What is ICD-10 code M87.131?

M87.131 is the ICD-10-CM diagnosis code for Osteonecrosis due to drugs of right radius. Death of bone tissue in the right radius (forearm bone) caused by medication side effects. It belongs to the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99). M87.131 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. M87.131 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. M87.131 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. M87.131 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for M87.131?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. M87.131 was a payment HCC under V24 (Bone/Joint/Muscle Infections/Necrosis) but the V28 recalibration removed it from the risk adjustment model. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting M87.131?

Verify the specific drug causing osteonecrosis in the medical record; common culprits include corticosteroids and bisphosphonates Ensure laterality is clearly documented as right; if documentation is unclear, query the provider before coding Because M87.131 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

2026 ICD-10-CM M87.131: Osteonecrosis due to drugs

ICD-10-CM Code View

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Code lookupM87.131Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the musculoskeletal system and connective tissue (M00-M99) / Other osteopathies (M86-M90)

M87.131

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Osteonecrosis due to drugs of right radius

Death of bone tissue in the right radius (forearm bone) caused by medication side effects.

Buddy Insight

Drug-induced osteonecrosis of the right radius indicates medication-related bone death that can compromise forearm function and grip strength.

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

Mapped

HCC 39

Bone/Joint/Muscle Infections/...

RAF 0.401

ACA/HHS

Mapped

HCC 55

HHS-HCC 55

Varies by metal level

ESRD/PACE

Mapped

HCC 39

Bone/Joint/Muscle Infections/...

RAF 0.092

RXHCC

Mapped

HCC 80

Bone/Joint/Muscle Infections/...

RAF 0.204

Code Book Path

Official

M87.1Osteonecrosis due to drugs

M87.13Osteonecrosis due to drugs of radius, ulna and carpus

M87.131Osteonecrosis due to drugs of right radius

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for M87.131 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for M87.131 in this effective period.

Related Child Codes

Official

M87.132Osteonecrosis due to drugs of left radius

M87.133Osteonecrosis due to drugs of unspecified radius

M87.134Osteonecrosis due to drugs of right ulna

M87.135Osteonecrosis due to drugs of left ulna

M87.136Osteonecrosis due to drugs of unspecified ulna

Includes

Official

ICD-10-CM does not list Includes notes for M87.131 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for M87.131 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for M87.131 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for M87.131 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for M87.131 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Clear identification of right radius as the affected bone

Specific medication or drug class responsible for osteonecrosis

Imaging studies confirming bone necrosis (MRI preferred for early detection)

Clinical symptoms including pain, tenderness, or functional limitation

MEAT Support

HCC Buddy guidance

Clear identification of right radius as the affected bone

Specific medication or drug class responsible for osteonecrosis

Imaging studies confirming bone necrosis (MRI preferred for early detection)

Clinical symptoms including pain, tenderness, or functional limitation

Audit Caution

HCC Buddy guidance

Assuming right side when documentation only states 'radius osteonecrosis'

Missing drug causation documentation in favor of other potential causes

Confusing radius with ulnar osteonecrosis in forearm involvement

Using unspecified codes when laterality is clearly documented

Common Mistakes

HCC Buddy guidance

M87.133 — Use when laterality is not specified rather than assuming right side

M87.231 — Post-traumatic osteonecrosis requires injury history, not drug exposure

M87.031 — Idiopathic osteonecrosis lacks drug causation documentation

S52.9 — Acute radius fracture is traumatic injury, not chronic drug-induced necrosis

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is M87.131 an HCC code?

Yes. M87.131 maps to Bone/Joint/Muscle Infections/Necrosis under the V24 model but is not retained in V28.

Code: M87.131
Description: Osteonecrosis due to drugs of right radius
HCC (V28): No CMS-HCC V28 mapping
RAF: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

V24HCC 39, Bone/Joint/Muscle Infections/Necrosis

0.401

ESRDHCC 39, Bone/Joint/Muscle Infections/Necrosis

0.092

RxHCCHCC 80, Bone/Joint/Muscle Infections/Necrosis

0.204

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 M87.131 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for M87.131

For M87.131to 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 M87.131 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

M87.131 is the ICD-10-CM diagnosis code for osteonecrosis due to drugs of right radius. Death of bone tissue in the right radius (forearm bone) caused by medication side effects. M87.131 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, M87.131 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.

Verify the specific drug causing osteonecrosis in the medical record; common culprits include corticosteroids and bisphosphonates. Because M87.131 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 M87.131 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Verify the specific drug causing osteonecrosis in the medical record; common culprits include corticosteroids and bisphosphonates
•Ensure laterality is clearly documented as right; if documentation is unclear, query the provider before coding

Clinical Significance

Drug-induced osteonecrosis of the right radius indicates medication-related bone death that can compromise forearm function and grip strength. This laterality-specific diagnosis is crucial for tracking functional outcomes and planning targeted interventions for the affected extremity.

Documentation Requirements

✓Clear identification of right radius as the affected bone
✓Specific medication or drug class responsible for osteonecrosis
✓Imaging studies confirming bone necrosis (MRI preferred for early detection)
✓Clinical symptoms including pain, tenderness, or functional limitation
✓Timeline of drug exposure relative to symptom onset
✓Assessment of impact on activities of daily living
✓Treatment modalities including conservative vs surgical management
✓Provider statement establishing drug causation

Commonly Confused Codes

•M87.133: Use when laterality is not specified rather than assuming right side
•M87.231: Post-traumatic osteonecrosis requires injury history, not drug exposure
•M87.031: Idiopathic osteonecrosis lacks drug causation documentation
•S52.9: Acute radius fracture is traumatic injury, not chronic drug-induced necrosis
•M87.132: Left radius osteonecrosis, not right side