CMS Knee Replacement Bundle and the Physical Therapy Cap

Starting January 1, 2028, Medicare’s mandatory nationwide joint-replacement bundle will put participating hospitals at financial risk for nearly all related Part A and Part B spending through 90 days, including physical therapy. That creates a direct incentive to restrain rehabilitation costs, although CMS has not imposed a knee-replacement-specific PT visit cap and the hospital’s target price is not the patient’s personal therapy allowance. A legal summary of CMS-1849-F describes the finalized model and 90-day episode.

The distinction matters at the patient level. A hospital can benefit when episode spending falls below its CMS target and can owe money when spending exceeds it. Physical therapy is among the downstream costs that can affect that reconciliation. Quality requirements, medical-necessity rules, documentation standards, and beneficiary protections remain in place, but the payment model still gives hospitals a reason to standardize and economize post-operative care.

Enter your hospital’s target and expected 90-day costs; the result shows how many PT visits fit before the episode exceeds its target.

The Consensus View Is Right About Coverage, but Not Incentives

The conventional explanation is that bundled payment changes hospital accounting rather than a patient’s treatment entitlement. That is substantially correct.

Under the original Comprehensive Care for Joint Replacement model, providers generally continued billing through Medicare’s existing payment systems. CMS then compared attributed episode spending with the hospital’s target price. The hospital, rather than the beneficiary, faced retrospective financial reconciliation. CMS also said beneficiaries retained existing protections and freedom to choose providers and services. CMS describes the original model’s payment structure and beneficiary protections.

A target price therefore is not a beneficiary coverage maximum, guaranteed rehabilitation budget, predetermined visit allowance, or clinical discharge instruction. A PT claim still must satisfy the Medicare benefit, medical-necessity, documentation, coding, and billing rules that apply to that service.

The consensus view becomes incomplete when it treats financial reconciliation as irrelevant to care planning. Hospitals can respond to a fixed episode target by creating preferred-provider networks, standard pathways, discharge protocols, and utilization expectations. Because related physical therapy contributes to episode spending, reducing PT spending can improve the hospital’s financial result even though no CMS rule says that a patient receives a fixed number of visits.

CMS built in a quality counterweight: a hospital must clear a minimum composite quality score before collecting a reconciliation payment. That reduces, but does not erase, the incentive to hold down downstream spending.

The defensible verdict is narrow. The bundle is not a legal PT cap, and it does not override medical necessity or coverage rights. It does make rehabilitation part of the hospital’s 90-day financial calculation.

The 90-Day Price Reaches Beyond the Hospital Stay

CMS finalized CMS-1849-F on July 31, 2026, according to the supplied legal summary. The mandatory nationwide CJR-X model is reported to begin January 1, 2028 and replace the original CJR pilot, which ran from April 1, 2016 through December 31, 2024.

The successor model covers eligible hip, knee, and inpatient ankle replacements at most acute-care hospitals paid under the Inpatient Prospective Payment System and Outpatient Prospective Payment System. Reported exemptions include hospitals participating in the Transforming Episode Accountability Model, Maryland hospitals, and hospitals not paid under both systems.

For an inpatient procedure, the episode extends through 90 days after discharge. For an eligible hospital-outpatient procedure, it extends through 90 days after the procedure. It captures nearly all related Medicare Part A and Part B spending, including physical therapy and follow-up visits, subject to the model’s exclusions.

That period answers an accounting question: which services count when CMS assesses the hospital’s episode spending? It does not establish an ideal rehabilitation duration or require discharge from therapy on day 90.

A medically necessary visit on day 100 falls outside the earlier episode calculation, but that fact alone neither approves nor denies the claim. A visit inside the episode can count toward hospital spending while still requiring its own coverage and documentation support.

The supplied secondary summary does not reproduce every exclusion or operating instruction in the final rule. Hospitals and clinicians making compliance decisions need the controlling rule and subsequent CMS guidance rather than an inferred list of covered services.

Hospitals Gain When Episode Spending Stays Below Target

The model’s financial mechanism is straightforward. CMS sets an episode target price. If qualifying spending is below that target and the hospital meets the quality requirements, the hospital may receive a reconciliation payment. If spending exceeds the target, the hospital may owe money to CMS under the applicable risk rules.

Physical therapy competes within that calculation with other related costs. Those can include the operation and hospital services, follow-up care, home health, rehabilitation, and the cost of a complicated recovery or readmission. The supplied CMS materials do not provide a single representative knee-replacement target price or standard PT visit cost, so a credible national visit allowance cannot be calculated from them.

The arithmetic nevertheless explains the incentive. The amount remaining for PT equals the episode target minus other attributed episode spending. Dividing that remainder by the attributed cost per PT visit produces the number of visits that fit financially before the target is exceeded.

That is not the number Medicare says the patient clinically needs. It is the point at which additional attributed spending begins worsening the hospital’s reconciliation position.

