Key points

  • Patients with a hip fracture have a relatively high risk of perioperative morbidity and mortality, related to their age and co-morbidities.

  • High-quality care requires timely, integrated patient management by a multidisciplinary team, including surgeons, anaesthetists, geriatricians, nursing staff, occupational therapists, physiotherapists, and others.

  • Early surgery facilitates effective analgesia and allows early mobilization, and is associated with reduced morbidity and mortality.

  • The mode of anaesthesia provided is less important than the manner with which it is delivered with regard to the age and pathophysiological status of the individual patient.

  • Perioperative anaemia is common; anaesthetists should assess haemoglobin levels in the immediate postoperative period.

Although the annual incidence of hip fracture in the UK appears to be decreasing, the number of patients sustaining a hip fracture annually is predicted to increase in line with the ageing demography of the population, from 77 000 cases in 2009 towards 100 000 cases in 2033, with concomitant increases in inpatient financial costs from ∼£0.8 billion to ∼£2.7billion (inflation adjusted) over the same time period (outpatient and social costs double these figures).1 Three-quarters of hip fractures occur in women, and the median age at fracture is 84 yr. Hip fracture is more common in Northern compared with Southern Europeans, and is becoming more prevalent among the non-European population as increased wealth improves longevity. Simple mechanical falls from standing height in patients with pre-existing osteoporosis are the most common cause of fracture; patients are often prone to falling, and are more likely to fall in future after hip fracture fixation.

Approximately 98% of hip fractures are managed surgically, as fixation provides the best analgesia and chance of rehabilitation, and reduces the risk of complications such as pneumonia and pulmonary embolism.

Hip fracture can be viewed as a symptom of declining physiological function with age, in combination with co-morbidity; 70% of patients are ASA III or IV, 25% have at least moderate cognitive impairment (abbreviated mental test score <7, complicating communication, resuscitation, and consent discussions), 20% reside in a residential or nursing home, and 50% require walking aids or are immobile. Polypharmacy against a background of age-altered pharmacokinetics increases the risk of drug interaction and side-effects, contributing to further falls.

Outcomes are relatively poor and have not improved greatly over the last 20 yr: the postoperative mortality rate is ∼8% at 1 month2 and ∼30% at 1 yr, ∼20% suffer at least one significant complication after operation, and only about one-third of patients return to their pre-fracture level of daily function. The median length of inpatient stay is 23 days, which is comparable with 10 yr ago.

There has been considerable political and professional interest in improving the clinical and financial outcomes of patients with hip fracture in the UK over the last 7 yr. The rigorous Scottish Hip Fracture Audit (www.shfa.scot.nhs.uk) informed the production of clinical guidelines in Scotland concerning the management of hip fracture in 2002 (updated in 2009),3 which in turn informed joint British Orthopaedic Association (BOA)/British Geriatric Society guidelines in 2007.4 These led to the formation of the National Hip Fracture Database, data collection for which contributes to hospital Trusts' qualification for ‘best practice tariff’ uplifts that reward quality patient care with extra financial income. Despite professional guidance, there remains considerable variation in clinical and organizational practices across the UK, resulting from a lack of strong evidence for best practice management of hip fracture, a problem repeatedly alluded to in the National Institute for Health and Clinical Excellence's guidelines (CG124—http://guidance.nice.org.uk/CG) produced in 2011, and re-iterated in the guidelines that inform professional anaesthesia standards, namely the AAGBI's Management of Proximal Femoral Fractures 2011.5

All guidelines emphasize several common themes: effective management requires a prompt, coordinated, multidisciplinary approach, delivered by senior personnel, using integrated care pathways that standardize care while allowing for individualized treatment according to co-morbidity and organizational differences. Rather than act as passive gatekeepers of access to surgery, anaesthetists, as the most appropriate providers of perioperative medical care, should always become actively involved in the preoperative evaluation and postoperative optimization of hip fracture patients, in order to minimize the secondary physiological insult of surgery. The AAGBI guidelines provide links to a number of tools that may assist with these aims, including a specimen integrated care pathway proforma and patient information sheet, a skeleton audit database and report, ideas for specific hospital audits, and an ‘A–Z’ guide for junior surgeons to facilitate the provision of preoperative management in order to expedite surgery.

