M87.121 ICD-10-CM Code: Osteonecrosis due to drugs, right humerus
M87.121 is not a CMS-HCC payment code. MEAT criteria · RAF calculator · HCC coding software
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FY 2026 Apr update / Diseases of the musculoskeletal system and connective tissue (M00-M99) / Other osteopathies (M86-M90)
M87.121
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOsteonecrosis due to drugs, right humerus
Death of bone tissue in the right upper arm bone (humerus) caused by medication use.
Buddy Insight
Drug-induced osteonecrosis of the right humerus represents serious medication-related bone death affecting the upper arm bone, requiring immediate evaluation of causative agents and treatment 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 M87.121 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for M87.121 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for M87.121 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for M87.121 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for M87.121 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for M87.121 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for M87.121 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 M87.121 an HCC code?
Yes. M87.121 maps to Bone/Joint/Muscle Infections/Necrosis under the V24 model but is not retained in V28.
- Code
- M87.121
- Description
- Osteonecrosis due to drugs, right humerus
- 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 M87.121 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
MEAT Criteria for M87.121
For M87.121 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 M87.121 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
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What This Code Means
M87.121 is the ICD-10-CM diagnosis code for osteonecrosis due to drugs, right humerus. Death of bone tissue in the right upper arm bone (humerus) caused by medication use. M87.121 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, M87.121 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.
Distinguish between shoulder (M87.11x) and humerus (M87.12x) locations. Because M87.121 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 M87.121 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Drug-induced osteonecrosis of the right humerus represents serious medication-related bone death affecting the upper arm bone, requiring immediate evaluation of causative agents and treatment modifications. This condition can significantly impact arm function and strength, often necessitating surgical intervention and comprehensive rehabilitation.
Documentation Requirements
- ✓Specific documentation of right humerus involvement
- ✓Clear identification of drug-induced etiology
- ✓Documentation of causative medication(s)
- ✓Imaging studies confirming humeral osteonecrosis
- ✓Timeline establishing drug exposure relationship
- ✓Assessment of right arm function and strength
- ✓Evaluation for medication discontinuation or modification
- ✓Treatment plan including potential surgical options
Commonly Confused Codes
- •M87.021: Idiopathic osteonecrosis of right humerus (no drug cause)
- •M87.221: Trauma-related osteonecrosis of right humerus (injury-related)
- •M87.321: Other secondary osteonecrosis of right humerus (different cause)
- •M87.122: Drug-induced osteonecrosis of left humerus (wrong laterality)
- •M84.421: Pathological fracture of right humerus (different pathology)