2026 ICD-10-CM Diagnosis Code M66.269Spontaneous rupture of extensor tendons, unspecified lower leg
ICD-10-CM Codes›M00–M99›M65-M67›M66
- Billable — Valid for Submission
- Not Chronic
M66.269 is a billable ICD-10-CM diagnosis code for spontaneous rupture of extensor tendons, unspecified lower leg. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 557 through 558. Coders also document this condition as nontraumatic rupture of extensor tendon of lower leg. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Tendon and synovial disorders.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Nontraumatic rupture of extensor tendon of lower leg
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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 M66.269 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M66.269Overview
Is M66.269 (Spontaneous rupture of extensor tendons, lower leg) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report spontaneous rupture of extensor tendons, unspecified lower leg on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does M66.269 group to?
When spontaneous rupture of extensor tendons, unspecified lower leg is the principal diagnosis on an inpatient stay, it groups to MS-DRG 557, 558, with relative weights from 0.8932 to 1.4869 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of M66.269?
Under the General Equivalence Mappings, spontaneous rupture of extensor tendons, unspecified lower leg converts to ICD-9-CM 727.66 (rupture patellar tendon). 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.
