Prosthetic implants composed of three parts that are made from metal alloys and durable polyethylene are used by orthopedic surgeons in knee replacement surgery to resurface damaged knee with artificial components. In a total knee replacement surgery, implants are used to replace the surface of the lower end of the femur, the top surface of the tibia and the back surface of the patella. For smooth motion and durability, the metals used in implant components are designed to border with special durable polyethylene.
As several manufacturers in the orthopedics field produce and advertise implants and there are currently over 150 designs available, choosing the best knee replacement is almost like buying a home that requires an in-depth research. It is natural to seek advice from others when making such decisions, however, their differing opinions may add to your dilemma.
The same holds true when choosing the best implant for knee replacement in Thailand – specialists may have differing opinions. This is why a comprehensive evaluation of several criteria beforehand is recommended. After all, the features of prosthetic implants play a pivotal role in the success of knee replacement surgery in Thailand or anywhere else in the world.
The surgeons generally base their selection of the brand and design of implants on the patient’s knee problem and anatomy; patient’s age, weight, level of physical activity and general health; their own experience and acquaintance with the device; and finally the price of knee replacement in Thailand.
The traits of an ideal knee replacement implant are as follows:
- Addresses the physical needs and medical conditions of the patient
- Facilitates normal activities and movements throughout the lifetime
- Has a long-term usage track record of at least 5 years
- Can be used comfortably by the surgeon because of his past experience with the particular implant
Knee replacement surgery in Thailand can cover most of these implant or prosthesis. If you need more information about a particular implant, it is best to consult your surgeon
Though the knee is generally regarded as a hinge joint as it functions like a hinged door, it is actually complex as its bone surfaces have to roll and glide for normal motion. Most of the implants are designed with the knee joint complexity in mind, generally trying to preserve the ligaments that support healthy knees. Some of the implants substitute ligaments to precisely facilitate the motion of a normal knee. While considering these mechanics it is also important to consider longevity, durability and the knee replacement price in Thailand.
Some of the most popular implant designs are discussed below.
The Anterior Cruciate Ligament (ACL) and the Posterior Cruciate Ligament (PCL) are completely removed in this design and PCL is substituted by implant components. It is the most commonly used implant design, however, the polyethylene part experiences more stress in Posterior-Stabilized Designs resulting in faster wear down.
The Posterior Cruciate Ligament (PCL) is retained in this implant design which is designed with grooves to accommodate PCL, whereas the Anterior Cruciate Ligament is removed as ACL may degenerate by itself in in severe osteoarthritis cases.
This design is ideal for the patients with a healthy posterior cruciate ligament that can stabilize the knee implant and participate in the roll sack mechanism of the knee after Total Knee Arthroplasty and control the joint line during the operation. Furthermore, it can reduce the bone cut, thereby preserving some for future revision TKA. Knee replacement surgery in Thailand for this procedure is certainly a destination of choice.
Both the anterior and posterior cruciate ligaments are retained in this design to make implants function as closely as normal knee joint functions. As bicruciate-retaining implant components are somewhat new to the market, its pros and cons are still under evaluation.
Provided the knee joint is partially damaged on one side only, unicompartmental implants, which are smaller than standard implants, can be used to resurface that particular side. Partial knee replacement can be more beneficial than total knee replacement if the knee damage is not severe and limited to just one side. Find out more about partial or total knee replacement in Thailand from your surgeon.
Types of Tibial Components
Most of the implants used in total knee replacement have a fixed-bearing design in which the tibial component is firmly attached to the metal component that lies beneath it. The femoral component that mimics the lower end of thigh bone rolls on this cushioned surface.
However, fixed-bearing implants wear down quickly if the patient is involved in an excessive activity or/and gains extra weight. As the worn out implant loosens from the bone surfaces, it can cause pain and failure of the implant. Fixed-bearing implants might be cheaper for some patients, which is why the knee replacement price in Thailand for this surgery must be considered.
Mobile-bearing designs need substantial support from the ligaments and other soft tissues as the tibial component can rotate short distances within the tibial tray which is made of metal. The artificial joint may dislocate and fail if the soft tissues cannot balance ligaments tension during the operation.
This design allows a few degrees greater medial and lateral rotation, and is recommended especially for younger, highly active and obese patients. Mobile-bearing implants are usually expensive than fixed-bearing implants and give the feeling of optimum mobility similar to that of the natural knee after the operation. Surgeons recommend this implant if possible to patients of knee replacement surgery in Thailand.
Generally, implants are put in place with polymethylmethacrylate which is fast-curing bone cement. However, implants can fits onto bone without cement as well. Cementless fixation uses implants that have a material that promotes the growth of new bone into the implant surface. Another implant fixation approach is hybrid in which the femoral component is press-fitted without cement while the tibial and patellar components are held in place with cement.
The surgeons select appropriate brand, design and components of the implant and choose the implant fixation method by thoroughly evaluating the patient’s situation. Patients are advised to talk to their doctor about their decisions and the reasons behind those decisions.