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The-Knowledge Base for Key Clinical Issues in Hip Fracture DEFINITIONS The term hip fracture is something of a misnomer. It actually refers to a fracture of the upper end of the thigh bone (femur). The anatomic characteristics of hip fractures are important for three reasons. First, the hip joint and its attached muscles are critical in the ability to stand and to wale Second, this part of the skeleton is subject to complex forces and stresses during the activities of daily living. These forces and stresses are very different from those that occur during a fall. The hip, in effect, is designed to withstand the stresses associated with daily living but is poorly designed to withstand the impact from a fall. Third, the location of the fracture, as well as its severity, influences the choice of therapy (i.e., type of surgery). Fractures are categorized into one of three groups according to what part of the bone is involved (see Figure 1~. One group involves the femoral neck, which is just below the head of the femur. Another involves fractures around the intertrochanteric crest; this bane links the greater and lesser trochanters, which are prominent bony eminences situated essentially between the femoral neck and the upper part of the main shaft of the femur, to which the major skeletal muscles are attached. Subtrochantenc fractures start at or below the lesser trochanter and involve the femoral shaft itself. A final important aspect of hip fracture is the effect of the fracture and subsequent treatment and healing on the acetabulum, which is the cup- shaped depression in the pelvis into which the head of the femur fits. Of concern is pre-existing damage or deformity of the acetabulum or injury to the cartilage resulting from the fracture or subsequent treatment. In such cases the socket does not provide a smooth or congruent receptacle for 8
Least Severe \ 30° / Femoral Neck Fracture Intertrochanteric Fracture to=, ~ Greater A Trochanter <' // \ Lesser Trochanter ~V: / Subtrochanteric Fracture FIGURE 1 Examples of Main lopes of Hip Fracture 9 Most Severe ~\N ) 'Con I'm' l VY \ )41\ 11.',~ ,
10 EFFECTIVENESS INlTLATl~E cases the socket does not provide a smooth or congruent receptacle for the femoral head, and this may significantly influence the type of treatment selected. EPIDEMIOLOGIC AND CLINICAL ASPECTS OF HIP FRACTURE The investment in hip fracture research is large and growing. A1- though efficacy studies contribute immensely to the lmowledge base, results of those studies do not address all the major clinical questions and pop- ulation groups. One reason for selecting patient management topics for effectiveness studies, therefore, is to identify the remaining unanswered questions and to determine whether they can be addressed by alternatives to RCIs. Several subjects, which are briefly reviewed here, provided the context for the committee's discussions of those unanswered questions.) They in- clude epidemiology, risk factors and prevention, surgery issues, nonsurgical treatment options, and rehabilitation. Epidemiology Frequency Hip fracture causes significant morbidity and mortality. There are 260,000 hip fractures in the United States each year, and they occur almost entirely among elderly people.2 The medical, social, and economic consequences for hip fracture victims are severe, for instance, resulting in an excess 1-year mortality of 12 to 25 percent, impaired ambulation, and institutionalization for 33 percent or more of hip fracture survivors. In some studies, as many as 50 percent of hip fracture victims require long-term care for the rest of their lives. Total direct medical care costs are estimated to be $6 billion per year, much of which is reimbursed by Medicare or Medicaid. i] Demographic Aspects Hip fracture risk is related to age, sex, and race. Incidence rates women are nearly twice those in men. Rates in whites are greater ~ This section is based on materials submitted by several members of the committee who have special expertise in hip fracture. In part it reflects information Contained in the literature cited in the bibliography at the end of this report. Ibe topics themselves were not debated during the workshop. 2The annual incidence of hip fracture among people age 65 and older, of whom there are 31,800,000, is 8.2 per 1,000.
