Impact of Trauma-Related Hip Fractures on the Older Adult
This article is the sixth and final article in a series on trauma care and the older adult. The series discusses the growing problem of trauma in the elderly, including its causes and possible ways to prevent it, care in the acute stages, and manifestations and treatment strategies when trauma involves the torso, spine, brain, and hip. Authors include skilled experts in the trauma field representing various specialties at the R Adams Cowley Shock Trauma Center at the University of Maryland Medical Center and the University of Maryland School of Medicine.
Introduction
Traumatic injuries involving falls are a major concern for a rapidly aging population.1 Hip fracture is the second leading cause of hospitalization for older persons, and each year there are approximately 350,000 hip fractures in the United States, occurring predominantly in older adults (≥ 65 yr) with underlying osteoporosis.2,3 Hip fractures frequently result from minor trauma or a fall, although they may also occur as the bone becomes so deteriorated or fragile that it can no longer support the weight of the individual. Although some data suggest that the age-adjusted incidence of hip fracture has decreased in the last decade,4,5 the dramatic growth of the older population will greatly increase the number of hip fractures that occur annually; by the year 2040, it is expected that there will be 500,000 hip fractures annually.6 The incidence of hip fractures increases exponentially with age (half of all hip fractures occur in persons over age 80 yr), and approximately 75% of hip fractures occur in women.3 These injuries have significant consequences not only to the person affected, but also to his/her family and to society in general. This article will address: (1) the classification of hip fractures; (2) what is known about the sequelae of hip fractures; and (3) aspects of prevention.
Classification of Hip Fractures
The hip is a ball-and-socket synovial joint that is enclosed by a thick articular capsule. It is able to support one’s entire weight and move freely to allow mobility and motion in an almost 360-degree manner. Ligamental structures and muscles help provide support to the hip joint. The round head of the femur articulates with the cuplike acetabulum. This results in significant shearing forces as the hip joint moves to allow mobility. A fracture results when exerted forces exceed the strength of the bone, and they may occur at any aspect of the proximal femur from its head to the first 4-5 cm of the subtrochanteric area. Fractures involving the greater trochanter are rarely the result of trauma and most frequently result from avulsion-type injuries, as may occur in gymnasts and dancers. Intertrochanteric fractures occur when the bone between the greater and lesser trochanters breaks with or without displacement. Subtrochanteric fractures most commonly occur in persons suffering from trauma.
Hip fractures are classified based on their relation to the hip capsule (eg, intracapsular and extracapsular), specific location (eg, head, neck, trochanteric, intertrochanteric, subtrochanteric), and degree of displacement. Fractures involving the femoral head and neck are classified as being intracapsular; those of the trochanteric, intertrochanteric, and subtrochanteric areas are classified as being extracapsular. Intracapsular hip fractures are more prone to complications, such as nonunion and avascular necrosis due to the thick capsule that surrounds these fractures and separates them from soft tissues and blood supply. This results in an impaired ability to form a callous, and thus to heal appropriately. Fractures may have a single defect or multiple defects (comminuted fracture) associated with it. A discussion of the specific treatment for the varying types of hip fracture is beyond the scope of this article.
Hip Fracture Outcomes
Hip fractures challenge the prospects of a continued quality of life for older adults. Negative outcomes associated with hip fractures include, but are not limited to: mortality; limitations in mobility; decline in bone mineral density (BMD), lean body mass, and strength; and quality-of-life issues such as persistent pain and depression.
