ICD-10 Code S92.301K: Metatarsal fracture with nonunion

Key Takeaways

ICD-10 Code S92.301K describes a fracture of unspecified metatarsal bone(s) of the right foot, subsequent encounter for fracture with nonunion.

S92.301K is a valid, billable ICD-10-CM code effective October 1, 2025 (FY2026) and can be used in all HIPAA-covered transactions.

The 7th character K signals nonunion (fracture not healing), which differs from G (delayed healing) – misassigning these characters is a common claim denial trigger.

Practice management software like Pabau supports structured clinical documentation that captures laterality, encounter type, and healing status, so coders can justify S92.301K before a claim goes to billing.

ICD-10 Code S92.301K identifies a fracture of unspecified metatarsal bone(s) of the right foot at a subsequent encounter where the bone has failed to unite. It’s the code coders reach for once imaging confirms nonunion rather than routine or delayed healing.

This page covers the full 7th-character set for S92.3 fractures, the coding hierarchy, related sibling codes, and the documentation payers expect before approving a nonunion claim.

ICD-10 Code S92.301K: definition and clinical description

ICD-10 Code S92.301K is the billable diagnosis code for a fracture of unspecified metatarsal bone(s) of the right foot at a subsequent encounter where the fracture has resulted in nonunion. The 7th character K signals to payers that healing has failed, which triggers different coverage rules than routine follow-up.

This reference covers billability, the full 7th character extension table, the clinical distinction between nonunion (K) and delayed healing (G), documentation requirements, the S92 code hierarchy, and related codes. It also covers billing and reimbursement considerations that most code-lookup pages skip.

Understanding the 7th character ‘K’ in fracture codes

The 7th character is the difference between a clean claim and a denial. For S92.301K, the K specifically communicates that the patient is at a subsequent encounter and the fracture has developed nonunion. The CMS ICD-10-CM coding guidelines define the full extension set for fracture codes, and the S92.301 family uses 7 valid 7th characters.

Unlike long-bone fracture families such as S82 (tibia/fibula), the S92 metatarsal set does not split its subsequent-encounter characters by open versus closed fracture or by Gustilo type. K covers nonunion regardless of whether the original fracture was open or closed.

S92.301K vs S92.301G: nonunion vs delayed healing

The distinction between K and G is one of the most commonly misapplied coding choices in physical therapy and podiatry billing. Both are subsequent encounter codes, but they describe different healing states.

Clinicians documenting a metatarsal fracture nonunion should ensure the note explicitly states that healing has failed, not merely stalled. The distinction between G and K on the claim changes coverage and pre-authorization requirements.

When to use S92.301K: subsequent encounter guidelines

The ICD-10-CM Official Guidelines for Coding and Reporting define a subsequent encounter as any visit after the patient has received active treatment and the fracture is in the healing phase. Using the K character requires two conditions: the encounter is subsequent (not the initial treatment visit) and the fracture has not united.

Documentation requirements for S92.301K

Missing any of these documentation elements is the fastest route to a claim denial. The clinical note must establish all of the following to support ICD-10 Code S92.301K.

• Laterality: The note must specify the right foot. “Bilateral” or “foot, unspecified” do not support S92.301K.
• Anatomical site: The metatarsal bone is identified, even if the specific metatarsal number is not documented (unspecified metatarsal is acceptable for this code family, but the site must be named).
• Encounter type: The note must reflect a subsequent visit. An initial treatment encounter uses A or B, not K.
• Nonunion status: The note must document that the fracture has failed to heal. Acceptable language includes “fracture nonunion confirmed on imaging,” “no callus formation at [date],” or “failed conservative management with persistent fracture line.”
• Imaging reference: While not strictly mandated by ICD-10-CM guidelines, a reference to supporting radiology (X-ray or CT) significantly reduces the risk of medical necessity denials for nonunion-related treatment.

Practices using claims management software that integrates with clinical documentation can flag incomplete documentation before submission, reducing the turnaround time on nonunion claims. Practice management software like Pabau supports structured clinical note workflows that help coders verify laterality, encounter type, and healing status are documented before the practice submits the claim.

Reduce claim denials with structured documentation workflows

Pabau helps podiatry and orthopedic practices document nonunion fracture encounters accurately – capturing laterality, imaging references, and encounter type before the claim goes out.

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S92.301K in the ICD-10-CM code hierarchy

S92.301K sits at the end of a five-level code hierarchy. Understanding the parent-child structure helps coders navigate laterality and specificity decisions quickly. According to the CDC ICD-10-CM web tool, the hierarchy for this code is as follows.

S92.301 on its own is not billable, and submitting a claim with the parent code but no 7th character results in rejection. The full S92.301 family contains 7 valid 7th characters (A, B, D, G, K, P, S), each a distinct encounter type and healing status combination.

Practices coding musculoskeletal fracture cases should always use the most specific 7th character available.

Related ICD-10 codes for metatarsal fractures

The S92.301 code family branches by laterality and by 7th character. Coders working with sports medicine patients billing metatarsal fractures encounter these sibling and laterality codes frequently, alongside related lower-extremity nonunion diagnoses like S82.232M and S82.155P. The table below covers the most clinically relevant related codes.

Approximate synonyms for S92.301K

The following alternative clinical descriptions map to ICD-10 Code S92.301K and may appear in physician documentation. Coders encountering any of these phrases should code to S92.301K when the encounter type and laterality match.

