ICD-10 Code S52.131B: Displaced open fracture of right radial neck

Key takeaways

ICD-10 code S52.131B describes a displaced fracture of the neck of the right radius, initial encounter for open fracture type I or II

The code sits under S52.13 (fracture of neck of radius), inside the S52.1 upper end of radius block

Shaft of radius fractures belong to a separate family, S52.3, with its own displacement and pattern subdivisions

The 6th character carries laterality in S52.13, where 1 is the right radius, 2 the left, and 3 unspecified

The ‘B’ 7th character signals a Gustilo-Anderson type I or II open fracture, so coding ‘A’ instead triggers denials

Pabau’s claims management software supports accurate ICD-10-CM code capture and billing workflow documentation

ICD-10 Code S52.131B applies to a displaced fracture of the neck of the right radius, initial encounter for open fracture type I or II. It is billable and active in the FY2026 code set.

Two characters carry most of the risk on this claim. The 6th fixes laterality to the right side, and the 7th fixes the fracture as open type I or II. Open fractures at the radial neck are uncommon, so coders reach for the closed-fracture character out of habit.

This reference covers the code structure, the hierarchy above S52.131B, the full 7th character set, and the documentation each element needs.

It also covers the neck-versus-shaft mix-up behind many denials on this code. It is written for medical coders, billers, and physical therapy EMR users handling orthopedic injury encounters.

What does S52.131B mean? Breaking down the code structure

Every character in S52.131B carries clinical meaning. A coder who reads the structure can confirm the code from the operative note rather than chase documentation after submission.

Important laterality note: in S52.13 the 6th character carries both displacement and side.

Use 1 for a displaced right radial neck fracture, 2 for the left, and 3 when the record omits the side. Nondisplaced neck fractures use 4 for the right side, 5 for the left, and 6 for unspecified.

Coding 3 when the imaging report names a side invites a medical record request from the payer.

Clinical description: Displaced open fracture of the radial neck

The radial neck is the narrow segment of bone between the radial head and the radial tuberosity. It forms part of the elbow, which places S52.131B in the proximal forearm rather than the mid-forearm.

A displaced fracture means the bone fragments have shifted out of anatomical alignment. In musculoskeletal injury assessment, displacement drives both the code and the surgical decision. ICD-10-CM also defaults to displaced when the record does not state either way.

Radial neck fractures usually follow a fall onto an outstretched hand, which drives the radial head against the capitellum. Surgeons often grade them with the Mason classification, which sorts radial head and neck fractures by displacement and angulation. That grading supports the displacement element of the code.

The open designation is separate and equally important. An open fracture has a wound connecting the fracture site to the outside environment. The Gustilo-Anderson classification, the standard orthopedic grading framework, sorts open fractures by wound size, contamination, and soft-tissue injury:

• Type I: Wound less than 1 cm, minimal soft-tissue damage, clean wound, low energy mechanism
• Type II: Wound 1-10 cm, moderate soft-tissue damage, without extensive periosteal stripping
• Type III: Wound greater than 10 cm, extensive soft-tissue damage, or high-energy trauma (subdivided into IIIA, IIIB, IIIC)

S52.131B maps to Gustilo-Anderson Type I or II. Type III open fractures take the C character instead. Payers use the open fracture grade to validate the surgical approach, the antibiotic protocol, and expected resource utilization. Accurate grading in the operative note is what supports the code.

Billable status and ICD-10-CM validity for S52.131B

S52.131B is a valid, fully billable ICD-10-CM code. It is active in the FY2026 release and accepted as a principal or a secondary diagnosis, depending on the encounter.

Practices managing these claims benefit from structured claims management software that validates code-to-encounter alignment before submission. The CMS ICD-10 codes page publishes the annual FY update files that confirm active status for each code. Always verify against the FY release covering the date of service, not the date of documentation or billing.

Where S52.131B sits in the S52 code hierarchy

S52 covers every fracture of the forearm. S52.1 narrows that to the upper end of the radius, and S52.13 narrows it further to the neck. S52.131 then fixes displacement and laterality, and the 7th character fixes the encounter.

