2026 ICD-10-CM Diagnosis Code S81Open wound of knee and lower leg
S81 is a non-billable ICD-10-CM category code for open wound of knee and lower leg, so it cannot be submitted on claims. Use a more specific code from this category instead, such as S81.001A, S81.001D, S81.001S, and S81.002A.
Code Identity
Code Classification
Specific Coding for Open wound of knee and lower legOverview
Non-specific codes like S81 require more characters. Use one of these billable codes instead:
S81.0 for Open wound of knee
S81.00 for Unspecified open wound of knee
S81.01 for Laceration without foreign body of knee
S81.02 for Laceration with foreign body of knee
S81.03 for Puncture wound without foreign body of knee
S81.04 for Puncture wound with foreign body of knee
S81.05 for Open bite of knee
S81.8 for Open wound of lower leg
S81.80 for Unspecified open wound of lower leg
S81.81 for Laceration without foreign body of lower leg
S81.82 for Laceration with foreign body of lower leg
S81.83 for Puncture wound without foreign body of lower leg
S81.84 for Puncture wound with foreign body of lower leg
S81.85 for Open bite of lower leg
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.
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Code Also
- any associated wound infection
Type 1 Excludes
Type 2 Excludes
- open wound of ankle and foot S91
7th Character Note
- The appropriate 7th character is to be added to each code from category S81
7th Character
- A - initial encounter
- D - subsequent encounter
- S - sequela
A "code also" note instructs that two codes may be required to fully describe a condition, but this note does not provide sequencing direction.
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
Certain ICD-10-CM categories have applicable 7th characters. The applicable 7th character is required for all codes within the category, or as the notes in the Tabular List instruct. The 7th character must always be the 7th character in the data field. If a code that requires a 7th character is not 6 characters, a placeholder X must be used to fill in the empty characters.
Indicates that a seventh character is to be assigned to codes in a subcategory.
Patient EducationClinical
Knee Injuries and Disorders
Your knee joint is made up of bone, cartilage, ligaments and fluid. Muscles and tendons help the knee joint move. When any of these structures is hurt or diseased, you have knee problems. Knee problems can cause pain and difficulty walking.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Code HistoryHistory
Questions About S81Overview
Is S81 (Open wound of knee and lower leg) a billable code?
No. This is a category header that groups the codes for open wound of knee and lower leg, and headers cannot be submitted on claims. Claims for open wound of knee and lower leg need a more specific code from this category, such as S81.001A, S81.001D, and S81.001S.
