For two decades, the financial risk in Medicare's value-based experiments landed on institutions. Hospitals took on the bundles. Accountable care organizations absorbed the shared savings and the shared losses, while the individual surgeon kept billing fee-for-service and let the layer above sort out the accounting. The Ambulatory Specialty Model breaks that pattern.
Beginning Jan. 1, 2027, CMS will tie a meaningful slice of a clinician's Medicare Part B reimbursement to how their own episode-of-care costs for low back pain stack up against regional peers. The score is calculated at the individual level, not the institution's. The penalty, or the bonus, attaches to the physician.
CMS finalized the model in the 2026 Medicare Physician Fee Schedule on Oct. 31, 2025. It is the agency's first mandatory alternative payment model built around specialists managing chronic conditions in the outpatient setting. For orthopedic, spine, pain, anesthesia and cardiology leaders, the structural shift is worth understanding now, because it changes who carries the risk.
Key Takeaways
The Ambulatory Specialty Model begins Jan. 1, 2027 and runs five performance years through Dec. 31, 2031. Payment adjustments hit two years after each performance year, starting in 2029.
It covers two conditions: low back pain and heart failure. The low back pain cohort sweeps in six specialties: anesthesiology, pain management, interventional pain management, neurosurgery, orthopedic surgery, and physical medicine and rehabilitation. Cardiologists carry the heart failure cohort.
CMS estimates about 8,600 physicians will be pulled in across markets covering roughly a quarter of the nation's core-based statistical areas and metropolitan divisions. Those clinicians account for an estimated $2.8 billion in annual episode spending.
The risk corridor opens at plus or minus 9% of Medicare Part B payments in 2027 and 2028, then widens to 10%, 11% and 12% over the final three years. The adjustment lands on every Part B dollar a participant bills, not only their low back pain work.
Participation is mandatory for clinicians who meet the criteria inside a selected region. There is no opt-out and no hardship exemption. Only physicians who have historically treated at least 20 qualifying episodes per year are included.
What exactly does the Ambulatory Specialty Model do?
ASM scores participants across four categories: quality, cost, care improvement activities and interoperability. CMS benchmarks each clinician against regional peers, then applies a higher rate, the standard rate, or a lower rate to their Medicare Part B payments. The model targets two of the costliest chronic conditions in Original Medicare, low back pain and heart failure, and it aims to reduce avoidable hospitalizations and unnecessary procedures.
The scale is significant. CMS estimates about 8,600 physicians will be enrolled across the chosen markets, which cover roughly a quarter of the nation's core-based statistical areas and metropolitan divisions. Those clinicians account for an estimated $2.8 billion in annual episode spending. The model runs five performance years through 2031, and the financial adjustments arrive two years after each one, starting in 2029.
Why is this different from the value-based models that came before?
Two design choices set ASM apart. First, the scoring is personal. There is no institutional buffer, so a health system cannot fold a lagging surgeon's cost profile into a strong service line and net out even. Second, the risk is portable. Because the adjustment rides on the clinician's own Part B claims, it moves with the clinician to the next employer.
That portability reshapes the math for recruiting and acquisitions. A practice could buy into a hidden two-year rate cut without knowing it. For groups underwriting a deal or hiring spine and pain talent, a physician's ASM standing becomes a financial variable that simply did not exist before.
Who is in the model, and do the affected physicians even know?
Many of them do not. Selection runs quietly on claims data. CMS published a preliminary participant list in February drawn from 2024 claims, and a final 2027 roster built on 2025 data is due in July. A clinician who misses the marks gets no alert. The first signal is a smaller check two years later.
Mike Verdon, MD, a neurosurgeon in Dayton, Ohio, checked the list, found he was not on it, then looked up colleagues who were. "I know a lot of people that are and they don't know," Dr. Verdon told Becker's. The single most concrete step available right now costs nothing: pull the CMS list and find out which clinicians on your roster are in the model.
Why does this land so hard right now?
