Knee replacement surgery, also known as knee arthroplasty, is an operation to resurface the weight-bearing surfaces of the knee joint in order to relieve pain and disability. It involves removing damaged or diseased bone and cartilage and replacing them with artificial implants called prostheses. These prostheses provide the patient with a painless, natural feeling knee joint.
Causes of Knee Pain
The most common causes of severe knee pain that may require knee replacement surgery are osteoarthritis and rheumatoid arthritis. Osteoarthritis occurs when the cartilage that cushions the ends of bones within the knee joint breaks down over time. This allows bones to rub against each other, causing pain, swelling and stiffness. Rheumatoid arthritis is an autoimmune disease where the body’s immune system attacks the lining of the joints, causing pain and swelling in the knee joints. Other less common causes of knee pain that may lead to knee replacement surgery include knee injuries like torn ligaments or cartilage, certain infections, and Paget’s disease.
Signs it’s Time for Knee Replacement
Some key signs that indicate a patient may benefit from knee replacement surgery include having severe knee pain even at rest or with low-impact activities, difficulty walking more than a few blocks at a time, difficulty going up or down stairs, the feeling that the knee may give out with certain activities, and persistent swelling and stiffness in the knee joint. An orthopedic surgeon will examine the patient and likely obtain x-rays and MRI scans of the knee to evaluate the amount of cartilage loss and bone damage present before recommending surgery.
Types of Knee Replacement Surgery
There are two main types of knee replacement surgery – partial knee replacement and total knee replacement. A partial knee replacement, also called unicompartmental knee replacement, only involves resurfacing the diseased areas on the inner or outer parts of the knee. It is typically used for arthritis that only affects one section of the knee. Total knee replacement involves resurfacing all three compartments of the knee, including the inner lining, the outer lining, and the undersurface of the knee cap. It provides the greatest degree of pain relief but has a longer recovery time.
How is Knee Replacement Surgery Performed?
During knee replacement surgery, the patient will receive either general anesthesia to be asleep or a spinal or epidural anesthesia to numb the lower half of the body. The surgeon makes an incision on the front of the knee. They then remove any diseased or damaged bone and cartilage from the ends of the thighbone (femur) and shinbone (tibia) as well as the underside of the knee cap (patella). Custom-fitted prosthetic parts made of metal alloys, high-grade plastics or ceramics are then attached using bone cement. These prosthetics replicate the natural movement of the knee joint. The incision is closed with sutures or surgical staples and a sterile bandage applied. The entire procedure usually takes 1-2 hours.
Rehabilitation After Knee Replacement
After surgery patients will stay in the hospital for a few days in order to undergo physical therapy to regain motion and strength in the new knee. Exercises focus on regaining knee flexion and extension range of motion. Patients are encouraged to put weight on the surgical leg as tolerated. They are given assistive devices like crutches or a walker for support during the initial recovery period. Most patients transition to using a cane once they can bear more weight safely. Formal physical therapy is continued after discharge at either an outpatient clinic or at home. It usually takes 4-6 months to recover strength and function in the replaced knee.
Outcomes and Longevity of Knee Replacements
The success rate of modern knee replacement surgery is very high. Over 90% of patients report significant relief from knee pain and improved mobility after the operation. With proper care and rehabilitation, most knee replacement prosthetics last 15-20 years before needing to be replaced again. This is called a revision surgery and it comes with increased risks compared to primary knee replacements. Advances in implant materials continue to improve the lifespan and restore patients’ ability to resume daily activities such as walking, climbing stairs, traveling and recreational activities. While the implants do eventually require replacement, knee replacement surgery remains a highly effective option for restoring function and relieving knee pain.
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it