Neck of femur (NOF) fractures/proximal femoral fractures are a common orthopaedic presentation. They present particular challenges for medical personal, and have a significant morbidity and mortality associated with them.
NOF fracture refers to a fracture of the femur within 5cm of the greater trochanter. They can be classified in several ways, with the most common being based on the anatomical location of the fracture:
Intracapsular fractures occur between the femoral head and the insertion point account for around 50% of NOF fractures. The fracture may affect the blood supply to the head of the femur. As such, if repaired or treated conservatively, there is the risk of avascular necrosis of the femoral head, resulting in a painful and poorly functioning joint.
Extracapsular fractures refer to fractures distal to the insertion of the capsule. This includes intertrochanteric and subtrochanteric fractures. Due to the higher blood supply of the cancellous bone, these fracture can be associated with significant bleeding.
The majority of fractures (90%) occur from a simple mechanical fall, from standing height. The main underlying risk factor is the presence of osteoporotic bone, resulting in a fracture.
The mechanism of injury can be considered based on the contributing factors:
Fall initiation - cognitive status, neuromuscular status
Fall descent - fall height, fall energy
Impact - soft tissue attenuation
Structural capacity of femur - bone density, bone geometry
Ultimately, the transmitted load is more than the structural capacity of the femur, resulting in the fracture.
Risk factors include:
NOF fractures are the most common reason for orthopaedic ward admission. Around 77,000 NOF fractures occur in the UK each year. The median length of stay is around 23 days. 30 day mortality has remained fairly static at 8-10%, but with significant inter-organisation variation.
95% of patients are over the age of 60. The majority (75%) of patients are female.
Around 98% of these will undergo surgical fixation.
The presenting complaint will commonly have been a fall from standing. Patients with significant cognitive impairment may not have got a clear history of a fall, but instead impaired mobility. The patient will be unable to weight bear on the affected leg. Pain is often located in the upper thigh or groin, but radiation to the knee is common.
The classic examination finding is a leg which is shortened, adducted and externally rotated. Flexion and rotation of the leg will induce pain
With NOF fractures being such a common presentation, there are national recommendations relating to the best way to allow organizations to care for these patients. Recognised approaches include:
Fast-tracked admission pathways
Dedicated trauma lists
Prioritisation of NOF fracture patients
Multidisciplinary team trauma meetings
Consultant delivered care
National guidance suggests the target of all patients with NOF fractures being admitted to an appropriate ward within 4 hours. The use of specific NOF fracture proformas and local pathways can help with this. It is advised that all patients have surgical fixation of their fracture within 48 hours. It is recognised that there are increased rates of complications beyond this (pneumonia, pressure ulcers, VTE events).
Specific trauma lists which now deal exclusively with trauma are common in many hospitals. Prioritisation of patients with NOF fracture on these lists is recommended to ensure that these cases are not postponed.
As these patients are often unwell with both acute physiological derangement and often not insignificant chronic comorbidity, they will often benefit from the most experienced clinician care. Consultant delivered care (both anaesthetic and surgical) is recommended. From an anaesthetic perspective, it is also recommended that such trauma lists are preferentially run by consultants with a special interest and experience in this patient group.
These patients will usually present to the ED. It is commonly an isolated injury, but full assessment will be based on the presenting complete e.g. major trauma, fall with head injury. A suitable systematic approach will therefore need to be applied.
The goals of ED management are:
Fast track admission
Multimodal analgesia is important for these patients. Regular paracetamol should be given unless contraindicated. NSAIDs are often relatively contraindicated in this patient group, who have a high rate of renal dysfunction alongside other comorbidities. Single shot nerve blocks (e.g. fascia iliaca blocks) can be very useful and are increasingly being employed in the ED. Opioids are often required but should be used with caution.
Plain film radiography is the diagnostic method of choice. An AP pelvic and lateral film can show disruption of the cortex, demonstrating the fracture. If an occult fracture is still suspected, then MRI is the recommended imaging of choice (although CT is an alternative).
A full assessment of the patient is required to identify any other problems. These are not uncommon in these patients, and include electrolyte disturbances, infections (as trigger for fall), and comorbidity. Early identification is essential to allow correction so that surgery isn’t delayed.
