Usefulness and reliability of two- and three-dimensional computed tomography in patients older than 65 years with distal humerus fractures.
BACKGROUND
Distal humerus fractures are difficult to characterise and to classify according to the AO system. In this multicentre study, our objectives were to assess the usefulness of computed tomography (CT) and to measure intra-observer and inter-observer reliability according to observer experience.


METHODS
An online survey of professional practice was performed using a questionnaire based on a clinical case. Participants were asked to determine the AO classification using radiographs then to reappraise their answers after the addition of CT images. For the reliability study, 16 observers in five centres evaluated radiographs and CT scans of 26 distal humerus fractures. They used the radiographs to determine the AO classification and assess the main fracture characteristics then reappraised their findings after adding the CT images. The radiographs and 2D CT images were read twice at an interval of 2 weeks, and during the second reading, 3D CT images were available also. At least 1 month later, the same observers performed similar readings 2 weeks apart (radiographs and 2D CT images at the first reading and addition of 3D CT images at the second reading).


RESULTS
Correct fracture classification was achieved in 95% of cases with the CT images compared to only 73% with the radiographs. CT led to diagnostic and therapeutic changes in 90% and 25% of cases, respectively. Inter-observer reliability was poor for both AO classification and fracture characteristics, not only with the radiographs and 2D CT images, but also with the added 3D CT images. In contrast, intra-observer reliability improved after the addition of 3D CT images. Assessment accuracy was influenced by image quality and geographic origin of the observer but not by observer experience.


CONCLUSIONS
CT improves diagnostic accuracy and, in some cases, changes the surgical strategy. In our study of a large number of observers, CT did not improve inter-observer agreement about the study variables. Intra-observer agreement was improved by 3D CT but not by 2D CT. Accuracy was not influenced by years of observer experience but was dependent on image quality, proficiency with computer-based tools and, above all, image observation and interpretation.


METHODS
Level III.
Service d'orthopédie-traumatologie, centre chirurgical E.-Galle, 49, rue Hermite, 54000 Nancy, France.
A
A
Jacquot
Service d'orthopédie-traumatologie, place Amélie-Raba-Leon, 33076 Bordeaux cedex, France.
N
N
Poussange
Département d'orthopédie-traumatologie, CHU Dupuytren, 2, avenue Martin-Luther-King, 87042 Limoges cedex, France.
J-L
JL
Charrissoux
Centre de chirurgie orthopédique et de la main, 10, avenue Achille-Baumann, 67400 IllkirchGraffenstaden, France.
P
P
Clavert
Chirurgie orthopédique, traumatologique et plastique, centre hospitalier de Besançon, 2, boulevard Fleming, 25030 Besançon, France.
L
L
Obert
Service de traumatologie, chirurgie orthopédique, centre hospitalier, 194, avenue Rubillard, 72037 Le Mans, France.
L
L
Pidhorz
Service d'orthopédie-traumatologie, centre chirurgical E.-Galle, 49, rue Hermite, 54000 Nancy, France.
F
F
Sirveaux
Service de traumatologie, chirurgie orthopédique, centre hospitalier, 194, avenue Rubillard, 72037 Le Mans, France; Institut de l'appareil locomoteur, CHU de Toulouse, place du Dr-Baylac, 31059 Toulouse, France.
P
P
Mansat
Service d'orthopédie-traumatologie, place Amélie-Raba-Leon, 33076 Bordeaux cedex, France. Electronic address: thierry.fabre@chu-bordeaux.fr.
T
T
Fabre
D000368:Aged; D005260:Female; D006801:Humans; D006810:Humeral Fractures / Q000000981:diagnostic imaging*; D021621:Imaging, Three-Dimensional; D008297:Male; D012372:ROC Curve; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*
Computed tomography; Distal humeral fracture; Inter-observer reliability