Stress fractures are an overuse injury that occurs from repetitive microtrauma to a bone that then causes the bone to crack and break. They tend to be more common in the lower limbs than the upper limbs because the weight-bearing bones found in the lower limb are at risk to repetitive forces and stress absorbed during activities.  Stress fractures start when the muscles are already tired and fatigued and are unable to absorb more shock causing that force to be absorbed by the bone. Overtime and with repetitive stress the bones and supporting structures do not have enough time to heal the damage thus, tiny cracks develop.

Some people are more prone to stress fractures. Again, muscles help absorb shock, so people with weaker muscles are more prone to stress fractures. As the bone develops the microtrauma there is a complex system of bone healing and remodeling to correct these injuries. People with nutritional deficits including eating disorders are at increased risk of stress fractures. The terrible triad in females: osteoporosis, amenorrhea, and eating disorders, are at high risk of stress fractures. Lastly bone remodel due to stress and gradual increases in stress can help bone actually become stronger. But, large increases in training volume in a short period of time, especially in people who are not training at all, can lead to stress fractures.

The most common sites of stress fracture in the lower limbs are the metatarsals, particularly the fifth metatarsals. This fracture is called the march fracture as this commonly occurs in military recruits. The second and third metatarsal also can develop stress fracture. This is because these bones acquire the greatest impact when walking and running and are thinner than the other metatarsals.  The second metatarsal fracture is most common in dancers and ballerinas. Another common area of injury is the tibia which is the longer of the two bones in the leg and absorbs more stress than the bone above (fibula).

Athletes who play sports which require repetitive running and jumping are vulnerable to stress fractures and it is one of the most common sports injuries as well as in military recruits.

The most common symptom of a stress fracture is pain which develops gradually and there is no other obvious sign of injury to the athlete (some cases may present with tenderness or swelling). Therefore, athletes continue to perform their usual activities such as training and practices without knowing that they already have an injury.

Treatment for Stress Fractures

In most cases, treatment of stress fractures includes rest and avoiding weight bearing activities. This form of treatment allows the bone to heal on its own and usually takes 6-8 weeks. For those who want to remain physically active during this period, training focused on the upper body should be substituted for lower body activities.

In rare cases, the bone may not heal on its own due to the severity of the injury or underlying biological factors. In these cases, a surgical procedure to pin the bone together and insert a bone graft into the fracture may be considered.

The most important aspect to healing properly from a stress fracture is consulting an orthopedic specialist at the first sign of injury so treatment can start immediately and further damage can be avoided.