CLINICAL FEATURE KEYWORDS Hip fractures / Elderly / Co-morbidity / Pain / Venous thromboembolism Provenance and Peer review: unsolicited contribution; Peer reviewed; Accepted for publication January 2011.
Perioperative implications of surgery in elderly patients with hip fractures: an evidence-based review by Jonathan J E White, Wasim S Khan and Peter J Smitham Correspondence address: Wasim Khan, UCL Institute of Orthopaedics and Muscuioskeletal Sciences, Royal National Orthopaedic Hospital, Stanmore, Middlesex, HA7 4LP. Email:
[email protected]
Hip fracture is a major cause of morbidity, mortality and ioss of independence for tine eideriy. Surgicai fixation of the fractured Inip remains the standard of care to aliow for eariy mobilisation and a return to independence. Operative management in this population carries its own set of problems. The altered physiological state of the older person, often coupled with significant comorbidity, can present challenges for the anaesthetist, the surgeon and the rest of the perioperative team. This article provides an evidence-based review of the important perioperative factors associated with hip fractures in the older person and their management. Hip fractures are frequent injuries amongst older patients with osteoporosis and account for about 76,000 cases in the UK per year according to the National Hip Fracture Database (NHFD 2010). A review that examined the extensive hip fracture literature published in the English language between 1980 and 2009 concerning hip fracture prevalence trends suggested that hip fractures will remain a serious global health issue (Marks 2010). Hip fractures are a major cause of morbidity, mortality and loss of independence in the elderly. These fractures pose a major public healthcare burden and continue to consume large portions of healthcare resources. Surgical fixation of fractured hips remains the standard of care to allow early mobilisation and a return to independence. Timely surgery limits the period of recumbence and helps to prevent pressure sores, urinary tract infections, deep vein thromboses and pulmonary complications including atelectases, pneumonia and pulmonary emboli. Surgical intervention is considered superior in medically-fit elderly patients (Parker et al 2000, Beaupré et al 2005), and ideally this should be completed within 48 hours for the majority of patients
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with hip fracture (Egol & Strauss 2009). Even in the absence of co-morbidity, the altered physiological state of the older person can present challenges for the anaesthetist and the rest of the perioperative team. Operative management in this population carries its own set of problems and implications, and these are discussed below. Fractures of the neck of femur could be divided into extracapsular and intracapsular fractures. Extracapsular fractures are generally treated with fixation using a dynamic hip screw or intramedullary nailing. Although undisplaced intracapsular fractures are also generally treated with fixation using cannulated screws, there is controversy regarding the optimal management of displaced intraarticular fractures. Most elderly patients with displaced intraarticular fractures are managed with a hemiarthroplasty and do well. However, there is increasing evidence to suggest that a total hip replacement improves patient functional outcomes for healthy, independent, elderly patients compared with hemiarthroplasty and should be considered as the treatment of choice for these patients as it is more predictable, durable and cost-effective in the longer-term
(Schmidt et al 2005, Malik et al 2009, Lowe et al 2010). A detailed discussion on the surgical management of these fractures is beyond the scope of this review.
Preoperative medical considerations The key difference between elderly patients and their younger contemporaries is a loss of functional reserve and a general decline in organ function (Muravchick 2000). Although age is not an independent risk factor for post-operative complications, the perioperative period is filled with increased risk secondary to the higher incidence of coexisting disease in the elderly. Older patients may present with an array of comorbidities involving any organ system and these must be evaluated and optimised prior to surgery to improve the postoperative outcome. This highlights the crucial roles played by both anaesthetists and geriatricians in the perioperative management of this challenging patient population. The risk of postoperative complications in the elderly hip fracture patient is proportional to the number of co-morbidities present. Roche et al (2005), in a
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A number of studies have sought to identijy specific co-morbidities predictive of increased postoperative mortality
prospective cohort study of 2,448 geriatric patients with hip fracture, evaluated the relationship between preoperative comorbidity and the risk of postoperative complications and mortality. The authors found that the presence of three or more preoperative co-morbidities was the strongest predictor of increased mortality at 30 days postoperatively, followed by respiratory disease and malignancy. The most common postoperative complications were chest infection (9%) and cardiac failure (5%). These findings underline the j importance of effective medical assessment and optimisation in the perioperative period. A number of studies have sought to; identify specific co-morbidities predictive ofj increased postoperative mortality. Mortality data at 30 days (Nettleman et al 1996), six months (de Luise et al 2008) and one year post-injury (Penrod et al 2008) have identified a history of congestive cardiac failure (CCF), chronic obstructive pulmonary disease (COPD) and/or malignancy as strong positive predictors. Nettleman et al (1996), in a retrospective analysis of 390 elderly patients with hip fracture, found that 63% of inpatient mortalities were cardiovascular in nature.
