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M87.043 ICD-10-CM Code: Idiopathic aseptic necrosis of unspecified hand

M87.043 maps to CMS-HCC V28 92 (RAF 0.479). Documentation must support MEAT. 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)

M87.043

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

Idiopathic aseptic necrosis of unspecified hand

Death of bone tissue in the hand (excluding fingers) without infection when the side is not specified or documented.

Buddy the Bee presenting code insight

Buddy Insight

Idiopathic aseptic necrosis of unspecified hand represents bone death in hand structures when laterality is not documented, indicating a condition that can severely impact hand function and grip strength.

CMS-HCC V28

HCC 92

RAF 0.479

CMS-HCC V24

HCC 39

RAF 0.401

ACA/HHS

HCC 55

Varies by metal level

ESRD/PACE

HCC 39

RAF 0.092

RXHCC

HCC 80

RAF 0.204

Code Book Path

Official
M87.0Idiopathic aseptic necrosis of bone
M87.04Idiopathic aseptic necrosis of hand and fingers
M87.043Idiopathic aseptic necrosis of unspecified hand

Inclusion Terms

Official
  • Idiopathic aseptic necrosis of metacarpals and phalanges of hands

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for M87.043 in this effective period.

Related Child Codes

Official
M87.041Idiopathic aseptic necrosis of right hand
M87.042Idiopathic aseptic necrosis of left hand
M87.044Idiopathic aseptic necrosis of right finger(s)
M87.045Idiopathic aseptic necrosis of left finger(s)
M87.046Idiopathic aseptic necrosis of unspecified finger(s)

Includes

Official

ICD-10-CM does not list Includes notes for M87.043 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for M87.043 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for M87.043 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for M87.043 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for M87.043 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Documentation of aseptic necrosis affecting hand bones
Confirmation of idiopathic etiology without identifiable cause
Imaging studies showing bone necrosis in hand metacarpal structures
Absence of specific laterality documentation in medical record

MEAT Support

HCC Buddy guidance
Documentation of aseptic necrosis affecting hand bones
Confirmation of idiopathic etiology without identifiable cause
Imaging studies showing bone necrosis in hand metacarpal structures
Absence of specific laterality documentation in medical record

Audit Caution

HCC Buddy guidance
Using unspecified code when laterality is documented elsewhere
Missing opportunities for higher specificity when side is mentioned
Confusing hand codes with finger-specific codes when digits involved
Failing to identify medication or trauma causes requiring different codes

Common Mistakes

HCC Buddy guidance
M87.041 — Right hand when laterality is actually documented
M87.042 — Left hand when side is specified in record
M87.143 — Drug-induced unspecified hand osteonecrosis
M87.243 — Trauma-related unspecified hand osteonecrosis

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 M87.043 an HCC code?

Yes. M87.043 (Idiopathic aseptic necrosis of unspecified hand) 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: M87.043 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
M87.043
Description
Idiopathic aseptic necrosis of unspecified hand
HCC (V28)
HCC 92 — Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis
RAF
0.479
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 92, Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis
0.479
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 M87.043 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for M87.043

For M87.043 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 M87.043 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

M87.043 is the ICD-10-CM diagnosis code for idiopathic aseptic necrosis of unspecified hand. Death of bone tissue in the hand (excluding fingers) without infection when the side is not specified or documented. M87.043 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, M87.043 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, M87.043 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 only when laterality cannot be determined from available documentation. Because M87.043 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 M87.043 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • Use only when laterality cannot be determined from available documentation
  • Query the provider to obtain specific right or left designation if possible

Clinical Significance

Idiopathic aseptic necrosis of unspecified hand represents bone death in hand structures when laterality is not documented, indicating a condition that can severely impact hand function and grip strength. This diagnosis requires hand surgery evaluation and specialized management to preserve hand function and prevent progressive bone collapse.

Documentation Requirements

  • Documentation of aseptic necrosis affecting hand bones
  • Confirmation of idiopathic etiology without identifiable cause
  • Imaging studies showing bone necrosis in hand metacarpal structures
  • Absence of specific laterality documentation in medical record
  • Exclusion of infectious causes through clinical assessment
  • Hand functional assessment including grip strength and dexterity
  • Treatment plan documentation including therapeutic interventions
  • Pain management strategies and functional impact on hand activities

Commonly Confused Codes

  • M87.041: Right hand when laterality is actually documented
  • M87.042: Left hand when side is specified in record
  • M87.143: Drug-induced unspecified hand osteonecrosis
  • M87.243: Trauma-related unspecified hand osteonecrosis
  • M87.046: Unspecified finger(s) when digits are specifically affected

Child Codes

Code Hierarchy

Because M87.043 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.

M87.043 maps to CMS-HCC V28 category 92, Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. Because M87.043 carries a payment HCC, you can see what it adds to a RAF score and check the documentation the chart needs before it is submitted.

Work M87.043 in HCC Buddy

Open M87.043 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.