Increased volume of local anesthetic may not improve outcomes for Popliteal Plexus Block After TKA: Study
Researchers have found in a new study that, among patients undergoing total knee arthroplasty, using 10 mL of local anesthetic for a popliteal plexus block is sufficient. Increasing the volume to 20 mL does not provide additional benefits in terms of pain relief or early functional recovery. The study was published in the Regional Anesthesia & Pain Medicine journal by Johan KS and colleagues.
Effective postoperative pain control is a key concern after total knee replacement surgery, and regional anesthetic techniques such as the popliteal plexus block have been explored for their effectiveness in postoperative pain control. However, the volume of anesthetic agent used in different studies varies, and this is a concern for anesthesiologists regarding the effectiveness of the anesthetic agent. This study is a randomized clinical trial that compares the effectiveness of 10 mL and 20 mL of anesthetic agents.
This blinded, randomized controlled trial consisted of 120 adult patients undergoing a primary unilateral total knee arthroplasty procedure under spinal anesthesia. The patients were divided equally to receive a popliteal plexus block with 10 mL or 20 mL of 5 mg/mL bupivacaine. All patients also underwent a femoral triangle block as part of a multimodal analgesic regimen, ensuring consistency in pain management for both groups.
Key findings:
A total of 120 patients were randomized to receive either 10 mL or 20 mL of bupivacaine.
Median 24-hour opioid consumption was identical in both groups at 15 mg (IQR 3.75–30 vs 0–30).
The median difference in opioid use was 0 mg (95% CI −10 to 5; p = 0.6).
No significant differences were observed in the proportion of patients achieving opioid-free analgesia.
Pain scores at rest and during ambulation were comparable between groups.
No differences were found in early functional outcomes, including ambulation with crutches.
Motor impairment and Quality of Recovery-15 scores were similar across both groups.
A 10 mL popliteal plexus block provides equivalent analgesia and functional outcomes compared with 20 mL after total knee arthroplasty, supporting the use of lower anesthetic volumes to enhance safety without compromising efficacy.
Reference:
Sørensen, J. K., Jensen, M. S. H., Grevstad, U., Nikolajsen, L., & Runge, C. (2026). Analgesic efficacy and functional outcomes of 10 versus 20 mL bupivacaine for popliteal plexus block after total knee arthroplasty: a randomized clinical trial. Regional anesthesia and pain medicine, rapm-2026-107696. Advance online publication. https://doi.org/10.1136/rapm-2026-107696
