ICD code S42.002G – Left clavicle fracture with delayed healing

Key takeaways

S42.002G is a billable ICD-10-CM code for a fracture of an unspecified part of the left clavicle at a subsequent encounter with delayed healing.

The 7th character G means delayed healing. Routine healing takes D, nonunion takes K, and an initial visit for a closed fracture takes A.

The chart has to show the delay itself, such as slow callus formation or a persistent fracture line on follow-up imaging.

Aftercare Z codes (Z47.xx) are not used for fracture follow-up in ICD-10-CM. The subsequent encounter character does that job.

Pabau’s claims management software integrates with Claim.MD to streamline electronic fracture claim submission and denial tracking.

ICD-10 Code S42.002G: Code details and quick reference

ICD-10 Code S42.002G is a valid, billable ICD-10-CM code in the FY2027 code set, effective October 1, 2026. Its full official descriptor is: Fracture of unspecified part of left clavicle, subsequent encounter for fracture with delayed healing.

Coders assign it at a follow-up visit when the provider documents that the fracture is healing more slowly than expected.

The code sits within the S42.00 subgroup, which covers fractures of an unspecified part of the clavicle. The parent code S42.002 is not billable on its own, because the full 7-character code is required on a claim. According to the CMS ICD-10-CM code set, every code in the S42 category needs a 7th character to be complete.

Understanding the 7th character G in ICD-10 fracture codes

The 7th character G means the patient is back for a subsequent encounter and the fracture is healing more slowly than expected. That is delayed healing. The fracture is still expected to unite, but it is behind the usual timeline.

S42 follows the standard ICD-10-CM fracture convention used across Chapter 19. A and B cover the initial encounter, D covers routine healing, and G covers delayed healing. K, P and S cover nonunion, malunion and sequela. The full set for S42.002 is shown below.

Per ICD-10-CM Official Guidelines Section I.C.19.a, the subsequent encounter characters apply once active treatment has ended. The patient is then receiving routine care during the healing or recovery phase.

Which of D, G, K or P applies depends on what the provider documents about healing at that visit. The decision below walks through each question in order.

Delayed healing vs routine healing vs nonunion

These three characters describe points on the same healing timeline, so the provider’s wording decides the code. Coders should not infer the healing status from the visit count or from pain alone.

• D (routine healing): The note says the fracture is healing as expected, with callus formation and alignment on track for the time since injury.
• G (delayed healing): The provider documents slower-than-expected union, such as limited callus or a fracture line still visible on follow-up imaging.
• K (nonunion): The provider states the fracture has failed to unite. Nonunion is a clinical diagnosis, so the coder needs that explicit statement before assigning K.

A fracture can move between these characters over the course of care. A patient coded with D at the first follow-up may need G at a later visit if healing stalls. If the provider later diagnoses nonunion, K replaces G.

S42.002G code scope: What it covers and what it excludes

S42.002G covers a fracture at an unspecified part of the left clavicle. The clinical documentation does not say whether the break is at the sternal end, the shaft, or the lateral (acromial) end. When the fracture site is documented, a more specific code is available and should be used.

Displacement status

S42.002G also does not specify displacement. When displacement is documented, the coder should look to more specific S42 codes. The sternal end, shaft, and lateral end each have displaced and nondisplaced codes in the S42.01, S42.02, and S42.03 subgroups. Some payers flag the unspecified code when the note clearly states displacement.

Excludes notes

The S42 category carries an Excludes1 note for traumatic amputation of shoulder and upper arm (S48.-). Excludes1 means the two conditions cannot be coded together for the same injury. Periprosthetic fracture around an internal prosthetic shoulder joint (M97.3) is an Excludes2 note. That condition is coded separately when both are present.

S42.002G vs adjacent codes: Choosing the right code

Most coding errors for left clavicle fractures fall into three categories: wrong healing character, wrong laterality, and wrong site specificity. The table below covers the codes most often confused with ICD-10 Code S42.002G.

