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

Key takeaways

In short, S72.451K is a billable ICD-10-CM code for a displaced supracondylar fracture of the lower right femur. That is, it applies at subsequent encounters when nonunion is noted.

In fact, the 7th character K marks a follow-up encounter for a closed fracture that has failed to heal. As such, it keeps this code apart from D for routine healing and S for sequela.

Put simply, without intracondylar extension means the fracture line does not cross the joint surface into the condyles. So, that puts the code in the S72.451 family rather than the condylar families.

In practice, Pabau, an all-in-one practice management system, submits orthopedic claims online, runs real-time coverage checks, and tracks each claim through to a payer outcome.

ICD-10 Code S72.451K: Quick reference

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

Broadly, this reference covers the full code description, the complete 7th-character set, nearby codes, and documentation needs. Last, it closes with the coding errors that most often send these claims back.

Quick reference table

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

In fact, every word in the full description of ICD-10 Code S72.451K carries coding weight. Indeed, misread any part and you land on another code. Here is what each part means:

What each part of the code means

• Displaced: In fact, the fracture fragments have moved out of their normal position. By contrast, in nondisplaced (S72.461K), the bone cracks but stays in place.
• Supracondylar: Here, the fracture occurs in the distal femur, above the femoral condyles. As a result, it does not involve the condylar joint surfaces themselves.
• Without intracondylar extension: Put simply, the fracture line does not extend into the condyles or the knee joint surface. As a result, this is the key marker that keeps S72.451K apart from intercondylar and condylar fracture codes. For more on why this matters, see the anatomy section below.
• Lower end of right femur: Names the place (distal femur) and side (right). So, the left version is S72.452K.
• Subsequent encounter: Indeed, this is not the patient’s first visit for this injury. Rather, the acute phase is over and the patient is in active follow-up or ongoing management.
• Closed fracture: Simply, the skin is intact over the fracture site. In other words, there is no open wound connecting to the fracture.
• Nonunion: In short, the bone has failed to heal within the expected timeframe. So, the 7th character K marks this specific problem.

Why complete documentation matters

First, a coder working from an operative or clinic note needs all seven of these details noted to support S72.451K. If any one of them is missing, mainly laterality or the nonunion status, payers will question the code. Even so, practice management software like Pabau submits the finished claim online and reports its status back. As a result, an incomplete record shows up as a payer reply you can act on.

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

In practice, how supracondylar differs from intracondylar is something coders and clinicians often mix up. Still, knowing the anatomy makes the coding choice simple.

The anatomy explained

So, the distal femur widens as it approaches the knee and splits into two rounded parts: the medial and lateral condyles. The spot just above this split, where the femoral shaft turns into the condylar flare, is the supracondylar zone. As a result, a fracture here stays close to the joint surface.

Clinical and coding impact

Indeed, supracondylar fractures without intracondylar extension are common in high-energy trauma and in older patients with osteoporosis. In these cases, orthopedic teams use physical therapy practice software to track rehab across post-op visits. This detail also matters for surgery planning, since a fracture that enters the joint needs a different operation. As a result, a medial condyle fracture coded as S72.431C sits in its own family.

Understanding the 7th character K: subsequent encounter for nonunion

How the 7th character works

In fact, the 7th character in ICD-10-CM fracture codes does the heaviest lifting. That is, for any S72.451x code, it tells the payer just where the patient is in their fracture care journey. As a result, getting this wrong is the most common reason these claims are denied.

Indeed, fracture codes are more complex than most ICD-10-CM code groups because S72.451 takes 16 different 7th characters. Of these, six cover closed fractures and sequela, while the other ten cover open fractures, split by Gustilo type. Likewise, 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 appears in the next section.

When to use K

• K applies when: First, the patient is seen after the acute fracture event, at a subsequent encounter. Also, imaging or a clinical check shows that the fracture has not united within the expected period.
• K does not apply when: Here, the fracture is healing normally (D) or slowly (G). Nor does it apply while the acute injury is still being checked (A, B, or C). Instead, for an open fracture with nonunion, use M or N.
• K vs D in practice: In fact, many practices switch from D to K too late. Indeed, the encounter code changes to K the moment the doctor notes «nonunion» or «failed healing» in the note. Elapsed time, in other words, does not matter.

