Knee replacement surgery restores the weight-bearing façade of a damaged, worn, or diseased knee joint. The aim is to remove pain and restore mobility. It is also known as knee arthroplasty, or "knee resurfacing."
The surgeon caps the ends of the bones that form the knee joint with metal or plastic components, or implants a prosthetic, shaped as a joint. This enables the knee to move properly.Replacement knee surgery can help patients whose knee or knees have degenerated due to osteoarthritis, rheumatoid arthritis, or post-traumatic arthritis, when an injury has damaged the knee. It is considered a routine procedure. Every year, over 600,000 knee replacement surgeries are carried out in the United States. Most patients are aged between 50 and 80 years. Over 90 percent of patients experience a dramatic improvement in pain levels and mobility. As long as the patient follows the surgeon's instructions for knee care, in 90 percent of cases, a replacement knee still functions well after 15 years, and 80 to 85 percent of replacements last 20 years.
What is knee replacement and why is it useful?
Knee replacement is a kind of arthroplasty. Arthroplasty literally means "the surgical repair of a joint," and it involves the surgical reconstruction and replacement of degenerated joints, using artificial body parts, or prosthetics.
When the articular cartilage of the knee becomes damaged or worn, it becomes painful and the knee is hard to move. Instead of sliding over each other, the bones rub and crush together.
With a prosthesis, the patient will feel less pain, and the knee will move properly.
Why have knee replacement surgery?
There are three common reasons for the procedure:
Osteoarthritis: this type of arthritis is age related, caused by the normal wear and tear of the knee joint. It mostly affects patients aged over 50 years, but younger people may have it.
Osteoarthritis is caused by inflammation, breakdown, and the gradual and eventual loss of cartilage in the joints. Over time, the cartilage wears down and the bones rub together. To compensate, the bones often grow thicker, but this results in more friction and more pain.
Rheumatoid arthritis: also called inflammatory arthritis, the membrane around the knee joint to become thick and inflamed. Chronic inflammation damages the cartilage, causing soreness and stiffness.
Post-traumatic arthritis: this type of arthritis is due to a severe knee injury. When the bones around the knee break or the ligaments tear, this will affect the knee cartilage.
Who might need a knee replacement?
Knee surgery may be suitable for patients who experience:
Severe knee pain or stiffness that prevents them from carrying out everyday tasks and activities, such as walking, going upstairs, getting in and out of cars, getting up from a chair
Moderate but continuous knee pain that continues while sleeping or resting
Chronic knee inflammation and swelling that does not improve after taking medications or resting
Knee deformity, where there is a noticeable arch on the inside or outside of the knee
Depression, resulting from an inability to carry out daily or social activities
If the other available treatment options have not worked, surgery may be the best option.
Types of knee replacement surgery
Knee replacement can be total or partial.
Total knee replacement (TKR): Surgery involves the replacement of both sides of the knee joint. It is the most common procedure.
Surgery lasts between 1 and 3 hours. The individual will have less pain and better mobility, but there will be scar tissue, which can make it difficult to move and bend the knees.
Partial knee replacement (PKR): Partial replacement replaces only one side of the knee joint. Less bone is removed, so the incision is smaller, but it does not last as long as a total replacement.
PKR is suitable for people with damage to only one part of the knee. Post-operative rehabilitation is more straightforward, there is less blood loss and a lower risk of infection and blood clots.
The hospital stay and recovery period are normally shorter, and there is a higher chance of more natural movement.
Preparing for surgery
Knee arthroplasty involves major surgery, so pre-operative preparation, medical consultations, and physical evaluations usually begin a month before the set date of the operation.
Preparatory and diagnostic tests will include checking blood count, seeing how the blood clots, carrying out electrocardiograms (ECGs), and urine tests.
Surgery is usually performed either under general, spinal, or epidural anesthetic.
During the procedure, the orthopedic surgeon will remove the damaged cartilage and bone, and then position the new implant, made of metal, plastic, or both, to restore the alignment and function of the knee.
A patient who has knee replacement surgery will be hospitalized for 1 to 3 days, depending on how well they follow and respond to rehabilitation.
There will be pain, but a day after the procedure medical staff will encourage patients to get up and try to walk about, usually with some kind of walking aid. It is important to follow the instructions for rehabilitation.
Physical therapy sessions aim to strengthen the knee. These may be painful, but they significantly reduce the risk of future complications.
Patients who do not have help at home may need to stay in the hospital for longer.
(Image: Representation only) Medisense Healthcare