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.
Department of Orthopaedics and Sports Medicine, University of Washington Medical Center, Seattle, WA 98195, USA.
Wren V
WV
McCallister
Jeffery M
JM
Smith
Jeff
J
Knight
Thomas E
TE
Trumble
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*