M87.031
BillableIdiopathic aseptic necrosis of right radius
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M87.031 an HCC code?
Yes. M87.031 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 M87.031
For M87.031 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 M87.031 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M87.031 is the ICD-10-CM diagnosis code for idiopathic aseptic necrosis of right radius. Death of bone tissue without infection in the right forearm bone (radius), occurring without a known cause. M87.031 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, M87.031 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, M87.031 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.
The radius is the larger forearm bone on the thumb side; distinguish from ulna. Because M87.031 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 M87.031 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •The radius is the larger forearm bone on the thumb side; distinguish from ulna
- •Ensure right side is documented to use this specific laterality code
Clinical Significance
Idiopathic aseptic necrosis of the right radius represents bone death in the forearm without identifiable cause, potentially affecting wrist function and grip strength. This condition can significantly impact hand and wrist mobility, requiring specialized orthopedic care and potentially surgical intervention to prevent further bone collapse.
Documentation Requirements
- ✓Documentation of aseptic necrosis specifically affecting right radius bone
- ✓Confirmation of idiopathic etiology with no underlying cause identified
- ✓Imaging evidence demonstrating bone necrosis in right radial structures
- ✓Clear laterality documentation specifying right side involvement
- ✓Clinical exclusion of infectious processes
- ✓Assessment of wrist and forearm function and range of motion
- ✓Treatment plan documentation including therapeutic approaches
- ✓Documentation of pain and functional limitations in daily activities