2026 ICD-10-CM Diagnosis Code S81.809AUnspecified open wound, unspecified lower leg, initial encounter

ICD-10-CM S81.809A

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

S81.809A is a billable ICD-10-CM diagnosis code for unspecified open wound, unspecified lower leg, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 604 through 605, 963 through 965. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Open wounds to limbs, initial encounter.

Code Identity

ICD-10-CM Code

S81.809A

Billable Status

Yes — Valid for Submission

Code Describes

Unspecified open wound, unspecified lower leg, initial encounter

Short Description

Unspecified open wound, unspecified lower leg, init encntr

Parent Code

S81.809

Unspecified open wound, unspecified lower leg

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes

SectionS80-S89Injuries to the knee and lower leg

CategoryS81Open wound of knee and lower leg

This CodeS81.809AUnspecified open wound, unspecified lower leg, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

Filter synonyms:

Fracture of head of fibula
Fracture of neck of fibula
Fracture of shaft of tibia and fibula
Fracture of tibial spine
Fracture of upper end of lower leg
Glass in lower leg
Glass in shin
Injury of anterior tibial artery
Injury of cutaneous sensory nerve of lower limb
Injury of popliteal artery
Injury of popliteal vein
Injury of tibial nerve
Multiple open wounds of lower leg
Multiple open wounds of lower limb
Open bimalleolar fracture
Open division, superior tibiofibular ligament
Open fracture ankle, bimalleolar, high fibular fracture
Open fracture ankle, bimalleolar, low fibular fracture
Open fracture ankle, lateral malleolus, high
Open fracture ankle, lateral malleolus, low
Open fracture ankle, trimalleolar, high fibular fracture
Open fracture ankle, trimalleolar, low fibular fracture
Open fracture distal tibia
Open fracture distal tibia, extra-articular
Open fracture distal tibia, intra-articular
Open fracture fibula, head
Open fracture fibula, neck
Open fracture intercondylar spine of tibia
Open fracture of distal fibula
Open fracture of distal tibia and distal fibula
Open fracture of fibula
Open fracture of lateral malleolus
Open fracture of lower leg
Open fracture of medial malleolus
Open fracture of shaft of fibula
Open fracture of shaft of tibia
Open fracture of tibia
Open fracture of tibia AND fibula
Open fracture of tibia and fibula, shaft
Open fracture of tibial condyle
Open fracture of tibial plateau
Open fracture of tibial tuberosity
Open fracture of upper end of fibula
Open fracture of upper end of lower leg
Open fracture of upper end of tibia
Open fracture proximal tibia, bicondylar
Open fracture proximal tibia, lateral condyle
Open fracture proximal tibia, medial condyle
Open injury cutaneous sensory nerve of lower limb
Open injury posterior tibial nerve
Open injury, anterior tibial artery
Open injury, popliteal artery
Open injury, popliteal vein
Open pilon fracture
Open trimalleolar fracture
Open wound of lower leg
Pilon fracture
Trimalleolar fracture

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Open wound of knee and lower leg (S81). 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 INJ012

Open wounds to limbs, initial encounter

Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Wounds and Injuries

An injury is damage to your body. It is a general term that refers to harm caused by accidents, falls, hits, weapons, and more. In the U.S., millions of people injure themselves every year. These injuries range from minor to life-threatening.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert S81.809A to ICD-9-CMHistory

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

ICD-9-CM

891.0 Open wnd knee/leg/ankle

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 S81.809AOverview

Is S81.809A (Unspecified open wound, unspecified lower leg) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified open wound, unspecified lower leg, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in S81.809A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for unspecified open wound, unspecified lower leg, such as an emergency visit or first evaluation.

What MS-DRG does S81.809A group to?

When unspecified open wound, unspecified lower leg, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 604, 605, 963, 964, 965, with relative weights from 0.9160 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of S81.809A?

Under the General Equivalence Mappings, unspecified open wound, unspecified lower leg, initial encounter converts to ICD-9-CM 891.0 (open wnd knee/leg/ankle). 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.

Indicator	Meaning	CMS pays CC/MCC DRG
Y	Diagnosis was present at the time of inpatient admission	Yes
N	Diagnosis was not present at the time of admission	No
U	Documentation is insufficient to determine	No
W	Clinically undetermined	Yes
1	Unreported, exempt from POA reporting	No