M87.071 (Idiopathic aseptic necrosis of right ankle) compared with M87.073 (Idiopathic aseptic necrosis of unspecified ankle), from the official CMS tabular data. M87.071 and M87.073 code the same condition on opposite sides.
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. M87.071 and M87.073 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.
| M87.071Idiopathic aseptic necrosis of right ankle | M87.073Idiopathic aseptic necrosis of unspecified ankle | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) | M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) |
| Definition | Idiopathic aseptic necrosis of right ankle is a billable ICD-10-CM diagnosis code (M87.071). | Idiopathic aseptic necrosis of unspecified ankle is a billable ICD-10-CM diagnosis code (M87.073). |
| Includes | avascular necrosis of bone | avascular necrosis of bone |
| Use additional code | code to identify major osseous defect, if applicable (M89.7-) | code to identify major osseous defect, if applicable (M89.7-) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources