The device has a patella integrated to an axis that is oriented perpendicular to a support element (6). The axis is introduced in a hemisphere cage of an end (7) fixed to links (3, 4) for being screwed in the support. The cage is in communication with a determined opening for permitting articulation of links at 90 degree in vertical plane and at 360 degree in horizontal plane. The end has a holding coaxially fixed to one of the links.