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

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.