ICD-10 code S52.131R: Displaced fracture of neck of right radius

Key takeaways

ICD-10 code S52.131R covers a displaced fracture of the neck of the right radius. The 7th character R marks a subsequent encounter for an open type IIIA, IIIB, or IIIC fracture with malunion.

R is the malunion character for open type III fractures. Q on the same base code means malunion after an open type I or II fracture.

P and N are the other two characters coders confuse with R. P is closed malunion, and N is open type III nonunion.

Laterality and displacement sit in the base code. S52.131 is the displaced right radial neck, and S52.132 is the left.

Practice management software like Pabau helps orthopedic practices document Gustilo grade, healing status, and encounter type at every follow-up.

ICD-10 code S52.131R is a billable diagnosis code for a displaced fracture of the neck of the right radius. Coders apply it at a follow-up visit, once an open Gustilo type III injury has healed in a poor position.

The code is valid for fiscal year 2026 under CMS ICD-10-CM guidance. It took effect on October 1, 2025, and every HIPAA-covered entity can submit it.

One letter decides whether the claim pays. S52.131Q describes the same fracture after an open type I or II injury, while R covers open type IIIA, IIIB, and IIIC. This guide walks through the full description, all 16 valid 7th characters, the Gustilo grades behind them, and the documentation each one needs.

ICD-10 code S52.131R: Quick reference

S52.131R is a specific, billable ICD-10-CM code. The table below holds every detail a coder needs before working through the supporting sections. Claims management software records those details at the encounter, so nobody reconstructs the 7th character later.

Full code description and clinical meaning

Every character in S52.131R carries a billing consequence. Misreading one segment is enough to submit the wrong code.

Each phrase in the description maps to something the physician has to write down:

• Displaced: The bone fragments have shifted out of anatomic alignment. Nondisplaced fractures of the same site move to a different base code.
• Neck of radius: The fracture sits just below the radial head. Radial head fractures take S52.12x, and shaft fractures take S52.3x.
• Right radius: Laterality is baked into the sixth character. It is not a modifier you can add later.
• Subsequent encounter: Active treatment has finished and the patient is back for follow-up care.
• Open fracture type IIIA, IIIB, or IIIC: The skin was breached and the injury was graded Gustilo type III. The code does not separate the three subtypes.
• With malunion: The fracture united, but in a non-anatomic position. That healing complication is why the visit is happening.

Laterality and displacement both live in the sixth character. S52.131 is the displaced right radial neck, S52.132 the left, and S52.133 the unspecified side. Nondisplaced fractures at the same site run from S52.134 to S52.136.

Understanding the 7th character R in fracture coding

The 7th character is the most consequential element of any S52 fracture code. Without it the code is invalid and unpayable. S52.131 carries 16 valid options, covering initial encounters, subsequent encounters, and sequela. R sits at the far end of that list, and it encodes three facts at once.

Characters I, L, and O never appear in this range. ICD-10-CM avoids letters that look like the numerals 1 and 0. The same 16-character table runs across the whole S52 forearm category, and across S42, S62, S72, S82, and S92 as well.

That shared pattern is why the letters are worth memorizing once. Read the table in threes: closed, open type I or II, then open type III. Within each healing outcome, the third letter is always the type III option.

Gustilo open fracture classification and the R character

The Gustilo-Anderson classification decides which open fracture characters are available. A coder cannot legitimately assign C, F, J, N, or R without a documented Gustilo grade in the physician notes. The CDC/NCHS ICD-10-CM tool confirms that these characters need explicit fracture-type documentation.

ICD-10-CM groups types IIIA, IIIB, and IIIC under the same characters, so the subtype never changes the code. It still has to appear in the physician documentation for medical necessity and audit purposes. A IIIC injury and a IIIA injury both bill as S52.131R at a malunion follow-up.

Malunion, nonunion, and delayed union: What each means for coding

Malunion means the fracture healed in an abnormal position. The bone ends united, which is what separates it from nonunion. That single distinction moves the 7th character from R to N.

• Routine healing (F): The fracture is uniting on schedule, with no complication documented.
• Delayed healing (J): Union is slower than expected, but callus formation is still progressing.
• Nonunion (N): The fracture has stopped healing. Imaging shows a persistent fracture line and no bridging callus.
• Malunion (R): The fracture has united, but with angulation, rotation, or shortening outside acceptable limits.

