Stress Fractures of the Foot and Ankle: An Overview

Introduction: What is a stress fracture?

A "fracture" is the technical term for a "broken bone," which is a crack in the bone. In fact, the two terms can be used interchangeably. Bones break, or fracture, in two settings: with a significant amount of force, (as in the case of a twisting injury when the ankle bones fracture or a car accident when bones in the foot may break), or when a small or moderate amount of force is applied over and over again to a specific bone. The first type is also called a "traumatic fracture," while the second type is called a "stress fracture." Most commonly, the bone breaks but does not shift position (i.e. does not "displace").

Stress fractures are analogous to bending a paper clip. If you gently bend a paper clip a single time, it will not break. However, if you continue to bend it back and forth, over time it weakens and eventually breaks. This weakening of bone (also called "fatigue") is technically called a "stress reaction." When the bone goes on to actually break, it becomes a stress fracture.

Causes of a stress fracture

Stress fractures themselves happen in two ways.

First, some people with very weak bones - such as those with osteoporosis - can break a bone even with a small amount of activity. This is called an "insufficiency fracture" because it happens in bone that is not "sufficient" to withstand normal forces. Another example of this type of fracture is in younger women that exercise so much that they have irregular or absent menstrual cycles. This leads to weak bone. Second, people with healthy bones can develop a stress fracture if they repeat an activity over and over again. This is particularly the case in athletes who participate in high-impact sports such as track and field, basketball, soccer, tennis, or gymnastics.

The foot and ankle are perhaps the most common places to get a stress fracture because we are constantly on our feet. They occur in people that start a new activity involving impact of the feet on the ground, including heavy walking and running. Stress fractures also happen in people that quickly increase the amount of a certain activity. For example, somebody that normally runs twice a week for 30 minutes that suddenly begins to run seven days a week for one hour is more likely to have a stress fracture.

Shoes that provide poor support, such as high heels - which place a lot of pressure on the toes - and old, stiff shoes can put a person at risk. Finally, people with a foot deformity can develop a stress fracture. For example, in a foot with a bunion, the big toe stops taking on the load it normally should bear, forcing the other toes to be loaded more, which can then cause them to fracture. This is especially true of the second toe.

What bones in the foot are affected by a stress fracture?

Any of the bones of the lower leg and foot can experience a stress fracture. The most common are the metatarsals, which connect the mid-foot to the toes. [See Fig. 1 below.] The heel bone, also called the "calcaneus," can be broken as well. The navicular, a bone near the ankle, can have a stress fracture and takes a long time to heal. Finally, the bones that make up the ankle - particularly the tibia and fibula - are commonly affected.

Figure 1: Anatomical drawing of the foot, showing the metatarsal and navicular bones. 
Illustration by Joseph Yu, BS

How do I know that I have a stress fracture?

Stress fractures cause pain. Therefore, if you have recently changed or increased your activities and have pain in a specific area of the foot or ankle, you may have a stress fracture. The pain usually gets worse as you begin impact activities and gets better with rest. As the fracture worsens, it takes less time after beginning an activity for the pain to start. It tends to hurt in very specific, pinpoint areas, depending on the bone affected, and will hurt if you touch the exact area where the bone is broken.

When should I see my doctor? How are stress fractures diagnosed?

The most important principle is to immediately stop activities that cause pain.

If the pain continues even several days after rest or if the pain goes away but then comes back even after several weeks of rest, you should see an orthopedic surgeon or orthopedic foot and ankle surgeon. These doctors, also called "orthopedists" or "orthopaedists," will ask you questions about the pain, looking for the risk factors noted above.

He or she will also examine you and get x-rays at the area of pain. It is not uncommon for the x-rays to be normal and show no broken bones even when a stress fracture is present. This is because the bone reacts and heals, but the final step is for the new bone to calcify. This calcification is what we see on the x-ray.

In certain cases, the orthopedist may order a bone scan or MRI to give further information and look for a stress fracture earlier than the x-ray might show. It is important to know, however, that these more expensive tests are not routinely needed to diagnosis a stress fracture.

How do you treat a stress fracture?

The most important thing to do when you have a stress fracture is to recognize and stop the activity that caused the problem in the first place. Most stress fractures will heal if you reduce your level of activity and wear protective footwear for four to six weeks. However, the time it takes to heal depends on the bone actually involved. The navicular bone and fifth metatarsal notoriously take longer to heal. Your orthopedist 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 alternate activities.

Immediately following a stress fracture, icing and elevating the affected leg can help decrease swelling and pain. Some data suggests that taking NSAIDs (ibuprofen, naprosyn, etc.) can reduce the ability of bone to heal, so it is best to avoid these medications. Acetaminophen is not an NSAID and is fine to take for pain.

It is important to gradually ease back into activities once the pain is completely gone, typically after six weeks of rest. Activities involving low impact, such as cycling or swimming, are the best. Running and walking on hard surfaces are the worst. In either case, one should ease back into activities and sports over another four to six weeks. Wearing comfortable, supportive shoes without a heel can help, and they should be flexible, not stiff. Runners should increase their mileage very slowly over time. You should not do too much, too soon.

Will I need surgery?

Most stress fractures heal by resting and gradually easing back into activities. On rare occasions, your orthopedist may recommend surgery, usually only after trying to heal the bone over a long period of time with the methods described above.

Preventing stress fractures

Given what you have learned about stress fractures, it is important to find ways to prevent them from occurring. The following principles can help you lead a healthy lifestyle and avoid problems with stress fractures.

• Eat calcium-rich foods and ensure you get enough daily Vitamin D to help maintain bone density.
• Wear good shoes. Do not wear old or stiff shoes, but instead try comfortable, well-padded, and supportive shoes. It is usually a good idea to wear shoes made specifically for the sport you would like to do. Avoid high heels whenever possible.
• Do not smoke. This can lead to problems with healing. It is actually the nicotine that creates the problem, so other gum and products containing nicotine will still prevent the bone from healing.
• Cross train. This means that you alternate your activities. For example, you can alternate jogging with swimming or cycling.
• Slowly ease into previous or new sports activities. Gradually increase the time, speed, and distance. Many experts suggest a ten percent increase per week.