M91.10 (Juvenile osteochondrosis of head of femur [Legg-Calvé-Perthes], unspecified leg) compared with M91.12 (Juvenile osteochondrosis of head of femur [Legg-Calvé-Perthes], left leg), from the official CMS tabular data. M91.10 and M91.12 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. M91.10 and M91.12 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.
| M91.10Juvenile osteochondrosis of head of femur [Legg-Calvé-Perthes], unspecified leg | M91.12Juvenile osteochondrosis of head of femur [Legg-Calvé-Perthes], left leg | |
|---|---|---|
| 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 | Juvenile osteochondrosis of head of femur [Legg-Calvé-Perthes], unspecified leg is a billable ICD-10-CM diagnosis code (M91.10). | Juvenile osteochondrosis of head of femur [Legg-Calvé-Perthes], left leg is a billable ICD-10-CM diagnosis code (M91.12). |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources