CPT code 21810: deleted code, replacements, and billing guide

Key takeaways

CPT code 21810 was deleted effective January 1, 2015, so a claim carrying it today will be denied.

Its successors are 21811, 21812 and 21813, which share one descriptor and differ only by rib count.

21811 covers 1 to 3 ribs, 21812 covers 4 to 6 ribs, and 21813 covers 7 or more ribs.

No closed-treatment successor exists, so closed care is reported with an E/M code and external fixation with 21899.

CMS gave all three replacement codes a 0-day global period, which makes postoperative visits separately reportable.

CPT code 21810 described treatment of rib fracture(s) requiring external fixation for flail chest. The American Medical Association deleted it effective January 1, 2015, so a claim carrying it today will be denied. It still turns up in legacy chargemasters, superbills and EHR order sets.

Three codes took its place. They are 21811, 21812 and 21813, and all three describe open treatment of rib fractures with internal fixation. The only thing separating them is how many ribs were fixed.

There is no closed-treatment successor. The current CPT set carries no closed-treatment or external-fixation rib fracture code. Those two scenarios are reported a different way.

One more detail trips up billing teams. CMS assigned all three replacement codes a 0-day global period, which changes how postoperative visits are billed.

What was CPT code 21810?

The descriptor read treatment of rib fracture(s) requiring external fixation (flail chest). The code sat in the musculoskeletal system section of the AMA CPT code set, among the fracture and dislocation codes for the neck and thorax.

The code covered a narrow clinical picture. Flail chest happens when three or more consecutive ribs break in two or more places each. That leaves a segment of chest wall moving paradoxically with every breath.

External fixation stabilized that segment from outside the chest wall. The technique fell out of favor as internal plate fixation became the standard repair, and the code went with it.

Is CPT code 21810 deleted?

Yes. CPT code 21810 was deleted effective January 1, 2015. It is invalid on any claim with a date of service on or after that day.

The American College of Surgeons summary of the 2015 CPT changes records the reason. The AMA removed the code because it was barely being used.

Two neighboring codes went the same way. 21800 was deleted in the same 2015 cycle, and 21805 followed a year later, effective January 1, 2016. That is why closed care and open care without fixation both lost their procedure codes.

Search your chargemaster, fee schedule and order sets for all three codes, not just 21810. Denials from a stale order set are slow to trace, and they quietly drag on your revenue cycle.

Check the codes around them one at a time rather than retiring the range. Neighbors like 21433 and 21820 are still current, so a blanket sweep of the 21000 series would delete codes you still need.

What replaced CPT code 21810?

Three Category I codes replaced it. 21811, 21812 and 21813 report open treatment of rib fractures with internal fixation. The AMA created them by converting four Category III codes, 0245T through 0248T.

All three share an identical descriptor. Each one reads open treatment of rib fracture(s) with internal fixation, includes thoracoscopic visualization when performed, unilateral. Only the rib-count suffix differs.

So code selection comes down to a count. Read the operative report, count the ribs that received internal fixation, and pick the tier that matches.

Two rules are built into these codes. Thoracoscopic visualization is included when performed, so it is never billed separately. All three codes are unilateral, so bilateral fixation is reported once with modifier 50 appended.

Count ribs, not fractures. A single rib broken in three places is still one rib when you are choosing between 21811, 21812 and 21813.

How to report closed treatment and external fixation now

Neither has a dedicated CPT code any more. Closed and uncomplicated rib fracture care is reported with the appropriate evaluation and management code. External fixation is reported with 21899, the unlisted procedure code for the neck or thorax.

Closed and uncomplicated rib fracture care

Closed rib fracture care is now an E/M service. When 21800 disappeared, closed treatment stopped being a separately billable procedure, so the visit is captured through E/M coding instead.

That changes what drives the code level. For office and outpatient visits, the level is set by medical decision making or by total time on the date of the encounter. A recorded history and exam no longer sets it.

External fixation of the chest wall

Use 21899 and expect manual pricing. CMS lists 21899 with status indicator C, so the code is carrier-priced and your MAC sets the payment. Its global period is listed as YYY, which means the MAC decides that too.

Submit the operative report with the claim. Name a comparison code, explain how the work differed from it, and state the time and complexity involved. An unlisted-code claim is priced by a person, so the documentation is the whole argument.

Do not reach for 21820

21820 describes closed treatment of a sternum fracture. That is a different bone, and the code carries a 90-day global period. It never substitutes for the deleted rib codes.

ICD-10 codes for rib fractures

Rib fracture claims need a paired ICD-10-CM diagnosis code from category S22. That category covers fractures of the ribs, sternum and thoracic spine, and it records laterality as well as encounter type.

Every code in S22 needs a 7th character. Where the code is shorter than six characters, add the placeholder X first. A fracture of one right rib at the initial encounter becomes S22.31XA, as the CDC ICD-10-CM browser shows.

The 7th character on an S22 code carries six options:

• A – initial encounter for closed fracture.
• B – initial encounter for open fracture.
• D – subsequent encounter for fracture with routine healing.
• G – subsequent encounter for fracture with delayed healing.
• K – subsequent encounter for fracture with nonunion.
• S – sequela.

Those six are not the universal set across the fracture chapter. Skull and facial codes use the same six, so nonunion is S02.651K there. Long bone codes such as S52.001E carry a longer list, because open fractures are graded by Gustilo type.

Trauma services and sports medicine practices meet these codes constantly, because rib injuries are common in both populations. Getting the side and the 7th character right matters as much as the CPT tier. The subsequent-encounter characters carry into rehabilitation records, where physical therapy teams pick them up.

Modifiers for 21811, 21812 and 21813

Two modifier rules matter more than the rest here. The codes are unilateral, and Medicare does not permit co-surgeons on any of them.