HIP FRACTURE 11 than those in Hispanics, which, in turn, are greater than those for Asians and blacks. Incidence rises dramatically with age; in North America and northern Europe, it begins to rise at about age 40 and doubles every 5 to 7 years through age 90. Rates approach 6 per 1,000 women per year for those between the ages of 75 and 79, 21.4 per 1,000 for those between the ages of 85 and 89, and 48.6 per 1,000 for those over age 90. For white women over age 85, rates as high as 30 to 50 per 1,000 per year have been observed. Relationship to Aging The interaction of hip fracture and age is not well understood. Some individuals are described as "doing really well until they broke a hip and went downhill quickly." For them, the hip fracture was the "beginning of the end," a signal of compromised ambulation, greater risk of post-surgical complications, especially delirium, an increased sense of frailty3 associated with the fear of falling, and of need for use of an aid in walking. At the other extreme, hip fracture may signal an "end of the beginning," a clinical manifestation of aging and frailty that was previously subclinical or the cumulative effect of small declines reaching a threshold that precipitates the hip fracture. Most clinicians suspect that both perspectives are valid. For some patients hip fracture is a precipitating event, and for others it signals decline that is well underway. There are different implications depending where in relation to these conditions a particular individual is. If the fracture is an acute injury that can precipitate a major decline in an otherwise intact individual, treatment strategies must be developed accordingly and adverse side effects or inadequate rehabilitation must be avoided. If, by contrast, it reflects a clinical manifestation of decline, the patient might not be expected to return to prefecture levels of functioning. Other aspects of choice of treatment and long-term support then come into play. Research is needed to determine how to classic patients and how to apportion scarce resources to achieve the maximum recovery level for each patient. As people age, changes occur in the cardiovascular, musculoskeletal, and neurological systems, and they occur at different rates. Subtle physio- logical changes over time influence the susceptibility threshold or margin of safety against severe (or even minor) illness, that is, an individual's 31be term frailty is used throughout this report but has no specific meaning. The term is a shorthand for any one or more of a set of attributes or circumstances that are associated with an unusually high probability of some adverse event, hip fracture in this instance. The task of identi- fying specifically the determinants of the adverse event of fracture is the first step in the research agenda. Determining elective ways to alter risk-promoting attributes i.e., prevention is the second step.
12 EFFECTIVENESS INITIATIVE ability to return to homeostasis after physical or biological trauma. These are all considered physiological changes, not frailty per se. Being able to assess these changes and relate them to probabilities of outcomes will enhance the medical profession's ability to select appropriate interventions and treatments rather than making decisions based largely on age. Risk Factors and Prevention of Hip Fractures lathe concept of postponement is critical in the prevention of hip fracture. Given the exponential increase in the hip fracture rate (doubling every five to seven years) with age, the incidence of the condition might be reduced by as much as 50 percent if the onset of this exponential rise could be uniformly postponed by only five years. This suggests that important opportunities for prevention exist within the Medicare population if the risk factors for hip fracture could be better understood. For example, a person who enters Medicare at age 65 will have an 8-fold to 16-fold increase in the risk of hip fracture over the next 20 years. Even a moderate reduction in the progression of these incidence rates could reduce both suffering and costs. Most hip fractures result from moderate trauma, usually a fall from a standing height. Thus, the risk factors for hip fracture include those for falls and those for sustaining an injury during the fall (such as decreased bone strength resulting from osteoporosis and the severity of the fall itself). Prevention must focus on reducing the risk of falls, on reducing the injury potential of those falls that do occur, and on increasing bone strength. Falls Falling is a common event for elderly people. Between 30 and 50 percent of the elderly surer at least one fall per year, and a subset of this group is at risk for more frequent falls. Those in the latter group have the highest risk of fracture. A major determinant of whether a fall results in a fracture is thought to be bone strength, although other factors such as the type of fall (e.g., direction and site of impact),4 muscle mass, and protective 4 Some experts argue that falls and, in particular, the severity of the fall (including its direction, site of impact, and use of protective mechanisms) may well dominate fracture risk in comparison with issues of bone strength and osteoporosis. Data are not yet available to allow a simultaneous assessment of both bone density and fall severity; this is a critical question because its answer influences the potential efficacy of intervention efforts aimed at maintaining bone strength, re- ducing falls, or reducing the severity of falls that do occur. Intervention efforts aimed at either maintaining bone strength or reducing the number of falls have not conclusively shown signifi- cant reductions in hip fracture incidence. It remains to be seen whether interventions aimed at reducing the injury potential of falls would be as or more effective.
