M06.871
BillableOther specified rheumatoid arthritis, right ankle and foot
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M06.871 an HCC code?
Yes. M06.871 maps to Rheumatoid Arthritis and Inflammatory Connective Tissue Disease under the CMS-HCC V28 risk adjustment model (and Rheumatoid Arthritis and Inflammatory Connective Tissue Disease under V24).
HCC Category Mapping
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 M06.871
For M06.871to 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 M06.871 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M06.871 is the ICD-10-CM diagnosis code for other specified rheumatoid arthritis, right ankle and foot. A form of rheumatoid arthritis affecting the right ankle and foot, characterized by inflammation and joint damage that doesn't fit into other specific rheumatoid arthritis categories. M06.871 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering inflammatory polyarthropathies (m05-m14).
Under the CMS-HCC V28 risk adjustment model, M06.871 maps to Rheumatoid Arthritis and Inflammatory Connective Tissue Disease (HCC 93) with a community, non-dual, aged base RAF weight of 0.175. Under the older V24 model, M06.871 mapped to the same category but with a base RAF weight of 0.307 — 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.
This code encompasses both ankle and foot involvement on the right side; document which specific joints are affected. Because M06.871 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 M06.871 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code encompasses both ankle and foot involvement on the right side; document which specific joints are affected
- •Foot and ankle involvement in RA can significantly impact mobility; ensure functional impact is documented for treatment planning
Clinical Significance
Other specified rheumatoid arthritis of the right ankle and foot indicates an atypical RA variant affecting weight-bearing joints crucial for ambulation and balance. Involvement of these joints significantly impacts mobility, gait stability, and activities requiring standing or walking.
Documentation Requirements
- ✓Confirmed rheumatoid arthritis diagnosis with specific atypical characteristics
- ✓Physical examination documenting right ankle and/or foot joint involvement
- ✓Description of features that distinguish this as 'other specified' RA type
- ✓Assessment of ankle and foot range of motion and weight-bearing capacity
- ✓Laboratory evidence supporting active rheumatoid disease process
- ✓Functional evaluation of gait, balance, and ambulation limitations
- ✓Documentation of specific joints affected (ankle, subtalar, midfoot, forefoot)
- ✓Treatment plan including orthotic considerations when appropriate
Commonly Confused Codes
- •M06.872 — Other specified rheumatoid arthritis, left ankle and foot (incorrect laterality)
- •M06.879 — Other specified rheumatoid arthritis, unspecified ankle and foot (when laterality documented)
- •M05.871 — Other rheumatoid arthritis with rheumatoid factor of right ankle and foot (different RA classification)
- •M25.571 — Pain in right ankle (symptom code without inflammatory diagnosis)
- •M79.3 — Panniculitis, unspecified (non-articular inflammation)