Optimal Analgesic Volume for Popliteal Plexus Block After Total Knee Arthroplasty: A Blinded RCT Protocol

Abstract

Background: Adjunct treatment with a popliteal plexus block (PPB) provides moderate enhancement to multimodal analgesic regimens following total knee arthroplasty while maintaining motor function. However, the optimal anesthetic volume of local anesthetic for PPB remains unknown. Aim: To compare the analgesic effects of PPB with 10 versus 20 mL of local anesthetics as an adjunct to a femoral triangle block after total knee arthroplasty. Methods: This blinded, controlled, randomized clinical trial will include 120 patients, randomly assigned to receive PPB with either 10 or 20 mL of bupivacaine 5 mg/mL. All patients undergo primary total knee arthroplasty under spinal anesthesia and receive a multimodal analgesia regimen, including paracetamol, ibuprofen, opioids, dexamethasone, and a femoral triangle block. Outcomes: Primary outcome is 24-h postoperative opioid consumption. Secondary outcomes include the frequency of patients with opioid-free analgesia in the first 24 h after surgery, postoperative pain intensity at rest and during mobilization, postoperative muscle function of the leg, ability to mobilize with crutches 6 h after surgery, and Quality of Recovery-15 survey at 24 h after surgery. Conclusion: This trial hopes to optimize postoperative pain management after total knee arthroplasty by providing valuable insights into the optimal analgesic volume for PPB. Trial Registration: Danish Data Protection Agency: 693807, clinicaltrials.gov: NCT06908837, CTIS: 2024-520204-26-00.