Knee Replacement - How is a knee replaced?

How Is a Knee Replaced With an Artificial Knee?

Although each procedure varies, generally, surgery to replace a knee usually lasts about two hours. After the damaged bone and cartilage of the knee is removed, the orthopaedic surgeon will place the new, artificial knee in its place.

The two most common types of artificial knee prosthesis used in replacement surgeries are cemented prosthesis and uncemented prosthesis. Sometime, a combination of the two types is used to replace a knee. A knee prosthesis is made up of metal and plastic. A cemented prosthesis is attached to the bone with a type of epoxy. An uncemented prosthesis attaches to the bone with a fine mesh of holes on the surface, in order for the bone to grow into the mesh and attach naturally to the prosthesis.

The prosthesis (artificial knee) is comprised of the following three components:

• Tibial component (to replace the top of the tibia, or shin bone)
• Femoral component (to replace the two femoral [thighbone] condyles and the patella groove)
• Patellar component (to replace the bottom surface of the kneecap that rubs against the thighbone)

While undergoing surgery, the patient may be under general anesthesia or awake with spinal or epidural anesthesia.