Subcategory M92.5, Juvenile osteochondrosis of tibia and fibula, has been expanded to distinguish juvenile osteochondrosis of different parts of the tibia and fibula as follows:
- Unspecified juvenile osteochondrosis (M92.50-)
- Juvenile osteochondrosis of proximal tibia (M92.51-)
- Juvenile osteochondrosis of tibia tubercle (M92.52-)
- Other juvenile osteochondrosis of tibia and fibula (M92.59-)
The code expansion will help to distinguish Blount disease and Osgood-Schlatter disease. These are two very distinct conditions both in character, prognosis and treatment.
Blount disease (M92.51-) is a growth disorder of the tibia (shin bone) resulting in bowlegged appearance. The disease causes the growth plate near the inside of the knee to either slow down or stop making new bone, while the growth plate near the outside of the knee continues to grow normally. Some children may also experience pain and instability of the knee. This condition occurs in growing children. Infantile Blount’s disease generally occurs as bilateral deformity only in the tibia (shin bone). Adolescent Blount’s disease occurs in children over 10 years of age and is more likely to be unilateral typically affecting both the femur and the tibia.
Osgood-Schlatter disease (M92.52-) occurs in adolescence and is characterized by a painful bump just below the knee that is worse with activity and better with rest. Soreness and swelling at the tibial tuberosity is also common. It usually occurs in children and adolescents during puberty, and most often in children who participate in sports that involve running, jumping and swift changes of direction.