What is the role of knee implants in a knee replacement surgery?
Do you feel constant pain in your joints? Everyday routine adversely affected by poor mobility? Do you find yourself struggling to achieve your daily goals? Depending on the condition and pain level of your knees,medications and therapies can be your best recourse.However, when these options fail, a partial or a total knee replacement surgery is recommended.
Knee replacements are operative substitutions of a knee joint, where the femur and tibia bone meet with an artificial joint or implants. The procedure facilitates the knee to move properly, alleviating pain from joint trauma,rheumatoid arthritis, or degenerative diseases like osteoarthritis consequentlyhelping in leading a better quality life.
When is it the right time to opt for a knee replacement surgery?
- Are you experiencing intense knee pain or tautnessthereby preventingyou from carrying out dailychores? For instance, walking, climbing upstairs, standing up after sitting, etc.
- Do you feel moderate, but incessant knee pain that is persistent even while resting or sleeping?
- Have you sensed chronic knee inflammation and swelling despite medications or therapies?
- Do you see any knee deformity?
Knee’s condition and physical activity play an important role in deciding thetype of implant
Fixed bearing: Most patients receive a fixed implant. It is not as strong and has less mobility when compared to the other implant, but is best suited for patients who are not overweight and do not lead an active lifestyle. An ideal recommendation for this composition is generally elderly patients who will not put serious wear-and-tear on the implant and are unlikely to require a revision. This is because a metal implant is attached to the tibia and a polyethylene component is attached atop it, forming a cushioned surface.
Mobile bearing: This design lets the plastic cushion of the tibial component to rotate to some degree, giving patients more flexibility on the medial (inner) and lateral (outer) sides of the knee. These are best suited for young and active lifestyle patients.It ideally is known to reduce the risk of dislocation.
Different materials used for implants and their purposes
Metal on plastic: This is the commonest type of implant. It features a metal femoral component that sits on a polyethylene plastic spacer attached to the tibial component. Metals frequently used include cobalt-chromium, titanium, zirconium, and nickel. It is inexpensive and has the record of being safe. Nevertheless, with plastic implants, an immune reaction can be actuated by tiny particles that wear away from the spacer leading to bone breakdown, loosening, and failure of the implant.
Ceramic on plastic: This type uses a ceramic femoral component instead of metal or a metal component with a ceramic coating and rides on a plastic spacer. It is best used on patients that show sensitivity towards the use of nickel, though; plastic particles can lead to an immune reaction.
Ceramic on ceramic: The femoral and tibial components are both made of ceramic thus helping circumvent any reactions with the body. Conversely, they can break under heavy pressure into pieces leading to surgery to remove them.
Metal on metal: The femoral and tibial components are both made of metal. Since metal may lead to traces in the bloodstream, they are not as popular. These can cause inflammation, pain, and probably even organ damage therefore they are better used for younger and active patients preferably men since they last longer.
Does the material match the following criteria?
- All materials must be biocompatible, which is to say, they can be laid in the body without creating a rejection.
- Their strength and shape should be retained for a long-term.
- They should be capable of duplicating the knee structures they are proposed to replace. For instance, strong enough to take weight, flexible to bear stress without breaking, and the ability to move smoothly against each other as and when required.
Understanding the three components of a knee implant
Patellar component – This piece is dome-shaped to go with the resurfaced shape of the patella. Since the patella rests against the femur, the alignment of the patellar component along with the femoral component is fundamental for proper functioning.
Femoral component– This piece fastens to the end of the femur. It has a groove that permits the patellar component to move smoothly up and down smoothly as the knee bends and straightens.
Tibial component -This part is fastened to the tibia for stability and is a flat metal platform with a cushion of strong and durable plastic.
No matter what implant the doctor chooses, they all have to offer the same basic function — substituting your unhealthy bone and reducing your pain.Your age, weight, anatomy, and activity level will help the surgeon in picking the right prosthetic device. In the end, implant designs are made in recognition of the complexity of the joint and more strictly to mimic the motion of a regular knee to lead a normal life.