The John Thomas sign is a favourite of medical students and theorizes that in femoral neck fractures, the male member will lie to the side of the fracture on the plain radiograph. The aim of this study was to evaluate the accuracy, and examine the phenomenon of eponymous signs. We sought to answer the following questions: (1) How accurate is the sign in the context of a consecutive series of male patients with hip fractures? (2) Is there a relationship between side and size of penile lie and the side of fracture?
That the accuracy of the John Thomas sign is, like many eponymous signs, spurious.
Materials and methods
Two hundred male AP pelvis radiographs were examined, of which 100 had a hip fracture and compared these against 100 control films that did not. Age at presentation, and the side, length and angle of penile lie were measured.
The results show two findings: that the accuracy of the supposed “sign” is less accurate than the toss of a coin; and that left lie and left-sided fractures are more common. We fail to show a relationship between side of fracture, John Thomas size or degree of angulation.
John Thomas sign is no better than the toss of a coin in relation to hip fractures, and is not related to side of fracture, or penile attitude. We propose that the side of lie observed in male fractures may be as a result of handedness or natural underlying body asymmetry rather than as a result of the fracture.
Level of evidence
Level III Case control study.Le texte complet de cet article est disponible en PDF.
Keywords : Hip fracture, Radiology, Medical education, Trauma, Eponymous signs, Medical heuristics
|☆|| The subject of the following article is, to say the least, unusual, but the Editorial Board has decided to make room for it nonetheless. It can be read humoristically, as tongue-in-cheek or an April Fool's Day spoof. Or it can be seen as a high-quality methodological approach to a topic of no real interest, raising a genuine question: is the methodological quality of a study enough to merit its publication?
In the present case, the answer pretty clearly seems to be No! We are including it all the same – perhaps just to stimulate reflection on the part of editors, reviewers and authors as to the experimental or clinical relevance of the studies we wish to publish.