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Knee Replacement

• Definition of Knee Replacement
• Description of Knee Replacement
• What Questions To Ask Your Doctor About Knee Replacement

Definition of Knee Replacement

Total knee replacement is a surgical procedure in which injured or damaged parts of the knee joint are replaced with artificial parts, called prostheses.

Description of Knee Replacement

The knee is the largest joint in the body. It is commonly known as the "hinge" joint, because it allows the knee to flex (bend) and extend (straighten), similar to the hinge on a door. The knee also has the ability to rotate (turn) and translate (glide).

The knee joint is composed of the tibia (shin bone), the femur (thigh bone) and the patella (kneecap). Each bone is covered with a layer of cartilage that cushions, protects and keeps the bones from rubbing together. Ligaments (bands of tissues) connect the femur and tibia, while muscles and tendons stabilize the knee and enable it to move. The patella helps protect the knee joint and anchor the tendons while allowing movement.

Reasons for Knee Replacement

The most common causes of knee joint damage are:

Who Is A Candidate For Knee Replacement?

A person would be considered for total knee replacement if there is:

• Daily pain
• The pain is severe enough to restrict work, recreation and ordinary activities of daily living
• Significant stiffness in the knee
• Significant instability (constant giving way) of the knee
• Significant deformity (knock-knees or bow-legs) that hinders normal function of the knee
• Damage from arthritic conditions, such as osteoarthritis, rheumatoid arthritis or post-traumatic arthritis

Evaluation

After understanding the symptoms, limitations and progression of the knee problem, the doctor will perform a variety of tests that may include measuring the knee's range of motion, analyzing muscle strength and evaluating the legs for variances, such as bow-legs or knock-knees. Additionally, an x-ray of the knee will be done to assess the damage. From the medical history, physical examination and test results, the doctor will determine if total knee replacement is necessary.

Preoperative Evaluation

Before surgery, joints adjacent to the damaged knee (such as the hip and ankle) are evaluated. Replacing a knee joint adjacent to a severely damaged joint may not yield significant improvement in knee function. All medications that the patient is taking prior to surgery are reviewed. Routine blood tests for liver and kidney function, as well as urine tests for signs of anemia, infection, or abnormal metabolism are given. A chest x-ray and an EKG are performed to exclude significant heart and lung disease which may preclude surgery or anesthesia.

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What Questions To Ask Your Doctor About Knee Replacement

Am I a candidate for total knee replacement?

How long after the surgery can normal activities resume?

What can and cannot be done with the new knee?

Will the new knee need to be replaced in the future?