M86.452
BillableChronic osteomyelitis with draining sinus, left femur
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M86.452 an HCC code?
Yes. M86.452 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 M86.452
For M86.452 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 M86.452 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M86.452 is the ICD-10-CM diagnosis code for chronic osteomyelitis with draining sinus, left femur. A chronic bone infection of the left thighbone (femur) that has created an open drainage channel through the skin, allowing infected material to drain continuously. M86.452 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, M86.452 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, M86.452 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 laterality is documented as 'left' in the medical record before assigning this code. Because M86.452 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 M86.452 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify laterality is documented as 'left' in the medical record before assigning this code
- •Confirm the presence of a draining sinus tract; if only chronic osteomyelitis without drainage exists, use a different M86.4x code
Clinical Significance
This diagnosis captures chronic osteomyelitis with draining sinus of the left femur, a complex condition affecting the largest bone with active drainage requiring specialized treatment. The femur's critical role in weight-bearing makes this condition particularly concerning for functional outcomes.
Documentation Requirements
- ✓Clear documentation of left femur involvement
- ✓Evidence supporting chronic nature (duration >6 weeks or recurrent)
- ✓Confirmation of active draining sinus tract from femur
- ✓Radiographic studies showing chronic osteomyelitic changes
- ✓Functional assessment of left leg and drainage status
- ✓Laboratory findings consistent with chronic infection
- ✓Treatment documentation for both infection and drainage
- ✓Clinical correlation with chronic osteomyelitis with draining sinus
Commonly Confused Codes
- •M86.552 — Other chronic hematogenous osteomyelitis, left femur, no drainage
- •M86.451 — Same condition but right-sided femur
- •M86.352 — Chronic multifocal osteomyelitis, left femur, no drainage
- •M86.152 — Acute osteomyelitis of left femur
- •L02.452 — Cutaneous abscess of left thigh, superficial infection