ICD-10 code S72.334N: nondisplaced oblique fracture of shaft of right femur with nonunion

Key takeaways

ICD-10 code S72.334N covers a nondisplaced oblique fracture of the shaft of the right femur. It applies at a subsequent encounter for an open type IIIA, IIIB, or IIIC fracture with nonunion.

S72.334N is a fully billable ICD-10-CM code for FY2026. The full seven characters are required on the claim, because S72.334 on its own is not billable.

The 7th character N marks confirmed nonunion at a Gustilo type IIIA, IIIB, or IIIC open fracture site. Documentation has to cover fracture morphology, open grade, and nonunion status.

The left-femur equivalent is S72.335N and the unspecified-femur equivalent is S72.336N. S72.331N through S72.333N are displaced oblique fractures, which is a different fracture pattern.

Practice management software like Pabau captures fracture morphology, Gustilo grade, and healing status at the point of care. That record is what supports a code like S72.334N on audit.

ICD-10 code S72.334N is a billable diagnosis code for a nondisplaced oblique fracture of the shaft of the right femur. It applies at a subsequent encounter, after an open fracture graded type IIIA, IIIB, or IIIC. Healing at that site has failed. This reference covers the code description, the 7th character logic, the Gustilo-Anderson classification, sibling codes, and documentation requirements.

Clinicians and coders working in orthopedic trauma, physical therapy, or sports medicine practice management use subsequent encounter codes constantly. The sections below break down every component of S72.334N, explain when it applies, and flag the common coding errors that lead to denials.

ICD-10 code S72.334N: description and billable status

ICD-10 code S72.334N is a fully billable, valid ICD-10-CM code for FY2026. It is classified as billable and specific, so it carries enough detail for claim submission and HIPAA-covered transactions.

Note that S72.334 without a 7th character is not billable. The Centers for Medicare and Medicaid Services (CMS) ICD-10-CM tabular list requires a 7th character extension for all S72 codes. Submitting a claim with the 6-character parent only results in automatic rejection.

Breaking down the ICD-10-CM code structure

Each character in S72.334N encodes a specific clinical dimension. Understanding the structure helps coders select the right code and gives clinicians a framework for what to document at each encounter.

The 6th character “4” is where displacement and laterality converge in the S72.33 subcategory. That single digit encodes both nondisplaced status and the right side. The left-femur equivalent is S72.335 and the unspecified-femur equivalent is S72.336.

The first three sixth characters, 1 through 3, belong to the displaced oblique codes S72.331, S72.332, and S72.333. Those describe a different fracture pattern entirely.

Understanding the 7th character ‘N’: nonunion in subsequent encounter

The 7th character is where most coding errors with S72.334N occur. Character N signals a subsequent encounter at an open fracture graded Gustilo-Anderson type IIIA, IIIB, or IIIC, where nonunion has been confirmed. Three conditions must all hold at once.

The visit must be a subsequent encounter rather than an initial one. The original fracture must have been an open type III, and nonunion must be documented.

The S72.3 shaft-of-femur codes use the full 16-character Gustilo extension set. Every character below is valid on S72.334, and each one names a different combination of encounter type, wound status, and healing outcome. Confusing N with K or M, the other two nonunion characters, is a denial trigger.

Delayed healing, which is character J at a type III open fracture site, is not the same as nonunion. Delayed healing is a radiographic slowing of callus formation without a definitive failed union.

Nonunion requires clinical or radiographic confirmation that bone healing has stopped. Assigning N without documented nonunion is a compliance risk flagged in AAPC coding guidance for musculoskeletal codes.

What is an open fracture type IIIA, IIIB, or IIIC?

The Gustilo-Anderson classification grades open fractures by wound size, periosteal stripping, and vascular involvement. Ramon Gustilo and John Anderson published the original three-type scheme in 1976.

The type III subdivision into IIIA, IIIB, and IIIC came later, in the 1984 paper by Gustilo, Mendoza, and Williams. Those three subtypes represent the most severe open injuries and carry the highest risk of infection, nonunion, and limb loss.

ICD-10-CM does not distinguish between IIIA, IIIB, and IIIC within the 7th character. All three map to character N for subsequent nonunion encounters. The Gustilo grade must be documented in the operative report or emergency record from the original injury.

A coder cannot assign a type III designation from a follow-up note alone. The original grading has to be traceable in the record.

