Quantitative assessment of femoral head involvement in Legg-Calvé-Perthes disease.

We have developed a method for determining the extent of avascularity of the capital femoral epiphysis in suspected Legg-Calvé-Perthes disease. The avascularity is expressed quantitatively as a percentage of the normal uptake of a radionuclide in the vicinity of the involved hip. In twenty-seven patients who had radionuclide scintigraphy this method was reliable in establishing an early diagnosis of Legg-Calvé-Perthes disease as well as in assessing the amount of involvement of the femoral head. In some patients the diagnosis can be established by radionuclide scintigraphy before the changes of Legg-Calvé-Perthes disease are apparent on standard radiographs.