ICD-10 Code S52.551C: Other extraarticular fracture of lower end of right radius

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Key takeaways

ICD-10 code S52.551C is a billable 2026 ICD-10-CM code, and it applies to initial encounters only.

The seventh character C designates an open fracture graded Gustilo type IIIA, IIIB, or IIIC at the first course of treatment.

The S52.551 family carries 16 valid seventh characters, because the letters I, L and O are skipped.

Gustilo grade is an intraoperative call by the surgeon, so the operative note must state it before a coder assigns C.

Practice management software like Pabau validates CPT and ICD pairings through Claim.MD before an open fracture claim reaches the payer.

ICD-10 code S52.551C is the billable diagnosis code for an other extraarticular fracture of the lower end of the right radius.

It applies to the initial encounter for an open fracture graded Gustilo type IIIA, IIIB, or IIIC.

The code became effective October 1, 2025, as part of the 2026 ICD-10-CM edition, and it is valid for claim submission. Two details decide whether it holds up. The seventh character must match the encounter stage, and the operative note must name the Gustilo grade.

This reference covers the billable status, all 16 seventh characters, and the Gustilo-Anderson grading criteria. It also covers the documentation payers expect and the CPT codes that pair with S52.551C.

ICD-10 code S52.551C: Full description and billable status

ICD-10 code S52.551C is a valid, billable ICD-10-CM code confirmed in the CDC/NCHS ICD-10-CM web tool for fiscal year 2026. It is specific enough for claim submission without an additional specificity code.

The term “extraarticular” means the fracture does not reach the articular surface of the radiocarpal joint. That separates S52.551C from the intraarticular distal radius fractures coded elsewhere in the S52 block. Laterality is explicit in the code. S52.551 is right, S52.552 is left, and S52.559 is unspecified.

Code classification and hierarchy

S52.551C sits inside the S52 forearm fracture block, nested under several parent categories. Coders should recognize that hierarchy for sequencing and crosswalk work, because it prevents sequencing errors when several fracture codes appear on one claim.

Understanding the 7th character C in fracture codes

The seventh character in an ICD-10-CM fracture code specifies the encounter type, and choosing the wrong one is a frequent denial trigger. The S52.551 family has 16 valid seventh characters, covering each combination of fracture type and healing status. Per the CMS ICD-10-CM coding resources, the character describes the encounter being billed, not the fracture’s original classification. The grid below lays the set out along its two axes, so the logic behind 16 letters is visible at a glance.

The table below gives the full definitions. Each row names the letter, the encounter it reports, and what the note has to show.

Character C applies only to the initial encounter, which is the first time the patient receives active treatment for this injury. Once care moves to follow-up, the seventh character must change with it. Using C on a later office visit triggers an automated denial on most payer systems.

Gustilo-Anderson open fracture classification

The Gustilo-Anderson classification is the system ICD-10-CM uses to define open fracture severity. The grade decides whether the seventh character reads B or C for this injury. For S52.551C to be correct, the operative note must document a Type III fracture in one of the three subtypes.

Gustilo grading is an intraoperative determination made by the surgeon, not the coder. A coder cannot assign C independently, so the operative note must state the grade or describe one of the Type III subtypes. If the note records only an “open fracture” with no grading, query the provider before coding S52.551C.

Clinical documentation requirements for S52.551C

Payers expect the medical record to support every element of ICD-10 code S52.551C. Missing one component usually produces a specific-code denial, or a downcode to an unspecified fracture code.

The operative or emergency department note must document all of the following:

• Laterality: explicit documentation of the right radius, not just “wrist fracture” or “radius fracture”
• Articular status: confirmation the fracture is extraarticular, meaning the radiocarpal joint surface is not involved
• Open fracture confirmation: the note states the fracture is open, with a wound communicating with the fracture site
• Gustilo grade: the surgeon’s explicit classification as Type IIIA, IIIB, or IIIC, or a clinical description that supports it
• Encounter type: the visit is the initial encounter, meaning active treatment is being rendered for the first time
• Mechanism of injury: naming the cause, such as a fall or a crush injury, supports the high-energy mechanism Type III implies

Emergency departments often document laterality inconsistently, naming the “right wrist” in the chief complaint but omitting the side in the fracture assessment. Reconcile every reference in the record before selecting a laterality-specific code.

