M87.278
BillableOsteonecrosis due to previous trauma, left toe(s)
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M87.278 an HCC code?
Yes. M87.278 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 M87.278
For M87.278 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 M87.278 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M87.278 is the ICD-10-CM diagnosis code for osteonecrosis due to previous trauma, left toe(s). Death of bone tissue in the left toe(s) caused by a previous injury or trauma. M87.278 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, M87.278 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, M87.278 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.
Confirm laterality is documented as 'left' and identify if single or multiple toes are involved. Because M87.278 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 M87.278 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm laterality is documented as 'left' and identify if single or multiple toes are involved
- •Distinguish toe osteonecrosis from metatarsal or other foot bone involvement
Clinical Significance
Left toe osteonecrosis secondary to trauma affects the terminal weight-bearing structures important for normal gait and balance. This condition can impact push-off mechanics during ambulation and may require specialized foot care to prevent further complications and preserve function.
Documentation Requirements
- ✓Clear identification of left toe(s) involvement
- ✓Documentation of previous trauma to left toe(s)
- ✓Evidence of bone necrosis in left toe bone structures
- ✓Specification of affected toes when documented
- ✓Assessment of gait mechanics and balance impact
- ✓Current pain evaluation and functional capacity
- ✓Treatment modalities attempted and effectiveness
- ✓Impact on ambulation and weight-bearing activities
Commonly Confused Codes
- •M87.277 — Osteonecrosis due to previous trauma, right toe(s) (wrong laterality)
- •M87.279 — Osteonecrosis due to previous trauma, unspecified toe(s) (when laterality is known)
- •M87.275 — Osteonecrosis due to previous trauma, left foot (broader anatomical involvement)
- •M87.378 — Other secondary osteonecrosis, left toe(s) (non-traumatic secondary cause)
- •M79.673 — Pain in left foot (symptom without bone necrosis)