Numerous epidemiological studies have demonstrated an increased mortality risk following hip fracture in older adults. An estimated 18-33% of older hip fracture patients die within the first post-fracture year (13.5% die in the first 6 mo).7,8 A recent meta-analysis indicated that, as compared to age- and sex-matched individuals, those who fracture a hip have a five to eight times increased risk of mortality during the first three months after hip fracture.9 This excess mortality persists for ten years following the fracture and is substantially higher in men. The exact causes of this increased mortality are still not completely understood, but age, gender, psychological well-being, pre-fracture mobility, place of residence, social support, and comorbidities appear to influence post-fracture decline and mortality.8,10
Those who survive the initial period following a hip fracture are at increased risk of mobility and functional limitations. Epidemiologic studies comparing hip fracture cohorts to noninjured comparison groups have demonstrated a significant decline following a hip fracture in both upper-extremity and lower-extremity functioning for as long as six years following the fracture.11 Only 50-60% of hip fracture patients will recover their pre-fracture walking capabilities in the first year post-fracture.12 Many hip fracture patients who were independent in their activities of daily living (ADL) prior to the fracture will have new dependencies in some of these tasks. The extent of dependency and recovery in these areas is variable across tasks. For example, while 20% of hip fracture patients will require assistance to put on their pants (dependence in dressing) at 12 months post-fracture, nearly 90% will require assistance to climb five stairs.13
Hip fractures also affect other quality-of-life domains during the hospitalization and subsequent recovery. For instance, hip fracture patients express a high degree of depressive symptoms post-fracture. Magaziner et al13 found that 45.7% of patients tested during their hip fracture hospitalization had clinically significant levels of depressive symptoms (Centers for Epidemiologic Studies Depression Scale scores of 17 or higher), and 44% of these patients still experienced the symptoms two months after the fracture. Depressive symptoms have been shown to affect post-fracture functional recovery as well.10 Persistent pain also has been noted as a common outcome from a hip fracture. Assessments of hip fracture patients conducted at an average of 103 days after hip replacement surgery revealed that 42% of these hip fracture patients reported moderate-to-severe hip pain within the past month, and 27% of the sample reported severe hip pain at least once a week.14 Persistent pain was associated with greater difficulty in performing ADL, lower quality of life, and more depressive symptoms.
Recurrent falls and fractures are common among those who suffer a first fracture. Risk factors that have been associated with having a second hip fracture include advanced age, cognitive impairment, reduced BMD, decreased visual depth perception, reduced mobility, dizziness, and poor or fair self-perceived health status. Cohort studies have demonstrated an increased risk of any clinical fracture in older individuals who have had a previous fracture, and the most elevated relative risk was shown for those who suffered an initial hip fracture from a low-trauma impact.15 The cumulative incidence of a hip fracture in those who have already suffered one fracture is estimated to be 10% for women and 5% for men.4 Additionally, secondary hip fractures tend to be of similar type to the previous fracture and share the same risk factors.16 The increased risk may be due to the decrease in bone, lean body mass, and strength that occurs after a hip fracture.17 The current evidence suggests, however, that neither functional recovery nor hospital length of stay is affected by recurrent hip fracture as compared to the initial fracture.18
Many of the generalizations regarding outcomes following a hip fracture result from studies conducted primarily in older white women due to this demographic group having the highest incidence of hip fractures. Thus, there has been an underrepresentation of both men and minorities in previous hip fracture studies.19 The existing evidence, however, suggests that post-fracture mortality rates are greater for men than for women, and that both mortality and mobility limitations are higher in nonwhites as compared to whites.19 These findings would suggest that caution be used when designing care plans for nonwhite and male hip fracture patients to account for possible biases in the reported literature.
Due to the high likelihood of multiple medical conditions coexisting at the time of the fracture and decreased physiologic reserve in older adults, there are many complications that occur during the hospitalization period.1 Delaying surgery for two or more days increases the mortality rate by 17%20,21 though these data may be confounded by preexisting medical conditions that lead to a decision to delay surgery while attempts are made to medically stabilize the patient. Other complications associated with delaying surgery may include deep venous thrombosis, pulmonary embolism, pneumonia, skin breakdown, joint infection, blood loss, depression, and muscle atrophy.21 As one might expect, general anesthesia used during hip fracture repair has been associated with higher morbidity than the use of epidural/spinal anesthesia.22
Intensive injury management, similar to that seen in a trauma unit setting, may be a better approach to managing complicated geriatric hip fracture patients, even in the absence of other injuries. It was recently demonstrated that a clinical practice comanaged by geriatricians and orthopedists can improve the outcomes of older adults who fracture a hip.6 The guidelines followed during this study were protocol-driven and required that hip fractures were rapidly repaired with surgery, that the patients’ care was comanaged by multiple disciplines, and that discharge planning began at the time of admission.
