Classification of Legg-Calvè-Perthes disease based on the height of the lateral pillar:
- Group A : No involvement of the lateral pillar with no density changes identified.
- Group B : at least 50% of the lateral pillar height maintained
- Group C: less than 50% of the lateral pillar maintained
This classification is designed to provide prognostic information.
Patients in Group A had good outcomes regardless of age.
Patients in Group B younger than 8-9 years old at onset had good outcomes, but patients older than 8-9 had less favorable results.
Patients in Group C had the worst results regardless of age at onset.
At the initial stage of the disease it is not possible to apply this classification because the patient needs to have entered into the fragmentation stage radiographically. This usually occurs 6 months after the onset of symptoms.