M87.273 ICD-10-CM Code: Osteonecrosis due to previous trauma, unspecified ankle
M87.273 maps to CMS-HCC V28 92 (RAF 0.479). Documentation must support MEAT. MEAT criteria · RAF calculator · HCC Buddy coding tools
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FY 2026 Apr update / Diseases of the musculoskeletal system and connective tissue (M00-M99) / Other osteopathies (M86-M90)
M87.273
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOsteonecrosis due to previous trauma, unspecified ankle
Death of bone tissue in the ankle caused by a previous injury, but the specific side (left or right) is not documented.
Buddy Insight
Unspecified ankle osteonecrosis following trauma indicates critical joint pathology affecting weight-bearing capacity and mobility.
CMS-HCC V28
MappedHCC 92
RAF 0.479
CMS-HCC V24
MappedHCC 39
RAF 0.401
ACA/HHS
MappedHCC 55
Varies by metal level
ESRD/PACE
MappedHCC 39
RAF 0.092
RXHCC
MappedHCC 80
RAF 0.204
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for M87.273 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for M87.273 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for M87.273 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for M87.273 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for M87.273 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for M87.273 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for M87.273 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is M87.273 an HCC code?
Yes. M87.273 (Osteonecrosis due to previous trauma, unspecified ankle) maps to Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis under the CMS-HCC V28 risk adjustment model (and Bone/Joint/Muscle Infections/Necrosis under V24), with a community non-dual aged RAF of 0.479. It is billable for payment year 2026.
Coder answer: M87.273 is billable and maps to V28 HCC 92, Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- M87.273
- Description
- Osteonecrosis due to previous trauma, unspecified ankle
- HCC (V28)
- HCC 92 — Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis
- RAF
- 0.479
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. 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.
Work M87.273 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
MEAT Criteria for M87.273
For M87.273 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 M87.273 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
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What This Code Means
M87.273 is the ICD-10-CM diagnosis code for osteonecrosis due to previous trauma, unspecified ankle. Death of bone tissue in the ankle caused by a previous injury, but the specific side (left or right) is not documented. M87.273 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, M87.273 maps to Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis (HCC 92) with a community, non-dual, aged base RAF weight of 0.479. Under the older CMS-HCC V24 model, M87.273 maps to Bone/Joint/Muscle Infections/Necrosis (HCC 39) with a community, non-dual, aged base RAF weight of 0.401. 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.
Use this code only when laterality cannot be determined from medical record. Because M87.273 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 M87.273 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when laterality cannot be determined from medical record
- •Query provider if possible to obtain specific laterality for more precise coding
Clinical Significance
Unspecified ankle osteonecrosis following trauma indicates critical joint pathology affecting weight-bearing capacity and mobility. This condition typically requires comprehensive orthopedic evaluation and may significantly impact patient function, necessitating advanced treatment planning and rehabilitation.
Documentation Requirements
- ✓Documentation of ankle involvement without specified laterality
- ✓Clear history of previous trauma to ankle area
- ✓Evidence of bone necrosis in ankle joint structures
- ✓Justification for unspecified laterality (bilateral involvement or unclear documentation)
- ✓Current weight-bearing capacity and mobility assessment
- ✓Joint stability and range of motion evaluation
- ✓Treatment planning and orthopedic consultation
- ✓Impact on patient independence and daily functioning
Commonly Confused Codes
- •M87.271: Osteonecrosis due to previous trauma, right ankle (when laterality is documented)
- •M87.272: Osteonecrosis due to previous trauma, left ankle (when laterality is documented)
- •M87.373: Other secondary osteonecrosis, unspecified ankle (non-traumatic cause)
- •M87.276: Osteonecrosis due to previous trauma, unspecified foot (different anatomical area)
- •M25.579: Pain in unspecified ankle (symptom without bone necrosis)