ICD code S02.11DK – Type II occipital condyle fracture, left, nonunion

Key takeaways

ICD-10 Code S02.11DK codes a left-side Type II occipital condyle fracture at a follow-up visit where nonunion is confirmed.

The 7th character K means the fracture is still in active treatment but has failed to heal, as shown on imaging in the record.

Coders most often go wrong by using 7th character A at follow-up visits, or S before fracture care has ended.

The 6th character carries both the fracture type and the side, so a Type III left-side nonunion is S02.11FK, not S02.11BK.

Pabau’s claims management software submits claims through the Claim.MD clearinghouse, with eligibility checks, remittance tracking and completeness checks before submission.

ICD-10 Code S02.11DK: Code details at a glance

ICD-10 Code S02.11DK is the billable code for a left-side Type II occipital condyle fracture that has failed to unite. Report it at follow-up visits once imaging confirms nonunion and fracture care is still ongoing.

The table below summarizes the reference data. Every field reflects the CMS ICD-10-CM Fiscal Year 2027 release, effective October 1, 2026 through September 30, 2027.

Breaking down each character in S02.11DK

Each position in this seven-character code carries a distinct clinical meaning. Misread any one position and the claim codes a different anatomical site, fracture type, or encounter stage. The table below maps every character to its meaning.

Position 6 (D) encodes the fracture type and the side together. A and B are Type I (right and left), C and D are Type II, and E and F are Type III. Switching D to F codes a Type III fracture on the same left side. That is a clinically different injury with different stability implications.

The decoder below shows both letters, and what each one turns into when the documented facts change.

Clinical description: Type II occipital condyle fracture

A Type II occipital condyle fracture is a basilar skull fracture that extends into the occipital condyle, caused by a direct blow to the skull. It typically follows high-energy trauma such as motor vehicle collisions or falls from height. The Anderson-Montesano classification divides occipital condyle fractures into three types, and ICD-10-CM’s S02.11 codes follow it.

Left-side laterality matters for coding because ICD-10-CM assigns separate codes for left and right occipital condyle fractures. The clinical note must explicitly state which side is affected. Inferring laterality from imaging reports without physician documentation is a coding violation under CMS guidelines.

Understanding the 7th character K: Subsequent encounter for fracture with nonunion

The 7th character K means the fracture remains in active treatment but has failed to heal. The bone ends have not bridged, which is typically confirmed by CT or MRI. Per the CDC/NCHS ICD-10-CM Official Guidelines, Section I.C.19.a, K applies while the patient is still receiving care for the fracture. Imaging or clinical assessment must document the nonunion.

The clinical decision point between K and G is imaging. G applies when the fracture is slow to heal but still consolidating. K applies when consolidation has stopped and the fracture gap persists. Document which character applies based on the radiology report, not solely on elapsed time since injury.

When to use S02.11DK: Applicable clinical scenarios

S02.11DK applies only when all four conditions are met simultaneously. Missing any one pushes the correct code to a different 7th-character variant or a different subcategory entirely.

• Encounter type is subsequent: the patient has already received initial treatment for this fracture at a prior encounter. A first ED presentation codes A (or B for an open fracture), not K.
• Fracture site is the left occipital condyle: the clinical documentation explicitly states left side. Right-side fractures code to a different code string (S02.11CK for Type II right-side nonunion).
• Fracture type is Anderson-Montesano Type II: the physician’s note or radiology report must state Type II, or describe a skull base fracture reaching the condyle. Coders cannot assign the type from mechanism alone.
• Nonunion is confirmed: imaging (CT or MRI) documents absence of bony bridging. The imaging report or the clinical note must confirm this finding.

A common scenario: a patient initially coded S02.11DA (initial encounter, Type II left-side fracture) returns at eight weeks with a CT showing no callus formation. That follow-up visit codes S02.11DK, not a repeat of S02.11DA.

Codes commonly confused with S02.11DK

The following codes share the same anatomical site or encounter structure but differ in one or more critical dimensions. Billing one of them when S02.11DK is correct, or the reverse, creates a mismatch that payers flag on audit.

S02.11DK vs S02.11DS: Nonunion versus sequela

Mixing up K and S is a frequent error on late-stage occipital condyle fracture claims. Both apply after the initial encounter, but they code different clinical states.

• K (S02.11DK): the fracture is still being actively treated. The patient is returning for care directed at the fracture itself, such as monitoring, surgical planning, or surgery for nonunion. The fracture has not healed, and the clinician is still managing it.
• S (S02.11DS): fracture care has ended. The patient presents with a late effect of the original fracture, such as chronic neck pain, a cranial nerve deficit, or cervical instability. Code the sequela condition as the principal diagnosis and S02.11DS as the underlying cause.

Here’s a practical test. If the visit note describes ongoing fracture management or nonunion intervention, K applies to the visit. If the note describes a new symptom from a healed fracture, switch to S and code that condition first. The same split applies on the right side, where the Type II sequela code is S02.11CS.

Documentation requirements for S02.11DK

The medical record must support every element embedded in the code. Nonunion extends reimbursable treatment and can trigger surgical authorization, so payers look closely at these follow-up claims. Knowing what makes a clean claim starts with complete documentation. A complete note for S02.11DK should include the following.

