Navicular stress fracture
The navicular is one of the bones in the midfoot. A stress fracture is an overuse injury that results when too much stress is placed on a bone. Repetitive stress will initially cause swelling in the bone. If the stress continues, it eventually causes the bone's cortex (outside layer) to weaken and crack. A navicular stress fracture usually gets better if properly treated, but if ignored, it may lead to chronic foot pain.
How it occurs
The navicular bone is especially prone to stress fractures for two reasons:
- The bone is exposed to a large amount of mechanical pressure during weight-bearing activities, especially running and jumping
- It has a relatively poor blood supply compared to other bones, so has limited ability to heal after being stressed.
Navicular stress fractures are most commonly seen in athletes who participate in running and jumping sports (soccer, cross-country, track and field & gymnastics). While navicular stress fractures are primarily due to overuse, sometimes there are additional contributing factors such as improper shoe wear, improper running or landing technique, or a change in running surface. Finally, some foot types are more prone to navicular fractures than others.
Signs and symptoms
Vague, aching pain along the inner side of the foot near the arch is typical. The pain may come on slowly over time and get worse during and following physical activity. Sprinting, jumping and pushing off are movements that aggravate the pain. It often occurs after a change in intensity or duration of physical activity or a change in shoe wear or running technique.
Diagnosis
Your doctor will examine your child's foot and ankle. The navicular bone may be tender to touch and there may be pain with hopping and standing on the toes. Sometimes x-rays show the fracture but not always. If suspicion is high, your doctor may consider an MRI, a CT scan or a bone scan.
Treatment
Treatment should begin with a cast and crutches. Your child should not bear weight on her foot for at least 6 weeks. Then her doctor will re-examine the foot, and if the pain is better, she may start bearing weight. If the pain is still present, she may be allowed to bear weight in a walking cast or boot until the pain resolves. Once she is bearing weight comfortably, her doctor will prescribe physical therapy so that she can regain strength. Most patients are able to return to sports in 3 months, but some may require up to 8 months to return to full activity.
Returning to activity and sports
The goal is to return your child to her sport as quickly and safely as possible. If your child returns to play too early, or plays with pain, she is at risk for chronic foot injury.
After a period of casting and once pain has completely resolved, rehabilitation proceeds as follows:
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Weeks 1 to 2
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Normal activities of daily living. Swimming and water running are permitted.
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Weeks 3 to 4
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If there is no increase in pain or tenderness over the navicular bone during weeks 1 to 2, jogging on grass for five minutes on alternate days is permitted. After one week, increase to 10 minutes on alternate days.
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Weeks 5 to 6
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If there is no increase in pain or tenderness over the navicular bone during weeks 3 to 4, running to 50 percent of maximum speed with walk recovery on alternate days is permitted. This speed can be increased to 75 percent over another two weeks.
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After 6 weeks
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If there is no increase in pain or tenderness over the navicular bone during weeks 5 to 6, your child can gradually return to full training activity as tolerated.
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