2026 ICD-10-CM Diagnosis Code M84.639SPathological fracture in other disease, unspecified ulna and radius, sequela
M84.639S is a billable ICD-10-CM diagnosis code for pathological fracture in other disease, unspecified ulna and radius, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 559 through 561. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Pathological, stress and atypical fractures, sequela.
Code Identity
Code Classification
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Arm Injuries and Disorders
Of the 206 bones in your body, three of them are in your arm: the humerus, radius, and ulna. Your arms are also made up of muscles, joints, tendons, and other connective tissue. Injuries to any of these parts of the arm can occur during sports, a fall, or an accident.
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Convert M84.639S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M84.639SOverview
Is M84.639S a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report pathological fracture in other disease, unspecified ulna and radius, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in M84.639S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the pathological fracture in other disease, unspecified ulna and radius itself has resolved, not the original event.
What MS-DRG does M84.639S group to?
When pathological fracture in other disease, unspecified ulna and radius, sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 559, 560, 561, with relative weights from 0.8039 to 1.8649 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of M84.639S?
Under the General Equivalence Mappings, pathological fracture in other disease, unspecified ulna and radius, sequela converts to ICD-9-CM 905.2 (late effect arm fx). 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.
