Medicare Part B covers knee replacement surgery, but you pay a share of the cost

Medicare Part B covers knee replacement (also called total knee arthroplasty) when your doctor determines it is medically necessary. You will not pay the full cost — Medicare pays its portion directly to the hospital or surgical center — but you are responsible for your deductible, coinsurance, and any costs that fall outside what Medicare considers reasonable.

The surgery itself is covered as an inpatient procedure at a hospital or outpatient procedure at a surgical center. Physical therapy after surgery is also covered, though it has its own rules. The key is that your doctor must document that the knee replacement is necessary to treat a condition like severe arthritis, and not cosmetic or elective.

Key Takeaways

  • Medicare Part B covers the surgeon's fee, anesthesia, and facility costs for knee replacement when medically necessary, but you pay the Part B deductible ($240 in 2024) plus 20% coinsurance.
  • You must meet the Part B deductible before Medicare begins paying its share, and coinsurance continues for the full hospital stay or outpatient visit.
  • Post-operative physical therapy is covered under Part B, but limited to a set number of visits per year unless your doctor documents medical necessity for more.
  • If you have a Medigap or Medicare Advantage plan, your out-of-pocket costs may be lower because those plans cover some or all of the deductible and coinsurance.
  • Knee replacement is not covered if your doctor considers it elective, cosmetic, or not medically necessary for a documented condition.

What you pay out of pocket for knee replacement

Your costs depend on whether you have Original Medicare alone or a supplemental plan. With Original Medicare (Part A and Part B), you pay the Part B deductible ($240 in 2024, though this amount changes yearly) before Medicare pays anything. After you meet the deductible, you pay 20% coinsurance on the surgeon's fee and related services.

If the surgery is inpatient (you stay overnight), you also owe the Part A hospital deductible ($1,632 in 2024 for each benefit period). If it is outpatient, you only owe the Part B deductible and coinsurance. The total out-of-pocket cost varies widely depending on the surgeon's fee, the facility, and your location — but typically ranges from $1,500 to $6,000 or more with Original Medicare alone.

If you have a Medigap plan (supplemental insurance), it may cover your deductible and coinsurance, reducing your out-of-pocket cost to zero or close to it. If you have a Medicare Advantage plan, your costs depend on that plan's rules — some have copays instead of coinsurance, and some have out-of-pocket maximums that cap your total spending.

How to confirm Medicare will cover your knee replacement

Your orthopedic surgeon's office should verify coverage before surgery. Ask them to contact Medicare or your plan to confirm that the procedure is covered and to get an estimate of your out-of-pocket cost. Bring your Medicare card to this conversation.

Medicare requires that your doctor document medical necessity. This means your knee condition — usually severe osteoarthritis, rheumatoid arthritis, or injury — must be significant enough that conservative treatments (physical therapy, injections, medication) have not worked or are not appropriate. Your doctor's notes should show imaging (X-rays or MRI) and a clear reason why surgery is needed now.

If you have a Medicare Advantage plan, the process is similar but the plan itself may require pre-authorization. Call the plan's customer service number on your card and ask whether the surgery needs approval before you schedule it. Some plans require this step; others do not.

Physical therapy coverage after knee replacement

Medicare Part B covers physical therapy after knee replacement surgery. You pay the Part B coinsurance (20% of the approved amount) for each visit, with no separate deductible once you have met it for the year. There is no set limit on the number of visits, but Medicare requires that each visit be medically necessary and that your therapist document progress toward specific goals.

In practice, most people receive 12 to 20 physical therapy visits in the first few months after surgery. If your therapist believes you need more visits, they must show that you are making progress and that additional therapy is still necessary. If Medicare denies further visits, your therapist can appeal the decision.

If you have a Medigap plan, it covers your 20% coinsurance, so physical therapy visits cost you nothing. If you have a Medicare Advantage plan, check your plan documents or call customer service to learn whether physical therapy has a copay or visit limit.

