Occurrence and incidence of the second hip fracture.

During a 16-year period, 256 second hip fractures were found in 3898 persons 40 years of age and older who had a previous hip fracture. Ninety-two percent of the second fractures were contralateral, and 68% of these were the same type as the first. Thus, 62% of the femoral neck and 72% of the trochanteric fractures were preceded by a contralateral fracture of the same type. The mean interval between fractures was 3.3 years, and there was no significant difference between genders or among fracture types. The risk of the first fracture was 1.6 per 1000 men per year and 3.6 per 1000 women, and for the second fracture 15 per 1000 men per year and 22 per 1000 women. This increase was highly significant for both genders, especially for men.