• Nonunion of fracture of right metatarsal
• Fracture of metatarsal bone of right foot, nonunion, subsequent encounter
• Right metatarsal fracture with failed healing, follow-up visit
• Closed fracture of right metatarsal, nonunion, subsequent care
• Fracture of unspecified right foot metatarsal, subsequent encounter, nonunion

Billing and reimbursement considerations for metatarsal fracture nonunion

Nonunion fracture codes attract closer payer scrutiny than routine fracture follow-up codes. Practices billing S92.301K should anticipate the considerations below before submission. The AAPC ICD-10-CM code lookup is useful for verifying billability and code edits before claim submission.

HIPAA compliance and transaction validity

S92.301K is confirmed as valid for use in all HIPAA-covered transactions. Any HIPAA-covered entity submitting this code on an 837P or 837I claim is compliant with HIPAA transaction standards. Practices unsure about their HIPAA compliance obligations for medical offices should review their transaction code sets against the current FY2026 ICD-10-CM edition.

Common denial patterns for nonunion codes

Several specific denial patterns appear when S92.301K is submitted without adequate supporting documentation.

• Missing laterality in documentation: The claim uses S92.301K (right foot), but the clinical note does not specify the foot. Payers may deny or return the claim for clarification.
• Wrong encounter type: Using K at an initial encounter visit. K requires a subsequent encounter – if the patient is being seen for the first time for this fracture, use A or B.
• G vs K confusion: Submitting K when the documentation supports only delayed healing. Payers may request imaging to distinguish delayed healing from nonunion.
• Parent code submitted: Billing S92.301 instead of S92.301K. The parent code is not billable and is rejected at the clearinghouse level.
• Missing imaging documentation: Nonunion claims for surgical intervention (e.g. bone grafting, intramedullary fixation) typically require radiology reports confirming the nonunion. Claims lacking this documentation frequently receive additional development requests.

MS-DRG and MDC classification for S92.301K

For inpatient claims, S92.301D, S92.301G, S92.301K, and S92.301P all fall under MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue). Under the FY2026 ICD-10-CM/PCS MS-DRG grouper (version 43.0), S92.301K groups into the 564-566 “Other Musculoskeletal System and Connective Tissue Diagnoses” DRG family, split by whether a CC or MCC is also present on the claim.

Because this is a diagnosis code rather than a procedure, the DRG actually assigned depends on the principal diagnosis and any other reported conditions. Always confirm against the current grouper logic rather than assuming a single fixed DRG.

Practices managing high volumes of fracture follow-up cases may benefit from structured digital intake and clinical documentation forms that prompt clinicians to document laterality, encounter type, and healing status on every visit. Consistent documentation upstream prevents the downstream denial cycle. For podiatry practices specifically, standardized note templates for medical forms and clinical documentation at every encounter stage reduce coding ambiguity.

Approximate synonyms and coding tips for S92.301K

Coders searching the ICD-10-CM index under terms like “fracture, metatarsal, right, nonunion” or “nonunion, fracture, foot” should be directed to the S92.301 code family. Always cross-reference the alphabetical index entry with the tabular list to confirm the correct 7th character before finalizing the code.

A few practical tips specific to this code family:

• If the specific metatarsal bone number is documented (e.g. 5th metatarsal Jones fracture), consider codes within S92.35 (fracture of fifth metatarsal) rather than S92.301K, which is used when the specific metatarsal is not identified.
• The S92 metatarsal family does not distinguish open from closed fractures at the subsequent-encounter stage. Nonunion is coded K regardless of whether the original fracture was open or closed.
• The code became effective October 1, 2025 for FY2026 and has been valid since the S92 family was introduced in ICD-10-CM. No recent structural changes affect its use.
• Medicare Part B covers nonunion management under its outpatient orthopedic and podiatric services. Documentation requirements follow the same CMS clinical documentation standards that apply across ICD-10-CM diagnosis coding.

ICD-9-CM crosswalk (approximate)

For historical claims research or legacy systems, the CMS General Equivalence Mappings (GEMs) don’t provide a single ICD-9-CM code that captures site, laterality, and nonunion status the way S92.301K does. Going backward from ICD-10-CM to ICD-9-CM, the closest approximate equivalents are 825.25 (closed fracture of metatarsal bone(s)) for the underlying fracture and 733.82 (nonunion of fracture) to flag the nonunion status.

Both are approximate mappings only. ICD-9-CM was retired for U.S. claims on October 1, 2015, and neither legacy code distinguishes right foot from left the way ICD-10-CM does.

For practices handling the full spectrum of foot fracture billing, accurate ICD-10 coding starts with complete clinical documentation captured at the point of care, kept consistent between the note and the claim.

Conclusion

Metatarsal nonunion claims are among the most denial-prone fracture codes in outpatient orthopedic and podiatry billing. The core risk is documentation: a note that doesn’t clearly establish laterality, encounter type, and failed healing status leaves the coder guessing and the payer skeptical.

Pabau gives podiatry and orthopedic practices a structured workflow to capture the documentation that ICD-10 Code S92.301K requires, so the note supports the claim the practice submits. To see how it handles fracture follow-up documentation in practice, book a demo with the team.

Continue your research

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Preparing a paper claim for a payer that doesn’t accept electronic submission? Pabau’s CMS-1500 form template covers the fields required for fracture follow-up claims.

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