A cadaver model to evaluate the accuracy and reproducibility of plain radiograph step and gap measurements for intra-articular fracture of the distal radius.
OBJECTIVE
The purpose of this study was to determine the accuracy and reproducibility of intra-articular step-off and gap displacements measured on plain radiographs using a standard cadaver model.


METHODS
Twenty-two physicians, in a blinded randomized fashion using a standard technique, examined the radiographs of 12 unique combinations of step and gap displacement created by a 3-part intra-articular osteotomy of the distal radius. Observer accuracy, inter- and intraobserver agreement, and tolerance limits were calculated.


RESULTS
The results of this study suggest that observers, independent of skill level, may measure step-off and gap displacements accurately to within .62 +/- .53 mm (95% confidence interval = .59-65). The accuracy of measurement was influenced by the quality of the radiograph. Intraclass correlation coefficient scores showed "substantial" (.78) to "almost perfect" (.81) inter- and intraobserver agreement.


CONCLUSIONS
These data can aid in the interpretation of clinical studies of acute distal radius fractures that are based on plain radiography.
McCallister
Wren V
WV
Department of Orthopaedics and Sports Medicine, University of Washington Medical Center, Seattle, WA 98195, USA.
Smith
Jeffery M
JM
Knight
Jeff
J
Trumble
Thomas E
TE
D002102:Cadaver; D006801:Humans; D008953:Models, Anatomic; D015588:Observer Variation; D011859:Radiography; D011885:Radius Fractures / Q000000981:diagnostic imaging*; D011897:Random Allocation; D015203:Reproducibility of Results; D012107:Research Design; D012680:Sensitivity and Specificity; D014954:Wrist Injuries / Q000000981:diagnostic imaging*