Active screening for cognitive impairment at admission is important to help with risk identification for postoperative cognitive dysfunction.
This is often dependent on the type of fracture, with other considerations.
Intracapsular fractures are often managed with a hemiarthroplasty. This is because of the high risk of avascular necrosis of the femoral head, and the adverse consequences of this. In undisplaced fractures, they may be suitable for conservative management, or internal fixation with screws. Patients with intracapsular fractures are at high risk of developing joint arthritis, even with hemiarthroplasty. As such, in younger patients or those with expectations of higher demands on mobility, there may be a decision for total arthroplasty. NICE recommends this if patients have decent mobility (mobilise outside with no more than a stick), no cognitive impairment, and are surgically and anaesthetically fit.
Extracapsular fractures, can be managed conservatively with traction and bed rest. However, this approach is associated with significantly worse morbidity and mortality, and so will almost always be managed by surgical fixation. As there are not the same concerns about blood supply, this may be through a dynamic hip screw (intertrochanteric fractures) or intramedullary nail (subtrochanteric fractures).
As noted, these patients often have significant comorbidity and need careful preoperative assessment. This should involve a full anaesthetic history, drug history and review of investigations.
Investigations should include:
Group & Screen - transfusion is not uncommon
CXR is not routinely indicated, but specific features e.g concern over a pneumonia, may warrant it.
Preoperative anaemia is common in these patients. There can be significant bleeding from the fracture site (extracapsular fractures being worse) with up to a litre of blood loss. This may then be compounded by haemodilution from IV fluid therapy. There is the suggestion that these patients may benefit from a higher transfusion threshold:
<10g/dl in patients with ischaemic heart disease
Patients with borderline Hb results should have blood crossmatched.
Coagulation abnormalities are not uncommon in these patients. Many patients will be taking antiplatelet agents. The impact of stopping these, including the risk vs balance of cardiovascular events against bleeding, must be considered. This may have particular impact on the use of neuraxial anaesthesia. Around 5% of patients are warfarinised. It is recommended that this should be reversed with vitamin K, and surgery continued when an appropriate ‘safe’ INR is achieved. Target INR ranges are <2.0 for surgery and <1.5 for neuraxial anaesthesia. Warfarin can be commenced 24 hours after surgery. Perioperative VTE prophylaxis will often be required.
Cognitive impairment is also common in this cohort of patients (Around 25% have moderate or severe). The consent process must take this into account.
The guidance suggests that waiting for investigation of incidental heart murmurs is not an appropriate reason to delay surgery. The concern here relates to the (albeit low) risk of undiagnosed aortic stenosis, with the significant impact on anaesthesia. If clinical examination provides strong evidence for this particular valvular lesion, then echocardiogram investigation is appropriate. However, if there is likely to be delay, then surgery should proceed with anaesthetic technique adjusted to take this possibility into account (e.g. awake arterial line, general anaesthesia).
There is still no clear evidence that a specific anaesthetic technique (neuraxial vs GA) has a better outcome. Neuraxial anaesthesia is commonly employed as the evidence does hint towards better outcomes. It is likely more related to the conduct of anaesthesia that a specific global approach.
Regional Regional anaesthesia is inadequate to provide operative depth anaesthesia, but can provide significant analgesia benefit for the postoperative period. The primary sensory innervation involves the femoral,obturator and lateral cutaneous nerve of the thigh. Blockade of these nerves can provide good initial postoperative analgesia. The common approach is the fascia iliaca block. The psoas compartment block is the most reliable method of blocking all 3 nerves but associated with higher risks (neuraxial spread, deep haematoma). Local infiltration of the wound does not provide adequate analgesia. Regional anaesthesia is recommended to minimise the opioid demands postoperatively.
FIB can be used in the anaesthetic room prior to spinal insertion, to allow optimal positioning for the spinal anaesthetic.
Neuraxial Neuraxial anaesthesia has a preference over general anaesthesia. This relates to evidence from a 2004 Cochrane review that suggested a lower rate of postoperative confusion. As such the SIGN and AAGBI guidance suggests that it be considered as the first anaesthetic approach unless contraindicated. Epidural anaesthesia may be able to provide postoperative analgesia, but this is at the expense of impaired mobilisation - As such it is rarely used, with spinal anaesthesia preferred.
