M65.879 — Other synovitis and tenosynovitis, unspecified ankle and foot
Is M65.879 billable?
Yes, but M65.879 is an unspecified code. M65.879 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, M65.879 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 M65.879 — the more specific alternatives are listed below.
M65.879 at a glance
| Code | M65.879 |
|---|---|
| Description | Other synovitis and tenosynovitis, unspecified ankle and foot |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does M65.879 group to?
M65.879 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 M65.879 listed in the Alphabetic Index?
The Alphabetic Index lists these routes under M65.87, the nearest indexed parent of M65.879. Use them to find the family, then select the specific code.
- Tenosynovitis › specified type NEC › ankle
- Tenosynovitis › specified type NEC › foot
Excludes1 — never code together — inherited from M65
The conditions below can never be reported together with M65.879 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Excludes2 — not included here — inherited from Chapter 13
The conditions below are not part of M65.879, but a patient may have both at the same time. When documentation supports it, M65.879 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)
How long has M65.879 existed?
M65.879 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.