Genicular Blocks in the Emergency Department: A Retrospective Review of Early Experience

Knee pain is a common cause of emergency department (ED) presentations. Often, this is due to acute on chronic knee osteoarthritis, which requires both acute pain control in the ED and sustained analgesia to promote return of functional mobility. Ultrasound guided genicular nerve blocks (GNB) have emerged from the anesthesia literature, initially as a method of motor sparing analgesia for knee arthroplasty, with more recent evidence supporting its use in chronic knee osteoarthritis. The objective of this study is to evaluate the efficacy of the GNB for acute pain control in the ED.

This is a retrospective multicenter observational study of all adult ED patients that underwent GNB between September 2023 and August 2025. The primary outcome was the reduction in pain scores on a 10 point numerical rating scale (NRS) following GNB. Secondary outcomes include ED disposition, ED return and hospital readmissions within 30 days, and ED and prescription opioid use. Safety outcomes included unexpected motor blockade, septic arthritis, injection site infection, and local anesthetic toxicity.

A total of 1203 ED nerve block procedures were identified across three hospitals. Of those, there were 49 patients that received GNB, with nine of them receiving bilateral blocks. One patient was excluded because they were an admitted patient boarding in the ED for multiple days. The mean reduction in pain on a NRS was 6.43 (95% confidence interval 3.83-9.04) between pre- and post-block pain scores. Sixteen patients arrived via ambulance, but only five patients ultimately required admission (two of those were admitted for reasons unrelated to knee pain). Seven patients had ED return visits for ipsilateral knee pain within 30 days, but no adverse events were noted on structured chart review.

This observational study of genicular nerve blocks in the emergency department demonstrates a substantial immediate reduction in pain, without any subsequent complications. While the strength of the results is limited due to lack of a control group and absence of longer term outcome data, the GNB is a promising intervention that should be further evaluated in the ED.