A hospital may never describe its pathway as a cap. Patients may instead encounter a standard visit schedule, pressure to use home exercises sooner, a preferred therapy provider, or a recommendation to discharge once a protocol’s basic criteria are met. None of those facts proves that care was improperly reduced. They do show why the clinical reason for a proposed discharge should be separated from the hospital’s episode budget.

The $2,480 Threshold Is a Billing Rule, Not the Bundle

A separate Medicare policy often gets confused with the 90-day episode. The Bipartisan Budget Act of 2018 repealed the former statutory outpatient therapy caps and exceptions process. The old cap amounts now operate as annual thresholds connected to claims requirements.

For calendar year 2026, the threshold is $2,480 for physical therapy and speech-language pathology combined. Occupational therapy has a separate $2,480 threshold. Claims above the applicable amount require the KX modifier, which indicates that continued services are medically necessary and supported by the record. Claims exceeding the threshold without the required modifier are denied. CMS explains the 2026 thresholds and KX requirements.

Crossing $2,480 does not itself require therapy to stop. The modifier also does not make an unsupported service payable or guarantee that Medicare will pay the claim.

The PT and SLP amount is annual and combined. It does not reset after knee surgery, when a patient starts a new plan of care, or when the patient changes therapists. PT for another condition or SLP received earlier in the same calendar year can cause a patient to reach the threshold sooner during knee rehabilitation.

The $2,480 figure applies to 2026 and is indexed annually. It should not automatically be reused for services in 2028, when CJR-X is reported to begin. The draft evidence does not provide the threshold that will apply in 2028.

The $3,000 Review Threshold Is Not an Automatic Denial

The $3,000 PT and SLP combined threshold serves another purpose. Claims above it may become eligible for targeted medical review. Occupational therapy has a separate $3,000 threshold.

CMS guidance supplied for this article applies that targeted-review policy through 2027 and says not every claim above the threshold is reviewed. Crossing $3,000 does not create a maximum benefit, guarantee review, trigger automatic denial, or require discharge.

Medical necessity and adequate documentation matter below and above both annual thresholds. A claim below $2,480 is not automatically covered, and a claim above $3,000 is not automatically improper.

These thresholds come from Original Medicare outpatient therapy guidance. They do not establish the authorization, network, referral, or cost-sharing rules of a particular Medicare Advantage plan. They also do not determine payment for therapy billed under home health, skilled nursing facility, or inpatient rehabilitation benefits.

A Short Rehab Schedule Needs a Clinical Explanation

If a hospital or therapist proposes reducing therapy, ask whether the reason is clinical, financial, or related to claim requirements. “The bundle only allows this many visits” does not identify a Medicare coverage rule.

The useful written questions are specific:

• What functional findings support discharge or a reduced schedule?
• Is the stated limit a hospital pathway, a health-plan authorization, or an individual Medicare claim decision?
• Is the concern medical necessity, missing documentation, network status, or the hospital’s episode target?
• Have earlier PT or SLP services contributed to the calendar-year threshold?
• If the KX threshold has been crossed, will the provider use the modifier and document the need for continued skilled care?
• If coverage is being denied, what written notice and appeal instructions apply?

A patient’s rehab record should connect skilled treatment to documented limitations and progress. For knee replacement, that may include the measurements and tasks actually being treated, such as knee extension, gait, stair use, strength, transfers, or the ability to return to ordinary walking. The appropriate milestones and treatment plan are individual clinical decisions; no single milestone guarantees coverage or proves that more visits are necessary.

If therapy is ending before the treating team’s documented goals are met, ask the clinician to explain whether the goals changed, progress plateaued, skilled treatment is no longer required, or a nonclinical utilization rule is being applied. Request the answer and any coverage decision in writing.

Do not delay urgent assessment because of a billing dispute. New chest pain, shortness of breath, marked calf swelling, fever, wound drainage, or rapidly worsening pain after knee replacement requires prompt medical guidance.

The Model’s Start Date Matters

The original CJR model ended December 31, 2024. CMS proposed a nationwide CJR-X expansion in April 2026 with an October 1, 2027 start, but that was a proposal rather than final policy. The April legal analysis identifies that date as proposed.

The later summary of CMS-1849-F reports a January 1, 2028 start. Patients should not assume that the old CJR model remains active everywhere during the gap or that CJR-X has already begun. Another payment arrangement may apply, and CJR, CJR-X, BPCI, BPCI Advanced, and TEAM are distinct programs.

Once CJR-X begins, the central patient protection is precision about what a quoted limit means. The 90-day bundle gives hospitals a financial target. The $2,480 amount is a 2026 KX threshold. The $3,000 amount concerns possible targeted review. None is a national knee-replacement PT visit cap.

The payment incentive is still real. When related rehabilitation sits inside a fixed 90-day target, fewer attributed visits leave more room under that target. A patient asked to finish therapy before clinically documented recovery goals are met should request the clinical and coverage rationale rather than accept “the bundle” as a complete explanation.