Related codes, and when one of them applies instead

The seventh-character table above already covers every encounter variant of S52.551. The codes below are the ones a coder reaches for when the side, the articular status, or the named fracture pattern is different.

A named eponym outranks the residual category. If the surgeon writes Colles’, Smith’s, or Barton’s, code the eponym group rather than S52.55.

Associated CPT codes for distal radius open fracture treatment

CPT selection follows the surgical technique, not the ICD-10 diagnosis code. The codes below appear on distal radius claims, and only one of them matches the extraarticular pattern S52.551C describes. Verify current reimbursement rates with the CMS Physician Fee Schedule lookup.

CPT 25608 and 25609 describe intra-articular fractures. Pairing either with S52.551C tells the payer the fracture both does and does not enter the joint. Where the note describes a closed reduction instead, CPT code 25600 is the counterpart to check.

For Type IIIB and IIIC injuries, CPT codes for soft tissue coverage or vascular repair usually appear alongside the fracture repair code. Validating those pairings before submission catches the conflicts a payer would otherwise deny.

Coding guidelines and common errors

The ICD-10-CM Official Guidelines for Coding and Reporting govern how fracture codes are selected and sequenced. CMS and the National Center for Health Statistics maintain them jointly, and they are reissued with each fiscal year.

The most frequent coding errors on S52.551C claims:

• Using character C for a follow-up visit: C covers only the initial encounter, when active treatment begins. Later office visits, therapy evaluations, and hardware checks take a subsequent-encounter character.
• Missing laterality: submitting S52.559C when the operative note clearly documents the right radius generates a specificity denial on most commercial payers.
• Undercoding the Gustilo grade: defaulting to character B when the note describes extensive contamination or periosteal stripping undervalues the procedure’s complexity.
• Overcoding the Gustilo grade: assigning C when the note describes a clean wound under 10 cm without periosteal stripping carries compliance risk.
• Sequencing errors: when the fracture is the reason for the encounter, it sequences as the principal diagnosis. Codes for wound contamination, vascular injury, or compartment syndrome follow as secondary diagnoses.

The AAPC ICD-10-CM code lookup carries documentation tips for this code family. Practices with recurring grading disputes between coders and surgeons benefit from a written query policy that standardizes when an addendum is required.

ICD-11 is not adopted for US billing, so ICD-11 codes do not belong on domestic insurance claims. US payers continue to require ICD-10-CM. Practices tracking rejection patterns can work from the standard denial codes. Each one names what the payer objected to and what an appeal has to answer.

How Pabau supports open fracture claim accuracy

Most orthopedic practices catch a seventh-character error after the remittance arrives. The coder assigns C, the visit turns out to be a follow-up, and the remittance comes back weeks later with a denial. By then the operative note sits in one system and the claim in another.

Pabau is practice management software that runs scheduling, charting, and billing on one record. The encounter the clinician documented becomes the encounter the claim reports. Our claims software for orthopedics submits electronically through Claim.MD and returns clearinghouse edits before the claim leaves the practice.

Every Pabau subscription includes every feature, so a single-surgeon practice validates CPT and ICD pairings the same way a multi-site group does. Any denial that still comes back lands in one worklist, with the original operative note attached.

Reduce claim denials on complex fracture encounters

Pabau’s claims tools validate CPT and ICD pairings, run clearinghouse checks, and submit electronically through Claim.MD. Orthopedic and trauma practices submit cleaner claims the first time.

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Conclusion

S52.551C is straightforward to assign and easy to lose on appeal. The difference is whether the operative note names the side, the articular status, and the Gustilo grade before the claim goes out.

Fixing the record before submission costs less than fixing it after. A query to the surgeon takes a few minutes, while a denial takes weeks to work through. Practices that write that query into their coding policy stop arguing the same case every quarter.

Pabau validates claims through Claim.MD across thousands of US payers, so open fracture claims clear clearinghouse edits before a payer sees them. Book a demo to see how Pabau handles complex trauma billing end to end.

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