Understanding where S52.131B sits makes differential code selection faster and more defensible. The table below shows all six sibling codes under S52.13, each carrying the B 7th character:

For sports medicine software users handling acute elbow injuries, the displacement split matters. A nondisplaced radial neck fracture is often managed with early motion and a sling. A displaced one like S52.131B may need reduction or fixation, which changes the CPT codes on the same claim.

Radial neck versus radial shaft: The S52.13 and S52.3 mix-up

The single most common structural error on this code is treating S52.131B as a shaft of radius fracture. Shaft fractures live in S52.3, a different block with a different internal structure.

S52.3 begins with unspecified shaft fractures, then splits by fracture pattern rather than by displacement alone. Each pattern gets six codes of its own, covering displacement and side, which is how you land on a code like S52.355R:

Note the laterality difference between the two families. Shaft codes such as S52.301 use 1 for right, 2 for left, and 9 for unspecified. Neck codes use 1, 2, and 3. Carrying the shaft pattern across to S52.13 is how a right-sided fracture ends up coded as unspecified.

7th character encounter modifiers in category S52

The 7th character records both the fracture type, open or closed, and the stage of care. Every code in category S52 takes one of the sixteen characters below:

The B character is used only for the first encounter at which definitive treatment is rendered. Follow-up visits for wound management, sling adjustments, or hardware checks take a different character. Use E for routine healing or H for delayed healing, never a second B.

Later stages of care get their own characters. A malunion after an open type I or II fracture on the same side is S52.131Q. Once treatment is complete and the record no longer names a side, a late effect is coded S52.133S.

Excludes notes and coding conventions for forearm fracture codes

The S52 category carries two coding conventions and a set of Excludes notes. Together they decide when S52.131B applies and when a different code is required. Working from the alphabetic index alone skips them, and the claim comes back rejected.

• Coding conventions at S52: a fracture not documented as displaced or nondisplaced is coded to displaced. A fracture not documented as open or closed is coded to closed. Open fracture designations follow the Gustilo classification.
• Excludes1 at S52: traumatic amputation of forearm (S58.-). An Excludes1 note means the two conditions cannot occur together, so an amputation is coded to S58.- and never alongside S52.131B.
• Excludes2 at S52: fracture at wrist and hand level (S62.-), and periprosthetic fracture around an internal prosthetic elbow joint (M97.4). An Excludes2 note allows both codes on the same claim when both injuries are present.
• Excludes2 at S52.1: physeal fractures of upper end of radius (S59.2-), and fracture of shaft of radius (S52.3-). These are separate injuries with their own code families.
• Use an additional code for any associated open wound. Repair of that wound is reported separately, with a procedure code such as CPT 12032.

Note that S52 has no Includes note listing traumatic amputation. Amputation is an Excludes1 at this category, and treating it as an inclusion is a fast route to a rejected claim.

The CDC/NCHS ICD-10-CM web tool displays the full Includes, Excludes1, and Excludes2 hierarchy for S52 and its sub-codes. Cross-checking there before finalizing a claim takes under a minute and prevents the most common tabular-error denials.

Related and commonly confused radius fracture codes

Differentiating S52.131B from adjacent radius and forearm codes is where most coder errors occur. The table below covers the codes most often swapped for it, checked against the AAPC Codify ICD-10-CM lookup.

When both the radius and the ulna are fractured in the same forearm, assign a separate code for each bone. ICD-10-CM has no combination code for a both-bone forearm fracture. An upper-end ulna injury seen at a later visit, for example, codes to S52.001E.

Documentation requirements for S52.131B

Most claim denials for S52.131B trace back to a documentation problem rather than a code error. The code is defensible only when the clinical record supports each of its defining elements. Solid patient record documentation makes that straightforward.

