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ICD-10-CM 2027 diagnosis code

M89.79Major osseous defect, multiple sites

✓ Billable / specific

M89.79 is a valid, billable ICD-10-CM code for major osseous defect, multiple sites. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About M89.79

M89.79 is the ICD-10-CM diagnosis code for major osseous defect, multiple sites. It belongs to category M89 (other disorders of bone), block M86-M90 (other osteopathies) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within M89.7 (major osseous defect), M89.79 is specifically for major osseous defect, multiple sites. Related codes cover unspecified site (M89.70), shoulder region (M89.71), humerus (M89.72), forearm (M89.73), hand (M89.74), pelvic region and thigh (M89.75), lower leg (M89.76), ankle and foot (M89.77) and 1 more.

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 553 (Bone Diseases and Arthropathies with MCC, relative weight 1.2494) and DRG 554 (Bone Diseases and Arthropathies without MCC, relative weight 0.8331), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 731.3 (major osseous defects).

Notes that apply from higher levels

Instructions written at a parent level also apply to M89.79.

› 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-)

Broader instructions also apply from M86-M90 Other osteopathies and Chapter 13: Diseases of the musculoskeletal system and connective tissue.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to M89.79.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

MDC 08 · Diseases and Disorders of the Musculoskeletal System and Connective Tissue

ICD-9-CM equivalent

Converter →
  • 731.3Major osseous defectsapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about M89.79

Is M89.79 billable?

Yes. M89.79 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can M89.79 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict M89.79 as a principal diagnosis.

Is M89.79 a CC or MCC?

No. M89.79 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does M89.79 group to?

M89.79 is used in the MS-DRG v44.0 logic for MS-DRG 553 (Bone Diseases and Arthropathies with MCC) and MS-DRG 554 (Bone Diseases and Arthropathies without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for M89.79?

The CMS General Equivalence Mappings map M89.79 to ICD-9-CM 731.3.