M87.377
BillableOther secondary osteonecrosis, right toe(s)
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M87.377 an HCC code?
Yes. M87.377 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 M87.377
For M87.377 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 M87.377 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M87.377 is the ICD-10-CM diagnosis code for other secondary osteonecrosis, right toe(s). Death of bone tissue in the right toe(s) caused by an underlying condition or treatment such as corticosteroid use or radiation therapy. M87.377 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, M87.377 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, M87.377 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.
Clarify which toe(s) are affected (great toe, lesser toes, or multiple) in the documentation. Because M87.377 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 M87.377 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Clarify which toe(s) are affected (great toe, lesser toes, or multiple) in the documentation
- •Document the secondary cause and any impact on mobility or function
Clinical Significance
This diagnosis represents secondary osteonecrosis of the right toe bones caused by underlying conditions such as corticosteroid use or radiation therapy, which can affect toe function and potentially impact walking. It requires management of the underlying cause and monitoring for progression.
Documentation Requirements
- ✓Documentation of osteonecrosis affecting right toe(s)
- ✓Identification of underlying cause (e.g., corticosteroid use, radiation therapy, vascular disease)
- ✓Imaging findings confirming toe bone necrosis (MRI, X-ray, CT)
- ✓Clinical symptoms such as toe pain, swelling, or deformity
- ✓Specific toe(s) affected if documented
- ✓Functional impact on walking or footwear
- ✓Duration and progression of condition
- ✓Treatment history and response to interventions