Hello, I’m Dr. Bill Bryan, orthopedic surgeon.
I have in my hands a typical total knee replacement. Let’s go over some of the basic features.
This is the femur, the thigh bone, and the femoral component which is made either of
chrome-cobalt steel or ceramic. It’s fitted over the end of the femur after the surgeon
makes very precise cuts on the bone. First, we put in trials and from those trials
we pick the shape and size that’s best for you. On the tibial side the bone is very precisely
cut. A metal tray, which is generally made of titanium, is either cemented or held to
the tibia with roughen surface. This tray then holds the so-called tibial insert. It’s
a convex polyethylene material, which is extremely durable and made to precisely fit the contours
of the convex femoral component. This model does not show what happens to the
patella. The patella, the kneecap, is in front of the knee joint and at surgery the surgeon
will flip that over, remove the roughen back surface and cement a plastic button which
will then ride against the metal. The result of all this is that your body is not going
to feel the load and the motion of the knee joint, because the nerve endings are now protected
with the metal and plastic that has been inserted.