Use the site-specific codes (S42.012G, S42.022G, S42.032G and their nondisplaced counterparts) whenever the provider documents the fracture location. Defaulting to S42.002G when the note supports a more specific code breaks the coding guidelines and may trigger a payer audit.

Documentation requirements for S42.002G

Supporting a clean claim submission with S42.002G requires four specific elements in the medical record. Missing any one of them gives a payer grounds to downcode or deny the visit. The documentation must establish all of the following:

• Encounter type is a follow-up (not an initial visit): The note must make clear that the patient has already received active treatment for this fracture. Language such as “follow-up for left clavicle fracture” or “continuing management of clavicle fracture” supports subsequent encounter coding.
• Laterality is explicit: The record must state “left” clavicle or “left collarbone.” Bilateral documentation with the left side specifically identified also works. Right-sided or unspecified laterality means a different code applies.
• Healing is delayed: The provider must document that the fracture is healing more slowly than expected. Supporting findings include slower-than-expected callus formation and a persistent fracture line or lucency on follow-up imaging. A provider statement of “delayed union” or “delayed healing” anchors the G character.
• Fracture site is documented (or genuinely unspecified): If the provider documents the exact site (sternal end, shaft, or lateral end), use a more specific code. Use S42.002G only when the site is truly unspecified in the record.

Radiology reports play a central supporting role. A follow-up clavicle X-ray, billed as CPT 73000, is the strongest evidence for the G character when it compares healing with the previous film. Without imaging or an equivalent clinical finding, payers may question whether healing was assessed at all.

Payer requirements for S42.002G claims

Medicare and commercial payers generally cover subsequent fracture management visits when medical necessity is established. The visit must show active monitoring of a fracture that is not healing on schedule. A return to the office alone does not meet that bar.

Medicare-specific considerations

Medicare Local Coverage Determinations (LCDs) for fracture management vary by MAC jurisdiction. Most expect the record to state the clinical reason for each subsequent visit, so the fracture alone is not enough.

Practices billing Medicare for clavicle fracture follow-up should confirm their MAC’s LCD for musculoskeletal fracture management. Follow-up X-ray orders may need S42.002G as the supporting diagnosis.

Common claim denial reasons for S42.002G

Most S42.002G denials trace back to documentation problems or coding logic errors rather than coverage exclusions. Systematic denial management workflows that categorize rejections by root cause catch these patterns quickly. The six most common denial triggers are:

• G used on an initial encounter visit: If the patient is receiving active treatment for this fracture, S42.002A or S42.002B applies. Using G on an initial visit is a coding logic violation and an audit flag.
• Missing laterality in the record: If the provider documentation does not specify left vs. right, the payer cannot confirm the code matches the clinical scenario. The record must explicitly state “left” clavicle.
• Unspecified code when a more specific one is available: Some payers, particularly Medicare Advantage plans, require the most specific code available. If the fracture site is documented, using S42.002G instead of the site-specific code triggers a specificity denial.
• Z47.xx aftercare code used instead of subsequent encounter: ICD-10-CM does not use aftercare Z codes for injuries. The subsequent encounter characters (D, G, K, P) cover fracture follow-up visits. Pairing Z47.89 or a similar code with an S42 code typically generates an edit or outright denial.
• Incorrect D vs. G vs. K selection: G requires documentation of delayed healing. If the note says healing is on track, D applies instead. If the provider diagnoses nonunion, K applies. A G code without delay documented in the record misrepresents the clinical picture and creates a compliance risk.
• Mismatched CPT and ICD-10 pairing: Fracture treatment codes such as 23500 or 23515 describe the initial episode of care. They pair with an initial encounter character. Reporting them with S42.002G generates an edit. See the CPT pairing table below.

Matching the CARC and RARC on each remittance advice against a list of denial codes shows which trigger is active for a given payer. Denial patterns often differ between Medicare fee-for-service and commercial plans.

CPT codes commonly billed with ICD-10 Code S42.002G

S42.002G is a subsequent encounter code. The CPT codes that pair with it are office visit E/M codes, imaging codes, and therapy evaluation codes, not fracture treatment codes.

