What Is Knee Replacement Surgery?

Knee replacement surgery can help you get back to the activities you enjoy.

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If you are preparing for knee replacement surgery, you’re in good company: It’s one of the most common orthopedic surgeries. U.S. surgeons perform almost 300,000 knee replacement surgeries every year, according to the American Academy of Orthopedic Surgeons.

Why Get Knee Replacement Surgery?

Your knees bear a lot of your weight and help you perform many daily activities. When you have severe and chronic knee pain, it can really limit your mobility and impact your quality of life.

“It really does debilitate patients when they're unable to participate in activities that their family [is] doing, or go on vacations and stuff because of the pain that they have associated with their joint,” says Ann Marie Moynihan, RN, director of nursing at NYU Langone Health.

Additionally, knee pain may progress to further problems. For example, you may develop “bad habits” to take some of the pressure off your knees, such as changing your posture or gait. These may help temporarily, but can cause additional pain or problems elsewhere in your body.

“Oftentimes, it'll go to a point where their entire lower limb or the entire leg has taken on either a bow-legged or a knock-kneed alignment, which is quite severe and [makes] it extremely difficult to walk,” says William Macaulay, MD, orthopedic surgeon at NYU Langone Health.

What Is Knee Replacement Surgery?

“Knee replacement surgery is when we replace a patient's damaged joint, remove their cartilage, and replace that with a manmade joint, usually metal or plastic,” says Dr. Macaulay.

In a healthy knee, there are several components that work together to create smooth and pain-free movements. Cartilage provides flexible connective tissue lining the bones of the leg—femur, tibia, and patella (knee cap)—to reduce friction. The meniscus provides cushion between the bones to absorb shock and provide stability.

A knee replacement is less about the bone itself and more about damaged cartilage, which have sensitive nerve endings. “The knee replacement typically will reduce a patient's pain by getting rid of the damaged cartilage and thereby removing the very irritated nerve endings,” says Dr. Macaulay.

Recovery After Surgery

“A patient that was very mobile before [a] joint replacement can be still very active again. It all depends on the individual pain and the mobility of the patient themselves,” says Moynihan.

Immediately following knee replacement surgery, you’ll likely be in the hospital for two to three days. During this time, you will work on moving and walking again. You might go home even earlier: Dr. Macaulay says at least a fifth of his patients have outpatient surgery and go home the same day, but that is subject to your surgeon and your individual health. You will also work with a physical therapist, both right after the surgery and in the weeks or months that follow.

“It's a long recovery process, but the vast majority of patients will feel better within three to four weeks after their joint is replaced,” says Dr. Macaulay. Learn more about what to expect during recovery from joint replacement surgery here.

A Better Life

The recovery process may be long and difficult, but the end results are often worth it. “A knee replacement surgery can improve a patient's quality of life by allowing them the ability to move more without having increased pain,” says Moynihan. That can help you to get back to the activities you used to enjoy.