2027 ICD-10-CM Diagnosis Code M25.173Fistula, unspecified ankle
ICD-10-CM Codes›M00–M99›M20-M25›M25
- Billable — Valid for Submission
- Not Chronic
M25.173 is a billable ICD-10-CM diagnosis code for fistula, unspecified ankle. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 555 through 556. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified joint disorders.
Code Identity
Code Classification
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to M25.173: its own notes plus those printed at M25, block M00-M25, block M20-M25, and Chapter 13. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- Disorders affecting predominantly peripheral (limb) joints
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.
- arthropathic psoriasis (L40.5-)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- compartment syndrome (traumatic) (T79.A-)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Notes
General instructions on how these codes are used.
- Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Fistula
abnormal communication most commonly seen between two internal organs, or between an internal organ and the surface of the body.
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 M25.173 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M25.173Overview
What is the ICD-10 code for fistula, unspecified ankle?
The ICD-10-CM code for fistula, unspecified ankle is M25.173 (sometimes written as M25173). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is M25.173 (Fistula, ankle and foot) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report fistula, unspecified ankle on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does M25.173 group to?
When fistula, unspecified ankle is the principal diagnosis on an inpatient stay, it groups to MS-DRG 555, 556, with relative weights from 0.8210 to 1.2908 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of M25.173?
Under the General Equivalence Mappings, fistula, unspecified ankle converts to ICD-9-CM 719.87 (joint dis NEC-ankle). The mapping is approximate, so confirm the match fits the documentation.