For S52.131R to hold, the record has to carry three things. The physician must state malunion in those words, not just angulation or malalignment. Imaging must support it, and the note must confirm the fracture has united.

Malunion of the radial neck often restricts forearm rotation and reduces grip strength. Those functional deficits may earn their own codes. The malunion itself is captured entirely by the R character. Corrective surgery later on carries its own procedure codes, such as CPT 20902.

When to use S52.131R: Subsequent encounter vs. initial encounter

Encounter type is one of the most audit-sensitive decisions in fracture coding. Billing an initial encounter character for a follow-up visit is a frequent trigger. The same choice sits behind S43.303A and every other injury code. The character reflects what the provider is doing now, not how long ago the injury happened.

Assign S52.131R when all of the following are true:

• Active treatment of the fracture is complete.
• The patient is back for aftercare, follow-up, or evaluation of the healing complication.
• The fracture was open and documented as Gustilo type IIIA, IIIB, or IIIC.
• Imaging and the physician note confirm malunion.
• The record shows the fracture is displaced, at the neck of the right radius.

Reach for a different code when any of these apply:

• The patient is presenting for the first time with the open type III fracture, which takes S52.131C.
• The fracture is still in active treatment, which keeps an initial encounter character.
• Malunion is suspected but not radiographically confirmed and documented.
• The fracture was closed, which makes malunion S52.131P.
• The open fracture was graded type I or II, which makes malunion S52.131Q.

ICD-10-CM hierarchy and parent codes for S52.131R

Walking the classification tree confirms that S52.131R is the most specific code available. It also gives an auditor a clean trail to follow. The 7th character only attaches once the base code is settled.

Only the last row is billable. S52.131 on its own is a non-billable parent, and a claim carrying six characters will reject.

Related codes: Laterality siblings and the S52.131 family

Two separate decisions sit behind every code in this range. First pick the base code that matches the documented side and displacement. Then pick the 7th character that matches the encounter and healing status. Codes such as S02.600D follow the same two-step logic elsewhere in the injury chapter.

Once the side and displacement are settled, the 7th character does the rest. The table below lists the siblings most often confused with S52.131R.

Use S52.133R only when the record genuinely never states a side. Verify every code against the AAPC ICD-10-CM code lookup before submitting. Billability is set per fiscal year, so check the year you are billing.

Documentation requirements for S52.131R

Seven separate elements have to appear in the record before S52.131R is defensible. Medical documentation workflows that capture each one at the point of care prevent denials before they happen. Digital clinical forms can prompt for every data point during the visit.

• Laterality: The note must say right radius. A bare radius fracture is not enough.
• Displacement: The note must say displaced. Nondisplaced fractures of this site map to the S52.134 series.
• Anatomical site: Neck of radius has to be specified. Radial head and radial shaft fractures are separate codes.
• Open fracture: Operative or emergency documentation must confirm the wound was open.
• Gustilo grade: The treating physician must record IIIA, IIIB, or IIIC. A coder cannot grade a wound from its description.
• Malunion: Imaging plus a physician statement of malunion are both required. Angulation on its own does not support R.
• Encounter type: The visit has to follow the end of active treatment, with the note reflecting aftercare or complication review.

Practices using patient record management tools that prompt for structured clinical fields capture all seven elements during the encounter. That beats chasing addenda after the visit.

Common coding errors and how to avoid them

S52.131R appears in several recurring errors that generate denials and compliance risk. Codes like S42.90XG share the same weak point. The 7th character is where coders get tripped up.

• Submitting S52.131 with no 7th character: The parent code is non-billable. A six-character claim rejects on submission, every time.
• Using Q where R belongs: Q is malunion after an open type I or II fracture. R is malunion after an open type IIIA, IIIB, or IIIC fracture.
• Using P where R belongs: P is malunion of a closed fracture. If the operative note documents an open wound, P understates the injury.
• Confusing malunion (R) with nonunion (N): N means the fracture never united. R means it united in a poor position. The documentation for each is different.
• Applying an initial encounter character to a follow-up: S52.131C covers the first visit for a type III open fracture. Using it at a six-week check is an audit flag.
• Assuming Gustilo type III from wound size: A large wound does not automatically grade as type III. Only the treating physician assigns the grade.
• Defaulting to unspecified laterality: When the side is documented, S52.131R or S52.132R is required. S52.133R is a last resort.

