TOPLINE

Among patients undergoing reconstruction of the anterior cruciate ligament (ACL) under general anesthesia with a femoral triangle block, infiltration between the popliteal artery and the capsule of the knee (IPACK) provided postoperative analgesia comparable to that of a selective tibial nerve block.

METHODOLOGY

• Researchers conducted a randomized controlled trial at a hospital in Switzerland to assess whether IPACK was superior to a selective tibial nerve block for analgesia following reconstruction of the ACL.
• They included 80 adult patients from May 2022 to November 2024 who had an American Society of Anesthesiologists physical status of 1-3 and were undergoing planned primary reconstruction of the ACL utilizing a hamstring autograft combined with lateral tenodesis; of these, 76 completed the study protocol.
• Participants were randomly allocated to one of two interventions: IPACK using 20 mL ropivacaine 0.2% (n = 39) or a selective tibial nerve block using 5 mL ropivacaine 0.75% (n = 37), both performed under ultrasound guidance, in addition to a femoral triangle block with 20 mL ropivacaine 0.75% performed before surgery.
• All procedures were performed under general anesthesia, and postoperative analgesia comprised 1 g paracetamol given every 6 hours, 400 mg ibuprofen given every 8 hours, and patient-controlled intravenous (IV) morphine analgesia delivering 2-mg boluses every 10 minutes.
• The primary outcome was the consumption of IV morphine within 24 hours after surgery. Secondary outcomes were pain-related outcomes assessed at 2, 24, and 48 hours; early functional outcomes assessed at 24 and 48 hours; and late functional outcomes measured at 4 and 8 months.

TAKEAWAY

• At 24 hours after surgery, the median cumulative use of IV morphine was 12 mg in the IPACK group vs 16 mg in the selective tibial nerve block group (P = .073).
• Pain scores during rest and activity showed no significant differences between the two groups at 2, 24, or 48 hours following surgery.
• Early functional outcomes, such as passive range of motion, strength of the quadriceps muscle, and walking distance, were comparable between the two groups. Late functional outcomes, including concentric strength of the quadriceps, single-hop test, agility test, and additional measures, also did not differ significantly between the two groups.
• The study recorded no hematoma, persistent paresthesia or paresis, infection, or neuropathic pain.

IN PRACTICE

"With two viable methods for delivering posterior knee analgesia after ACL reconstruction, clinicians may choose the technique that best aligns with their clinical environment," the researchers wrote. "[B]oth techniques offer comparable pain control and can be considered based on individual practice preferences," they concluded.

SOURCE

The study was led by Ludovic Beun of the Department of Anaesthesia at the Lausanne University Hospital in Lausanne, Switzerland. It was published online on October 6 in Anaesthesia.

LIMITATIONS

The quality of the nerve blocks was not assessed to preserve blinding, so absolute clinical effectiveness of all blocks cannot be confirmed. Patients were hospitalized for 24-48 hours postoperatively, which differs from ambulatory practice settings common in many centers.

DISCLOSURES

The study was supported by the European Society of Regional Anaesthesia and Pain Therapy and the Foundation Anna et André Livio Glauser. One author reported receiving grants from the Swiss Academy for Anaesthesia Research and the Swiss National Science Foundation to support clinical research and being an associate editor of Anaesthesia.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.