All Conditions & Treatments

How Do You Know if You Need a Knee Replacement?

By Steven B. Haas, MD, on behalf of the Adult Reconstruction and Joint Replacement Service

Knee replacement is a surgery that’s done to treat osteoarthritis of the knee. This type of knee arthritis is a condition that occurs as people get older, when the cartilage that provides cushioning in the bones of the knee joint begins to degenerate and wear away. This causes the bones to rub together, resulting in significant pain. It also can lead to inflammation and swelling, which may affect your ability to bend and straighten your leg.

Man holding knee in pain.

Degeneration of the cartilage in the knee may be worse or occur earlier in life if you have had a prior knee injury. Obesity can also make it more severe since there is more weight being placed on the joints.

The term “knee replacement” may sound scary to some people. It makes the surgery sound very different from what it actually is. What we do in a modern knee replacement is replace the surfaces of the knee joint, not the joint itself. The tendons, ligaments and all the other structures around the knee are left in place. I sometimes compare it to a dentist capping a tooth: We are adding new caps to the bones.

Here are a few questions to help you determine whether you might need a knee replacement and if so, which type.

Could a nonsurgical option be right for you?

If you’re having problems with knee pain and swelling due to osteoarthritis, there are a number of nonsurgical treatments you can try. Anti-inflammatory drugs such as ibuprofen, certain exercises to strengthen the muscles around the knee and injections offer relief for many people.

If these measures work for you, you don’t need to have surgery. But if it gets to the point where you’re staying home because it hurts too much to walk, or you’re unable to do simple activities like climbing stairs, it may be time to seriously consider having knee replacement surgery.

Do you meet the criteria for a knee replacement?

To qualify for a knee replacement, you need to meet two major requirements. One is that you have a significant amount of cartilage loss. This is usual evaluated by taking X-rays of the knee while you are in a standing position. The loss of cartilage is seen as narrowing of the space between the knee bones. The other is that the loss is bad enough that it’s having a negative impact on your quality of life – due to pain, limited function or a combination of the two.

Usually by the time people come to one of the knee replacement surgeons at HSS, they have tried everything else and are ready to have surgery.

Is partial knee replacement an option?

The knee is divided into three compartments:

  • the medial compartment (the inside part)
  • the lateral compartment (the outside part)
  • the patellofemoral compartment (the kneecap)

If you have a problem in only one of the three compartments, you may be able to have what is called a partial knee replacement. Since only one area of the knee is resurfaced, recovery from partial knee replacement is faster. Because many patients have arthritis in more than one knee compartment, the majority of people who undergo knee replacement surgery about – 90% – need to have all three compartments resurfaced. This is called a total knee replacement, or total knee arthroplasty.

Should you have both knees replaced at the same time?

Many people with osteoarthritis have problems with both knees, but usually one knee is worse than the other. Most people have surgery on one knee at a time, though some patients want to have surgery on both knees at the same time. The plus side of this is that you only need one operation, but the downside is that it’s a harder, slower recovery.

There are strict criteria for having both knees operated on at the same time, including being in overall good health and being motivated to undergo a more difficult recovery.

Why come to HSS for your knee replacement?

I call knee replacement surgery a team sport. The two most central players are the surgeon and the patient, but there are many other people on the team who help make it successful. At HSS, our knee replacement surgeons are among the most skilled surgeons in the world. In addition to their deep expertise and extensive training, they have a singular focus on joint replacement surgery. This experience allows them to achieve very high success rates, avoid complications and help effectively relieve our patients’ pain.

Another advantage is that the knee replacement surgeons at HSS embrace the multidisciplinary aspects of orthopedic care. They work closely with anesthesiologists, rehabilitation specialists, nurses, dietitians, and many others to keep our patients safe and healthy so they can get back to what they love to do.

The fact that HSS is a specialty hospital focused solely on orthopedics and rheumatology is a great advantage. All our staff have great experience and a singular focus. Since we do not have to compete with other departments for resources, we can concentrate all our efforts on obtaining the best outcomes for our patients without any compromise.

About the expert

Dr. Steven B. Haas is Chief of the Knee Service at HSS and holds the John N. Insall Chair in Knee Surgery. He is a leader in advancing surgical techniques and pain control, which allows for more rapid recovery from knee replacement.


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