M86.551
BillableOther chronic hematogenous osteomyelitis, right femur
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M86.551 an HCC code?
Yes. M86.551 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 M86.551
For M86.551 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 M86.551 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M86.551 is the ICD-10-CM diagnosis code for other chronic hematogenous osteomyelitis, right femur. A chronic bone infection of the right thighbone (femur) that developed from bacteria spreading through the bloodstream. M86.551 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, M86.551 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, M86.551 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 femur is documented; this is a common site for hematogenous osteomyelitis. Because M86.551 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 M86.551 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm right femur is documented; this is a common site for hematogenous osteomyelitis
- •Do not use this code if the infection is in the left femur or if laterality is unspecified
Clinical Significance
Chronic hematogenous osteomyelitis of the right femur represents one of the most serious bone infections due to the femur's weight-bearing function and rich vascular supply. This condition often requires prolonged antibiotic therapy and may necessitate surgical intervention, significantly impacting patient mobility and quality of life.
Documentation Requirements
- ✓Documentation of chronic duration (>6 weeks or recurrent episodes)
- ✓Evidence of hematogenous spread from bloodstream source
- ✓Specific involvement of right femur bone
- ✓Radiographic evidence of bone infection (X-ray, MRI, bone scan)
- ✓Laboratory confirmation (elevated ESR, CRP, positive cultures when available)
- ✓Assessment of functional impairment and mobility limitations
- ✓Documentation of treatment response and complications
- ✓Differentiation from post-traumatic or contiguous spread osteomyelitis
Commonly Confused Codes
- •M86.552 — Other chronic hematogenous osteomyelitis, left femur (opposite side)
- •M86.651 — Other chronic osteomyelitis, right thigh (non-hematogenous origin)
- •M86.451 — Chronic osteomyelitis with draining sinus, right femur (has sinus tract)
- •M86.151 — Other acute osteomyelitis, right femur (acute phase)
- •M87.051 — Idiopathic aseptic necrosis of right femur (avascular necrosis, not infection)