Physician-authored summaries and commentary on the most important medical research, provided by the NEJM Group, a division of the Massachusetts Medical Society.
© Massachusetts Medical SocietyApril 2023
This procedure provided short-term pain relief that diminished gradually over 12 weeks.
Given the potential adverse effects of many oral analgesics, patients with painful knee osteoarthritis (OA) often require other interventions. One option, provided at some pain treatment centres, is radiofrequency ablation of the genicular nerves innervating the knee (NEJM JW Gen Med Nov 1 2020 and J Bone Joint Surg 2020; 102: 1501-1510); to predict whether this procedure is likely to help, it often is preceded by genicular nerve block with short-acting anaesthetic. Another option, examined in this Australian randomised trial, is genicular nerve block as the sole procedure – using both corticosteroid and anaesthetic.
A total of 59 patients with painful knee OA underwent ultrasound-guided genicular nerve block (with the corticosteroid betamethasone plus the anaesthetic bupivacaine) or a placebo procedure (with saline). At two and four weeks, mean reductions in pain were significantly greater with active treatment than with placebo – by two points on a 10-point scale. At eight weeks, the difference remained statistically significant but had decreased to one point; at 12 weeks, a smaller difference was no longer significant. Several other measures of pain and function paralleled the pain-scale findings. No adverse events were reported.
Comment: Genicular nerve block might have a role for patients in whom other pharmacological remedies are contraindicated or ineffective and who wish to avoid knee replacement. However, the pain relief is relatively short term, and we do not have data on the safety and efficacy of repeating the procedure at several-month intervals.
Allan S. Brett, MD
Clinical Professor of Medicine, University of Colorado School of Medicine, Aurora, USA.
Shanahan EM, et al. Genicular nerve block for pain management in patients with knee osteoarthritis: a randomized placebo-controlled trial. Arthritis Rheumatol 2023; 75: 201-209.
This summary is taken from the following Journal Watch titles: General Medicine, Ambulatory Medicine