When to use subsequent encounter codes for fractures

The ICD-10-CM Official Guidelines for Coding and Reporting cover this in Section I.C.19.a. A subsequent encounter applies once the patient has received active or definitive treatment for the injury. It then covers routine care during the healing phase, and care for complications. That includes follow-up visits, cast changes, physical therapy, and management of nonunion or malunion.

• Initial encounter (A, B, C): use while the patient is receiving active treatment for the fracture. That covers the emergency department, the operating room, the first orthopedic follow-up, and definitive fixation.
• Subsequent encounter (D through R): use for all follow-up visits after definitive treatment is underway, including PT and wound care visits related to the fracture.
• Sequela (S): use for late effects that appear after the acute phase has resolved, such as post-traumatic arthritis from a prior femur fracture.

The CDC/NCHS ICD-10-CM coding tool makes one point worth repeating. A subsequent encounter is any visit that happens after definitive treatment has begun, whatever its number in the sequence. A patient receiving outpatient wound care on day three after surgery is already at a subsequent encounter.

For physical therapy practices managing femur fracture rehabilitation, this distinction matters. PT visits for a patient mid-recovery from an open femur fracture with known nonunion should carry a subsequent encounter code, not an initial one. Using the wrong encounter character is among the most common denial triggers for musculoskeletal fracture claims.

S72.334N in the code hierarchy

S72.334N sits within a clearly defined code ancestry. Reading the hierarchy helps coders confirm they are at the right level of specificity. It also supports grouper logic in DRG assignment. Other parts of the femur sit under different subcategories of S72, such as S72.041B for the base of the femoral neck.

• S00-T88: Injury, poisoning, and certain other consequences of external causes
• S70-S79: Injuries to the hip and thigh
• S72: Fracture of femur
• S72.3: Fracture of shaft of femur
• S72.33: Oblique fracture of shaft of femur
• S72.334: Nondisplaced oblique fracture of shaft of right femur (requires 7th character)
• S72.334N: Subsequent encounter for open fracture type IIIA, IIIB, or IIIC with nonunion

The parent code S72.334 without a 7th character is listed in the tabular as requiring extension. Submitting S72.334 as a standalone code returns an invalid code error in clearinghouse edits. The CDC/NCHS ICD-10-CM files carry the tabular list where that requirement is set.

Related codes: siblings of S72.334N

S72.334N has two sets of neighbors. One set shares the base code S72.334 and varies only by 7th character. The other set shares the 7th character N and varies by side or by displacement.

The table below covers the codes most often confused with it in orthopedic follow-up. Codes for other regions of the femur, such as S72.452Q, follow the same seven-character logic.

Documentation requirements for S72.334N

Accurate assignment of ICD-10 code S72.334N depends on the medical record containing all of the following elements. A single missing component shifts the code to a less specific sibling or triggers a denial on audit.

• Fracture morphology: oblique fracture pattern must be documented (not comminuted, transverse, or spiral).
• Displacement status: nondisplaced must be explicitly stated. “Minimally displaced” does not qualify as nondisplaced under ICD-10-CM guidelines.
• Anatomical site: shaft of femur (diaphysis), not the neck, head, intertrochanteric region, or distal femur.
• Open fracture grade: Gustilo-Anderson type IIIA, IIIB, or IIIC must appear in the original injury record or operative report. A note that says open fracture without a grade defaults to type I or II.
• Encounter type: the visit must be a subsequent encounter, with active or definitive treatment already delivered.
• Confirmed nonunion: radiographic evidence, from X-ray or CT, or clinical confirmation of failed union must appear in the record. Delayed healing alone does not support character N.
• Laterality: the right femur must be identified in the record, since S72.334N is side-specific. The left femur is S72.335N.

Practices using digital clinical intake forms can build structured templates for this. The template prompts the provider to record fracture morphology, the original Gustilo grade, and current healing status at every visit. That turns documentation completeness into a workflow default, which is the strongest argument for structured medical forms in trauma follow-up.

Billing and coding considerations

S72.334N is used for nonunion management encounters. Those typically involve orthopedic surgeon follow-up, repeat imaging, and planning for surgery such as bone grafting, nail exchange, or revision of external fixation. The diagnosis code drives medical necessity for these services.