Rather than restate the AAGBI guidelines, the remainder of this article addresses specific dilemmas in the anaesthetic management of hip fractures.

Preoperative assessment and delay to surgery

‘Prehabilitation’ defines the idea that inpatient management should have appropriate discharge from hospital as its primary aim; surgery and perioperative care forms an early stage in this process. Preparation for surgery should begin as soon as the diagnosis of hip fracture is suspected; although this raises the future prospect of pre-hospital diagnosis with direct paramedic to ward admission, the Department of Health and BOA currently recommend Casualty department to orthopaedic ward transfer within 4 h, and surgery within 36 h of hospital admission, allowing a period for preoperative evaluation and acute treatment.

No study has so far shown that ‘preoptimization’ improves outcome among hip fracture patients, whereas two large meta-analyses of ∼275 000 patients have shown that delay to surgery beyond 48 h is associated with increased 30 day postoperative mortality, complications, and length of inpatient stay. Anecdotally, the involvement of orthogeriatricians in preoperative management has improved the preparation of patients for surgery, through improved communication with surgeons and anaesthetists, and 87% of patients in the UK (excepting Scotland) currently undergo operation within 48 h of hospital admission. Despite the emphasis on expedited surgery, there are serious co-morbidities for which the benefits of 24–48 h of medical treatment before surgery may outweigh the risks of delay (Table 1).

Table 1

AAGBI recommendations concerning acceptable and unacceptable reasons for delaying surgery. Note that the ‘acceptable’ reasons for delay are not absolute

May be acceptable Unacceptable 
Severe anaemia <8 g dl−1 Lack of facilities or theatre space 
Severe electrolyte imbalance, plasma Awaiting echocardiography 
 [Sodium] <120 or >150 mmol litre−1 Unavailable surgical expertise 
 [Potassium] <2.8 or >6.0 mmol litre−1 Minor electrolyte abnormalities 
Uncontrolled diabetes  
Uncontrolled/acute left ventricular failure  
Correctable cardiac arrhythmia, ventricular rate >120 bpm  
Chest infection with sepsis  
Reversible coagulopathy  
May be acceptable Unacceptable 
Severe anaemia <8 g dl−1 Lack of facilities or theatre space 
Severe electrolyte imbalance, plasma Awaiting echocardiography 
 [Sodium] <120 or >150 mmol litre−1 Unavailable surgical expertise 
 [Potassium] <2.8 or >6.0 mmol litre−1 Minor electrolyte abnormalities 
Uncontrolled diabetes  
Uncontrolled/acute left ventricular failure  
Correctable cardiac arrhythmia, ventricular rate >120 bpm  
Chest infection with sepsis  
Reversible coagulopathy  

Predicting mortality

Most hip fracture patients are ASA III, limiting the use of the ASA score as a tool for predicting postoperative outcome in these patients. The Nottingham Hip Fracture Score (NHFS, Table 2) is a tool which has been specifically developed and validated to predict mortality 30 days after hip fracture surgery6 (and in subsequent studies has been shown to predict both 1 yr mortality and discharge destination). If validated by other hospitals, the NHFS will have several important applications, enabling, for example, the estimation of outcome risk in discussion with patients, relatives, and surgeons, case mix adjustment when comparing hospitals with each other or hospital performance over time, and case mix description for the purposes of research. Perhaps of greatest importance is that the score will enable accurate identification of the high-risk patient, who is most likely to benefit from early surgery and, possibly, high dependency care.

