M87.877
BillableOther osteonecrosis, right toe(s)
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M87.877 an HCC code?
Yes. M87.877 maps to Bone/Joint/Muscle Infections/Necrosis under the CMS-HCC V28 risk adjustment model (and Bone/Joint/Muscle Infections/Necrosis under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for M87.877
For M87.877 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed M87.877 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M87.877 is the ICD-10-CM diagnosis code for other osteonecrosis, right toe(s). Death of bone tissue in the right toe(s) due to causes other than trauma, infection, or radiation. This can cause pain and difficulty walking or wearing shoes. M87.877 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering other osteopathies (m86-m90).
Under the CMS-HCC V28 risk adjustment model, M87.877 maps to Bone/Joint/Muscle Infections/Necrosis (HCC 92) with a community, non-dual, aged base RAF weight of 0.209. Under the older V24 model, M87.877 mapped to the same category but with a base RAF weight of 0.482 — V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
This code is specific to the right toe(s); use M87.878 for left toe(s) or M87.879 for unspecified. Because M87.877 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for M87.877 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Right toe osteonecrosis involves avascular bone death in the toe bones, potentially affecting balance, gait mechanics, and weight distribution during ambulation. Though affecting smaller bones, this condition can significantly impact quality of life and mobility.
Documentation Requirements
- ✓Specific identification of right toe(s) involvement
- ✓Imaging confirmation of osteonecrosis in toe bones
- ✓Documentation excluding trauma, infection, or radiation causes
- ✓Assessment of impact on gait and balance
- ✓Pain evaluation and functional limitations
- ✓Evaluation for predisposing conditions (diabetes, vascular disease)
- ✓Footwear modification and offloading strategies
- ✓Monitoring for complications like ulceration or infection
Commonly Confused Codes
- •M87.377 — Drug-induced osteonecrosis requires causative medication identification
- •M87.177 — Traumatic osteonecrosis needs documented injury history
- •M87.077 — Idiopathic osteonecrosis lacks identifiable underlying cause
- •S92.501A — Toe fracture is acute injury, not chronic bone death
- •L97.911 — Diabetic foot ulcer is soft tissue, not bone pathology