M87.879 Other osteonecrosis, unspecified toe(s)

ICD-10-CM M87.879: Other osteonecrosis, unspecified toe(s)

ICD-10-CM code M87.879 designates other osteonecrosis of unspecified toe(s) as an active pathologic function diagnosis. It falls under the parent category of other osteonecrosis affecting the ankle, foot, and toes. This code is utilized when laterality is not specified, distinguishing it from right or left toe diagnoses. 1 3

Plain-language overview

Code M87.879 identifies a pathologic function involving bone death in the toe bones when the specific toe or side is not specified in the clinical documentation. 1 3

What this code represents

The official display label for M87.879 is other osteonecrosis, unspecified toe(s), and the terminology record maintains an active status for this diagnosis concept. 1

M87.879 is a child concept under the parent code M87.87, which categorizes other osteonecrosis of the ankle, foot, and toes in the ICD-10-CM version 2026. 1

Coding details

M87.879 is used for unspecified toe osteonecrosis, whereas M87.877 is used for right toe(s) and M87.878 is used for left toe(s) to specify laterality. 3

M87.879 is listed alongside other osteonecrosis codes including M87.88 for other site and M87.89 for multiple sites within official billing and coding articles. 2

Documentation considerations

Clinical documentation for toe osteonecrosis may include imaging confirmation of the bone condition, which is a factor noted for related toe osteonecrosis codes. 3

What the sources add

The National Cancer Institute terminology record establishes the hierarchical structure and active status of M87.879, while a separate clinical coding source provides laterality distinctions. 1 3

Coverage and utilization context

The code M87.879 appears in a Medicare billing and coding article concerning amniotic and placental-derived product injections for musculoskeletal indications. 2

Questions to verify

Reviewers may verify whether the clinical record contains imaging confirmation of osteonecrosis in the toe bones to support the documented diagnosis code. 3

Sources

1. ICD-10-CM M87.879 terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Article - Billing and Coding: Amniotic and Placental-Derived Product Injections and/or Applications for Musculoskeletal Indications, Non-Wound (A59764) — cms.gov; accessed 2026-07-27.
3. 2026 ICD-10-CM M87.877: Other osteonecrosis, right | HCC 92 — hccbuddy.com; accessed 2026-07-27.