Intolerable pain or disability can signal that it’s time to consider a knee replacement.
Knee replacements can restore your mobility, but you don’t want to get one too soon—or wait too long.
If arthritis in your knee is keeping you from doing everything you want, whether that’s walking the dog or playing a game of tennis, you may be considering a knee replacement. If so, you have lots of company. An estimated 720,000 people undergo one annually, and almost 5% of women over 50 are sporting prosthetic knees. A knee replacement may seem like the ideal solution for restoring your mobility and preserving your independence. But when should you have one?
“There is no correct time. It depends on how much pain and disability you’re willing to tolerate before having surgery,” says Dr. Jeffrey Katz, professor of orthopedic surgery at Harvard Medical School. To determine the right time to have surgery, you’ll want to balance the benefits and risks of the procedure against your level of pain and disability.
You’ll also want to have tried other measures to reduce pain and strengthen your knee, such as switching to low-impact activities like swimming and cycling, undergoing physical therapy, and losing a few pounds if you are overweight.
What is involved in knee replacement?
Knee replacement is a major operation performed under general anesthesia. Although techniques vary, they usually involve removing the ends of the femur (thighbone) and tibia (shin bone), displacing the patella (kneecap), and disrupting muscles. The artificial knee joint is attached to the femur and tibia.
Although you’ll be in the hospital for only a few days, it may take several months to make a full recovery. You’ll also need physical therapy during the first couple of weeks, in which you’ll learn exercises to strengthen your knee and to bend and straighten it easily. You should be committed to doing the exercises several times a day.
What can you expect from a knee replacement?
It’s important to have realistic expectations for knee replacement surgery. A knee replacement won’t give you the powers of the bionic woman, but it should provide the following:
Pain relief. More than 80% of people who have knee replacements report a significant reduction in their level of pain.
Greater mobility. You should be able to do all the things you need to do for a normal life—walking, climbing stairs, and driving. You should also be able to undertake low-impact activities like swimming, cycling, golfing, and ballroom dancing. Some people are even able to resume running or singles tennis, although such high-impact activities can accelerate the wear on a new knee.
Increased flexibility. You should be able to bend and straighten your leg, and even kneel, but you may not have a greater range of motion than you did before surgery.
Many years of service. The failure rate for knee prostheses is around 0.5% per year. The likelihood of needing a second replacement before 15 or 20 years is about 10%.
What are the risks?
Although serious complications occur in fewer than 2% of people who undergo knee replacement, the risks are higher for older people and those who are obese. They include
blood clots in the leg veins—the most common complication of knee replacement surgery—which can be life-threatening if a clot breaks free and travels to your lungs
infection of the tissue around the replacement, which may occur either during your hospital stay or while you are recovering
complications from general anesthesia, rare events that can range from such problems as temporary confusion and memory loss to heart attack, stroke, or death.
When is the right time for you?
The ideal window of opportunity is different for everyone, Dr. Katz says. It depends on how much pain you’re in, how much your activity is curtailed, and how long you can expect the new knee to last. The choice is very personal. If you have a knee replacement in your 50s, you will likely need a second one when you’re older and possibly in poorer health. Some people delay their knee replacement to reduce this risk, but if you put it off too long, your thigh muscles can grow weak, which can make it harder to recover. Plus, chronic illnesses that you develop as you age can increase the risk of surgical complications.