The Orthopaedic Global Period Guide: Mastering Modifiers 24, 25, 57, 58, 78, and 79 in 2026

Global period modifiers tell a payer that a service performed during a surgery's global window should be paid separately, and using them correctly is one of the largest recoverable revenue opportunities in orthopaedic billing. In short: modifier 24 covers an unrelated E&M during the global period, modifier 25 covers a separate same-day E&M, modifier 57 covers the E&M that decides on major surgery, modifier 58 covers a staged or planned related procedure, modifier 78 covers an unplanned return to the OR for a related complication, and modifier 79 covers an unrelated procedure during the global period.

Orthopaedics lives inside global periods more than almost any specialty, so misapplying these modifiers means either leaving money on the table or inviting denials and audit risk. This guide breaks each modifier down with the rule, an orthopaedic example, and the documentation you need to defend it.

What a Global Period Is and Why It Matters in Orthopaedics

Under CMS rules, most surgical procedures carry a global period, commonly 0, 10, or 90 days, during which routine post-operative care is bundled into the surgical payment and not billed separately. Major orthopaedic procedures such as joint replacements and fracture repairs typically carry 90-day globals, which means a large share of follow-up care falls inside the window. Because so much orthopaedic care happens during these windows, knowing when a service breaks out of the global, and which modifier signals that, is essential to getting paid for work that is genuinely separate.

Modifier 24: Unrelated E&M During the Global Period

Modifier 24 is appended to an E&M service performed during another procedure's global period when that visit is unrelated to the original surgery. Example: a patient who is 40 days out from a knee replacement returns for a new, unrelated shoulder complaint. The documentation must clearly establish that the visit addresses a different problem, ideally with a distinct diagnosis, so the payer can see the E&M is not routine post-op care.

Modifier 25: Significant, Separately Identifiable E&M on the Same Day

Modifier 25 applies when a significant, separately identifiable E&M service is performed on the same day as a procedure. Example: a patient presents for evaluation of knee pain, the surgeon performs a full workup and decides to also administer a joint injection the same day. The E&M is billable with modifier 25 if the evaluation went beyond the routine work associated with the injection. The note must show the E&M stands on its own.

Modifier 57: The Decision for Major Surgery

Modifier 57 is appended to the E&M service at which the decision to perform major surgery (a 90-day global procedure) was made, typically the day before or the day of surgery. Example: a patient is evaluated and the surgeon decides that day to proceed with a total hip replacement the next morning. That decision-making visit is separately billable with modifier 57. Confusing 57 with 25 is a common and costly error, so match the modifier to the global period of the planned procedure.

Modifier 58: Staged or Related Procedure

Modifier 58 signals a procedure during the global period that was planned or staged, was more extensive than the original, or was for therapy following a diagnostic procedure. Example: a planned hardware removal following a fracture repair, or a staged bilateral procedure done in two sessions. The key word is planned. Documentation should reflect that the subsequent procedure was anticipated as part of the treatment course.

Modifier 78: Unplanned Return to the OR for a Related Complication

Modifier 78 applies when the patient must return to the operating room during the global period for an unplanned, related problem, such as a post-operative complication. Example: a patient returns to the OR for irrigation and debridement of a surgical site infection following a fracture repair. Because the return is unplanned but related, modifier 78 preserves appropriate payment without starting a new global period.

Modifier 79: Unrelated Procedure During the Global Period

Modifier 79 is used when a procedure performed during the global period is entirely unrelated to the original surgery. Example: a patient in the global period after a right knee replacement fractures the left wrist and undergoes fixation. The wrist procedure is unrelated, so modifier 79 applies and a new global period begins for the second procedure.

How to Stop Losing Revenue to Global Period Errors

The practical problem is not understanding these modifiers in the abstract; it is applying them correctly and consistently across thousands of encounters when coders are under time pressure. This is where AI coding earns its keep: an autonomous coder checks the global period status of prior procedures, evaluates the relationship of the current service, and applies the correct modifier with supporting documentation attached, every time. Maia's AutoCoder is built to handle exactly this orthopaedic-specific modifier logic before a human coder ever touches the chart.

Frequently Asked Questions

What is the difference between modifier 25 and modifier 57?
Modifier 25 is for a significant, separately identifiable E&M on the same day as a minor procedure. Modifier 57 is for the E&M at which the decision for major (90-day global) surgery was made. Match the modifier to the global period of the related procedure.

When do I use modifier 58 versus modifier 78?
Use 58 when the return to the OR was planned or staged, or is more extensive follow-up therapy. Use 78 when the return is unplanned but related, such as a complication. Modifier 78 does not start a new global period; 58 does.

Does modifier 79 start a new global period?
Yes. Because the procedure is unrelated to the original surgery, modifier 79 triggers a new global period for that second procedure.

What documentation do I need for modifier 24?
Documentation showing the E&M during the global period is unrelated to the original surgery, ideally supported by a distinct diagnosis, so it is clearly not routine post-operative care.

Which orthopaedic procedures have a 90-day global period?
Most major procedures, including joint replacements and many fracture repairs, carry 90-day global periods. Always verify the specific global assignment for the CPT code, as CMS defines these per procedure.

The Bottom Line

Global period modifiers are where orthopaedic practices most often lose defensible revenue, either by omitting a modifier that unlocks separate payment or by applying one that cannot survive an audit. Getting them right consistently is a coding-accuracy problem best solved with specialty-built automation.

See how Maia's AutoCoder handles this automatically for orthopaedic practices. Book a demo at usemaia.com.