• Explicit fracture type: the note must state “Type II” or “Anderson-Montesano Type II”, or the radiology report linked in the record must do so. Do not expect coders to classify the fracture from mechanism description alone.
• Left-side laterality: a specific statement that the affected condyle is on the left side. “Bilateral” or “left and right” are not acceptable for a laterality-specific code.
• Encounter designation as subsequent: the note should confirm this is a follow-up for a previously diagnosed and treated fracture, not a new presentation.
• Imaging evidence of nonunion: a CT or MRI report, dated on or before the encounter, showing absent bony bridging or failed consolidation. “Nonunion” should appear in the imaging interpretation or the clinician’s assessment.
• Active treatment context: a statement that fracture management is ongoing, rather than finished with the patient now presenting a late symptom.

Payer requirements and claim submission for S02.11DK

Medicare and most commercial payers process occipital condyle fracture claims under general traumatic injury coverage. There is no national coverage determination (NCD) specific to skull base fractures, so local coverage determinations (LCDs) govern. Practices should verify applicable LCDs through their Medicare Administrative Contractor before submitting claims for surgical interventions associated with S02.11DK.

• Prior authorization for surgery: surgical procedures linked to nonunion, such as occipitocervical fusion, typically require prior authorization from Medicare Advantage plans and most commercial payers. The authorization request should reference S02.11DK and include the imaging report confirming nonunion.
• Imaging documentation on file: many payers require the imaging report to be available for retrospective audit even when it is not submitted with the claim. Keep the CT or MRI report in the patient record and note the study date in the encounter documentation.
• Medicare secondary payer coordination: some trauma patients have Medicare plus a liability or workers’ compensation payer. Verify coordination of benefits before submission to avoid a rejection on the primary side.

Common claim denial reasons for S02.11DK

The seven-character string leaves no room for a vague note, because each element has to be backed by the record. Solid denial management workflows help practices recover faster, but preventing denials at submission costs less. These are five common denial triggers for S02.11DK.

Payers return these denials with adjustment reason codes, and our guide to decoding denial codes explains what each one means.

ICD-10-CM code hierarchy: where S02.11DK sits

ICD-10-CM codes are only valid for claim submission at the most specific level, which here is the full seven-character string. Billing a parent code (S02.11, S02.1, or S02) returns a claim as invalid because those codes are header-level only.

The hierarchy below shows every level from chapter to code, with validity notes at each level. Coders navigating from the AAPC Codify ICD-10-CM lookup or the WHO ICD-10 browser should always stop at the seven-character level before billing.

• Chapter 19 (S00-T88): Injury, poisoning and certain other consequences of external causes (header only, not billable)
• Block S00-S09: Injuries to the head (header only, not billable)
• S02: Fracture of skull and facial bones (header only, not billable)
• S02.1: Fracture of base of skull (header only, not billable)
• S02.11: Fracture of occiput (header only, not billable)
• S02.11D: Type II occipital condyle fracture, left side (header only, requires a 7th character)
• S02.11DK: Type II occipital condyle fracture, left side, subsequent encounter for fracture with nonunion (billable, submit this code)

Annual validity: Is S02.11DK valid for FY 2027?

S02.11DK is valid and billable for Fiscal Year 2027, which runs from October 1, 2026 through September 30, 2027. The FY 2027 CMS ICD-10-CM release leaves it unrevised. The code has stayed stable across recent annual updates, with no descriptor changes or deletions.

Check it against the CMS tabular list at each October 1 update, because the annual release is the authoritative source. Claims with dates of service after September 30, 2027 fall under the FY 2028 code set.

How claims management software reduces denials on S02.11DK

A follow-up claim for S02.11DK often carries a prior authorization number and relies on a CT report on file. The payer may also need coordination of benefits. When those details live in a clearinghouse portal and a spreadsheet, claims go out incomplete and denials surface late.

Pabau’s claims management software submits claims electronically through the Claim.MD clearinghouse. It checks patient eligibility before the visit and tracks electronic remittance advice (ERA) once the payer responds. Before a claim goes out, it also checks that administrative fields such as membership numbers and authorization codes are complete.

Fewer claims bounce back for missing details, and a denied S02.11DK claim shows up quickly enough to correct and resubmit. The diagnosis code itself still comes from your coder and the clinical note.

Fewer denials on complex fracture claims

Pabau sends claims through Claim.MD with eligibility checks, completeness checks on authorization and membership fields, and remittance tracking. Fewer claims bounce back, and payments arrive faster.

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Conclusion

The imaging report decides S02.11DK. If the latest CT or MRI documents nonunion and the fracture is still being managed, K is the right 7th character. If healing is slow but progressing, G fits better. Once fracture care ends, the code moves to S.

Most denials on this code are fixed before billing starts. Get the fracture type, the left side, and the nonunion finding into the note, and the 6th and 7th characters follow from the record. If your team is newer to the claim cycle, start with medical billing fundamentals.

Book a demo to see how Pabau’s claim submission, eligibility checks and remittance tracking keep fracture follow-up claims moving.

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