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° ± 1.8° for the distal radius articular angle; 1.2° ± 3.8° for the radiolunate angle; 54.2° ± 5.6° for the radioscaphoid angle; 1.9° ± 2.2° for the radiocapitate angle; –1.0° ± 2.5° for the radius-third metacarpal angle; 52.9° ± 6.9° for the scapholunate angle; 0.7° ± 4.1° for the lunocapitate angle; –2.3° ± 4.6° 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. Type of study/level of evidence Diagnostic II.