M84.539K Pathological fracture in neoplastic disease, unspecified ulna and radius, subsequent encounter for fracture with nonunion

Billable ICD-10-CM code, FY2026.

Built from M84.539 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 M84.5 Pathological fracture in neoplastic disease

Code also

• underlying neoplasm

7th character note

• The appropriate 7th character is to be added to each code from subcategory M84.5:

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 M84.539K

Back-references to M84.5

• Type 1 Excludes: M84.4 Pathological fracture, not elsewhere classified ("pathological fracture in neoplastic disease (M84.5-)")

Nearby codes

• M84.534S Pathological fracture in neoplastic disease, left radius, sequela
• M84.539 Pathological fracture in neoplastic disease, unspecified ulna and radius
• M84.539A Pathological fracture in neoplastic disease, unspecified ulna and radius, initial encounter for fracture
• M84.539D Pathological fracture in neoplastic disease, unspecified ulna and radius, subsequent encounter for fracture with routine healing
• M84.539G Pathological fracture in neoplastic disease, unspecified ulna and radius, subsequent encounter for fracture with delayed healing
• M84.539K Pathological fracture in neoplastic disease, unspecified ulna and radius, subsequent encounter for fracture with nonunion (this code)
• M84.539P Pathological fracture in neoplastic disease, unspecified ulna and radius, subsequent encounter for fracture with malunion
• M84.539S Pathological fracture in neoplastic disease, unspecified ulna and radius, sequela
• M84.54 Pathological fracture in neoplastic disease, hand
• M84.541 Pathological fracture in neoplastic disease, right hand
• M84.541A Pathological fracture in neoplastic disease, right hand, initial encounter for fracture