ICD code S92.415K – Nondisplaced proximal phalanx fracture, left great toe

Key takeaways

S92.415K codes a nondisplaced proximal phalanx fracture of the left great toe at a subsequent encounter where nonunion is documented.

S92.4 is the great toe fracture category. Fractures of the second through fifth toes are coded under S92.5, so S92.415K never applies to a little toe.

The ‘K’ 7th character is valid only for subsequent encounters. The treating provider must document failed bone healing, supported by imaging such as a plain radiograph.

Denials most often follow from using K when imaging does not confirm nonunion. Submitting K on what should be an initial encounter (A) or a routine subsequent encounter (D) is the other common cause.

Pabau’s claims management software helps practices track encounter type across visits and flag 7th character mismatches before claim submission.

ICD-10 Code S92.415K: Definition, billable status, and quick-reference data

ICD-10 Code S92.415K is a valid, billable ICD-10-CM diagnosis code for fiscal years 2025 and 2026.

Both the CDC/NCHS ICD-10-CM web tool and AAPC Codify confirm it as active. Its full official descriptor is: Nondisplaced fracture of proximal phalanx of left great toe, subsequent encounter for fracture with nonunion.

The code sits in subcategory S92.4, which covers fractures of the great toe only. Fractures of the second through fifth toes belong to S92.5 instead. Both subcategories sit under the ICD-10-CM chapter for injuries to the ankle and foot (S90-S99). S92.415K carries no Type 1 or Type 2 Excludes notes that would restrict its use alongside other foot injury codes.

Code descriptor breakdown: Anatomy and clinical meaning of S92.415K

Every component of ICD-10 Code S92.415K carries a specific coding obligation. Misreading any element introduces laterality or encounter-type errors that result in denials. The table below dissects the descriptor term by term, drawing on CMS ICD-10-CM coding guidance and standard anatomical references.

The great toe has two phalanges rather than three, so its proximal phalanx sits between the first metatarsal head and the distal phalanx. Most nondisplaced fractures here follow direct trauma, such as stubbing the toe or dropping a weight onto the forefoot. Nondisplaced fractures are usually managed conservatively at first. That is why nonunion carries clinical weight on this code. A fracture that looked stable can fail to consolidate, and the great toe takes the push-off load at every step.

What the ‘K’ seventh character means

The ‘K’ seventh character designates a subsequent encounter for a fracture with nonunion. That definition comes from the ICD-10-CM Official Guidelines for Coding and Reporting, Section I.C.19.a. Nonunion means a fracture has failed to achieve bony union within the expected healing timeframe. Imaging usually shows absent or arrested callus formation. Two adjacent characters are easy to confuse with K: delayed healing (G) and malunion (P). The seventh character rules work the same way across every fracture category, so knowing them prevents most assignment errors here.

The full 7th character set for S92.415- is fixed by the ICD-10-CM tabular list. Each character signals a different clinical and administrative status:

K vs G: Delayed healing (G) means healing is progressing but slowly. Nonunion (K) means healing has stopped. The clinical distinction requires provider documentation, not coder interpretation. If the note says “slow healing” without confirming failed union, G is the appropriate character. K requires explicit documentation of nonunion, typically supported by radiographic evidence of no callus progression.

K vs P: Malunion (P) means the fracture has healed, but in a faulty position. Nonunion (K) means it has not healed at all. These require entirely different clinical interventions and must never be interchanged. The decision chart below runs the same choice in one pass, from what the record documents to the code it supports.

S92.415K vs adjacent codes: Choosing the right code

S92.414K is the direct right-side equivalent of S92.415K. It codes a nondisplaced fracture of the proximal phalanx of the right great toe at a subsequent encounter with nonunion. Laterality errors between S92.414K and S92.415K are among the top denial causes for this code family. The comparison table below covers the most commonly confused adjacent codes, informed by the AAPC Codify ICD-10-CM lookup.

Documentation requirements for S92.415K

Documentation requirements for S92.415K are more demanding than those for routine subsequent fracture codes (S92.415D), because nonunion requires clinical evidence beyond the provider’s note alone. Insufficient documentation is the leading cause of claim denial for this code. All six elements below belong in the record before the code is assigned. Meeting them also supports submitting a clean claim on the first pass.

• Encounter type: The note must clearly establish this is a follow-up visit, not the initial injury encounter. Language such as “follow-up for left toe fracture” or “return visit for known fracture” is sufficient.
• Laterality: The left side must be documented explicitly. “Foot” or “lower extremity” alone does not satisfy laterality requirements under ICD-10-CM.
• Digit identification: The great toe must be named. “Toe fracture” without digit specification does not support S92.415K, and a lesser toe points to S92.5 instead.
• Phalanx level: The provider must identify the proximal phalanx specifically. A distal phalanx fracture of the great toe uses a different base code, S92.42-.
• Displacement status: The record must confirm nondisplacement. Imaging reports describing aligned or non-displaced fragments satisfy this requirement.
• Nonunion confirmation: This is the critical element. The record needs a plain radiograph report showing absent or arrested callus formation, or a persistent fracture line without bridging. A provider notation of “fracture nonunion confirmed by imaging” also works. A clinical impression alone (“appears not healed”) is generally insufficient for payer purposes without radiographic correlation.

Which CPT codes pair with S92.415K?

