[Epidemiology of fractures of the proximal femur].

Fractures of the upper end of the femur constitute a major public health problem which, for demographic reasons, will become worse during the next decades. The clinical determination of femoral neck fractures is imperfectly known. Two factors seem to be determinant: bone fragility and fall, but these factors are frequent in the elderly and other factors seem to intervene, notably the modality of the impact and the protection reflexes during the fall. The epidemiology of proximal femur fractures therefore cannot be restricted to the diminution of bone mass. Beside age and female sex, the confirmed risk factors for these fractures are: ethnic origin, absence of replacement hormonal therapy in menopausal women, slight build and absorption of certain psychotropic drugs. To be efficient, preventive measures must rest on a better knowledge of the determinant factors. Epidemiological research should develop rationally and aim at identifying more accurate risk factors, taking into account the mechanisms responsible for proximal femur fractures: fall, lack of cushioning and protection during the fall, and bone fragility.