Knee replacement surgery is the most common procedure which is performed around the globe to relieve patients from knee pain and other conditions related to it. The statistics related to it are alarmingly high, with over 500,000 replacements occurring every year in the USA alone. The number of knee replacement cases is expected to touch around 3 million by the year 2030. These knee replacement surgeries involve the use of implants manufactured by various companies which are used to replace the natural joint. These implants are generally made of metal and plastic. Now the question arises as to which implants are best? For finding an answer to this question, we have to take a look at some facts.
The Structure of a Natural Knee
The natural joint constitutes of three parts-
- Medial compartments
It refers to the inner side of the knee.
- The lateral compartment
It consists of the outer side of the knee.
- Patello-femoral compartment
It consists of the part underneath the knee cap.
A total knee replacement means the replacement of all the three compartments of the knee. Partial knee replacements mean that only one compartment is replaced.
Four artificial components compose a total knee replacement implant: a tibial component, femoral component, patellar component, and a plastic spacer.
A Look at the Components of Implants –
Tibial component— it refers to the flat part that attaches to the top of the tibia or the shin bone at the front of the leg. This part is usually manufactured with a metal platform with a polyethylene (plastic) insert. A soft metal, like titanium alloy, is used for the metallic part
Femoral component— It refers to the curved part that attaches to the femur or the thighbone. This part is made of metal or ceramic. Cobalt-chromium alloys are commonly used for this part.
Patellar component— It refers to a dome-shaped piece that is used to replace the knee cap. This part is made of polyethylene, which is a durable kind of plastic. It is used in some cases only.
Plastic Spacer— The plastic spacer is used between the tibial and femoral components. It is also made of plastic (polyethylene). Plastic spacer provides free motion and flexibility by giving the knees a smooth, gliding surface.
What Constitutes a Good Knee Implant?
You will have different answers to this question, according to the person asked. The criteria for a good implant may vary and so may the answer. The benchmark varies from satisfactory performance to long term results. Ideally speaking, the following points should be covered by a good implant material-
- Allow normal movement and activities after the surgery
- It should last for at least 15-20 years
- Should be able to meet your specific requirements (these include your condition, compatibility with the material used, etc.)
- The Surgeon must be be known to be performing knee replacement surgeries for at least 5-10 years.
- The surgeon must be familiar with the brand and the style.