Knee Replacement Surgery Information

Knee replacement surgery is performed to replace a damaged knee joint with an artificial joint (prosthesis) made from metal and plastic. There are two types of knee replacements, a total replacement, during which the entire joint is replaced, and a partial, or unicompartmental, replacement that is performed when only one part of the knee is damaged. Total-knee replacements are the most common and this article provides information on the total replacement surgery and recovery process.

Causes

• Osteoarthritis is the main cause of knee replacement. In a healthy knee, cartilage covers the ends of the femur (thighbone), the tibia (shinbone) and the back of the patella (knee cap) to keep the bones from grinding together and to help the knee move smoothly. Osteoarthritis causes the cartilage to wear away, which allows the bones to rub together causing pain and stiffness. Rheumatoid arthritis and trauma also are leading causes of knee replacement. Rheumatoid arthritis causes the synovial membrane in your knee to become inflamed and this inflammation damages the cartilage resulting in pain and stiffness.

Surgery

• Replacement surgery is usually done after more conservative methods such as physical therapy and knee injections have failed. Other factors in the decision include: constant knee pain, inability to sleep because of knee pain, inability to work, or the inability to walk more than three blocks because of pain.
  Total-knee replacement surgery takes two to four hours. Your surgeon will start by making a four to 10 inch incision on the top of your knee with a scalpel. She will then remove your knee cap and clip away cartilage and bone spurs from your joint with a heavy duty cutting instrument called a rongeur. The femur, tibia and patella are shaped with a bone saw and then the prosthesis is attached to the three bones with a special cement that binds metal and plastic to bone. Finally, the incision is closed using either staples or sutures

Recovery

• You will be in the hospital three to five days following surgery, but you will be on your feet very quickly. You will be out of bed and walking the day after your surgery and you will attend physical therapy sessions twice a day at the hospital until you are discharged. After leaving the hospital, you will go to outpatient physical therapy two to three times a week for two to six months. In addition, you will have daily exercises to do at home to help with the bending (flexing) and straightening (extension) of your new knee.

Resuming Activities

• You will be able to resume many of your daily activities, such as driving or returning to work, in six to eight weeks after surgery, but it can take up to one year before you gain full range of motion in your knee. Once you complete your physical therapy, you can resume most exercises including walking, swimming and golf. Avoid high-impact exercises like running, jogging or contact sports.

Risks

• The risks of knee-replacement surgery include bleeding, infection, adverse reaction to the anesthesia, and damage to nearby blood vessels, bones or nerves. You also must treat any bacterial infection immediately because it can spread very quickly through your bloodstream to your new joint. This includes even minor sinus, urinary tract, respiratory or dental infections.