What is a stress fracture and what causes them?
Stress fractures in those who are under 20 are typically due to abnormal loading on a normal bone; in other words chronic stress or overuse of a bone (learn about causes and prevention). Bones have a slight give to them, but with repeated stress, micro fractures can occur. Another way to think of this is to imagine a piece of plastic such as a credit card or topper wear lid — you can bend it a few times, but if you bend it too much it starts to get white where it is bent representing a stress reaction and eventually you may crack or fracture.
Who gets stress fractures due to overuse?
Any one can, but in our practice we commonly see it in young athletes where the demand of their activity is greater than what their bones can withstand. This is commonly seen in runners, dancers, gymnasts, and certain ball sports. Stress injuries are seen more in females than males.
Where are the most likely locations for stress injuries/fractures?
The most common location for stress injuries is in the medial tibia where “shin splints” occur. Shin splints, also known as medial tibial stress syndrome are the earliest sign of the stress injury spectrum and often do progress to stress reactions/fractures if not properly treated. In general, stress injuries most often occur in the lower leg (tibia most common, fibula), foot (metatarsals, calcaneus, navicular), femoral neck, and pubic rami. Those who do high impact sports such as sprinters, hurdlers, and jumpers tend to get more in their feet while long distance runners tend to have more tibia/fibula or pelvic stress fractures.
What are the signs of a stress injury?
Pain at the location of the stress injury is the most common symptom of a stress injury. This pain is present during activity, but should subside at rest unless there is high stage injury such as a stress fracture. Point tenderness is also common. Those who have recently begun a sudden increase in intensity or duration of a sport are more prone to develop a stress injury than someone who has not.
How are stress fractures diagnosed?
Typically, a plain radiograph is done first to rule out a frank fracture of the bone. An MRI can provide more detail including any swelling (edema) in or around the bone that represents a stress reaction, however this is not necessary since the diagnosis can be made clinically. Imaging with contrast may provide more detail and allow for a clinician to determine if a smaller fracture is present in select settings. For stress reactions, clinical presentation can clue a provider into the source of pain in most circumstances.
How are stress injuries/fractures treated?
Treatment of stress injuries and fractures depend on the site of injury and the likelihood for complications due to the injury. Stress fractures of the femur, anterior tibia, and some of the foot may require more rigorous treatment including surgical intervention, while common ones of the medial tibia may be managed with conservatively with immobilization with walking boot, rest from sports, and proper rehab once healed. Proper transition to return to sport is critical once the stress injury is healed, as recurrence rates of stress injuries are very high. Typically, return to running or sport is done very gradually increasing duration and intensity by 10-20% per week starting with lower impact activity and softer surfaces.
By Meredith Close and Mo Mortazavi, MD