Medicare Part B covers knee replacement surgery when your doctor says it is medically necessary

Yes, Medicare Part B covers total knee replacement and partial knee replacement when a doctor determines the surgery is necessary to treat your condition. Medicare will pay for the surgeon's fees, the operating room, anesthesia, and the artificial knee joint itself. You pay your Part B deductible first (which varies by year), then Medicare pays 80 percent of the approved amount, and you pay the remaining 20 percent.

The key word is medically necessary. Medicare does not cover knee replacement for cosmetic reasons or to improve athletic performance. Your doctor must document that you have significant knee damage — usually from arthritis, injury, or wear — and that other treatments have not worked or are not appropriate for you.

The surgery itself is typically done in a hospital outpatient department or an ambulatory surgery center. Hospital stays for knee replacement are usually one day or less, though some people stay overnight. If you stay overnight, your costs change because you would use your Part A hospital benefit instead of Part B.

Key Takeaways

  • Medicare Part B covers the surgeon, operating room, anesthesia, and the artificial joint when your doctor says knee replacement is medically necessary.
  • You pay your Part B deductible first, then 20 percent of the approved cost; Medicare pays the other 80 percent.
  • Your doctor must document that you have significant knee damage and that other treatments have not worked before Medicare will cover the surgery.
  • Physical therapy after surgery is covered by Medicare Part B when ordered by your doctor, though you still pay 20 percent after your deductible.
  • If you have a Medigap or Medicare Advantage plan, your out-of-pocket costs may be lower than the standard 20 percent.

What Medicare Part B actually pays for

Medicare Part B covers the full surgical procedure, which includes the surgeon's fee, the operating room rental, anesthesia, and the prosthetic knee joint. It also covers pre-surgery tests like X-rays and blood work that your surgeon orders before the operation. Post-surgery imaging — such as X-rays to check how the new joint is healing — is covered when medically necessary.

The artificial knee itself is considered part of the surgical procedure, so there is no separate charge for the implant. You do not get to choose between different brands of knee joints and pay more for a premium option; Medicare covers one standard prosthetic knee, and that is what your surgeon will use unless you choose to pay out of pocket for an upgrade.

Hospital stays for the surgery are covered under Part B if you have outpatient surgery, or under Part A if you are admitted overnight. Most knee replacements are now done as outpatient procedures, meaning you go home the same day or the next morning.

Physical therapy and rehabilitation after surgery

Medicare Part B covers physical therapy ordered by your surgeon after knee replacement surgery. This is crucial: without therapy, your new knee will not work well, and therapy is where most of the recovery happens. You typically start therapy within days of surgery, either at home with a visiting therapist or at an outpatient clinic.

Medicare covers up to 36 visits per year for physical therapy, though your surgeon will likely order fewer visits than that. You pay 20 percent of the approved cost for each visit after you have met your Part B deductible. If you have already met your deductible for the year from the surgery itself, therapy visits cost you 20 percent with no additional deductible.

Occupational therapy — which helps you relearn daily tasks like getting in and out of a car or climbing stairs — is also covered when your doctor orders it. Some people need both physical and occupational therapy in the weeks after surgery.

How much you will pay out of pocket

Your costs depend on whether you have already met your Part B deductible for the year. The Part B deductible changes annually; you can find the current year's amount on Medicare.gov. Once you meet the deductible, you pay 20 percent of Medicare's approved amount for the surgery and all related care.

If you have a Medigap policy (supplemental insurance), it may pay some or all of your 20 percent coinsurance, depending on which plan you have. Plans G, F, and N typically cover a large portion of your out-of-pocket costs. If you have a Medicare Advantage plan, your costs may be different; some Advantage plans have copays instead of coinsurance, and your out-of-pocket maximum is capped by law.

Costs also depend on whether your surgeon and hospital are in-network with Medicare. Medicare-participating providers have agreed to accept Medicare's approved amount as payment in full. If your surgeon does not participate in Medicare, you could owe more.

What Medicare does not cover

Medicare does not cover knee replacement if your doctor determines it is not medically necessary. For example, if you have mild arthritis and pain but can still walk and function, Medicare may not cover surgery. The decision rests with your doctor and Medicare's medical review process.

Medicare also does not cover revision surgery (replacing a knee that was already replaced) in the same way as a first replacement, though it may still cover it if medically necessary. Ask your surgeon whether your specific situation qualifies.

Any upgrades to the standard prosthetic knee — such as a more advanced or custom-designed joint — are your responsibility to pay for if you choose them. Your surgeon can tell you the cost of an upgrade before surgery so you can decide whether to proceed.

Getting approval before surgery

You do not need to get permission from Medicare before having knee replacement surgery. Your doctor decides whether it is medically necessary, and Medicare trusts that decision. However, it is wise to ask your doctor's office to verify that Medicare will cover your surgery before you schedule it.

Your surgeon's office can submit your medical records to Medicare for a coverage information if there is any question about whether your condition qualifies. This takes a few days but gives you certainty before you commit to surgery. If Medicare denies coverage, you have the right to appeal.

If you have a Medicare Advantage plan instead of Original Medicare, the rules are the same — the plan must cover medically necessary knee replacement — but you should call your plan's customer service line to confirm your out-of-pocket costs before surgery.

Frequently Asked Questions

Do I need to try other treatments before Medicare will cover knee replacement?

Medicare does not have a strict rule requiring you to try other treatments first, but your doctor must document that surgery is medically necessary for your condition. In practice, most people have tried physical therapy, injections, or medication before surgery. Your doctor will explain what evidence supports surgery in your case.

Will Medicare cover a knee replacement on both knees at the same time?

Yes, if both knees need replacement and your doctor says it is medically necessary, Medicare will cover both surgeries. However, most surgeons recommend doing one knee at a time so you can recover and regain strength before the second surgery. Ask your surgeon about the risks and benefits of doing both at once.

What happens if I choose a more expensive artificial knee?

Medicare covers one standard prosthetic knee. If you want a more advanced or custom knee joint, you pay the difference between the standard knee and the one you choose. Your surgeon's office can tell you the upgrade cost before surgery so you can decide whether to pay for it.

Does Medicare cover knee replacement at any hospital or surgery center?

Medicare covers knee replacement at any hospital or ambulatory surgery center that participates in Medicare. Most do. If your surgeon uses a facility that does not participate in Medicare, you may owe more. Ask your surgeon's office whether the facility is Medicare-participating before you schedule surgery.

Will my Medicare Advantage plan cover knee replacement the same way?

Yes, Medicare Advantage plans must cover medically necessary knee replacement. However, your out-of-pocket costs may be different — you might have a copay instead of coinsurance, and your costs are capped at an annual maximum. Call your plan to find out your specific costs before surgery.