ICD-10 Code S59.031S: Salter-Harris Type III ulna sequela

Key takeaways

S59.031S is the billable ICD-10-CM code for sequela of a Salter-Harris Type III physeal fracture of the lower end of the right ulna

The parent code S59.031 is not billable. A claim needs one of its six 7th characters: A, D, G, K, P, or S

Use S59.031S only when the patient presents with a late effect of a prior fracture, not during active treatment or a subsequent healing visit

Pabau’s claims management software integrates with Claim.MD to check eligibility and submit clean claims for orthopedic and musculoskeletal encounters

ICD-10 Code S59.031S is a billable ICD-10-CM diagnosis code. It covers the sequela of a Salter-Harris Type III physeal fracture of the lower end of the right ulna.

The code applies once active treatment of that fracture has finished and the visit addresses a residual effect. The parent code S59.031 carries no 7th character, so a claim submitted with it is rejected before a payer reviews it.

Salter-Harris fractures are primarily a pediatric coding concern. These injuries occur at the growth plate (physis) of developing bones. The sequela stage captures long-term consequences such as growth arrest, angular deformity, or restricted range of motion. These can present months or years after the original fracture was treated.

ICD-10 Code S59.031S: definition and billable status

ICD-10 Code S59.031S is a billable ICD-10-CM diagnosis code, effective in the 2026 edition, confirmed by the CDC/NCHS ICD-10-CM web tool. The full clinical description is: Salter-Harris Type III physeal fracture of lower end of ulna, right arm, sequela.

The parent code S59.031 is non-billable on its own. A payer will reject any claim submitted without a valid 7th character extension. S59.031S is one of six valid child codes, each representing a different episode of care. Only the 7th-character versions are accepted for billing.

Understanding the ‘S’ suffix: sequela episode of care

In ICD-10-CM, the 7th character defines the episode of care, and the ‘S’ suffix carries a specific clinical meaning: sequela. Sequela refers to a late effect that remains after the acute phase of an injury or illness has resolved. There is no minimum time threshold in the CMS ICD-10-CM Official Guidelines for Coding and Reporting. The determining factor is clinical status, not calendar time.

The sequela code is used when the patient’s current visit is for a condition that is the direct consequence of a prior injury. For S59.031S, the patient presents with a complication or residual effect of a previously sustained Salter-Harris Type III fracture of the right distal ulna.

A common documentation error is using the sequela code during ongoing fracture management. If treatment is still directed at the fracture itself, S is the wrong character, and D, G, K, or P applies instead. The flow below maps each character to the phase of care it belongs to.

Sibling codes across all six 7th characters

S59.031 has six billable child codes. Each is valid for submission only with its 7th character appended. To look up any of them directly, use the AAPC ICD-10-CM code lookup.

Note that S59.031 without a 7th character is non-billable and will be rejected by payers. Always append the correct episode-of-care character before claim submission. A missing character is cheapest to catch pre-submission, which is where cleaner claims management pays for itself.

Clinical background: Salter-Harris Type III physeal fractures

Salter-Harris fractures are classified by the relationship between the fracture line and the growth plate (physis). A Type III fracture extends from the physis through the epiphysis, reaching the articular surface. Because the fracture crosses into the joint, anatomical reduction is critical. Displacement at the articular surface increases the risk of growth disturbance and long-term deformity.

These injuries predominantly occur in children and adolescents whose growth plates have not yet fused. The distal ulna physis is a recognized site for this fracture pattern, typically after a fall or sports-related wrist trauma.

Late complications such as premature physeal closure, angular deformity of the forearm, or residual joint incongruence are the conditions documented under the sequela code S59.031S.

Where the code sits in the ICD-10-CM hierarchy

Understanding the hierarchy helps coders navigate quickly and avoid selecting a non-billable parent code by mistake. S59.031S sits within the ICD-10-CM injury chapter as follows:

• S00-T88: Injury, poisoning, and certain other consequences of external causes
• S50-S59: Injuries to the elbow and forearm
• S59: Other and unspecified injuries of elbow and forearm
• S59.0: Physeal fracture of lower end of ulna
• S59.03: Salter-Harris Type III physeal fracture of lower end of ulna
• S59.031: Salter-Harris Type III physeal fracture of lower end of ulna, right arm (non-billable)
• S59.031S: Salter-Harris Type III physeal fracture of lower end of ulna, right arm, sequela (billable)

Left arm laterality follows the same hierarchy under S59.032, with S59.032S as the corresponding billable sequela code. Never use the right-arm code for a left-arm injury. Laterality errors are a leading cause of claim rejection on fracture codes.

