ICD-10 Code S72.451K: Displaced supracondylar fracture nonunion

Key takeaways

S72.451K is a billable ICD-10-CM code for a displaced supracondylar fracture of the lower right femur. It applies at subsequent encounters when nonunion is documented.

The 7th character K marks a follow-up encounter for a closed fracture that has failed to heal. It separates this code from D for routine healing and S for sequela.

Without intracondylar extension means the fracture line does not cross the joint surface into the condyles. That places the code in the S72.451 family rather than the condylar families.

Pabau, an all-in-one practice management system, submits orthopedic claims electronically, runs real-time eligibility checks, and tracks each claim through to payer resolution.

ICD-10 Code S72.451K: Quick reference

ICD-10 Code S72.451K is a billable code for a displaced supracondylar fracture of the right distal femur. It applies at a follow-up encounter where the closed fracture has been documented as a nonunion. The 7th character K is what carries the nonunion status, and it separates this code from S72.451D and S72.451P.

This reference covers the full code description, the complete 7th-character set, adjacent codes, and documentation requirements. It closes with the coding errors that most often send these claims back.

Full code description and clinical meaning of ICD-10 Code S72.451K

Every word in the full description of ICD-10 Code S72.451K carries coding weight. Misread any element and you land on a different code. Here is what each component means:

• Displaced: The fracture fragments have moved out of their normal anatomical alignment. Contrast with nondisplaced (S72.461K), where the bone cracks but stays in position.
• Supracondylar: The fracture occurs in the distal femur, above the femoral condyles. It does not involve the condylar articular surfaces themselves.
• Without intracondylar extension: The fracture line does not extend into the condyles or the knee joint surface. This is the critical qualifier separating S72.451K from intercondylar and condylar fracture codes. See the anatomy section below for the clinical significance.
• Lower end of right femur: Specifies the anatomical region (distal femur) and laterality (right). The left counterpart is S72.452K.
• Subsequent encounter: This is not the patient’s first visit for this injury. The acute phase is over and the patient is in active follow-up or ongoing management.
• Closed fracture: The skin is intact over the fracture site. No open wound communicating with the fracture.
• Nonunion: The bone has failed to heal within the expected timeframe. The 7th character K encodes this specific complication.

A coder working from an operative or clinic note needs all seven of these descriptors documented to support S72.451K. If any one of them is missing, especially laterality or the nonunion status, payers will question the code. Practice management software like Pabau submits the finished claim electronically and reports its status back. An incomplete record surfaces as a payer response you can act on.

Anatomy: what is a supracondylar fracture of the femur without intracondylar extension?

The distinction between supracondylar and intracondylar is one that coders and clinicians regularly conflate. Understanding the anatomy makes the coding decision straightforward.

The distal femur widens as it approaches the knee and splits into two rounded projections: the medial and lateral condyles. The region just above this split, where the femoral shaft transitions into the condylar flare, is the supracondylar zone. A fracture here stays proximal to the joint surface.

Supracondylar fractures without intracondylar extension are common in high-energy trauma and in older patients with osteoporosis. Orthopedic teams use physical therapy practice software to coordinate rehabilitation tracking across post-operative visits. The qualifier matters for surgical planning too, since intraarticular extension changes the operative approach. A medial condyle fracture coded as S72.431C sits in a separate family for that reason.

Understanding the 7th character K: subsequent encounter for nonunion

The 7th character in ICD-10-CM fracture codes does the heaviest lifting. For any S72.451x code, the 7th character tells the payer exactly where the patient is in their fracture care journey. Getting this wrong is the most common reason these claims are denied.

Fracture codes are more complex than most ICD-10-CM categories because S72.451 takes 16 different 7th characters. Six of them cover closed fractures and sequela. The other ten cover open fractures, split by Gustilo type. Open-fracture nonunion is coded with M or N rather than K, in the same way S72.431R handles an open malunion. The full table is in the next section.

• K applies when: The patient is seen after the acute fracture event, at a subsequent encounter. Imaging or clinical assessment documents that the fracture has not united within the expected period.
• K does not apply when: The fracture is healing routinely (D) or slowly (G). It also does not apply while the acute injury is still being assessed (A, B, or C). For an open fracture with nonunion, use M or N.
• K vs D in practice: Many practices switch from D to K too late. The encounter code changes to K the moment the physician documents “nonunion” or “failed healing” in the note. Elapsed time does not matter.

