LIA vs. LIA + ACB-iPACK Block for Total Knee Arthroplasty

LIA is the mainstay of postoperative analgesia in patients having knee arthroplasty. Performed by surgeons, LIA provides effective postoperative pain relief and reduces opioid requirements. Similar analgesic benefits have also been attributed to adductor canal and iPACK blocks, which partially block sensory innervation to the knee and its posterior capsule. Performed by anesthesiologist preoperatively, these blocks have also been incorporated into the care standard in numerous centers. However, it is not clear whether adding the adductor canal and iPACK blocks yields any incremental analgesic benefits. The investigators aimed to evaluate the benefits of adding adductor canal and iPACK blocks to LIA in patients having total knee arthroplasty.

Inclusion criteria

• ASA classification I-III
• BMI < 35 kg/m2
• Having elective unilateral total knee arthroplasty

Exclusion criteria

• Bilateral knee surgery.
• Pre-existing neurological deficit or peripheral neuropathy in the lower the lower limbs
• Severe, poorly controlled cardiac conditions, significant arrhythmias, severe valvular heart diseases
• Severe, poorly controlled respiratory conditions (severe COPD, severe interstitial lung disease, severe / poorly controlled asthma)
• Contraindication to regional anesthesia (e.g. bleeding diathesis, coagulopathy, sepsis, infection at the site of potential needle puncture on the posterior chest)
• Patient refusal
• Chronic pain disorder
• Chronic opioid use (≥30 mg oxycodone / day)
• Contraindication (or allergy) to a component of multi-modal analgesia protocol
• Allergy to amide local anesthetics used in nerve blocks
• Contraindications to spinal anesthesia
• Significant psychiatric disorder that would preclude objective study assessment
• Pregnancy
• Inability to provide informed consent