Fig. 5.1
The patient’s journey during TKA. OT occupational therapy, PT physiotherapy, GP general practitioner
Fig. 5.2
Example of an enhanced recovery programme. GA general anaesthetic, NSAIDs nonsteroidal anti-inflammatory drugs, PCA patient-controlled analgesia, MST morphine sulphate tablets, PPI proton pump inhibitor, IV intravenous, LA long-acting, * unless contraindicated
5.2.1 Preoperative Patient Education
Patient education is an effective method of managing expectations and has been associated with reduced anxiety and length of stay in addition to improved pain control in the postoperative period. It may be provided by specialist nurses and can be on a one-to-one basis [7] or in a group. It includes details of the surgical procedure, expectation and goal setting, symptom management, discharge date and the perioperative care plan. Various educational resources can be employed including booklets, care plans and educational videos. Other considerations include the organisation of postoperative support and psychological and organisational preparedness.
5.2.2 Prehabilitation
There is some evidence to suggest that preoperative exercise may help improve functional capacity and physiological reserve [8]. However, a recent meta-analysis did not show any significant effect on functional recovery after joint replacement, although the limitations stated included low therapeutic validity of the exercises and the studies included in the review were somewhat heterogeneous [9]. There would appear to be some face validity to the concept of improving muscle bulk, power and control preoperatively in order to speed recovery, although exercises may be limited by the patient’s knee condition and general health.
5.2.3 Nutrition
The nutritional status of the patient plays a role in postoperative recovery and wound healing [10] and identification and treatment of patients who are at risk can be undertaken using the Malnutrition Universal Screening Tool [11]. Similarly, anthropometric measures including triceps skinfold can be used which has been shown to have an inverse relationship to postoperative infection after TKA [12]. Low biochemical markers such as serum transferrin, albumin and total lymphocyte count have also been associated with longer recovery times and length of stay after TKA [13, 14]. Individuals who are deemed to have a nutritional deficit can be provided with appropriate nutritional supplements, and those who are at a higher risk of nutritional deficiency should be referred to a dietician prior to surgery.
5.2.4 Other Preoperative Factors
5.3 Reducing Blood Loss
Minimising bleeding and blood loss are important in reducing transfusion rates and the potential risks associated with this in addition to reducing costs and maintaining blood stores. Transfusion rates in TKA can be as high as 20 % and can therefore have a significant impact. Strategies aimed at reducing blood loss can be initiated at the preoperative assessment to identify patients at increased risk. Intraoperatively, bleeding can be minimised by meticulous surgical technique and haemostasis in addition to specific anaesthetic techniques. Similarly, postoperative measures can also be valuable.
5.3.1 Preoperative Strategies
The preoperative assessment and thorough history should aim to identify any coagulation disorders or drugs such as anticoagulants and anti-platelet agents. Doses may need to be changed or certain drugs discontinued and in high-risk patients either continued or a bridging plan implemented [20]. Other drugs that can effect bleeding include nonsteroidal anti-inflammatories and selective serotonin reuptake inhibitors and even some herbal medications containing garlic or ginseng which have an anti-platelet effect and therefore should be considered for discontinuation.
Coagulation disorders may require specific treatment and optimisation or one may need to consider specific anaesthetic and surgical techniques and on occasions preoperative review and advice from a haematologist. Coagulation factors may be indicated in certain patients with haemostatic disorders, for example, factor XIII concentrate in cases of deficiency and prothrombin complex concentrate in patients with liver disease who have coagulopathy.
5.3.2 Intraoperative Strategies
Various intraoperative strategies are available to help reduce blood loss. However, their ability to reduce transfusion rates is somewhat variable.
Computer-assisted surgery has been shown to reduce blood loss after TKA, but this did not have a significant effect on transfusion rate [21].
Spinal or epidural anesthesia has been shown to reduce blood loss in various surgical procedures in comparison to general anesthesia [22]. However, Macfarlane et al. [23] reported no difference after TKA in a systematic review of 28 studies. Thus, the effect of general anesthesia or regional anesthesia on blood loss remains controversial.
Hypothermia can alter platelet function and the clotting cascade leading to increased bleeding and transfusion requirements. A drop in temperature of less than 1 °C has been shown to increase blood loss by 16 % and relative risk for transfusion by 22 % [24]. It is therefore critical to maintain normothermia employing warming blankets and warmed fluids where possible.
Controlled hypotension can also be useful in reducing blood loss in orthopaedic surgery [25]. However, there is a risk of inadequate perfusion of vital organs and therefore the hypotension must be closely monitored.
