Frequently Asked Questions About Arthritis of the Knee

What is arthritis and what causes it?

Arthritis is an umbrella term for a number of disease entities in which the joints become inflamed and the cartilage that lines the bones deteriorates. Eventually, bone on bone wear occurs. As the disease progresses, patients often experience pain, stiffness, and disability. The vast majority of people diagnosed have osteoarthritis and in most cases the cause of their condition cannot be identified. One or more joints may be affected. Rheumatoid arthritis (and other forms of inflammatory arthritis) is a disease that affects the entire system and multiple joints. This type of arthritis is an autoimmune disorder in which the body perceives the cartilage to be a foreign substance and attacks it.

If I have arthritis in one knee, will I get it in the other?

If you have been diagnosed with osteoarthritis, having an affected knee does not mean that you will develop arthritis in the opposite knee. About 40 percent of patients who have osteoarthritis in one knee will have the same condition in the other knee. In contrast, patients with rheumatoid arthritis often develop problems in both knees.

Why is my knee becoming more bow-legged or knock-kneed?

The increasing deformity of becoming more bow-legged or knock-kneed represents the greater wearing out of cartilage and bone from one side of the knee as compared to the other.

What is that cracking sound I hear in my knee?

The cracking sound represents the rough surfaces rubbing against one another. Instead of smooth cartilage sliding against cartilage, arthritic bone is rough and irregular, and will not glide well.

What kinds of things besides surgery can I do to help?

Modifying your activities to avoid those that bring on the pain may make your knee condition more bearable. In addition, losing weight will greatly decrease the forces across the knee joint, also reducing pain.

Are there any exercises that will help my knee arthritis?

Physical therapy often does help in early stages of arthritis of the knee. Your orthopedic surgeon can teach you some of these exercises that focus upon strengthening the quadriceps muscle. In addition, your surgeon may prescribe physical therapy for your knee to give you a structured program to follow.

Why should I have my knee replaced?

The decision to have a knee replacement is a personal one, and must take into account the risks and benefits of the procedure. Most patients will elect to have a total knee replacement when they can no longer bear the pain associated with their arthritis. Others will decide to have the surgery when they feel that their knee arthritis is preventing them from participating in activities that they enjoy.

What is the prosthesis made of?

The implant for a total knee replacement is made of a combination of metal and plastic. The metal parts are generally composed of cobalt chrome, and the plastic is made of ultra high molecular weight polyethylene.

Will I set off a metal detector?

While knee implants generally do not set off metal detectors, more sensitive machines may register the presence of the implant. Some physicians give their patients cards to show at the airport that explain that the bearer has received a knee prosthesis containing metal.

How long does the operation take?

The operation generally takes between 1 to 2 hours.

If both my knees have arthritis, can I have both replaced at the same time?

Yes, healthy patients younger than 75 years old, with no cardiopulmonary disease may be candidates for such surgery. Your orthopedist can tell you more about what is involved.

What kind of anesthesia is used?

Most total knee replacements at Hospital for Special Surgery are performed under regional anesthesia. It is called an epidural block, which is the same kind of anesthesia given to women in labor. The epidural anesthesia provides numbness from the waist down, so there will be no pain during surgery. In addition, patients are given a light sedative to make them as sleepy or awake as they want to be.

When will I be able to return to activity?

Your return to activity will be guided by your surgeon and therapists. Generally, patients are able to walk as much as they want by 6 weeks post-operatively. Patients are able to resume driving at 6 weeks. At 8 weeks, patients are able to resume playing golf and swimming; at 12 weeks, they may play doubles tennis.

How long will the replacement last?

Current studies indicated that about 85 percent of prostheses will function well for 20 years. If your prosthesis wears out you may be a candidate for a second knee replacement.

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