ICD-10-CM Official Guidelines set no fixed timeline for nonunion. The determination rests with the treating physician, supported by imaging. Document it explicitly and the K character is supported. Without that documentation, payers will question the code.

All 7th character variants for S72.451: complete code table

S72.451 is the 6-character parent covering displaced supracondylar fractures without intracondylar extension of the lower end of the right femur. The 7th character determines the complete, billable code. All 16 valid characters are listed below, including the open-fracture characters that many coding references leave out.

According to the CMS ICD-10-CM coding guidelines, the 7th character reflects the status of the fracture at the time of the encounter. The overall stage of care does not decide it. A new injury seen in the emergency department always takes the A character. That holds even at the hospital that treated the patient’s previous fracture.

What is fracture nonunion? Clinical and coding implications

Nonunion means the fracture has not healed and is unlikely to heal without intervention. It is a clinical diagnosis, confirmed by imaging, and it changes both the treatment plan and the coding approach.

Radiographically, nonunion typically shows persistence of the fracture gap, sclerosis of the fracture ends, or the formation of a pseudarthrosis (a false joint). Clinically, the patient often reports ongoing pain at the fracture site and, in weight-bearing bones like the femur, difficulty with ambulation.

• Documentation trigger: The physician must explicitly document “nonunion” or equivalent language (“failed fracture healing,” “absent bridging callus on imaging”) in the clinical note. Coders cannot infer K from elapsed time alone.
• Coding implication: Once nonunion is documented, K replaces D on every subsequent encounter for this injury. That holds until the fracture unites or the patient is treated for sequela.
• Treatment context: Nonunion management frequently involves bone grafting, revision fixation, or bone stimulation. Each procedure has its own CPT code and should be linked to S72.451K as the supporting diagnosis.

Nonunion coding follows the same pattern in other long bones, which is why S52.262K reads almost identically for the radius. Practices managing complex orthopedic cases benefit from structured HIPAA-compliant documentation workflows. Those workflows keep nonunion recorded consistently across visits, not only in the surgeon’s operative note.

Related ICD-10-CM codes: S72.451K in context

S72.451K sits within a large family of distal femur fracture codes. Knowing the adjacent codes helps coders verify laterality, displacement status, and encounter type at a glance. Sports medicine practices managing these injuries record diagnoses and billing detail in one place with sports medicine practice software.

Approximate synonyms and alternate clinical terms for S72.451K

Operative reports, radiology reads, and clinic notes rarely use the precise ICD-10-CM language. These alternate phrasings all map to ICD-10 Code S72.451K in the alphabetic index.

• Closed fracture of the supracondylar femur, right, with nonunion, subsequent encounter
• Fracture of lower end of right femur, supracondylar, displaced, nonunion
• Right distal femur fracture, supracondylar, closed, follow-up for nonunion
• Supracondylar fracture right femur without condylar involvement, nonunion, follow-up
• Failed healing of right supracondylar femoral fracture (closed), subsequent encounter
• Right femur distal fracture, above condyles, noncommunicating with joint, nonunion

When abstracting from radiology reports, look for phrases such as “fracture gap persists,” “no bridging callus,” or “pseudarthrosis formation.” These support the nonunion designation, but the physician still has to confirm it in the clinical assessment. According to the AAPC ICD-10-CM code reference, coders follow the physician’s documented judgment, not radiographic findings alone.

Documentation requirements for S72.451K

A missing laterality notation is one of the most common triggers for orthopedic fracture claim rejections. For ICD-10 Code S72.451K, seven documentation elements must appear in the clinical note or operative report before a coder can confidently assign this code.

• Laterality (right): The note must specify the right femur. “Femur fracture” without a side is not sufficient for S72.451K.
• Anatomical location (lower end / distal femur): “Femur fracture” alone could be a shaft fracture. The note must identify the distal or lower end.
• Fracture pattern (supracondylar): The treating physician or radiologist must characterize the fracture as supracondylar.
• Displacement status (displaced): Documented as displaced; fragments out of anatomical alignment.
• No intracondylar extension: The fracture line does not enter the condyles or joint surface. This may be stated as “no intraarticular extension” or confirmed by the surgical/imaging report.
• Encounter type (subsequent): This is not the first visit for active treatment of this injury.
• Fracture type and healing status (closed, nonunion): The fracture is closed and the physician has documented nonunion.

