M89.661
BillableOsteopathy after poliomyelitis, right lower leg
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M89.661 an HCC code?
Yes. M89.661 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 M89.661
For M89.661 to 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 M89.661 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M89.661 is the ICD-10-CM diagnosis code for osteopathy after poliomyelitis, right lower leg. Bone disease that develops as a complication of poliomyelitis affecting the right lower leg, causing weakening or deformity of the bone in that area. M89.661 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, M89.661 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, M89.661 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 the patient has a documented history of poliomyelitis to justify the 'after poliomyelitis' designation. Because M89.661 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 M89.661 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm the patient has a documented history of poliomyelitis to justify the 'after poliomyelitis' designation
- •The fifth character '1' indicates right side; ensure this matches the clinical documentation
Clinical Significance
Right lower leg osteopathy after poliomyelitis represents a chronic bone complication from previous polio infection, potentially causing deformities and functional impairment. This diagnosis has important risk adjustment implications as it indicates ongoing orthopedic complications requiring specialized management and monitoring.
Documentation Requirements
- ✓Documentation of previous poliomyelitis infection
- ✓Evidence of osteopathy specifically affecting the right lower leg
- ✓Clinical presentation of bone changes, deformities, or functional limitations
- ✓Imaging studies confirming bone abnormalities in the right lower leg
- ✓Provider assessment linking current bone condition to prior polio infection
- ✓Documentation of impact on ambulation or lower extremity function
- ✓Evidence that this represents a sequela rather than acute condition
- ✓Assessment of progression or stability of bone changes