M86.659 — Other chronic osteomyelitis, unspecified thigh
Is M86.659 billable?
Yes, but M86.659 will trip a Medicare edit. M86.659 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, CMS lists M86.659 under Medicare Code Editor edit 20, “Unspecified code” — meaning a code specifying laterality (right, left or bilateral) exists in the same family. On an inpatient claim this triggers the edit, because CMS holds that there are very limited circumstances in which laterality cannot be documented.
More specific alternatives
M86.659 at a glance
| Code | M86.659 |
|---|---|
| Description | Other chronic osteomyelitis, unspecified thigh |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
What Medicare edits apply to M86.659?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name M86.659 directly.
A code specifying laterality (right, left or bilateral) exists in the same family. CMS holds that there are very limited circumstances in which laterality cannot be documented.
Which MS-DRGs does M86.659 group to?
M86.659 sits in MDC 08 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 539Osteomyelitis with MCCmedical
- 540Osteomyelitis with CCmedical
- 541Osteomyelitis without CC/MCCmedical
As a secondary diagnosis, M86.659 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is M86.659 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to M86.659. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Osteomyelitis › chronic › ilium (general) (infective) (localized) (neonatal) (purulent) (septic) (staphylococcal) (streptococcal) (suppurative) (with periostitis)
- Osteomyelitis › chronic › ischium (general) (infective) (localized) (neonatal) (purulent) (septic) (staphylococcal) (streptococcal) (suppurative) (with periostitis)
Excludes1 — never code together — inherited from M86-M90
The conditions below can never be reported together with M86.659 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- postprocedural osteopathies (M96.-)
Excludes1 — never code together — inherited from M86
The conditions below can never be reported together with M86.659 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Use additional code — inherited from M86
Report an additional code alongside M86.659 to fully describe the condition. M86.659 is sequenced first.
Excludes2 — not included here — inherited from Chapter 13
The conditions below are not part of M86.659, but a patient may have both at the same time. When documentation supports it, M86.659 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 M86
The conditions below are not part of M86.659, but a patient may have both at the same time. When documentation supports it, M86.659 and the excluded code may both be reported.
How long has M86.659 existed?
M86.659 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.