While general anesthesia is a safe option, both hip and knee replacements are performed preferably under regional anesthesia. Choices for regional anesthesia include spinal anesthesia, epidural anesthesia, or one of a variety of peripheral nerve blocks. Many surgeons and anesthesiologists prefer regional anesthesia because data shows it can reduce complications and improve your recovery experience with less pain, less nausea, less narcotic medicine required, etc.
Recently, peripheral nerve blocks have become more popular as an adjunct for pain control. For total knee replacement, this can include an adductor canal block, which allows pain control without causing weakness of your muscles.
Discussion regarding anesthesia should be there between anesthetists and patients as a lot of them have to fear needles going in their back and some believe it will cause back pain later too. Post-operative pain management protocol should be discussed with the surgeon and anesthesia team prior to surgery.
If you have a general anesthetic instead, you may also be given a nerve block – this will block pain in your leg for up to 36 hours after surgery but will also weaken the leg temporarily.
Many surgeons instead inject a type of local anesthetic into the tissues around the knee during the operation to numb the pain but still allow the muscles to work so you can get up sooner after the operation.