M89.779 – Major osseous defect, unspecified ankle and foot

ICD-10-CM 2027 diagnosis code · Other osteopathies

Billable code

ICD-10-CM code M89.779

Code: M89.779 (claims format: M89779)
Description: Major osseous defect, unspecified ankle and foot
Billable: Yes – valid for HIPAA-covered transactions
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 13. Diseases of the musculoskeletal system and connective tissue (M00-M99)
Block: M86-M90 Other osteopathies
Parent codes: M89 › M89.7 › M89.77

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

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-)

M89.77 – Major osseous defect, ankle and foot

Applicable to:

Major osseous defect of metatarsus, tarsus, toes

Block M86-M90

Excludes1 (not coded here):

postprocedural osteopathies (M96.-)

Related codes in M89.77

Frequently asked questions

What is ICD-10 code M89.779?

M89.779 is the ICD-10-CM code for major osseous defect, unspecified ankle and foot, in the block M86-M90 (Other osteopathies).

Is M89.779 a billable code?

Yes. M89.779 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.

What category does M89.779 belong to?

It belongs to category M89 – Other disorders of bone.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.