M87.177 ICD-10-CM Code: Osteonecrosis due to drugs, right toe(s)
M87.177 is not a CMS-HCC payment code. 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)
M87.177
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOsteonecrosis due to drugs, right toe(s)
Bone death in the toes of the right foot caused by medication side effects.
Buddy Insight
Drug-induced osteonecrosis of right toe(s) represents medication-related bone death in the digits, requiring immediate evaluation of causative medications and potential therapy modifications.
CMS-HCC V28
N/A—
Not mapped
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 M87.177 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for M87.177 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for M87.177 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for M87.177 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for M87.177 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for M87.177 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for M87.177 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 M87.177 an HCC code?
Yes. M87.177 maps to Bone/Joint/Muscle Infections/Necrosis under the V24 model but is not retained in V28.
- Code
- M87.177
- Description
- Osteonecrosis due to drugs, right toe(s)
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- 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 M87.177 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
MEAT Criteria for M87.177
For M87.177 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 M87.177 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
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What This Code Means
M87.177 is the ICD-10-CM diagnosis code for osteonecrosis due to drugs, right toe(s). Bone death in the toes of the right foot caused by medication side effects. M87.177 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 older CMS-HCC V24 model, M87.177 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.
Document which medication caused the osteonecrosis and link it with a drug adverse effect code if applicable. Because M87.177 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 M87.177 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document which medication caused the osteonecrosis and link it with a drug adverse effect code if applicable
- •Distinguish between single toe involvement and multiple toes; this code indicates right toe(s)
Clinical Significance
Drug-induced osteonecrosis of right toe(s) represents medication-related bone death in the digits, requiring immediate evaluation of causative medications and potential therapy modifications. This condition can significantly impact weight-bearing and ambulation, potentially progressing to deformity or functional disability without appropriate management.
Documentation Requirements
- ✓Specific documentation of right toe(s) involvement
- ✓Clear identification of drug-induced etiology
- ✓Documentation of causative medication(s) when known
- ✓Imaging evidence of toe bone necrosis
- ✓Timeline relationship between drug exposure and bone death
- ✓Assessment of impact on weight-bearing and ambulation
- ✓Number of toes affected if multiple
- ✓Medication review and modification planning
Commonly Confused Codes
- •M87.077: Idiopathic osteonecrosis of right toe(s) (no drug cause)
- •M87.277: Trauma-related osteonecrosis of right toe(s) (injury-related)
- •M87.377: Other secondary osteonecrosis of right toe(s) (different cause)
- •M87.178: Drug-induced osteonecrosis of left toe(s) (wrong laterality)
- •L97.4: Non-pressure chronic ulcer of right heel and midfoot (different pathology)