ICD code S52.591C – Other fractures of lower end of right radius

Key takeaways

S52.591C covers an other fracture of the lower end of the right radius, graded Gustilo IIIA, IIIB, or IIIC. It applies at the initial encounter only.

The code sits in S52.5, fracture of lower end of radius. S52.291C sits in S52.2 and describes the ulna shaft instead.

The 7th character C is exclusive to open fractures graded Gustilo type IIIA, IIIB, or IIIC. All three subtypes share that one character.

Coders never assign the Gustilo grade themselves. Where the record states an open wound but no grade, ICD-10-CM sends you to B, not C.

Practice management software like Pabau keeps the coded chart and the outgoing claim in one system, so the biller never re-keys the codes.

ICD-10 code S52.591C, summed up in one table

Start with the lookup. The reasoning behind each row follows underneath.

What each part of the code tells the payer

Read the code left to right and each segment narrows the injury a little further. Misread one segment and you have described a different fracture.

The “other fracture” designation at the 5th character means the pattern does not meet the criteria for any named distal radius subcategory.

It is not a Colles’ fracture (S52.53-), a Smith’s fracture (S52.54-), a Barton’s fracture (S52.56-), or a radial styloid fracture (S52.51-). Coders in orthopedic and trauma settings meet this when the surgeon describes the morphology in detail but never names it.

The injury this code was written for

Distal radius fractures are among the most common fractures seen in adults, according to the American Academy of Orthopaedic Surgeons (AAOS).

Most are closed injuries. S52.591C represents the subset that presents as an open wound, meaning bone has breached the skin or the wound communicates directly with the fracture site.

A worked example. Someone comes off a bike at speed and lands on the right wrist. Imaging shows a distal radius fracture that is not a Colles’, Barton’s, Smith’s, or styloid pattern. The surgeon documents an open wound and grades it Gustilo IIIB. Surgery happens the same day, so this is the initial encounter. That record supports S52.591C, and only that record does.

• Open vs closed: a closed fracture of the same site and pattern uses 7th character A (initial) or D (subsequent), never C.
• Laterality required: right radius specifically. Left uses S52.592C, and unspecified uses S52.599C.
• Active treatment, not routine follow-up: the patient is having surgery, casting, or definitive management at this visit. Routine monitoring of a healing fracture does not qualify.
• Gustilo documentation drives the character: the physician must document the Gustilo grade. A coder cannot infer the grade from wound size or wound description alone.

The 7th character C does two jobs at once

The 7th character carries two facts in a single letter. It records whether the fracture is open or closed, and it records the phase of care. C means an open fracture of Gustilo grade IIIA, IIIB, or IIIC, seen at an initial encounter.

So you need both facts before you can choose a letter, and both have to come off the record. That logic runs through the whole S52 family, and through every traumatic fracture chapter in the code set.

Gustilo grades decide between B and C

Gustilo and Anderson published this classification in the Journal of Bone and Joint Surgery in 1976. It grades open fractures by wound size, soft tissue injury, contamination, and bone involvement.

ICD-10-CM does not separate types IIIA, IIIB, and IIIC at the 7th character level, so all three map to character C.

Important: an open type I or II fracture takes 7th character B instead. Only types IIIA, IIIB, and IIIC take character C, and assigning it to a type I wound will not survive a documentation audit.

ICD-10-CM also tells you what to do when the grade is missing. Where the record documents an open fracture but no Gustilo type, the guidelines send you to the type I or II character. At an initial encounter that letter is B rather than C, because the default runs down and never up.

Put those rules end to end and the whole choice comes down to three questions about the record.

Pick the 7th character that matches the visit

The table below covers the whole treatment continuum. It runs from initial active treatment through healing complications and late effects.

Choosing the right letter means knowing the care phase the physician documented at that visit.

Where S52.591C sits, and what sits next to it

Laterality and fracture specificity decide which sibling code applies. When documentation does not state right or left, use the unspecified code. Never guess, and never default to right.

Category S52 carries two exclusion notes that matter on trauma claims. Traumatic amputation of the forearm is an Excludes1 note, so S58.- never appears alongside a code from S52.

Fracture at wrist and hand level is an Excludes2 note, so a carpal or metacarpal fracture from the same accident is coded separately with S62.-.

S52.591C and S52.291C are not the same bone

These two codes share a 7th character and look almost identical on a claim line, but they describe different bones. The 4th character is the whole difference, and payers read it.

