Why are we doing this study? People who have knee replacement surgery often feel pain afterward. Doctors use different methods to control this pain. One method is an injection of numbing medicine directly into the knee during surgery, called local infiltration analgesia (LIA). Another method uses a thin tube (catheter) placed near nerves in the leg to continuously deliver numbing medicine, called a nerve block. This study compares these two pain control methods after knee replacement surgery, to find out whether the injection method (LIA) works at least as well as the nerve block method for controlling pain.
Who can take part in this study? Adults aged 18 to 90 years who need a first-time (primary) knee replacement because of knee arthritis can take part. Participants must be able to walk before surgery, be in generally stable health, and be able to give informed consent. People with a knee injury (rather than arthritis), people who use a wheelchair, and people unable to give consent were not included.
What happens during this study? 78 participants were randomly assigned, like a coin flip, to receive either the injection into the knee (LIA) or the nerve block through a catheter for pain relief after surgery. Both groups also received the same standard pain medicines by mouth or vein as needed. Researchers measured pain levels using a 0-10 pain scale before surgery and at 24, 48, 72, and 96 hours afterward. They also measured knee movement (range of motion), how much extra pain medicine was needed, and how satisfied participants were with their pain control. The study took place at one hospital, the Elisabethinen Hospital in Klagenfurt, Austria, between June 2025 and January 2026.
Inclusion Criteria:
Exclusion Criteria:
Participants received intraoperative periarticular local infiltration analgesia consisting of 200 mL ropivacaine (2 mg/mL, first 50 mL discarded), 30 mg ketorolac, and 0.5 mg epinephrine, injected during total knee arthroplasty. All participants additionally received the standardized postoperative oral/intravenous analgesic regimen (diclofenac, hydromorphone, metamizole, paracetamol as needed).
Participants received continuous femoral and sciatic nerve block via perineural catheters. An initial local anesthetic bolus was followed by continuous ropivacaine 0.2% infusion for 48 hours postoperatively (5 mL/h for the first 24 hours, then reduced to 3 mL/h), with patient-controlled boluses available. The same standardized postoperative oral/intravenous analgesic regimen as the LIA group was administered.
Klagenfurt, Carinthia 9020, Austria
Peripheral Nerve Blocks vs Periarticular Local Anesthetic Injection for Total Knee Arthroplasty (TKA)
Local Infiltration Analgesia Versus Quadruple Nerve Blocks in Total Knee Arthroplasty.
Trial to Compare Femoral Nerve Block With Local Anaesthetic Injection for Post-operative Pain After Knee Replacement.
Combination of Nerve Blocks and Local Infiltration Analgesia in Knee Arthroplasty
The Efficacy of Local Infiltration Analgesia for Postoperative Pain Management After Total Knee Arthroplasty
Efficacy of Multimodal Peri- and Intraarticular Drug Injections in Total Knee Arthroplasty