Razi Journal of Medical Sciences

    Background & Aim: In radiographic evaluation of carpal instability, the standard method has been the measurement of a series of angles and the new triangulation ratio on lateral wrist radiograms. This study was undertaken to compare these indices in normal and unstable joints. Patients and Methods: Nineteen normal wrist radiograms along with 21 with plamar and 19 with dorsal instability patterns, taken in true lateral position, were enrolled in the study. In each radiogram six variants were measured: capitolunate, radiolunate, radiocapitate, scapholunate and radioscaphoid angles and the triangulation ratio. Results: Between the palmar and normal groups the difference between radiolunate and capitolunate angles and the triangulation ratio, and also between the dorsal and normal groups the difference between the radiolunate and scapholunate angles and the triangulation ratio was statistically significant. In addition, there was no discrete border between normal and abnormal angles. Conclusion: According to these results, it seems that the measure of these angles in itself is not adequate proof for instability of the wrist however among the indices, radiolunate angle and triangulation ratio are more precise than the others.