If the operative note describes a wrist injury and distal radius fixation, S52.591C is the code. S52.291C belongs to subcategory S52.2, fracture of shaft of ulna, and describes an ulna shaft injury in the middle of the forearm.

Sending an ulna shaft diagnosis with a distal radius procedure code invites a medical necessity denial on the first pass.

Five guideline rules that decide this code

CMS and the National Center for Health Statistics maintain the ICD-10-CM Official Guidelines for Coding and Reporting.

Five of those rules bear directly on this code:

• Open must be documented: according to the CMS ICD-10-CM guidelines, a fracture not documented as open or closed defaults to closed. The open designation has to come from the physician.
• Displaced is the default: a fracture not documented as displaced or nondisplaced is coded as displaced. That does not change the code here, because S52.59- does not split on displacement.
• Ungraded open wounds default down: where the Gustilo type is not specified, ICD-10-CM assigns the type I or II character. At an initial encounter that means B, not C.
• Highest specificity documented: laterality is coded to what the record states. S52.599C is only acceptable when the physician’s record genuinely does not identify a side.
• Parent codes do not bill: S52, S52.5, and S52.59 are not valid on a claim. The payer edit rejects a code shorter than the full seven characters.

Those five rules collapse into one habit at the desk. Confirm wound type, Gustilo grade, laterality, and care phase before the claim goes out, not after a denial arrives.

What the record must say before you code it

Five elements have to appear in the physician’s own words before this code is defensible. If any one is missing, the correct move is a physician query, not an assumption.

Five coding errors that get these claims denied

These five turn up again and again on S52 remittances. Each one is cheap to catch beforehand and expensive to fix afterwards.

• Wrong bone: reaching for S52.291C, which is an ulna shaft fracture, when the record describes a distal radius injury. The two codes differ by one digit and by several centimeters of forearm.
• Laterality error: assigning S52.592C when the documentation says right, or the reverse. Read the operative report, not the intake sheet.
• 7th character mismatch: using C on a routine follow-up visit when the correct character is F. Same fracture, different visit, different code.
• Gustilo grade not documented: assigning C when the note says only “open fracture”. Without a stated grade the guidelines send you to B.
• Named pattern overlooked: using the “other” code when the surgeon named a Colles’, Smith’s, or Barton’s fracture. Those have their own subcategories and their own codes.

Each of these comes back on the remittance as a specific rejection, and the denial codes tell you which one you hit. Flag S52 claims for a documentation review before they leave the practice, and most of these never reach a payer at all.

The CPT codes that pair with this diagnosis

S52.591C is a diagnostic code only. You report the surgical work separately with CPT codes. The pairings below reflect the open nature of the injury, because closed reduction alone rarely suits a Gustilo type III wound.

Where these pairings usually go wrong

The split between 25607 and 25608-25609 is the one coders get wrong most often. 25607 covers an extra-articular fracture. 25608 and 25609 need the fracture to enter the radiocarpal or distal radioulnar joint, and the number of fragments fixed then chooses between them.

Check payer-specific National Correct Coding Initiative edits before these combinations go out.

Debridement is the other common trap. Because an open fracture is present, the 11010-11012 family applies rather than the 11042-11047 wound debridement codes.

Depth decides which one. Code 11010 covers skin and subcutaneous tissue, 11011 adds muscle and fascia, and 11012 goes through bone. Some payers still bundle the debridement into the fracture repair, so confirm the edit before billing both on the same date of service.

If soft-tissue coverage later calls for a skin substitute, that product bills on its own line. HCPCS code Q4104 is reported per square centimeter of the applied wound area. The claim also needs an application code from 15271-15278, or the product line triggers a technical denial.

External cause codes belong on this claim too

A Gustilo type III wrist fracture is almost always a high-energy injury, so Chapter 20 external cause codes usually belong on the claim. They are always secondary. An external cause code is never the first-listed diagnosis.

These codes carry weight on trauma claims. Workers’ compensation and auto carriers often route the file on the status and place codes alone. A missing Y99 can therefore send a payable claim to the wrong payer.

The 7th character moves when the patient does

S52.591C is a one-visit code. Once the patient moves out of active treatment, the 7th character has to move with them. The rest of the code stays exactly the same.

• Routine healing: S52.591F, for a follow-up visit where the open type III fracture is healing as expected.
• Delayed healing: S52.591J, when the physician documents that union is slower than anticipated.
• Nonunion: S52.591N, once the surgeon documents that the fracture has failed to unite.
• Malunion: S52.591R, when the fracture has united in a poor position.
• Sequela: S52.591S, for a late effect such as post-traumatic stiffness, coded with the condition the sequela caused.

