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Background and Aims Patients undergoing elective Total Knee Arthroplasty (TKA) often experience significant postoperative pain, hindering early mobilisation and rehabilitation. Motor-sparing regional analgesia techniques, such as the Infiltration between Popliteal Artery and Capsule of the Knee (IPACK) block, aim to reduce pain, opioid use, and muscle weakness. However, the analgesic efficacy of the IPACK block remains unclear. This study investigates whether Adductor Canal Block (ACB) with IPACK reduces postoperative opioid consumption at 24 and 48 hours post-TKA compared to ACB with local infiltration of anaesthetic (LIA).

Methods This retrospective cohort study analysed 130 elective TKA cases at a regional NSW hospital over one year that received ACB + IPACK (n=71, 54.6%) and ACB + LIA (n=59, 45.4%). Linear regression analysis was then used to determine postoperative mean oral morphine equivalent daily dosage (OMEDD) at 24 and 48 hours, adjusting for age, sex, chronic opioid use, neuraxial anaesthesia, peripheral nerve infusion, and adjuvant analgesia.

Results This study demonstrated significant reductions in mean OMEDD at 24 hours with IPACK + ACB compared to ACB + LIA (IPACK + ACB: Mean OMEDD=54.8 mg; ACB + LIA: Mean OMEDD=76.4 mg, p=0.02). At 48 hours, no clinically or statistically significant reduction in OMEDD was observed.

Conclusions This study found that the addition of the IPACK block to ACB provides superior analgesia in the first 24 hours post-TKA when compared with ACB and LIA. These results support incorporating the IPACK block into standard care to reduce opioid consumption and associated adverse effects.