Intrathecal opioids are generally avoided - there is a high risk of respiratory depression and post operative confusion in this cohort (as well as other adverse effects). If used, fentanyl (<25 mcg) is preferable, due to the improvement in block with a reduced postoperative duration of adverse effects.
Techniques to minimise the cardiovascular impact of spinal anaesthesia include:
Lateralisation of block - performing the spinal with the fractured hip inferiorly, focusing the block her
Low dose spinal - keeping the dose <10mg can reduce the degree of hypotension.
Doses of 1.5ml of 0.5% heavy bupivacaine can provide anaesthesia for around 2.5 hours and should be suitable for many cases. 1.8ml of 0.5% heavy bupivacaine have been recommended for total hip replacements. Wearing off at the end of the procedure can be mitigated by preoperative use of a FIB, which will provide coverage of the skin, allowing the stimulating suturing to take place. Many anaesthetists still use higher doses than this.
Combined general and neuraxial anaesthesia is not recommended because of the significant detrimental cardiovascular impact. Sedation can be administered, but should be done cautiously. It may be that sedation will undo any benefits of avoiding general anaesthesia, by resulting in more confusion, hypotension and respiratory depression. It may often be that no sedation is needed, as patients will sleep once spinal anesthesia is administered because of impaired sleep preoperatively, and preoperative opioids.
General anaesthesia A gentle general anaesthetic is another anaesthetic option. Both controlled and spontaneous ventilation techniques can be considered. Depth of anaesthesia monitoring can allow optimal cardiovascular stability in these patients whilst still providing adequate anaesthesia. Use of a regional technique (FIB) alongside general anaesthesia can reduce the anaesthetic requirements.
Monitoring Full AAGBI monitoring is essential. Because of the significant comorbidity encountered in this cohort, additional monitoring may be helpful:
Invasive arterial monitoring
Cardiac output monitoring
Patients can be vulnerable to hypothermia so active warming and monitoring of temperature is important. Additional oxygen therapy is commonly needed, especially with sedation.
Cardiovascular stability should be maintained throughout the surgery with the use of the usual vasoactive medications. Suggested targets include:
Within 25% of baseline
MAP > 60 mmHg
MAP values below 55 mmHg are associated with worse outcomes. It is important to remember that patients may be fairly dehydrated (from prehospital lies and fasting) and have lost a fair amount of blood, so careful attention to fluid balance is important.
Effective analgesia is important, though much of the analgesia comes from fixation of the fracture. Regional anaesthesia (e.g. fascia iliaca blocks) can be very helpful in this regard. Regular paracetamol should be given unless contraindicated. This cohort is at high risk of adverse effects from NSAIDs and they should generally be avoided, or used with extreme caution. They are also more sensitive to the adverse effects of opioids, and a multimodal analgesia approach should aim to minimise their use. Codeine is particularly avoided due to its constipating effects.
Venous thromboembolic disease (VTE) is common in this group. Mechanical and pharmacological prophylaxis is very important. This may be in the form of low molecular weight heparin or fondaparinux. This may impact on regional anaesthesia. Additional methods include:
Patients will commonly develop a degree of hypoxia postoperatively, and benefit from supplemental oxygen therapy.
Blood loss intraoperatively, as well as from the initial fracture, can be quite notable. Measurement of Hb values, with suitable transfusion, is an important factor to remember.
Postoperative cognitive dysfunction is very common in this cohort. Consideration and implementation of non-pharmacological measures is an essential part of delirium management. This includes aspects such as optimising sensory input (hearing aids, glasses, appropriate lighting), orientation, normalising physiology and good analgesia. Avoidance of deliriogenic drugs is important (benzodiazepines, cyclizine, tramadol).
Rehabilitation will form a significant component of the patients postoperative stay.
This remains a significant event for many people, with a high risk of morbidity and mortality. 30 day mortality is around 8.4%, with a 1 year mortality rate of between 15-30%. It is not uncommon for patients to require a higher degree of care following this injury. Only 44% of patients admitted from their own home will be able to return there within 30 days.