In fact, ICD-10-CM Official Guidelines set no fixed timeline for nonunion. Instead, the call rests with the treating doctor, backed by imaging. Note it clearly, and the K character is supported; without that note, though, payers will question the code.

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

In short, S72.451 is the 6-character parent for displaced supracondylar fractures without intracondylar extension of the lower end of the right femur. Beyond that, the 7th character sets the complete, billable code. All 16 valid characters are listed below, plus the open-fracture characters that many coding guides leave out.

Full 7th-character table

How the 7th character is assigned

Per the CMS ICD-10-CM coding guidelines, the 7th character reflects the status of the fracture at the time of the encounter, not how far along treatment is. For instance, a new injury seen in the emergency department always takes the A character, and that holds even at the hospital that treated the patient’s previous fracture.

What is fracture nonunion? Clinical and coding implications

Clinical signs of nonunion

Put simply, nonunion means the fracture has not healed and is unlikely to heal on its own. As such, it is a clinical diagnosis, confirmed by imaging, and it changes both the treatment plan and the coding approach.

On imaging, nonunion often shows a lasting fracture gap, sclerosis of the fracture ends, or the formation of a pseudarthrosis (a false joint). Clinically, meanwhile, the patient often reports ongoing pain at the fracture site and, in weight-bearing bones like the femur, trouble walking.

Coding nonunion correctly

• Documentation trigger: First, the doctor must clearly note «nonunion» or similar wording («failed fracture healing,» «absent bridging callus on imaging») in the clinical note. In other words, coders cannot infer K from elapsed time alone.
• Coding implication: Once nonunion is noted, K replaces D on every subsequent encounter for this injury. This holds true until the fracture unites or the patient is treated for sequela.
• Treatment context: In practice, nonunion care often involves bone grafting, revision fixation, or bone stimulation. So, each procedure has its own CPT code and should be linked to S72.451K as the diagnosis it supports.

Nonunion coding follows the same pattern in other long bones, which is why S52.262K reads almost the same way for the radius. Given this pattern, practices that manage hard orthopedic cases gain from structured HIPAA-compliant documentation workflows. In turn, those workflows keep nonunion recorded every time across visits, not only in the surgeon’s operative note.

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

In fact, S72.451K sits within a large family of distal femur fracture codes. As such, knowing the nearby codes helps coders check laterality, displacement status, and encounter type at a glance. Sports medicine practices that manage these injuries, for instance, record diagnoses and billing detail in one place with sports medicine practice software.

Codes to compare against S72.451K

Approximate synonyms and alternate clinical terms for S72.451K

In practice, operative reports, radiology reads, and clinic notes rarely use the precise ICD-10-CM language. Still, these other phrasings all map to ICD-10 Code S72.451K in the alphabetic index.

Common phrasings that map to this code

• 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 reading radiology reports, look for phrases such as «fracture gap persists,» «no bridging callus,» or «pseudarthrosis formation.» These support the nonunion label, but the doctor still has to confirm it in the clinical check. Indeed, per the AAPC ICD-10-CM code reference, coders follow the doctor’s stated judgment, not imaging findings alone.

Documentation requirements for S72.451K

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

The seven required elements

• Laterality (right): First, the note must state the right femur. If not, «femur fracture» without a side is not enough for S72.451K.
• Location (lower end / distal femur): In fact, «Femur fracture» alone could be a shaft fracture. So, the note must name the distal or lower end.
• Fracture pattern (supracondylar): Also, the treating doctor or radiologist must call the fracture supracondylar.
• Displacement status (displaced): Noted as displaced; fragments out of normal position.
• No intracondylar extension: Again, the fracture line does not enter the condyles or joint surface. Or, this may be stated as «no intraarticular extension» or confirmed by the surgical/imaging report.
• Encounter type (subsequent): Simply, this is not the first visit for active treatment of this injury.
• Fracture type and healing status (closed, nonunion): In short, the fracture is closed and the doctor has noted nonunion.

