Classically, Blount disease has been described as two distinct forms: early or infantile Blount disease and late or adolescent Blount disease. Infantile Blount disease is diagnosed at age 1-3 years, presenting when a child begins to ambulate. Infantile Blount disease is less commonly associated with obesity and is often bilateral.

Late-onset Blount disease has been further subcategorized into juvenile, occurring at age 4-10 years, and adolescent, occurring at older than 10 years. Blount disease occurring in older children is more commonly seen associated with obesity and is more often unilateral.

Langenskiold classification is used to assess severity of Blount disease depending on age and degree of depression of the medial plateau.

Findings are consistent with late onset adolescent Blount's disease