M87.242
BillableOsteonecrosis due to previous trauma, left hand
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M87.242 an HCC code?
Yes. M87.242 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 M87.242
For M87.242 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 M87.242 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M87.242 is the ICD-10-CM diagnosis code for osteonecrosis due to previous trauma, left hand. Death of bone tissue in the left hand caused by a previous injury, affecting the overall structure and function of the hand. M87.242 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, M87.242 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, M87.242 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.
Ensure left laterality is clearly documented before assigning this code. Because M87.242 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 M87.242 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Ensure left laterality is clearly documented before assigning this code
- •Consider if documentation specifies individual fingers, which would require M87.245 instead
Clinical Significance
Left hand osteonecrosis secondary to trauma significantly impacts fine motor skills and daily functioning, particularly concerning if affecting the dominant hand. This condition requires multidisciplinary management including orthopedic surgery, occupational therapy, and pain management to optimize outcomes.
Documentation Requirements
- ✓Specific documentation of left hand involvement
- ✓Clear history of trauma to the left hand area
- ✓Imaging or clinical evidence of bone death in hand structures
- ✓Assessment of dominant versus non-dominant hand impact
- ✓Current pain levels and functional capacity
- ✓Specific bones affected (metacarpals, phalanges, or multiple)
- ✓Treatment modalities attempted and patient response
- ✓Occupational and social impact assessment
Commonly Confused Codes
- •M87.241 — Osteonecrosis due to previous trauma, right hand (wrong laterality)
- •M87.243 — Osteonecrosis due to previous trauma, unspecified hand (when laterality is documented)
- •M87.245 — Osteonecrosis due to previous trauma, left finger(s) (more specific involvement)
- •M87.342 — Other secondary osteonecrosis, left hand (non-traumatic secondary cause)
- •M87.238 — Osteonecrosis due to previous trauma of left carpus (carpal bones specifically)