M02.862
BillableOther reactive arthropathies, left knee
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M02.862 an HCC code?
Yes. M02.862 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 M02.862
For M02.862to 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 M02.862 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M02.862 is the ICD-10-CM diagnosis code for other reactive arthropathies, left knee. Joint inflammation in the left knee that develops as a reaction to an infection or other trigger elsewhere in the body. M02.862 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, M02.862 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, M02.862 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.
Verify left knee is correctly documented; reactive arthropathy can affect one or both knees. Because M02.862 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 M02.862 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify left knee is correctly documented; reactive arthropathy can affect one or both knees
- •Code the underlying infectious or systemic trigger separately to provide complete diagnosis coding
Clinical Significance
This code represents reactive arthropathy of the left knee, indicating joint inflammation triggered by a remote infectious process. Knee involvement is clinically significant due to its role in weight-bearing, mobility, and daily activities, necessitating comprehensive treatment to maintain functional capacity and prevent progression.
Documentation Requirements
- ✓Clinical evidence of left knee joint inflammation (swelling, pain, stiffness, effusion)
- ✓Documentation of reactive nature - inflammation secondary to remote infection
- ✓Specific anatomical location identified as left knee joint
- ✓Evidence ruling out direct septic arthritis or other infectious arthropathies
- ✓Documentation of triggering infection or infectious process (if identified)
- ✓Physical examination findings consistent with knee arthritis
- ✓Exclusion of other arthropathy types (rheumatoid, osteoarthritis, crystal arthropathy)
- ✓Assessment of functional limitations and mobility impact
Commonly Confused Codes
- •M00.062 — Staphylococcal arthritis of left knee (infectious vs reactive)
- •M06.062 — Rheumatoid arthritis of left knee (autoimmune vs reactive)
- •M17.12 — Unilateral primary osteoarthritis, left knee (degenerative vs reactive)
- •M02.861 — Other reactive arthropathies, right knee (laterality difference)
- •M25.562 — Pain in left knee (symptom vs specific arthropathy diagnosis)