Total knee prosthesis
- Replacement of worn surfaces
- Metal surface on the femur
- Plastic surface supported by a metal tray on the tibia
- Plastic button on the surface of the patella
- Cemented or uncemented
The goal of total knee replacement is to remove the worn surfaces of the arthritic joint and replace them with new, artificial surfaces. In the case of a total knee, the artificial femoral surface is made of a metal alloy (cobalt, chrome and molybdenum). The tibial surface is replaced with a metal tray supporting a polyethylene plastic spacer. The patella surface is more often than not resurfaced with a plastic button. Some surgeons choose not to replace the patellar surface. The issue is controversial and there is no definitive answer whether to replace the patella surface or not. I do replace the kneecap surface in all cases.
The prosthesis is attached to the bone with help of bone cement, or in some designs without cement. The uncemented prosthesis initially relies on tight fit. Later on, the bone will grow into the porous surface of the prosthesis and form a biological bond. In my practice, I exclusively use the cemented total knees.