The 0-day global period removes several modifiers from the picture. There is no postoperative period to work around, so modifiers 24, 58, 78 and 79 have no role on these claims.

Reimbursement for the replacement codes

There is no Medicare rate for CPT code 21810, because the code no longer exists. Payment for rib fracture fixation now runs through 21811, 21812 and 21813 on the Medicare Physician Fee Schedule.

All three are effectively facility-only. The January 2026 CMS relative value file marks the non-facility practice expense as not applicable, which matches where this surgery happens.

Those dollar figures use the CY2026 conversion factor of $33.4009 for clinicians who are not qualifying APM participants. Qualifying participants are paid on a $33.5675 factor. Both are national and unadjusted, so your locality figure will differ.

The global period is the detail worth acting on. CMS assigned 21811, 21812 and 21813 a 0-day global period when the codes took effect. Every postoperative hospital and office visit after the day of surgery is separately reportable with an E/M code.

Practices that assume a 90-day global on a major thoracic repair leave that follow-up work unbilled. Recovering it only takes documenting each visit as an E/M encounter in its own right.

Commercial payers usually price from Medicare logic at a multiplier. Prior authorization rules differ by plan, so verify them before scheduling a non-emergent rib fixation.

Documentation requirements for rib fracture fixation

Documentation decides the code here, because rib count is the only variable. An operative note that describes hardware without naming the ribs leaves the coder unable to pick a tier. Good clinical form design and disciplined clinical notes prevent that.

Every rib fracture fixation claim needs these elements:

• Operative report: names each rib that received internal fixation, gives the total count, and states the side and the hardware placed.
• A written rib count: a stated number stops a coder inferring the tier from anatomy mentioned in passing.
• Laterality: needed to decide between one unilateral claim line and one line carrying modifier 50.
• Thoracoscopic visualization: record it when used, and remember the code includes it rather than paying for it separately.
• Pre-operative imaging: CT or chest X-ray confirming the fractures, any displacement, and any flail segment.
• Clinical indication: why fixation was necessary, such as flail chest, respiratory compromise or failed conservative management.
• Postoperative visit notes: with a 0-day global period, each visit needs its own E/M documentation to be billable.
• ICD-10 support: history, examination and imaging that substantiate the S22 code you assigned.

Practices that build operative note templates in digital forms can prompt for rib count, side and hardware at the point of care. Practice management software like Pabau turns each of those into a required field, which is much harder to skip than a free-text box.

Common coding errors to avoid

Eight errors account for most denials on rib fracture fixation claims. Most of them come from carrying an old mental model of the code family into a current claim.

• Submitting a deleted code: 21810 and 21800 went in the 2015 cycle and 21805 in the 2016 cycle, so all three deny.
• Hunting for an open versus closed split: all three replacement codes are open treatment with internal fixation. Rib count is the only thing separating them.
• Picking the wrong rib-count tier: 1 to 3 ribs is 21811, 4 to 6 ribs is 21812, and 7 or more ribs is 21813.
• Counting fractures instead of ribs: one rib broken in three places is one rib, not three.
• Reporting bilateral fixation as two lines: the codes are unilateral, so bilateral work is one line with modifier 50.
• Missing the 7th character on an S22 code: S22.31 without its placeholder X and 7th character fails at the edit level.
• Appending modifier 62: CMS assigns these codes a co-surgeon indicator of 0, so co-surgeons are not permitted.
• Bundling postoperative visits: the global period is 0 days, so those visits are separately billable.

How practice management software supports accurate rib fracture coding

The information that decides a rib fracture code lives in the clinical record, not on the claim. If the operative note never states how many ribs were fixed, the coder either queries the surgeon or guesses. Both options cost money.

Pabau keeps that record in one place. Clinical notes, structured forms, uploaded imaging reports and the invoice all attach to the same patient record. A coder confirming a rib count is not chasing three systems to find it.

Pabau’s claims management tools then handle submission and tracking, and validate the payer fields on a claim before it goes out. Your coding team still owns code selection, and the documentation behind it stays retrievable when a payer asks.

That matters most during a chart audit. A trauma or orthopedic service billing 21811 through 21813 can trace every claim back to its operative note. That note carries the rib count, which is the number a reviewer questions first. Broader practice management workflows feed the same discipline.

Keep rib fracture documentation audit ready

Pabau brings operative notes, imaging, forms and claims into one patient record. The rib count behind every 21811, 21812 or 21813 claim stays easy to find.

Book a demo

Conclusion

Treat 21810 as housekeeping with a deadline that passed in 2015. Pull it out of every chargemaster, fee schedule and order set you control, and take 21800 and 21805 with it.

Then simplify how your team thinks about the replacements. There is no open versus closed decision to make, because all three replacement codes are open treatment with internal fixation. The only question is how many ribs the surgeon fixed.

The revenue most often left behind here is postoperative. A 0-day global period makes those follow-up visits separately billable, and plenty of practices never bill them. Book a demo to see how Pabau keeps the operative detail behind each claim in one place.

Continue your research

Coding the diagnosis side of a rib fracture claim? ICD-10 code S22.42XG works through a left multiple rib fracture code and its 7th character in detail.

Billing another thoracic or facial fracture repair? CPT code 21344 covers open treatment of a complicated frontal sinus fracture and its ICD-10 pairings.

Need the nasal fracture equivalent? CPT code 21336 explains open treatment of a nasal septal fracture, including the deleted codes around it.

Coding thoracic outlet decompression too? CPT code 21705 sets out the cervical rib resection code and the diagnoses that support it.

Coding an adjunct for a fracture that will not heal? 20979 covers noninvasive low intensity ultrasound stimulation of bone and its coverage limits.

Frequently asked questions