A knee replacement covered by Original Medicare typically costs you between $2,000 and $8,000 out of pocket, depending on whether the surgery is inpatient or outpatient, whether you have supplemental insurance, and where you live. The total cost of the procedure itself ranges from roughly $30,000 to $50,000 or more, but Medicare picks up the majority of that bill. Your share depends on which parts of Medicare you have and what additional coverage fills the gaps.
How Original Medicare Covers the Surgery
Knee replacement surgery can be performed as either an inpatient or outpatient procedure, and this distinction changes which part of Medicare pays. If you’re admitted to the hospital (inpatient), Part A covers the facility costs. In 2025, the Part A inpatient deductible is $1,676 per benefit period, and that’s your only hospital cost for the first 60 days. You won’t owe a percentage of the total bill on top of that deductible during those 60 days, which is a meaningful difference from outpatient coverage.
If your knee replacement is done on an outpatient basis, which has become increasingly common, Part B covers it instead. Part B works differently: after you meet the $257 annual deductible in 2025, you pay 20% of the Medicare-approved amount for the procedure. On a surgery that Medicare prices at $30,000 to $40,000, that 20% coinsurance could mean $6,000 to $8,000 out of your pocket. That’s a significant sum, and it’s why supplemental coverage matters so much for this particular surgery.
The surgeon’s fee is billed separately under Part B regardless of whether you’re inpatient or outpatient, carrying that same 20% coinsurance. So even with an inpatient stay, you’ll owe 20% of the surgeon’s approved charges on top of the Part A deductible.
What Medicare Requires Before Approving Surgery
Medicare doesn’t cover knee replacement on demand. The procedure must be deemed medically necessary, and CMS guidelines require that three or more specific criteria be met. These include imaging that shows advanced joint disease (such as narrowed joint space or bone cysts), a documented history of conservative treatment that lasted at least three months without success, and pain severe enough to limit your daily activities despite following a care plan. Conservative treatment typically means anti-inflammatory medications, pain relievers, physical therapy, and possibly injections.
If you’ve been managing knee pain for a while with physical therapy, medications, and activity modifications without meaningful improvement, you likely meet the threshold. Your orthopedic surgeon will document this history as part of the approval process. In most cases with Original Medicare, there’s no formal prior authorization required, but the medical record needs to support the decision if it’s ever audited.
Post-Surgery Costs That Add Up
The surgery itself is only part of the bill. Physical therapy after knee replacement is essential, and most people need sessions two to three times per week for several months. Medicare Part B covers outpatient physical therapy with no annual cap on medically necessary services. You’ll pay 20% of the Medicare-approved amount per session after your Part B deductible is met. At roughly $100 to $150 per approved session, that’s $20 to $30 per visit, which accumulates over weeks of rehab.
If you need a short stay in a skilled nursing facility after surgery, Part A covers up to 20 days with no coinsurance, and days 21 through 100 carry a daily coinsurance of $204.50 in 2025. Most knee replacement patients who go to a skilled facility stay fewer than 20 days, so this cost often doesn’t apply. You’ll also have costs for durable medical equipment like a walker or knee brace, covered at 80% under Part B.
How Medigap Plans Reduce Your Costs
Medigap (Medicare Supplement) plans exist specifically to cover the gaps in Original Medicare, and they make a dramatic difference for expensive procedures like knee replacement. The most popular plans, including Plan G, Plan F (for those eligible), and Plans C, D, and N, all cover 100% of Part B coinsurance. That means the 20% you’d owe on the surgeon’s fee and any outpatient facility charges drops to zero.
Plan G, the most widely purchased Medigap plan for new enrollees, covers 100% of Part B coinsurance and the Part A inpatient deductible but does not cover the Part B deductible of $257. So with Plan G and an inpatient knee replacement, your total hospital cost would essentially be $257. Even with an outpatient procedure, Plan G would cover the entire 20% coinsurance, leaving you responsible for only the $257 deductible.
Plans K and L offer partial coinsurance coverage (50% and 75% respectively) but include an annual out-of-pocket limit. Once you hit that cap, they cover 100% for the rest of the year. If you have no Medigap plan at all, the 20% coinsurance on a knee replacement is one of the largest single medical expenses you’re likely to face on Original Medicare.
Knee Replacement Costs on Medicare Advantage
Medicare Advantage plans handle cost-sharing differently from Original Medicare. Instead of the 20% coinsurance structure, most Advantage plans charge fixed copayments or coinsurance percentages that vary by plan, and all plans must include an annual out-of-pocket maximum. In 2025, that maximum cannot exceed $9,350 for in-network services, though the average across all plans is about $5,320 for in-network care. HMO-style plans tend to have lower limits, averaging around $4,091.
Your actual cost for knee replacement on a Medicare Advantage plan depends heavily on your specific plan’s benefit structure. Some plans charge a flat copayment for inpatient surgery (often $250 to $500 per day for a set number of days), while others use a percentage-based coinsurance. A knee replacement could push you close to or past your plan’s out-of-pocket maximum, especially when you add in the surgeon’s fee, anesthesia, physical therapy, and follow-up visits. If you hit that cap, the plan covers 100% of remaining costs for the year.
One important consideration: Medicare Advantage plans often require prior authorization for knee replacement surgery, and they restrict you to in-network surgeons and hospitals. Going out of network on an HMO plan means paying 100% of the cost yourself. PPO plans cover out-of-network care but at substantially higher cost-sharing, with combined out-of-pocket limits averaging around $9,500 to $11,000.
Why Costs Vary by Location
Medicare doesn’t pay a single national rate for knee replacement. The approved amount varies by geographic region based on local cost-of-living adjustments, labor costs, and hospital pricing. A knee replacement in a major urban medical center may carry a Medicare-approved amount tens of thousands of dollars different from the same procedure at a rural hospital. Since your coinsurance is a percentage of that approved amount, your out-of-pocket cost shifts accordingly.
CMS has been working to reduce these disparities through programs like the Comprehensive Care for Joint Replacement (CJR) Model, which sets target prices for hip and knee replacement episodes based on regional averages. Hospitals in the program that keep total episode costs below the target can earn bonuses, while those that exceed it must repay the difference. This has driven episode costs down by about 3.5% at participating hospitals. If your hospital participates in this program, it may be more cost-conscious about the entire episode of care, from surgery through recovery.
Estimating Your Total Out-of-Pocket Cost
Here’s a practical breakdown of what to expect based on your coverage type:
- Original Medicare with Medigap Plan G (inpatient): Roughly $257 total, covering only the Part B deductible. The plan handles coinsurance and the Part A deductible.
- Original Medicare with no supplemental coverage (inpatient): The $1,676 Part A deductible plus 20% of the surgeon’s fee and any Part B services, potentially $3,000 to $5,000 or more total.
- Original Medicare with no supplemental coverage (outpatient): 20% of the entire facility and surgeon bill after the $257 deductible, potentially $6,000 to $8,000 or more.
- Medicare Advantage (in-network): Varies widely by plan, but capped at $9,350 for the year. Most enrollees on HMO plans are protected by a lower average cap around $4,091.
These estimates don’t include the ongoing cost of physical therapy, which could add several hundred dollars over the course of recovery even with Medicare coverage. When budgeting for a knee replacement, plan for three to six months of rehabilitation costs on top of the surgical expenses.