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ICD-10-CM 2027 diagnosis code

M77.9Enthesopathy, unspecified

✓ Billable / specific

M77.9 is a valid, billable ICD-10-CM code for enthesopathy, unspecified. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Enthesopathy.

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 M77.9

M77.9 is the ICD-10-CM diagnosis code for enthesopathy, unspecified. It belongs to category M77 (other enthesopathies), block M70-M79 (other soft tissue disorders) 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 M77, choose M77.9 (Enthesopathy, unspecified) only when documentation doesn't support a more specific option: medial epicondylitis (M77.0), lateral epicondylitis (M77.1), Periarthritis of wrist (M77.2), Calcaneal spur (M77.3), Metatarsalgia (M77.4), other enthesopathy of foot and ankle (M77.5) and not elsewhere classified (M77.8).

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 557 (Tendonitis, Myositis and Bursitis with MCC, relative weight 1.489) and DRG 558 (Tendonitis, Myositis and Bursitis without MCC, relative weight 0.8875), 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 726.90 (enthesopathy of unspecified site).

Coding notes

Applicable toConditions and synonyms classified to this code
  • Bone spur NOS
  • Capsulitis NOS
  • Periarthritis NOS
  • Tendinitis NOS

Notes that apply from higher levels

Instructions written at a parent level also apply to M77.9.

› From M77 Other enthesopathies
Excludes1
Excludes2
  • bursitis due to use, overuse and pressure (M70.-)
  • osteophyte (M25.7)
  • spinal enthesopathy (M46.0-)

Broader instructions also apply from 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 M77.9.

Codes whose notes reference M77.9

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 →
  • 726.90Enthesopathy of unspecified siteexact

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 M77.9

Is M77.9 billable?

Yes. M77.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can M77.9 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict M77.9 as a principal diagnosis.

Is M77.9 a CC or MCC?

No. M77.9 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does M77.9 group to?

M77.9 is used in the MS-DRG v44.0 logic for MS-DRG 557 (Tendonitis, Myositis and Bursitis with MCC) and MS-DRG 558 (Tendonitis, Myositis and Bursitis 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 M77.9?

The CMS General Equivalence Mappings map M77.9 to ICD-9-CM 726.90.