ICD-10 Code S72.431C: Displaced fracture of medial condyle, right femur

Key takeaways

ICD-10 Code S72.431C describes a displaced fracture of the medial condyle of the right femur. It applies to the initial encounter for an open fracture.

S72.431C is billable under the 2026 ICD-10-CM edition. Its parent code S72.431 is non-billable and cannot go on a claim.

The 7th character C covers Gustilo-Anderson types IIIA, IIIB, and IIIC. Choosing the wrong 7th character is the most common error in this family.

Practice management software like Pabau captures laterality, displacement, and encounter type as structured fields, so coders can select the 7th character without a chart query.

ICD-10 Code S72.431C is a billable ICD-10-CM code for a displaced fracture of the medial condyle of the right femur. It applies at the initial encounter, when the fracture is open and graded Gustilo type IIIA, IIIB, or IIIC. This reference covers the code hierarchy, the 7th character system, and the Gustilo criteria. It also sets out the documentation each element needs and the errors that get these claims denied.

According to the Centers for Medicare and Medicaid Services (CMS), ICD-10-CM codes are updated annually each October 1. The 2026 edition, effective October 1, 2025, carries S72.431C as a current, billable diagnosis code. Coders in orthopedic, urgent care, and trauma settings meet it on high-severity open femur fractures that need surgical management.

ICD-10 Code S72.431C: definition, billable status, and effective date

ICD-10 Code S72.431C is a specific, billable ICD-10-CM diagnosis code valid for reimbursement. It describes a displaced fracture of the medial condyle of the right femur. The fracture is open at first presentation and graded Gustilo type IIIA, IIIB, or IIIC. The subsequent-encounter counterpart for the same injury with malunion is S72.431R.

Understanding the 7th character extensions for S72.431

The parent code S72.431 is non-billable. To submit a claim, coders select one of the billable child codes by appending the correct 7th character. That character sets the encounter type and, for open fractures, the Gustilo grade. The same encounter-type logic drives every other femur subcategory, including S72.451K.

Key rule: ICD-10 Code S72.431C is used only for the initial encounter. Once the patient returns for follow-up care on the same fracture, the coder switches to the matching subsequent-encounter code. For Gustilo type III injuries that means F, J, N, or R, depending on how the fracture is healing.

Gustilo open fracture classification: types IIIA, IIIB, and IIIC

The Gustilo-Anderson classification is the accepted standard for grading open fracture severity in orthopedic and trauma settings. The 7th character system that carries that grade into a diagnosis code is specific to ICD-10-CM. It is governed by the official ICD-10-CM guidelines maintained by CMS and the CDC’s NCHS. The 7th character C in ICD-10 Code S72.431C maps to all three type III subgroups. ICD-10-CM groups IIIA, IIIB, and IIIC under a single character rather than giving each subtype its own code.

The operative note and emergency department record must state the Gustilo classification outright, or describe the wound well enough for the coder to determine it. Coders do not assign type III on their own. The treating physician or surgeon makes that call.

Anatomy: medial condyle fracture coding and laterality

The medial condyle is the inner projection at the distal end of the femur, forming part of the knee joint. Fractures here are distinct from neck-of-femur fractures, commonly called hip fractures, and from mid-shaft femur fractures. Laterality is a required element across all S72 subcategories, exactly as it is for forearm codes such as S52.262K.

• Medial condyle location: distal femur, medial aspect, adjacent to the medial collateral ligament
• Clinical significance: intra-articular fracture risk, with post-traumatic arthritis a concern if displacement is inadequately reduced
• Laterality in ICD-10-CM: S72.431x for the right femur, S72.432x for the left, S72.433x when the side is not documented
• Why right vs. left matters: payer systems validate laterality against operative reports, and a mismatch triggers a denial

Displaced vs. non-displaced fractures: how the distinction affects code selection

Displacement status is built into the code itself, not added as a modifier or qualifier. S72.431C codes a displaced fracture. A non-displaced fracture of the medial condyle of the right femur maps to the S72.434x family instead. Using S72.431C for a non-displaced fracture misrepresents clinical severity and can affect both reimbursement and quality reporting.

There is no “unspecified displacement” option in this subcategory. The official ICD-10-CM guidelines direct coders to treat a fracture as displaced when the record does not say which it is. Query the treating provider anyway when the operative or radiology report is ambiguous, because the default is a fallback rather than a finding.

S72.431C sibling, parent, and related codes

Understanding the hierarchy prevents the most common error in this family: submitting the non-billable parent S72.431 on a claim. Use the AAPC ICD-10-CM code lookup to confirm hierarchy and billable status across the full S72 family. Pabau’s claims management software maps each diagnosis code to its claim field, so a parent code is less likely to slip through.

