2026 ICD-10-CM Diagnosis Code S91.042APuncture wound with foreign body, left ankle, initial encounter
S91.042A is a billable ICD-10-CM diagnosis code for puncture wound with foreign body, left ankle, 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 913 through 914, 963 through 965. Coders also document this condition as puncture wound and foreign body of ankle. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Open wounds to limbs, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Puncture wound and foreign body of ankle
- Puncture wound of ankle
- Puncture wound of left ankle region
- Puncture wound of left ankle with foreign body
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Open wound of ankle, foot and toes (S91). 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.
Patient EducationClinical
Ankle Injuries and Disorders
Your ankle bone and the ends of your two lower leg bones make up the ankle joint. Your ligaments, which connect bones to one another, stabilize and support it. Your muscles and tendons move it.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert S91.042A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S91.042AOverview
Is S91.042A (Puncture wound with foreign body, left ankle) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report puncture wound with foreign body, left ankle, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in S91.042A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for puncture wound with foreign body, left ankle, such as an emergency visit or first evaluation.
What MS-DRG does S91.042A group to?
When puncture wound with foreign body, left ankle, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 913, 914, 963, 964, 965, with relative weights from 0.8855 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of S91.042A?
Under the General Equivalence Mappings, puncture wound with foreign body, left ankle, initial encounter converts to ICD-9-CM 891.1 (open wnd knee/leg-compl). 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.