Inpatient versus outpatient knee replacement

Knee replacement can be done as an inpatient procedure (you stay in the hospital overnight) or as an outpatient procedure (you go home the same day). Medicare covers both, but your costs differ.

With inpatient surgery, you owe the Part A hospital deductible plus any coinsurance for days in the hospital. With outpatient surgery, you owe only the Part B deductible and 20% coinsurance on the surgeon's and facility's fees. Outpatient surgery typically costs less out of pocket, but it is not right for everyone — your age, overall health, and home support matter. Your surgeon will recommend which setting is safer for you.

Ask your surgeon's office which setting they are planning and what your costs will be in each case. Some facilities do mostly outpatient knee replacements; others do mostly inpatient. The choice also depends on whether you have someone at home to help you recover.

What Medicare does not cover for knee replacement

Medicare does not cover knee replacement if your doctor considers it elective or cosmetic. It also does not cover the procedure if you have not tried conservative treatments first, unless your condition is so severe that surgery is clearly the only option.

Medicare does not cover certain add-ons or premium implants. If your surgeon recommends a specialized implant that costs more than the standard implant, you may have to pay the difference out of pocket. Ask your surgeon in advance whether any implant or technique they plan to use will result in an extra charge to you.

Certain services related to the surgery — such as transportation to the hospital, home care aides, or equipment rental — are not covered by Medicare Part B. Some may be covered under Part A if you are admitted to the hospital and then transferred to a skilled nursing facility, but this depends on your specific situation.

Medicare Advantage plans and knee replacement

If you have a Medicare Advantage plan, knee replacement is still covered, but the plan's rules explore instead of Original Medicare's rules. Most Medicare Advantage plans cover knee replacement when medically necessary, but they may require pre-authorization, have different copays or coinsurance amounts, or limit which surgeons or facilities you can use.

Before scheduling surgery, contact your Medicare Advantage plan and ask: Does the surgery need pre-authorization? What is my copay or coinsurance? Which surgeons and hospitals are in-network? What is my out-of-pocket maximum for the year? These answers will help you understand your costs and avoid surprises.

If your plan denies coverage, you have the right to appeal. Your surgeon's office can help with this process by providing medical records that show the surgery is necessary.

Frequently Asked Questions

Do I need to wait a certain amount of time after trying physical therapy before Medicare will cover knee replacement?

Medicare does not set a specific waiting period, but your doctor must document that conservative treatments have been tried or are not appropriate for your condition. This usually means showing that physical therapy, injections, or medication have not worked, or that your arthritis is too severe to benefit from them. Your surgeon's notes should explain why surgery is the right next step.

Will Medicare cover a second knee replacement if I need both knees done?

Yes, Medicare covers knee replacement on both knees if both are medically necessary. However, surgeons typically operate on one knee at a time, usually spacing them several months apart to allow recovery. Each surgery is covered separately under the same rules — you pay the deductible and coinsurance for each procedure.

What happens if I have a Medicare Advantage plan and my surgeon is out of network?

Out-of-network care in a Medicare Advantage plan is usually not covered, or you pay much more out of pocket. Before scheduling surgery, confirm that your surgeon and the facility are in your plan's network. If your preferred surgeon is out of network, ask your plan whether they will make an exception or whether you can switch to an in-network surgeon.

Does Medicare cover knee replacement if I am still working and have employer health insurance?

If you are 65 or older and enrolled in Medicare, Medicare is your primary payer even if you have employer insurance. Your employer plan becomes secondary and covers costs Medicare does not. Coordinate with both your employer plan and Medicare to understand your total coverage and out-of-pocket cost.

Can I choose a premium or specialized implant and have Medicare cover it?

Medicare covers the cost of a standard implant. If your surgeon recommends a premium implant (such as a robotic-assisted knee or a specialized material), you may have to pay the difference between the standard and premium cost out of pocket. Ask your surgeon for a cost estimate before surgery so you know what to expect.