Legg-Calve-Perthes Disease in Emergency Medicine Workup

Updated: Mar 03, 2018
  • Author: Jessica Hernandez, MD; Chief Editor: Trevor John Mills, MD, MPH  more...
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Workup

Imaging Studies

Radiography

Plain radiographs of the hip, including anteroposterior and frog-leg views, are the preferred diagnostic tests. These are extremely useful in establishing the diagnosis. (Several radiographs are shown below.)

Legg-Calvé-Perthes disease. Image shows subchondra Legg-Calvé-Perthes disease. Image shows subchondral sclerosis and radiolucency in the left femoral head (stage II disease). The femoral head is slightly smaller on the left than the right.
Legg-Calvé-Perthes disease. The left subchondral r Legg-Calvé-Perthes disease. The left subchondral radiolucency is more readily demonstrated on a frog-leg view and represents subchondral fracture.
Legg-Calvé-Perthes disease. Image shows left femor Legg-Calvé-Perthes disease. Image shows left femoral subchondral sclerosis and radiolucency.
Legg-Calvé-Perthes disease. Image shows flattening Legg-Calvé-Perthes disease. Image shows flattening and early fragmentation of the left femoral head with the presence of femoral neck cysts. The femoral head is obviously smaller on the left than on the right.

Multiple radiographic classification systems exist, [12] based on the extent of abnormality of the capital femoral epiphysis. Waldenstrom, [13] Catterall, [3] Salter and Thompson, and Herring are the 4 most common classification systems. No agreement has been reached as to the best classification system.

Five radiographic stages can be seen by plain radiography. In sequence, they are as follows:

  • Cessation of growth at the capital femoral epiphysis; smaller femoral head epiphysis and widening of articular space on affected side

  • Subchondral fracture; linear radiolucency within the femoral head epiphysis

  • Resorption of bone

  • Reossification of new bone

  • Healed stage

Other imaging studies

Technetium Tc-99m bone scanning can be used to detect early disease or define the extent of ischemia, as well as to predict severity. Currently, this type of study is not in high use because of radiation exposure and the lack of anatomic detail of the femoral head and its relationship to the acetabular fibrocartilage. [19]

Dynamic arthrography can provide early information by assessing the degree of flattening and amount of cartilaginous extrusion; however, it remains an invasive procedure and is difficult to repeat. [19]

A review of the literature has proposed MRI as a valuable modality to evaluate Legg-Calvé-Perthes disease, [20] especially with the use of newer sequences such as delayed gadolinium enhancement (to depict cartilage) and diffusion-weighted sequences (to assess cartilage repair). [19] However, under current American College of Radiology guidelines, MRI evaluation is not the initial test of choice. [21, 22, 23, 5]

An example of an MRI depicting Legg-Calvé-Perthes disease is shown below.

Legg-Calvé-Perthes disease. Coronal T1-weighted im Legg-Calvé-Perthes disease. Coronal T1-weighted image demonstrates irregularity and distortion of the right femoral head in this 7-year-old child with known Legg-Calvé-Perthes disease. Image courtesy of Radiopaedia.org, contributed by Dr. Roberto Schubert, published at http://radiopaedia.org/cases/legg-calve-perthes-disease-4.

Ultrasonography is less helpful for the diagnosis of Legg-Calvé-Perthes disease because it provides limited evaluation of osseous structures; however, it may be used to evaluate for effusion.