2027 ICD-10-CM Diagnosis Code M77.50Other enthesopathy of unspecified foot and ankle
ICD-10-CM Codes›M00–M99›M70-M79›M77
- Billable — Valid for Submission
- Not Chronic
M77.50 is a billable ICD-10-CM diagnosis code for other enthesopathy of unspecified foot and ankle. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 557 through 558. Coders also document this condition as bursitis of foot region. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Tendon and synovial disorders.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Bursitis of foot region
- Disorder of flexor hallucis longus tendon
- Enthesopathy of ankle AND/OR tarsus
- Enthesopathy of ankle region
- Intermetatarsal bursitis
- Tendinitis of flexor hallucis longus
- Tendinitis of foot
- Tendinitis of metatarsophalangeal joint of second toe
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to M77.50: its own notes plus those printed at M77 and Chapter 13. A note printed at a category, block or chapter applies to every code under it.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may 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)
Notes
General instructions on how these codes are used.
- Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name M77.50, its category, or a range that includes it.
Excludes1 2
These codes carry an Excludes1 note naming M77.50: they are not reported together with it, unless the two conditions are unrelated.
Excludes2 2
These codes carry an Excludes2 note naming M77.50: its condition is not part of those codes, and both may be reported when the patient has both.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Foot Injuries and Disorders
Each of your feet has 26 bones, 33 joints, and more than 100 tendons, muscles, and ligaments. No wonder a lot of things can go wrong. Here are a few common problems:
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M77.50 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M77.50Overview
What is the ICD-10 code for other enthesopathy of unspecified foot and ankle?
The ICD-10-CM code for other enthesopathy of unspecified foot and ankle is M77.50 (sometimes written as M7750). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is M77.50 (Other enthesopathy of foot and ankle) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other enthesopathy of unspecified foot and ankle on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does M77.50 group to?
When other enthesopathy of unspecified foot and ankle is the principal diagnosis on an inpatient stay, it groups to MS-DRG 557, 558, with relative weights from 0.8873 to 1.4883 depending on complications. Higher weights mean higher Medicare reimbursement.
Can M77.50 be reported with a code from M71.9?
Not as a rule. The Excludes1 note at M77, which applies to M77.50, lists "bursitis NOS (M71.9-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What is the ICD-9 equivalent of M77.50?
Under the General Equivalence Mappings, other enthesopathy of unspecified foot and ankle converts to ICD-9-CM 726.79 (ankle enthesopathy NEC). The mapping is approximate, so confirm the match fits the documentation.
