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M87.076 ICD-10-CM Code: Idiopathic aseptic necrosis of unspecified foot

M87.076 maps to CMS-HCC V28 92. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software

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Code lookupM87.076

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

M87.076

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

Idiopathic aseptic necrosis of unspecified foot

Death of bone tissue in the foot without infection and without a known cause, when the side is not specified.

Buddy the Bee presenting code insight

Buddy Insight

Idiopathic aseptic necrosis of unspecified foot indicates bone death of unknown cause when laterality is not documented, representing a significant diagnostic finding requiring further evaluation and ongoing care.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 92

Coefficient HCC 92: 0.479 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 055

Code-level coefficient reference

ESRD/PACE

HCC 39

Code-level coefficient reference

RXHCC

HCC 80

Code-level coefficient reference

Code Book Path

Official
M87.0Idiopathic aseptic necrosis of boneM87.07Idiopathic aseptic necrosis of ankle, foot and toesM87.076Idiopathic aseptic necrosis of unspecified foot

Inclusion Terms

Official
  • Idiopathic aseptic necrosis of metatarsus, tarsus, and phalanges of toesInherited from M87.07

Excludes 2

Official
  • arthropathic psoriasis (L40.5-)Inherited from M00-M99
  • certain conditions originating in the perinatal period (P04-P96)Inherited from M00-M99
  • certain infectious and parasitic diseases (A00-B99)Inherited from M00-M99
  • compartment syndrome (traumatic) (T79.A-)Inherited from M00-M99
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from M00-M99
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from M00-M99
  • endocrine, nutritional and metabolic diseases (E00-E88)Inherited from M00-M99
  • injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from M00-M99
  • neoplasms (C00-D49)Inherited from M00-M99
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from M00-M99

Related Codes

Official
M87.071Idiopathic aseptic necrosis of right ankleM87.072Idiopathic aseptic necrosis of left ankleM87.073Idiopathic aseptic necrosis of unspecified ankleM87.074Idiopathic aseptic necrosis of right footM87.075Idiopathic aseptic necrosis of left foot

Includes

Official
  • avascular necrosis of boneInherited from M87

Excludes 1

Official
  • postprocedural osteopathies (M96.-)Inherited from M86-M90, M87
  • juvenile osteonecrosis (M91-M92)Inherited from M86-M90, M87
  • osteochondropathies (M90-M93)Inherited from M86-M90, M87

Code First

Official

No Code First sequencing instructions are included in this display for M87.076. Check the code and parent instructions in the Code Book.

Use Additional

Official
  • code to identify major osseous defect, if applicable (M89.7-)Inherited from M87

Code Also

Official

No Code Also instructions are included in this display for M87.076. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance
Documentation of foot involvement without side specification
Confirmation of aseptic nature (no infection present)
Clear statement that cause is idiopathic/unknown
Imaging evidence of bone necrosis

MEAT Support

HCC Buddy guidance
Documentation of foot involvement without side specification
Confirmation of aseptic nature (no infection present)
Clear statement that cause is idiopathic/unknown
Imaging evidence of bone necrosis

Audit Caution

HCC Buddy guidance
Using when laterality is actually documented in the record
Not confirming absence of identifiable cause
Failing to rule out infectious etiology
Missing opportunities to specify laterality with additional documentation

Common Mistakes

HCC Buddy guidance
M87.075 — Left foot osteonecrosis (use when laterality is documented)
M87.074 — Right foot osteonecrosis (use when laterality is documented)
M87.176 — Drug-induced osteonecrosis of unspecified foot (requires medication cause)
M87.276 — Trauma-related osteonecrosis of unspecified foot (requires injury history)

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 M87.076 an HCC code?

Yes. M87.076 (Idiopathic aseptic necrosis of unspecified foot) maps to HCC 92, Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.479. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: M87.076 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
M87.076
Description
Idiopathic aseptic necrosis of unspecified foot
HCC (V28)
HCC 92 — Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis
RAF reference coefficient
0.479
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 92, Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis
0.479
ESRDHCC 39, Bone/Joint/Muscle Infections/Necrosis
Not separately weighted
RxHCCHCC 80, Aseptic Necrosis of Bone
Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work M87.076 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for M87.076

For M87.076, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

  • 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

Coder workflow notes

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What This Code Means

M87.076 is the ICD-10-CM diagnosis code for idiopathic aseptic necrosis of unspecified foot. Death of bone tissue in the foot without infection and without a known cause, when the side is not specified. M87.076 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, M87.076 maps to Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis (HCC 92) with a source-labeled community, non-dual, aged reference coefficient of 0.479. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Use only when laterality cannot be determined from available documentation. For M87.076, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for M87.076 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
  • •Attempt to obtain clarification on which foot is affected to assign a more specific code

Clinical Significance

Idiopathic aseptic necrosis of unspecified foot indicates bone death of unknown cause when laterality is not documented, representing a significant diagnostic finding requiring further evaluation and ongoing care. This diagnosis suggests inadequate documentation specificity and may indicate need for additional clinical assessment to determine affected side.

Documentation Requirements

  • ✓Documentation of foot involvement without side specification
  • ✓Confirmation of aseptic nature (no infection present)
  • ✓Clear statement that cause is idiopathic/unknown
  • ✓Imaging evidence of bone necrosis
  • ✓Clinical examination consistent with osteonecrosis
  • ✓Exclusion of infectious and other secondary causes
  • ✓Functional assessment documentation
  • ✓Evidence that laterality could not be determined

Commonly Confused Codes

  • •M87.075: Left foot osteonecrosis (use when laterality is documented)
  • •M87.074: Right foot osteonecrosis (use when laterality is documented)
  • •M87.176: Drug-induced osteonecrosis of unspecified foot (requires medication cause)
  • •M87.276: Trauma-related osteonecrosis of unspecified foot (requires injury history)
  • •M86.9: Osteomyelitis unspecified (infectious process)

Child Codes

M87.071Idiopathic aseptic necrosis of right ankle
HCC 92
M87.072Idiopathic aseptic necrosis of left ankle
HCC 92
M87.073Idiopathic aseptic necrosis of unspecified ankle
HCC 92
M87.074Idiopathic aseptic necrosis of right foot
HCC 92
M87.075Idiopathic aseptic necrosis of left foot
HCC 92
M87.076Idiopathic aseptic necrosis of unspecified foot
HCC 92
M87.077Idiopathic aseptic necrosis of right toe(s)
HCC 92
M87.078Idiopathic aseptic necrosis of left toe(s)
HCC 92
M87.079Idiopathic aseptic necrosis of unspecified toe(s)
HCC 92

Code Hierarchy

└M87Osteonecrosis└M87.0Idiopathic aseptic necrosis of bone└M87.07Idiopathic aseptic necrosis of ankle, foot and toes└M87.076Idiopathic aseptic necrosis of unspecified foot
└M87.076Idiopathic aseptic necrosis of unspecified foot

Also searched as

  • M87 076
  • M87076

For M87.076, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

M87.076 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. The mapping identifies a payment HCC category for M87.076. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

Work M87.076 in HCC Buddy

Open M87.076 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.

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