Medicare Coverage for Hip and Knee Replacement: The Inpatient vs Outpatient Decision

Hip and knee replacement surgery are among the most commonly performed orthopedic procedures for Medicare-age adults. A generation ago, joint replacement always meant a hospital admission, a Part A inpatient claim, and potential access to skilled nursing facility coverage afterward. That has changed significantly. CMS removed hip and knee replacement from the Medicare inpatient-only list, and today a substantial and growing share of these procedures are performed in outpatient settings, hospital outpatient departments or ambulatory surgical centers. That shift has meaningful financial implications that patients need to understand before their surgery date.

Bryce's Take

The outpatient joint replacement shift is one of the most financially consequential changes in orthopedic surgery that most patients still do not know about. I have had clients plan on skilled nursing facility rehab after a knee replacement, get the procedure done outpatient, and discover they do not qualify for Medicare SNF coverage because there was no inpatient stay. Ask your surgeon before the procedure: inpatient or outpatient? The answer changes everything that comes after.

Outpatient joint replacement and what it means for your coverage

When hip or knee replacement is performed as an outpatient procedure, even at a hospital, it is billed under Medicare Part B rather than Part A. Part B applies the standard 20% coinsurance after the annual deductible. The total cost of the procedure can be substantial (the Medicare-approved amount for a total knee replacement often exceeds $15,000), meaning your 20% share can run $3,000 or more before Medigap kicks in. Without Medigap Plan G or N, this is significant out-of-pocket exposure.

The SNF eligibility consequence

The most financially consequential result of outpatient joint replacement: you do not qualify for the Medicare skilled nursing facility benefit afterward. The three-day inpatient hospital stay required to trigger SNF coverage applies only to inpatient admissions. An outpatient procedure, regardless of how complex or how many hours you spend in the facility, does not count. If you need post-surgical rehabilitation in a skilled nursing facility after an outpatient joint replacement, you pay the full cost privately. This can run $400 to $600 per day or more, making it one of the most significant financial surprises in orthopedic care.

Inpatient joint replacement: still an option

Joint replacement as an inpatient admission remains available for patients who meet medical criteria for inpatient-level care. These criteria typically include significant comorbidities, complexity, expected prolonged recovery, or medical instability that warrants 24-hour hospital nursing care. If you meet these criteria and your surgeon documents them appropriately, the procedure can be billed under Part A, the inpatient rules apply, and you qualify for the three-day SNF benefit afterward. Discuss with your surgeon whether your clinical situation supports inpatient admission if post-surgical SNF care is likely.

Ambulatory surgical centers and cost

Some joint replacements are now performed at ambulatory surgical centers rather than hospital facilities. ASC procedures are typically less expensive than hospital outpatient procedures under Medicare's payment system. If your surgeon offers ASC-based joint replacement and your health status permits, the lower facility fee can reduce your total cost-sharing. The same Part B rules and lack of SNF eligibility apply regardless of whether the procedure is at a hospital outpatient department or an ASC.

How Medigap changes the calculation

With Medigap Plan G or N, your 20% Part B coinsurance for an outpatient joint replacement is covered (after the Part B deductible for G, or with potential small copays for N). This significantly reduces the financial exposure from outpatient surgery. However, Medigap does not change the SNF eligibility rules, it covers Part B cost-sharing but cannot convert an outpatient procedure into a qualifying inpatient stay for SNF purposes. Plan for private-pay rehabilitation costs if there is any chance you will need post-surgical SNF care.

Medicare Advantage and joint replacement

Medicare Advantage plans cover joint replacement but may require prior authorization. Authorization requirements and processing times are worth addressing well in advance of a scheduled procedure. Some Advantage plans have preferred facility networks or negotiate bundled payments for joint replacement that affect where you can have the procedure. Verify your plan's requirements, preferred facilities, and whether the procedure will be classified as inpatient or outpatient under the plan's specific coverage rules.

Bryce Casson

Licensed Independent Medicare Broker

Bryce Casson is an independent Medicare insurance broker who works with every major carrier. He does not represent any single insurer, which means his recommendations are based on what actually fits each client's situation, not on commissions or quotas.