Practices running orthopedic follow-up programs benefit from structured patient record management that tracks visit type, fracture status, and imaging findings across the care episode. A consistent record structure makes each of these seven elements easy to locate at billing time.

Payer-specific requirements vary. Some insurers require imaging reports alongside the clinical note to support nonunion. Verify the payer’s documentation policy before a revision surgery, since obligations extend beyond the fracture code to the whole episode of care.

Commonly paired CPT codes and billing considerations

S72.451K rarely appears on a claim without a procedure code. Nonunion management requires active intervention, and each intervention has a corresponding CPT code. The table below covers the most frequently paired codes based on standard orthopedic nonunion treatment pathways.

Pre-authorization requirements for nonunion surgery vary by payer and plan. Check the individual plan’s current coverage policy rather than assuming a payer waives or requires it. Where the graft is harvested through a separate incision, the autograft rules that govern CPT 20938 are worth reading alongside 27472. According to the CDC ICD-10-CM web tool, S72.451K is valid for FY2026 claim submission.

Coding guidance: avoiding common errors with S72.451K

Three coding mistakes account for the majority of denials on S72.451K claims. Each one is preventable with the right workflow.

• Using D when nonunion is documented: If the clinical note says “nonunion” anywhere, use K instead of D for that encounter. Coders who default to D for every follow-up visit will consistently miscode nonunion encounters.
• Missing the “without intracondylar extension” qualifier: Radiology reports may describe a “distal femur fracture” without saying whether the fracture line enters the joint. Query the physician or review the operative report before choosing S72.451K over S72.441K.
• Incorrect laterality: S72.451K is right femur only. S72.452K is left. If the note says left or bilateral, the code changes. “Unspecified” (S72.459K) is acceptable only when laterality is genuinely not documented and cannot be determined.
• Using A (initial) for a follow-up visit: Some coders use A for every orthopedic visit at the same facility. ICD-10-CM guidelines are clear: A applies only when the patient is receiving active treatment for the fracture for the first time, including the first surgery. Post-operative visits get a subsequent encounter character.
• Confusing K (nonunion) with S (sequela): S is for the treatment of late effects after the fracture has healed. Nonunion means the fracture has not healed. These are mutually exclusive. Using S on a nonunion visit is incorrect and may suggest the fracture has resolved.

A structured pre-submission audit of orthopedic claims, filtered by S72.4x codes, usually reveals a pattern in encounter-type errors. Practices that route these claims through a dedicated review step see fewer denial cycles for this code family. Once the coder signs off, Pabau submits the claim electronically and reports its status back. A denial then surfaces in days rather than at month-end reconciliation. The WHO ICD-10 browser holds the international framework underlying the US version.

How Pabau supports orthopedic claim submission and follow-up

In most orthopedic practices, a nonunion claim passes through three disconnected systems. The physician’s note lives in the record, and the coder works from a printout or a separate abstract. The claim then goes out through a clearinghouse portal that nobody logs into daily. Denials surface weeks later, at reconciliation.

Pabau keeps those steps in one place. The clinical note, the imaging finding, and the coded claim sit against the same patient record. Eligibility is checked in real time before the visit. Our claims management software then submits the claim and reports its status back as the payer processes it.

The coder still owns the code choice. What changes is the feedback loop. A rejected S72.451K claim surfaces in days, while the encounter is fresh enough to correct. Our comparison of claims management software sets out how that submission path differs from a standalone clearinghouse.

Get orthopedic claims out and tracked to resolution

Pabau submits your claims electronically, checks patient eligibility in real time, and tracks every submission through to payer resolution. Your billing team sees where each S72.451K claim stands without leaving the patient record.

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Conclusion

The 7th character is the part of S72.451K worth defending. K is never a default value, and it holds only where the physician has written nonunion into the assessment. If the note is silent on healing status, the safe move is to query, not to guess between D and K.

Practices that build the healing-status check into their standard follow-up template stop making this error entirely, because the coder never has to infer it. The trade-off is one extra field on every orthopedic follow-up note. Practice management software can carry that field and the claim it feeds. Book a demo to see how Pabau handles orthopedic claim submission and tracking.

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