• S72.431 (non-billable parent): displaced fracture of medial condyle of right femur, which needs a 7th character before it can be submitted
• S72.431A: initial encounter, closed fracture
• S72.431B: initial encounter, open fracture type I or II
• S72.431C: initial encounter, open fracture type IIIA, IIIB, or IIIC
• S72.432x family: displaced fracture of medial condyle of left femur, the mirror codes
• S72.434x family: non-displaced fracture of medial condyle of right femur
• S72.42x family: fracture of lateral condyle of femur
• S72.0xx family: fracture of head and neck of femur, the true hip fractures

Documentation requirements for accurate open fracture coding

Every element of ICD-10 Code S72.431C must appear in the clinical record before the code is assigned. Miss one element, such as Gustilo type or laterality, and the coder falls back to a less specific code. That costs reimbursement accuracy and audit performance. Purpose-built clinical documentation software and structured digital clinical forms capture all of these fields at the point of care.

• Fracture location: medial condyle of femur, not just “distal femur” or “knee fracture”
• Laterality: right femur stated explicitly in the operative or ED note
• Displacement status: displaced fracture confirmed on imaging or intraoperative assessment
• Open vs. closed: wound description confirming bone exposure or communication with the fracture site
• Gustilo classification: type IIIA, IIIB, or IIIC stated by the treating surgeon
• Encounter type: initial encounter confirmed, meaning the first active treatment for this injury
• Mechanism of injury: recommended so the fracture code can be paired with an external cause code

Orthopedic practices using structured patient records can make fracture classification a mandatory field. The detail lands in the chart as the note is written, not during a retrospective coding query.

Billing and reimbursement considerations for ICD-10 Code S72.431C

Gustilo type III open femur fractures are high-acuity injuries, usually managed in inpatient or surgical settings. Claims carrying ICD-10 Code S72.431C pair with CPT codes for open reduction and internal fixation or external fixation, depending on the operative approach. Confirm the payer’s medical necessity crosswalk requirements before submission. HIPAA-compliant coding workflows keep the transmitted diagnosis data within federal requirements for protected health information.

• Present on admission (POA): verify POA status for S72.431C against the current CMS indicator list, which applies to facilities billing under the IPPS
• Payer preauthorization: type III fractures often need surgical authorization, so confirm it with the payer before the procedure
• External cause codes: append the mechanism-of-injury code, such as W19.XXXA for an unspecified fall, alongside the fracture diagnosis
• Inpatient vs. outpatient: S72.431C is valid in both settings, and inpatient DRG assignment turns on the principal diagnosis and procedure codes

Common coding errors and how to avoid them

The S72.431 family generates predictable findings in orthopedic billing audits. Practices that connect the clinical note directly to their medical billing process catch most of these before the claim leaves the building.

• Submitting the non-billable parent S72.431: the most frequent error. S72.431 without a 7th character is rejected by all payers. Always use a fully specified child code.
• Selecting 7th character A instead of C: A denotes a closed fracture at initial encounter. Using it for an open fracture misrepresents the clinical findings. Confirm open vs. closed in the operative or ED record first.
• Selecting 7th character B instead of C: B maps to Gustilo type I or II. If the documentation states type IIIA, IIIB, or IIIC, the character must be C. Downcoding to B can reduce reimbursement and shift DRG assignment.
• Missing laterality: coding S72.433 for an unspecified side when the record clearly documents a right-side injury. Specificity wins whenever the documentation supports it.
• Using initial encounter codes for follow-up visits: the encounter type shifts to D, E, or F once active treatment ends. Keeping S72.431C on later visits is incorrect.
• Failing to pair with external cause codes: ICD-10-CM guidelines direct coders to report external cause codes as secondary diagnoses, particularly on inpatient claims.

How practice management software supports fracture code accuracy

Open fracture codes carry high denial rates because the required documentation elements are numerous and time-sensitive. Today most orthopedic teams collect them in free-text notes, then chase the surgeon weeks later when the coder cannot find a Gustilo grade. Practices running a physical therapy EMR or sports medicine software with structured templates avoid that loop.

Pabau does the same job for orthopedic and musculoskeletal practices. Laterality, displacement status, and fracture classification become discrete fields on the clinical note rather than sentences someone has to interpret. Every subscription includes those documentation tools, so no part of the workflow sits behind a higher tier.

The outcome is a shorter path from surgery to a clean claim. The billing team can assign ICD-10 Code S72.431C the same week the patient is treated, without a provider query or a chart audit first.

Reduce coding errors before claims go out

Pabau captures fracture laterality, displacement status, and Gustilo classification as structured fields. Your billing team gets everything it needs to pick the right ICD-10 code at submission.

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Conclusion

S72.431C is only as defensible as the four elements behind it. Those are displacement, medial condyle location, right-side laterality, and a surgeon-documented Gustilo type III at initial encounter. Chase those four at the point of care, not at the point of denial.

The trade-off worth remembering is that specificity cuts both ways. A record that supports C earns the acuity it describes, while a thin record pushes you to a vaguer code and a smaller payment. To see how Pabau supports accurate ICD-10 documentation workflows, book a demo.

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