Knee-joint endoprostheses

In a knee-joint endoprosthesis, consisting of a lower tibia section to be anchored in the shin-bone by a lower shank, which section has, on either side of a central ridge which extends from front to rear, a bearing face which rises in a curve towards the front and which is hollowed-out in cross-section, and of a femur section which is to be anchored in the thigh-bone by an upper shank and which is provided with two pads which are yoked together across the ridge and are supported on the bearing faces, the improvement which consists in that a saddle-shaped ridge is provided with a fixed guiding cross-shaft which forms a free spigot on either side of said ridge and which lies off and to the rear of the centre axis of said lower shank when the joint is in the extended position, in that said two curved, hollowed-out bearing faces, and said supporting pads, which conform to said bearing faces in the extended position, diminish in width from front to rear as a result of said ridge becoming wider in the rearward direction, in that said spigots engage with clearance in guide grooves in said supporting pads which extend approximately parallel to the lower faces of said pads and which open upwards at their rear ends, and in that the extension of the two sections of the joint is restricted by an abutment.