Stress Fractures of the Foot and Ankle

Stress fractures are a type of overuse injury. These tiny cracks in your bones develop when your muscles become overtired (fatigued) and can no longer absorb the shock of repeated impacts. When this happens, the muscles transfer the stress to the bones, creating a small crack or fracture. Stress fractures also can occur with normal usage if osteoporosis or some other disease weakens your bones and leaves them vulnerable. These fractures are often called "insufficiency fractures" because there isn't enough bone to withstand the normal stress of daily use. Most stress fractures occur in the weight bearing bones of the foot and lower leg. The most commonly affected site is the second or third of the long bones (metatarsals) between the toes and the midfoot. Stress fractures also can occur in the heel, the outer bone of the lower leg (fibula) and the navicular, a bone on the top of the midfoot.

Risk factors for the development of stress fractures include athletic activities such as track and field, basketball, gymnastics, ballet or tennis, injuries in adolescents whose bones have not yet fully hardened, women, particularly female athletes, who have abnormal or absent menstrual cycles that can result in decreasing bone mass, and in military recruits who suddenly must shift from a sedentary civilian life to a more active training regime.

Doing too much too soon is a common cause of stress fractures. Runners who have an inappropriate training regimen are at increased risk for development of such injuries. The use of improper sports equipment, such as shoes that are too worn or stiff, also can contribute to stress fractures. A change of surface, such as going from a grass tennis court to one of clay or from an indoor to an outdoor running track, can increase the risk of stress fractures. Errors in technique are another cause of stress fractures. Some conditions, such as flatfoot or bunions, can change the mechanics of your foot and make stress fractures more likely to develop.

Some of the signs and symptoms associated with stress fractures include pain that develops gradually, increases with weight-bearing activity, and diminishes with rest, swelling on the top of the foot or the outside ankle, and tenderness to touch at the site of the fracture.

If you suspect a stress fracture in your foot or ankle, stop the activity and rest the foot. Ignoring the pain can have serious consequences, and the bone may break completely. Apply an ice pack and elevate the foot above the level of your heart. Stress fractures are difficult to see on X-rays until they've actually started to heal. The diagnosis is usually therefore clinical but in some cases, further testing such as a bone scan may be necessary.

Treatment will depend on the location of the stress fracture. Most stress fractures will heal if you reduce your level of activity and wear protective footwear for two to six weeks. Your orthopaedist may recommend that you wear a stiff-soled shoe, a wooden-soled sandal, or a removable short leg fracture brace shoe. Athletes should switch to a sport that puts less stress on the foot and leg. Swimming and bicycle riding are good alternative activities.

Stress fractures in the fifth metatarsal bone (on the outer side of the foot) or in the navicular or talus bones take longer to heal, perhaps as long as six to eight weeks. Casting and the use of crutches may be necessary until the bone heals. In some cases, surgery may be necessary to assure proper bone healing.

Because stress fractures that don't heal properly can develop into complete breaks of the bone and can become a chronic problem, it's better to prevent them in the first place. Here are some things that you can do: maintain a healthy diet and eat calcium-rich foods to help build bone strength, use the proper equipment for your sport such as new running shoes, alternate exercise activities, slowly increase any new sports activity, and if pain or swelling returns, stop the activity and rest. If the pain persists, seek medical attention.

Modified from the AAOS