- Design
- Randomised, double-blind, superiority trial, single centre
- Population
- 60 adults having ACL reconstruction
- Primary outcome
- Average NRS pain over 48 hours
- Effect
- −0.31 points (95% CI −1.39 to 0.77), p = 0.58
In a single-centre, double-blind trial, 60 adults having ACL reconstruction were randomised to continuous femoral nerve block or continuous adductor canal block, each with 20 mL of 0.5% ropivacaine and a home infusion of 0.2% ropivacaine. 57 completed.
Average pain over 48 hours did not differ (−0.31 NRS points, 95% CI −1.39 to 0.77). Pain was lower with femoral block on the day of surgery. In an exploratory analysis, fewer femoral patients needed more than 50 morphine milligram equivalents (5/28 vs 13/29). Quality of recovery and continuous passive motion compliance did not differ.
The motor-sparing adductor canal block gave similar overall analgesia. The opioid signal with femoral block is exploratory and must be weighed against quadriceps weakness and fall risk.
- Adductor canal block remains a reasonable default for ACL reconstruction.
- Warn patients about quadriceps weakness if a femoral catheter is used.
- Provide crutches and fall precautions with any continuous knee block at home.
- Review opioid use on day 1 and escalate multimodal analgesia as needed.
Why it matters
It confirms that motor-sparing analgesia does not trade away overall pain control after ACL surgery.
Don't overread it
The fewer high-opioid users with femoral block came from an exploratory analysis in 57 patients.
The statistics, in plain English
A 0.31-point difference on a 0–10 scale is not clinically meaningful, and the interval rules out a difference much above one point. The trial was small, so rarer harms such as falls cannot be compared.
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