Understanding medical billing fundamentals for musculoskeletal follow-up means recognizing where each code belongs. CPT 23500 (closed treatment of clavicular fracture, without manipulation) and CPT 23515 (open treatment with internal fixation) pair with S42.002A, not with S42.002G.

Fracture treatment codes such as 23500 and 23515 carry a 90-day global period. Routine follow-up visits by the same provider inside that window are bundled into the treatment fee. Verify CPT and ICD-10 pairings against NCCI edits and the global period before submitting.

Fracture aftercare vs subsequent encounter in ICD-10-CM

Aftercare Z codes are not used for injuries in ICD-10-CM, and that includes fractures. This rule comes from the Official Guidelines, and it trips up coders who learned the ICD-9 approach. Understanding it is central to sound revenue cycle management for orthopedic and musculoskeletal practices.

The subsequent encounter 7th characters (D, G, K, P) replace what aftercare Z codes covered under ICD-9. The decision tree is straightforward:

1. Is the patient receiving active treatment for this fracture? Use 7th character A (closed) or B (open) for the initial encounter.
2. Is the patient returning for follow-up during the healing phase? Use D when healing is routine and G when the provider documents delayed healing.
3. Has the provider diagnosed a failure to unite? Use K (nonunion).
4. Did the fracture heal incorrectly? Use P (malunion).
5. Are you treating late effects after fracture healing is complete? Use S (sequela).
6. Should I use a Z47.xx aftercare code for the fracture? No. ICD-10-CM guidelines rule out aftercare Z codes for injuries.

Visits for sling or cast removal follow the same rule. Guideline I.C.19.a lists cast change or removal and X-rays that check healing status as subsequent encounter care. A sling removal visit for a slow-healing left clavicle fracture is therefore still coded S42.002G.

Is S42.002G still valid?

Yes. S42.002G is a valid, active ICD-10-CM code for FY2027, covering encounters from October 1, 2026 through September 30, 2027. The code and its descriptor have not changed since ICD-10-CM took effect on October 1, 2015. Coders can confirm validity each year using the CDC/NCHS ICD-10-CM web tool or the AAPC Codify ICD-10-CM lookup.

ICD-10-CM codes are revised annually on October 1. For any date of service after September 30, 2027, recheck the applicable fiscal year’s tabular list before billing. CMS publishes the annual update files on its ICD-10 page alongside the full code set.

How Pabau keeps fracture follow-up claims accurate

A delayed-healing case usually means more follow-up visits, more imaging, and more claims for the same fracture. Each one has to carry the right 7th character, or the payer rejects it. Pabau’s claims software for orthopedics keeps that run of claims in one place.

Claims go out electronically through Claim.MD, which connects practices to over 4,000 US payers. Pabau handles 837P electronic submissions, ERA/835 remittance posting, and denial tracking for musculoskeletal claims. Real-time eligibility checks run before each follow-up appointment.

The result is fewer rejected follow-up claims and a clear record of which visits are paid. Billing teams can see denial patterns by CARC code and fix the cause rather than resubmit the same error.

Streamline your fracture claim workflows

Pabau integrates with Claim.MD to handle 837P submissions, real-time eligibility checks, and ERA posting for musculoskeletal claims. See how it works for orthopedic and physical therapy practices.

Book a demo

Conclusion

S42.002G is the right code only when a left clavicle fracture of unspecified site is healing more slowly than expected at a follow-up visit. The healing character is where this code is won or lost. Code D when the provider says healing is on track, G when the note documents a delay, and K once nonunion is diagnosed.

Practices that train providers to state the healing status in every follow-up note will defend this code on audit. That one habit also stops avoidable D, G and K mix-ups before they reach the payer. Book a demo to see how Pabau keeps fracture follow-up claims coded, submitted, and tracked in one system.

Continue your research

Want to understand how electronic claims reach payers? 837 file submission explains the EDI format used for professional claims, including the data elements payers validate for fracture codes.

Frequently asked questions