HIP FRACTURE 13 responses during the fall are also important. Falls are caused by various combinations of environmental, intrinsic, and activity-related factors. As many as half of all falls involve environmental conditions such as structural hazards, icy sidewalks, inadequate lighting, frayed rugs, and electrical cords. These factors are less important in precipitating falls in institutionalized populations. Host factors include acute or chronic disease (such as Parkinson's disease), mental or necrologic impairment, abnormalities of gait or balance, muscle weakness, and use of certain medications. A small percentage of falls result from a single, overwhelming event such as fainting. Psychotropic medications have been consistently associated with a two- to-three-fold increase in the risk of falls and hip fractures. Geriatricians advise that psychotropic drugs should be prescribed only when they are absolutely necessary, that doses be as low as possible, that they be given for the shortest possible duration, and that selected drugs within a therapeutic class be used. For example, if a benzodiazepine is prescribed, then one of the drugs with a short half-life should be chosen. Although evidence from controlled trials is not available, one can reasonably assume that careful assessment and targeted interventions may decrease the risk of elderly people falling. This involves identification of the presence and severity of certain diseases and disabilities, especially problems of sight, balance, necrologic functioning, musculoskeletal deficits, and systemic disease. Assessment also involves identification of relevant medications and environmental factors. It calls for careful observation of balance and gait and review of previous fall situations. Based on such assessment, a combination of medical, rehabilitative, and environmental interventions may help prevent hip fractures without compromising func- tioning and morbidity. Intervention strategies to reduce the severity of falls should also be considered. Bone Mass and Osteoporosis Fracture pathogenesis is complex and involves abnormalities that are intrinsic and extrinsic to the skeleton. Low bone mass is the most critical skeletal abnormality relating to hip fracture. Osteoporosis is the gradual loss of bone mass with aging. Although the pathophysiology of osteoporosis is incompletely understood, it may arise from disorders of the physiologic systems that regulate calcium balance. Risk factors associated with osteoporotic fractures include white race, female sex, post-menopausal status, low body mass index (weight over height squared), sedentary life-style and physical inactivity, and possibly alcohol and tobacco use. Diet and nutrition, especially calcium intake
14 EFFECTIVENESS INITIATIVE during rapid growth, climate, and genetic factors may also influence bone mass. Continued research is needed on these and other risk factors. The major determinant of bone loss among early post-menopausal women is estrogen deficiency; osteoporosis can be retarded and bone loss largely prevented with estrogen replacement therapy. Late in life, calcium deficiency may develop because of insufficient calcium intake and calcium malabsorption. Common wisdom has been that the prevention of osteoporosis must begin early in life because available therapies can preserve bone mass but cannot replace lost bone to any great extent. The protective effects of instituting osteoporosis prevention measures for women in their 40s and 50s, especially estrogen replacement therapy, may be dramatic in reducing the incidence of hip fractures among women in their late 80s and 90s. Medications have complex effects on bone mass. As implied above, estrogen replacement therapy decreases the risk of hip fracture in newly menopausal women, but whether it has similar benefits for women age 65 and older is unknown. Thiazide diuretics, which decrease urinary calcium loss and which are used commonly, have been associated with increased bone mass and decreased hip fracture risk in people aged 65 and older. For some individuals, however, thiazide diuretics may cause orthostatic hypotension (especially in the initial phase of therapy) resulting in fainting when rising from a seated or horizonal position and hence raising the risk of falls. Other potential therapies include the antiresorptiYe agents calcitonin and biphosphonates. Anticonvulsants, corticosteriods, and replacement thyroid hormone may increase bone loss and, thus, increase fracture risk. Clinical trials and other research efforts are needed to quantify the risk of hip fractures associated with use of these medications, assess potential prophylaxis, and identify less hazardous alternative therapies. Surgical Issues Several different treatment options exist for each type of hip fracture, and professionals are uncertain as to which technique consistently offers the best outcome. Before 1930, the treatment options for a patient with a fractured hip consisted of bed rest with traction, cast immobilization, or simple mobilization with disregard to the fracture. With the advent of internal fixation in the 1930s, operative management became the preferred method of treatment unless the risks of surgery were prohibitive. Surgical approaches at the time consisted of a single nail or multiple pins for treatment of a fractured femoral neck or a nail-plate combination for intertrochanteric and subtrochanteric fractures. These approaches led to earlier mobilization of the patient and lowered mortality significantly.
