ICD-10 Code S52.355C: Nondisplaced Comminuted Fracture Lower End Radius

Key Takeaways

ICD-10 Code S52.355C describes a nondisplaced comminuted fracture of the lower end of the radius, open type IIIA, IIIB, or IIIC, initial encounter – it is a fully billable 7-character diagnosis code.

The 7th character C covers all three Gustilo Type III subtypes (IIIA, IIIB, IIIC); ICD-10-CM does not split them further, so the treating physician’s documented subtype determines clinical severity but not the code itself.

Wrong 7th character selection is the top audit trigger for this code – use A (closed) or B (open Type I/II) only when clinical documentation explicitly supports those classifications.

Pabau’s claims management software integrates with Claim.MD to validate S52.355C submissions, check laterality documentation, and flag 7th character mismatches before claims reach the payer.

Open fractures of the distal radius rank among the most complex coding scenarios in orthopedic billing. A wrong 7th character on a single claim can trigger a payer audit, a denial, or a take-back – even when the clinical documentation is otherwise flawless. Medical billing for open fractures demands precise code selection, and S52.355C is one of the codes where that precision matters most.

This reference covers the full code descriptor, 7th character table, Gustilo classification mapping, laterality guidance, companion CPT codes, and the most common documentation errors coders encounter with ICD-10 Code S52.355C.

ICD-10 Code S52.355C: quick reference

ICD-10 Code S52.355C is a billable diagnosis code in the ICD-10-CM system, effective for encounters from October 1, 2015 onward. The full clinical descriptor is: Nondisplaced comminuted fracture of the lower end of the radius, open type IIIA, IIIB, or IIIC, initial encounter.

Breaking down ICD-10 Code S52.355C character by character

Each character in ICD-10 Code S52.355C encodes a specific clinical attribute. Coders who understand the structure can spot documentation gaps before submission rather than after a denial arrives.

The distal radius – the lower end of the radius bone – is the most common fracture site in the human body across all age groups, according to the CDC/NCHS ICD-10-CM reference tool. The comminuted pattern (S52.35) indicates high-energy trauma, which commonly produces the bone fragmentation that pushes these injuries into open fracture territory.

Understanding the 7th character for ICD-10 Code S52.355C

The 7th character is where most billing errors originate. According to the CMS ICD-10-CM coding guidelines, the encounter type designation is a clinical determination – not simply a count of how many times the patient has been seen. “Initial encounter” applies throughout the entire active treatment phase, even if the patient has had multiple visits with the same provider. Coders should assign the 7th character based on the nature of the care being provided, not the visit sequence.

For S52.355, all valid 7th characters are listed below. Understanding 7th character coding in ICD-10-CM across code categories helps coders apply these rules consistently.

Character C is the one that applies to ICD-10 Code S52.355C: an initial encounter for an open fracture classified as Gustilo Type IIIA, IIIB, or IIIC. All three subtypes collapse into the single character C because ICD-10-CM does not distinguish between them at the code level.

Gustilo-Anderson classification and ICD-10 Code S52.355C

The Gustilo-Anderson classification is the clinical framework physicians use to grade open fracture severity. Coders must rely entirely on the physician’s documented subtype – they cannot infer Gustilo type from operative notes or radiology reports alone. This is a sensitive claim area: determining whether a fracture is Type IIIA, IIIB, or IIIC is a clinical judgment that belongs to the treating orthopedic surgeon.

Type IIIC carries a substantially different clinical trajectory from IIIA, with potential for amputation when vascular repair fails. ICD-10-CM groups all three under character C because the system captures the open fracture severity category rather than the individual management pathway. Surgeons treating sports medicine and orthopedic injuries should document the Gustilo subtype explicitly – “Type IIIA open fracture” in the operative note, not just “high-energy open fracture.”

S52.355C code hierarchy: parent and sibling codes

ICD-10 Code S52.355C sits within a structured hierarchy. Understanding the parent and sibling codes helps coders navigate laterality documentation requirements and choose between displaced and nondisplaced variants. Reviewing related ICD-10 diagnostic coding guides can also build fluency with the S52 hierarchy logic.

Note that S52.355 codes the left side. S52.354 is the right-side equivalent; S52.359 covers unspecified laterality. Coders should query the provider if laterality is not documented rather than defaulting to unspecified, which loses clinical specificity and can trigger additional payer scrutiny.

Coding guidelines for ICD-10 Code S52.355C: what ICD-10-CM requires

The ICD-10-CM Official Guidelines for Coding and Reporting (published by CMS and NCHS, maintained under the authority of the ICD-10 encounter type selection guidance framework) establish the governing rules for fracture coding. Three guidelines are most relevant to ICD-10 Code S52.355C.

