Avulsion Fracture of the Fifth Metatarsal

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Fractures that occur in the foot are common injuries seen in young athletes, middle-aged weekend warrior's, and elderly patients alike. While the cause of the fracture may differ, these injuries can be seen in just about any age group. One of the most common types of fractures is called an avulsion fracture of the fifth metatarsal

An avulsion fracture of the fifth metatarsal, also called a "Pseudo-Jones fracture," is the most common type of fifth metatarsal fracture.

The fifth metatarsal is the bone that runs from the midfoot to the base of the small toe on the outside of the foot. An avulsion fracture of the fifth metatarsal occurs where a tendon attaches to the bone at this point (the peroneus brevis tendon). When an avulsion fracture occurs, the tendon pulls off a tiny fragment of bone. These fractures are usually not badly out of place. 

Signs of an Avulsion Fracture of the Fifth Metatarsal

Causes of an avulsion fracture in this area include any forced inversion of the foot or ankle - rolling inward. The force causes the tendon to yank a bit of bone off of the fifth metatarsal at the base of the pinkie toe.

This injury can occur in a variety of activities from simply stepping awkwardly off a curb, stepping into a hole, twisting your foot during sports activities or following off a stair. Any activity that causes the foot to forcefully roll inwards can lead to this particular injury.

The common signs of an avulsion fracture of the fifth metatarsal include:

  • Swelling along the outside of the foot
  • Bruising along the outside of the foot extending into the toes
  • Pain with pressure over the outside of the foot
  • Difficulty walking or a limp

Making a Diagnosis

Avulsion fractures can be confused with other types of fractures to the fifth metatarsal bone.

The most common problem is distinguishing this injury from a Jones fracture. The distinction is important because treatment of these injuries is different.

After you injure your foot, you will likely go to your primary care doctor or an urgent care clinic or even an emergency room. The doctor will do a physical examination of the foot and listen to your history of how you sustained the injury. You'll probably be sent for an X-ray to use to diagnose whether it is an avulsion fracture or a Jones fracture. You may also have blood tests to screen your general health and any other contributing factors to the accident. For example, if you were faint or uncoordinated this might indicate a silent medical problem such as diabetes or high blood pressure.

Treatment Options

Treatment of avulsion fractures is usually accomplished with a walking cast or a walking boot. These protect the fracture site, but allow you to walk and place weight on the foot. The walking cast or boot is worn for about four to six weeks. Crutches are not usually needed for this injury, and surgery is seldom necessary. But, needless to say, you won't be doing much dancing for the next month or two as you make a recovery. Resting and icing the area are also in the cards for you during recovery.

Surgery might be needed if the avulsion fracture is displaced. The doctor may recommend an open reduction with internal fixation or a closed reduction with pinning.

A Word From Verywell

A fifth metatarsal avulsion fracture is a common injury that occurs when the foot is twisted awkwardly.  While this injury needs to be distinguished from other types of fifth metatarsal fractures that may require more invasive treatments, a fifth metatarsal avulsion fracture has a very good prognosis and almost always can be managed with very simple treatments.  While there is undoubtedly some discomfort early in the treatment process, symptoms will quickly improve over a matter of weeks, and most people can resume normal daily activities quickly, and sports within a few months.

Sources:

Den Hartog BD. "Fracture of the proximal fifth metatarsal" J Am Acad Orthop Surg. 2009 Jul;17(7):458-64

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