The American Association of Anaesthetists grading The American Society of Anaesthetists (ASA) developed a grading system (I to V) to classify patients according to their physical status, thus serving as an indicator of anaesthetic and surgical risk. A norrnal, healthy individual with minimal risk is deemed ASA class I, whereas a moribund patient who is not expected to survive 24 hours regardless of surgery is designated ASA class V (AAGBI 2001). The ASA score is a useful predictor of long term mortality after hip fracture (Michel et al 2002, Richmond et al 2003, Bjorgul et al 2010). In a prospective study of 1,635 patients with hip fracture, Bjorgul et al (2010) demonstrated that survival rates vary significantly between ASA classes. Over a five to ten year period postoperatively, survival for ASA I was 8.5 years versus only 1.6 years for ASA IV. Use of the ASA classification to predict postoperative
mortality risk can be further enhanced by complementing it with the Short Potable Mental Status Questionnaire (SPMSQ) for assessing cognitive function. Soderqvist et al (2009), in a prospective cohort study of 1,944 patients aged 66 or older, revealed that the combination of ASA score and SPMSQ provides greater information about survival times compared with the ASA score alone. In addition to mortality, the risk of medical complications can be predicted using the ASA class. In a retrospective analysis of 197 elderly patients with hip fracture, Donegan et al (2010) reported that medical complications were more common in those with ASA classes III and IV compared with ASA class II. Furthermore, patients classed as ASA IV were over seven times more likely to have medical complications compared with those in class II. These complications are numerous, and in a retrospective study of 8,930 patients aged 60 or over with hip fracture, Lawrence et al (2002) listed cardiac and pulmonary complications as most frequent (8% and 4% respectively). Other complications included gastrointestinal bleeding (2%), venous thromboembolism (1%), and transient ischaemic attack or stroke (1%). In another series of 1,010 patients evaluated by Ranhoff et al (2010), the most common complications were anaemia requiring transfusion, delirium and urinary tract infections.
Surgical complications Surgical complications include superficial wound infections, deep joint infections, hip dislocations, periprosthetic fractures, failure of fracture fixation, neurovascular injuries and leg length discrepancies. Most of these complications need further surgical interventions. Although no study has determined a link between age and complications, the number of co-morbidities is proportional to the risk of postoperative complications (Roche et al 2005) and elderly hip fracture patients are more likely to have co-morbidities. The reduced functional reserve and general decline in organ function seen in the elderly patients (Muravchick 2000) makes it more difficult for them to cope with the increased
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physiological demands of the complication and the possible surgical intervention that it may require.
