Knee replacement surgery is recommended for knee pain or limited knee functioning. There are three types of material used for knee implants, including metal, plastic, and ceramic; you and your surgeon will make the choice of which to use. After knee surgery, the goal is to resume normal functioning; thus, your surgeon may assign a home healthcare worker to assist in this process.
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Knee pain and poor functioning are indications of knee replacement surgery.
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Knee replacement surgery involves the surgeon clearing the damaged bone and cartilage, then placing it in an artificial implant.
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The implants can be made of metal, polyethylene (plastic), or ceramic, with the metal ones being the most durable and long-lasting.
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After surgery, clicking and popping noises are normal; they are concerning if associated with pain and swelling.
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A home health care assistant may be needed at your home to help with the activities of daily living.
What is knee replacement surgery?
Knee replacement surgery involves the surgeon clearing out the damaged bone and cartilage, then replacing it with an artificial solid implant (different types to be discussed later).
The surgery is considered if there is pain or decreased function, such as the inability to walk or climb stairs, and conservative treatments have not worked.
What are the knee structures involved with knee replacement surgery?
As you can see from diagram 1, the knee is made up of three main bones: the femur (thigh bone), the tibia (shin bone), and the patella (kneecap). The medial and lateral meniscus are thick fibrocartilage that cushions the femur and tibia. Also shown is the articular cartilage of the femur.
What exactly is surgically performed in knee replacement surgery?
As you can see in diagram 2 above, there are three different pictures. The picture on the far left shows a diseased knee with damaged cartilage and a narrowed joint space. The middle image demonstrates the knee's appearance after the surgeon removes the damaged cartilage and bone. Finally, the image on the far right shows the knee after surgery, with replacement implants.
What material is used for the artificial replacement parts?
Understanding the materials used for replacement implants (parts) can be the most confusing of the process. However, we will explain it in straightforward terms.
As seen in diagram 3, the replacement implant has four parts: the femoral component, the tibial component, the polyethylene (plastic) liner, and a kneecap (patellar) component.
The tibial component can be made of metal (titanium or chromium-cobalt) or ceramic material, while the femoral component can be made of metal, ceramic, or plastic. The plastic liner performs like cartilage, allowing for smooth motion.
The implant in diagram 3 is a metal-on-metal type with a plastic spacer.
FAQ
Can there be a reaction to the implant?
Although rare, some people can have an allergic (immune) reaction to metal or plastic implants. In these cases, the implant needs to be surgically removed and replaced. Unfortunately, no preoperative (before surgery) test is available to predict the likelihood of a reaction to metal or plastic.
Can the replacement implant wear out?
Polyethylene (plastic) implants can undergo wear and tear changes leading to a needed replacement. However, there has been much quality improvement in polyethylene over the past 30 years.
Metal knee implants are much less likely to wear out, so metal on metal are the implants of choice for younger people who are more active.
What kind of implant should you choose?
Given the different types of implants, adverse reactions, and durability, we know the choice can be difficult. The best advice we can give is to review all the options with your surgeon since every case is different. While one implant may be best for one person, it may not be best for someone else. In this article, we are supplying information to help you decide.
What can you expect when you get home after knee replacement surgery?
There are everyday tasks called activities of daily living (ADL); they include getting in and out of bed, bathing (showering), eating, walking, and going to the bathroom.
After knee replacement surgery, you may have difficulty performing these tasks. Therefore, your surgeon may arrange for a temporary caretaker for assistance.
Are all knee replacement surgeries total knee replacements?
If only one side of that knee is affected, usually the inner side, a partial knee replacement surgery can be done. However, these partial replacement surgeries make people more likely to need surgical revision.
In addition, even though there is less clearing of the bones and cartilage and less hardware, the surgery can sometimes be more complicated since the surgeon operates in a smaller space.
What are some typical symptoms seen after surgery?
After the surgery, you may hear clicking and popping sounds with knee bending, usually due to the tendons adjusting to the metal, plastic, or ceramic parts. In most cases, the sounds go away in a few months; however, if the popping is associated with pain or swelling, it could be concerning.
What happens after the surgery?
Most people will need to stay in the hospital for anywhere from 1 to 4 days. Once discharged, wound care is very important; your doctor may have someone visit your home to check the wound.
Since it is crucial to avoid falling, you may be given crutches, a walker, or a wheelchair. In addition, your doctor may arrange for a physical therapist to come to your house for supervised walking and to assist in exercises to strengthen the supporting muscles.
- National Library of Medicine. Allergy in Total Knee Replacement.
- National Library of Medicine. Total Knee Replacement.
- Mayo Clinic. Knee Replacement.
- Versus Arthritis. Knee Replacement Surgery.
- National Library of Medicine. Plastics in Total Knee Replacement.
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