be needed if the avulsion fracture is well aligned, or if the patient is near enough to growth plate closure that this injury will not cause lasting growth problems.

Frequently Asked Questions

  • How long does it take to recover from an avulsion fracture?

    It can take anywhere from six weeks to six months to fully heal and resume full activities. Exactly how long it takes depends on what area of the body you injured and how serious the avulsion fracture was.

  • Does fracturing a growth plate stop your bone from growing?

    Most growth plate injuries heal without disrupting growth as long as they are treated properly. However, sometimes a bony bar develops along the fracture line. This can stunt growth or cause an abnormal curve in the bone. If the bony bar is caught early, a doctor can correct it. 

  • How do you treat a finger avulsion?

    You should see a hand specialist. Your finger will likely be placed in a splint that lets it remain stable while giving you a chance to move it slightly to avoid losing long-term mobility. Surgery is sometimes needed to insert pins into the bone. Physical therapy is usually recommended.

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6 Sources
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