Does Medicare Cover Knee Replacement? What to Expect

Does Medicare cover knee replacement? Yes, when your doctor determines it's medically necessary. That includes the surgery, the hospital or surgery center, and much of your recovery care. What you pay depends on two things: your status at the hospital (inpatient or outpatient) and the kind of coverage you have (Original Medicare, a Medigap plan, or a Medicare Advantage plan).

Here's how it works.

When Medicare Considers Knee Replacement Medically Necessary

Medicare doesn't cover knee replacement just because you want one. Your doctor has to document that:

• You have significant knee pain or loss of function that limits daily activities like walking, climbing stairs, or standing.
• X-rays or other imaging show joint damage, usually from arthritis.
• You've tried other treatments first and they haven't worked well enough. That can include physical therapy, pain medication, injections, bracing, or weight management.

Your orthopedic surgeon handles this paperwork. If you're on a Medicare Advantage plan, the surgeon's office will also need to get prior authorization (approval from the plan before surgery) in most cases.

Inpatient or Outpatient: Which Part of Medicare Pays

This is the question that decides most of your cost.

Part A pays if you're admitted as an inpatient.

Part A is hospital insurance. If the hospital formally admits you for the surgery and you stay one or more nights, Part A covers the hospital stay: the room, nursing care, meals, and hospital services. Many knee replacements still happen this way.

Part B pays if the surgery is outpatient.

Part B is medical insurance. Knee replacement used to be inpatient only. Since 2018, Medicare has allowed total knee replacement to be done as an outpatient procedure, and since 2020 it can be done at an ambulatory surgical center (a standalone surgery center). If you go home the same day, or you're kept under "observation" rather than admitted, Part B pays.

One detail worth knowing: the surgeon's fee and the anesthesiologist's fee are always billed under Part B, even if your hospital stay is covered under Part A.

Ask the hospital which status you'll be in before surgery. "Inpatient" and "observation" can look the same from the bed, but they're billed differently.

What You Pay with Original Medicare

If It's Inpatient (Part A)

You pay the Part A deductible, which is $1,736 in 2026. That covers up to 60 days in the hospital during one benefit period. A benefit period starts when you're admitted and ends after you've been out of the hospital (or a skilled nursing facility) for 60 days in a row. Most knee replacement stays are one to three days, so the deductible is usually the only Part A cost.

You also pay 20 percent of the Medicare-approved amount for the surgeon's and anesthesiologist's fees under Part B, after the Part B deductible.

If It's Outpatient (Part B)

You pay the Part B deductible, $283 in 2026, if you haven't already met it this year. After that, you pay 20 percent of the Medicare-approved amount for the facility, the surgeon, the anesthesia, and the implant. Medicare pays the other 80 percent.

The Medicare-approved amount is the price Medicare has agreed to pay for a service. The 20 percent has no yearly cap under Original Medicare, which is one reason many people add a Medigap plan.

What's Covered Before Surgery

Part B covers the care leading up to surgery:

• Visits with your primary care doctor and orthopedic surgeon.
• X-rays, MRIs, and lab work.
• Pre-surgery physical therapy, if your doctor orders it.
• Pre-operative tests like an EKG or bloodwork.

You pay 20 percent for each of these after the Part B deductible.

What's Covered During Recovery

Recovery is where a lot of the care happens, and most of it is covered.

Rehab in a skilled nursing facility.

If you need more recovery help than you can get at home, Part A covers a stay in a skilled nursing facility. Under Original Medicare, you need a qualifying inpatient hospital stay of at least three days first. In 2026, days 1 through 20 cost you nothing, and days 21 through 100 cost $217 per day. Medicare Advantage plans may waive the three-day rule but often require prior authorization.

Home health care.

If you're mostly homebound after surgery and your doctor orders it, Medicare covers part-time skilled nursing and physical therapy at home at no cost to you.

Outpatient physical therapy.

Once you can leave the house, Part B covers physical therapy at a clinic. You pay 20 percent after the deductible. There's no hard limit on the number of visits as long as the therapy is medically necessary.

Medical equipment.

Part B covers durable medical equipment your doctor prescribes, like a walker, crutches, or a continuous passive motion (CPM) machine for your knee. You pay 20 percent, and the supplier has to be enrolled in Medicare.

Prescription pain medication.

Medications you take at home after surgery fall under Part D, not Part A or B. Your drug plan's copay applies.

What Changes with a Medicare Advantage Plan

Medicare Advantage plans (Part C) must cover everything Original Medicare covers, including knee replacement and recovery care. The differences are in how you pay and where you go:

Copays instead of 20 percent.

Most plans charge a daily copay for inpatient stays and a flat copay for outpatient surgery. Amounts vary by plan.

Network.

You'll generally need a surgeon and hospital in the plan's network for the lowest cost.

Prior authorization.

Most plans require approval before surgery, before a skilled nursing stay, and sometimes before home health. Your surgeon's office usually handles it, but confirm it's been done.

Out-of-pocket maximum.

Every Medicare Advantage plan caps your yearly medical costs. For a major surgery, this cap is often the most important number to know. Original Medicare has no cap.

What Changes with a Medigap Plan

Medigap (Medicare Supplement) works with Original Medicare. Depending on the plan letter, it can pay the Part A deductible, the 20 percent Part B coinsurance, and skilled nursing coinsurance. With a comprehensive Medigap plan, a knee replacement under Original Medicare can cost you very little beyond your monthly premiums.

Questions to Ask Before Surgery

• Will I be admitted as an inpatient, or treated as outpatient or under observation?
• Do the surgeon, the hospital, and the anesthesiologist all accept Medicare assignment?
• If I'm on Medicare Advantage: Is everyone in network? Has prior authorization been approved for the surgery and for rehab?
• What's the plan for recovery: home health, outpatient therapy, or a skilled nursing stay?
• Which medical equipment will I need, and is the supplier enrolled in Medicare?

Our Medicare calculator can help you see how the deductibles and coinsurance add up before you go in.

Talk It Through with a Local Agent

If knee replacement is on the horizon and you want to understand what your Medicare coverage will pay, the licensed agents at Clutch City Insurance can walk through it with you. There's no cost and no pressure. We can look at your current plan, explain what to expect from the hospital and rehab bills, and help you ask the right questions before surgery.

Call 713-870-5044, Monday through Friday, 8:30am to 5pm, or contact us online. Our agents speak 17 languages, and home visits are available across the Houston area.