Postoperative pain control The provision of adequate analgesia for hip fracture patients is essential, not only to allow for effective ambulation postoperatively, but also to help prevent complications. The pain induced by trauma and surgery leads to decreased mobility, and this in turn leads to reduced respiratory effort causing atelectasis and pneumonia. Decreased mobility also predisposes to urinary tract infections, deep vein thromboses and pulmonary emboli. Poor postoperative pain control can lead to a vicious cycle in which the pain itself is compounded bythe patient's own anxieties, thus limiting progress even further. Although some evidence exists regarding the most appropriate analgesia for patients with hip fracture, better analgesic control for the elderly needs to be discovered (Beaupré et al 2005). Poorly controlled pain however, increases the length of hospital stay, delays mobilisation, and reduces long-term functional ability (Morrison et al 2003). It is likely that complications arise secondary to impaired cognition, medical co-morbidities, and altered drug metabolism and pharmacokinetics. These factors make effective pain control in the older population far more complex than their younger counterparts. Acutely, postoperative pain management with intravenous morphine can be safely achieved using the same protocol as for younger patients. There appears to be no difference in the incidence of morphinerelated complications or sedation (Aubrun et al 2002). Several days postoperatively however, opioid requirements amongst elderly patients drop in comparison (Gagliese et al 2000). It is important that regular pain assessments are made to allow for adequate dosing adjustments, in addition to a baseline assessment upon arrival to hospital. Furthermore, special consideration must be given to cognitivelyimpaired patients, whose pain control is often suboptimal due to self-reporting of less pain. Behavioural pain indicators do n o t ©
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Perioperative implications of surgery in elderly patients with hip fractures: an evidence-bcised review Continued
however differ between cognitively-impaired and cognitively-intact patients, supporting the use of behavioural assessments in the cognitively-impaired (Horgas et al 2009). Another strategy to ameliorate this may be the adoption a standardised protocol for pain management (Adunsky et al 2002). Regional analgesia via the epidural route may provide a novel technique for managing acute postoperative pain in elderly hip fracture patients, although more research is needed, Foss et al (2005) examined the effect of four days postoperative epidural infusion of bupivacaine and morphine versus placebo in 60 elderly hip fracture patients, Epidural analgesia was found to be significantly superior in managing postoperative pain during all basic physical functions compared with controls. Despite the improved pain relief, there was no significant difference in scores for recovery of physical independence. These findings demonstrate that epidural analgesia provides enhanced pain control over standard regimens, but further studies are needed to elicit whether this improvement translates into enhanced recovery.
Pressure ulcer prevention The development of pressure sores after hip surgery is a common occurrence, with a reported incidence ranging from 9% to 55% (Gunningsberg et al 2000, Baumgarten et al 2003). It carries a great burden of morbidity as patients that develop pressure ulcers are at increased risk of developing nosocomial infections and other hospital complications, as well as enduring a significantly longer hospital stay (Allman et al 1999). The assessment and management of a pressure ulcer requires a systematic, comprehensive and multidisciplinary approach. Assessment of an elderly hip fracture patient includes the patient's comorbidities, functional state, nutritional status, and degree of social and emotional support (Jaul 2010). Vigilant nursing care can reduce this risk, through visual inspection, frequent turning, and the application of topical preparations. Furthermore, the implementation of heel protection and pressure-relieving mattresses can provide additional benefit. In a prospective randomised controlled trial assessing the benefits of an interface
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pressure-decreasing mattress, Hofman et al (1994) found that the incidence and severity of pressure ulcers were significantly reduced compared with a standard hospital mattress (24% versus 68%). Currently there is no research evidence that high-tech pressure-relieving mattresses are more effective than low-tech foam mattresses for the prevention of pressure ulcers. There is also a lack of evidence regarding the benefit of heel protection devices. Professional consensus recommends their use, but further research is needed.
