- Design
- Randomised, triple-blind controlled trial
- Population
- 80 adults having ACL reconstruction with a femoral triangle block
- Primary outcome
- Cumulative intravenous morphine at 24 hours
- Effect
- Median 12 mg IPACK vs 16 mg tibial nerve block (P = 0.073)
A triple-blind randomised trial allocated 80 adults having anterior cruciate ligament reconstruction under general anaesthesia with a femoral triangle block to either IPACK (20 ml ropivacaine 0.2%) or a selective tibial nerve block (5 ml ropivacaine 0.75%) for posterior knee pain.
Median morphine use over 24 hours was 12 mg with IPACK and 16 mg with the tibial nerve block, a difference that was not significant. Pain scores, early function at 24 and 48 hours, and quadriceps strength and hop testing at four and eight months did not differ. No complications were reported.
The trial was designed to show IPACK was better and did not. Either block appears reasonable for posterior knee cover in this setting.
It is a single trial of 80 patients, so small differences cannot be excluded.
- Either IPACK or a selective tibial nerve block can cover posterior knee pain after ACL reconstruction.
- Choose the block your team performs most reliably.
- Both were combined with a femoral triangle block and multimodal analgesia here.
- Function at four and eight months did not differ.
Why it matters
It removes a reason to switch techniques for posterior knee analgesia.
The statistics, in plain English
A P value of 0.073 means the difference in morphine use could easily be chance. With 80 patients, the trial could miss a small real difference.
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