Articular c artilage is a very slippery coating that covers the bones in the knee joint. This cartilage is ten times more slippery than ice and it allows the bones to slide over each other as they move.
With age or after an injury, the cartilage may become worn or frayed. This loose, worn tissue breaks up the smooth surface and causes the joints to rub together instead of sliding. The rubbing can cause pain and swelling in the joint.
During arthroscopic surgery, these frayed areas can be seen. Chondroplasty is the smoothing down of this frayed material. Although this will not return the cartilage to normal, removing the damaged tissue allows the remaining cartilage surfaces to slide more easily over each other and will decrease the pain.
On the left can be seen a knee with healthy cartilage. Notice the smooth white surfaces. This is the cartilage covering the bones.
The image on the right shows a knee with damaged cartilage.
Notice that the cartilage covering the upper bone is no longer smooth but instead looks rough and shaggy. This rough surface is no longer able to slide smoothly over the cartilage below it causing pain.
During chondroplasty, the rough surface of the cartilage is shaved down to make it smoother. Although it cannot be restored to a perfectly smooth surface, decreasing the roughness of the surface decreases pain and improves function of the joint.