Question 1

What is ICD-10 code M23.331?

Accepted Answer

M23.331 is the ICD-10-CM diagnosis code for other meniscus derangements, other medial meniscus, right knee. Damage or displacement of another part of the inner meniscus in the right knee, not including the anterior or posterior horn. M23.331 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).

M23.331 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.

This code is used when the meniscus damage involves areas other than the anterior or posterior horn (such as the body or periphery).

Question 2

Is M23.331 an HCC code?

Accepted Answer

No. M23.331 is a billable ICD-10-CM code but does not map to any payment HCC category under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can still be reported on Medicare Advantage encounter data submissions, but it does not contribute to the beneficiary's Risk Adjustment Factor (RAF) score and therefore does not affect the risk-adjusted capitation payment to the plan. V28 reached 100% phase-in for payment year 2026.

Question 3

Is M23.331 billable?

Accepted Answer

Yes. M23.331 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. M23.331 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Question 4

What is the V28 vs V24 difference for M23.331?

Accepted Answer

M23.331 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither model rewards M23.331 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

Question 5

What should coders know when reporting M23.331?

Accepted Answer

This code is used when the meniscus damage involves areas other than the anterior or posterior horn (such as the body or periphery) Ensure the documentation specifies the medial meniscus and right knee to support this code

M23.331

Is M23.331 an HCC code?

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