Wrist motion analysis in scaphoid nonunion

The motion of human wrist is a complex and multidirectional process. The aim of this study was to develop a reliable and practicable method to measure motion impairment of the wrist in patients who incurred a scaphoid nonunion. A scaphoid nonunion in computed tomography as well as the consent in this study was required.

A total of nine patients with unilateral scaphoid nonunion accomplished maximal circumferential wrist movements. The wrist movements were measured with an electrogoniometer (Biometrics Ltd.). To quantify maximal wrist motion we constructed the maximal boundaries of the wrist motion from angular plots in flexion-extension (FE) and radio-ulnar deviation (RUD). We calculated the area of the circumduction envelope, the ranges of motion in FE and RUD and the main axis in wrist motion (dart-throwin-motion). The collected data were reconstructed with a custom-made MatLab program. We compared the impaired with the unimpaired side of each patient and analyzed with student's t test.

A scaphoid nonunion significantly reduced motion ranges in flexion/extension but not in ulnar and radial deviation. The overall mobility as quantified by the area of the circumduction envelope, decreased significantly. The circumduction boundaries of the wrists showed a kidney-shaped configuration with an oblique axis from radial/extension to ulnar/flexion.

Our results demonstrate that scaphoid nonunion without pain has motion deficits and may be poorly quantified with conventional manual goniometers.