M89.779 Major osseous defect, unspecified ankle and foot

Billable ICD-10-CM code, FY2026.

Applies from M89.7 Major osseous defect

Code first

• underlying disease, if known, such as:
• aseptic necrosis of bone (M87.-)
• malignant neoplasm of bone (C40.-)
• osteolysis (M89.5-)
• osteomyelitis (M86.-)
• osteonecrosis (M87.-)
• osteoporosis (M80.-, M81.-)
• periprosthetic osteolysis (T84.05-)

Applies from M89.77 Major osseous defect, ankle and foot

Applicable to

• Major osseous defect of metatarsus, tarsus, toes

MS-DRG index

Defines the logic of DRG(s) 553-554 in MDC 08.

Approximate ICD-9-CM (GEMs)

• 731.3 Major osseous defects (approximate)

Code annotations containing back-references to M89.779

Back-references to M89.7

• Use Additional: C40 Malignant neoplasm of bone and articular cartilage of limbs ("code to identify major osseous defect, if applicable (M89.7-)")
• Use Additional: M80 Osteoporosis with current pathological fracture ("code to identify major osseous defect, if applicable (M89.7-)")
• Use Additional: M81 Osteoporosis without current pathological fracture ("major osseous defect, if applicable (M89.7-)")
• Use Additional: M86 Osteomyelitis ("code to identify major osseous defect, if applicable (M89.7-)")
• Use Additional: M87 Osteonecrosis ("code to identify major osseous defect, if applicable (M89.7-)")
• Use Additional: M89.5 Osteolysis ("code to identify major osseous defect, if applicable (M89.7-)")
• Use Additional: T84.05 Periprosthetic osteolysis of internal prosthetic joint ("code to identify major osseous defect, if applicable (M89.7-)")

Nearby codes

• M89.762 Major osseous defect, left lower leg
• M89.769 Major osseous defect, unspecified lower leg
• M89.77 Major osseous defect, ankle and foot
• M89.771 Major osseous defect, right ankle and foot
• M89.772 Major osseous defect, left ankle and foot
• M89.779 Major osseous defect, unspecified ankle and foot (this code)
• M89.78 Major osseous defect, other site
• M89.79 Major osseous defect, multiple sites
• M89.8 Other specified disorders of bone
• M89.8X Other specified disorders of bone
• M89.8X0 Other specified disorders of bone, multiple sites