Abstract: Knee joint prosthesis of the type including a first and second element (1, 2) capable of being secured rigidly to the bones connected by the joint. The first element (1) carries a clevis (3) through which the axis XX' of a bending pivot (4) passes. The second element (2) carries an eye (5) introduced between the legs of the clevis (3). The pivot (4) includes a pin (41) carrying on the outside a bearing ring (43) fitted in the eye (5) of the joint and lateral stops (44, 44') with a diameter corresponding to that of the ring (43), respectively fitted in the clevis (3).