Ninety-two patients undergoing unilateral total knee arthroplasty were randomized to receive an interspace between the popliteal artery and capsule of the posterior knee (IPACK) block (n=46) or no IPACK block (n=46) as part of a comprehensive enhanced recovery after surgery (ERAS) protocol that included a primary spinal anesthetic, adductor canal block (ACB), and periarticular joint infiltration (PAI). The primary outcome was total postoperative opioid consumption within the first 24 hours. Secondary outcomes included pain scores at various postoperative intervals, PACU length of stay, time to first opioid use, incidence of posterior knee pain, ambulation distance on postoperative day 1, and hospital length of stay. Overall, the study found no significant differences in total opioid use or most secondary outcomes between groups. However, the IPACK group had significantly lower incidence of posterior knee pain. The study suggests that although the IPACK block did not reduce opioid consumption, it may be useful for addressing posterior knee pain in this ERAS setting.