General information on fatigue fracture
A fatigue fracture is a bone fracture (fracture) caused by overstraining the corresponding bone. Very often this type of fracture affects the metatarsus and is characterized by pain. A bone fracture that is not caused by a sudden trauma acting on the bone from the outside, but by overloading the bone, is called a fatigue fracture.
This bone fracture usually develops over a longer period of time by exceeding the individual load limit of the bone, whereby small fractures (microfractures) develop. These can then develop into larger fractures. There are two forms of fatigue fractures, namely the stress fracture and the insufficiency fracture.
A stress fracture is a fatigue fracture of a healthy bone, which occurs more frequently in competitive athletes. In the case of an insufficiency fracture, the bone has already been damaged by osteoporosis or bone tumors, for example. As a result, it is no longer as resistant and can break easily under stress.
In general, the bone is overstressed if it is repeatedly stressed too much, for too long or incorrectly and unilaterally. Therefore, the metatarsus is one of the most common bones affected by fatigue fracture, because it is constantly exposed to high stress when walking. The five metatarsal bones (Ossa metatarsalia), which are located between the toes and the tarsal bones, are summarized as the metatarsus.
The metatarsal is involved in the formation of the arch of the foot and is important for the shock absorption of the body when vertical forces are applied, such as when running. Most commonly, a fatigue fracture of the metatarsus occurs on the second, third or fourth metatarsal bone and is then referred to as marching fracture. This name has its origins in the military sector, as the fracture occurred more frequently in untrained soldiers after long marches. If the fracture affects the fifth metatarsal, it is called Jones fracture.
Causes of a fatigue fracture in the metatarsus
The causes of fatigue fracture of the metatarsus are, on the one hand, overloading of the metatarsal bones due to overstrain. On the other hand, there are a number of factors that reduce bone stability and thus promote fatigue fractures. The metatarsus is stressed during walking.
Since it is the task of the metatarsus to absorb and cushion vertical forces on the body, the metatarsal bones are also subjected to high stress during jumps. This can also lead to fatigue fracture during long jumping exercises. Runners, basketball players and dancers are particularly frequently affected.
Osteoporosis is one of the main factors leading to reduced bone stability. In this case, reduced bone substance is built into the bone and bone resorption is predominant, making the bone porous and susceptible to fractures even at low loads. Osteoporosis often affects older women who, after the menopause, produce less of the female sex hormone estrogen, which is essential for bone metabolism and thus for stable bones.
Furthermore, fatigue fractures of the metatarsus are promoted by foot malpositions such as the hollow foot (Pes excavatus), which can result in incorrect loading, which then leads more quickly to bone wear and consequently to fracture. Another risk of fatigue fracture is drugs that have a negative effect on bone metabolism, leading to brittle bones. The best-known drug that has osteoporosis as a side effect is cortisone.
Malnutrition, eating disorders or unbalanced diets can also lead to reduced bone formation, as there is too little building material available for the bones due to too little nutrient intake. Finally still illnesses of the movement apparatus and the bones exist, like the rheumatoid arthritis, the disease Paget or also the Rachitis caused by Vitamin D deficiency, which weaken the bone structurally and thus bone fractures favoured, like it likewise by bone tumors or also bone metastases with cancer illnesses the case is.
- A sudden extension of the running distance to more than 32 kilometers,
- A new walking technique,
- Increase the running speed,
- Unevenness and a hard surface of the path or
- Abrupt changes in the weight to be carried, for example due to weight gain or a heavy backpack.
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