M89.659
BillableOsteopathy after poliomyelitis, unspecified thigh
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M89.659 an HCC code?
Yes. M89.659 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 M89.659
For M89.659 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 M89.659 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M89.659 is the ICD-10-CM diagnosis code for osteopathy after poliomyelitis, unspecified thigh. Bone disease that develops as a complication of poliomyelitis affecting the thigh, but the specific side (left or right) is not documented or specified. M89.659 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, M89.659 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, M89.659 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 the medical record. Because M89.659 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 M89.659 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 the medical record
- •Query the provider if possible to obtain specific laterality information for more precise coding
Clinical Significance
Osteopathy after poliomyelitis affecting the thigh represents a chronic complication of previous polio infection, potentially causing bone deformities and functional limitations. This diagnosis is significant for risk adjustment as it indicates ongoing orthopedic complications requiring specialized care and monitoring for progression.
Documentation Requirements
- ✓Clear documentation of history of poliomyelitis infection
- ✓Evidence of osteopathy (bone disease) affecting the thigh region
- ✓Specification that laterality (right or left) is not documented or determinable
- ✓Clinical symptoms related to bone changes in the thigh area
- ✓Imaging studies showing bone abnormalities consistent with post-polio osteopathy
- ✓Documentation of functional impact on mobility or activities
- ✓Provider assessment of the relationship between current bone condition and prior polio
- ✓Evidence that this represents a sequela of poliomyelitis rather than acute condition