["Slow" fractures of the metatarsi].

On the basis of clinical observation and reports in the literature, the authors discuss the etiology, pathogenesis, and clinical and radiographic aspects of "slow" fractures, with particular reference to those involving the metatarsal. The different etiologic and pathogenetic theories agree upon one point: the concentration of the stresses as a prelude to areas of osteoclastic resorption which lead to microfractures and thus to "slow" fractures. Many factors are responsible for this concentration, and they may very even according to the site of the lesion. In the foot there are many conditions which can potentially explain the pathogenesis of "slow" metatarsal fractures. Overload of the middle metatarsals is one of the most common causes. The overloaded and fractured metatarsal may then become insufficient and in turn, by the same mechanism, cause fracture of the adjacent metatarsals.