Dr. Matt Schmitz discusses 2 new RCTs investigating regional blocks in total knee and hip arthroplasty.
The use of regional blocks in orthopaedic surgery has surged as we focus on multimodal pain control for our patients to enhance their recovery and experience. In the April 16, 2025 issue of JBJS, 2 double-blinded randomized controlled trials (RCTs) examine the effect of regional blocks on patient outcomes in the immediate postoperative period.
Wang et al. evaluated the efficacy of administering an adductor canal block (ACB) 30 minutes before general anesthesia versus postoperatively in the recovery room in 100 patients undergoing primary total knee arthroplasty (TKA) at their institution in the People’s Republic of China. The primary outcome was postoperative morphine consumption, while secondary outcomes included pain levels, stress responses, functional recovery, incidence of chronic pain, and complications. The study is available at JBJS.org:
Patients receiving the preoperative ACB had significantly lower morphine consumption within the first 24 hours and throughout hospitalization, a longer time until the first rescue analgesia, and lower intraoperative opioid consumption and inhaled anesthetic use. Additionally, preoperative ACB was associated with lower serum cortisol and adrenocorticotropic hormone levels on the morning of postoperative day 1, lower pain scores within 12 hours postoperatively, better knee motion on postoperative day 1, and a lower incidence of chronic pain at 3 months postoperatively. No significant differences between the 2 groups in ambulation distance, hospital length of stay, or complication rates were observed. Interestingly, while not a significant difference, the average time from the end of surgery to discharge was 57.8 ± 14.3 hours in the preoperative ACB group and 59.5 ± 12.8 hours in the postoperative ACB group.
The authors concluded that administering an ACB before TKA may enhance pain relief and reduce opioid consumption during hospitalization, lower intraoperative and postoperative stress responses, and reduce the incidence of chronic pain at 3 months, suggesting potential longer-term benefit from early pain relief.
In the second study, Hanauer et al. investigated the efficacy of the pericapsular nerve group (PENG) block in reducing postoperative pain and opioid consumption as well as length of stay in patients undergoing elective primary anterior total hip arthroplasty (THA). Conducted at Fribourg Cantonal Hospital in Switzerland, this RCT included 60 patients, with 32 receiving the PENG block and 28 receiving a placebo. Access the study:
Outcomes measured included postoperative pain on a visual analogue scale (VAS) at various intervals, total morphine consumption within the first 24 hours, and hospital length of stay. The authors found no significant differences between the 2 groups in pain scores or morphine consumption. However, the median length of stay was significantly shorter in the PENG group compared to the placebo group (2 versus 4 days; p = 0.003). Additionally, all patients in the PENG group were discharged to home, while some in the placebo group were discharged to a rehabilitation facility.
While the PENG block did not significantly reduce pain or opioid use, it was associated with a notable decrease in length of stay, which may suggest its potential benefit in improving postoperative recovery following elective primary anterior THA.
As surgeons, we continue to strive to improve the patient experience—decreasing postoperative pain and reducing the length of hospital stays and costs, without sacrificing outcomes. Both of these high-quality, level-I studies show the potential promise of the use of regional blocks. I commend the authors and look forward to further investigations on the use of regional anesthesia in arthroplasty procedures, with our patients in mind.
Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media
Figure reproduced from: Hanauer M, Heimann AF, Kricka P, Blümel S, Marti D, Moosmann AM, Popa V, Zurmühle CA, Schwab JM, Tannast M. The PENG Block in Elective Primary Anterior Total Hip Arthroplasty Is Associated with Reduced Length of Stay: A Multidisciplinary Prospective Randomized Double-Blinded Controlled Trial. J Bone Joint Surg Am. 2025 Feb 28. Epub ahead of print. Copyright © 2025 The Authors. This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND).
