Scheduled for elective primary unilateral total knee arthroplasty (TKA) with robotic surgery
Able to speak and understand Cantonese or Mandarin or English
Able to provide informed oral and written consent
You may not be if
Revision TKA
Single-stage bilateral TKA
Complex primary TKA requiring use of stem/augment/constrained liner
Surgeries with significant intraoperative complications which may alter rehabilitation protocol eg collateral ligament injury, fracture requiring fixation
Known allergy to opioids, local anaesthetic drugs, paracetamol, non-steroidal anti-inflammatory drugs (NSAIDS) including COX-2 inhibitors
History of chronic pain other than chronic knee pain
History of immunosuppression
Chronic use of glucocorticoids
Chronic opioid use (morphine, fentanyl, hydromorphone, ketobemidone, methadone, nicomorphine, oxycodone, or meperidine)
History of congestive heart failure (NYHA 2)
Alcohol or drug abuse
Impaired renal function (defined as effective glomerular filtration rate \< 30ml/min/1.73m2
Impaired liver function (defined as plasma bilirubin over 34mol/L; international normalized ratio \[INR\] \>= 1.7, alanine aminotransferase \[ALT\] over 100U/L, aspartate aminotransferase \[AST\] over 100U/L)
Coagulopathy (platelet count \<100,000/ml and/or INR \>= 1.5) or the use of anticoagulants (not including aspirin) that precludes the use of adductor canal blocks
Pre-existing neurological or muscular disorders
Psychiatric illness
Impaired mental state
Pregnancy
Local infection
On immunosuppressants
High body mass index (BMI) (\>=40)
Patient refusal for regional nerve blocks or to conduct clinical trial
