M87.077
BillableIdiopathic aseptic necrosis of right toe(s)
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M87.077 an HCC code?
Yes. M87.077 maps to Bone/Joint/Muscle/Severe Soft Tissue 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 M87.077
For M87.077to 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 M87.077 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M87.077 is the ICD-10-CM diagnosis code for idiopathic aseptic necrosis of right toe(s). Death of bone tissue in the right toe(s) without infection, occurring without a known cause. M87.077 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, M87.077 maps to Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis (HCC 92) with a community, non-dual, aged base RAF weight of 0.479. Under the older CMS-HCC V24 model, M87.077 maps to Bone/Joint/Muscle Infections/Necrosis (HCC 39) with a community, non-dual, aged base RAF weight of 0.401. 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.
Verify that the right toe(s) are affected; this code is specific to the right side. Because M87.077 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 M87.077 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify that the right toe(s) are affected; this code is specific to the right side
- •Document which specific toe(s) are involved if possible, though this code covers all right toes
Clinical Significance
Idiopathic aseptic necrosis of right toe(s) represents bone death in the digits without infection or identifiable cause, potentially affecting patient mobility and requiring specialized care. This condition may progress to joint collapse or deformity, necessitating ongoing orthopedic monitoring and possible surgical intervention.
Documentation Requirements
- ✓Specific documentation of right toe(s) involvement
- ✓Confirmation of aseptic nature (no infection)
- ✓Clear documentation that cause is unknown/idiopathic
- ✓Imaging studies demonstrating bone necrosis
- ✓Clinical findings consistent with osteonecrosis
- ✓Exclusion of drug-related or trauma-related causes
- ✓Assessment of impact on ambulation and function
- ✓Number of toes affected if multiple
Commonly Confused Codes
- •M87.177 — Drug-induced osteonecrosis of right toe(s) (requires medication cause)
- •M87.277 — Trauma-related osteonecrosis of right toe(s) (requires injury history)
- •M87.078 — Left toe(s) osteonecrosis (wrong laterality)
- •M86.171 — Chronic osteomyelitis of right toe (infectious process)
- •M20.1 — Hallux valgus (different condition affecting toe structure)