HIP FRACTURE 15 Failure of the fracture to heal, a source of continued complications, prompted the development of a prosthesis to replace the femoral head. Use of this prosthesis allowed immediate weight-bearing without requiring the lengthy convalescence needed for union of the bone itself. Nevertheless, in the 1950s and 1960s, complications with femoral head replacement persisted, including unexplained postoperative pain in the hip and a high infection rate. With the advent in the 197Qs of total hip replacement techniques (sometimes called total hip arthroplas~, which is a procedure in which the acetabulum and the femoral head are both replaced), yet another treatment became available for the management of fractured hips.5 The advantages of total hip replacement included, as before, early weight-bearing without the need to wait for bony union, -more consistent relief of pain, and elimination of the acetabular erosion that occasionally occurred with the simple femoral head replacement. The disadvantages included a more complex operation and considerably more expensive implantable devices. Surgical Treatment Options Although several surgical treatment options are available, clinicians generally agree that open reduction and fixation of the fracture fragments are the appropriate treatments for intertrochanteric and subtrochanteric fractures. A major controversy relates to defining objectively the appropri- ate treatment options for 'femoral neck fractures. The options are briefly described below. Intertrochanteric Fractures Intertrochanteric fractures are nearly always treated with some form of internal fixation and an implanted device such as a pin and 'plate or intramedullary rods (rods that run along the center of the bone and that stabilize the fracture fragments). Because this is frequently a difficult fracture to manage, multiple surgical approaches are used, but in virtually all'cases the patient's own bone stock is preserved. The most commonly used fixation device for an intertrochanteric fracture is a collapsible nail plate or screw plate device that allows bone impaction (i.e., the bone being pressed together by ambulation after surgery into a stable position). 5Total hip replacement is performed for reasons other than fractures, for instance, to reduce severe pain or significant constraints on physical mobility owing to problems with the hip joint and, perhaps, to forestall possible falls should the hip joint give way suddenly secondary to severe deterioration. Although the appropriate indications for total hip replacement are themselves a matter of controversy, the focus of this report is on the clinical condition of hip pactwe and the relationship of total hip replacement as a therapeutic intervention for that clinical event.
16 Subtrochantenc Fractures EFFECTIVENESS INITIATIVE The use of intramedullary devices is now recommended for treatment of the true subtrochanteric fracture. This requires open reduction and internal fixation of the fracture. More complex approaches such as in- terfragmentary fixation (screwing multiple fragments together) or cerclage wiring (tying fragments together) are often needed to reconstruct a stable bony situation to prevent subsequent shortening of the leg. In certain severe cases, bone grafting is recommended. Femoral Neck Fractures Fractures of the femoral neck are classified on radiographs in four "Garden stages"6 (in ascending order of severity): I, incomplete or im- pacted fracture; II, complete but nondisplaced fracture; III, complete and partially displaced fracture; and IV, complete and totally displaced fracture. Different treatment options exist, depending on the stage. Although clini- cians agree that most of these fractures should be treated surgically, they do not agree about the type of surgery. The original approach to femoral neck fracture was to use some form of internal fixation device such as a nail or a nail and plate. This technique is still used, but the incidence rates of non-union (failure of the fracture to heal) and of avascular necrosis of the femoral head (i.e., decay and death of bony tissue owing to the lack of needed blood supply) well over 20 percent are significant. Furthermore, both problems, singly or in combination, produce a poor result and may require further surgery, leading to replacement of the femoral head. For these reasons, many orthopedic surgeons elect to treat femoral neck fractures of the Garden III and Garden IV stages almost routinely with some form of prosthetic replacement. Anatomic reduction and stable internal fixation produce the best long- term outcome (in terms of bone strength) when healing occurs primarily. This is the most common way to treat Garden stage I and II fractures and is associated with a high rate of success. The shift of the bone fragments is very little and the blood supply is usually intact. If reduction is necessary, it is achieved by closed means if possible. If not, open reduction is carried out. Although two- and three-point fixation with multiple pins appears to offer better stability and long-term outcomes than the use of one large pin 6This classification system is different and more detailed than the taxonomy presented in Figure 1. Garden stage I is an incomplete fracture a so-called impacted fracture. Garden stage II fractures are complete but undisplaced. Garden stage III fractures are complete and displaced but the fragments remain in contact with each other. Complete displacement occurs in Garden stage IV.
