Measurement of Carpal Alignment Indices Using 3-Dimensional Computed Tomography

Purpose This study aimed to establish normal values for wrist carpal alignment measured by 3-dimensional computed tomography (CT) and to show the inter-and intraobserver reliability of this measurement compared with simple radiography. Methods The study utilized 3-dimensional CT and simple radiography of wrist joints in 30 asymptomatic volunteers. The wrist position was standardized using a custom-designed positioning device. Three independent observers measured carpal alignment parameters including distal radius articular angle, radiolunate angle, radioscaphoid angle, radiocapitate angle, radius-third metacarpal angle, scapholunate angle, lunocapitate angle, and lunate-third metacarpal angle. Results Based on 3-dimensional CT measurement, the mean values of these parameters were: 12.9 degrees +/- 1.8 degrees for the distal radius articular angle; 1.2 degrees +/- 3.8 degrees for the radiolunate angle; 54.2 degrees +/- 5.6 degrees for the radioscaphoid angle; 1.9 degrees +/- 2.2 degrees for the radiocapitate angle; -1.0 degrees +/- 2.5 degrees for the radius-third metacarpal angle; 52.9 degrees +/- 6.9 degrees for the scapholunate angle; 0.7 degrees +/- 4.1 degrees for the lunocapitate angle; -2.3 degrees +/- 4.6 degrees for the lunate-third metacarpal angle. All parameters showed high inter-and intraobserver reliability in the 2 modalities. Conclusions The normal values and ranges for carpal alignment angles were evaluated by using 3-dimensional CT. We could obtain high reliability in 3-dimensional CT as well as plain radiograph for the measurement of carpal alignment. Copyright (C) 2018 by the American Society for Surgery of the Hand. All rights reserved.