Table 2

NHFS used to predict mortality

Variable Points Score Predicted 30 day postoperative mortality (%) 
Age 66–85 yr 
Age 86 yr or older 
Male 
Hb≤10 g dl−1 on admission to hospital 
Abbreviated mental test score≤6/10 on admission 
Living in an institution 10 
More than one co-morbidity 15 
Active malignancy within last 20 yr 23 
  33 
  45 
  10 57 
Variable Points Score Predicted 30 day postoperative mortality (%) 
Age 66–85 yr 
Age 86 yr or older 
Male 
Hb≤10 g dl−1 on admission to hospital 
Abbreviated mental test score≤6/10 on admission 
Living in an institution 10 
More than one co-morbidity 15 
Active malignancy within last 20 yr 23 
  33 
  45 
  10 57 

Echocardiography

The management of patients with hip fracture in whom a systolic murmur [indicating aortic stenosis (AS)] is heard remains contentious. Traditionally, anaesthetists have been reluctant to administer anaesthesia without additional echocardiographic information concerning aortic valve area, transvalvular gradient, and left ventricular contractility (indicated by ejection fraction), for fear of producing cerebral and coronary hypotension and ischaemia through arteriolar relaxation in patients with a relatively fixed, stenotic cardiac output, consequent to spinal (and general) anaesthesia.

Guidelines have consistently stated that echocardiography is indicated if it has not been performed recently. However, despite the prevalence of AS being higher in the population with hip fracture (∼20–40% vs 3% in the over 75s, possibly contributing to the aetiology of the fall), several studies have found that early postoperative mortality among patients with AS undergoing hip fracture is similar to hip fracture patients without AS, although higher mortality has been noted in other studies. Insistence on preoperative echocardiography has declined in recent years; however, as this can delay surgery, and the information yielded rarely changes management, which should be to treat patients with an audible ejection systolic murmur as if they had at least moderate AS, and administer anaesthesia accordingly, that is: using invasive arterial pressure monitoring and vasopressors to maintain coronary and cerebral perfusion pressure, and delivering anaesthesia sympathetically to the patients age and co-morbidities.

Perioperative analgesia

Hip fracture is painful. At rest, approximately one-third of patients with a fractured hip will have mild (or no) pain, one-third will have moderate pain, and one-third will have severe pain. On movement, however, over three-quarters will have moderate to severe pain, and so it is essential to monitor both static and dynamic pain scores, before and after analgesia administration. Third-person assessment scales are available for determining pain levels in those 25% of hip fractures with impaired cognition who may not be able to communicate their pain.

Extracapsular fractures (i.e. those requiring dynamic hip screw or proximal femoral nail operations) are more painful than intracapsular fractures (i.e. those requiring hemiarthroplasty or hip replacement), due to the greater degree of periosteal damage.

Analgesia should be provided throughout the perioperative period, beginning in the pre-hospital setting with immobilization and i.v. opioid administration. Multimodal analgesia is necessary, but with an inpatient emphasis on avoiding opioids and non-steroidal anti-inflammatory drugs (NSAIDs). Opioids are associated with increased postoperative confusion, which prolongs inpatient stay through delayed mobilization; furthermore, ∼40% of hip fracture patients have at least moderate chronic renal impairment (estimated glomerular filtration rate <60 ml min−1 1.73 m−2), placing them at relatively higher risk for opioid toxicity. NSAIDs further reduce renal function, and increase the risk of gastrointestinal haemorrhage. Regularly administered paracetamol is very effective, but codeine and tramadol should be avoided.

Local anaesthetic nerve blockade reduces the dose of opioids necessary for analgesia. Sensory innervation to the hip joint and capsule are supplied by branches of the lumbar plexus (femoral nerve L2–4, obturator nerve L2–4, supero-anterior capsule) and the sacral plexus (sciatic nerve L4–S3, posteroinferior capsule), while the skin overlying the hip joint (through which surgical access to the joint is obtained) is supplied by the iliohypogastric nerve (L1), lateral cutaneous nerve of the thigh (L2, 3), the superior cluneal nerves (L1–3, posterolateral approaches), and rarely, the lower thoracic cutaneous nerves (Fig. 1). These nerves may be anaesthetized by local anaesthesia administered via a variety of approaches (e.g. femoral nerve, lateral cutaneous nerve of the thigh, fascia iliaca, and psoas blocks), either as a single dose or infused continuously via a catheter, the accuracy and efficacy of which may be increased by ultrasound guidance, nerve stimulation, or both. Increasingly, these blocks are being administered in accident and emergency departments by trained non-anaesthetic personnel, to reduce pain and opioid requirement in the preoperative period. They are also used as adjuncts to spinal and general anaesthesia, and should always be considered when the latter is administered.

