What is a knee joint?

The knee is the largest joint in the body that consists of the following:
- Femur (lower end of the thighbone)
- Tibia (the upper end of the shinbone)
- Patella (the kneecap)
The ends of these three bones are covered with a smooth substance called the articular cartilage that protects the bones and enables joint movement. All 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. Normally, all these components work in harmony. However, a disease or an injury can disrupt this harmony, resulting in pain, muscle weakness, and reduced function.
What is total knee arthroplasty?
If an individual’s knee is severely damaged by joint swelling or an injury, it may be hard for them to perform simple activities such as walking or climbing stairs. They may even begin to feel pain when they are sitting or lying down.
If nonsurgical treatments, such as medications and using walking supports, are no longer helpful, the patient may consider a surgical procedure called a total knee replacement surgery or total knee arthroplasty (TKA).
Joint replacement surgery is a safe and effective procedure to relieve pain, correct leg deformity, and help the individual resume normal activities. In this procedure, the diseased or injured knee joint is replaced with artificial material.
When does an individual require total knee joint replacement?

Most patients who undergo total knee replacement are between 50 and 80 years old. The total knee replacement surgery is considered for patients whose knee joints have been damaged by the below conditions:
- Osteoarthritis: It is a degenerative joint disease. Patients with this condition are unable to do normal activities due to severe pain. The knee may swell or "give way" because the joint is not stable. It is the most common cause of total knee arthroplasty (TKA).
- Rheumatoid arthritis: This is a disease in which the synovial membrane that surrounds the joint becomes swollen and thickened. This severe swelling can damage the cartilage and eventually cause pain and stiffness. It is the most common form of a group of disorders termed "inflammatory arthritis."
- Severe injury to the knee.
- Knee joint deformity by birth.
What is replaced in total knee arthroplasty?

The artificial components of a total knee replacement are referred to as a prosthesis.
- During total knee replacement, the end of the femur bone is removed and replaced with a metal shell. The end of the tibia (lower leg bone) is also removed and replaced with a channeled plastic piece with a metal stem.
- Depending on the condition of the kneecap portion of the knee joint, a plastic "button" may also be added under the kneecap surface.
- The posterior cruciate ligament is a tissue that normally stabilizes each side of the knee joint so that the lower leg cannot slide back to the thighbone. In the total knee replacement surgery, this ligament is retained, sacrificed, or substituted by a polyethylene post.

QUESTION
Medically speaking, the term "myalgia" refers to what type of pain? See AnswerWhat happens during total knee arthroplasty?
Total knee arthroplasty (TKA) is major surgery and usually performed under general or spinal anesthesia. Usually, the surgery is completed within three hours, depending upon the patient’s condition.
- The surgeon monitors the patient’s vitals throughout the procedure.
- The surgeon cleanses the skin over the surgical site with an antiseptic solution.
- The orthopedic surgeon will make an incision in the knee area.
- The surgeon may remove the damaged surfaces of the knee joint and resurface the knee joint with the prosthesis. The prosthesis generally comprises three components: the tibial component (to resurface the top of the tibia or shin bone), the femoral (thigh bone) component (to resurface the end of the thighbone), and the patellar component (to resurface the bottom of the kneecap that rubs against the thighbone).
- The surgeon closes the incision with stitches or surgical staples.
- The surgeon may place a drain in the incision site to remove the fluid.
- The surgeon will apply a sterile bandage or dressing.
- The patient may be on painkillers and antibiotics. They will be monitored in the intensive care unit (ICU) until they wake up from anesthesia. Depending on the patient’s condition, they may be shifted to the hospital room later.
What are the risks of total knee arthroplasty?