Indeed, practices running orthopedic follow-up programs gain from structured patient record management that tracks visit type, fracture status, and imaging findings over the course of care. As a result, a steady record structure makes each of these seven items easy to find at billing time.

Payer-specific documentation rules

Payer-specific rules vary; for instance, some payers require imaging reports along with the clinical note to support nonunion. So, check the payer’s documentation policy before a revision surgery, since duties go beyond the fracture code to the whole span of care.

Commonly paired CPT codes and billing considerations

In fact, S72.451K rarely appears on a claim without a procedure code. After all, nonunion care needs active treatment, and each treatment step has a matching CPT code. So, the table below covers the most often paired codes based on standard orthopedic nonunion treatment paths.

CPT codes commonly paired with S72.451K

Indeed, prior auth rules for nonunion surgery vary by payer and plan. So, check the individual plan’s current coverage policy rather than assuming a payer waives or requires it. Also, where the graft is taken through a second cut, the autograft rules that govern CPT 20938 are worth reading along with 27472. Note, per the CDC ICD-10-CM web tool, S72.451K is valid for filing FY2026 claims.

Coding guidance: avoiding common errors with S72.451K

In fact, three coding mistakes account for most of the denials on S72.451K claims. Still, each one is easy to prevent with the right workflow.

The five most common coding errors

• Using D when nonunion is noted: If the clinical note says «nonunion» anywhere, use K instead of D for that encounter. But coders who default to D for every follow-up visit will often miscode nonunion encounters.
• Missing the «without intracondylar extension» tag: Often, radiology reports may describe a «distal femur fracture» without saying whether the fracture line enters the joint. In that case, ask the doctor or check the operative report before choosing S72.451K over S72.441K.
• Wrong laterality: S72.451K is right femur only, while S72.452K is left. If the note says left or bilateral, the code changes too. «Unspecified» (S72.459K) is fine only when laterality is truly not noted and cannot be figured out.
• Using A (initial) for a follow-up visit: In practice, some coders use A for every orthopedic visit at the same facility. But ICD-10-CM guidelines are clear: A applies only when the patient is getting active treatment for the fracture for the first time, plus the first surgery. Instead, post-op 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, while nonunion means the fracture has not healed. So the two never go together. Using S on a nonunion visit, as a result, is wrong and may suggest the fracture has healed when it has not.

In practice, a structured pre-submission check of orthopedic claims, sorted by S72.4x codes, usually reveals a pattern in encounter-type errors. So, practices that route these claims through a set review step see fewer denial cycles for this code family. Once the coder signs off, Pabau submits the claim online and reports its status back, so a denial then shows up in days rather than at month-end review. For context, the WHO ICD-10 browser holds the international framework behind the US version.

How Pabau supports orthopedic claim submission and follow-up

The problem: disconnected systems

In most orthopedic practices, a nonunion claim passes through three disconnected systems. First, the doctor’s note lives in the record, and the coder works from a printout or their own summary. Next, the claim goes out through a clearinghouse portal that nobody logs into daily. As a result, denials show up weeks later, at review time.

How Pabau closes the gap

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

Indeed, the coder still owns the code choice; what changes is the feedback loop. As a result, a rejected S72.451K claim shows up in days, while the encounter is still fresh enough to fix. For more detail, our comparison of claims management software sets out how that filing path differs from a standalone clearinghouse.

Get orthopedic claims out and tracked to the end

In practice, Pabau submits your claims online, checks patient coverage in real time, and tracks every claim through to a payer outcome. Your billing team sees where each S72.451K claim stands without leaving the patient record.

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Conclusion

The bottom line

In short, the 7th character is the part of S72.451K worth defending. Indeed, K is never a default value, and it holds only where the doctor has written nonunion into the note. So, if the note is silent on healing status, the safe move is to ask, not to guess between D and K.

Making it stick

Practices that build the healing-status check into their standard follow-up template stop making this error for good, because the coder never has to guess at it. In exchange, 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. To see how Pabau handles orthopedic claim filing and tracking, book a demo.

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