Comparison of Femoral Nerve Catheter and Adductor Canal Block With Steroid Adjuvant in Total Knee Replacement (TKR)

Comparison of the Analgesic Efficacy of Continuous Femoral Nerve Block and Adductor Canal Block With Steroid Adjuvant in Patients Undergoing Total Knee Arthroplasty

We hypothesize continuous adductor canal block with steroid adjuvant would offer no inferior analgesics and rehabilitation ability than continuous femoral nerve block for postoperative patients receiving total knee arthroplasty.

A total of 80 patients who will undergo total knee arthroplasty will be randomized into two groups:

Treatment groups Treatment details Femoral Group (40 patients) Continuous femoral nerve block (bolus: 0.5% Ropivacaine 10-15 ml ; infusion of 0.15 % Ropivacaine 4-6ml/h) Adductor Group (40 patients) Adductor canal block with steroid adjuvant (bolus: 0.5% Ropivacaine 10-15ml; Dexamethasone 4mg) (Total 80 patients will be recruited)

• All patients will receive single shot tibial nerve block with local anaesthetics (0.5% Ropivacaine 5-8ml) before surgery for analgesia of posterior knee.
• All patients will receive the same preemptive and postoperative multimodal medications for perioperative analgesia.
• All groups will receive standardized method of spinal anaesthesia and standardized method of intraoperative sedation for the surgery.
• Intravenous patient controlled analgesia (PCA) with morphine will be given for 48h to patient as rescue analgesia.

Inclusion Criteria:

• Diagnosis of primary osteoarthritis
• Scheduled for elective total knee arthroplasty
• Signed written informed consent
• Planned use of spinal anaesthesia
• Cognitive sound to use assessment tools

Exclusion Criteria:

• Patients refusing to give consents
• Scheduled for revision total knee replacement
• Patient outside range of 30 to 80 yrs old
• Non-chinese population
• Cognitive impairment/ inability to use the outcome assessment tools
• Contraindications to regional anesthesia
• severe cardiovascular disease (unstable angina, second or third degree heart block)
• pre-existing neurologic disease including psychiatric disorder
• drug abuser
• Pre-operative history of neurological abnormality in the ipsilateral leg e.g. history of stroke, neurogenic pain or previous nerve injury.
• Allergy or contraindication to drugs used in this study: morphine, Non-steroidal anti-inflammatory drugs (NSAID) such as ketorolac , diclofenac, dihydrocodeine, local anaesthetics (lignocaine, ropivacaine, bupivacaine), epinephrine
• Moderate or severe renal impairment (serum creatinine > 160 micromol/l)