Replacing a Bad Knee

Knee replacement surgery can relieve severe arthritis pain and may help you walk easier. Wear and tear, illness, or a knee injury can damage the cartilage around your knee bones and prevent the joint from working well. If your arthritis symptoms are severe, your doctor may recommend knee replacement.

What Is Knee Replacement?

During knee replacement surgery, the surgeon removes damaged cartilage and bone from the knee joint and replaces them with a manmade joint. The operation is also called knee arthroplasty, and it's one of the most common orthopaedic surgeries in the U.S.

Symptoms of Knee Arthritis

Common types of arthritis include osteoarthritis, rheumatoid arthritis, and arthritis developed after an injury. Regardless of what type you have, the main symptoms of knee arthritis are pain, swelling, and stiffness in the knee. Over time, the knee may become so stiff that walking is hard or even impossible. You may have other symptoms too, depending on your specific type of arthritis.

Osteoarthritis of the Knee

The cartilage that cushions the knee joint can wear away as you age, allowing bone to rub against bone. The result is that normal motions of the knee become increasingly painful. This "wear and tear" is known as osteoarthritis, and it is most common in people over 50.

Rheumatoid Arthritis

Rheumatoid arthritis is a chronic illness in which the body's immune system mistakenly attacks the joints, causing pain and swelling. While osteoarthritis may strike just one knee, rheumatoid arthritis tends to affect both sides of the body. It can also affect the hands, wrists, and feet. RA can also cause other symptoms, such as fever and fatigue.

Post-Injury Arthritis

In some cases, arthritis develops after an injury like breaking a knee bone or tearing one of the knee's ligaments. The arthritis may not occur right after the injury. Damaged bones or ligaments can lead to damaged cartilage over time, eventually causing pain and stiffness.

When to Consider Surgery

Knee replacement surgery may help you if other arthritis treatments don't work and you have any of the following:

• Limited ability to walk
• Inability to get in or out of a chair
• A bowing in or out of the knee
• Moderate to severe pain when resting

Preparing Your Home

If you decide to have knee replacement surgery, think about making some changes at home ahead of time:

• Install safety bars in the bath or shower.
• Remove throw rugs and things you can trip over.
• Buy a footstool for keeping your leg up.

You should also ask someone to help you with daily activities during the first few weeks of your recovery.

What Happens During Surgery?

Knee replacement usually takes one to two hours. The surgeon removes damaged cartilage and bone from the knee. Then the doctor attaches metal implants to the ends of the thigh and calf bones. A plastic spacer separates the metal pieces and allows the new joint to move smoothly.

Your Hospital Stay

Most people spend several nights in the hospital after knee replacement surgery. You will take pain medication and be encouraged to move your foot and ankle soon afterward. Moving around increases blood flow to the leg muscles and can help reduce swelling.

Continuous Passive Motion

You will probably start exercising your knee the day after surgery. A physical therapist can show you how to strengthen the muscles that support your new joint. Your doctor may suggest you use a continuous passive motion machine, which slowly moves the knee for you while keeping the leg raised. This movement helps reduce swelling and improves blood flow.

Back at Home

When you get back home from the hospital, you will be able to walk with crutches or a walker. But you may need help bathing, cooking, and with household chores for the first three to six weeks. If you live alone, you may want to stay in a rehab center until you can do daily activities by yourself.

Keep on Moving

To make the most of your new knee, you should follow your doctor's instructions about physical activity in the weeks after the surgery. Too much rest can slow your recovery, but you don't want to overdo it, either. Focus on moving around your house, taking walks, and doing the exercises recommended by your physical therapist.

Physical Therapy

Physical therapy for knee replacement includes exercises to improve flexibility and strengthen the muscles surrounding the joint. You can do these exercises at a physical therapy center or at home, but be sure to ask the therapist how to do them properly. You should continue doing them for at least two months after surgery.

How Long Is the Recovery?

All patients heal from surgery at their own pace, but here are some guidelines to return to common activities:

• Household chores: 3-6 weeks
• Sex: 4-6 weeks
• Work: 6-8 weeks
• Swimming: 6-8 weeks
• Driving: 6-8 weeks for the right knee. (You may be able to drive after a week if your left knee was replaced.)

Risks of Surgery

Knee replacement is safe for most people, but all surgery involves risks, including:

• A scar that is unattractive or painful
• An infection or heavy bleeding
• A blood clot in the leg

Preventing Blood Clots

Some people develop blood clots after knee surgery. Clots tend to develop a few days after the surgery, usually in the calf or thigh. Symptoms are swelling and pain. A clot may lead to life-threatening situations if it breaks off and travels to the lungs. Support hose, compression devices, and blood thinners can reduce the risk of clots. Foot and ankle movement may help too, so it's important to move around as soon as you are able.

When to Seek Emergency Care

Warning signs of a blood clot in the lungs (pulmonary embolism) include sudden shortness of breath, chest pain, and coughing. Signs of infection include fever, worsening redness or tenderness of the knee, and pus draining from the surgical wound. If you feel or see any of these symptoms after knee replacement, call your doctor immediately.

Problems With Knee Implants

Knee implants continue to get more sophisticated, but they are not fail proof. They can wear down over time or may come loose from the bone. Scar tissue can grow around an implant, limiting its range of motion. And even when working properly, implants can cause a clicking sound as the knee bends back and forth.

Protecting Your Knee Implant

You can extend the life of your knee implant by taking several steps. After surgery, use a cane or walker until your balance improves -- taking a fall can cause serious damage to your new joint. High-impact exercise can also take a toll on knee implants, so most doctors warn against jogging, jumping, and contact sports.

Outlook for Knee Replacement

While some activities are off-limits after a knee replacement, you still have plenty of others to choose from. Unlimited walking, golf, light hiking, cycling, ballroom dancing, and swimming are all considered safe for people with knee implants. By following your doctor's guidelines, you can expect long-lasting results -- more than 90% of knee implants are still working well 15 years after surgery.

Related Reading

• Quiz: Do You Know How to Relieve Your Arthritis Pain?
• 6 Ways to Ruin Your Knees
• WebMD Osteoarthritis Community
• Video: Treating Arthritis -- A Personal Story
• Tool: Are You Coping With Chronic Pain?
• Exercises for Knees and Hips