ICD code S52.311P – Right radius shaft greenstick malunion

Key takeaways

S52.311P reports a greenstick fracture of the right radius shaft that has healed with malunion, at a subsequent encounter.

The 7th character P means malunion, while S means sequela, D routine healing, G delayed healing and K nonunion.

Documentation must state the right arm, the greenstick type, the shaft site and the malunion finding itself.

Most denials come from coding S for a malunion, dropping the 7th character, or pairing acute fracture CPT codes.

The switch from D to P follows a documented finding of faulty union, not a set number of weeks.

ICD-10 code S52.311P covers a right radius that healed out of line

ICD-10 code S52.311P is a billable ICD-10-CM code for a greenstick fracture of the right radius shaft that has healed with malunion. The official descriptor reads Greenstick fracture of shaft of radius, right arm, subsequent encounter for fracture with malunion. Malunion means the bone has united, but in a faulty position.

The descriptor carries no closed or open qualifier. A greenstick fracture is incomplete and always closed, so S52.31- uses a shorter set of six 7th characters. Here’s what each character of the code tells the payer:

S52.311P needs no placeholder X or further characters. It belongs to the CMS ICD-10-CM code set and is reported for each encounter that evaluates or treats the malunion.

Choosing the 7th character: P is reserved for malunion

The 7th character on S52.311 describes the encounter, not the fracture. Only six values apply to greenstick shaft fractures, and each one maps to a different stage of care.

Guideline I.C.19.c.1 reserves A, B and C for active treatment, and D, G, K and P for routine care once active treatment ends. Malunion has its own 7th character, P, so S is not used for it.

That makes S52.311P the code for every malunion visit, whether the plan is observation, therapy or corrective surgery. S52.311S covers other late effects, and the condition code for that effect is sequenced first.

When to switch from D to P

The switch from D to P follows the provider’s finding, not the calendar. Once imaging or exam documents union in a faulty position, P applies from the next encounter for that problem. The flow below shows how one fracture moves through all six values.

Excludes notes decide which injury codes share the claim

S52.311P inherits the notes printed at category S52, so the code does carry Excludes notes. Check them before you add a second injury code to the claim.

• Excludes1: traumatic amputation of forearm (S58.-). An amputation code is never reported together with an S52 fracture code.
• Excludes2: fracture at wrist and hand level (S62.-). A carpal or hand fracture can be coded alongside S52.311P when both are present.
• Excludes2: periprosthetic fracture around internal prosthetic elbow joint (M97.4-). It is coded separately when the patient has both conditions.

What a greenstick malunion looks like in the chart

A greenstick fracture is an incomplete break in which one cortex fractures and the opposite cortex bends. It happens mostly in children, whose bones are more flexible than adult bone.

The distal radius, near the wrist, is the most common greenstick site. Fractures of the radial shaft are less frequent, which is one reason site documentation matters for S52.311P.

Malunion follows when the fracture heals with residual angulation or rotation. Children can remodel some angulation as they grow, so providers often observe a mild malunion before deciding on treatment.

A malunion visit can involve several problems, and the note should describe each one present:

• Angular deformity: visible or radiographic bowing at the old fracture site.
• Rotational malalignment: a twist in the healed shaft that changes how the forearm turns.
• Restricted pronation or supination: a functional limit that often leads to a therapy referral.
• Pain or weakness: symptoms the provider links to the malunited radius.

S52.311P has no age limit. An adult with a documented malunion of a right radial shaft greenstick fracture takes the same code, provided the record supports it.

The note has to prove five details for S52.311P

Every S52.311P claim depends on a note that supports each character of the code. The record should establish five elements:

1. Laterality: the note states the right radius or right forearm. Without it, the claim drifts to S52.319P, which payers often question.
2. Fracture type: the original fracture is documented as greenstick. If the type is unknown, S52.301P is the safer choice.
3. Site: the shaft of the radius, not the distal end, head or neck. Distal and proximal radius fractures code elsewhere in S52.
4. Malunion finding: imaging or exam shows union in a faulty position, for example residual angulation of the healed shaft.
5. Encounter purpose: the visit evaluates or treats the malunion, and the plan says so. That separates P from a routine healing check coded D.

A worked example: One fracture, three codes

Picture a child who falls from a jungle gym and fractures the right radial shaft. The case is illustrative, but the coding path is typical:

1. First visit: the provider confirms a greenstick fracture of the right radial shaft and applies a cast. That visit codes S52.311A.
2. Cast check: repeat X-rays show the fracture healing as expected. The follow-up codes S52.311D.
3. Cast removal: imaging shows the shaft united with residual angulation, and supination is limited. From this visit on, the code is S52.311P.
4. Therapy and surgical review: therapy sessions and any corrective osteotomy carry S52.311P as the diagnosis.

How the malunion claim moves

Once the coder assigns S52.311P, the claim follows a predictable path. Each step is a chance to catch an error early:

1. The coder pairs S52.311P with the visit, imaging or therapy CPT code from the note.
2. A claim scrubber checks that the code is complete and that the CPT code fits malunion care.
3. The clearinghouse validates the format and forwards the claim to the payer.
4. The payer compares the diagnosis with the service, then pays, denies or requests records.
5. The remittance advice comes back, and any denial reason code points to the fix.

