M89.639
BillableOsteopathy after poliomyelitis, unspecified forearm
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M89.639 an HCC code?
Yes. M89.639 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 M89.639
For M89.639 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 M89.639 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M89.639 is the ICD-10-CM diagnosis code for osteopathy after poliomyelitis, unspecified forearm. Bone disease that develops as a long-term consequence of polio infection, affecting the forearm when the specific side is not documented. M89.639 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, M89.639 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, M89.639 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 documentation does not specify right or left side. Because M89.639 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 M89.639 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 documentation does not specify right or left side
- •Query provider if laterality can be determined from clinical context or imaging reports
Clinical Significance
Unspecified forearm post-polio osteopathy represents chronic bone changes in the radius and ulna following poliomyelitis without documented laterality, potentially indicating bilateral involvement or incomplete documentation. This affects forearm and hand function requiring comprehensive management.
Documentation Requirements
- ✓Clear history of previous poliomyelitis infection
- ✓Documentation of forearm osteopathy without side specification
- ✓Assessment for bilateral forearm involvement
- ✓Imaging studies showing post-polio bone changes
- ✓Bilateral forearm and hand functional evaluation if applicable
- ✓Pain assessment and activity limitations
- ✓Occupational therapy needs and adaptive equipment
- ✓Coordination with neurological post-polio syndrome management
Commonly Confused Codes
- •G14 — Post-polio syndrome involves neurological rather than bone pathology
- •M25.539 — Unspecified forearm pain is symptomatic only
- •S52.509A — Unspecified forearm fracture is acute injury
- •M19.039 — Primary wrist osteoarthritis is degenerative, not post-infectious
- •M87.839 — Other osteonecrosis has different pathophysiology