Antifibrinolytics can be a useful adjunct in reducing surgical blood loss and transfusion requirements. Intravenous administration of tranexamic acid is most often used and has been shown to have similar effects in reducing transfusion rates regardless of whether a high (135–150 mg/kg) or low dose (15–35 mg/kg) was used [26]. More recently, it has been applied directly to the surgical field with a resultant reduction in blood loss over placebo [27]. Tranexamic acid has not been associated with increased thromboembolic complications, but concerns remain about the risk of symptomatic thromboembolic events, particularly when a less aggressive chemical prophylaxis method such as aspirin alone is employed. These concerns have not been borne out by a recent large retrospective study of 2,046 patients who underwent primary THA and TKA [28].
Fibrin sealant can help reduce transfusion rates by as much as 55 % [29] in TKA. Fibrin sealants have been shown to maintain a higher postoperative haemoglobin and may therefore be a useful adjunct in reducing blood loss [30].
Techniques of cell savage and acute normovolaemic hemodilution (ANH) can also be used to reduce blood loss. Cell salvage using washed or filtered autotransfusion systems can help reduce transfusion requirements [31], although the efficacy in TKA remains debatable. ANH involves predonation of blood by the patient immediately before surgery and replacement of the circulating volume with crystalloid or colloid, any blood loss thereafter being reduced by the hemodilution. The donated blood can then be re-transfused at the end of the procedure. These techniques are more likely to be helpful when the anticipated blood loss is predicted to be high which is unlikely in primary TKA although a case could be made for revision surgery where a tourniquet is not used.
5.3.3 Postoperative Strategies
There is still some debate regarding the use of surgical drains in TKA. It has been shown that transfusion rates can be increased if drains are used in lower limb arthroplasty including TKA [32]. If a drain is used, then consideration should be given to clamping the drain intermittently (for greater than 4 h) which has been shown to decrease blood loss [33]. In addition, blood loss into drains can also be reduced with local injection of bupivacaine and adrenaline [34]. Reinfusion drains are often used in TKA and can be a very useful technique in reducing transfusion rates [35] with a relative risk reduction of up to 60 % compared to a control group [36]. However, if other blood conservation techniques are used such as tranexamic acid, then reinfusion drains may be unnecessary [37].
5.4 Thromboprophylaxis
Patients undergoing TKA are at a significantly increased risk of venous thromboembolism. The incidence of symptomatic VTE is as high as 10 %, and the incidence of asymptomatic VTE is as high as 40–60 % [38, 39]. Despite this there remains controversy as to the ideal thromboprophylaxis measures. Thromboprophylaxis measures include both mechanical and pharmacological strategies and can be instituted at the preoperative stage. All patients should undergo a VTE risk assessment. Based on patient- and surgery-related factors, patients can then be assigned as low, intermediate or high risk, and this can be balanced against the risk of bleeding or other complication. All patients should receive basic measures including avoidance of dehydration, early mobilisation and lower limb range of motion exercises. The National Institute for Health and Care Excellence (NICE) in the UK has produced comprehensive guidelines (Fig. 5.3) for VTE prevention in orthopaedic surgery [40, 41]. Mechanical VTE prophylaxis should be combined with pharmacological means and for elective TKA the latter should be continued for 10–14 days. Pharmacological VTE prophylaxis can include either low molecular weight heparin (LMWH), fondaparinux, dabigatran or rivaroxaban. The choice of pharmacological prophylaxis is often determined by local policies.
Fig. 5.3
Venous thromboembolism (VTE) prophylaxis based on the National Institute for Health and Care Excellence (NICE) guidelines. LMWH low molecular weight heparin
5.4.1 Mechanical Thromboprophylaxis
Graduated compression stockings are also routinely used unless there exists a contraindication such as significant peripheral vascular disease. Thigh-length stockings may be more effective in reducing VTE than below-knee stockings [42]. Other options include foot pumps and intermittent pneumatic calf compression which when combined with pharmacological agents have an additive effect [43, 44].
Inferior vena cava filters may be appropriate for a selected group of high-risk patients where anticoagulation is contraindicated or where they have sustained a VTE despite anticoagulation. There are, however, significant complications associated with IVC filters, and their use should be carefully considered.
5.4.2 Pharmacological Thromboprophylaxis
Unfractionated heparin (UFH) is often reserved for patients who are at high risk of thromboembolism and have other nonsurgical-related risk factors such as mechanical heart valves. UFH requires monitoring of coagulation and inpatient treatment. In addition it can be associated with thrombocytopenia and osteopenia.
