What Is a Stress Fracture?A stress fracture is generally the result of overuse or repeated trauma to a bone. Also known as "fatigue fractures," a stress fracture occurs when muscles become fatigued or overloaded and can no longer absorb the stress and shock of repeated impact. When fatigued, the muscles transfer that stress to the nearby bone and the result is a small crack or fracture in the bone. The most common stress fractures include:
Stress fractures in the bones of the foot are usually caused by overtraining or overuse. They can also be caused by repeated pounding or impact on a hard surface, such as running or jumping on concrete. Increasing the time, type or intensity of exercise too rapidly is another common cause of stress fractures to the feet and lower leg. Running in old, worn out shoes can also lead to stress fractures.
Women seem to be at greater risk of foot stress fractures than men. This may be related to a condition called "the female athlete triad," which is a combination of poor nutrition, eating disorders, and amenorrhea (infrequent menstrual cycle), that predispose women to early osteoporosis (thinning of the bones). The result of this type of decreased bone density is an increase in the risk of stress fractures.
High-impact sports such as running, gymnastics, and volleyball can increase the risk of stress fractures. In all of these sports, the repetitive stress of the foot strike on a hard surface causes trauma and muscle fatigue. Without the right shoes, good muscle strength or adequate rest between workouts, an athlete can develop a stress fracture.
Risk Factors for Recurrent Stress FracturesResearchers have identified several factors that may predispose athletes to multiple stress fractures of the lower extremities. These factors include the following:
- A high longitudinal arch of the foot.
- Leg-length inequality.
- Excessive forefoot varus (inward turning).
- Amenorrhea or menstrual irregularities in female athletes.
- High weekly training mileage in runners.
Stress Fracture DiagnosisStress fractures may be difficult to diagnose because the symptoms are often vague and slow to appear. A generalized ache or tenderness over the bone in the area of the stress fracture may initially be diagnosed as muscle injury or muscle strain. Stress fractures of the tibia lower leg) are often misdiagnosed as shin splints in the early stages.
In order to diagnose a stress fracture, a physician will perform a complete history and physical examination. It's important for athletes to explain their training history, including the type of exercise, as well as how much and how often they train.
X-rays may not reveal a stress fracture, but are helpful in showing signs of bone remodeling near the stress fracture. An MRI or bone scan is better able to show a stress fracture, but is usually only ordered if treatment fails to reduce symptoms of a stress fracture.
Stress Fracture TreatmentThe best treatment for a stress fracture is rest. Taking a break from a high-impact exercise routine, such as running, and doing some low impact exercise, such as cycling or swimming, for several weeks can help the fractured bone heal. If an athlete pushes through pain and trains with a stress fracture, the fracture can enlarge or become a chronic injury that may never heal properly.
After rest, the typical stress fracture treatment recommendations include:
Preventing Stress FracturesThe following advice may protect you from developing stress fractures in the first place:
- Follow the 10 Percent Rule. Progress slowly in any sport and gradually increase time, and intensity, running mileage or effort.
- Eat well, and include calcium-rich foods in your diet, especially if you are a female athlete.
- Wear proper foot wear and replace shoes when needed.
- If pain or swelling begins, immediately stop the activity and rest for a few days.
- If continued pain persists, see your physician.
Any foot pain that continues for more than one week should be seen by a doctor for a thorough evaluation and diagnosis.
Raija Korpelainen, MSc, et al. Risk Factors for Recurrent Stress Fractures in Athletes. The American Journal of Sports Medicine. May 2001 29:304-310.
Stress Fracture - Patient Information. American Academy of Orthopaedic Surgeons. Accessed: July 8, 2009. orthoinfo.aaos.org/topic.cfm?topic=A00112