M91.1 is a "category code," which means it's non-billable. Billable codes require more specificity. Use the list below to navigate to codes that are more specific:
10
M91.10
Juvenile osteochondrosis of head of femur [Legg-Calvé-Perthes], unspecified leg
Billable
10
M91.11
Juvenile osteochondrosis of head of femur [Legg-Calvé-Perthes], right leg
Billable
10
M91.12
Juvenile osteochondrosis of head of femur [Legg-Calvé-Perthes], left leg
Billable