M87.844
BillableOther osteonecrosis, right finger(s)
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M87.844 an HCC code?
Yes. M87.844 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 M87.844
For M87.844 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 M87.844 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M87.844 is the ICD-10-CM diagnosis code for other osteonecrosis, right finger(s). Death of bone tissue in one or more fingers of the right hand due to interrupted blood supply. M87.844 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, M87.844 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, M87.844 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 applies to any finger(s) on the right hand; document which specific fingers are affected in clinical notes. Because M87.844 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 M87.844 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code applies to any finger(s) on the right hand; document which specific fingers are affected in clinical notes
- •Distinguish from thumb involvement, which may have separate coding considerations
Clinical Significance
Osteonecrosis affecting the right finger(s) can cause significant functional impairment and chronic pain, potentially affecting fine motor skills and activities of daily living. This diagnosis is important for risk adjustment as it represents a complex condition requiring specialized care and possible surgical intervention.
Documentation Requirements
- ✓Specific identification of osteonecrosis affecting right finger bones (phalanges)
- ✓Documentation of causes other than idiopathic or drug-induced osteonecrosis
- ✓Imaging confirmation (MRI, X-ray) showing bone necrosis in right finger(s)
- ✓Clinical symptoms including finger pain, stiffness, swelling, or deformity
- ✓Exclusion of infectious or traumatic causes as primary etiology
- ✓Assessment of impact on fine motor function and hand dexterity
- ✓Documentation of which specific fingers are affected if known
- ✓Provider evaluation of treatment options and functional prognosis
Commonly Confused Codes
- •M87.044 — Idiopathic aseptic necrosis of right finger(s) - specifically idiopathic cause
- •M87.049 — Idiopathic aseptic necrosis of unspecified finger(s) - different etiology and lacks laterality
- •M86.844 — Other osteomyelitis, right finger(s) - infectious condition rather than necrosis
- •S62.601A — Fracture of unspecified phalanx of right index finger - acute trauma rather than chronic necrosis
- •M20.011 — Mallet finger of right finger(s) - tendon injury rather than bone necrosis