What is Total Knee Replacement?
Total Knee Replacement was first performed in the year 1968 and it remains one of the most important orthopaedic surgical advances of this century. Recent innovations in implant materials and advances in surgical techniques have made this surgery very successful and popular. Close to 40,000 Total Knee Replacement surgeries are done annually in India and this number keeps on increasing every year.
The main reason for replacing any degenerative joint with an artificial joint is to stop the bones from rubbing against each other. This rubbing causes pain. Replacing the painful and degenerative joint with an artificial joint gives the joint a new surface, which moves smoothly without causing pain. The goal is to help people return to many of their activities with less pain and with greater freedom of movement.
There are various types of Knee Prosthesis and the choice of the appropriate one is based on the condition of the Knee, age and lifestyle of the patient.
Each type of Artificial Knee Joint is essentially made up of three parts:
The Femoral component (top portion) replaces the worn out cartilage of the Femur (Thigh Bone).
The Femoral components made of metal.
The Tibial components usually made of two parts: a metal tray that is attached directly to the bone, and a plastic spacer that provides the slick surface.
The Tibial component (bottom portion) which consists of tibial base plate and tibial insert replaces the worn out cartilage of the tibia (Leg Bone).
The Patella Component (Kneecap portion) replaces the worn out cartilage of the Patella.
The Patellar components is made of plastic.
The prosthesis is held in place by a type of epoxy cement that attaches the metal to the bone.
Scientists, orthopaedic surgeons and implant manufacturers continuously strive to improve the durability of this prosthesis. Current innovations have resulted in the use of titanium and cobalt-chrome alloys, which are used for femoral and tibial implants, and low friction plastic component, made of ultra-high molecular weight polyethylene polymer, which acts as a spacer and articulating surface between two metal components.
All materials used in moving surfaces are very durable, but they will eventually wear out. This is as true in surfaces of artificial joint implants as in those of car tyres.