M87.861
BillableOther osteonecrosis, right tibia
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M87.861 an HCC code?
Yes. M87.861 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 M87.861
For M87.861 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 M87.861 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M87.861 is the ICD-10-CM diagnosis code for other osteonecrosis, right tibia. Death of bone tissue in the right shinbone (tibia) due to loss of blood supply. M87.861 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, M87.861 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, M87.861 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.
Tibial osteonecrosis is less common than femoral; ensure documentation clearly specifies tibia rather than femur. Because M87.861 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 M87.861 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Tibial osteonecrosis is less common than femoral; ensure documentation clearly specifies tibia rather than femur
- •Document whether involvement is in the proximal, distal, or shaft region of the tibia
Clinical Significance
Right tibial osteonecrosis represents significant bone pathology requiring ongoing monitoring and management to prevent joint collapse and disability. This condition substantially impacts patient mobility and quality of life, necessitating comprehensive care coordination.
Documentation Requirements
- ✓Specific anatomical location (right tibia) documented
- ✓Evidence of bone death/necrosis through imaging studies (MRI, X-ray, bone scan)
- ✓Exclusion of traumatic or radiation-induced causes
- ✓Documentation of underlying etiology if known (steroid use, alcohol, sickle cell, etc.)
- ✓Assessment of pain level and functional limitations
- ✓Treatment plan including weight-bearing restrictions
- ✓Monitoring plan for disease progression
- ✓Evaluation for surgical intervention if indicated