Eight Sensory Nerve Blocks After Total Knee Arthroplasty — Less Opioid Use?

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Key finding: an extensive ultrasound-guided combination of eight sensory nerve blocks did not reduce pain after total knee arthroplasty compared with local infiltration analgesia. Lower opioid consumption and a shorter hospital stay were secondary findings, so they should be treated as signals for further research rather than proof that the entire protocol is superior.

Why is this study interesting?

Early mobilisation after total knee arthroplasty requires analgesia that controls pain while preserving muscle function as much as possible. This is why motor-sparing approaches such as adductor canal block, IPACK block and genicular nerve blocks have been developed. In a paper published electronically on 8 September 2026, the investigators asked whether a broader block of the knee’s sensory innervation could outperform local infiltration analgesia.

Question and methodology

The randomized trial included 217 patients undergoing total knee arthroplasty. The intervention group received an ultrasound-guided combination of eight sensory nerve blocks using 40 mL ropivacaine 5 mg/mL with 75 µg clonidine. In addition to the adductor canal, IPACK and genicular nerve blocks, the protocol also targeted nerves supplying the vastus medialis and vastus intermedius muscles and the anterior femoral cutaneous nerve.

The control group received local infiltration analgesia with 150 mL ropivacaine 2 mg/mL plus 0.5 mg epinephrine. The primary endpoint was resting pain intensity, assessed repeatedly from admission to the post-anaesthesia care unit until 2:00 p.m. on the first postoperative day. Secondary outcomes included opioid consumption expressed as oral morphine equivalents over 48 hours and length of hospital stay.

Results

There was no statistically significant difference in pain intensity between the groups at any of the prespecified time points. The trial therefore did not demonstrate superiority of the extensive block combination for its primary endpoint.

• Median 48-hour opioid consumption was 70 mg oral morphine equivalents after the nerve blocks and 96 mg after local infiltration analgesia; p = 0.008.
• Median length of stay was 1 day and 2 days, respectively; p < 0.001.
• Both findings were secondary and exploratory.

Clinical interpretation for an orthopaedic surgeon

No difference in pain combined with lower opioid use may appear encouraging: similar symptom control was achieved with less opioid exposure. However, the hierarchy of endpoints matters. The protocol was not superior for the primary outcome, and the differences in opioid consumption and length of stay require confirmation in a trial specifically designed around those outcomes.

The study also cannot identify which component of the combination produced the observed signal. Two complete and substantially different perioperative protocols were compared, rather than a single additional block. Total ropivacaine dose, the use of clonidine or epinephrine, mobilisation pathways and discharge criteria may all influence the results.

Limitations

• The primary endpoint was negative, while the favourable differences concerned secondary outcomes.
• The extensive procedure involves multiple needle placements and requires experience with ultrasound-guided nerve blocks.
• The study cannot isolate the effect of individual blocks or the contribution of clonidine.
• Length of stay depends not only on analgesia but also on local care pathways and discharge criteria.
• The abstract does not show whether the difference in opioid consumption translated into fewer episodes of nausea, delirium, falls or other clinical benefits.

What could this change in practice?

The study supports further work on analgesic strategies that reduce opioid exposure without worsening pain control or muscle function. At this stage, it argues more strongly for comparing and simplifying individual components of the protocol than for routinely implementing all eight blocks.

What does the study not prove?

It does not show that blocking eight sensory nerves provides better analgesia than local infiltration analgesia. It also does not show that the same effect would occur in a different perioperative pathway or that the shorter hospital stay was caused directly by the nerve-block protocol itself.

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Source

Fellert F, Sjövall F, Flivik G, Ekman A. A Novel Multiple Sensory Nerve Block Combination Using Ultrasound Guidance in Knee Arthroplasty: A Randomized Clinical Trial. A&A Practice. 2026;20(9):e02274. DOI: 10.1213/XAA.0000000000002274. PubMed.

Educational material for healthcare professionals. It does not constitute an individual therapeutic recommendation.

Content prepared by: Tomasz Poboży - orthopaedic surgeon.