S52.399K — Other fracture of shaft of radius, unspecified arm, subsequent encounter for closed fracture with nonunion
Is S52.399K billable?
Yes, but S52.399K will trip a Medicare edit. S52.399K is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, CMS lists S52.399K under Medicare Code Editor edit 20, “Unspecified code” — meaning a code specifying laterality (right, left or bilateral) exists in the same family. On an inpatient claim this triggers the edit, because CMS holds that there are very limited circumstances in which laterality cannot be documented.
S52.399K at a glance
| Code | S52.399K |
|---|---|
| Description | Other fracture of shaft of radius, unspecified arm, subsequent encounter for closed fracture with nonunion |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
| 7th character "K" | subsequent encounter for closed fracture with nonunion |
What does the 7th character "K" mean in S52.399K?
In S52.399K, the 7th character K means subsequent encounter for closed fracture with nonunion. The 7th character is required for S52.399K to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
- Ainitial encounter for closed fractureS52.399A
- Binitial encounter for open fracture type I or IIS52.399B
- Cinitial encounter for open fracture type IIIA, IIIB, or IIICS52.399C
- Dsubsequent encounter for closed fracture with routine healingS52.399D
- Esubsequent encounter for open fracture type I or II with routine healingS52.399E
- Fsubsequent encounter for open fracture type IIIA, IIIB, or IIIC with routine healingS52.399F
- Gsubsequent encounter for closed fracture with delayed healingS52.399G
- Hsubsequent encounter for open fracture type I or II with delayed healingS52.399H
- Jsubsequent encounter for open fracture type IIIA, IIIB, or IIIC with delayed healingS52.399J
- Ksubsequent encounter for closed fracture with nonunionS52.399K
- Msubsequent encounter for open fracture type I or II with nonunionS52.399M
- Nsubsequent encounter for open fracture type IIIA, IIIB, or IIIC with nonunionS52.399N
- Psubsequent encounter for closed fracture with malunionS52.399P
- Qsubsequent encounter for open fracture type I or II with malunionS52.399Q
- Rsubsequent encounter for open fracture type IIIA, IIIB, or IIIC with malunionS52.399R
- SsequelaS52.399S
What Medicare edits apply to S52.399K?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name S52.399K directly.
A code specifying laterality (right, left or bilateral) exists in the same family. CMS holds that there are very limited circumstances in which laterality cannot be documented.
Which MS-DRGs does S52.399K group to?
S52.399K sits in MDC 08 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 564Other Musculoskeletal System and Connective Tissue Diagnoses with MCCmedical
- 565Other Musculoskeletal System and Connective Tissue Diagnoses with CCmedical
- 566Other Musculoskeletal System and Connective Tissue Diagnoses without CC/MCCmedical
As a secondary diagnosis, S52.399K is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is S52.399K listed in the Alphabetic Index?
The Alphabetic Index lists these routes under S52.39, the nearest indexed parent of S52.399K. Use them to find the family, then select the specific code.
- Fracture, traumatic › radius › shaft › specified NEC (abduction) (adduction) (separation)
Excludes1 — never code together — inherited from S52
The conditions below can never be reported together with S52.399K on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- traumatic amputation of forearm (S58.-)
Use additional code — inherited from Chapter 19
Report an additional code alongside S52.399K to fully describe the condition. S52.399K is sequenced first.
- code to identify any retained foreign body, if applicable (Z18.-)
Excludes2 — not included here — inherited from Chapter 19
The conditions below are not part of S52.399K, but a patient may have both at the same time. When documentation supports it, S52.399K and the excluded code may both be reported.
Excludes2 — not included here — inherited from S50-S59
The conditions below are not part of S52.399K, but a patient may have both at the same time. When documentation supports it, S52.399K and the excluded code may both be reported.
Excludes2 — not included here — inherited from S52
The conditions below are not part of S52.399K, but a patient may have both at the same time. When documentation supports it, S52.399K and the excluded code may both be reported.
How long has S52.399K existed?
S52.399K has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.