Navicular Stress Fractures

Navicular Stress Fractures

A navicular stress fracture is a crack in the navicular bone, a boat-shaped bone in the middle of the foot. These fractures often are due to overuse or ongoing force on the bone rather than a sudden injury.

Patients with navicular stress fractures usually have gradual onset of aching pain across the top of the foot. Pain usually improves with rest and support but returns when activity resumes.

The navicular bone helps transfer force from the ankle to the forefoot. The navicular is covered by cartilage and lacks a rich blood supply, especially at its center. This makes it more susceptible to repetitive forces that can cause damage. The bone may break down because of excess force, underlying bone weakness, or a combination of these two factors.

Repetitive forces that could result in a navicular stress fracture include running/jumping sports and similar activities, increased exercise, or even walking after a period of inactivity.

There are steps that can help prevent navicular stress fractures. Select supportive footwear before you start an exercise or training routine and replace your shoes after 300 to 500 miles of use. Supportive shoes typically have a stiff sole with lots of cushioning in the shoe. Start your new training routine slowly, especially after a period of relative inactivity. Do not increase your walking or running distance increments by more than 10 percent per week. Incorporate stretching, particularly of the calf muscles and Achilles tendon, prior to exercise.

A history and physical exam are the most important tools for diagnosing a navicular stress fracture. Physical examination will show tenderness across the top of the foot. Standing X-rays may reveal a fracture line. However, in the early stages of the stress fracture, X-rays often will appear normal. CT, MRI and bone scans may be helpful in confirming the diagnosis if X-rays don't show the fracture.

There are surgical and non-surgical options for the treatment of navicular stress fractures. First, patients must stop the activity that results in the stress fracture pain. Non-surgical treatment includes wearing a cast without weightbearing for 6-8 weeks. Research shows wearing a cast has an 80 to 100 percent success rate.  

Elite athletes often choose surgical treatment to allow them to return to activity more quickly and reduce the risk of developing another stress injury. Surgical treatment involves placement of screws across the fracture. Recovery after surgical treatment usually requires six weeks of limited weightbearing followed by a gradual return to activities.   

The most common complication after treatment of a navicular fracture is a nonunion, or failure of the bone to heal. Continued pain with activity after cast removal is a sign that the bone did not heal. If a nonunion develops, the treatment is surgery. A bone graft in the fracture site can help healing.

Another potential complication is the development of arthritis, resulting from damage to the cartilage that covers the joint connecting the navicular bone to the hindfoot. 

A less common complication of navicular fracture is avascular necrosis (AVN), which results from a loss of blood supply to the navicular bone. AVN causes a collapse of the navicular bone and affects function of the joints in the middle of the foot. It can be difficult to treat.  

How long should I experience pain before making an appointment with my foot and ankle orthopaedic surgeon? Patients should call after 1-2 weeks of persistent foot pain with walking or participating in activities.

Images Powered by Shutterstock