ICD-10 Code S62.185K: Nondisplaced trapezoid fracture, left wrist

Key takeaways

S62.185K is a billable ICD-10-CM code for a nondisplaced trapezoid fracture with nonunion, unspecified wrist. It is valid for reimbursement from October 1, 2025.

The 7th character K specifies a subsequent encounter where the fracture has failed to unite. That makes it distinct from G for delayed healing and P for malunion.

Use S62.185K only when laterality is genuinely undocumented. Defaulting to unspecified wrist when the side is known triggers payer audits.

Most payers expect an external cause code from the V00-Y99 range alongside the fracture diagnosis.

Practice management software like Pabau puts ICD-10-CM code search inside the billing workflow, so coders catch encounter-type errors before submission.

ICD-10 Code S62.185K is a billable code for a nondisplaced fracture of the trapezoid, unspecified wrist, at a subsequent encounter with nonunion. It applies once the provider documents that the fracture has failed to unite.

This reference covers the full description, billable status, 7th character rules, adjacent codes, and common coding errors. It also sets out the clinical scenarios that separate S62.185K from the rest of the S62.185 family.

ICD-10 Code S62.185K: Definition and billable status

S62.185K is a billable, specific ICD-10-CM code valid for use in HIPAA-covered electronic transactions. The 2026 edition became effective October 1, 2025.

The full description reads: Nondisplaced fracture of trapezoid, unspecified wrist, subsequent encounter for fracture with nonunion. Every component of that description carries coding weight.

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

Knowing where S62.185K sits in the S62 block helps coders select the correct specificity level. Anyone who already codes S52.262K will recognize the same branching pattern here.

• S00-T88 – Injury, poisoning and certain other consequences of external causes (chapter)
• S60-S69 – Injuries to the wrist and hand (block)
• S62 – Fracture of wrist and hand
• S62.1 – Fracture of other carpal bone(s)
• S62.18 – Fracture of trapezoid [smaller multangular]
• S62.185 – Nondisplaced fracture of trapezoid, unspecified wrist
• S62.185K – Subsequent encounter for fracture with nonunion

The hierarchy confirms that S62.185K is a fully specified, terminal node. No further code extension is required or available. Per CMS ICD-10-CM guidance, coders must always assign the most specific code available.

Understanding the diagnosis: Nondisplaced trapezoid fracture with nonunion

The trapezoid is one of eight carpal bones, positioned in the distal row of the wrist between the trapezium and the capitate. It articulates primarily with the second metacarpal, which makes it critical for hand stability during gripping and pinch.

Three clinical concepts combine in S62.185K:

• Nondisplaced: The fracture fragments have not shifted from their anatomical position. Bone alignment is maintained, but the fracture line is present. Displaced fractures, by contrast, show fragments that separate or override.
• Unspecified wrist: Laterality is not documented in the clinical record. This qualifier belongs only in records that genuinely lack a left or right designation. It is not a convenient default.
• Fracture with nonunion: The fracture has failed to achieve bony union within the expected healing timeframe. The bone ends remain mobile, or fibrous tissue forms in place of callus. Nonunion usually becomes the working diagnosis after 3 to 6 months without healing progress, though the threshold varies by fracture type and patient.

Clinically, trapezoid nonunion often follows a missed initial diagnosis. The trapezoid overlaps with adjacent carpal bones on plain radiographs. Fractures are frequently identified only on CT or MRI, sometimes months after the original injury.

What does the 7th character K mean in ICD-10 Code S62.185K?

The 7th character encodes both the encounter type and the healing complication, which makes it the most consequential part of the code. Fracture codes in the S00-T88 chapter require it to indicate whether the encounter is initial, subsequent, or a sequela.

The letter K specifically indicates a subsequent encounter for fracture with nonunion. That separates it from routine follow-up, delayed healing, malunion, and sequelae.

7th character options for S62.185: Full comparison

The distinction between G and K is not merely semantic. Payers apply different medical necessity thresholds to each. Nonunion typically justifies surgical intervention, while delayed healing does not. Assigning G when the fracture has definitively failed to unite can trigger a denial on a bone grafting claim.

Adjacent and related ICD-10-CM codes

The S62.185 family covers one fracture site across six encounter and complication types. Broader carpal coding requires moving up the hierarchy. Coders working in physical therapy EMR and sports medicine software environments cross-reference these adjacent codes constantly.

ICD-10-CM coding guidelines for S62.185K

The ICD-10-CM Official Guidelines for Coding and Reporting govern several rules that directly affect S62.185K assignment. Practices running HIPAA-compliant practice software can build these rules into claim scrubbing, which is where most medical billing teams catch them.

