03/10/2026
Herring lateral pillar classification
The Herring lateral pillar classification (also known as the Herring classification) is an orthopedic system used to predict prognosis and guide treatment in Legg-Calvé-Perthes disease (idiopathic avascular necrosis of the femoral head in children)
‼️How It Works:
❇️Timing: Evaluated on an anteroposterior (AP) pelvis radiograph during the fragmentation stage of the disease (typically 6 months to 2 years after symptom onset), rather than the early/initial stage.
❇️Anatomy: The femoral head is divided into three vertical pillars at 90° to the physis:
➖Lateral pillar: ~15% to 30% of the femoral head width.
➖Central pillar: ~50% of the femoral head width.
➖Medial pillar: ~20% to 35% of the femoral head width.
‼️Classification
❇️Group A:
➖Definition: No involvement of the lateral pillar.
➖Characteristics: No loss of height or density changes in the lateral third.
➖Prognosis: Excellent; nearly always results in a spherical femoral head without severe osteoarthritis.
❇️Group B:
➖Definition: Maintained lateral pillar height is 50% or more of the original height (less than 50% loss).
➖Prognosis: Good to fair; depends heavily on the child's age at onset (younger than 6 or 8 years typically does well; older children have higher risk of deformity).
❇️B/C Border Group (added in 2004):
➖Definition: Intermediate group for border cases.
➖Characteristics: Lateral pillar is more than 50% width, but shows either a very thin width (< 2–3 mm), poor ossification, or borderline depression.
❇️Group C:
➖Definition: Maintained lateral pillar height is less than 50% of the original height (severe collapse).
➖Prognosis: Poor; carries a high risk of permanent aspherical head deformity and early-onset osteoarthritis regardless of age.
