M87.075
BillableIdiopathic aseptic necrosis of left foot
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M87.075 an HCC code?
Yes. M87.075 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 M87.075
For M87.075 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 M87.075 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M87.075 is the ICD-10-CM diagnosis code for idiopathic aseptic necrosis of left foot. Death of bone tissue in the left foot without infection, occurring without a known cause. M87.075 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, M87.075 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, M87.075 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.
Confirm left-sided foot involvement is documented before assigning this code. Because M87.075 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 M87.075 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm left-sided foot involvement is documented before assigning this code
- •Review imaging reports to support the diagnosis of idiopathic aseptic necrosis
Clinical Significance
Idiopathic aseptic necrosis of the left foot represents bone death without infection or known cause, requiring ongoing monitoring for potential complications including joint collapse or need for surgical intervention. This diagnosis significantly impacts patient mobility and quality of life, often requiring specialized orthopedic care and potentially leading to disability.
Documentation Requirements
- ✓Specific anatomical location (left foot) clearly documented
- ✓Confirmation of aseptic nature (no infection present)
- ✓Documentation that cause is idiopathic/unknown
- ✓Imaging studies supporting bone necrosis (MRI, bone scan, or X-ray)
- ✓Clinical examination findings consistent with osteonecrosis
- ✓Exclusion of other causes of bone death
- ✓Assessment of functional impact on patient mobility
- ✓Treatment plan and response documentation