Venous thromboembolism prevention Hip fracture is a major risk factor for venous thromboembolism (VTE) throughout the perioperative period. Other significant risk factors include malignancy, coagulopathy, immobility, previous VTE, obesity, stroke, atherosclerosis, and ASA grade > 3 (Beksac et al 2006). Advanced age is weakly associated with the development of VTE (Abad Rico et al 2010). Incidence rates for deep vein thromboses range from 36% to 60% (Ennis 2003), whilst those of pulmonary embolism range from 4% to 24% (Egol & Strauss 2009). Fatal pulmonary emboli occur in 1% to 13% of cases (Ennis 2003). Despite extensive research on an optimal thromboprophylaxis strategy, there remains no agreement on a standard protocol. The Pulmonary Embolism Prevention (PEP) trial (PEP Trial Collaborative Group 2000) assessed the effect of aspirin versus placebo for VTE prophylaxis in 13,365 patients with hip fracture. Treatment with aspirin reduced the risk of both symptomatic deep vein thromboses and pulmonary emboli when compared with placebo (29% and 43% respectively). There was an increased transfusion requirement in patients assigned aspirin, however mortalities due to bleeding were comparable between study groups. Based on the findings, the authors concluded that treatment with aspirin decreased the incidence of deep vein thromboses and pulmonary emboli by one third
perioperativelyand should be used routinely in patients with hip fracture, A retrospective study by Ennis (2003) of 1,000 consecutive hip fractures compared the use of aspirin with the low-molecularweight heparin (LMWH), enoxaparin. Although there was no significant difference in deep vein thrombosis rates between the treatment groups, there was one case of fatal pulmonary embolism in those treated with aspirin and no pulmonary emboli recorded with enoxaparin. Considering its short half-life, predictability and favourable safety profile, the author concluded that enoxaparin, and thus LMWH, was an ideal form of thromboprophylaxis, A total of 32 trials covering 3,614 adult hip fracture cases have shown that unfractionated heparin and LMWH protect against VTE (Handoll etal 2002, Eriksson & Lassen 2003). In a Cochrane review by Handoll et al (2002) however, there was insufficient data to confirm a protective effect against pulmonary emboli. No significant differences were established between unfractionated heparin and LMWH. Eriksson & Lassen (2003) found that fondaparinux (factor Xa inhibitor) conferred a relative reduction in the risk of VTE (including pulmonary emboli) of 96% when compared with placebo. The incidence of symptomatic VTE was also found to be significantly lower in patients treated with fondaparinux and there was no increase in the incidence of clinically significant bleeding. Turpie et al (2002) reported a meta-analysis of four randomised, double-blind trials comparing the prophylactic effects of fondaparinux and enoxaparin in 7,344 cases of hip fracture. Fondaparinux was shown to confer a significantly greater protective effect against VTE than enoxaparin, with an odds reduction of 55%. It was also shown to significantly reduce the incidence of proximal deep vein thromboses with a reduction of 57%. The risk of clinically relevant bleeding was low and did not differ significantly between the treatment groups. In a retrospective study by Shorr et al (2007) of 144,806 patients who had undergone major orthopaedic surgery.
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Unfortunately, postoperative delirium has received little attention in the perioperative literature, despite its considerable morbidity and mortality
including for hip fracture, the benefits of fondaparinux were further clarified.| Patients receiving fondaparinux experienced fewer VTE events (1.5%) compared to enoxaparin (2.1%), dalteparin (2.1%) and unfractionated heparin (4.2%). | Post-discharge, there remains a risk of delayed thromboembolic events, thus justifying the need for extended thromboprophylaxis (Anand & Buch 2007). Prolonged treatment with fondaparinux over a four week period can reduce the risk of DVT by 96% and the risk of symptomatic VTE by 89% compared with perioperative (one week) treatment (Kwong 2004). The American College of Chest Physicians recommends the routine use of fondaparinux, LMWH, or unfractionated heparin for patients undergoing hip fracture surgery. Their guidelines also reconr mend against the use of aspirin alone for thromboprophylaxis and encourage the use of physical methods of anticoagulation for patients with a high bleeding risk or as an adjunct to chemoprophylaxis (Geerts et al 2008).
Postoperative confusion/delirium Postoperative delirium is characterised by a disturbance of consciousness and temporary abnormalities in cognitioh and perception. It is a common problem in the elderly hip fracture patient with a postoperative incidence ranging from 5% to 61% (Edelstein et al 2004, Gustafson et al 1988). Risk factors for delirium include advanced age, pre-fracture cognitive and functional impairment, pre-existing cerebrovascular and other brain diseases, indoor injury, communication difficulties and social isolation (Duppils & Wikblad 2001, Juliebo et al 2009). Precipitating factors for delirium comprise perioperative falls in blood pressure, postoperative infections and malnutrition (Ediund et al 2001). Perioperative risk factors associated with postoperative delirium include intraoperative blood loss, electrolyte abnormalities and a postoperative haematocrit
