ICD-10 code S59.229A: Salter-harris type II radius fracture

Key takeaways

ICD-10 code S59.229A covers a Salter-Harris Type II physeal fracture of the lower end of the radius, unspecified arm, initial encounter for closed fracture.

S59.229A is a billable, specific ICD-10-CM diagnosis code valid for the 2025 and 2026 fiscal years, effective October 1, 2025.

The 7th character A marks an initial encounter during active treatment. Use D for subsequent encounters and S for sequela.

ICD-10-CM has no dedicated Salter-Harris Type V code family, so crush injuries at this site are reported under S59.299.

Practice management software like Pabau helps orthopedic and pediatric practices file fracture claims with the right encounter type and laterality.

ICD-10 code S59.229A is a billable diagnosis code for a Salter-Harris Type II physeal fracture of the lower end of the radius. It covers an initial encounter for a closed fracture where the treated arm was not documented. The code is valid for all HIPAA-covered transactions in fiscal year 2026.

S59.229A sits in category S59, which covers other and unspecified injuries of the elbow and forearm. Coders in orthopedic, pediatric, and urgent care settings reach for it often. Distal radial physeal fractures are among the most common pediatric skeletal injuries. The table below carries the details you need before the claim goes out.

What each part of the S59.229A descriptor means

Each segment of the descriptor carries a specific clinical and administrative meaning. Get one segment wrong and you have a different code with different reimbursement consequences.

• Salter-Harris Type II: The fracture crosses the physis, or growth plate, and extends into the metaphysis. It spares the epiphysis. Type II is the most common Salter-Harris pattern, accounting for roughly 75% of growth plate fractures.
• Physeal fracture: Another name for a growth plate fracture. The physis is the cartilaginous disc in a growing bone that drives its length. Physeal fractures therefore occur only in skeletally immature patients.
• Lower end of radius: The distal radial physis, just above the wrist joint. This is the site most often affected when a child falls onto an outstretched hand.
• Unspecified arm: Laterality was not documented at the time of coding. Query the provider for right or left wherever you can. S59.229A is appropriate only when laterality is genuinely unknown or unrecorded.
• Initial encounter: The patient is receiving active treatment. Under ICD-10-CM guidelines, that covers every visit while active treatment continues, not only the first one.
• Closed fracture: The skin over the fracture site is intact. ICD-10-CM defaults to closed when the record does not say. S59.229A therefore also covers a documented physeal fracture with no stated wound status.

Pediatric orthopedic practices can catch most of these errors before the claim leaves the building. Claims management software validates the encounter type and laterality fields at submission.

How the Salter-Harris classification maps to ICD-10 codes

ICD-10-CM builds the Salter-Harris type into the code itself. Choose Type I instead of Type II and you have selected a different code. That affects medical necessity documentation and, under some payer edits, reimbursement for the associated procedures.

ICD-10-CM has no dedicated Type V code family. S59.299 is titled “Other specified physeal fracture of lower end of radius”. A crush injury at this site is reported under that code rather than a Type V code.

Type II is by far the most common pattern. The imaging report should state the Salter-Harris classification to support the code you pick. When the record says only “physeal fracture” with no type, query the provider before you assign a type-specific code.

Not every pediatric radius fracture involves the growth plate. Buckle and bowing injuries sit elsewhere in ICD-10-CM, under codes such as S52.529D and S52.389A.

7th character extensions for S59.229

The 7th character is the most frequently miscoded element on Salter-Harris fracture claims. Using A at a routine follow-up, or forgetting to switch to D once treatment has stabilized, produces claim errors. Those errors trigger audits under CMS ICD-10-CM guidelines.

When to use S59.229A, S59.229D, or S59.229S

The shift from A to D does not happen after a set number of visits or weeks. It happens when the provider’s notes show the patient is no longer in active treatment. The same test governs every 7th character in the elbow and forearm chapter, including sprain codes such as S53.442D.

A child seen three times in a cast is coded A on every visit while the provider is still actively managing the injury. Once the cast is off and the child is in standard follow-up, switch to D.

