M87.043
BillableIdiopathic aseptic necrosis of unspecified hand
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M87.043 an HCC code?
Yes. M87.043 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 M87.043
For M87.043 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 M87.043 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M87.043 is the ICD-10-CM diagnosis code for idiopathic aseptic necrosis of unspecified hand. Death of bone tissue in the hand (excluding fingers) without infection when the side is not specified or documented. M87.043 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, M87.043 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, M87.043 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.
Use only when laterality cannot be determined from available documentation. Because M87.043 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 M87.043 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use only when laterality cannot be determined from available documentation
- •Query the provider to obtain specific right or left designation if possible
Clinical Significance
Idiopathic aseptic necrosis of unspecified hand represents bone death in hand structures when laterality is not documented, indicating a condition that can severely impact hand function and grip strength. This diagnosis requires hand surgery evaluation and specialized management to preserve hand function and prevent progressive bone collapse.
Documentation Requirements
- ✓Documentation of aseptic necrosis affecting hand bones
- ✓Confirmation of idiopathic etiology without identifiable cause
- ✓Imaging studies showing bone necrosis in hand metacarpal structures
- ✓Absence of specific laterality documentation in medical record
- ✓Exclusion of infectious causes through clinical assessment
- ✓Hand functional assessment including grip strength and dexterity
- ✓Treatment plan documentation including therapeutic interventions
- ✓Pain management strategies and functional impact on hand activities