BACKGROUND: Adductor canal blockade (ACB) has been demonstrated to be effective in the treatment of post-operative pain after major knee surgery. We hypothesised that the ACB would reduce pain and analgesic requirements after minor arthroscopic knee surgery.

METHODS: Seventy-two patients scheduled for minor knee surgery were enrolled in this placebo-controlled, blinded trial. The patients were randomised to receive an ACB with either 30 ml ropivacaine 7.5 mg/ml (n = 36) or saline (n = 35) in addition to a basic analgesic regimen with paracetamol and ibuprofen. Primary outcome measure was pain during standing at 2 h after surgery. Secondary outcomes were pain at rest, while standing and after a 5-m walk; opioid consumption and opioid-related side effects 0-24 h after surgery.

RESULTS: Pain scores {median [interquartile range (IQR)]}, regarding primary outcome were 15 (0-26) mm in the ropivacaine vs. 17 (5-28) mm in the control group, 95% confidence interval (CI) (-10 to 4) mm, P = 0.41. Ketobemidone consumption 0-2 h post-operatively [median (IQR)] was lower in the ropivacaine vs. the control group: 0.0 (0.0-2.5) mg vs. 2.5 (0.0-5.0) mg, 95% CI: -2.5 to 0 mg, P = 0.01. No differences were observed for any other outcome.

CONCLUSION: No significant analgesic effect of the ACB could be detected after minor arthroscopic knee surgery with a basic analgesic regimen with acetaminophen and ibuprofen, except from a minor reduction in immediate requirements for supplemental opioids. Clinicaltrials.gov Identifier: NCT01254825.