M84.421K Pathological fracture, right humerus, subsequent encounter for fracture with nonunion

Billable ICD-10-CM code, FY2026.

Built from M84.421 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 M84.4 Pathological fracture, not elsewhere classified

Applicable to

• Chronic fracture
• Pathological fracture NOS

Excludes1 (never code together)

• collapsed vertebra NEC (M48.5)
• pathological fracture in neoplastic disease (M84.5-)
• pathological fracture in osteoporosis (M80.-)
• pathological fracture in other disease (M84.6-)
• stress fracture (M84.3-)
• traumatic fracture (S12.-, S22.-, S32.-, S42.-, S52.-, S62.-, S72.-, S82.-, S92.-)

Excludes2 (not included here)

• personal history of (healed) pathological fracture (Z87.311)

7th character note

• The appropriate 7th character is to be added to each code from subcategory M84.4:

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

Code annotations containing back-references to M84.421K

Back-references to M84.4

• Type 1 Excludes: M48.4 Fatigue fracture of vertebra ("pathological fracture NOS (M84.4-)")
• Type 1 Excludes: M48.5 Collapsed vertebra, not elsewhere classified ("pathological fracture NOS (M84.4-)")
• Type 1 Excludes: M80 Osteoporosis with current pathological fracture ("pathological fracture NOS (M84.4)")
• Type 1 Excludes: M84.3 Stress fracture ("pathological fracture NOS (M84.4.-)")

Nearby codes

• M84.42 Pathological fracture, humerus
• M84.421 Pathological fracture, right humerus
• M84.421A Pathological fracture, right humerus, initial encounter for fracture
• M84.421D Pathological fracture, right humerus, subsequent encounter for fracture with routine healing
• M84.421G Pathological fracture, right humerus, subsequent encounter for fracture with delayed healing
• M84.421K Pathological fracture, right humerus, subsequent encounter for fracture with nonunion (this code)
• M84.421P Pathological fracture, right humerus, subsequent encounter for fracture with malunion
• M84.421S Pathological fracture, right humerus, sequela
• M84.422 Pathological fracture, left humerus
• M84.422A Pathological fracture, left humerus, initial encounter for fracture
• M84.422D Pathological fracture, left humerus, subsequent encounter for fracture with routine healing