HIP FRACTURE 17 (according to some orthopedists), excellent results have been obtained with either method of fixation. Controversy exists in use of the treatment options available for the more severe Garden stage III and IV fractures. Few useful criteria exist to assist a practitioner in determining when and under what circumstances a particular displaced femoral neck fracture should be reduced and internally fixed, treated by primary hemiarthroplasty (replacement of the femoral head with a prosthesis as the primary procedure), or treated by primely total hip arthroplasty. One disadvantage of internal fixation of the fractured femoral neck has been the need for the gradual resumption of full weight-bearing. Elderly patients have difficulty with balance, with manipulation of crutches or walkers, and with understanding the concepts of partial weight-bearing and bone healing. For that reason, the alternatives of femoral head replacement or total hip replacement have certain advantages. Specific indications for the last two treatment options are present in individuals with Parkinson's disease, Alzheimer's disease, or severe osteoporosis. nvo major questions arise about treating femoral neck fracture. First, is internal fixation or replacement of the femoral head the best treatment method? Second, is total hip replacement being carried out in patients with appropriate indications? With respect to internal fixation, issues include the extent of healing, non-union rates, avascular necrosis, and other com- plications. For prosthetic replacement, issues include complications such as dislocation, infection, loosening, and need for reoperation. Although at the extremes of the distribution of femoral neck fractures the indications for appropriate treatment may be fairly clear, there are no data to guide treat- ment selection for the large majority of fractures. Most physicians elect to treat femoral neck fractures based on their own personal experience. The utility of this approach needs to be evaluated. Managing Postoperative Complications and Ambulation Historically, better postoperative management of patients with hip fractures has helped to reduce death rates from hip fractures. In the past decade, however, despite advances in treatment, the one-year mortality of 12 to 25 percent over the norm has remained high and unchanged. The practice of ambulating patients as soon as possible after surgery has significantly lowered the incidence of thrombophlebitis and consequent pulmonary embolism (clots that obstruct blood circulation); the latter can be life-threatening. Early mobilization probably remains the single most effective method for reducing the incidence of these complications. Var- ious other prophylactic measures are also employed, including the use
18 EFFECTIVENESS INITIATIVE of antiembolism stockings, continuous passive motion of the hip, and anti- blood-clotting medications such as coumarin and heparin. Special attention to the nutritional status of patients may also be important. Early ambulation has a direct impact not only by forestalling certain medical complications but also by increasing the potential for the individual patient to return to his or her prefecture environment. Limited ambula- tion can force an elderly individual who enjoyed independent living to be admitted to a managed living environment. Nonsurgical Treatment Issues With the many advances in medical care and technology over past decades, physicians are now confronted with a group of very elderly, infirm patients with moderate to severe mental and functional impairments who sustain hip fractures. These injuries frequently occur in protected envi- ronments such as nursing homes and hospitals. Orthopedic surgeons have continued to apply the accepted standard of care to patients with these injuries that essentially all such patients should operated upon. Although firm data are not available, experienced clinicians believe that the results of surgery in these debilitated patients are usually poor and that complication rates are high. Many of these patients die within a short period of time, although not necessarily during the acute hospitalization. Further, patients in this category may continue to suffer from significant postoperative symptoms, remain severely impaired functionally, and fre- quently never return to their prior functional level. Epidemiologically, such patients tend to include: · very elderly patients · patients residing in nursing homes or other protected environments · patients with moderate or severe mental impairment or dementia · bedridden or severely physically disabled patients · patients with severe or progressive comorbid conditions. Given the poor