M02.179
BillablePostdysenteric arthropathy, unspecified ankle and foot
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M02.179 an HCC code?
Yes. M02.179 maps to Bone/Joint/Muscle Infections/Necrosis under the CMS-HCC V28 risk adjustment model (and Bone/Joint/Muscle Infections/Necrosis 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 M02.179
For M02.179to 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 M02.179 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M02.179 is the ICD-10-CM diagnosis code for postdysenteric arthropathy, unspecified ankle and foot. Joint inflammation in the ankle and foot following dysentery infection when the specific side (left or right) is not documented or is bilateral. M02.179 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering infectious arthropathies (m00-m02).
Under the CMS-HCC V28 risk adjustment model, M02.179 maps to Bone/Joint/Muscle Infections/Necrosis (HCC 92) with a community, non-dual, aged base RAF weight of 0.209. Under the older V24 model, M02.179 mapped to the same category but with a base RAF weight of 0.482 — 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.
Use this code only when laterality cannot be determined from documentation. Because M02.179 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 M02.179 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when laterality cannot be determined from documentation
- •Query the provider if laterality is documented elsewhere in the medical record
Clinical Significance
Postdysenteric arthropathy affecting the ankle and foot without specified laterality represents a chronic reactive arthritis that significantly impacts weight-bearing and ambulation. Despite unspecified laterality, this condition requires comprehensive management due to the critical role of ankle/foot function in mobility and daily activities.
Documentation Requirements
- ✓History of dysentery or infectious diarrheal illness documented
- ✓Ankle and foot involvement without laterality specification
- ✓Evidence of arthropathy symptoms affecting ankle/foot function
- ✓Post-infectious temporal relationship established
- ✓Chronic or persistent nature of joint inflammation
- ✓Ambulation and weight-bearing assessment
- ✓Physical findings consistent with ankle/foot arthritis
Commonly Confused Codes
- •M02.171 — Postdysenteric arthropathy, right ankle and foot (use when right side documented)
- •M02.172 — Postdysenteric arthropathy, left ankle and foot (use when left side documented)
- •M02.169 — Postdysenteric arthropathy, unspecified knee (different joint location)
- •M00.079 — Staphylococcal arthritis, unspecified ankle and foot (septic arthritis)
- •M25.579 — Pain in unspecified ankle and joints of unspecified foot (symptom)