Can Hip Protector Use Cost‐effectively Prevent Fractures in Community‐dwelling Geriatric Patients?

To the Editor: I enjoyed reading the scholarly work of Honkanen et al., “Can Hip Protector Use Cost-Effectively Prevent Fractures in Community-Dwelling Geriatric Patients?”1 I think it is fair to say that the data supporting a general policy of providing hip protectors are conflicting. The Cochrane meta-analysis cited in the paper (reference 23) concludes that “Pooling of data from 3 individually randomized trials involving 5,131 community-dwelling participants showed no reduction in hip fracture incidence from the provision of hip protectors.” In addition, pooling of data from 11 trials conducted in nursing or residential care showed a marginally statistically significant reduction of hip fracture (relative risk =0.77). This analysis showed significant statistical heterogeneity.2 Another recent meta-analysis included a post hoc subgroup analysis of two trials consisting of nursing home residents (N=1,014). Hip protector allocation produced a significant risk difference of −4.4%, with a relative risk of 0.50. The authors concluded that there is little evidence to support the use of hip protectors outside the nursing home (higher risk, caregiver-enforced compliance), although the benefit of hip protectors in nursing home residents requires confirmation.3 Finally, “A cluster randomized controlled trial to evaluate a policy of making hip protectors available to residents of nursing homes” that involved 40 intervention homes and 87 control homes found that making hip protectors available to residents of nursing and residential homes did not reduce the rate of hip fracture.4 It has been difficult to establish the effectiveness of hip protectors based on intention-to-treat analysis because of nonadherence, so efficacy estimates have also been based on comparing number of fractures during falls wearing hip protectors with number of fractures during falls without hip protectors. Donning a hip protector is a functional stress test. Those randomized to the use of hip protectors who were actually wearing the protectors during a fall may have higher functional ability with fewer incontinence episodes and less resistance to care to allow staff to apply the hip protectors or the greater strength and flexibility required to don the hip protectors independently. I assume that patients would be more likely to wear the hip protectors during daylight hours when attentiveness and lighting are optimal. These factors could also account for the calculated efficacy used by Honkanen et al. to calculate the cost effectiveness of hip protectors Many in vitro mechanical experiments report that the impact of striking the ground during a fall to the side can produce a hip fracture, but some hip fractures may occur before impact with the ground as a patient falls while the torso pivots around a foot fixed to the ground. The torsional shearing forces generated during such a fall are considerable and are capable of shearing the bones and ligaments of young, athletic individuals (ankle, anterior cruciate ligament) and surely capable of shearing an osteoporotic hip. I believe this mechanism of injury deserves consideration. This mechanism would also be consistent with the observation that falls to the side are associated with hip fracture and the observation that individuals with longer femoral necks are more prone to hip fracture.5 I suspect that direct impact produces many osteoporotic hip fractures, but internal shearing may also account for some cases. Sometimes hip protector advocators fail to fully acknowledge that the data regarding efficacy of providing hip protectors are conflicting. Financial Disclosure: Dr. Paul Drinka is a member of the Speakers Bureau and a consultant for Glaxo-Smith-Kline and Roche Laboratories. Author Contributions: Dr. Paul Drinka was responsible for the entire letter. Sponsor's Role: This letter received no grant support and had no sponsor.