Out-of-Pocket Costs for Total Knee Arthroplasty: Medicare vs. Commercial Insurance

By Editorial team · Published September 16, 2026

Understanding Total Knee Arthroplasty and Billing Structures

Total knee arthroplasty, commonly referred to as total knee replacement, is a surgical procedure in which damaged bone and cartilage from the knee joint are removed and replaced with artificial components made of metal, plastic, or ceramic materials (Source 1). The clinical goal of this procedure is to relieve chronic joint pain and restore mobility when conservative treatments fail (Source 1). From a financial standpoint, however, a total joint replacement represents a complex sequence of medical billing events spanning multiple providers and care settings.

Medical bills for knee replacement surgery are divided into two main categories: professional fees and facility fees. Professional fees account for the individual clinical services rendered by healthcare professionals, including the orthopedic surgeon, assistant surgeon, and anesthesiologist. Facility fees account for the operational overhead of the facility where the surgery takes place, covering the operating room, recovery units, nursing care, surgical supplies, and the physical implant hardware.

Calculating your final knee replacement cost out of pocket requires analyzing how these line items interact with your specific health insurance policy. Whether coverage is provided through traditional Medicare, a Medicare Advantage plan, or a commercial employer-sponsored policy, the patient's financial responsibility is governed by deductibles, coinsurance percentages, prior authorization rules, and annual out-of-pocket limits.

Inpatient Hospital vs. Outpatient ASC Settings

Historically, total knee arthroplasty was performed almost exclusively as an inpatient hospital procedure requiring an multi-day stay. Advances in minimally invasive surgical techniques, localized pain protocols, and early physical rehabilitation have shifted a significant portion of total joint replacements to outpatient settings. Outpatient procedures may take place in a Hospital Outpatient Department (HOPD) or an independent Ambulatory Surgical Center (ASC).

The surgical setting directly impacts the magnitude of the hospital facility fee knee surgery charge. Inpatient hospital admissions incur higher base operational overhead because the facility must maintain round-the-clock inpatient nursing care, room and board, pharmacy services, and emergency backup capacity. In contrast, an ASC operates under a streamlined administrative structure tailored specifically to same-day procedures, resulting in lower base facility charges according to CMS payment data and commercial fee schedules.

Medicare Coverage Mechanics: Part A vs. Part B Obligations

For Medicare beneficiaries, out-of-pocket liabilities for joint replacement depend on whether the hospital stay is formally classified as an inpatient admission under Part A or an outpatient procedure under Part B. The Centers for Medicare & Medicaid Services (CMS) removed total knee arthroplasty from its Inpatient-Only (IPO) list, allowing physicians to determine the appropriate setting based on medical necessity.

When a knee replacement is performed as a formal inpatient admission, Medicare Part A joint replacement coverage applies to the hospital facility charges. Under Part A, the beneficiary is responsible for a single benefit period deductible ($1,632 according to 2024 CMS data) for hospital stays lasting between 1 and 60 days. If the patient has already met the Part A deductible for a prior hospital stay within the same 60-day benefit period, no additional facility deductible is owed for the inpatient stay.

When total knee arthroplasty is performed on an outpatient basis (at an HOPD or ASC), Medicare Part B joint replacement coverage applies to both facility and professional services. Under Part B, the beneficiary must first satisfy the annual Part B deductible ($240 according to 2024 CMS data). After the deductible is met, the patient is responsible for a 20% coinsurance for the Medicare-approved amount of the physician's fees, anesthesiologist's fees, and facility charges.

Federal regulations establish a statutory cap on outpatient hospital facility coinsurance under Medicare Part B. The 20% coinsurance for the HOPD facility charge cannot exceed the value of the inpatient Part A deductible for a single service. However, professional physician fees under Part B are not subject to this cap, and ASC facility coinsurance remains a strict 20% of the Medicare-approved payment rate. Beneficiaries with supplemental coverage, such as a Medigap policy, typically have most or all of these 20% coinsurance amounts covered, whereas those enrolled in original Medicare without supplemental coverage must pay these costs out of pocket.

Commercial Insurance Structures: Deductibles, Coinsurance, and Out-of-Pocket Maximums

Commercial health insurance plans, including Preferred Provider Organization (PPO) and High Deductible Health Plan (HDHP) structures, handle total joint replacement costs through a tiered cost-sharing design. Unlike traditional Medicare, commercial plans feature an annual Out-of-Pocket Maximum (OOPM) that caps the total dollar amount a patient can be required to pay for covered in-network services during a plan year.

Under a commercial policy, the patient is responsible for paying 100% of allowed charges until their individual or family deductible is satisfied. Once the deductible is met, the plan shifts to coinsurance, where the patient pays a percentage (frequently 10% to 30% for in-network care according to standard commercial fee structures) of every billed line item—including surgeon fees, facility fees, pathology, and pharmacy. Coinsurance payments continue until the total of all deductibles, copayments, and coinsurance reaches the plan's annual out-of-pocket maximum.