CPT code selection for S92.415K claims depends on what intervention is performed at the subsequent encounter. Conservative management, surgical intervention, and physical therapy visits each pull from different code families. The pairings below reflect standard billing practice. Payer policies on medical necessity vary by jurisdiction, so verify coverage before submission.

CPT separates the great toe from the lesser toes, so S92.415K pairs with 28490 or 28495 rather than 28510 or 28515. The manipulation split matters too. If the procedure at the subsequent encounter involves no active reduction, 28490 is correct. Billing 28495 without documented manipulation is an audit flag. Confirm current CPT descriptor language against the AMA CPT manual for the service year, since descriptors are refined annually.

Payer requirements and pre-authorization for fracture nonunion claims

Medicare and major commercial payers treat fracture nonunion claims differently from routine subsequent encounters. The ‘K’ seventh character signals a complication of healing, which most payers classify as a higher-scrutiny claim category. Practices submitting S92.415K should route claims electronically through Claim.MD, the US clearinghouse partner used by practice management software like Pabau. Claim.MD processes over 4,000 payers and supports real-time eligibility verification before submission. The claims management software built into Pabau checks code-level pairing rules before the claim leaves the practice.

• Imaging documentation: Medicare typically requires a radiology report confirming nonunion. A Local Coverage Determination (LCD) from the relevant Medicare Administrative Contractor (MAC) may specify minimum imaging requirements. Check your MAC’s LCD for “fracture nonunion” before submitting.
• Conservative treatment failure: Commercial payers often require evidence that conservative management was attempted before surgical intervention for nonunion will be authorized. Document immobilization, offloading, or physical therapy in the record.
• Time since injury: While ICD-10-CM does not specify a minimum time threshold for nonunion, payers may apply clinical benchmarks. Toe fractures are generally expected to show callus within 6 to 8 weeks; claims for nonunion within that window may attract review.
• Pre-authorization triggers: Surgical CPT codes (28505, bone grafting) paired with S92.415K commonly require prior authorization. Confirm payer requirements before scheduling the procedure, not after.

Common claim denial reasons for S92.415K and how to avoid them

Denials on S92.415K claims follow predictable patterns. Most trace back to two root causes: incorrect 7th character selection and insufficient documentation supporting nonunion. Reading the remittance against the standard denial codes in medical billing tells a billing team which of the two it is. Catching either one before submission costs far less than appealing after the fact.

ICD-9-CM crosswalk for S92.415K

ICD-10 Code S92.415K has no direct one-to-one ICD-9-CM equivalent. ICD-9-CM lacked the 7th character system for encounter type and healing status. Nonunion, delayed healing, and sequela were not separately codeable within most injury categories. The approximate ICD-9-CM predecessor codes for this clinical scenario are shown below. These are useful for practices reconciling legacy records or historical data analysis, not for current billing. For current claim submissions, always use ICD-10-CM.

The ICD-9 crosswalk has one major limitation. Code 826.0 covered all phalanx fractures of the foot, with no distinction of toe, laterality, displacement status, or encounter type. ICD-10-CM added the 7th character precision that lets payers separate S92.415K from S92.415D. ICD-9 carried no equivalent signal. Any practice analyzing nonunion episodes from ICD-9 historical data should apply that limitation when comparing claim patterns across the transition period.

How Pabau supports accurate ICD-10 coding for fracture encounters

Practices billing codes like ICD-10 Code S92.415K need documentation workflows that track encounter type across multiple visits. A patient may present with S92.415A at the initial visit and progress to S92.415K at a later encounter. The billing system has to flag that shift and prompt the correct 7th character. Pabau’s claims management tools carry the coding history of a fracture episode from the first visit to the last one.

• Encounter-type tracking: The Pabau client card keeps a visit-by-visit encounter log. Billing staff can check that the 7th character matches the visit type on record: initial, subsequent, or sequela.
• Diagnosis code search: The built-in ICD-10-CM lookup lets coders search by keyword, such as “nonunion,” “proximal phalanx,” or “great toe.” Reviewing the full descriptor before assignment cuts selection errors.
• Claim scrubbing via Claim.MD: Claims route through Claim.MD before submission, where code-level edits flag 7th character anomalies and CPT-diagnosis pairing issues. The integration supports 837P electronic claim submission and retrieval of 835 remittance advice for denial review.
• Laterality prompts: Digital intake and clinical documentation forms can capture laterality at the point of care. The left or right designation is then in the record before billing staff ever see the claim.

Reduce claim denials on fracture codes

Pabau’s built-in claims management tools track encounter types across visits and flag 7th character mismatches before submission. They connect directly to Claim.MD for electronic claim processing across 4,000+ US payers.

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Conclusion

ICD-10 Code S92.415K is a precise, fully billable code for the left great toe. It demands documentation specificity on six fronts: encounter type, laterality, digit, phalanx level, displacement status, and radiologically confirmed nonunion. The 7th character K is the most consequential element. Assigning it without imaging confirmation, or confusing it with G (delayed healing) or P (malunion), causes most denials on this code family.

Treat the imaging report as the gatekeeper for this code, and the rest of the descriptor takes care of itself. Pull the radiology read before the claim goes out. Those few minutes of checking trade for an appeal you never have to file. Book a demo to see how Pabau keeps encounter type, laterality and healing status aligned across a fracture episode.

Continue your research

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Managing a multi-visit fracture episode? Pabau’s superbill guide explains how to structure encounter-level billing documentation to support ICD-10 7th character accuracy across visits.

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