• Pair with CPT accurately: nonunion management often uses E/M codes such as 99212-99215 for established patients. Fracture care codes usually do not apply, because the original procedure’s global period has lapsed.
• Global period awareness: if the original fracture fixation is still within its global period, nonunion management may be separately reportable with modifier 58. Confirm the requirement with the payer.
• Imaging medical necessity: repeat radiographs or CT ordered to assess nonunion should carry the fracture nonunion diagnosis. Payers expect the diagnosis to explain the imaging request.
• Avoid upcoding to type III without documentation: character N needs a Gustilo type III designation in the original fracture record. The presentation at the follow-up visit does not substitute for it.
• External cause codes: some payers want the mechanism of the original injury reported alongside S72.334N. A motor vehicle accident, for example, adds a V-code on first submission under that payer.

Teams running claims management workflows should check one thing in the revenue cycle system. It has to carry the Gustilo grade forward from the original encounter. If that context is lost between visits, the coder defaults to type I or II.

Under-coding then becomes systematic, and the complexity of the case disappears from the record. The CMS ICD code lists carry the validated code sets accepted for Medicare and Medicaid billing.

S72.334N vs. adjacent codes: key differences

Three pairs of codes cause consistent confusion in clinical practice. Each distinction turns on a single clinical fact that must be traceable in the medical record.

S72.334N vs. S72.334J: nonunion vs. delayed healing

S72.334J is the subsequent encounter code for delayed healing at a type IIIA, IIIB, or IIIC open fracture site. Delayed healing means callus formation is slower than expected, but union has not been ruled out.

Nonunion means union has been clinically or radiographically confirmed as absent. The radiologist or treating surgeon has to state nonunion in the record. Phrases such as slow healing or limited callus support S72.334J instead. Using N when J applies inflates case complexity without support and attracts audit attention.

S72.334N vs. S72.334K: open grade matters

S72.334K is the subsequent nonunion code for a closed fracture. Both codes describe a nondisplaced oblique shaft fracture of the right femur with confirmed nonunion at a subsequent encounter. The differentiator is the original fracture’s open status.

If the original fracture was closed, with no skin breach, K is correct. If it was Gustilo type IIIA, IIIB, or IIIC, N is correct. A type I or II open fracture takes M instead. Practices using structured patient records with linked encounter history make that audit trail straightforward.

S72.334N vs. S72.335N and S72.336N: laterality specificity

S72.334N encodes the right femur. S72.335N encodes the left femur and S72.336N encodes an unspecified femur, with every other dimension identical. ICD-10-CM guidelines call for the most specific code the record supports. That makes S72.336N a last resort, used only when the chart genuinely does not identify a side.

A common error runs the other way. Coders reach for S72.331N or S72.332N because the numbers look adjacent, and those are displaced oblique fractures rather than nondisplaced ones.

How Pabau keeps fracture documentation attached to the claim

In most orthopedic practices the Gustilo grade is recorded once, in the operative report, and never surfaces again. Six months later a coder is reading a follow-up note that says nothing more specific than open femur fracture. The safe move is to code down to type I or II, and the complexity of the case disappears.

Practice management software like Pabau keeps that history in one patient file. Custom clinical forms can prompt the treating clinician to restate the fracture pattern, the original open grade, and the current healing status at every visit. Those fields stay on the chart, so the coder is not reconstructing an injury from a two-line progress note.

The outcome is a subsequent-encounter claim that carries its own evidence. When a payer asks why character N was assigned, the nonunion finding and the original Gustilo grade are already in the record. They sit in the order an auditor expects to read them.

Streamline clinical documentation at every encounter

Pabau keeps the fracture record and the claim in one system. Orthopedic and physical therapy teams capture the documentation details a code like S72.334N depends on.

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Conclusion

The four facts behind S72.334N all live in the record rather than in the coder’s judgment. If the Gustilo grade, the encounter type, the nonunion finding, or the side is missing, the correct code drops to a less specific sibling.

So the work belongs at the follow-up visit. Prompt the clinician for the grade and the healing status while the patient is still in the room. The coder then has everything the claim needs, and rework stops eating the billing week.

Pabau keeps the coded diagnosis attached to the visit record that becomes the claim. Book a demo to see how that works for orthopedic and trauma billing.

Continue your research

Coding the late effects of a femur fracture? S72.411S covers the sequela of a displaced condyle fracture of the right femur.

Working through knee injuries in the same rehab episode? S82.036S covers a nondisplaced transverse patella fracture at the sequela stage.

Documenting soft tissue damage alongside the fracture? S76.129S covers a quadriceps laceration once the acute phase has resolved.

Writing progress notes across a long rehab course? Therapy progress notes gives you a repeatable structure for documenting each visit.

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