There are two different types of knee replacement procedures your surgeon may recommend to relieve your knee pain. One is partial knee replacement, also called unicompartmental replacement, and one is total knee replacement. Learning the differences can help you have a better discussion with your surgeon.
Whether it’s partial or total, knee replacement surgery does not really “replace” the knee. Only the ends of the bones that make up the knee, called the articular surfaces, are replaced. The new joint works the way cartilage works in a healthy knee by preventing the bones of the leg from rubbing together at the joint.
The synthetic joint can be made of highly polished metal, durable plastic, even ceramic material. There are many different types on the market today. Speak to your surgeon about the joint that would be best for you.
Understanding the Knee
To understand knee replacement surgeries, it helps to know a little about the knee. The knee is made up of three bones: the femur is the longest and strongest bone in your body; the tibia, or shin bone; and the patella, or kneecap. When these bones come together, they form three distinct areas, or compartments:
- Medial compartment (inner)
- Lateral compartment (outer)
- Patellofemoral compartment (kneecap)
Partial or Unicompartmental Knee Replacement
X-ray and MRI (Magnetic Resonance Imaging) results may tell your surgeon which compartments of your knee are damaged. If your knee damage is in either the medial or lateral compartment and nowhere else, your surgeon may decide a partial knee replacement is right for you.
Because only part of the knee is being “replaced,” a small incision will be made, and only the ends of the bones that are damaged will be replaced with the synthetic joint or “uni.”
Total Knee Replacement
In this procedure, your surgeon makes an incision in order to replace the damaged ends of all three bones in the knee and the damaged cartilage with the synthetic joint.
[1] http://orthoinfo.aaos.org/fact/thr_report.cfm? Thread_ID=513&topcategory=Knee
