TOTAL KNEE REPLACEMENT
If your knee is severely damaged by arthritis or injury, it may be hard for you to perform simple activities, such as walking or climbing stairs. You may even begin to feel pain while you are sitting or lying down.
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If nonsurgical treatments like medications and using walking supports are no longer helpful, you may want to consider total knee replacement surgery. Joint replacement surgery is a safe and effective procedure to relieve pain, correct leg deformity, and help you resume normal activities.
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Knee replacement surgery was first performed in 1968. Since then, improvements in surgical materials and techniques have greatly increased its effectiveness. Total knee replacements are one of the most successful procedures in all of medicine. According to the Agency for Healthcare Research and Quality, in 2017, more than 754,000 knee replacements were performed in the United States.
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Whether you have just begun exploring treatment options or have already decided to have total knee replacement surgery, this article will help you understand more about this valuable procedure.
Total Knee Replacement
Patient Specific
The surgeon and the team wearing body exhaust suits.
Anatomy
The knee is the largest joint in the body and having healthy knees is required to perform most everyday activities.
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The knee is made up of the lower end of the thighbone (femur), the upper end of the shinbone (tibia), and the kneecap (patella). The ends of these three bones are covered with articular cartilage, a smooth substance that protects the bones and enables them to move easily within the joint.
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The menisci are located between the femur and tibia. These C-shaped wedges act as "shock absorbers" that cushion the joint.
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Large ligaments hold the femur and tibia together and provide stability. The long thigh muscles give the knee strength.
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All remaining surfaces of the knee are covered by a thin lining called the synovial membrane. This membrane releases a fluid that lubricates the cartilage, reducing friction to nearly zero in a healthy knee.
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Normally, all of these components work in harmony. But disease or injury can disrupt this harmony, resulting in pain, muscle weakness, and reduced function.
Knee Anatomy
The Largest Joint
Apart from bone various soft tissue structures can get injured within the knee.
Cause
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The most common cause of chronic knee pain and disability is arthritis. Although there are many types of arthritis, most knee pain is caused by just three types: osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis.
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Osteoarthritis. This is an age-related "wear and tear" type of arthritis. It usually occurs in people 50 years of age and older, but may occur in younger people, too. The cartilage that cushions the bones of the knee softens and wears away. The bones then rub against one another, causing knee pain and stiffness.
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Rheumatoid arthritis. This is a disease in which the synovial membrane that surrounds the joint becomes inflamed and thickened. This chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain, and stiffness. Rheumatoid arthritis is the most common form of a group of disorders termed "inflammatory arthritis."
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Post-traumatic arthritis. This can follow a serious knee injury. Fractures of the bones surrounding the knee or tears of the knee ligaments may damage the articular cartilage over time, causing knee pain and limiting knee function.
Knee Arthritis
Damaged Joint
Damage to the articular cartilage results in bone rubbing against bone.
Description
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A knee replacement (also called knee arthroplasty) might be more accurately termed a knee "resurfacing" because only the surface of the bones are replaced.
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There are four basic steps to a knee replacement procedure:
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Prepare the bone. The damaged cartilage surfaces at the ends of the femur and tibia are removed along with a small amount of underlying bone.
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Position the metal implants. The removed cartilage and bone is replaced with metal components that recreate the surface of the joint. These metal parts may be cemented or "press-fit" into the bone.
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Resurface the patella. The undersurface of the patella (kneecap) is cut and resurfaced with a plastic button. Some surgeons do not resurface the patella, depending upon the case.
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Insert a spacer. A medical-grade plastic spacer is inserted between the metal components to create a smooth gliding surface.
Knee Replacement
TKR Implant
The standard TKR implant is made of cobalt chrome alloy with a Polythene spacer.
Is Total Knee Replacement for You?
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The decision to have total knee replacement surgery should be a cooperative one between you, your family, your primary care doctor, and your orthopaedic surgeon. Your doctor may refer you to an orthopaedic surgeon for a thorough evaluation to determine if you might benefit from this surgery.
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When Surgery Is Recommended?
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There are several reasons why your doctor may recommend knee replacement surgery. People who benefit from total knee replacement often have:
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Severe knee pain or stiffness that limits everyday activities, including walking, climbing stairs, and getting in and out of chairs. It may be hard to walk more than a few blocks without significant pain and it may be necessary to use a cane or walker
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Moderate or severe knee pain while resting, either day or night
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Chronic knee inflammation and swelling that does not improve with rest or medications
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Knee deformity — a bowing in or out of the knee
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Failure to substantially improve with other treatments such as anti-inflammatory medications, cortisone injections, lubricating injections, physical therapy, or other surgeries
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Realistic Expectations
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An important factor in deciding whether to have total knee replacement surgery is understanding what the procedure can and cannot do.
Most people who have total knee replacement surgery experience a dramatic reduction of knee pain and a significant improvement in the ability to perform common activities of daily living. But total knee replacement will not allow you to do more than you could before you developed arthritis.
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With normal use and activity, every knee replacement implant begins to wear in its plastic spacer. Excessive activity or weight may speed up this normal wear and may cause the knee replacement to loosen and become painful. Therefore, most surgeons advise against high-impact activities such as running, jogging, jumping, or other high-impact sports for the rest of your life after surgery.
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Realistic activities following total knee replacement include unlimited walking, swimming, golf, driving, light hiking, biking, ballroom dancing, and other low-impact sports.
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With appropriate activity modification, knee replacements can last for many years.
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