Sequela applies when the late effect becomes the reason for the visit, separate from the original injury. A teenager presenting months later with growth arrest would carry S59.229S alongside the code for the presenting condition.

Practices running high-volume orthopedic follow-up can lean on automated clinical workflows here. A workflow prompts the coder to reassess the encounter type at each scheduled interval.

S59.229A code hierarchy and parent codes

Knowing where S59.229A sits in the ICD-10-CM hierarchy helps you pick the right level of specificity. It also shows which excludes notes govern the code.

• S00-T88: Injury, poisoning and certain other consequences of external causes
• S50-S59: Injuries of the elbow and forearm
• S59: Other and unspecified injuries of elbow and forearm
• S59.2: Physeal fracture of lower end of radius
• S59.22: Salter-Harris Type II physeal fracture of lower end of radius
• S59.229: Salter-Harris Type II physeal fracture of lower end of radius, unspecified arm
• S59.229A: Initial encounter for closed fracture, which is this code

The “unspecified arm” designation at the S59.229 level means laterality was never captured. The laterality-specific siblings are S59.221 for the right arm and S59.222 for the left. Each carries the same 7th character options, so always code laterality when it is documented.

Per the CDC/NCHS ICD-10-CM coding tool, using an unspecified code when laterality is in the record counts as a coding quality deficiency. It can affect quality metrics and invite payer audits.

For pediatric orthopedic caseloads, capturing the treated side at intake removes most of that risk. Digital intake forms that prompt for body side cut the downstream need to recode.

Related ICD-10 codes to know alongside S59.229A

Mis-coding between Salter-Harris types, and between laterality variants, is the most common error pattern for this code family. The table below covers the codes most often confused with S59.229A, or needed alongside it.

The crosswalk between S59.229A and S52.509A is a common point of confusion. S52.509A sits under a different parent category, S52, and is not Salter-Harris typed. Use it only when the fracture is at the distal radius and the record does not support a Salter-Harris classification.

When the late effect of a lower-radius fracture is itself the reason for the visit, a sequela code such as S52.591S may apply instead.

CPT codes commonly billed with S59.229A

S59.229A is a diagnosis code. Treating the fracture itself requires one or more CPT procedure codes on the same claim. The codes below are commonly associated with distal radius physeal fractures in children. Pairing depends on the procedure performed and on payer coverage.

Verify your pairings against AAPC’s ICD-10-CM reference and the relevant LCD policies before you submit.

CPT-ICD-10 pairings for pediatric fractures are subject to National Correct Coding Initiative edits, known as NCCI. CPT 25605 and 25606 bundle certain supply and anesthesia codes, for example. A forearm shaft injury treated at the same visit falls to a separate code such as 25565.

Follow-up visits are usually billed with an evaluation and management code such as 99213. Practices running orthopedic rehabilitation services should check whether post-reduction therapy codes are separately billable under the payer’s global period rules.

ICD-10-CM guidelines that govern S59.229A

Three sections of the ICD-10-CM Official Guidelines govern how S59.229A is assigned. Misapply any one of them and an audit will find a coding error.

• Default to closed (Section I.C.19.a): When the record does not say whether a fracture is open or closed, ICD-10-CM instructs you to default to closed. S59.229A is therefore correct when the note reads only “distal radius physeal fracture”.
• Encounter type follows active treatment (Section I.C.19): “Initial encounter” is not the same as the patient’s first visit. The A extension applies for as long as active treatment continues. A child in a cast attending weekly check-ups is still in active treatment. Switch to D once treatment has concluded and the patient is in routine healing.
• Code to the specificity the record supports: If imaging classifies the fracture as Salter-Harris Type II, use S59.229A rather than the unspecified parent S59.209A. If laterality is documented, use S59.221A or S59.222A instead.
• Sequencing with external cause codes: S59.229A is usually sequenced as the principal diagnosis. Follow it with an external cause code, such as a fall from a playground structure, and a place-of-occurrence code where one applies.

