Depending on the Medicare Supplement plan that you choose, it might cover some cost of a knee replacement surgery. These plans assist with deductibles, coinsurance or copayments. Be sure to note that your prescription drugs are not covered by Medicare or a Medicare Supplement. You will need to consider a Prescription Drug Plan to cover the out-of-pocket cost. Our advisors can walk you through that entire process and answer any questions you have, FREE of charge.