Those five all keep the S52.591 stem because the fracture pattern has not changed. A right-sided Colles’ fracture with the same open type III wound and a nonunion takes S52.531N instead.

Sequela coding has one rule that catches people out. List the condition resulting from the injury first, then S52.591S second. Never put the residual condition and the acute injury code on the same claim line.

How an S52.591C claim moves from note to payment

The code is one stop on a longer route, and most of the trouble happens at the hand-offs. Here is the path a single open wrist fracture takes:

1. The operative note. The surgeon records the site, the side, the pattern, the wound grade, and the treatment given that day.
2. Coding. You assign S52.591C, the external cause codes, and the surgical CPT code, then sequence the injury first.
3. Charge entry. The CPT line picks up an RT modifier for the right wrist, which has to agree with the diagnosis.
4. The scrubber. Front-end edits catch missing characters, laterality conflicts, and bundled pairs before the claim leaves.
5. The payer. Medical necessity edits compare diagnosis to procedure, so a wrist diagnosis with a shaft procedure stops here.
6. The remittance. Payment arrives, or a denial arrives with a reason code naming what failed.

Two hand-offs cause most rejections. One is the move from the operative note to the coding sheet, where laterality and the Gustilo grade get dropped. The other is the move from coding to charge entry, where the diagnosis says right and the modifier says left.

Run this check before you submit

Seven lines, and each takes seconds against the chart. Work down them before the claim leaves the practice.

• The note names the lower end of the radius, not the shaft and not the ulna.
• The note says right, and the CPT line carries an RT modifier.
• The pattern is described but never named as Colles’, Smith’s, Barton’s, styloid, or intraarticular.
• The physician wrote “open” and graded the wound IIIA, IIIB, or IIIC.
• The visit is active treatment, not a routine healing check.
• The external cause, place, activity, and status codes sit on the claim as secondary.
• Bundling edits are checked for any debridement billed alongside the fixation.

Where to verify the code

Codes in the S52 family stay stable across recent fiscal years, but confirm the annual update before you bill. Three sources settle almost every question.

• The CDC/NCHS ICD-10-CM web tool is the authoritative tabular list for the applicable fiscal year, including Excludes notes.
• The AAPC Codify ICD-10-CM lookup gives searchable code descriptions and the notes attached to each subcategory.
• The WHO ICD-10 browser covers the international classification structure from which ICD-10-CM is derived.

How Pabau keeps the coded chart and the claim in step

In a typical practice the side of the injury and the wound grade are written once, in the operative note. Then someone types them again by hand at billing.

That second keystroke is where a distal radius code quietly becomes an ulna shaft code, and the denial turns up three weeks later.

Practice management software like Pabau keeps the clinical record and the claim in one system. The operative note, the imaging report, and the codes stay attached to the same encounter. Your biller then works from the chart instead of a summary sheet.

Pabau’s claims management software then sends the claim electronically through a regional clearinghouse and runs eligibility checks before the visit. It does not grade wounds or crosswalk codes for you, and no software should.

What it removes is the re-keying and the chase, so the codes your surgeon documented are the codes the payer receives.

Keep orthopedic claims clean the first time

Pabau holds the operative note, the codes, and the claim on one encounter, submits electronically, and checks eligibility before the visit. See how it handles your fracture billing in a live demo.

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Conclusion

S52.591C is not a hard code to assign. It is a hard code to defend, because four of its five elements live in someone else’s handwriting. The site, the side, the pattern, and the grade all come from the surgeon, and you own only the sequencing.

So the work moves upstream. Query the grade while the patient is still in the building, rather than three weeks later against a denial. A query costs an hour. Reworking a denied type III claim costs far more, plus the days it adds in accounts receivable.

The near miss is the one to watch. S52.291C sits one digit away and describes an ulna shaft, and a payer reads that as a different injury. If your fracture claims keep coming back for documentation, book a demo. You will see how Pabau keeps the operative note and the claim on one record.

Continue your research

Coding a different distal radius pattern? S52.355C covers the nondisplaced comminuted fracture of the lower end of the radius.

Looking at a buckle fracture instead? S52.529D covers a torus fracture of the lower end of the radius at a follow-up visit.

Billing debridement alongside the fixation? CPT code 11011 covers open fracture debridement that reaches muscle and fascia.

Chasing a rejection on a fracture claim? Denial management in healthcare walks through resolving ICD-10 rejections and stopping the repeats.

Preparing for a payer audit? Medical billing compliance sets out the documentation standards that hold up under review.

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