Practices coding pediatric fractures every week can build these rules into the encounter record itself. Sports medicine software ties documentation prompts to the clinical note. The coder then sees a missing element while the patient is still in the room.

Documentation requirements to support S59.229A

Billable status and documentation sufficiency are separate questions. S59.229A is billable, but the claim will not survive an audit unless the record supports each part of the descriptor.

• Imaging report with Salter-Harris classification: The X-ray or MRI report must state the Salter-Harris type. A report reading “distal radius fracture” with no type does not support a type-specific code. Wording such as “fracture through the physis with metaphyseal extension” does.
• Anatomical site: The record must confirm the fracture is at the lower end of the radius, not the mid-shaft or the proximal radius. “Wrist fracture” on its own is not enough.
• Open or closed status: Documentation of skin integrity at the fracture site decides whether A is the right extension. If the wound is open, a different code family applies.
• Laterality: The record should state which arm is affected. If the note says “right wrist fracture”, the coder must move to S59.221A. Using the unspecified-arm code when laterality is on file is a documentation mismatch.
• Encounter type justification: The note must show active treatment on the visit date to support the A extension. A note reading “fracture healing well, return in 4 weeks” may sit in D territory, depending on payer policy.

Structured client records let you standardize how Salter-Harris type, laterality, and wound status are captured at the point of care. That cuts the number of queries a coder has to raise with the provider afterwards.

ICD-9-CM to ICD-10-CM crosswalk for S59.229A

Practices migrating historical records or reconciling pre-2015 claims may need to map legacy ICD-9-CM codes to S59.229A. Crosswalks between ICD-9 and ICD-10 are approximate. A single ICD-9 code sometimes maps to several ICD-10 codes, depending on documentation specificity.

Verify any mapping against the ResDAC ICD code reference before you use it for claims reconciliation.

ICD-9-CM did not carry Salter-Harris specificity in its fracture codes. Any crosswalk to S59.229A needs confirmation from the underlying documentation that Type II was established at the original encounter. Do not apply the type-specific ICD-10 code retroactively without that support.

Client management tools can store coding history alongside the clinical record. That keeps each migration decision auditable long after the project closes.

How Pabau keeps pediatric fracture claims accurate

In most practices, the three elements that decide this code live in three places. The Salter-Harris type sits in a radiology report. The treated side sits in a nurse’s note. The encounter stage sits in the provider’s plan, and the coder assembles all three by hand.

Practice management software like Pabau holds those elements on one client record. Intake forms capture the treated side at check-in. Charting templates keep the Salter-Harris type and wound status as structured fields rather than free text. Claims tools flag an encounter character that no longer matches the note.

The result is fewer queries back to the provider, and fewer claims returned for laterality or encounter-type errors. Your coders spend their time on the claims that genuinely need judgment.

Manage orthopedic and pediatric claims with confidence

Pabau's claims tools help orthopedic and pediatric practices submit accurate ICD-10-CM fracture codes and track encounter types. That cuts denials caused by laterality and 7th-character errors.

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Conclusion

S59.229A is easy to assign and easy to defend, provided the record does the work first. The code is rarely the problem on a denied pediatric fracture claim. The missing Salter-Harris type, or the laterality nobody wrote down, usually is.

So treat the unspecified-arm variant as a fallback rather than a default. Every time you reach for it, ask whether the answer is already sitting somewhere in the chart. That habit is worth more to your denial rate than any code lookup.

Book a demo to see how Pabau helps orthopedic and pediatric practices file fracture claims that hold up on audit.

Continue your research

Need a fast reference across code sets? Medical coding cheat sheet pulls the ICD-10, CPT, and HCPCS conventions your team checks most often into one printable page.

Reporting a late effect in the forearm? S56.529S shows how the sequela extension works when the residual problem, not the injury, brings the patient in.

Seeing a torus fracture higher up the radius? S52.119S covers the upper-end torus pattern that coders often confuse with a distal physeal injury.

Managing rehab once the cast comes off? Home exercise program template gives you a structured plan to hand the patient at the end of active fracture treatment.

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