Hip Fractures

Osteoporosis is sometimes termed the "silent epidemic" because early osteoporosis is asymptomatic, and significant bone loss may become evident only after a hip or vertebral fracture has occurred. Fractures, especially of the spine, hip, and wrist, are the clinical complications of osteoporosis.  

Fractures, the clinical manifestations of osteoporosis, depend on a variety of factors including the propensity to fall, visual acuity, response to falling, and bone strength. However, bone mass is the most important determinant of bone strength and accounts for up to 80% of its variance. Many prospective studies of older subjects have shown that levels of bone density at the spine or hip that are one standard deviation below the population mean increases the risk by a factor of two to three.

Fracture site is age related. For individuals in their 50s, wrist fractures are most common. Individuals in their 60s are more likely to sustain fractures of the vertebrae of the spine, and by the time an individual reaches the 70s, the hip becomes the most common site of osteoporotic fracture. The rates of all three types of fracture increase with age, but the increased risk with aging is most pronounced for hip fractures.

Hip fractures are the most serious osteoporotic fractures and most of them follow a fall from the standing position, although they may also occur spontaneously. Within a year of a hip fracture the mortality rate is as high as 20% with reduced functional capacity in 50% of surviving patients.

There is pronounced geographical variation in the incidence of hip fracture, with rates being highest in Caucasians living in North Europe, followed by rates in Caucasian living in North America. the female to male ratio for hip fracture was 3:1 in Caucasians, but 1:1 in Chinese. The incidence of hip fracture also varies between subjects of the same origins but living in different countries. In Europe, the incidences of hip fracture vary more than 7 folds from one country to another Recent research suggested that the incidence of hip fracture has experienced either a leveling off or a slightly downturn in North America and Europe.

Assuming no increase in hip fracture incidence, the number of hip fracture patients will continue to rise in all continents, as a result of population ageing. The incidence rates for hip fracture increase exponentially with ageing in both sexes. The average age at which osteoporotic hip fractures occur is about 80 years in developed countries but is less in countries with lower life expectancies.

The mortality attributable to osteoporosis results largely from hip fractures. Hip fracture causes a 12% to 20% reduction in expected survival. Hospital-based studies showed that death rate was higher in men, older patients and in non-white populations. Osteoporotic fractures cause varying degrees of morbidity. Hip fracture causes much disability. Many hip fracture patients become permanently disabled. Up to a third of hip fracture patients become totally dependent, necessitating institutionalization.