My husband is having a total knee replacement today. As I was saying goodbye to him at the hospital, the anesthesiologist was telling him they would use a nerve block with the anesthesia. This is to reduce pain after the operation. There was no time to ask any questions. What is it and what does it do?

Messages from the muscles to the nerves can be blocked with a drug injected into the nerve. The drug works like Novocain and numbs the area. Sensation and motor function are stopped for that nerve up to 16 hours. For a nerve block with total knee replacement, the patient can expect numbness along the front and inner aspect of the thigh.

By reducing pain, the numbing agent prevents spasm of the leg caused by the pain after surgery. Studies show a nerve block is also narcotic-sparing. This means the patient needs and uses much less pain medication during the first 24-hours after surgery.

Overall nerve block before joint replacement is a simple and safe way to control post-operative pain.