Hip Fracture Prevention
While preventive measures and pharmacologic intervention have the ability to slow, if not prevent, the decline in BMD associated with hip fractures,23 more older persons than ever before are participating in high-risk activities that predispose them to traumatic injury.1Any bone, even those with normal BMD, will fracture if sufficient stress is applied, and thus the type of traumatic injury clearly plays a role in determining the extent of injury. Fortunately, many hip fractures can be prevented with attention to improving BMD throughout life and reducing factors that predispose to falls.24 Few single preventive measures have been shown to decrease the risk of hip fracture,24 partially due to the myriad risk factors associated with falls and fall-related hip fractures. While treating osteoporosis has been shown to reduce the incidence of hip and vertebral body fractures, multifaceted interventions have been shown to be the most effective method for preventing falls, and thus hip fractures.25
A great opportunity exists for the medical community to intervene before fractures have occurred. The screening for and treatment of osteoporosis is a necessary but underused strategy, especially in older men who are rarely diagnosed or treated for osteoporosis, even after an osteoporotic fracture.26 Men with reduced levels of androgen or those who have been on medications that interfere with normal bone metabolism may also present with significant osteoporosis, thus increasing their risk of a fracture. Osteomalacia due to a deficiency in vitamin D also may predispose to fractures and must be considered in any person with osteopenia. Assessments that include measurements of BMD along with fracture risk calculations, such as the Fracture Risk Index27 or the algorithm created by the American Geriatrics Society,28 are more effective than BMD assessment alone.
Nutritional interventions, including adequate intake of calcium and vitamin D (as prescribed by the National Osteoporosis Foundation),29 have proven effective in preventing hip fractures,30 but these vitamins and nutrients remain deficient in the majority of older adults at risk for hip fractures.31 A daily intake of 1500 mg of elemental calcium is recommended for the majority of persons with osteoporosis, and 25 OH vitamin D levels (the storage form of vitamin D) should be maintained above 30 ng/mL. This usually requires a daily intake of at least 800-1000 IU of vitamin D, with many persons requiring higher amounts.
Behavioral/exercise interventions that include physical activity (ie, interventions that encourage walking, weight-bearing activity, resistance training) have been associated with a reduction in the incidence of falls and fracture.32,33 These findings may be attributable to increases in strength, muscle mass, dynamic balance, and BMD that are observed in older adults undergoing exercise interventions that include resistance training.33-35 While still debated, there is evidence that tai chi is an especially cost-effective intervention for reducing fall risk in older adults.30,36
Other effective prevention strategies to decrease falls include decreasing the number of medications, especially psychoactive medications, antihistamines, sleeping pills, sedatives, and those causing orthostatic blood pressure changes. Reducing the use of psychoactive medications is difficult, and studies have shown that older adults tend to resume their use after being told to discontinue them.24,28,30 Additionally, modifying the older person’s home environment to avoid fall hazards has been shown to be effective, especially in those who have previously fallen or who have risk factors for falls. Correcting vision and the proper use of adaptive equipment such as walkers and canes is also advised.24
Pharmacologic interventions have demonstrated effectiveness for preventing hip fractures. For instance, clinical trials have illustrated the effectiveness of bisphosphonates to improve BMD and reduce hip fractures among compliant patients; this drug class is recommended as first-line treatment for individuals diagnosed with osteoporosis.37 It is important to stress the need to continue to take adequate amounts of calcium, as the use of a bisphosphonate without sufficient calcium will result in negative effects on BMD. Hormone replacement therapies are now limited in treating osteoporotic women because of the balance between their effectiveness and potential harm. Other pharmacologic options are available to prevent hip fractures as well; these include calcitonin, raloxifene, and parathyroid hormone.3 A discussion of the efficacy of these drugs is beyond the scope of this article.
Secondary Prevention
As previously mentioned, a hip fracture is one of the strongest risk factors for a subsequent hip fracture, yet efforts to reduce the risk of recurrent falls and injuries have been limited. Few patients (< 30% of women and 10% of men) with previous hip fractures are treated to prevent subsequent fractures, and less than 40% of patients with low-trauma fractures are diagnosed with osteoporosis.15,38 Therefore, a great need and opportunity exists for secondary prevention efforts.
