Knee replacement is a surgical procedure to replace the damaged knee joint with artificial prosthetic implants in patients with osteoarthritis or other knee diseases. The surgery is an effective and successful method to relieve pain and restore motion in the patients.
Knee replacement surgery in India is performed using high-quality implants to ensure that the patients receive the best treatment for their knee. if you are going for the surgery you must read the precautions of knee replacement.
There are several different types of knee implants available in India. The design and type of implant are recommended by the surgeon or hospital depending on multiple factors, including:
- The condition/damage in the knee joint
- The anatomy of the knee
- Age, weight and active lifestyle of the patient
- Surgeon’s experience and familiarity with the device
- The cost of the implant
The surgeon discusses the type of implant that will be used for your knee replacement surgery along with its pros and cons.
Knee replacement implants are usually made of metal alloys, ceramic, or medical-grade plastic parts. Three bone surfaces may be replaced in a total knee replacement procedure and there are three main components of a knee implant:
- Tibial component: It has two elements that are used to replace the top surface of the shin bone, known as the tibia. This part is made from a metal tray that is directly attached to the bone with a plastic spacer that provides a bearing surface. For more stability, the metal portion of the prosthetic part may have a stem that is inserted into the centre of the tibia bone.
- Femoral component: This prosthesis replaces the end part of the thigh bone, known as the femur. It is also used to replace the groove where the kneecap (patella) sits so that it glides smoothly against the bone. The metal femoral head curves around the bottom of the thigh bone.
- Patellar component: This component replaces the surface of the patella (knee cap), which protects the joint and rubs against the thigh bone. This component is the dome-shaped part made of plastic. The resurfaced patellar button allows it to slide smoothly over the front of the joint. This may or may not be resurfaced depending on the condition of the patient.
The types of implants are also categorized by the material used for their manufacturing. The material of the implants rub against each other the knee is flexed for movement.
Metal on plastic:
This is the most commonly used implant type. It consists of a metal femoral head that is mounted on a polyethylene plastic spacer which is attached to the tibial part. The metal alloys that are used for implants include cobalt-chromium, titanium, zirconium, and nickel.
This type is the least expensive amongst all types of implant. It also has the longest record for implant safety and lifespan. The one problem that can happen with this implant is an immune reaction might trigger due to the tiny particles that wear away from the plastic spacer. This can result in a break down of the bones, causing loosening or failure of the implant. Advances technology for manufacturing and processing material have significantly reduced the rate of wear in the plastic.
Ceramic on plastic:
In this type, a ceramic femoral component is used instead of the metal part (or a ceramic coated metal component). This is also mounted on a plastic spacer. It is especially considered for people who are sensitive to nickel element used in metal implants.
Ceramic on ceramic:
This type has both femoral and tibial components made of ceramic. The ceramic parts are the least likely to trigger an immune reaction in the body. The ceramic prostheses may make a squeaking noise while moving or walking. In some rare cases, they may shatter due to heavy pressure and surgery is performed to remove them from the body.
Metal on metal: This type of implants have femoral and tibial components made from metal. The metal implants are now being used less often because of concerns over particles of metal leaking into the bloodstream. The metal used for making the implants is processed by the chemical breakdown of the implant hardware. The metal implants were originally designed to last longer and used for joint replacements in younger patients. But the exposure to particles of metal in the blood can lead to inflammation, pain, and possible organ damage. The metal-on-metal type implants are considered mostly for young, active men as they are durable and may last longer while women of childbearing age do not receive these implants as it may affect the fetus.
The implant designs used nowadays recognize the complexity of a joint and can more closely mimic the motion of a normal knee. There are more than 150 designs for knee implants available in the market today. Some implants are designed to preserve the patient’s ligaments to maintain their function while others may act as a substitute for them.
The gender-specific implants are specifically developed with components for end of the thigh bone which more closely suits the anatomy of an average woman’s knee.
Currently, more advanced technologies are available such as custom 3-D fitted implants.
The following companies manufacture various kinds of knee implants for different types of surgeries, including total knee replacement (TKR), partial knee replacements (PKR), patellofemoral joint replacements (PFJ), revision knee replacements and others.
The type and quality of implant that will be used for the surgery is a major determinant for the overall cost of the knee replacement in India.
Some knee Implants that are commonly used in India are:
- NexGen LPS from Zimmer
- F.C. from Depuy Synthes (Johnson and Johnson)
- Oxinium implants from Smith and Nephew
- Vanguard from Biomet
- Scorpio NRG from Stryker