Five elements must be present in the documentation before submitting S52.131B:

1. Fracture site: the record must name the neck of the radius. An unqualified proximal radius fracture supports only S52.101-, and a mid-shaft injury belongs in S52.3-. Imaging reports usually give the level, so cite the specific report.
2. Displacement status: displaced should be documented explicitly. Wording such as angulation or overriding fragments supports it. A bare radial neck fracture defaults to displaced under the S52 convention, but explicit wording is far safer under audit.
3. Fracture type (open or closed): the operative report or ED note must confirm a wound communicating with the fracture site. Gustilo-Anderson grading in that note validates the B character over C.
4. Laterality: the record must state right or left. S52.131B is the right-sided code, so a note reading only radial neck fracture cannot support it. Unspecified (S52.133B) is a last resort, not a default.
5. Encounter type: initial encounter documentation must show this is the first episode of definitive care. Later visits need notes covering healing progress, complications, or hardware management.

The same five-element principle carries across every injury code in Chapter 19. Practices that build the checklist into their pre-claim review catch the missing element while the chart is still open.

Common coding errors with radial neck fracture codes

Five mistakes account for the majority of S52.131B claim problems. Each is preventable with a structured pre-submission review:

• Coding it as a shaft fracture: S52.131B covers the neck of the radius. A mid-shaft injury belongs to S52.3-, which has its own pattern and laterality characters. Read the imaging report for the exact level before picking the block.
• Wrong 7th character: using A (closed fracture) when the record documents an open wound. Look for open wound, laceration, or wound communication in the operative report. The choice between A and B affects reimbursement, surgical validation, and antibiotic claims.
• Reading the 6th character as unspecified: in S52.13 the character 1 means the right radius. Unspecified is 3. Coders who carry the wrist or shaft numbering across can turn a left-sided fracture into a right-sided one.
• Confusing Type I or II with Type III: a wound over 10 cm or with extensive soft-tissue damage is Type III. That grade takes the C character instead, so S52.131C applies whenever the surgeon documents Gustilo IIIA, IIIB, or IIIC.
• Reusing B for follow-up visits: the B character applies only to the initial encounter for active treatment. Wound checks and hardware reviews take E for routine healing. Reusing B flags a duplicate encounter and triggers audit review.

Every one of these is caught by reading the tabular entry rather than the alphabetic index. The tabular puts the sibling codes side by side, so the level, the side, and the grade are visible at once. Open fractures elsewhere around the elbow follow the same 7th character pattern, as S42.436B shows on the humeral side.

How practice management software keeps fracture coding accurate

Most S52.131B errors start upstream of the coder. The imaging report names one level, the operative note names another, and the documented side never reaches the structured record. By the time the claim is built, the coder is reconstructing the encounter from fragments.

Practice management software like Pabau keeps the diagnosis, the encounter type, and the supporting clinical notes attached to the same patient record. Coders can open the imaging report and the operative note without leaving the claim. The level, the side, and the Gustilo grade all sit in one view.

Pabau’s claims management tools flag incomplete encounters before submission. A missing laterality or an unconfirmed open fracture grade surfaces in the practice rather than at the payer.

Reworking a claim after rejection costs far more. Reporting then shows which diagnosis codes drive your rejections, so you can fix the documentation pattern instead of reworking claims one by one.

The outcome is a shorter path from encounter to payment, with fewer medical record requests along the way.

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Conclusion

S52.131B has a narrow application. It covers a displaced fracture of the neck of the right radius, at the initial encounter. The fracture must be open, graded Gustilo type I or II. Anything outside that description belongs to another code.

Three details decide the claim: the level of the fracture, the side, and the open fracture grade. Get those three into the record and the code follows without argument. The neck-versus-shaft distinction is worth a second look on every one of these claims.

Pabau’s claims management tools help orthopedic and sports medicine practices build the documentation checkpoints that catch these errors before a claim reaches the payer. Book a demo to see how that works in a live clinical workflow.

Continue your research

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Ruling out a rotator cuff tear after the same fall? Drop arm test covers how to perform the assessment and record the result.

Coding a shoulder dislocation from the same trauma? S43.303A sets out the laterality and encounter rules for the initial visit.

Handling a combined radius and ulna injury? S52.033J shows how the ulna side of a forearm fracture is coded at a later stage.

Running rehab for patients recovering from fractures? Physiotherapy clinic management software covers the scheduling and documentation needs of rehab practices.

Frequently asked questions

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