Résumé
Objective To explore the impact of maximal movement on the stabilization of the four corner arthrodesis.Methods Flexion,extension,ulnar deviation and radial deviation movements were simulated on the wrists of 21 fresh cadaver fore-arm specimens.Maximal movements were performed in each of the four directions. Firstly,anteroposterior view and lateral view photos were taken before and after movement in each direction.Sec- ondly,capito-lunate angle,radio-lunate angle,captio-lunate posteroantefior angle,the height and width of the syzygium were measured before and after movement in each direction.The wrist before each kind of movement was used as the control for itself after the movement in the test.Results Compared with the control data,the differ- ences in capito-lunate angle,radio-lunate angle and the height of the syzygium were statistical significant before and after movement in the direction of flexion 40?and extension 30?(P＜0.05).Moreover,the differences in the captio-lunate posteroanterior angle and the width of the syzygium were also statistical significant before and after movement in radial deviation 15?and ulnar deviation 20?(P＜0.01).Maximal movements at other positions had little impact on the stability of the arthrodesis.Conclusion It is safe to perform high intensity movements to the four-comer syzygium when the range of motion is not beyond flexion 40?,extension 30?,ulnar deviation 20?and radial deviation 15?.Cireumduction should be avoided.