M23.221
BillableDerangement of posterior horn of medial meniscus due to old tear or injury, right knee
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M23.221 an HCC code?
No. M23.221 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
M23.221 is the ICD-10-CM diagnosis code for derangement of posterior horn of medial meniscus due to old tear or injury, right knee. Damage to the back portion of the inner cartilage (posterior horn of medial meniscus) of the right knee from an old tear or injury. M23.221 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering other joint disorders (m20-m25).
M23.221 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
The posterior horn is the back section of the medial meniscus; distinguish from anterior horn location.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for M23.221 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •The posterior horn is the back section of the medial meniscus; distinguish from anterior horn location
- •Verify imaging or surgical documentation clearly identifies the posterior horn location before assigning this code