STRESS
Bone stress injuries, commonly referred to as stress reactions or stress fractures, are overuse injuries of the bone resulting from repetitive microtrauma with insufficient recovery periods. If you imagine that healthy bone is like a brand new paperclip, you can probably also imagine bending that paperclip back and forth until the metal weakens, then cracks, and finally breaks. There is no one injury that causes the break, but rather it is the accumulation of repetitive stress that causes the injury. And just like that paperclip, if an individual continues to apply stress (physical activity), the injury may progress to a complete fracture (also known as a broken bone).
While bone stress injuries are relatively rare in the general population (less than 1% of injuries), they are fairly common in athletes and military personnel who participate in activities involving repetitive impact loading, such as marching, running, jumping, and dancing. Bone stress injuries represent up to 20% of sports injuries and increasingly are being seen in the pre-adolescent as well as adolescent populations.
The development of a bone stress injury is multifactorial and may include the following:
-too much too soon (think joining a high school cross country team and running 5-6 days per week with no preparation over the summer months)
-changes in usual footwear (for example, abruptly switching from a cushioned shoe to cleats)
-insufficient time for rest and recovery (in other words, no rest days)
-insufficient caloric intake
-Vitamin D insufficiency
-menstrual irregularities (contrary to popular belief, it is not normal for female athletes to miss or skip periods)
-a history of prior bone stress injury
In athletes, bone stress injuries are most commonly seen in the lower extremities, particularly in the front of the lower leg (tibia) and in the feet. These injuries may also be seen in the thigh bone (femur), hip, ribs (particularly in rowers) and forearms (particularly in gymnasts). The pain often develops gradually with no specific injury. The pain tends to get progressively worse with continued activity and, with continued progression of the injury, may persist at rest.
No young pre-adolescent or adolescent athlete should push through pain that gets progressively worse with activities. Evaluation by a medical professional is necessary and will include a thorough patient history, physical examination, and imaging of the body part with x-rays and often MRI.
Once a diagnosis of bone stress injury is made, it is necessary to stop aggravating physical activities. Immobilization of the affected body part and/or offloading with crutches or a knee scooter may be necessary to bring pain levels to zero and allow for optimal bony healing. Laboratory studies, including Vitamin D levels, are recommended to evaluate for any underlying issues that may contribute to delayed healing and/or future bone stress injuries. Nutrition counseling or other education is also recommended to ensure the individual has sufficient caloric intake to support a growing body as well as physical performance.
Complete recovery with return to unlimited physical activity often takes MONTHS. On average, return to sport following a bone stress injury of the shin bone (tibia) takes 16 weeks. This long recovery is often challenging for young athletes and their mental health must be taken into consideration during this time. It is imperative that return to activity follows a gradual progression based on the location of the injury. This gradual progression allows for the bone to adapt to gradually increasing levels of impact stress which will reduce the risk of future injury.
Sports medicine physicians will have a high index of suspicion for bone stress injuries in young athletes. It is never too soon to be evaluated for pain that occurs with activity. The earlier a bone stress injury is identified, the better, for both the athlete’s physical and mental health.
