M61.171 (Myositis ossificans progressiva, right ankle) compared with M61.173 (Myositis ossificans progressiva, unspecified ankle), from the official CMS tabular data. M61.171 and M61.173 code the same condition on opposite sides. MedCoder-derived
Same condition; these differ only in which side is documented.
These codes share a category and title and differ only in the side affected. The documentation decides which applies, and a bilateral code is reported only where the code set provides one.
Source: ICD-10-CM tabular list (laterality variant derived from the code title)
Same condition, opposite side. M61.171 and M61.173 name the same condition on opposite sides of the body.
Same category and title, differing only in which side is affected — the documentation decides which one applies, and a bilateral code is reported only where the code set provides one.
| M61.171Myositis ossificans progressiva, right ankle | M61.173Myositis ossificans progressiva, unspecified ankle | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | M00-M99 — Diseases of the musculoskeletal system and connective tissue | M00-M99 — Diseases of the musculoskeletal system and connective tissue |
| Definition | Myositis ossificans progressiva, right ankle is a billable ICD-10-CM diagnosis code (M61.171). | Myositis ossificans progressiva, unspecified ankle is a billable ICD-10-CM diagnosis code (M61.173). |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources