CONTEXT: Anterior cruciate ligament (ACL) reconstruction surgery is associated with moderate to severe postoperative pain, which may be ameliorated by peripheral nerve blocks. The adductor canal block (ACB) is an almost exclusively sensory nerve block that has been demonstrated to reduce pain and opioid consumption after major knee surgery. OBJECTIVES: To investigate the analgesic effect of ACB in patients receiving a basic analgesic regimen of paracetamol and ibuprofen after arthroscopic ACL reconstruction under general anaesthesia. DESIGN: Randomised, double-blind, placebo-controlled, parallel groups. SETTING: Day Case Surgery, University of Copenhagen, Glostrup Hospital, Denmark, June 2010 to March 2012. PATIENTS: Fifty patients, aged 18 to 70 years, scheduled for arthroscopic ACL reconstruction. INTERVENTIONS: Patients were randomised to receive ACB with either 30 ml ropivacaine 7.5mgml-1 (n=25) or 30 ml 0.9% saline (n=24). MAIN OUTCOME MEASURES: Primary outcome was pain score (0 to 100 mm) during standing at 2 h after surgery. Secondary outcomes were pain at rest, during standing and after walking 5 m, opioid consumption and opioid-related side effects for 24 h after surgery. RESULTS: Median (interquartile range) pain scores for the primary outcome were 20 (12 to 36)mm in the ropivacaine and 20 (10 to 44)mm in the control group (P=0.84, 95% confidence interval for difference of -9 to 12 mm). No significant differences were observed in any of the secondary outcomes. CONCLUSION: An analgesic regimen with paracetamol and ibuprofen provides acceptable postoperative pain control after arthroscopic ACL reconstruction. ACB did not confer further benefit in our patients.