Ultrasound Guided Genicular Nerve Blocks for Pain Management Following Total Knee Replacement: A Narrative Review.

Purpose of review: Total knee replacement (TKR) is a common procedure to alleviate pain in patients with severe osteoarthritis of the knee after failed conservative treatment. While generally safe, postoperative pain is a significant issue many patients experience following surgery.

Recent findings: To control postoperative pain, numerous treatments may be administered which may be given preoperatively, intraoperatively, or postoperatively. These treatments include medications such as nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen, and opioids. Additionally, peripheral nerve blocks (PNB) may be performed prior to total knee replacement to limit pain after the surgery. A specific type of PNB done prior to total knee replacement is the genicular nerve block (GNB) which targets five genicular nerves that innervate different parts of the knee joint. This type of block is designed to prevent pain impulses from being sent to the central nervous system from the knee without affecting movement of the lower extremity by sparing efferent nerves innervating muscles. PubMed was used to identify the studies found in this review that are less than 5 years old using the search term "genicular nerve block clinical studies." Most studies compared GNB alone compared to other blocks, however some used GNB in combination with other blocks, most at a maximum of 48 h postoperative. GNB is typically performed by anesthesiologists under ultrasound guidance to ensure accurate placement of the block. Clinical studies have shown that GNB is effective in controlling pain following TKR leading to lower pain scores following surgery as well as a reduced level of opioid consumption. Additionally, GNB has shown reduced motor weakness following TKR compared to other types of PNBs allowing earlier mobilization of patients. However, more studies are needed to further investigate the efficacy of GNB compared to other PNBs to treat postoperative pain following TKR.