Glossary · Coding

Global period

The global period is the defined window of time—0, 10, or 90 days—during which Medicare and most payers consider routine pre- and post-operative care to be bundled into the payment for the surgical procedure itself. For major orthopedic surgery, that window is 90 days.

Verified May 8, 2026 · 6 sources ↓

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Definition

Source · Editorial summary grounded in 6 cited references ↓

When a surgeon performs a procedure, payers don't reimburse each pre-op visit, the operation, and every follow-up separately. Instead, they bundle all of that into a single payment called the global surgical package. The global period is the time boundary that defines how long that bundle applies. CMS assigns one of three lengths: 0 days (minor procedures like injections), 10 days (small procedures such as incision-and-drainage or foreign-body removal), or 90 days (major surgery). For orthopedic surgeons, the 90-day global period governs the vast majority of operative work—total joints, fracture fixation, spinal fusion, arthroscopic reconstruction, and similar cases. The clock starts the day before surgery and runs through the ninetieth post-operative day.

During the global period, routine follow-up visits, wound checks, and normal post-operative management are already paid for through the index procedure's reimbursement. Providers use CPT code 99024 to document these no-charge post-op visits. Services that fall outside the bundle—treatment of a completely unrelated condition, a complication requiring return to the OR, or a planned staged procedure—can be billed separately, but only when the correct modifier is appended and documentation clearly supports why the service escapes the bundle. CMS data show that approximately 32% of all 90-day global procedures are performed by orthopedic surgeons, making accurate global-period management a high-stakes skill in this specialty.

Private payers largely follow CMS global-period rules, but contract terms can vary. Some commercial plans adopt shorter post-operative windows or apply different bundling logic. Coders should verify payer-specific policies before assuming the 90-day Medicare standard applies universally.

Why it matters

Mismanaging the global period has direct financial and compliance consequences. Billing a routine post-op E/M visit without a valid modifier and an unrelated diagnosis will trigger a denial or a Medicare audit flag. Conversely, failing to bill legitimate separately payable services—an unrelated fracture treated during the global window, a staged reconstruction, or a complication requiring return to the OR—is underbilling, which CMS audits catch just as readily as overbilling. CMS studies have found that orthopedic surgeons' observed-to-expected ratio for post-operative visits is only 0.34, signaling that under-documentation of post-op encounters is a real and auditable pattern. Getting the global period right protects both the practice's revenue and its compliance standing.

Common mistakes

Where people most often go wrong with this concept.

Source · Editorial brief grounded in cited references ↓

Billing a standard post-op follow-up visit with a new E/M code instead of CPT 99024, resulting in a duplicate-payment denial.
Appending modifier 24 without linking a distinct, unrelated ICD-10-CM diagnosis code—payers will deny the claim because the unrelated nature of the visit is unproven.
Using modifier 57 (decision for surgery) on a procedure with a 10-day or 0-day global period; modifier 57 applies only to major 90-day procedures.
Forgetting to append modifier 78 when returning the patient to the OR for a complication during the global period, causing the claim to be bundled and denied entirely.
Assuming the 90-day CMS global period applies to all payers without checking the individual commercial payer contract.
Billing a subsequent cast or splint application as a separate service—those are bundled inside the global package and not separately reimbursable.
Failing to document that a staged procedure was planned at the time of the original surgery, making it impossible to justify separate billing with modifier 58.

Related codes

Codes commonly involved when this concept appears in practice.

CPT

Modifiers

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01When does the 90-day global period actually start?

It starts the day before the surgery (day -1) and runs through the 90th day after the procedure date. The day of surgery is day 0.

02Can I bill an E/M visit during the global period if the patient comes in for an unrelated problem?

Yes. Append modifier 24 to the E/M code and link it to an ICD-10-CM diagnosis code that is clearly unrelated to the surgical condition. Without a distinct diagnosis, the payer will bundle the visit.

03What is CPT 99024 and when do I use it?

CPT 99024 is the no-charge code used to document a routine post-operative follow-up visit that is already bundled into the global surgical payment. Use it to maintain an accurate medical record and satisfy any payer reporting requirements without submitting a billable E/M code.

04What is the difference between modifier 78 and modifier 79?

Modifier 78 is for an unplanned return to the operating room to manage a complication related to the original surgery. Modifier 79 is for a procedure that is completely unrelated to the original surgery performed by the same physician during the global period. The distinction drives whether a new global period starts (it does with 79, it does not with 78).

05Does the 90-day global period apply to all payers?

CMS applies the 90-day rule to major surgery under Medicare. Most commercial payers follow a similar structure, but their specific global-period lengths and bundling rules can differ. Always verify payer-specific contracts and policies before assuming Medicare rules apply.

06Does a new global period begin after a return to the OR?

It depends on the modifier. A modifier 79 (unrelated procedure) triggers a new global period for that new procedure. A modifier 78 (related complication) does not trigger a new full global period; payment for the complication procedure is reduced because the pre-op and post-op components are already covered under the original global package.

07Are diagnostic tests and imaging ordered during the global period separately billable?

Yes. Diagnostic tests, lab work, and imaging are not included in the global surgical package and may be billed separately regardless of when they are ordered during the global period.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira AI Scribe

Mira flags the global-period status of every surgical encounter at the time of documentation. When a post-operative visit is recorded within the 90-day (or 10-day) window of an index procedure performed by the same physician or same group, Mira will: 1. Prompt the provider to confirm whether the visit is routine post-op care (auto-populates CPT 99024 and suppresses a billable E/M code) or a separately identifiable service. 2. If a separately identifiable service is confirmed, Mira checks whether the documented diagnosis is clearly distinct from the operative diagnosis. If it is, Mira suggests modifier 24 for E/M services or modifier 79 for unrelated procedures and reminds the coder to link an unrelated ICD-10-CM code. 3. If documentation describes a complication managed surgically, Mira flags modifier 78 and prompts for operative-note language confirming the return to OR. 4. If the visit precedes a major procedure by one day and includes a documented surgical decision, Mira suggests modifier 57. 5. For same-day injections or minor procedures where a significant separate E/M was performed, Mira suggests modifier 25 and checks that the note contains a separately documented clinical decision beyond the pre/post work of the minor procedure. All suggestions are advisory. The provider and coder retain final authority over code and modifier selection.

See Mira's approach

Related terms

Bundling Coding

Bundling is the payer rule that treats two or more CPT codes as a single reimbursable unit, paying only the primary code when the secondary procedure is considered an inherent or integral part of it. Billing the bundled codes separately without proper justification constitutes unbundling, a compliance violation.

Modifier Coding

A modifier is a two-character code—numeric, alphanumeric, or alpha—appended to a CPT or HCPCS code to signal that a service was performed under circumstances that differ from the standard description, without altering the fundamental meaning of the code itself.

CPT code Coding

A CPT code is a standardized five-digit numeric code, maintained by the AMA, that identifies a specific medical or surgical service for billing and reimbursement purposes. In orthopedics, CPT codes cover everything from office visits and joint injections to complex spinal fusions and total joint replacements.