Fig 1

Sensory innervation of skin overlying the hip joint. (Image reprinted with permission from Medscape.com, 2012. Available at: http://emedicine.medscape.com/article/1148690-overview.)

Fig 1

Sensory innervation of skin overlying the hip joint. (Image reprinted with permission from Medscape.com, 2012. Available at: http://emedicine.medscape.com/article/1148690-overview.)

Anaemia

On admission to hospital, ∼40% of hip fracture patients are found to have anaemia [World Health Organization definition of (Hb) <12 g dl−1 for females, <13 g dl−1 for males], resulting from a variety of causes, including haemorrhage from the fracture, haemodilution if i.v. fluids have been administered, malnutrition and anaemia secondary to chronic disease. Severe anaemia is rare, but may predispose to falling. Haemoglobin concentration decreases by ∼2.5 g dl−1 in the perioperative period. Based on WHO criteria, postoperative anaemia occurs in ∼90% of patients. It follows, therefore, that if a patient is anaemic before operation, then without transfusion, there is the potential for them to become dangerously anaemic after operation (indicating that these are the patients for whom preoperative crossmatched blood should be made available). Fitter patients may be able to tolerate haemoglobin levels around 10 g dl−1, but become symptomatic as the haemoglobin concentration decreases towards 8 g dl−1, a level which is associated with delayed mobility, prolonged inpatient stay, cardiac and cerebral ischaemia (the latter manifest as acute confusional state in the postoperative period), lightheadedness, and fatigue. However, patients with pre-existing cardiac or cerebral ischaemia may develop complications at haemoglobin concentrations of <10 g dl−1.

Whether or not to administer blood transfusion remains as contentious as the haemoglobin level used to trigger transfusion. Administering blood is associated with increased postoperative mortality, but it has proved difficult to determine whether this is cause or effect (i.e. whether sicker patients need more blood, or whether blood makes patients sicker), and even more difficult to determine what transfusion triggers to advocate. The FOCUS study (Functional Outcomes in Cardiovascular Patients Undergoing Surgical Hip Fracture Repair) has yet to report formally, but (in abstract) appears to show that among 2016 patients in 47 US and Canadian centres, there are minimal differences in postoperative return to mobility or 60 day mortality using a ‘liberal’ (Hb maintained >10 g dl−1) compared with a restrictive (Hb maintained >8 g dl−1) transfusion strategy.

In a recent questionnaire survey, the Hip Fracture Perioperative Network (www.networks.nhs.uk/nhs-networks/hip-fracture-anaesthesia) noted among 148 of its members that only ∼8% measured the patient's haemoglobin level immediately after operation; the AAGBI recommend pragmatically that all patients should be tested after operation using point-of-care devices (e.g. Hemocue), to ameliorate the potential for ischaemia occurring in the variable period until haemoglobin level is more formally tested after operation.

Clopidogrel

Linked to the aetiology of perioperative anaemia is the recent confusion concerning perioperative continuation of anticoagulant drugs, notably clopidogrel. Clopidogrel is a prodrug that irreversibly inhibits the P2Y12 subtype of ADP receptors, inhibiting platelet aggregation by blocking activation of the IIb/IIIa glycoprotein complex. Approximately 4% of hip fracture patients take clopidogrel or similar drugs, mainly for the prevention of coronary stent thrombosis, with or without aspirin.

Several recent studies have shown that although blood loss (and hence transfusion rate) is slightly increased among patients taking clopidogrel, mortality might actually be increased by stopping therapy perioperatively, particularly among patients with drug-eluting stents, due to acute coronary/stent thrombosis or delay to surgery.7 Patients do not require perioperative platelet transfusion unless clinically indicated, but should be monitored closely for postoperative anaemia. Spinal anaesthesia and lumbar plexus block are not absolutely contraindicated, but their use is sensibly limited to patients in whom the benefits of such interventions outweigh the risk of bleeding and spinal haematoma.

