Total Knee Replacement
The Initial Evaluation
During the initial evaluation, your knee problem and medical history will be reviewed. If you have had previous treatment for your knee pain and/or x-rays, it is important to bring these records with you. The objective of this first visit is to determine whether knee surgery is indicated. This decision is based upon many factors, which include your degree of pain, severity of limp, the extent of decreased mobility, and your overall dissatisfaction with your condition. Another important consideration is your current health status. After evaluating your x-rays and completing the physical examination, I will be able to discuss with you the relative advantages and disadvantages of a surgical procedure and what the outcomes should be.
Your knee is one of the largest, most important joints in your body. Its strength and complexity enable you to perform many movements everyday. When a person experiences problems with their knee such as pain or stiffness, it becomes difficult to complete everyday activities.
Problems with the knee may resolve over time, but sometimes pain or stiffness of the knee joint becomes progressively worse. This is often the case when a person is suffering from arthritis of the knee joint. When a knee has been arthritic for a long time, treatments that have been successful in the past, such as medications, injections, bracing, or physical therapy, may no longer help. Based on your age, your level of knee pain, and the amount of damage to your knee, total knee replacement surgery may be the best option for you.
The Normal Knee Joint
Your knee joint is made up of the ends of the femur or thigh bone, the tibia or shin bone, and the patella or knee cap. The ends of the femur and the tibia are covered with protective cartilage. The patella rests on the femur and is also backed with a cartilage layer. In between the femur and tibia are cushions of cartilage that provide padding to the joint. Strong ligaments and muscles hold the knee joint together and in correct alignment. The tissue capsule surrounding the knee joint has a membrane which produces fluid that lubricates the knee joint surface.
The Arthritic Joint
When a joint becomes arthritic, degeneration and inflammation of the cartilage, bone, and surrounding tissues occurs. Arthritis generally presents later in life and is characterized by the gradual onset of pain, disability, and deformity. However, this process can occur more rapidly in younger individuals, particularly if the joint has been injured. The most common form of arthritis is osteoarthritis (degenerative arthritis). Arthritis may also be caused by inflammation (rheumatoid arthritis) or be a result of trauma. Regardless of the initial type of arthritis, the result is permanent and pro- gressive damage to the cartilage and bone.
As the knee becomes arthritic the soft cartilage cushions between the bones begin to wear away. Without this protective padding the ends of the bones rub together. Under stress from activity, the bones begin to grind together resulting in bone loss, cyst formation, spurring, and deformity. The person with severe arthritis of the knee may notice pain with standing, walking, and kneeling. The knee may feel unstable and motion may become limited.
How do I know if I am a candidate for knee replacement surgery?
Knee replacement surgery is typically indicated for individuals that are no longer benefiting from non-surgical treatments, such as medication, therapy, braces, injections, and activity modification. When the pain and interference in daily activities is significant and quality of life is diminished, surgery should be considered. A knee replacement can last many years and result in much improvement in overall health and well-being. However, if you are still relatively young, knee replacement may not be the best choice, and other surgical options may be considered.
What is total knee replacement?
Total knee replacement is also known as total knee arthroplasty or TKA. The surgery involves resurfacing the ends of the bones with artificial implant materials made of metal and polyethylene plastic. One should think of knee replacement as a resurfacing of the joint rather than a replacement of the whole joint. Typically, a thin (less than 1cm) layer of cartilage and underlying bone is removed and replaced with the prosthesis. There are several designs of knee replacement implants. Total knee replacement involves three parts or components. The components are fixed to the bone by acrylic bone cement or with a surface that allows for bone ingrowth. The patellar component is high-density polyethylene plastic. The femoral component is metal, and the tibial component is plastic that attaches to a metal tray.
Are there other types of knee replacement surgery?
Two other types of knee replacement surgery include replacing only one part of the knee and revising a previous knee replacement implant. These are much less common. A person may be a candidate for partial knee replacement if only one compartment is damaged and there is little deformity. A revision knee replacement may be indicated for a patient whose previous knee replacement has failed.
How long does a knee replacement last?
Most knee replacements will last a lifetime. However, it should be remembered that the implant is a mechanical device inside of the body. Therefore, it is subject to loosening from the bone, wearing out, infection, and other unforeseen events. We know that modern knee replacements have a 90% chance of remaining functional after 10 years and 80% after 20 years.
What are the benefits?
Many people experience long-lasting benefits after knee replacement surgery. Joint pain is significantly reduced or completely gone. A person may look forward to being able to move the joint more freely and having more mobility than prior to surgery. Deformities of the knee joint are corrected and one is able to strengthen the leg with exercise. Most of all, quality of life improves as one is able to return to regular activities.
What are the risks?
Any major surgery is associated with risks. These risks include, but are not limited to, anesthesia or medical complications such as heart problems, stroke, pneumonia, or urinary infection. Important risks specific to knee replacement surgery are infection, blood clots in the legs or lungs, stiffness, wound problems, leg length inequality, implant dislocation, and damage to blood vessels, bones, ligaments, tendons, or nerves. Over the long-term, infection, loosening, wear, or breakage of the implant are possible complications.
