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Classification of Perthe's disease

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

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Classification of Perthe's disease

A fourfold classification of the condition in relation to extent of the involvement of the femoral head has been proposed by Catterall:

  • grades of involvement are as follows:
    • I - central involvement
    • II - central involvement with collapse
    • III - nearly whole head involvement
    • IV - whole head involvement

  • but the reliability and prognostic value is limited (1)
  • this classification was supplemented with “head at risk signs”
    • these were associated with a poorer prognosis
    • signs include:
      • Gage's sign - a radiolucent defect between the lateral epiphysis and metaphysis
      • calcification lateral to the epiphysis
      • metaphyseal cysts
      • lateral subluxation
      • horizontal growth plate (2)

An alternative classification based on the height of the lateral pillar of the epiphysis of the femoral head (as seen on an AP x-ray view) in the early fragmentation phase has been described by Herrring in 1992.

  • the three choices include:
    • the lateral pillar is intact
    • at least 50% of the lateral pillar remains standing
    • less than 50% of the lateral pillar remains standing (1)

  • this has a greater prognositic value and also a greater inter-observer reliability than the Catterall classification
  • predictive value is higher when the patient's age at the onset of the disease is also taken into consideration (1).


  1. Nelitz M, Lippacher S, Krauspe R, Reichel H. Perthes Disease Current Principles of Diagnosis and Treatment Dtsch Arztebl Int. 2009 July; 106(31-32): 517–523.
  2. The Pediatric Orthopaedic Society of North America (POSNA) 2012. Legg-Calve-Perthes Syndrome

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