Adductor canal block (ACB) is a peripheral nerve blockade technique that provides good pain control in patients undergoing total knee arthroplasty (TKA) which however does not relieve posterior knee pain. The recent technique of an ultrasound-guided local anesthetic infiltration of the interspace between popliteal artery and the capsule of posterior knee (IPACK) has shown promising results in providing significant posterior knee analgesia without affecting the motor nerves. The hypothesis was that the combination of ACB + IPACK will provide better pain relief and improve knee function in the immediate postoperative period compared to ACB alone.

This is a prospective, randomized and double blinded study

All patients received :

• Pregabalin 150 mg preoperatively 12 h before the surgery.
• Single-shot spinal anesthesia with 10 to 12 mg of bupivacaine 0.5% and 2.5ug sufentanil patients were randomly allocated to receive:
• Group 1: IPACK + ACB single shoot
• Group 2: contineous ACB For group 1: IPACK was realized after spinal anesthesia with 40 ml ropivacaine 0.2% All patients received ACB in the immediate postoperative period with 20 ml ropivacaine 0.2%

Post operative analgesia included:

• Paracetamol 1g IV every 6 hours

• Diclofenac sodium (50mg) 1 tablet x 2 per day

• Pregabalin 150 mg given orally once daily for a period of 4 weeks.

• PCA morphine (Patient Controlled Analgesia), as a rescue analgesia,

• Continuous ACB catheter for 48H with :

  4 ml per hour 0.2% ropivacaine in group 2 4 ml per hour saline in group 1

Inclusion Criteria:

• primary total knee arthroplasty under spinal anesthesia

Exclusion Criteria:

• Contraindication or refusal to regional anesthesia
• Contraindication to non steroidal anti inflammatory (NSAID's)
• Allergy to opioids
• Allergy to paracetamol
• Creatinine clearance < 30ml/min
• Weight<50 kg or >100kg