A stress fracture is a type of overuse injury. Athletes in sports that involve a lot of running or jumping are prone to this injury. If it is not detected early, it may lead to a complete fracture of the bone.
The term stress fracture can be a little confusing, as it is not the same as a «normal» fracture where the bone breaks in two. The term is used to describe a weak point or an area in the bone structure that occurs when the bone tissue deteriorates faster than it can repair itself.
To give an idea of how such an injury develops, think of a pencil or wooden stick that is bent to such an extent that it may soon give way, but it is not yet broken. It is basically the same with a stress fracture. The bone is not yet broken but is at risk of that happening.
The lower leg...
is made up of two bones, the tibia and the fibula. The tibia is the larger of the two while the fibula is relatively narrow. Up to 50% of all stress fractures in the body occur in one of these bones, with a higher percentage occurring in the tibia as it bears 90% of the weight placed on the leg.
The most common cause of a stress fracture is a change in training habits. For example, by:
- Drastically increasing the amount of training over a short period of time
- Starting to train again following an injury or illness
- Switching training surfaces (e.g. from grass to asphalt)
There are several factors that, in combination with load, increase the risk of a stress fracture. Women are more prone to stress fractures than men since they have less bone mass and bone density decreases with age. Low muscle strength and muscular endurance result in higher impacts in the joints and an increased load placed on the skeleton. Low levels of calcium and vitamin D affect bone mass density and can thus increase the risk of a stress fracture.
Signs and symptoms
The main symptom is pain in the leg that gets worse during training. In an early stage, the pain will subside with rest, but after a while it can continue during day-to-day activities. Sometimes, but not always, the pain can be localised to a specific point.
It is important to get an early diagnosis to avoid further breakdown of the bone tissue. Sometimes the breakdown can be so great that it eventually fractures completely.
A doctor or physiotherapist will make the diagnosis. In the early stages, it is not common to see signs of a stress fracture using regular X-ray images. As such, MRI is more suitable to confirm the diagnosis.
Treatment of a stress fracture depends on where it is located. Sometimes it is located in a so-called high-risk zone in which case it will be necessary to take all weight off the leg and use crutches for several weeks. Surgery may also be necessary. Other times, the load on the leg can be modified using pain monitoring.
Training that doesn't involve any weight-bearing is allowed. During the non-weight-bearing period it is important to identify possible contributing factors, such as running technique, footwear, training program, and nutrition, as well as to make a plan for how to gradually increase training again. For some athletes it may be useful to have a blood test to measure nutritional levels. Taking dietary supplements has proven to be an effective measure in optimising bone health. A smoother running style with shorter footsteps, a slower pace, and shorter sessions can help decrease symptoms.
The prognosis is good. If the diagnosis is made early and the appropriate weight-bearing limits are applied, most stress fractures in the lower leg will heal and the athlete will be able to return to their former level of activity.