What is ICD-10 code M90.532?

M90.532 is the ICD-10-CM diagnosis code for Osteonecrosis in diseases classified elsewhere, left forearm. Death of bone tissue in the left forearm caused by another disease or condition affecting the body. It belongs to the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99). M90.532 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. M90.532 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. M90.532 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. M90.532 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 M90.532?

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. For M90.532, V28 maps to Bone/Joint/Muscle Infections/Necrosis at RAF 0.209 while V24 mapped to Bone/Joint/Muscle Infections/Necrosis at RAF 0.482. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting M90.532?

Document which forearm bone is affected (radius, ulna, or both) for clinical clarity Requires an underlying condition code to explain the etiology of the osteonecrosis Because M90.532 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.

M90.532 ICD-10 Code: Osteonecrosis in diseases

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupM90.532Effective 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)

M90.532

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

Osteonecrosis in diseases classified elsewhere, left forearm

Death of bone tissue in the left forearm caused by another disease or condition affecting the body.

Buddy Insight

This diagnosis represents secondary osteonecrosis affecting the left forearm, indicating bone death caused by an underlying disease process requiring active management.

CMS-HCC V28

Mapped

HCC 92

Bone/Joint/Muscle Infections/...

RAF 0.209

CMS-HCC V24

Mapped

HCC 39

Bone/Joint/Muscle Infections/...

RAF 0.482

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 39

Bone/Joint/Muscle Infections/...

RAF 0.0

RXHCC

Mapped

HCC 80

Bone/Joint/Muscle Infections/...

RAF 0.0

Code Trumping

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Code Book Path

Official

M90.5Osteonecrosis in diseases classified elsewhere

M90.53Osteonecrosis in diseases classified elsewhere, forearm

M90.532Osteonecrosis in diseases classified elsewhere, left forearm

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for M90.532 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for M90.532 in this effective period.

Related Child Codes

Official

M90.531Osteonecrosis in diseases classified elsewhere, right forearm

M90.539Osteonecrosis in diseases classified elsewhere, unspecified forearm

Includes

Official

ICD-10-CM does not list Includes notes for M90.532 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for M90.532 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for M90.532 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for M90.532 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for M90.532 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Clear identification of the specific underlying disease causing the osteonecrosis

Documentation of left forearm as the affected anatomical location

Evidence of bone necrosis through imaging studies (MRI, CT, or bone scan)

Clinical correlation between the primary disease and secondary osteonecrosis

MEAT Support

HCC Buddy guidance

Clear identification of the specific underlying disease causing the osteonecrosis

Documentation of left forearm as the affected anatomical location

Evidence of bone necrosis through imaging studies (MRI, CT, or bone scan)

Clinical correlation between the primary disease and secondary osteonecrosis

Audit Caution

HCC Buddy guidance

Failing to verify the underlying disease is documented and coded separately as required

Coding when documentation only mentions 'possible' or 'suspected' osteonecrosis

Missing the laterality specification and defaulting to unspecified codes

Confusing secondary osteonecrosis with primary avascular necrosis conditions

Common Mistakes

HCC Buddy guidance

M87.032 — Primary osteonecrosis of left forearm, not secondary to another disease

M90.539 — Same condition but unspecified forearm location rather than specifically left

M86.132 — Chronic osteomyelitis with draining sinus of left forearm, which is infection rather than necrosis

S52.92XA — Fracture of left forearm, which is acute trauma rather than disease-related bone death

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 M90.532 an HCC code?

Yes. M90.532 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

V28HCC 92, Bone/Joint/Muscle Infections/Necrosis

0.209

V24HCC 39, Bone/Joint/Muscle Infections/Necrosis

0.482

ESRDHCC 39, Bone/Joint/Muscle Infections/Necrosis

0.000

RxHCCHCC 80, Bone/Joint/Muscle Infections/Necrosis

0.000

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 M90.532

For M90.532to 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 M90.532 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

M90.532 is the ICD-10-CM diagnosis code for osteonecrosis in diseases classified elsewhere, left forearm. Death of bone tissue in the left forearm caused by another disease or condition affecting the body. M90.532 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, M90.532 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, M90.532 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.

Document which forearm bone is affected (radius, ulna, or both) for clinical clarity. Because M90.532 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 M90.532 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Document which forearm bone is affected (radius, ulna, or both) for clinical clarity
•Requires an underlying condition code to explain the etiology of the osteonecrosis

Clinical Significance

This diagnosis represents secondary osteonecrosis affecting the left forearm, indicating bone death caused by an underlying disease process requiring active management. The condition significantly impacts risk adjustment modeling as it reflects complex medical comorbidities and potential functional limitations requiring ongoing specialized care.

Documentation Requirements

✓Clear identification of the specific underlying disease causing the osteonecrosis
✓Documentation of left forearm as the affected anatomical location
✓Evidence of bone necrosis through imaging studies (MRI, CT, or bone scan)
✓Clinical correlation between the primary disease and secondary osteonecrosis
✓Current treatment plan or management approach
✓Assessment of functional impact on the patient
✓Provider statement linking osteonecrosis to the classified disease
✓Documentation ruling out primary osteonecrosis or trauma-related causes

Commonly Confused Codes

•M87.032 — Primary osteonecrosis of left forearm, not secondary to another disease
•M90.539 — Same condition but unspecified forearm location rather than specifically left
•M86.132 — Chronic osteomyelitis with draining sinus of left forearm, which is infection rather than necrosis
•S52.92XA — Fracture of left forearm, which is acute trauma rather than disease-related bone death
•M25.532 — Pain in left forearm, which is symptom-based rather than structural bone pathology