M77.9 — Enthesopathy, unspecified
Is M77.9 billable?
Yes, but M77.9 is an unspecified code. M77.9 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, M77.9 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting M77.9 — the more specific alternatives are listed below.
M77.9 at a glance
| Code | M77.9 |
|---|---|
| Description | Enthesopathy, unspecified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does M77.9 group to?
M77.9 sits in MDC 08 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 557Tendonitis, Myositis and Bursitis with MCCmedical
- 558Tendonitis, Myositis and Bursitis without MCCmedical
How is M77.9 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to M77.9. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Enthesopathy (peripheral)
Inclusion terms
Alternative wording in documentation that is classified to M77.9.
- Bone spur NOS
- Capsulitis NOS
- Periarthritis NOS
- Tendinitis NOS
Excludes1 — never code together — inherited from M77
The conditions below can never be reported together with M77.9 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- bursitis NOS (M71.9-)
Excludes2 — not included here — inherited from Chapter 13
The conditions below are not part of M77.9, but a patient may have both at the same time. When documentation supports it, M77.9 and the excluded code may both be reported.
- arthropathic psoriasis (L40.5-)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- compartment syndrome (traumatic) (T79.A-)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Excludes2 — not included here — inherited from M77
The conditions below are not part of M77.9, but a patient may have both at the same time. When documentation supports it, M77.9 and the excluded code may both be reported.
How long has M77.9 existed?
M77.9 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.