The angle of rotation of the knee joint during weight-bearing in osteoarthritic knees has not been fully determined. The authors aimed to examine the nature and extent of rotation during weight-bearing by means of ultrasonic investigation. There was a highly significant correlation between the rotational angle measured by ultrasound and that determined by CT. The dynamic rotatory movement during weight-bearing was measured in 107 osteoarthritic and 40 control knees. At 20 degrees of flexion the internal rotation of the early grade I osteoarthritic knees (-1.6 degrees) was significantly less than that of the control knees (-4.8 degrees, P = 0.004). This abnormality was the initial pathological rotational change in osteoarthritis of the knee joint. The external rotation at maximal extension and the rotation of the screw-home movement proportionately decreased with progression of medial compartment osteoarthritis. By virtue of these observations we have clarified the dynamic rotatory movement in osteoarthritic knees during weight-bearing.
L’angle de rotation du genou arthrosique pendant l’appui pas été entièrement expliqué. Les auteurs ont ètudié la rotation de l’articulation du genou par ultrasons. Il existe une corrélation très significative entre l’angle de rotation mesuré aux ultrasons et par tomodensitométrie. Le mouvement rotatoire dynamique pendant l’appui fut mesuré dans 107 gonarthroses et 40 genoux témoins. A une flexion de 20°, la rotation interne des genoux souffrant d’une arthrose de la classe I initiale fut significativement plus faible que celle des genoux témoins (−4.8°,P=0.004). Cette anomalie de rotation ètait la modification pathologique initiale. La rotation externe lors d’une extension maximale et la rotation du mouvement vissé a proportionnellement diminué avec la progression de l’arthrose du compartiment interne. Nous avons donc éclairci le mouvement de rotation dynamique des genous arthrosiques pendant l’appui.