Does Medicare cover knee replacement surgery?

Medicare covers surgery that is medically necessary, meaning you need it to treat a health problem. For knee replacement, the regional companies that handle Medicare claims spell out what that means. One of them, Novitas Solutions, covers a total knee replacement when at least three of these are true:

• An X-ray or MRI shows advanced joint damage, like worn cartilage, bone spurs, or a narrowed joint space.
• Other treatment did not work, and your record says so. This is usually 3 months or more of things like pain medicine and physical therapy exercises.
• Knee pain limits your daily life, even after you followed the treatment plan.
• You have a specific problem in the bone, like a break near the knee, a tumor, or bone that has died from poor blood flow.
• A past knee replacement has failed, for example from loosening, a break, or infection.

Other regions have their own rules for this surgery. The pattern is the same: your doctor's notes must show the damage and what you already tried.

In short: Medicare pays when the record shows real joint damage, real limits on your life, and treatment that failed.

You are an inpatient only if a doctor writes an order to admit you to the hospital. If you stay overnight without that order, you may still be an outpatient, often called observation. Ask the hospital which one you are.

• Inpatient: Part A pays the hospital stay. Part B pays the surgeon and other doctors.
• Outpatient: Part B pays it all, including same-day surgery in a hospital outpatient department.

This also affects rehab. Medicare covers a stay in a skilled nursing facility only after an inpatient hospital stay of at least 3 days in a row. The day you leave does not count, and observation time does not count.

If you are admitted as an inpatient: you pay the $1,736 Part A deductible for each benefit period in 2026. After that, days 1 to 60 cost $0. For the surgeon and other doctors, Part B pays 80% of the approved amount, and you pay 20% after the $283 Part B deductible.

If the surgery is outpatient: you pay 20% of the approved amount for the surgeon after the $283 Part B deductible. You also pay the hospital a copayment for each service. In most cases, that copayment cannot be more than the Part A deductible for each service.

Medicare does not publish one price for knee replacement. To see national average costs, use Medicare's Procedure Price Lookup tool, or ask the surgeon and hospital for an estimate.

• If you have a Medigap plan: it can help pay your share of Part A and Part B costs, like the deductible and the 20%.
• If you have Medicare Advantage: your plan sets its own copays, which may start on day 1 of a hospital stay. Check your plan's Evidence of Coverage.
• If you have Medicaid too: Medicaid may pay your share. Ask your state Medicaid office.

After surgery, your doctor may order therapy to help you walk and bend the knee. Medicare covers it in several places:

• A skilled nursing facility, after a 3-day inpatient stay. In 2026, days 1 to 20 cost $0. Days 21 to 100 cost $217 a day.
• Outpatient physical therapy under Part B, at 20% of the approved amount. See Does Medicare cover physical therapy?

1. Work with your doctor on other treatment first. Medicine, exercises, and physical therapy, written down in your record, are part of what Medicare looks for.
2. Get imaging. An X-ray or MRI that shows the joint damage supports the claim.
3. Choose a surgeon and hospital that take Medicare. You can search for them on Medicare.gov.
4. Ask if you will be an inpatient or an outpatient. Then ask for a cost estimate for that setting, including rehab.
5. Plan your rehab before surgery. If you will need a nursing facility, ask whether you will meet the 3-day inpatient rule.
6. If Medicare says no, appeal. Your Medicare Summary Notice explains how. Ask your surgeon for a letter that covers each reason the surgery is needed.

In short: build the record, confirm your inpatient or outpatient status, and plan rehab before the surgery date.