What is knee replacement surgery? Actually, the term knee replacement is somewhat of a misconception. Knee replacement should be called knee resurfacing. Knee resurfacing is putting new coverings over the ends of your bone to replace worn or damaged cartilage. Your new cartilage is in the form of a plastic. This is an example of a knee replacement. Here is your thigh bone and your shin bone. This is your kneecap out in front. The metal coverings that you see are actually the knee replacement implants. As you can see, they resurface the end of your thigh bone, they resurface the top of your shinbone, and then this plastic is your new cartilage in between.
If you’ll notice your ligaments remain except for perhaps one, the anterior cruciate ligament, or in some cases both the anterior and posterior cruciate ligament. Your stability comes from the ligaments on the side of your knee. In fact after knee replacement surgery you can sprain your knee or twist your knee because you still have your ligaments. The kneecap is out in front because the end of your thigh bone is now made of metal. Often we will put a plastic button on the back of your kneecap or patella. Now you can see that the plastic button moves back and forth very smoothly after knee replacement surgery. Also notice how straight the knee is. When your knee is arthritic, often one side of the knee is without cartilage and the bones may be touching. This may cause your knee to curve following knee replacement surgery and once the new coverings and new cartilage had been placed in your knee, the knee would be back to its normal alignment.
Following knee replacement surgery, patient’s goal is the bend the knee as far as possible. The stitches are put in with the knee flexed to one hundred and thirty degrees. The implant itself can bend very far. The goal after surgery is to get that bend back. Patients who get the range of motion back in their knee that they desire after knee replacement are the happiest knee replacements we have.