• Active treatment = initial encounter: Per ICD-10-CM guideline I.C.19.a, character A (or B or C for open fractures) applies for the entire duration of active treatment. A patient who has their fracture surgically repaired at a second visit still gets character C if they are in active treatment.
• Subsequent encounter begins at routine aftercare: Once active treatment ends and the patient is in the monitoring or rehabilitation phase, switch to the appropriate subsequent encounter character (D through R depending on fracture type and healing status).
• Sequela (character S) is distinct: Code S applies when the patient presents with a late effect or residual condition that results from a previous fracture – for example, post-traumatic arthritis of the wrist following a distal radius fracture. The sequela code is used alongside a separate code for the nature of the sequela.
• Laterality must be coded to highest specificity: If the physician documents left radius fracture, use S52.355C (left). If right, use S52.354C. Use S52.359C (unspecified) only when laterality genuinely cannot be determined from available documentation.
• Displacement status is physician-determined: Nondisplaced means the fracture fragments have not shifted from anatomical alignment. Coders must not infer displacement status from imaging alone – the treating physician’s documentation controls code selection. If not documented, code to unspecified rather than nondisplaced.

Submitting a clean claim for open fracture diagnoses requires that all four elements (fracture site, pattern, displacement, and encounter type) are explicitly documented in the clinical record before claim submission.

Companion CPT codes for distal radius fracture treatment

ICD-10 Code S52.355C is a diagnosis code – it identifies the condition. Procedure codes (CPT) are assigned separately to capture the treatment rendered. The CPT codes paired with this diagnosis depend entirely on what the physician did, not on the diagnosis code itself. Pabau’s claims management software helps orthopedic and surgical billing teams pair diagnosis and procedure codes accurately before submission via the Claim.MD clearinghouse integration, which validates CPT-to-ICD-10 pairings against active payer rules.

CPT 25609 is particularly relevant for ICD-10 Code S52.355C given the comminuted fracture pattern. A comminuted fracture, by definition, involves three or more bone fragments, which typically meets the threshold for 25609 when open reduction is performed. Verify with companion CPT coding reference materials and the AMA CPT manual for the current code year. Payer policies on CPT-to-ICD-10 pairing vary, and the billing team should verify payer-specific requirements before submission.

Common coding errors for ICD-10 Code S52.355C

Open fracture codes generate a disproportionate share of orthopedic billing denials. The four errors below account for most claim rejections on ICD-10 Code S52.355C. Understanding denial management in healthcare helps billing teams resolve these quickly when they do occur.

• Wrong 7th character for fracture type: Assigning C when the operative note documents a Type I or II open fracture, or assigning B when the physician clearly documents Type III. Always confirm Gustilo type from the physician’s documentation before assigning character B or C.
• Using C for a closed fracture: Character C is only valid when there is an open wound. A high-energy distal radius fracture without skin breach is still coded with character A (closed). Coding C on a closed fracture is a medical necessity mismatch that triggers denial and potential fraud flags.
• Defaulting to nondisplaced without documentation: If the physician has not explicitly documented that the fracture is nondisplaced, coders should not assume it. The ICD-10-CM guidelines direct coders to the unspecified displacement code when documentation is unclear – not to nondisplaced.
• Omitting or estimating laterality: Using the unspecified laterality code (S52.359C) when laterality is actually documented is a specificity error. Using the wrong side (coding left when the injury is right) is a factual error. Both can result in denial codes in medical billing that require corrected claims.

Sequela, nonunion, and malunion: follow-up coding

Patients with Type III open distal radius fractures often require extended follow-up care, and the ICD-10 Code S52.355C framework shifts as treatment progresses. Coders managing physical therapy or orthopedic follow-up encounters need to transition from character C to the appropriate subsequent encounter or sequela character as clinical status changes.

Nonunion (character P for Type III open) and malunion (character R) require explicit physician documentation. Coders should not infer nonunion from delayed healing alone; the physician must document the failure of union for character P to apply. Sequela coding (character S) is used only when the patient presents for a condition that is the direct consequence of the original fracture, not for the fracture itself. Review ICD-10 encounter type selection guidance to reinforce these distinctions across code families.

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Conclusion

ICD-10 Code S52.355C is one of the most documentation-dependent codes in orthopedic billing. Four attributes must all be explicitly documented before the code is valid: the fracture is comminuted, it affects the lower end of the radius, it is nondisplaced, and the open wound is Gustilo Type III. Miss any one of those and the code is unsupported – and so is the claim.

Pabau’s revenue cycle management tools help orthopedic and surgical billing teams catch these gaps before submission, not after denial. To see how Pabau handles ICD-10 coding workflows and claim validation end to end, book a demo.

Continue your research

Need to validate ICD-10 fracture codes before submission? Claim.MD clearinghouse overview covers how electronic claim validation works and why payer edits catch code mismatches before adjudication.

Want to understand denial patterns for orthopedic claims? Medical billing compliance guide explains the regulatory framework and audit triggers that affect open fracture and surgical claim submissions.

Looking for a complete IVF or fracture coding workflow? IVF CPT codes reference illustrates how companion procedure-plus-diagnosis coding frameworks apply across surgical specialties.

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