H

ip fractures are a significant cause of morbidity and mortality in individuals over 70 years of age.1,2 In fact, some 350,000 hospitalizations for hip fractures occur in the United States each year, and 850 hip fractures happen daily.3,4 Furthermore, it is estimated that 500,000 hospitalizations will occur each year for hip fractures by the year 2040 because of the escalating elderly population.5,6
       More than 90 percent of individuals sustaining hip fractures are 70 years of age or older.1,2 Women have a 1/7 chance of fracturing a hip during their life compared to 1/17 for men.3 Thus, women have a two to three times greater risk for hip fractures than men or a lifetime risk of about 20 percent.4 Since the incidence of hip fractures increases with age, approximately one half of all women will develop a hip fracture by age 90.3 It is also interesting to note that women 5'8" or taller have a two times greater risk of having a hip fracture than a woman of shorter stature (5'2" or less).
       The emotional and economic costs of hip fractures are tremendous for society. The economic costs alone for medical care for hip fractures per individual are estimated to be between $33,000 and $37,000 in the United States with a previously reported figure of $2.9 billion annually for Medicare costs.3,4,7 A significant portion of the cost of hip fracture care is due to hospitalization for hip surgery. Total hip replacements performed in the United States during 1999 alone numbered 168,106.2 The economic costs of hip fractures will only increase if successful prevention strategies are not found. Using a five-percent inflation rate, the total annual costs for hip fractures will approximate $240 billion by the year 2040.
       Tragically, the human costs are equally as significant. One quarter of individuals that sustain a hip fracture die within the first year after injury, and as many as one half are discharged to a nursing or extended care facility.1,8 Of these individuals, an overwhelming number remain in nursing homes one year later. Additionally, one half of individuals sustaining a hip fracture will permanently require assistive devices for ambulation. Only 25 percent of individuals that sustain a hip fracture make a full recovery, and statistics show that survivors have a 10 to 15 percent decrease in their life expectancy.
       The major risk factors for hip fractures include:4
- Advanced age (65 years and older)
- Women (especially Caucasian women)
- Family history
- Poor nutrition
- Smoking and alcohol
- Physical impairments
- Mental impairments
- Polypharmacy (taking four or more medications).
       It could also be argued that the above list should include a prior history of falling, as 90 percent of hip fractures are the result of a fall. Many of the above-listed risk factors for hip fractures (advanced age, being a woman, physical and mental impairments, and polypharmacy) are also risk factors for falling.1,9 Table 1 provides a more comprehensive list of known risk factors for falling. Awareness of these factors and early intervention may prevent a serious fall and a subsequent hip fracture.

Hip Fractures: Where, What, and Why
       The proximal femur of young individuals is one of the strongest bones in the body.10 However, with age this bone, particularly the proximal segments, becomes weaker due to decreased bone deposition. Decreased bone formation is linked to reduced circulating estrogen levels as well as inadequate calcium intake. Osteoporotic bone loss in the proximal or upper regions of the femur places elderly individuals, especially women, at risk for hip fracture. Bone loss begins around 35 years of age and eventually culminates in a 30 to 50 percent loss of bone density in women compared to a 20 to 30 percent lifetime loss for men.

Can Hip Fractures be Prevented?
       The answer to this question is yes. Several interventions are recommended to decrease bone loss, increase bone formation, minimize or negate injury to the hip during falls, and prevent falls from occurring altogether. Weight-bearing exercises, such as walking, dancing, and treadmill training among others, are excellent ways to counteract osteoporotic bone loss.10 Exercising for periods of 15 to 30 minutes, three to four times per week is recommended by the National Institute of Aging. The National Institute of Health recommends that both women and men have adequate calcium intake. The recommended level of calcium for menopausal or postmenopausal women not taking estrogen is 1500mg; the level for menopausal or postmenopausal women taking estrogen is 1000mg; and the level for middle-aged men is 1000mg. It is also recommended that individuals at risk for osteoporotic fractures consult with a physician about available preventative drug therapies.
       Another preventative strategy has been added to the above-described traditional armamentarium. This approach involves the use of a device called a hip protector. An example of this device* is shown in Figure 1.

Figure 1. Hip protector brief styles, from left to right: Bob, Betty, and Barbara.

What are Hip Protectors?
       A hip protector is a protective device that is designed to prevent hip fractures during a fall (keep in mind, 90 percent of all hip fractures result from a fall). Hip protectors are made of either plastic shields, foam pads, or silicone pads that are fitted into pockets of specially designed undergarments.4 Hip protectors work by two different mechanisms.12 The first mechanism involves absorption of some of the force associated with a fall onto the hip, thereby decreasing the overall force exerted on the greater trochanter and lessening the chance of hip fracture. The other mechanism involves an energy shunting system that diverts force away from the greater trochanter so that it receives less of the force generated during a fall onto the hip. Diversion of force from the greater trochanter appears to be more effective than absorption in protecting the hipbone, and this is best mediated by the plastic shield design. Some hip protector systems employ one or both of these design principles.

Do Hip Protectors Work?
       In a recent review of the literature by the Cochrane Collaboration,13 an independent reviewing body, it was concluded that hip protectors do appear to reduce hip fracture risk in individuals at high risk for sustaining a hip fracture. However, it is unclear as to whether the hip protectors are efficacious for other populations with lesser risk for hip fracture.

Are There Any Problems Associated with Hip Protector Use?
       The Cochrane Collaboration13 and others12 acknowledge that there are some potential drawbacks of the product. These drawbacks are related predominantly to practicality, cosmesis, and comfort. An acceptance rate of 25 to 99 percent for these devices has been quoted. However, compliance in wearing the hip protector devices does seem to improve with aging individuals who have had a previous fracture or who have a fear of falling. Long-term compliance has not been extensively studied, but there is some data available to suggest that individuals who were initially accepting of the hip protectors may wear the device 60 to 65 percent of the time during the first three months of having the device. This rate appears to improve slightly with specific concerns, such as ambulating during snowy weather.
       Other concerns include the occurrence of hip fractures while hip protectors are being worn.12 However, most of these fractures occur from falls onto the buttocks and not onto the greater trochanter. In these cases, the hip protector offers no protection.

Current Recommendations
       Analysis of current research evidence indicates that hip protectors are effective in preventing hip fractures in the high risk, elderly population. Hip protectors with stiff shells are recommended, as they appear to be the most protective systems. Research studies that employed phantom fallers have demonstrated that energy-shunting systems, such as stiff shells, are more effective in preventing hip fractures than energy-absorbing systems.12 The greatest drawback of hip protectors appears to be individuals' adherence to a wear schedule. Low compliance rates are reported, but compliance may increase with education and future designs. Additionally, with the safety of hormone replacement therapy in question, hip protectors as well as weight-bearing exercise and adequate calcium intake may play an even more important role in hip fracture prevention.

*Impactwear Hip Protective Garments, impactbodywear.com Ltd., Victoria, British Columbia, Canada. impactbodywear.com Ltd. (IBW) has the North American/Mexican rights to the Impactwear Hip Protector that is manufactured in New Zealand. Impactwear Hip Protectors are currently being imported and marketed in Canada by IBW, and IBW is currently applying for licenses to sell its hip protectors in the US. For more information, visit www.impactbodywear.com.