Some possible complications of total knee arthroplasty may include the following:
- Bleeding
- Infection
- Blood clots in the legs or lungs
- Loosening or wearing out of the prosthesis
- Fracture
- Continued pain or stiffness
- Nerves or blood vessels in the area of surgery may be injured, resulting in weakness or numbness. The joint pain may not be relieved by the surgery.
Health News
- One Death, 10 Hospitalizations in Listeria Outbreak Tied to Peaches, Plums
- Charity Scams Get Active Over the Holidays: Expert Tips to Avoid Them
- Too Few Seniors Get Follow-up Care After a Serious Fall
- AI Could Predict a Nonsmoker's Risk for Lung Cancer
- Breast Cancer Rates Higher in Urban vs. Rural Areas
More Health News »
Health Solutions From Our Sponsors
Medscape Medical Reference
Top What Is Total Knee Arthroplasty (TKA) Related Articles
Arthritis (Joint Inflammation)
Arthritis is inflammation of one or more joints. When joints are inflamed they can develop stiffness, warmth, swelling, redness and pain. There are over 100 types of arthritis, including osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and gout.Arthritis: 16 Bad Habits That Cause Joint Pain
Being overweight, wearing uncomfortable shoes, or carrying a heavy purse can make joint pain and arthritis symptoms worse. Some bad habits increase inflammation and put you at risk of osteoarthritis and rheumatoid arthritis. Protect joints and muscles and prevent swelling and joint disorders by eliminating these joint problem bad habits.Physical and Occupational Therapy for Arthritis
Physical therapy can help a patient with arthritis to work out stiffness without damaging their joints. Occupational therapy teaches the patient how to reduce joint strain during daily activities. Those receiving occupational or physical therapy will learn about their arthritis, be given a dietary plan if they are overweight, get foot care advice, and learn methods of relieving discomfort.Fungal Arthritis
Fungal arthritis is inflammation of a joint by a fungus that has invaded the body and is growing in the normally sterile joint. Fungal arthritis symptoms and signs include pain, redness, loss of range of motion, and swelling. Fungal arthritis treatment includes antibiotics, adequate drainage of the joint, and sometimes surgery.Gout
Buildup of uric acid crystals in a joint causes gouty arthritis. Symptoms and signs include joint pain, swelling, heat, and redness, typically of a single joint. Gout may be treated with diet and lifestyle changes, as well as medication.Hip Bursitis
Bursitis of the hip results when the fluid-filled sac (bursa) near the hip becomes inflamed due to localized soft tissue trauma or strain. Symptoms include stiffness and pain around the hip joint. If the hip bursa is not infected, hip bursitis can be treated with ice compresses, rest, and anti-inflammatory and pain medications.Osteoarthritis (OA or Degenerative Arthritis)
Osteoarthritis, or degenerative arthritis, is a type of arthritis caused by inflammation, breakdown, and eventual loss of cartilage in the joints. Osteoarthritis can be caused by aging, heredity, and injury from trauma or disease.OA & Your Joints
Dealing with joint pain and arthritis? Learn why weight matters--and why NOT to stretch before exercise. See these solutions for joint pain and tips to protect your joints from damage.Osteoarthritis Slideshow
Osteoarthritis (OA) is a degenerative joint disease most often affecting major joints such as knees, hands, back, or hips. Osteoarthritis symptoms include pain, swelling and joint inflammation.Osteoarthritis Quiz
How does osteoarthritis differ from other types of arthritis? Learn about osteoarthritis with this quiz.Osteoarthritis vs. Osteoporosis Differences and Similarities
Arthritis is defined as painful inflammation and joint stiffness. Osteoarthritis is a type of arthritis and the most common cause of chronic joint pain, affecting over 25 million Americans. Osteoarthritis is a type of arthritis that involves the entire joint. Osteoporosis is not a type of arthritis. It is a disease that mainly is caused by a loss of bone tissue that is not limited to the joint areas. It is possible for one person to have both osteoarthritis and osteoporosis. The differences in the signs and symptoms of osteoarthritis and osteoporosis include; pain, stiffness, and joint swelling, joint deformity, crackle sounds when the joint is moving, and walking with a limp. Osteoporosis is called the "silent disease" because it can progress for years without signs and symptoms before it is diagnosed, severe back pain, bone fractures, height loss, and difficulty or inability to walk. The differences in the causes of osteoarthritis and osteoporosis are that osteoarthritis usually is caused by wear and tear on the joints. Osteoporosis usually is caused by one or more underlying problems, for example, calcium and vitamin D deficiencies. Treatment for osteoarthritis and osteoporosis are not the same. There is no cure for osteoarthritis or osteoporosis.Psoriatic Arthritis Picture
Psoriatic arthritis is a specific condition in which a person has both psoriasis and arthritis. See a picture of Psoriatic Arthritis and learn more about the health topic.Psoriatic Arthritis Quiz
How is psoriatic arthritis related to psoriasis? Take this quiz to find out!Rheumatoid Arthritis (RA)
Rheumatoid arthritis (RA) is an autoimmune disease that causes chronic inflammation of the joints, the tissue around the joints, as well as other organs in the body.16 Early Rheumatoid Arthritis (RA) Signs & Symptoms
Early rheumatoid arthritis (RA) symptoms and signs vary differently from person to person. The most common body parts that are initially affected by RA include the small joints of the hands, wrists, and feet, and the knees and hip joints. Joint inflammation causes stiffness. Warmth, redness, and pain may vary in degree.RA Slideshow
What is rheumatoid arthritis (RA)? Learn about treatment, diagnosis, and the symptoms of juvenile rheumatoid arthritis. Discover rheumatoid arthritis (RA) causes and the best medication for RA and JRA.RA Quiz
How is rheumatoid arthritis different from other forms of arthritis, such as osteoarthritis and gout? Take the Rheumatoid Arthritis (RA) Quiz to rest your RA IQ.Knee Replacement Surgery and Recovery Time
During total knee replacement surgery, the diseased knee joint is replaced with artificial material. The risks include blood clots in the legs, urinary tract infection, nausea and vomiting, chronic knee pain, nerve damage, and infection.