Method of anaesthesia

The dearth of large randomized comparison studies has led to a wide interinstitutional and interindividual variation in how anaesthesia is provided for patients with hip fracture. As a result, both audit and meta-analysis of anaesthetic practice have failed to show any great difference in outcome between general and regional (spinal) anaesthesia.

Parker and colleagues'8 Cochrane review of 2004 analysed 22 trials (all of which were found to be methodologically flawed), involving 2567 patients, and concluded that regional anaesthesia may reduce the prevalence of acute postoperative confusion (9% vs 19%), but that the reduction in 30 day mortality after regional anaesthesia compared with general anaesthesia was of borderline statistical significance. Based on these findings, the SIGN guidelines suggested that ‘Spinal/epidural anaesthesia should be considered for all patients undergoing hip fracture repair, unless contraindicated’.3

A more recent meta-analysis of 34 randomized controlled trials, 14 observational studies, and eight meta-analyses, involving 18 715 patients, concluded that although ‘the limited evidence available do(es) not permit a definitive conclusion to be drawn’, regional anaesthesia is the technique of choice, being associated with significantly reduced early mortality, deep vein thrombosis, acute postoperative confusion, myocardial infarction, pneumonia, fatal embolism, and postoperative hypoxia.9

There are numerous problems in trying to conduct the definitive outcome comparison study between general and regional anaesthesia, including, but not restricted to, definition of the primary endpoint (30 day mortality and length of stay are traditional, but temporally distant from the period of anaesthesia), equipoise (most anaesthetists will generally have better outcomes using their preferred technique), variation in each technique (e.g. GA/GA+block/GA+spinal/GA intubated/GA supraglottic device/GA inhalation/GA TCI, etc.) (spinal/spinal with sedation/‘plain’ spinal/‘heavy’ spinal/use of adjuncts, etc.), general perioperative care provision, operator experience, type of fracture, and day of admission. In order to correct for the effects of these, it has been estimated that such a trial would need in excess of 9000 patients allocated to either group. An alternative method may involve the analysis of large databases such as the National Hip Fracture Database, although account would have to be taken of inaccurate data entry.

In the interim, the AAGBI recognize that either method of anaesthesia (but not both together) may be used, but most importantly that they are administered sympathetically to any patient pathophysiology, using reduced doses of anaesthetic agent combined with multimodal analgesia to limit rapid fluctuations in arterial pressure and consequent changes in cerebral and coronary perfusion pressures. This concept is supported by a recent retrospective study of 1131 patients which demonstrated that a reduced volume of intrathecal 0.5% hyperbaric bupivacaine was associated with a reduction in intraoperative hypotension, and reduced reactive fluid administration with consequent haemodilution.10

The AAGBI also reiterate the finding in the NCEPOD reports Extremes of Age (1999) and An Age Old Problem (2010) that, despite being among the sickest patients with the worst outcomes in hospitals, elderly hip fracture patients were not intensively monitored during surgery, and suggest a far greater consideration be given to invasive arterial pressure monitoring and use of cardiac output (e.g. Doppler, LiDCO) and cerebral function (e.g. bispectral index, cerebral oxygen saturation) monitors.

Conclusion

Patients with hip fractures continue to present clinical and organizational challenges to the NHS, but outcomes appear to be improving, assisted by initiatives such as the National Hip Fracture Database. However, the evidence for anaesthetic intervention remains poor, and a multidisciplinary national research programme is needed to identify which outcomes are most appropriate as study endpoints, and which treatments are most effective in improving these.

Declaration of interest

S.W. is a member of the AAGBI hip fracture guidelines working party, and advised NICE during development of their hip fractures guidelines. He is a council member of the Age Anaesthesia Association, who he represents at the National Hip Fracture Database. He is national research co-ordinator for the Hip Fracture Perioperative Network.

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