2026 ICD-10-CM Diagnosis Code S86.309SUnspecified injury of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, unspecified leg, sequela

ICD-10-CM Codes›S00–T88›S80-S89›S86

ICD-10-CM S86.309S
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S86.309S is a billable ICD-10-CM diagnosis code for unspecified 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 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 913 through 914. The code is exempt from POA reporting. Coders also document this condition as injury of multiple muscles and tendons at lower leg level. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Injury, sequela.

Code Identity

ICD-10-CM Code
S86.309S
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified injury of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, unspecified leg, sequela
Short Description
Unsp inj musc/tend peroneal grp at low leg lev,unsp leg,sqla
Parent Code
S86.309
Unspecified injury of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, unspecified leg

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS80-S89Injuries to the knee and lower leg
CategoryS86Injury of muscle, fascia and tendon at lower leg level
This CodeS86.309SUnspecified injury of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, unspecified leg, sequela

Present on Admission (POA)Billing

S86.309S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Injury of multiple muscles and tendons at lower leg level
  • Injury of muscle of peroneal muscle group at lower leg level

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 2026, published by CMS and the National Center for Health Statistics.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ073
Injury, sequela
Default principal diagnosis: inpatient Yes · outpatient Yes

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 S86.309S to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
908.9 Late effect injury NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About S86.309SOverview

Is S86.309S a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified 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, 2025 through September 30, 2026.

What does the 7th character S in S86.309S mean?

The final character S makes this a sequela code: it reports a lingering problem that remains after the unspecified 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 S86.309S group to?

When unspecified 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 913, 914, with relative weights from 0.8855 to 1.6346 depending on complications. Higher weights mean higher Medicare reimbursement.

Is S86.309S 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 unspecified injury of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, unspecified leg, sequela on inpatient claims.

What is the ICD-9 equivalent of S86.309S?

Under the General Equivalence Mappings, unspecified 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.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.