2027 ICD-10-CM Diagnosis Code M84.339AStress fracture, unspecified ulna and radius, initial encounter for fracture
M84.339A is a billable ICD-10-CM diagnosis code for stress fracture, unspecified ulna and radius, initial encounter for fracture. The 7th character A means initial encounter for fracture, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 542 through 544. Coders also document this condition as stress fracture of radius. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Stress fracture, initial encounter.
Code Identity
Code Classification
Quality Payment Program MeasuresBilling
Medicare quality measures that can apply when M84.339A is part of the patient record.
Communication with the Physician or Other Clinician Managing On-Going Care Post-Fracture for Men and Women Aged 50 Years and Older
High Priority: YES
Measure Type: Process
Submission Methods: Claims, Registry
Description: Percentage of patients aged 50 years and older treated for a fracture with documentation of communication, between the physician treating the fracture and the physician or other clinician managing the patient’s on-going care, that a fracture occurred and that the patient was or should be considered for osteoporosis treatment or testing. This measure is submitted by the physician who treats the fracture and who therefore is held accountable for the communication.
Osteoporosis Management in Women Who Had a Fracture
High Priority: NO
Measure Type: Process
Submission Methods: Claims, Registry
Description: The percentage of women 50-85 years of age who suffered a fracture and who had either a bone mineral density (BMD) test or prescription for a drug to treat osteoporosis in the 180 days after the fracture.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Stress fracture of radius
- Stress fracture of ulna
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to M84.339A: its own notes plus those printed at M84.3, M84, and Chapter 13. A note printed at a category, block or chapter applies to every code under it.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
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.
- traumatic fracture of bone-see fracture, by site
- 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)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- external cause code(s) to identify the cause of the stress fracture
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
7th Character
Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.
- The appropriate 7th character is to be added to each code from subcategory M84.3:
- Ainitial encounter for fracture this code
- Dsubsequent encounter for fracture with routine healing
- Gsubsequent encounter for fracture with delayed healing
- Ksubsequent encounter for fracture with nonunion
- Psubsequent encounter for fracture with malunion
- Ssequela
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name M84.339A, its category, or a range that includes it.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Fractures, Stress
fractures due to the strain caused by repetitive exercise. they are thought to arise from a combination of muscle fatigue and bone failure, and occur in situations where bone remodeling predominates over repair. the most common sites of stress fractures are the metatarsus; fibula; tibia; and femoral neck.
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.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M84.339A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M84.339AOverview
Is M84.339A (Stress fracture, unspecified ulna and radius) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report stress fracture, unspecified ulna and radius, initial encounter for fracture on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character A in M84.339A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for stress fracture, unspecified ulna and radius, such as an emergency visit or first evaluation. In this category the CMS Tabular List defines A as "initial encounter for fracture".
What MS-DRG does M84.339A group to?
When stress fracture, unspecified ulna and radius, initial encounter for fracture is the principal diagnosis on an inpatient stay, it groups to MS-DRG 543, 544, 542, with relative weights from 0.7404 to 1.7208 depending on complications. Higher weights mean higher Medicare reimbursement.
Can M84.339A be reported with a code from M84.4?
Not as a rule. The Excludes1 note at M84.3, which applies to M84.339A, lists "pathological fracture NOS (M84.4.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
Does M84.339A need an additional code?
When the condition applies, yes. The Use Additional Code note at M84.3, which applies to M84.339A, reads: external cause code(s) to identify the cause of the stress fracture. The additional code is reported after M84.339A.
