Question: What is (are) Knee Replacement ?
Answer: Knee replacement may be either total or partial/unicompartmental. In total knee replacement, as the name suggests, the entire knee joint is replaced. You will likely need a total knee replacement if you have damage to several parts of your knee. In partial/unicompartmental knee replacement, the surgeon replaces just the damaged part of the knee. You may be able to have a partial knee replacement if only one section of your knee is damaged. However, when one part is replaced, there is a chance that another part will develop arthritis, requiring further surgery.
Source: NIHSeniorHealth