The interventions for both primary and secondary prevention of hip fracture are similar. First, hip fracture patients’ fall risk should be ascertained and managed to prevent recurrent falls and fractures. Independent of BMD, risk of falling is increased with neuromuscular disorders, low vitamin D levels, advanced age, frailty, and visual deficits. Interventions that focus on geriatric consultation, continuous rehabilitation, and discharge planning have been demonstrated to improve clinical outcomes (including walking ability) and self-care abilities, and to decrease depressive symptoms.39 These positive results persisted for one year following hip fracture.40 Exercise interventions that focus on balance and strength, and include weight-bearing activities, have shown effectiveness for reducing subsequent fractures.41,42
Pharmacologic interventions can increase BMD and effectively prevent subsequent fractures. Patients who have difficulty taking an oral bisphosphonate, either for medical reasons or compliance issues, may be treated with an infusion of zoledronic acid (in conjunction with calcium and vitamin D); this form of therapy following hip fracture has been shown to significantly decrease both the incidence of a new clinical fracture and the mortality rate.43 Additionally, a recent pooled analysis suggests that once-yearly infusions of zoledronic acid 5 mg reduces the incidence of new clinical fractures in women age 75 years and older who are documented to have osteoporosis or have had a recent hip fracture.23 It should be noted, however, that adverse events were more common in the group receiving zoledronic acid than in the group receiving placebo.
Post-hip fracture rehabilitation can be considered another form of secondary prevention since the primary goal of rehabilitation following a hip fracture is to return the patient to his/her pre-fracture functional status. Variable results have been reported in the literature regarding best practices for hip fracture rehabilitation, due to disparate techniques of rehabilitation practices and nonstandard design of studies evaluating the efficacy of rehabilitation techniques.44 Nevertheless, the extant literature suggests that rehabilitation in a variety of forms and levels of intensity following hip fracture has beneficial effects. For instance, results from a recent meta-analysis that included 55 randomized trials and 25 nonrandomized trials indicated that improvement in ambulatory abilities was frequently associated with post–hip fracture rehabilitation.44 Other positive outcomes associated with rehabilitation following a hip fracture included improvements in functional recovery, strength, balance, and lower-extremity power. The authors concluded that postoperative monitoring by a geriatrician and intensive occupational therapy and physical therapy were effective modalities for improving post-fracture functioning.44
Individuals with cognitive impairment are more difficult to rehabilitate, due to problems with compliance and ability to complete assigned tasks necessary for optimal recovery. For this reason, cognitively impaired individuals have largely been excluded from randomized trials for fall prevention strategies. It remains unclear whether cognitively impaired individuals can benefit from fall prevention programs24; however, even a limited program aimed at preventing contractures, maintaining muscle mass, and improving techniques for transfer and mobility has merit.
Conclusions
Hip fractures continue to be a major challenge to both individual and societal health, and will continue to grow in magnitude as our population ages. Future generations of older persons will hopefully be better able to handle traumatic incidents without injury because of better bone health. Even here, regardless of how strong one’s bones may be, trauma may take its toll. While interventions that have studied particular populations have already demonstrated efficacy in preventing hip fractures and their consequences, these need to be further tested in larger populations and adopted as public health initiatives if we are to see any major benefit. Research hopefully will continue to identify new approaches to the treatment and rehabilitation of individuals who have suffered a hip fracture in order to improve quality of life and reduce the burden of this major problem to individuals, their families, and society.
Acknowledgment
Dr. Andersen was supported by National Institutes of Health Grant T32 GM075767-01A1.
The authors report no relevant financial relationships.
Dr. Andersen is from the National Study Center for Trauma and EMS, and Dr. Osei-Boamah is from the Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine. Dr. Gambert is Professor of Medicine and Co-Director, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Director of Geriatric Medicine, University of Maryland Medical Center and R Adams Cowley Shock Trauma Center, and Professor of Medicine, Division of Gerontology and Geriatric Medicine, Johns Hopkins University School of Medicine, Baltimore, MD. Dr. Stein is Chief of Critical Care, R Adams Cowley Shock Trauma Center, and Associate Professor of Surgery, Department of Surgery, University of Maryland School of Medicine.
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