When is it time for knee replacement?

When is it time for knee replacement?

Q: I have osteoarthritis. My right knee is especially painful and stiff. How do I know when the time is right for knee replacement surgery?

Answer: You are not alone. Millions of Americans face this very question. And more than 700,000 of them will have one or both knee joints replaced this year. The usual cause is osteoarthritis, commonly known as wear-and-tear arthritis.

Age itself is no barrier, and about half of total knee replacements go to people 65 and older. Replacing a joint damaged by osteoarthritis helps people stay active and independent.

But with joint replacement, timing is key. If you jump the gun and get the procedure too soon, you might not see enough improvement to make the surgery worth it. But if you wait too long, you may subject yourself to unnecessary pain and disability.

To help you make the decision, your orthopedic surgeon will assess your symptoms, the extent of damage to the joint, and how much the joint problems limit your daily activities.

The main symptoms of knee osteoarthritis are pain and stiffness. Having major surgery makes little sense if the pain and stiffness are mild, since you could expect minimal improvement and yet face the same risks as everybody else. Moderate to severe pain, however, points to a possible need for joint replacement.

Your surgeon will assess the amount of joint damage, such as how much cartilage has broken down. This leaves bone rubbing on bone. The joint may start to move at abnormal angles. The range of motion of the joint may decrease. The severity and consequences of joint damage help decide timing of knee replacement.

How much does knee arthritis limit your ability to do the things you need to do and enjoy doing? Only you can answer that question. For example, if taking acetaminophen, ibuprofen or naproxen isn’t enough to keep you walking or relieve your pain, now is the time to consider surgery.

(Howard LeWine, M.D., is an internist at Brigham and Women’s Hospital in Boston and assistant professor at Harvard Medical School. For additional consumer health information, please visit www.health.harvard.edu.)