M61.173
BillableMyositis ossificans progressiva, unspecified ankle
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M61.173 an HCC code?
No. M61.173 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
M61.173 is the ICD-10-CM diagnosis code for myositis ossificans progressiva, unspecified ankle. A rare genetic condition where muscle tissue gradually turns into bone in the ankle area, causing progressive stiffness and loss of movement. M61.173 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering disorders of muscles (m60-m63).
M61.173 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.
Verify laterality is documented as 'unspecified' before assigning this code; if side is specified, use M61.171 (right) or M61.172 (left).
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for M61.173 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.