Knee Arthroplasty

• Use of ERAS programmes for those undergoing knee arthroplasty:
• Reduces length of stay, especially in healthier patients
• No increase in perioperative complications
• Reduces blood transfusion rates
• Reduces complication rate, including mortality
• Day-case arthroplasty programmes can improve healthcare efficiency by reducing cancellations due to lack of beds, though requires protocolised practice, strong MDT working and consistent communication throughout

• Pre-operative exercise programmes and education are recommended ('joint schools')
• Home-based prehabilitation programmes may improve perioperative pain and function, although not necessarily length of stay
• Educational components help manage patient's expectations; education about post-operative pain can reduce opioid consumption by half

• Smoking cessation for at least 4 weeks
• Alcohol cessation programme if history of abuse


• Reduce perioperative fasting time
• Use 'sip-to-send' policy
• Preoperative carbohydrate loading

• AAGBI monitoring
• Patient usually positioned supine so no need to keep IV access to one side

• Regional techniques, be they neuraxial or peripheral, reduce post-operative pain and opioid-associated side effects
• The impact of regional techniques on perioperative blood loss is less than for hip arthroplasty as a tourniquet is usually used

• Spinal anaesthesia
• Bupivacaine (plain or heavy) and prilocaine are options; chloroprocaine may be too short-acting even for experienced surgical hands
• Typically need ~10mg bupivacaine e.g. 2ml 0.5% heavy bupivacaine
• Some centres have begun using higher-volume/lower-concentration spinals e.g. 3-4ml 0.25% bupivacaine
• Anecdotally this has a higher failure rate


• Intrathecal opioids
• Addition of intrathecal morphine (100μg) can improve post-operative analgesia vs. standard care for up to 16hrs post-op.
• Doses of 100μg or below are not associated with increased sedation or PONV
• Doses above 100μg may increase side-effects without providing additional analgesia
• Use of IT morphine is associated with higher rates of pruritus, urinary retention/catheterisation/UTI and sedation
• Overall not recommended, but may be useful in those having complex or revision hip arthroplasty, or those with complex pain syndromes


• Epidural/CSE is an option, especially for anticipated complex or revision cases


• ± procedural sedation
• E.g. propofol TCI, midazolam
• Patient-controlled procedural sedation is associated with fewer sedation-associated adverse events than anaesthetist-led TCI (BJA, 2021)

• The adductor canal block (subsartorial saphenous nerve block) has become the regional anaesthetic technique of choice
• Blocking the nerve to vastus medialis whilst performing the adductor canal block can provide further medial joint analgesia
• Surgical infiltration with LA + TXA ± NSAID
• iPACK blocks do not provide benefit above surgical LIA

• May be necessary in patients where neuraxial techniques are contraindicated, or have failed
• Requires alternative analgesia e.g. from regional techniques (see below) in addition to a standard multimodal analgesic regimen

• Tranexamic acid
• Usually 1g at induction, although there may be variable surgical requests regarding:
• Timing e.g. pre-tourniquet, prior to tourniquet release, further doses post-operatively
• Dosing e.g. 1g, 2g, 15mg/kg
• Route e.g. post-operative oral dosing
• NICE recommend IV TXA + 1-2g intra-articular TXA after the final washout


• Antibiotics as per local policy
• Intraosseous vancomycin may reduced perioperative joint infection


• VTE prophylaxis; typically 4 - 5 weeks of post-operative prophylaxis are required (LMWH, aspirin or DOAC)

• Knee arthroplasty is associated with more significant pain than hip arthroplasty owing to more extensive osteotomy and splitting of the quadriceps muscle
• High quality analgesia is associated with reduced time to mobilisation, reduced length of rehabilitation and reduced length of stay


• Paracetamol
• NSAID (if no contraindication)


• Dexamethasone
• PROSPECT guidance recommends a single dose of 8-10mg, some centres are using closer to 15-20mg and even higher doses have been trialled (e.g. 1mg/kg) (BJA, 2023)
• Use is associated with reduced pain, opioid consumption, PONV, fatigue and length of stay
• A second IV dose 24hrs post-op. confers additional benefit over a single dose without increasing side-effects or complications


• Consider intra-operative adjuncts such as:
• Ketamine 0.1-0.3mg/kg IV
• Magnesium 50mg/kg IV over 30mins

• Early mobilisation is encouraged

• Regular paracetamol 1g Q6H
• Reduces post-operative opioid consumption by 16-26% (NNT 3.6)
• NSAID with PPI cover if not contraindicated
• E.g. ibuprofen 400mg Q8H, celecoxib 200mg TDS
• Avoid in the first 48hrs if eGFR<60/CKD3
• Avoid entirely if eGFR<30/CKD4
• Avoid diclofenac or -coxibs in those with cardiovascular disease
• Consider nefopam in those not able to have NSAIDs
• Reserve opioids for rescue analgesia
• Avoid morphine-based opioids in renal failure; use oxycodone instead