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Legg-Calvé-Perthes disease

Legg-Calvé-Perthes disease (LCPD) (more frequently simply referred to as Perthes disease) is idiopathic avascular necrosis (AVN) of the growing femoral epiphysis seen in children, and should not be confused with the Perthes lesion of the shoulder.


Typically, LCPD is seen between the ages of 4-8 years 3,5-6.

Clinical presentation

The most frequent presenting feature is pain with or without a limp 3,5-6. In 10-12 % of cases both hips are involved 5.

Radiographic features

The radiographic findings are those of AVN.

Plain film
Early signs
  • asymmetrical femoral epiphyseal size (smaller on affected side)
  • apparent increased density of the femoral head epiphysis
  • widening of the medial joint space
  • blurring of the physeal plate (stage 1: see staging of Legg-Calve-Perthes syndrome)
  • radiolucency of the proximal metaphysis
Late signs

Eventually, the femoral head begins to fragment (stage 2), with subchondral lucency (crescent sign) and redistribution of weight-bearing stresses leading to thickening of some trabeculae which become more prominent.

The typical findings of advanced burnt out (stage 4) Perthes disease are:

  • femoral head deformity with widening and flattening
  • proximal femoral neck deformity

Additionally, tongues of cartilage sometimes extend inferolaterally into the the femoral neck, creating lucencies, which must be distinguished from infection or neoplastic lesions 4. The presence of metaphyseal involvement no only increases the likelihood of femoral neck deformity, but also make early physeal closure with result leg length disparity more likely.


Traditionally arthrography performed under general anaesthesia with conventional fluoroscopy is performed to assess congruency between the femoral head and the acetabulum in a variety of positions 3. MRI is increasingly replacing this, in an effort to eliminate pelvic irradiation.


MRI is gaining an increasing role in a number of scenarios:

  • early diagnosis, before the onset of x-ray findings, and in designing 
  • assessing extent of cartilaginous involvement, important in prognosis
  • assessing joint congruency in a variety of joint positions (requires open magnet and dynamic imaging) 2

Both arthrography and dynamic MRI asses three main features 3:

  1. deformity for the femoral head (also assessed on static x rays and MRI)
  2. congruency - how well the femoral head contour matches that of the acetabulum
  3. containment - the amount of lateral subluxation of the flattened femoral head out of the acetabulum. When severe this may lead to hinge abduction, whereby rather than rotation and medial movement of the femoral head during hip abduction, the flattened head 'hinges' on the lateral lip of the acetabulum, widening the medial joint space 2-3.

Treatment and prognosis

Prognosis is influenced primarily by the degree of primary deformity of the femoral head and the secondary osteoarthritic changes that ensue. The aim of therapy is to try and maintain good femoroacetabular contact and a round femoral head. 

Bracing may be used in milder cases, although femoral neck and acetabular osteotomies may be required to correct more sever abnormal femoroacetabular malalignment.

In later life, hip replacements may be necessary.


The condition was first described in 1897 by Maydl, with Legg, Calvé and Perthes popularising it in 1910 in separate publications 7.

  • Karel Maydl (1853 - 1903) : Austrian surgeon
  • Aurthur Thornton Legg (1874 - 1939) : American orthopaedic surgeon
  • Jacques Calvé (1875 - 1954) : French orthopaedic surgeon
  • Gerog Clemens Perthes (1869 - 1927) : German surgeon

Differential diagnosis

General imaging differential considerations include

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