Adductor canal block versus local infiltration analgesia for postoperative pain after anterior cruciate ligament reconstruction: a single centre randomised controlled triple-blinded trial

Abstract

BackgroundBoth the adductor canal block (ACB) and local infiltration analgesia (LIA) are effective analgesic techniques after anterior cruciate ligament (ACL) reconstruction, but they have never been compared head-to-head. This randomised controlled triple-blinded trial tested the hypothesis that ACB provides superior analgesia to LIA after ACL reconstruction, with additional focus on postoperative functional outcomes. MethodsOf 104 enrolled ACL reconstruction patients receiving general anaesthesia, 52 were randomly allocated to either ACB under ultrasound guidance or LIA. For each intervention, ropivacaine 0.5%, 20 ml was injected. Postoperative pain treatment followed a predefined protocol with i.v. patient-controlled morphine, paracetamol, and ibuprofen. The primary outcome was cumulative i.v. morphine consumption at 24 h after operation. Secondary pain-related outcomes included resting and dynamic pain scores (numeric rating scale out of 10) measured 2, 24, and 48 h after operation and cumulative i.v. morphine consumption 2 and 48 h after operation. Early function-related outcomes evaluated were quadriceps strength, walking distance, and range of motion, all measured 24 and 48 h after operation. Late function-related outcomes were concentric quadriceps strength, single-hop test, triple-hop test, cross-over test, and Y balance test, measured at 4 and 8 postoperative months. ResultsCumulative i.v. morphine consumption at 24 h was similar between groups (ACB group: 17.1 mg [95% confidence interval, CI: 13.1, 21.2]; LIA group: 17.7 mg [95% CI: 13.2, 22.6], P=0.84). Similarly, no differences between groups were seen in the secondary pain- or function-related outcomes. ConclusionsACB and LIA result in equivalent postoperative opioid consumption with similar impact on postoperative pain scores and functional outcomes. Clinical trial registrationNCT 02524652.