Increase in the incidence of cervical and trochanteric fractures of the proximal femur in Niigata Prefecture, Japan.

This study aimed to determine the incidence of cervical and trochanteric fractures of the proximal femur in 1994 in Niigata Prefecture, Japan, and to compare this incidence with those previously reported in Niigata in 1985, 1987, and 1989. We visited all hospitals within Niigata Prefecture having an orthopedic department and reviewed the medical records and radiographs of all patients who sustained such fractures in 1994. The population of Niigata Prefecture was determined in 1994 to be 2,483,879 (1,205,151 males and 1,278,728 females). The population over 65 years of age was 428,795 (172,788 males and 256,007 females), representing 17.3% of the total population. In 1994, there were 1,468 cervical or trochanteric fractures in 378 males and 1,090 females, with a male-to-female ratio of 1:2.9. The incidence of these fractures in persons over 65 years of age was 304 fractures per 100,000 population per year. Of 528 cervical and 940 trochanteric fractures, the latter accounted for 64% of the total number. The age-specific incidence of the fractures in Niigata exhibited an exponential increase with age, similar to those reported in Sweden and the United States. However, the incidence was lower than in those countries. When comparing the number of cervical and trochanteric fractures in 1994 with the numbers reported in 1985, 1987, and 1989, it is evident that the overall number and incidence of these fractures has been increasing over this period. Even if the difference of the age-specific population among these years is adjusted, the fractures have been increasing.