M02.161
BillablePostdysenteric arthropathy, right knee
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M02.161 an HCC code?
Yes. M02.161 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 M02.161
For M02.161to 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 M02.161 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M02.161 is the ICD-10-CM diagnosis code for postdysenteric arthropathy, right knee. Joint inflammation and pain in the right knee that develops after a dysentery infection (severe diarrheal illness). M02.161 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, M02.161 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, M02.161 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.
Confirm right knee is specifically documented as the affected joint site. Because M02.161 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 M02.161 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm right knee is specifically documented as the affected joint site
- •This reactive arthropathy typically occurs weeks after the initial dysentery infection
Clinical Significance
Postdysenteric arthropathy of the right knee represents a chronic reactive arthritis that can significantly impair mobility, weight-bearing, and functional independence. This condition develops following dysentery infection and requires ongoing management due to its inflammatory nature and potential for progressive joint damage.
Documentation Requirements
- ✓History of dysentery or severe infectious diarrheal illness
- ✓Right knee joint involvement specifically documented
- ✓Evidence of knee arthropathy (swelling, pain, stiffness, instability)
- ✓Temporal relationship between infection and knee symptoms
- ✓Chronic or persistent nature of joint inflammation
- ✓Functional assessment of mobility and ambulation
- ✓Physical examination findings consistent with knee arthritis
Commonly Confused Codes
- •M02.162 — Postdysenteric arthropathy, left knee (opposite laterality)
- •M02.169 — Postdysenteric arthropathy, unspecified knee (when side not specified)
- •M00.061 — Staphylococcal arthritis, right knee (direct infection, not reactive)
- •M17.11 — Unilateral primary osteoarthritis, right knee (degenerative disease)
- •M23.91 — Unspecified internal derangement of right knee (mechanical problem)