Stress Fracture
What is a stress fracture?
A stress fracture is one type of incomplete fracture in bones. It is caused by "unusual or repeated stress" This is in contrast to other types of fractures, which are usually characterized by a solitary, severe impact. Long distance runners are susceptible to this type of injury. Symptoms include:
- Pain in the affected bone during exercise.
- Tenderness and swelling at a point on the bone.
A stress fracture in athletes occurs mainly in the lower leg and foot (in the calcaneus, navicular and metatarsal bones). A stress fracture of the 2nd or 3rd metatarsal bone is sometimes called a 'march fracture' because soldiers running in boots often get it!
Below we can see a typical stress fracture of the metatarsal in the foot
What are the symptoms of a stress fracture?
Stress fractures usually have only a few symptoms. A stress fracture could present as a generalized area of pain and tenderness associated with weight bearing. Usually when running, a stress fracture in the leg or foot will cause severe pain at the beginning of the run, moderate pain in the middle of the run, and severe pain at the end and after the run.
How is a stress fracture diagnosed?
Physical examination and history are important in diagnosing stress fractures. Because these overuse injuries have a typical course and common physical findings, the history and examination can be critical in the diagnostic evaluation. X-Rays usually do not show a stress fracture, but they may show evidence of bone attempting to heal around the stress fracture. Further studies, including an MRI or bone scan may be necessary if the diagnosis is unclear or if the problem does not resolve with treatment.
Why did I get a stress fracture?
Bones are constantly attempting to remodel and repair themselves, especially during a sport where extraordinary stress is applied to the bone. Over time, if enough stress is placed on the bone that it exhausts the capacity of the bone to remodel, a weakened site a stress fracture on the bone may appear. The fracture does not appear suddenly. It occurs from repeated traumas, none of which is sufficient to cause a sudden break, but which, when added together, overwhelm the osteoblasts that remodel the bone.
Stress fractures commonly occur in sedentary people who suddenly undertake a burst of exercise (whose bones are not used to the task). They may also occur in Olympic-class athletes who do extraordinary quantities of high-impact exercise, in professional and amateur distance runners who run high weekly mileage, or in soldiers who march long distances.
Muscle fatigue can also play a role in the occurrence of stress fractures. For every mile a runner runs, more than 110 tons of force must be absorbed by the legs. Bones are not made to stand that much energy on their own and the muscles act as shock absorbers for the excess force. But, as muscles become tired and stop absorbing most of the shock, the bones experience greater amounts of stress. Finally, when muscles (usually in the lower leg) become so fatigued that they stop absorbing any shock, all forces are transferred to the bones.
What is the treatment for a stress fracture?
The best treatment is almost always resting the injured leg. If there is no evidence that the stress fracture may displace, then avoiding the overuse activity may be sufficient treatment. However, if there is a concern of displacement of the stress fracture, then weight-bearing should be avoided (i.e. use crutches), and a cast may be placed. One rule of thumb (but not an absolute rule) is: if there is pain, don't do it. This means if jogging causes pain where you have a stress fracture, don't jog. If walking causes pain in that location, use crutches.
Other general stress fracture treatment principles include:
- Ice the injured area
- Wear proper equipment, specifically footwear
- Increase activities gradually
- If pain develops and persists, seek medical advice
What a Sports Injury Specialist or Doctor can do:
- X-ray the bone.
- Do a bone scan.
- Apply a plaster cast for 2 - 6 weeks if pain is severe.
When the athlete does start back running they must ensure the muscles in the lower leg are stretched and supple. Many people start back running and complain of pain because they have let their muscles get hard and tight particularly in the lower leg.
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