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M87.876 ICD-10-CM Code: Other osteonecrosis, unspecified foot

M87.876 maps to CMS-HCC V28 92 (RAF 0.479). Documentation must support MEAT. MEAT criteria · RAF calculator · HCC Buddy coding tools

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

M87.876

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

Other osteonecrosis, unspecified foot

Death of bone tissue in an unspecified foot due to causes other than trauma, infection, or radiation. This condition can lead to pain, limited mobility, and potential complications if untreated.

Buddy the Bee presenting code insight

Buddy Insight

Unspecified foot osteonecrosis represents avascular bone death affecting foot structures without documented laterality, potentially indicating bilateral involvement or incomplete documentation.

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
M87.8Other osteonecrosis
M87.87Other osteonecrosis, ankle, foot and toes
M87.876Other osteonecrosis, unspecified foot

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for M87.876 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for M87.876 in this effective period.

Related Child Codes

Official
M87.871Other osteonecrosis, right ankle
M87.872Other osteonecrosis, left ankle
M87.873Other osteonecrosis, unspecified ankle
M87.874Other osteonecrosis, right foot
M87.875Other osteonecrosis, left foot

Includes

Official

ICD-10-CM does not list Includes notes for M87.876 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for M87.876 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for M87.876 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for M87.876 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for M87.876 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Documentation of foot osteonecrosis without laterality specification
Bilateral foot imaging if both feet potentially affected
Exclusion of trauma, infection, and radiation as causes
Assessment of bilateral weight-bearing if applicable

MEAT Support

HCC Buddy guidance
Documentation of foot osteonecrosis without laterality specification
Bilateral foot imaging if both feet potentially affected
Exclusion of trauma, infection, and radiation as causes
Assessment of bilateral weight-bearing if applicable

Audit Caution

HCC Buddy guidance
Using unspecified codes when laterality is available in records
Confusing symptomatic foot pain with structural osteonecrosis
Missing bilateral involvement requiring separate coding
Failing to query for laterality when documentation incomplete

Common Mistakes

HCC Buddy guidance
M87.376 — Drug-induced osteonecrosis requires medication causation documentation
M87.176 — Traumatic osteonecrosis needs clear injury history
M87.076 — Idiopathic osteonecrosis lacks identifiable underlying etiology
M19.079 — Unspecified foot osteoarthritis is degenerative joint disease

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 M87.876 an HCC code?

Yes. M87.876 (Other osteonecrosis, unspecified foot) 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: M87.876 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
M87.876
Description
Other osteonecrosis, unspecified foot
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 M87.876 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for M87.876

For M87.876 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 M87.876 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

M87.876 is the ICD-10-CM diagnosis code for other osteonecrosis, unspecified foot. Death of bone tissue in an unspecified foot due to causes other than trauma, infection, or radiation. This condition can lead to pain, limited mobility, and potential complications if untreated. M87.876 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, M87.876 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, M87.876 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.

Specify the laterality (right vs. left foot) when documented; use M87.875 for right foot or M87.876 for left foot if specified. Because M87.876 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 M87.876 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Specify the laterality (right vs. left foot) when documented; use M87.875 for right foot or M87.876 for left foot if specified
  • •Investigate the underlying cause of osteonecrosis (idiopathic, corticosteroid use, sickle cell disease) as it may require additional coding

Clinical Significance

Unspecified foot osteonecrosis represents avascular bone death affecting foot structures without documented laterality, potentially indicating bilateral involvement or incomplete documentation. This condition significantly impacts weight-bearing and mobility, requiring comprehensive foot care management.

Documentation Requirements

  • ✓Documentation of foot osteonecrosis without laterality specification
  • ✓Bilateral foot imaging if both feet potentially affected
  • ✓Exclusion of trauma, infection, and radiation as causes
  • ✓Assessment of bilateral weight-bearing if applicable
  • ✓Pain evaluation and ambulatory capacity
  • ✓Underlying condition screening and management
  • ✓Coordinated care with foot and ankle specialists
  • ✓Adaptive equipment and mobility aid assessment

Commonly Confused Codes

  • •M87.376: Drug-induced osteonecrosis requires medication causation documentation
  • •M87.176: Traumatic osteonecrosis needs clear injury history
  • •M87.076: Idiopathic osteonecrosis lacks identifiable underlying etiology
  • •M19.079: Unspecified foot osteoarthritis is degenerative joint disease
  • •M79.673: Foot pain is symptomatic condition, not structural bone death

Child Codes

M87.871Other osteonecrosis, right ankle
HCC 92
M87.872Other osteonecrosis, left ankle
HCC 92
M87.873Other osteonecrosis, unspecified ankle
HCC 92
M87.874Other osteonecrosis, right foot
HCC 92
M87.875Other osteonecrosis, left foot
HCC 92
M87.876Other osteonecrosis, unspecified foot
HCC 92
M87.877Other osteonecrosis, right toe(s)
HCC 92
M87.878Other osteonecrosis, left toe(s)
HCC 92
M87.879Other osteonecrosis, unspecified toe(s)
HCC 92

Code Hierarchy

└M87Osteonecrosis└M87.8Other osteonecrosis└M87.87Other osteonecrosis, ankle, foot and toes└M87.876Other osteonecrosis, unspecified foot
└M87.876Other osteonecrosis, unspecified foot

Because M87.876 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.

M87.876 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 M87.876 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.

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