M87.234
BillableOsteonecrosis due to previous trauma of right ulna
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M87.234 an HCC code?
Yes. M87.234 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 M87.234
For M87.234 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 M87.234 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M87.234 is the ICD-10-CM diagnosis code for osteonecrosis due to previous trauma of right ulna. Death of bone tissue in the right forearm bone (ulna) resulting from a previous injury. M87.234 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, M87.234 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, M87.234 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.
The ulna is the medial bone of the forearm; distinguish from radius codes (M87.231-233). Because M87.234 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 M87.234 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •The ulna is the medial bone of the forearm; distinguish from radius codes (M87.231-233)
- •Document the history of trauma that led to this osteonecrosis
Clinical Significance
Right ulna osteonecrosis following trauma represents a serious complication affecting forearm stability and rotation. This condition can significantly impact hand and wrist function, often requiring surgical intervention and long-term orthopedic management to prevent further deterioration.
Documentation Requirements
- ✓Documentation of previous trauma specifically to the right ulna
- ✓Imaging evidence demonstrating osteonecrosis of right ulna bone
- ✓Clinical examination findings consistent with ulnar dysfunction
- ✓Exclusion of other causes of osteonecrosis (steroids, alcohol, radiation)
- ✓Documentation of pain, weakness, or functional limitations
- ✓Provider statement establishing causal relationship with trauma
- ✓Timeline connecting previous injury to current necrotic process
- ✓Assessment of impact on forearm pronation/supination
Commonly Confused Codes
- •M87.034 — Idiopathic osteonecrosis of right ulna (no traumatic cause)
- •S52.601A — Unspecified fracture of lower end of right ulna (acute trauma)
- •M86.034 — Acute hematogenous osteomyelitis of right ulna (infection)
- •M87.334 — Other secondary osteonecrosis of right ulna (non-traumatic secondary)
- •M25.521 — Pain in right elbow (symptom only)