Legg, Calvé, and Perthes separately, but at about the same time in 1910, used the newly discovered roentgen ray to identify a new disease characterized by progressive femoral head deformity in children. Legg had observed five cases, Calvé ten, and Perthes six. However, in his paper, Über Arthritis deformans juvenalis, Perthes notes Karel Maydl had originally reported the first cases in 1897.1 Perthes further describes in his 1910 report that 32 cases other than his own six had been described, with 12 involving both hips. However, it is questionable whether most of these cases represent what we now know as Legg-Calvé- Perthes disease. The two cases reported by Maydl were patients ages 15 (girl) and 18 (boy). The histories of hip problems in both were recent and Maydl reported no past history in either patient (the histories were very brief); neither had roentgenograms. In 1895 resection arthroplas- ties were performed in both cases and cross-sections of the femoral heads revealed substantial destruction and osteophyte formation completely unlike that seen as later residuals in Legg-Calvé-Perthes disease. These cases likely reflect low grade chronic infection. Of the 38 cases Perthes lists in a table of all cases, only nine were under 10 years old, and some patients were in their 20s and 30s. Perthes provides roentgenograms of four of his cases, and these likely represent the entity, but line drawings of the other two have such deformity they likely represented infection with septic necrosis.
In fact, Legg, Calvé, and Perthes originally all believed that the condition, now called Legg-Calvé-Perthes disease, was somehow associated with infection, particularly tuberculosis which, in the early 20th century, was still a common affliction in childhood. Although the condition is known by their names, by the time they had published these papers, they had made the distinction between infection and “arthritis deformans juvenalis.” These three Classic Articles illustrate how Roentgen's new diagnostic modality helped orthopaedic surgeons differentiate infection from other musculoskeletal conditions.