expectations for many of these patients, it is appropriate to ask whether they should be treated surgically at all. Instead they might be given nonsurgical care that focuses on alleviation of pain, prevention of complications, and ease of care-giving. The problem from an ethical point of view is that the outcome in unoperated patients is almost always predictably poor, with multiple complications, continued pain, and possibly death occurring in a short period of time. One question is whether it is possible to identify a group of patients in whom the outcomes of surgery are virtually certain to be so poor that nonoperative support treatment only should be rendered. This question involves measurement of the medical
HIP FRACTURE 19 and functional aspects of treatment and attention to the patient's and family's desires (e.g., the right to refuse surgical treatment). Rehabilitation The goal of rehabilitation is to return an individual to as normal a life as possible. For elderly people with hip fractures, the goal is to return them to the same level of independence and activity that existed before their injury. Rehabilitation addresses not only the ability of individuals to wale and perform other activities requiring mobility. It also concerns their opportunity to live independently; to function within the community; to participate in social activities; and to continue other activities they might wish to perform. Many services can be offered: effective limb and joint mobilization and alignment; passive resistive exercises of nonaffected joints; other physical therapy and occupational therapy to regain mobility and independence; restorative nursing services (e.g., range-of-motion exercises) as a follow-up phase to active rehabilitation; training in major areas of life function (such as mobility and self-care); physician monitoring of care or progress; and psychological support when indicated. The optimal setting to provide these rehabilitation services for a particular patient depends on four factors: the number of problems needed to be addressed to achieve full rehabilitation; the severity of functional deficits; the severity of any comorbid conditions; and access to alternative services and settings. Rehabilitation programs can vary significantly by the type of insti- tution, comprehensiveness of services, intensity of program delivery, and rehabilitation goals. Institutions include acute-care hospitals, rehabilitation hospitals or units, long-term-care facilities (skilled nursing and intermediate care), outpatient facilities, and homes. Some address only mobility through physical therapy services. Others address mobility, self-care, community activities, social and psychological adjustment, recreation, and other goals through the services of a wide array of professionals physicians, nurses, psychologists, physical therapists, occupational therapists, social workers, recreational therapists, and others. The goals of a given rehabilitation program determine its compre- hensiveness and intensity. Some individuals with hip fracture may receive monthly physician visits in association with biweekly physical therapy treat- ments. Other patients receive services from multiple therapists twice a day during the initial period of their rehabilitation. These needs, in turn, usually influence the setting in which the services are delivered. Some individuals may go directly home from the hospital and receive home or outpatient rehabilitation care. Others may go through a series of institutions, such as
20 EFFECTIVENESS INITL4TIVE the rehabilitation hospital or unit or the skilled nursing facility, or both, before receiving services in the home setting. Because of the enormous variation in these aspects of rehabilitation, decisions regarding the site and intensity of rehabilitation services should be determined through an assessment of the needs of the individual that establishes clear rehabilitation goals. However, the availability of insurance (or the extent of covered benefits in Medicare), the desire of the patient, and the preferences of individual physicians who manage the acute phases of injury of the individual with a hip fracture may influence these decisions. Nevertheless, both historical and clinical experience suggests that active rehabilitation that focuses broadly on the various needs of an individual results in better outcomes than does more limited services. At present, most rehabilitation professionals believe it is preferable for an individual to receive comprehensive services in a setting somewhat more intense than necessary, rather than risk having a patient fail to receive comprehensive services because of efforts to reduce short-term costs.