When knee problems cannot be resolved with other treatment methods, knee replacement surgery is performed. In this procedure, the damaged or worn surfaces of the three bones that form the knee joint are replaced with an artificial joint made of metal and polyethylene. Modern knee prostheses can last 20–25 years, and with advancing technology, this lifespan is expected to increase further.

The surgery typically takes 45 to 90 minutes to complete. Both knees can be operated on during the same session. Most patients are able to walk without support by the end of the third week after surgery, and usually return to daily activities completely unaided within about one month.

Knee replacement surgery can be safely performed, especially in patients over the age of 65. For those between 55 and 65 years, however, alternative treatment methods are often considered first.