Clinical coding scenarios: S52.131R in practice

These four scenarios show how the letter changes with the record. They track the documentation and encounter-type decisions that sports medicine software and physical therapy EMR software workflows have to support.

Scenario 1: Eight-week malunion review. A 34-year-old returns after surgical fixation of a Gustilo IIIB open fracture of the right radial neck. The operative report documented an open wound, type IIIB, right radius neck, displaced. At eight weeks, imaging shows union with 20 degrees of angulation. The physician records malunion confirmed radiographically. The correct code is S52.131R.

Scenario 2: The same visit, but nonunion. Imaging at 12 weeks shows a persistent fracture line and no callus. The physician documents nonunion. The correct code is S52.131N, not S52.131R. The fracture never united, so malunion cannot apply.

Scenario 3: A lower Gustilo grade. Same anatomy and same follow-up timing, but the operative note graded the open wound type II. Malunion is confirmed on X-ray. The correct code is S52.131Q, because Q carries malunion for open type I and II fractures.

Scenario 4: Wrong encounter type. A patient arrives in the emergency department with a fresh open right radial neck fracture graded IIIA. The correct code for that visit is S52.131C. S52.131R would be wrong twice over, since this is an initial encounter and no healing complication exists yet.

Check every code against the official S52.131R code listing before each submission. Practices running HIPAA-compliant clinical documentation can produce the audit trail these codes require.

Approximate synonyms and clinical terms

Operative notes, discharge summaries, and referral letters rarely use code language. Treat any of these phrases as a signal to consider S52.131R, then verify each qualifying condition.

• Malunited open fracture of the right radial neck, Gustilo type III
• Displaced right radial neck fracture, open type IIIB, healed in malposition
• Subsequent care: Open comminuted right radial neck fracture with malunion
• Right proximal radius neck fracture, type IIIA open injury, malunion on follow-up X-ray
• Angulated union of an open right radius neck fracture, type III wound

None of these phrases replaces a code lookup. They work as pattern-recognition triggers only. Once the S52.131 family is in view, the 7th character still needs a full documentation review.

How Pabau supports accurate fracture coding workflows

Orthopedic and musculoskeletal practices hit the same problem at every fracture follow-up. The note has to carry laterality, displacement, Gustilo grade, and healing status, or the coder cannot defend the 7th character. Today that usually means a post-visit query and a delayed claim.

Practice management software like Pabau closes the loop inside the clinical record. Pabau ties each diagnosis code to the encounter behind it. Your billers open the supporting note before submission, so a thin operative report gets caught at the desk.

Paired with medical practice scheduling software, the record separates initial visits from follow-ups at the booking stage. Your team therefore settles the encounter type before the claim is generated, rather than correcting it after a denial.

Code fracture follow-ups right the first time

Pabau ties every diagnosis code to the encounter that supports it. Your team catches a missing Gustilo grade or healing status before the claim goes out, so open fracture follow-ups stop coming back as denials.

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Conclusion

S52.131R is narrow by design, and that is what makes it defensible. Six facts have to line up in the record: displaced, neck of radius, right side, subsequent encounter, open Gustilo type III, and confirmed malunion. If one is missing, the answer is a provider query rather than a best guess.

The letter is where the money sits. P, Q, and R all describe malunion of the same broken bone at the same stage of care. Only the fracture type separates them, and N changes the healing outcome entirely.

A follow-up template that forces the clinician to name the Gustilo grade and the healing status turns a recurring denial into a routine claim. Book a demo to see how Pabau keeps those details on every fracture follow-up note.

Continue your research

Need the same malunion character on a different forearm code? S52.355R applies R to a nondisplaced comminuted fracture of the left radial shaft.

Coding a fracture that never united? S52.532N walks through the nonunion character on a left-sided Colles’ fracture.

Working on a closed fracture with nonunion instead? S52.253K covers the K character on an ulnar shaft fracture.

Need the delayed healing character rather than malunion? S52.033J shows how J works on a displaced olecranon fracture.

Coding the ulna side of the same forearm? S52.001E covers an unspecified fracture of the upper end of the right ulna.

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