Pre-authorization is a critical procedural requirement under almost all commercial plans. Insurance carriers require the surgeon's office to submit clinical documentation demonstrating that the patient has tried conservative therapies (such as physical therapy, nonsteroidal anti-inflammatory drugs, or corticosteroid injections) prior to approving surgery. Failure to secure prior authorization can lead to an administrative denial, leaving the patient liable for the total cost of the procedure.

Post-Acute Care: Physical Therapy and Rehabilitation Expenses

The financial obligation for total knee replacement does not end when the patient leaves the operating recovery room. Post-operative rehabilitation is necessary to regain joint motion, rebuild quadriceps strength, and ensure proper implant function (Source 1). Out-of-pocket costs during the post-acute phase accumulate across outpatient physical therapy, home healthcare services, and durable medical equipment (DME).

Outpatient physical therapy protocols typically prescribe two to three sessions per week for a duration of six to twelve weeks following surgery. Under commercial insurance, physical therapy sessions often trigger a total knee arthroplasty copay per visit (ranging from $25 to $75 per session in standard commercial benefit structures) or a 20% coinsurance payment per session. Some commercial plans enforce annual visit limits (such as 20 or 30 visits per year), after which the patient must pay 100% of the physical therapy rate unless a medical necessity extension is granted.

Under Medicare Part B, physical therapy services are covered at 80% of the Medicare fee schedule once the Part B deductible is met, leaving the beneficiary responsible for 20% coinsurance per session. In addition, post-surgical durable medical equipment—including standard walkers, crutches, continuous passive motion (CPM) machines, and specialized knee braces—is billed separately. Medicare Part B covers medically necessary DME under its standard 80/20 cost-sharing split, while commercial plans apply applicable deductible and coinsurance rates.

Navigating Hospital Financial Assistance Policies and No Surprises Act Protections

Patients evaluating prospective medical bills should be aware of federal statutory protections against unexpected out-of-network medical expenses. Under the federal No Surprises Act, patients receiving scheduled non-emergency care at an in-network hospital or outpatient surgical facility are protected from balance billing by out-of-network individual providers. For example, if an in-network orthopedic surgeon utilizes an out-of-network assistant surgeon or anesthesiologist during the procedure, the out-of-network provider cannot bill the patient more than the standard in-network cost-sharing amount.

For patients facing substantial remaining out-of-pocket costs after insurance processing, non-profit healthcare systems are required by federal law (Section 501(r) of the Internal Revenue Code) to maintain formal Financial Assistance Policies (FAPs). These policies provide free or discounted emergency and medically necessary care to eligible individuals based on household income levels relative to the Federal Poverty Guidelines.

Prior to settling final accounts, patients should request an itemized statement listing all individual procedural codes (CPT codes) and facility billing revenue codes. Reviewing itemized statements allows patients to verify that all billed charges reflect services actually received, confirm that insurance adjustments were properly applied, and negotiate payment schedules or charity care discounts directly with the hospital's billing department.

How does an outpatient knee surgery cost compare to an inpatient stay?

Outpatient settings like Ambulatory Surgical Centers (ASCs) typically carry lower overall facility fees than inpatient hospital stays. However, your actual out-of-pocket expenses depend on whether your plan applies a deductible, a fixed copayment, or a percentage coinsurance to the specific facility classification.

What is the primary difference between facility fees and physician fees?

Physician fees cover the professional medical services rendered directly by the orthopedic surgeon, assistant surgeon, and anesthesiologist. Facility fees cover the cost of the operating room, recovery space, nursing care, surgical equipment, and the implant device.

Does Medicare Part B cover all costs for outpatient total knee replacement?

No. Medicare Part B covers 80% of the Medicare-approved amount for medically necessary outpatient services after you satisfy your annual Part B deductible. You are responsible for the remaining 20% coinsurance unless you have supplemental insurance such as a Medigap plan.

Sources

1. NIH Health Information: Joint Replacement — National Institutes of Health

This article is for general information only and is not professional advice. Figures come from public sources and change over time; check the official source before you act.

Sponsored

More from Real Money Net

• Heat Pump HVAC Conversion Costs: Federal Rebates, Tax Credits, and System Sizing
• Business Fiber Internet vs. Dedicated Internet Access (DIA): Architecture, Cost, and SLA Comparison
• International Medical Evacuation and Travel Health Coverage: Policy Limits and Out-of-Country Costs
• Used EV Tax Credit Rules: Eligibility, Income Caps, and Battery Degradation Checks
• Commercial Auto Insurance Coverage: Liability Limits, Business Use Rules, and Fleet Pricing
• IRS Section 25D Residential Solar Tax Credit: Sizing, Battery Rules, and ROI Calculation