ASM arrives on a cost base that was already under strain. Orthopedic surgeon pay slipped 3% year over year in 2025 after CMS trimmed the conversion factor by 2.83%. Labor and supply costs ran up 82% per full-time equivalent between 2013 and 2022 in physician-owned multispecialty groups.
"We're just having to fight more every day for the same dollar," Andrew Lovewell, CEO of Columbia, Mo.-based Columbia Orthopaedic Group, told Becker's. ASM is also not the only federal lever pressing on these specialties. The NOPAIN Act is widening access to nonopioid pain treatment, and the WISeR model is layering AI-assisted prior authorization onto the same caseloads. For a spine or pain practice, that is three CMS forces hitting one income statement at once.
Where do specialty leaders disagree?
Opinion is split on whether a model like this is overdue accountability or cost-cutting dressed in value-based language. Some see the logic of standardizing care and reducing unwarranted variation. Amit Momaya, MD, chief of sports medicine at the University of Alabama at Birmingham, told Becker's it is concerning that the same patient with the same pathology can receive very different treatment depending on which office they walk into.
The specialty societies are more skeptical of the model as built. The American College of Surgeons opposed it, arguing the design rewards cost-cutting over team-based care. The American Medical Association pressed CMS to make the model voluntary and to drop a structure that, by its read, cuts reimbursement for most participants regardless of how they perform.
How can revenue cycle discipline blunt the impact?
The leaders best positioned for ASM already know their own episode economics before a payer, employer or government model tells them what those economics should be. Groups that have run bundled payments for years track cost per episode against regional benchmarks as a matter of routine, which is exactly the comparison ASM runs.
Here is the part most relevant to the back office. The spread between average and top-quartile performance on cost, denials and clean claims has grown wide enough to absorb part of the reimbursement squeeze. ASM rewards that discipline and punishes its absence. A practice that treats each denial as an isolated billing problem, rather than a signal about a structural contracting or documentation issue, is the one most exposed when the adjustment hits.
What This Means for Your Practice
If you operate in orthopedics, spine, pain management, interventional pain, anesthesia or cardiology, the first move is simple and free. Pull the CMS participant list and identify which of your clinicians are in the model. Everything that follows depends on knowing who is exposed.
From there, the work is operational. Standardize care pathways for low back pain and heart failure. Build cost-per-episode visibility at the individual physician level so there are no surprises two years downstream. Tighten the revenue cycle functions that ASM scoring rewards, namely clean claim rates, denial prevention and disciplined cost capture. Cosentus works with specialty practices on exactly these levers, turning denial management and reimbursement integrity into a defense against payment models that now score the individual physician.
Frequently Asked Questions
When does the Ambulatory Specialty Model start and how long does it last?
It begins Jan. 1, 2027 and runs five performance years through Dec. 31, 2031. Payment adjustments take effect two years after each performance year, starting in 2029.
Which specialties are affected?
The low back pain cohort includes anesthesiology, pain management, interventional pain management, neurosurgery, orthopedic surgery, and physical medicine and rehabilitation. General cardiology carries the heart failure cohort. Only physicians who have historically treated at least 20 qualifying episodes per year are included.
How large can the payment swing be?
The risk corridor opens at plus or minus 9% of Medicare Part B payments in 2027 and 2028, then widens to 10%, 11% and 12% over the final three years. The adjustment applies to every Part B dollar a participant bills, not only their low back pain or heart failure work.
Can a practice opt out?
No. Participation is mandatory for clinicians who meet the criteria in a selected region. There is no opt-out and no hardship exemption. CMS published a preliminary participant list in February from 2024 claims, with a final 2027 roster built on 2025 data due in July.
What is the single most useful thing to do now?
Pull the CMS participant list and confirm which of your physicians are enrolled, then begin standardizing care pathways and tightening cost-per-episode, denial and clean-claim performance well before the first scored year.
Talk to Cosentus
Payment models that score the individual physician make revenue cycle precision a competitive advantage. Cosentus helps specialty practices in orthopedics, spine, pain management, anesthesia, cardiology and beyond strengthen denial management, reimbursement integrity and cost visibility. Start a conversation at cosentus.com/contact