CPT codes that fit a malunion encounter

S52.311P pairs with CPT codes for malunion evaluation, therapy and correction. Therapy visits often bill 97110 for exercise and 97530 for functional retraining. The table lists the pairings coders see most often.

Fracture treatment codes describe the acute injury, not malunion care. Closed and open treatment of a radial shaft fracture falls under 25500 to 25525. Codes 25600 and 25605 cover closed treatment of distal radius fractures.

Pairing any of them with S52.311P signals a mismatch, because P means the fracture has already united.

Neighboring codes that get picked in place of S52.311P

The codes pulled in error for S52.311P differ by side, encounter or fracture type. Check each one against the note before you submit.

S52.311P sits in the shaft branch of category S52

S52.311P sits in category S52, fracture of forearm, which splits fractures by bone, site and type. Knowing the boundaries prevents miscoding when old records describe the injury in plain anatomical terms.

• S52.1-: fracture of upper end of radius, including the radial head and neck.
• S52.3-: fracture of shaft of radius, the family for S52.311P.
• S52.31-: greenstick fracture of shaft of radius, split into S52.311 (right arm), S52.312 (left arm) and S52.319 (unspecified arm).
• S52.5-: fracture of lower end of radius, where distal greenstick fractures belong.

Torus, or buckle, fractures of the radius are a separate type. They code to S52.52- at the lower end or S52.11- at the upper end, never to S52.31-.

A torus fracture compresses the cortex without breaking through it, while a greenstick fracture breaks one cortex. Confirm the type in the original treating record before assigning any S52.31- code.

Each neighboring code has its own entry in our library of diagnostic codes. Compare the descriptors side by side when the record is unclear.

Common denial reasons for S52.311P claims

Denials on ICD-10 code S52.311P follow predictable patterns. A denial management review usually traces them to one of these errors:

• Coding S for a malunion: malunion takes P, because the 7th-character set for S52.311 includes a dedicated malunion value. S is for other late effects (guidelines I.C.19.a and I.C.19.c.1).
• Keeping D after malunion is found: once the note documents faulty union, routine healing no longer fits the encounter.
• Missing laterality: the claim says right arm, but the note only mentions a radius fracture. Payers deny or request records.
• Incomplete code: S52.311 without a 7th character is invalid and rejects at the clearinghouse.
• Acute treatment CPT codes: 25500 to 25525, 25600 or 25605 conflict with a malunion encounter.
• Unmeasured therapy need: therapy claims need measured range of motion and strength, not a general note about stiffness.

Before you submit an S52.311P claim, run this check

A clean claim for S52.311P clears seven checks before it leaves the practice:

• The code is complete, with P as the 7th character.
• The note names the right arm, the greenstick type and the radial shaft.
• Imaging or exam documents union in a faulty position.
• The plan says the visit evaluates or treats the malunion.
• The CPT code fits malunion care, not acute fracture treatment.
• Therapy claims include measured range of motion and strength.
• Any second injury code respects the S52 Excludes1 note.

How Pabau keeps S52.311P malunion claims clean

Malunion claims fail when the note and the claim tell different stories. A provider describes angulation in free text, and the coder still picks D or S out of habit.

Pabau, the practice management and billing platform we build, keeps structured clinical notes on each patient record. Templated assessment fields prompt the provider for side, fracture type and healing status. The coder then finds those details in one place.

Its claims management software builds each claim from that record. For US practices, the Claim.MD integration submits the claim and returns the payer response to the same record.

Your team spends less time pulling charts to answer payer requests. Fewer claims come back for a wrong 7th character, too.

Keep malunion claims clean from chart to payment

Pabau’s structured clinical notes and claims management, connected to Claim.MD, help your team document malunion and catch 7th character errors before claims go out.

Book a demo

Conclusion

S52.311P is the correct code once a right radial shaft greenstick fracture has united out of alignment. Malunion has its own 7th character, so S never stands in for it.

The work sits in the note. Document the side, the greenstick type, the shaft site and the malunion finding, and the code choice follows from the record.

Timing is the trade-off to watch. Switch to P too early and the claim outruns the evidence. Switch too late and each malunion visit goes out as routine healing.

Book a demo to see how Pabau links the malunion note to the claim, so your S52.311P claims go out right the first time.

Continue your research

Need a structured approach to medical billing compliance? Medical billing compliance guide covers the documentation and coding standards that prevent claim rejections across ICD-10 categories.

Want to understand how electronic claims move through the system? Electronic remittance advice (ERA) explained breaks down how payer responses map back to submitted diagnosis codes, including fracture claims.

Looking for a denial management workflow? Denial codes in medical billing is a reference guide to CARC denial reason codes and how to respond when a malunion claim is rejected.

Coding a malunion at another radius site? ICD-10 code S52.511P covers a displaced right radial styloid fracture that healed with malunion.

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