M84.339K Stress fracture, unspecified ulna and radius, subsequent encounter for fracture with nonunion

Billable ICD-10-CM code, FY2026.

Built from M84.339 with 7th character K (subsequent encounter for fracture with nonunion).

Applies from M84 Disorder of continuity of bone

Excludes2 (not included here)

• traumatic fracture of bone-see fracture, by site

Applies from M84.3 Stress fracture

Applicable to

• Fatigue fracture
• March fracture
• Stress fracture NOS
• Stress reaction

Excludes1 (never code together)

• pathological fracture NOS (M84.4.-)
• pathological fracture due to osteoporosis (M80.-)
• traumatic fracture (S12.-, S22.-, S32.-, S42.-, S52.-, S62.-, S72.-, S82.-, S92.-)

Excludes2 (not included here)

• personal history of (healed) stress (fatigue) fracture (Z87.312)
• stress fracture of vertebra (M48.4-)

Use additional code

• external cause code(s) to identify the cause of the stress fracture

7th character note

• The appropriate 7th character is to be added to each code from subcategory M84.3:

7th character required

• A — initial encounter for fracture
• D — subsequent encounter for fracture with routine healing
• G — subsequent encounter for fracture with delayed healing
• K — subsequent encounter for fracture with nonunion
• P — subsequent encounter for fracture with malunion
• S — sequela

Medicare Code Edits (MCE v43.1 (April 2026))

• Unspecified code (laterality): Unspecified codes for which a more specific code identifying laterality (right, left, bilateral) exists within the same code family.

Code annotations containing back-references to M84.339K

Back-references to M84.3

• Type 1 Excludes: M84.4 Pathological fracture, not elsewhere classified ("stress fracture (M84.3-)")

Nearby codes

• M84.334S Stress fracture, left radius, sequela
• M84.339 Stress fracture, unspecified ulna and radius
• M84.339A Stress fracture, unspecified ulna and radius, initial encounter for fracture
• M84.339D Stress fracture, unspecified ulna and radius, subsequent encounter for fracture with routine healing
• M84.339G Stress fracture, unspecified ulna and radius, subsequent encounter for fracture with delayed healing
• M84.339K Stress fracture, unspecified ulna and radius, subsequent encounter for fracture with nonunion (this code)
• M84.339P Stress fracture, unspecified ulna and radius, subsequent encounter for fracture with malunion
• M84.339S Stress fracture, unspecified ulna and radius, sequela
• M84.34 Stress fracture, hand and fingers
• M84.341 Stress fracture, right hand
• M84.341A Stress fracture, right hand, initial encounter for fracture