Age-related factors in the pathogenesis of senile (Type II) femoral neck fractures.

A variety of age-related factors may affect the two ultimate determinants of hip fracture: propensity to trauma and femoral bone quality. The decline in muscle function that occurs with aging increases the incidence and impact of falls. Vitamin D deficiency, common in the elderly, causes impaired mineralization and a hyper-parathyroidism-related increase in bone turnover, reducing bone quality. Skeletal growth factors, essential regulators of bone-cell replication and differentiation, may mediate the maintenance of normal bone mass; the age-related deficiency of these factors may contribute to senile osteoporosis as well. In elderly women, these age-related factors add to estrogen-deficiency-related bone loss, leading to a lifetime risk of hip fracture of approximately 16%. The relative clinical importance of these potential pathogenetic factors remains to be elucidated.