Eighty patients undergoing total knee arthroplasty for knee osteoarthritis were randomized to receive either a femoral triangle block with an interspace between the popliteal artery and the capsule of the posterior knee (IPACK) block (n=40) or a local periarticular injection (PAI; n=40). The primary outcomes of interest included pain at rest and during active exercise on a Visual Analog Scale for 72 hours post-operation. Secondary outcomes included quadriceps muscle strength, range of motion, systolic and diastolic blood pressure, heart rate, length of stay, morphine consumption, propofol use, and the incidence of adverse events after 3 days. Pain at rest and with movement were significantly lower in the IPACK at all time points except for pain at rest at 24 hours. Similarly, quadriceps muscle strength was also significantly better at all times in the IPACK group vs. PAI.