2027 ICD-10-CM Diagnosis Code S86.399SOther injury of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, unspecified leg, sequela
S86.399S is a billable ICD-10-CM diagnosis code for other injury of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, unspecified leg, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 913 through 914. The code is exempt from POA reporting. Coders also document this condition as subluxation of peroneal tendon. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Injury, sequela.
Code Identity
Code Classification
Present on Admission (POA)Billing
S86.399S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Injuries to the knee and lower leg (S80-S89).
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Subluxation of peroneal tendon
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Injury of muscle, fascia and tendon at lower leg level (S86). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027, published by CMS and the National Center for Health Statistics.
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to S86.399S: its own notes plus those printed at S86, block S80-S89, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify any retained foreign body, if applicable (Z18.-)
Code Also
A second code may be needed to fully describe the condition; the note gives no sequencing direction.
Notes
General instructions on how these codes are used.
- Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
- The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.
7th Character
Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.
- The appropriate 7th character is to be added to each code from category S86
- Ainitial encounter
- Dsubsequent encounter
- Ssequela this code
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name S86.399S, its category, or a range that includes it.
Excludes2 2
These codes carry an Excludes2 note naming S86.399S: its condition is not part of those codes, and both may be reported when the patient has both.
- S76 Injury of muscle, fascia and tendon at hip and thigh levelinjury of muscle, fascia and tendon at lower leg level (S86) names S86, which includes this code
- S83 Dislocation and sprain of joints and ligaments of kneestrain of muscle, fascia and tendon of lower leg (S86.-) names S86.-, which includes this code
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Leg Injuries and Disorders
Your legs are made up of bones, blood vessels, muscles, and other connective tissue. They are important for motion and standing. Playing sports, running, falling, or having an accident can damage your legs. Common leg injuries include sprains and strains, joint dislocations, and fractures (broken bones).
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert S86.399S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S86.399SOverview
Is S86.399S a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other injury of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, unspecified leg, sequela on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character S in S86.399S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the other injury of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, unspecified leg itself has resolved, not the original event.
What MS-DRG does S86.399S group to?
When other injury of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, unspecified leg, sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 914, 913, with relative weights from 0.9281 to 1.5448 depending on complications. Higher weights mean higher Medicare reimbursement.
Is S86.399S exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for other injury of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, unspecified leg, sequela on inpatient claims. The code appears in the Injuries to the knee and lower leg (S80-S89) range of the CMS exempt list.
What is the ICD-9 equivalent of S86.399S?
Under the General Equivalence Mappings, other injury of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, unspecified leg, sequela converts to ICD-9-CM 908.9 (late effect injury NOS). The mapping is approximate, so confirm the match fits the documentation.
