The linea aspera-pilaster complex as a possible cause of confusion with the ‘flame sign’: a case report

Abstract

The linea aspera is an important osteological feature onto which many muscles insert. Evolutionary as well as individual lifestyle changes can lead to the radiographic appearance of the linea aspera-pilaster complex as the track sign. This rare feature is known to radiologists and anthropologists as a normal roentgen and anatomical variant. However, its knowledge is less common even amongst experienced senior orthopedic surgeons. The track sign can be readily confused with the pathological 'flame sign' of Paget's disease leading to unnecessary investigations. This case report intends to increase awareness amongst experienced and trainee orthopedic surgeons alike, of the physiological existence of the track sign.

The linea aspera as a guide for femoral rotation after tumor resection: is it directly posterior? A technical note

“…However, other radiologists, i.e., Gheorghiu and Leinenkugel [12], claimed that the “track sign” could be readily confused with the pathological “flame sign” of Paget’s disease, leading to unnecessary investigations [13]. …”

“…Radiographically, the linea aspera appears as two narrow, axially oriented, parallel lines named the “track sign” by Pitt [ 11 ] who believed it to represent the linea aspera–pilaster complex. However, other radiologists, i.e., Gheorghiu and Leinenkugel [ 12 ], claimed that the “track sign” could be readily confused with the pathological “flame sign” of Paget’s disease, leading to unnecessary investigations [ 13 ].…”

Morphological study of linea aspera variations – proposal of classification and sexual dimorphism

“…Hoeffel et al [10] assert that knowledge of the shape of the normal linea aspera is important and should not be confused with diseases such as symmetrical osteonecrosis. Also, Gheorghiu and Leinenkugel [8] noted that the "track sign" can be readily confused with the pathological "flame sign" of Paget's disease leading to unnecessary investigations. Pitt [17] concluded that normal morphological variants should be well known, especially to orthopaedic surgeons and radiologists.…”

“…While the spiral line, which provides the origin for the vastus medialis muscle, runs medially towards the lesser trochanter, the pectineal line, marking the insertion of the pectineus muscle, is located lateral and superior to it [15]. Contrary to this morphological definition, the clinical definition is short, because the linea aspera consists of two axially oriented parallel lines superimposed on the middle third of the posterior surface of the shaft [5,8,10,17]. However, according to our observations, the shape of the linea aspera is much more varied and so it is necessary to describe this structure more precisely.…”

“…However, according to our observations, the shape of the linea aspera is much more varied and so it is necessary to describe this structure more precisely. Such knowledge may be useful in clinical practice, especially in Radiology and Orthopaedy [3,7,8,17].…”