1. 2022;25;E489-E502Ultrasound-guided Genicular Nerve Blockade With Pharmacological Agents for Chronic Knee Osteoarthritis: A Systematic Review
   Systematic Review
   Tze Chao Wee, MBBS, Edmund Jin Rui Neo, MBBS, MMed, and Yeow Leng Tan, MBBS, MRCP.

BACKGROUND: Ultrasound-guided (ULSD-g) genicular nerve blocks (GNB) using pharmacological agents for pain control in chronic knee osteoarthritis (OA) are gaining in popularity. There lacks a systematic review to evaluate the ULSD techniques and pharmacological agents used during the intervention, and to assess the knee’s function postintervention.

OBJECTIVES: Our study aimed to determine the clinical characteristics of patients with chronic knee OA selected for ULSD-g GNB, describe the various ULSD-g techniques and pharmacological agents used to target the genicular nerves, and evaluate the primary outcomes of pain and function.

STUDY DESIGN: Systematic review.

METHODS: We looked at patients with chronic knee OA with symptoms or disease features of at least 3 months and the use of ULSD guidance for GNB using either local anesthetic agents and/or corticosteroids or alcohol. Two major electronic databases (Medline/PubMed and EMBASE) were searched from their inception through August 2021, without language restriction.

After removing duplicates, 2 reviewers independently reviewed the abstracts of 340 records. Nine of the 10 full texts that were reviewed were selected for inclusion. A third reviewer was involved in resolving disagreements.

Two reviewers extracted relevant information pertaining to study types, patient characteristics, intervention details, outcome measures, and adverse effects. This was followed by independent verification for accuracy.

RESULTS: Data synthesis: Nine studies were included with a total of 280 patients who had symptoms or disease features of at least 3 months. The National Institute of Health’s Study Quality Assessment Tools were used for quality appraisal, of which 8 studies were at least of fair quality. All studies involved targeted at least the superior medial, superior lateral, and inferior medial genicular nerves. ULSD techniques relied on bony, soft tissue, or periarterial landmarks; either local anesthetic agents and/or corticosteroids or alcohol were used in the injections. Follow-up intervals for pain and functional assessments were heterogeneous, ranging from one week to 6 months postprocedure. Sustained improvements in both pain and knee function were observed for up to 6 months regardless of the choice of pharmacological agents. Minimal adverse effects were reported.

LIMITATIONS: Meta-analysis was not performed due to heterogeneity of study designs, ULSD techniques, pharmacological agents used, and dosages administered. Only one study targeted additional genicular nerves; conclusions regarding the therapeutic blockade of these nerves could not be made.

CONCLUSIONS: There is fair evidence to at least target the superior medial genicular nerve, inferior medial genicular nerve, and superior lateral genicular nerve using local anesthetics, corticosteroids, or alcohol to reduce pain and to improve knee function in patients with chronic knee OA under ULSD guidance. The procedure is safe but more research is needed to determine the optimal interventional approach.

KEY WORDS: Ultrasonography, genicular nerve block, neurolysis, knee osteoarthritis