• Open vs. closed fracture default: When documentation does not specify open or closed, ICD-10-CM guidelines default to closed. The S62.185 codes reflect that default. No separate open-fracture code is needed unless the record states the fracture was open.
• Laterality and “unspecified”: The unspecified wrist qualifier is appropriate only when the medical record genuinely lacks laterality documentation. Coders should query the provider before defaulting to it.
• Subsequent encounter definition: A subsequent encounter is any visit after active treatment has begun. The patient does not need to see a different provider. Post-operative visits, cast checks, and bone stimulator follow-ups all qualify.
• Nonunion vs. delayed healing: Nonunion requires a clinical determination that union will not occur without intervention. Delayed healing describes slow but ongoing union. The provider’s documentation drives the choice between K and G, not elapsed time alone.
• External cause codes: Many payers require an external cause code from the V00-Y99 range alongside S62.185K. The external cause identifies how the original fracture occurred. Omitting it invites additional information requests.
• Sequencing: S62.185K may serve as a principal diagnosis when the nonunion is the main reason for the encounter. It may also be secondary when another condition drives the visit and the nonunion is an active comorbidity.

When to use S62.185K: Clinical scenarios

S62.185K applies in a narrower set of circumstances than coders sometimes assume. The following scenarios are correct use cases, and they follow the same subsequent-encounter logic as S61.441D.

• Orthopedic review of confirmed nonunion: A patient seen 5 months after an initial nondisplaced trapezoid fracture returns with persistent wrist pain. CT confirms absence of bony bridging, and the orthopedist documents nonunion. This subsequent encounter uses S62.185K.
• Pre-operative planning for bone grafting: The surgeon documents nonunion as the indication for a planned corticocancellous bone graft. S62.185K is the principal diagnosis on the claim.
• Physical therapy for wrist stabilization pending surgery: The therapist is treating wrist weakness and pain secondary to a documented trapezoid nonunion. S62.185K codes the associated diagnosis alongside the therapy treatment codes.
• Pain management consultation: A patient presents to a pain specialist with wrist pain from an established nonunion. The specialist’s notes confirm the underlying fracture nonunion, so S62.185K applies as a secondary code.

S62.185K does not apply to the initial injury visit, which takes S62.185A. Routine follow-up with normal healing takes S62.185D. A fracture that healed in poor alignment takes S62.185P.

Common coding errors to avoid with S62.185K

Several recurring mistakes appear in audits of the S62.185 code family. These are the ones most likely to trigger denials or corrective action. When reviewing practice management software features, look for claim scrubbing logic that addresses each one.

• Using S62.185A for ongoing care: The initial encounter code applies only during active treatment of a new fracture. Once treatment is established and the patient returns, a subsequent encounter code must replace it. Continued use of S62.185A is a common audit finding.
• Confusing K with G: Delayed healing implies the repair process is occurring but slowly. Nonunion means the fracture has definitively failed to unite. Using G when the provider has documented nonunion understates severity and can cause surgical denials.
• Confusing K with P: Nonunion means no union has occurred. Malunion means union did occur, but in a deformed position. Assigning K when imaging shows union in poor alignment creates a medical necessity mismatch on corrective osteotomy claims.
• Omitting the external cause code: Many commercial payers and Medicare Advantage plans require a V00-Y99 code with traumatic fracture diagnoses. Submitting S62.185K without one may generate an information request or a denial.
• Defaulting to “unspecified wrist” unnecessarily: If the record documents the affected side, coders must use S62.183K for the right wrist or S62.184K for the left. Choosing the unspecified code anyway is a specificity error and a frequent audit target.

Approximate synonyms and index terms

The following terms map to S62.185K in the ICD-10-CM Alphabetic Index. They are accepted alternate descriptions for documentation and coding purposes, and AAPC lists them as recognized index entries.

• Nondisplaced fracture of trapezoid, unspecified wrist, subsequent encounter for fracture with nonunion
• Fracture of os trapezoideum, nondisplaced, unspecified wrist, nonunion, subsequent encounter
• Nondisplaced trapezoid fracture with failed union, unspecified wrist
• Carpal trapezoid nondisplaced fracture, nonunion, subsequent visit
• Wrist NOS nondisplaced trapezoid fracture, nonunion, follow-up

How Pabau supports accurate coding for musculoskeletal practices

Assigning S62.185K correctly takes more than a code lookup. The coder has to confirm encounter type, healing status, laterality, and whether an external cause code is required.

All of that comes from a clinical note written under time pressure, which is why clinical documentation software matters as much as the code book.

Practice management software like Pabau puts ICD-10-CM code search inside the billing workflow. Coders search by code number or description, review the code without leaving the claim screen, and flag anything that needs more documentation before submission.

Pabau’s claims management software and patient record management tie clinical notes to billing records. The healing status the provider documented is visible to the coder at the moment the claim is built. K-versus-G and unspecified-versus-specific errors surface before submission rather than after a denial.

Reduce ICD-10 coding errors in your practice

Pabau connects clinical documentation to billing in one platform. Your coders always have the encounter type, laterality, and healing status they need to assign codes like S62.185K accurately.

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Conclusion

Nonunion is the clinical event that makes S62.185K correct rather than S62.185D or S62.185G. Before you submit, read the note for two things: a documented failure to unite, and a documented side. Those two facts decide the whole code.

Get them right and the surgical authorization goes through on the first pass. Get them wrong and the claim comes back weeks later, with the patient still waiting on grafting. The trade-off worth remembering is that a provider query costs minutes, while a denial costs a revision cycle.

Book a demo to see how Pabau keeps encounter type, laterality, and healing status in front of your coders as they build each claim.

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