M87.877 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 lookupM87.877

Effective 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)

M87.877

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

Other osteonecrosis, right toe(s)

Death of bone tissue in the right toe(s) due to causes other than trauma, infection, or radiation. This can cause pain and difficulty walking or wearing shoes.

Buddy Insight

Right toe osteonecrosis involves avascular bone death in the toe bones, potentially affecting balance, gait mechanics, and weight distribution during ambulation.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 92

Bone/Joint/Muscle/Severe Soft...

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

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 055

HHS-HCC 055 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 39

Bone/Joint/Muscle Infections/...

Code-level coefficient reference

RXHCC

Mapped

HCC 80

Aseptic Necrosis of Bone

Code-level coefficient reference

Code Book Path

Official

M87.8Other osteonecrosis M87.87Other osteonecrosis, ankle, foot and toes M87.877Other osteonecrosis, right toe(s)

Inclusion Terms

Official

No inclusion terms are included in this display for M87.877. Check the code and parent instructions in the Code Book.

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

M87.871Other 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

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 M87.877. 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 M87.877. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Specific identification of right toe(s) involvement

Imaging confirmation of osteonecrosis in toe bones

Documentation excluding trauma, infection, or radiation causes

Assessment of impact on gait and balance

MEAT Support

HCC Buddy guidance

Specific identification of right toe(s) involvement

Imaging confirmation of osteonecrosis in toe bones

Documentation excluding trauma, infection, or radiation causes

Assessment of impact on gait and balance

Audit Caution

HCC Buddy guidance

Using unspecified toe codes when right side is documented

Confusing acute toe injuries with chronic osteonecrosis

Missing associated diabetic complications that should be coded separately

Incorrectly coding soft tissue ulcers as bone pathology

Common Mistakes

HCC Buddy guidance

M87.377 — Drug-induced osteonecrosis requires causative medication identification

M87.177 — Traumatic osteonecrosis needs documented injury history

M87.077 — Idiopathic osteonecrosis lacks identifiable underlying cause

S92.501A — Toe fracture is acute injury, not chronic bone death

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 M87.877 an HCC code?

Yes. M87.877 (Other osteonecrosis, right toe(s)) 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: M87.877 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: M87.877
Description: Other osteonecrosis, right toe(s)
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 M87.877 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for M87.877

For M87.877, 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

M87.877 is the ICD-10-CM diagnosis code for other osteonecrosis, right toe(s). Death of bone tissue in the right toe(s) due to causes other than trauma, infection, or radiation. This can cause pain and difficulty walking or wearing shoes. M87.877 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, M87.877 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.

This code is specific to the right toe(s); use M87.878 for left toe(s) or M87.879 for unspecified. For M87.877, 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 M87.877 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This code is specific to the right toe(s); use M87.878 for left toe(s) or M87.879 for unspecified
•Document which toe(s) are affected if possible, though this code does not differentiate between individual toes

Clinical Significance

Right toe osteonecrosis involves avascular bone death in the toe bones, potentially affecting balance, gait mechanics, and weight distribution during ambulation. Though affecting smaller bones, this condition can significantly impact quality of life and mobility.

Documentation Requirements

✓Specific identification of right toe(s) involvement
✓Imaging confirmation of osteonecrosis in toe bones
✓Documentation excluding trauma, infection, or radiation causes
✓Assessment of impact on gait and balance
✓Pain evaluation and functional limitations
✓Evaluation for predisposing conditions (diabetes, vascular disease)
✓Footwear modification and offloading strategies
✓Monitoring for complications like ulceration or infection

Commonly Confused Codes

•M87.377: Drug-induced osteonecrosis requires causative medication identification
•M87.177: Traumatic osteonecrosis needs documented injury history
•M87.077: Idiopathic osteonecrosis lacks identifiable underlying cause
•S92.501A: Toe fracture is acute injury, not chronic bone death
•L97.911: Diabetic foot ulcer is soft tissue, not bone pathology