The three most common ancillary lines in orthopedics each follow a different financial logic, a different compliance framework, and a different readiness threshold. Here is how to think through all three before you commit capital.
Key Takeaways
- In-office imaging, physical therapy, and ASC ownership each require different capital thresholds, compliance structures, and operational readiness – treating them as interchangeable is the most common planning error.
- The Stark Law in-office ancillary services exception permits self-referral for imaging and PT within a qualifying group practice, but three conditions – supervision, location, and billing – must all be met simultaneously.
- CMS added 289 surgical procedures to the ASC Covered Procedures List for CY 2026, including procedures removed from the Inpatient Only list, significantly expanding the revenue potential of orthopedic-aligned ASCs.
- MedPAC data shows that over 90 percent of ASCs are for-profit and physician-owned, and that the number of ASCs with major entity co-ownership grew 15.7 percent between 2018 and 2023 – the consolidation pressure on independent owners is real.
The orthopedic group that built its practice entirely on professional fees is leaving money on the table, and most owners know it. What fewer understand is that the three most common ancillary lines – in-office imaging, physical therapy, and ambulatory surgery center ownership – each operate under different financial logic, require different capital, and sit inside different compliance envelopes. Bundling them into a single “ancillary strategy” conversation almost always produces a plan that is coherent in theory and difficult to execute in practice.
Start with scale, because it determines which lines are even available to you. A solo orthopedic surgeon generating $900,000 in professional collections is a different planning problem than a six-physician group with $5 million in billings. In-office imaging can make sense at the smaller end. Physical therapy as a dedicated ancillary line becomes viable somewhere in the middle. ASC ownership requires meaningful surgical volume, capital, and an operational commitment that most practices underestimate until they are six months into the build.
The compliance threshold that governs all three is the Stark Law’s in-office ancillary services exception (IOASE). The exception permits a physician group practice to refer patients for designated health services – including diagnostic imaging and physical therapy – to an entity in which the referring physician has a financial relationship, provided three conditions are satisfied simultaneously: the services must be furnished under the supervision of the referring physician or another physician in the group; they must be delivered at the group’s office or a centralized building used for patient care that meets the regulatory definition; and the services must be billed by the group practice or the supervising physician. All three, not two of three. The exception is frequently described as broad, and it is – but it also has more trip wires than its reputation suggests, particularly around the location requirement and the prohibition on distributing ancillary-line profits based on referral volume.
In-Office Imaging: The Fastest Line to Stand Up, and the Most Audited
Orthopedic practices are among the most common users of in-office imaging, and for straightforward reasons: plain radiography is integral to the clinical encounter, MRI is frequently the deciding study before a surgical discussion, and the reading workflow can be structured so that interpretation happens without meaningful delay. The financial case is compelling at sufficient volume. The compliance case requires precision.
The Stark location requirement is where imaging arrangements most often go wrong. A satellite imaging suite that is not in a “same building” or “centralized building” meeting the regulatory definition does not qualify for the IOASE, regardless of how the ownership is structured. Practices that open a stand-alone imaging center across the street from the clinic, believing they are covered by the exception, are generally not. The CMS regulatory definition of centralized building is narrow, and arrangements that stretch it invite scrutiny. Have counsel review the location facts before the lease is signed, not after the equipment is installed.
HHS-OIG has historically identified imaging as a high-risk category for overutilization under self-referral arrangements. This does not mean in-office imaging is improper – it clearly is not when structured correctly. It means your utilization patterns need to be defensible against the question of whether every ordered study was clinically indicated, documented as such, and ordered at rates consistent with peer norms. A practice that stands up imaging without building the clinical documentation protocols alongside the financial model is creating audit risk that the financial upside does not justify.
The Stark exception permits self-referral for imaging and PT when three conditions are all met. Practices that satisfy two of three have the same legal exposure as practices that satisfy none.
Physical Therapy: The Ancillary Line That Requires the Most Management
In-office PT is the highest-maintenance ancillary line in orthopedics, and it is frequently the least profitable relative to expectation. The licensing requirement for licensed physical therapists – as opposed to physician extenders – means that labor cost is relatively fixed, productivity is bounded by patient hours, and the practice absorbs significant overhead before a single Medicare dollar arrives. The IOASE covers PT when the supervision and location conditions are met, but the billing rules are particular: incident-to billing under the physician’s NPI is available in some settings and not others, and the distinction between services that qualify for incident-to and those requiring direct therapist billing affects the revenue model materially.
The cases where in-office PT genuinely adds value are those where the group has enough surgical volume to fill a PT schedule with post-operative patients who would otherwise be referred out, where the group can negotiate with commercial payers for PT rates that make the model work, and where the operational management of the PT department does not land on a surgeon’s desk. A PT line that is administratively managed by clinical staff who also run the clinic schedule will underperform and create compliance exposure simultaneously.