Documentation requirements for a sequela claim

Submitting S59.031S requires documentation that establishes three things. The record has to show a prior fracture of the right distal ulna consistent with a Salter-Harris Type III injury. It also has to show active treatment of a condition caused by that fracture, and name the late effect being managed.

• Prior fracture history: Include the original fracture date, the initial treatment setting, and, where available, the ICD-10 code used during active treatment (S59.031A)
• Nature of the late effect: Specify the current condition, such as growth plate arrest, forearm angular deformity, joint incongruence, or restricted wrist range of motion
• Laterality confirmation: Explicitly state “right arm” or “right upper extremity” in the clinical note
• Link to the prior fracture: The note must causally tie the sequela to the original Salter-Harris injury, not to unrelated pathology
• Episode of care justification: Confirm that active fracture treatment is complete and the current visit is for management of residual effects only

Practices that submit sequela claims through a clearinghouse benefit from pre-submission editing. Those edits flag laterality mismatches and missing episode-of-care characters before the claim reaches the payer. For a broader view of the claims lifecycle, the submitting a clean claim guide explains the checks that matter most.

Related ICD-10 codes for ulna and forearm fractures

Coders working with S59.031S frequently need adjacent codes within the S59 category. The table below covers the ones referenced most often, and our ICD-10-CM code library covers the categories beyond it.

When the Salter-Harris type was not specified in the original medical record, S59.091S (other physeal fracture) is the appropriate fallback for a right arm sequela. Avoid assigning a specific type code without supporting documentation from the original treating clinician.

When to use S59.031S: clinical coding scenarios

These three scenarios cover the encounter types that come up most often in pediatric distal ulna physeal fracture cases. Each one follows the ICD-10-CM Official Guidelines published by CDC/NCHS and CMS.

1. Post-fracture deformity review, 14 months after the original injury: A 12-year-old attends an orthopedic outpatient appointment with visible radial bowing of the right forearm. Radiographs confirm physeal arrest at the distal ulna consistent with a prior Salter-Harris Type III injury. Active fracture treatment ended 10 months ago. The visit is to evaluate the growth disturbance and discuss corrective options. Use S59.031S, because the growth arrest and angular deformity are late effects of the prior fracture.
2. First post-operative visit after corrective osteotomy: The same patient returns two weeks after surgical correction of the forearm deformity. This visit involves active management of the surgical wound and monitoring of the osteotomy. The reason for surgery remains the sequela of the prior fracture. S59.031S continues to apply as the primary diagnosis, alongside the procedure codes for the surgical visit.
3. Therapy referral for restricted wrist range of motion: A 16-year-old is referred for occupational therapy. The referring note documents reduced wrist extension attributed to physeal scarring after a Salter-Harris Type III distal ulna fracture two years earlier. The fracture itself healed, so the restriction is a residual late effect. Use S59.031S.

When not to use S59.031S: Do not apply the sequela code while the patient is still being treated for the fracture itself. The same holds while the fracture is still healing, where D, G, K, or P fit instead. A presenting condition unrelated to the prior fracture takes its own code. The wrong episode-of-care suffix is one of the most audited errors in fracture coding.

How claims management software keeps sequela codes clean

A sequela claim usually fails for a small reason. The 7th character gets carried over from the initial encounter, or the laterality is typed from memory. The rejection then arrives weeks later, by which point the encounter is cold and the note is harder to reconstruct.

Practice management software like Pabau keeps the diagnosis code, the clinical note, and the claim on the same record. Pabau’s integration with Claim.MD checks patient eligibility in real time and submits the claim electronically. Payer responses come back against that encounter, so the coder sees exactly which character or laterality was refused.

For a practice managing post-fracture cases across years of follow-up, that history sits in one client record. The coder can see the initial encounter code, the treatment dates, and the note linking the residual condition to the original injury.

Reduce claim denials on orthopedic and musculoskeletal codes

Pabau integrates with Claim.MD to check patient eligibility in real time, submit claims electronically, and return each payer response against the encounter. Fewer rejections. Faster reimbursement.

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Conclusion

Sequela coding on physeal fracture cases turns on one judgment. Has active treatment of the fracture finished? Once it has, S59.031S is straightforward, since the descriptor, the laterality, and the billable status are all fixed.

That judgment is worth documenting in the note itself, not only in the code. A payer reading the record should see the original fracture, the current residual condition, and the causal line between them.

Pabau returns each payer response against the encounter that produced it, so a rejected sequela claim surfaces in days rather than at month end. Book a demo to see how Pabau handles diagnosis code submission for orthopedic caseloads.

Continue your research

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