Les fractures de fatigue chez le sportif

Stress fractures are very frequent injuries which account for 10% of all consultations in sports medicine, in a majority of cases affecting the lower limbs in young adults. They can be defined as a modification of the bone structure not necessarily associated with cortical infraction which occurs in the absence of injury. They happen as a result of an imbalance between the bone's capacity for adaptation and the overloading of mechanical constraints applied. This imbalance is adjusted by different favourable factors thus explaining the individual threshold to external demands. In theory, any bone might be damaged although more frequently they are to be found at the level of the tibia or the second and third metatarsals. The clinical picture is dominated by a symptomatology of pain which appears progressively strictly mechanical at the development stage. Further medical examination will include an x-ray (late diagnosis which often gives false-negative results) but, more importantly, a scintigraphy (which is very sensitive at an early stage but which is not specific enough). More recently, MRI has been a preferred means of detection. The treatment consists of obligatory segmented rest for a period of between two and six weeks. The intensity and length of treatment vary in function of the location of the injury and the reoccurrence of pain when the offending activity is restarted again. Rest is of utmost importance in order to avoid an evolution towards a true fracture which would result in long-term isolation from sport and social activities.