ASC Ownership: The Highest-Leverage Line at Sufficient Volume
Ambulatory surgery centers are the most capital-intensive and highest-upside ancillary structure available to orthopedic groups. MedPAC’s March 2025 report noted that over 90 percent of ASCs are for-profit and primarily physician-owned, and that the number of ASCs with major-entity co-ownership grew by 15.7 percent between 2018 and 2023. Those numbers reflect both the financial attractiveness of ASC ownership and the competitive dynamic building around it: health systems, private equity, and national ASC management companies are all seeking physician co-ownership arrangements, and the surgeon who waits too long to evaluate their options may find the available deals are less favorable.
For CY 2026, CMS finalized the addition of 289 surgical procedures to the ASC Covered Procedures List, including procedures transferred from the Inpatient Only list, and implemented a 2.6 percent payment rate update. Total knee replacement and a growing list of spine procedures now qualify for ASC-level reimbursement. The practical implication for an orthopedic group evaluating ASC development or co-investment is that the procedure list and the reimbursement landscape are both more favorable than they were five years ago.
The build-versus-buy-versus-partner decision is where most groups spend insufficient time. Building de novo requires capital, certificate-of-need analysis in applicable states, licensing timelines measured in years, and operational infrastructure your group almost certainly does not already have. Buying into an existing ASC is faster but requires careful due diligence on payer contracts, case mix, and the governance terms of the ownership agreement. Partnering with a management company means giving up a share of the economics in exchange for operational infrastructure – a trade that is often worth making, but only if you understand the management fee structure and the exit provisions before you sign.
From the Field
A five-physician orthopedic group in the Mid-Atlantic had been referring all post-surgical PT to an independent outpatient clinic down the street, and had debated building in-office PT for three years without moving forward. The practice evaluation found that the PT economics were marginal at their surgical volume, but that the group was leaving significant imaging revenue on the table: MRI utilization was consistent with clinical norms, but all scans were being read at a hospital-affiliated radiology practice under a shared services agreement that had not been renegotiated in four years. Our fractional CFO engagement modeled the imaging line, worked through the Stark location analysis with practice counsel, negotiated a professional reading agreement with an independent radiology group, and built the billing protocols. The group stood up in-office MRI within fourteen months, without the PT line they were not ready to manage. Ancillary revenue from imaging added a meaningful per-physician income supplement on volume that was already there.
The Decision Sequence That Actually Works
Model the line before you capitalize it. That means running real break-even math: how many scans per week at what reimbursement rate cover the equipment lease, the service contract, the technologist, and the Stark compliance overhead? Most ancillary decisions in orthopedics are made at the wrong level of abstraction – “imaging is profitable for practices like ours” – without a practice-specific model that accounts for your payer mix, your referral patterns, and the supervision capacity you actually have.
Then sequence the compliance review before the capital commitment. Counsel should review the Stark analysis, the supervision structure, and the billing methodology before equipment is ordered or a management contract is signed. State law adds another layer: some states have their own self-referral prohibitions that are stricter than the federal Stark Law, and several states have certificate-of-need requirements that affect ASC development. A plan that is legally sound under federal law may still require significant modification at the state level.
A consultant can build the financial model, map the compliance requirements, and hand you a plan that is analytically correct. If you have an administrator with the bandwidth and the background to execute the implementation – negotiating payer contracts, building the billing infrastructure, managing the Stark documentation – consulting is a legitimate and often more economical choice. The practices that stall are typically those where the plan is solid and the execution capacity is not. A fractional executive does the modeling and then sits in your credentialing calls, works your payer contracting alongside your administrator, and builds the billing protocols with your team until the line is running on its own.
Sources
- MedPAC, Ambulatory Surgical Center Services: Status Report, March 2025 — https://www.medpac.gov/wp-content/uploads/2025/03/Mar25_Ch10_MedPAC_Report_To_Congress_SEC.pdf
- CMS, Ambulatory Surgical Center Payment – January 2026 Update (MM14359) — https://www.cms.gov/files/document/mm14359-ambulatory-surgical-center-payment-january-2026-update.pdf
- Cranfill Sumner LLP, Stark Law Essentials: The In-Office Ancillary Services Exception — https://www.cshlaw.com/resources/stark-law-essentials-the-in-office-ancillary-services-exception/
- American Urological Association, In-Office Ancillary Services Exception Issue Brief — https://www.auanet.org/documents/advocacy/advocacy-by-topic/IOASE-JAC-Issue-Brief.pdf
More in the Orthopedics Series
- Payer Contracting in Orthopedics: Fee Schedules, Bundles, and TEAM — what your commercial contracts actually pay and how the mandatory TEAM bundled model changes the math.
- Orthopedic Physician Compensation: wRVUs, Conversion Factors, and What Goes Wrong — the compensation model that pays for performance without generating partner disputes.
- The PE Offer in Orthopedics: What to Evaluate Before You Sign — the framework for evaluating a PE offer against a credible independence plan.
- Block Time and Clinic Flow: The Throughput Problem Most Orthopedic Groups Ignore — the scheduling and block time changes that increase surgical volume without adding a surgeon.