| 摘要 |
A preferred embodiment of the invention provides an accessory device which is removably applicable to a double ball-jointed fixator, to assume the relation of a cage that effectively surrounds both ball-joints of the fixator. One longitudinal end of the accessory cage quickly mounts to one bone-screw mounting member of the fixator and establishes first intersecting orthogonally related articulation axes of a first half of a dual Cardan joint, wherein such first intersection is coincident with the ball center of a first ball-joint of the fixator; the other longitudinal end of the accessory cage quickly mounts to the other bone-screw mounting member of the fixator and establishes second intersecting orthogonally related articulation axes of a second half of the dual Cardan joint, with such second intersection coincident with the ball center of the second ball-joint of the fixator. A bridle or bridge connector having spaced end connections to corresponding elements of the respective halves of the dual Cardan joint establishes a fixed spacing between the orthogonal-axis intersection points of the respective halves of the dual Cardan joint, and this fixed spacing is identical to the fixed spacing between ball centers of the double ball-jointed fixator. The releasable mounting of each half of the cage structure to its bone-screw mounting member of the fixator is a releasably clampable rotatable mount, wherein rotatability is about a longitudinal axis of the bone-screw mount of the fixator, and wherein the same longitudinal axis is aligned with the associated ball center. Individual clamp action is thus provided for independent adjustment of accessory-cage components about each of three articulation axes, for each of the halves of the dual Cardan joint.
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