Are you thinking of knee replacement surgery? Fundamentally, the concept behind a knee replacement surgery is to remove and replace a worn-out, arthritic joint with the artificial knee implant. Apart from your general health and commitments, the type of knee implant is an important factor worth discussing with your knee surgeon.
It’s easy to get confused as many manufacturers sell knee implant components made of metal on plastic, ceramic on plastic, and more. This makes it crucial to understand which implant is right for your case and how it can be useful in pain relief and inflammation reduction.
This article will walk you through several implant options that you can discuss with your surgeon for the best chances of success and recovery.
Types of Implants for Knee Replacement Surgery
While there are several types of knee implants, all of them have some things in common.
Firstly, all implants comprise an element which attaches one of the two bones of the lower leg to the thighbone and one that attaches to the tibia. An implant may or may not have a patellar component that functions precisely like the kneecap.
Secondly, all knee implants are made of bio-compatible content and made relatively lightweight (usually range from 15 to 20 ounces) to adhere to the bone with ease.
1. Fixed-Bearing Implant
A fixed-bearing implant is commonly used for knee replacement surgery. Studies indicate that 95% of fixed-bearing implants still perform well after 10 years of use if used properly. However, they are not as strong as other implants and are primarily suitable for underweight, non-active patients.
Applying too much friction causes the polyethylene component to break and increases the chances of loosening the implant, leading to implant failure.
2. Mobile Implant
For young and active patients, mobile-bearing implants function well and provide flexibility even in the deep knee bends. The mobile-bearing design allows the plastic cushion of the tibial part to rotate on the medial (inner) and the lateral (outer) knee sides, giving patients more mobility.
The polyethylene part is designed to adjust to the metal tibial tray in a way that permits small rotation. The design was developed to reduce the wear of polyethylene in fixed-bearing designs. This creates less friction between the components and would ideally reduce the probability of loosening the implant.
Research suggests that mobile-bearing knee implants have a 95% success rate 10 years after implantation.
3. Medial Pivot Implant
The architecture of the medial pivot implant has a mobile-bearing that imitates the movement of the knee. It rotates, turns, and bends the same way as a natural knee joint. This implant is more complicated than fixed or standard bearing designs; thus, it comes at a higher cost.
The components of a media pivot implant are based on a “ball-and-sock” system rather than a “hinge joint” approach used for more traditional knee replacements.
It appears to be stronger than other designs of the implant—98.8% of medial pivot implants lasted for at least 17 years. Since it allows a wide range of contacts between components, it decreases wear and tear and increases implant life expectancy.
4. Gender-Specific Implants
Making a “one-size-fits-all” solution is impractical for knee replacement surgery. Gender-specific implants take into consideration the differences between male and female body frames.
Knee replacement surgeons have identified anatomic variations between men and women. In a female’s anatomy, the end of the bone femur has a little different outline.
According to statistics, women opt for a knee replacement more than men, which accounts for approximately two-thirds of all knee replacement surgeries.
5. Total and Partial Knee Implants
In some cases, a patient needs a bilateral knee replacement, which means surgery on both knees. The surgeon may carry out both operations concurrently or can opt to use a staged bilateral approach, which is done after several days, weeks, or months after the first surgery.
After a full medical assessment is done, the option between total and partial knee replacement is based on a recommendation from a doctor.
- Total Knee Replacement:
Total knee replacement covers the medial, lateral, and front compartments of the knee joint. In this surgery, the entire joint compartment is replaced, i.e. the femur, tibia, and patella.
Depending on the nature of the chosen implant, the ligaments supporting the knee are left in place or removed. A plastic cushion replaces any present cartilage between the femur and tibia.
- Partial Knee Replacement:
Partial knee replacement is also known as knee resurfacing. It entails either the inside (medial) or outside (lateral) compartments of the knee joint. Essentially, only the damaged parts of the knee joint are removed in this process.
Partial knee surgery may also require osteotomy to reduce a specific weight of the injured part of the knee. Here, the surgeon removes or attaches a wedge of the bone to a tibia or femur.
Which Material Is Used in Knee Implants?
Artificial knee implants are typically made of titanium or cobalt-chromium based alloys because these metals are durable, versatile, and they also neither corrode nor react with the body. They can also be made from full metal or mixed with plastic or ceramic.
Cobalt-Chromium:
It is a durable metal typically used in the femoral component because there is a large amount of friction in the femoral part, for which the best choice of material is cobalt chromium.
Those with allergies to nickel must, however, avoid this substance because it can cause a reaction; instead, they can use a mixture of ceramic and zirconium alloy.
Titanium-Cobalt:
This material is an elastic, flexible metal that protects the implant’s natural bone. It is typically used in the plastic insert tibial section.
Your surgeon will discuss with you the material that will be used for you considering your activity levels, weight, allergies, and age. Consult the experts at CK Birla Hospital for any questions related to .
Bottom Line
Ultimately, it’s important to work with your doctor for a fair period of time to select the best implant considering your current state. Rely on your surgeon to explore your options and work together to assess your particular needs for the highest rate of success.