Low molecular weight heparins (LMWH, e.g. enoxaparin) are commonly used after TKA and should be started 6–12 h after surgery. They are derived from UFH via fractionation and work by inhibiting factor Xa and indirectly affecting thrombin. LMWH have a more predictable bioavailability and are usually administered subcutaneously at a fixed dose on a once-daily basis. LMWH have been shown to be as effective as UFH in reducing the risk of VTE and have the added benefits of once-daily dosing and reduced risk of heparin-induced thrombocytopenia.
An alternative is fondaparinux which is a synthetic pentasaccharide that inhibits factor Xa in an antithrombin-dependent manner. It may be more effective at reducing the risk of VTE than LMWH but has a higher risk of causing bleeding [45]. If used, it should be started 6 h after surgical closure.
Other parenteral anticoagulants include heparinoid, danaparoid and lepirudin and desirudin which are recombinant hirudins which are not commonly used in orthopaedic surgery.
Oral anticoagulants after TKA have gained popularity over recent years primarily because of their ease of use and administration. These include dabigatran (started 1–4 h after surgery) which is a direct thrombin inhibitor and apixaban and rivaroxaban which inhibit thrombin and factor Xa. Rivaroxaban (started 6–10 h after surgery) may in fact be more efficacious compared to enoxaparin [46].
Other forms of oral thromboprophylaxis which are not commonly used include aspirin (acetylsalicylic acid) and warfarin (vitamin K antagonist) which requires monitoring of coagulation parameters and dose adjustments in addition to requiring initial loading and has a narrow therapeutic window.
5.5 Reducing the Risk of Infection
One of the great challenges in arthroplasty is the prevention, diagnosis and management of prosthetic joint-associated infections. Prosthetic joint infection (PJI) and its consequences have a considerable impact on patients and lead to physical disability, significant emotional morbidity and increased mortality [47].
It places an enormous burden on health service provision along with a huge economic impact. The key to avoiding the consequences of infection in TKA is prevention.
5.5.1 Preoperative Strategies
Many factors in patients’ preoperative condition have been associated with an increased risk of infection after TKA including diabetes [48], poor nutrition, old age, body mass index of greater than 30 and prolonged hospital stays, in addition to previous surgery and trauma [49]. Other factors that have been associated with an increased risk include previous steroid injection [50], rheumatoid arthritis [51], dental infections and infection elsewhere in the body [49]. It is therefore vital to identify these potential risk factors preoperatively and treat them appropriately. In addition, as mentioned above, nutritional optimisation is important as is smoking cessation.
The commonest cause of infection in prosthetic joints is Staphylococcus aureus, and screening for methicillin-resistant Staphylococcus aureus (MRSA) and, depending on local protocols, methicillin-sensitive Staphylococcus aureus (MSSA) may be a useful exercise. The use of decolonisation protocols is well established and usually includes topical intranasal mupirocin and chlorhexidine washes [52]. This is an extremely valuable and cost-effective method of reducing infection due to Staphylococcus aureus [53].
5.5.2 Intraoperative Strategies
Surgical etiquette in theatre is important in ensuring infection prevention. Theatre personnel should be kept to the minimum necessary as they are a significant source of bacteria [54, 55]. All theatre personnel should have hair covered including beards, and strict adherence to surgical attire, masks and hats should be followed. Body exhaust systems can also reduce infection risk [56–58].
Appropriate handwashing with aqueous Betadine or chlorhexidine is important in reducing bacterial load. Alternatively, hand rubbing with alcohol-based solutions can be employed. The operating staff should also double glove as this reduces the risk of inadvertent contamination through perforation of the gloves and allows regular changing of the outer glove.
Skin preparation of the surgical site and draping should be performed meticulously. Alcohol reduces bacterial load very effectively, but it does not have sustained effect. Other preps include povidone-iodine and chlorhexidine gluconate which can be combined, e.g. ChloraPrep. Draping with disposable nonwoven drapes acts as a more effective barrier to bacteria than cloth drapes. In addition plastic adhesive iodine-impregnated drapes can also be useful in reducing recolonization.
Preoperative hair removal has not been associated with reduction in infection rates but if necessary should be performed immediately prior to surgery and with trimmers which do not touch the skin to reduce the risk of injury to the epidermis.
Laminar flow and ultraclean-air systems are also used routinely and can reduce PJI (Table 5.1), vertical laminar flow being more effective than horizontal laminar flow [57]. Charnley reported a reduction in the incidence of deep infection from 7 to 0.5 % in a series of 5,800 total hip arthroplasties [59].
Table 5.1
Factors effecting deep joint infection after TKA
Prophylactic measure | Factor by which incidence of infection was reduced |
---|---|
Ultraclean air
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