Abstract: This invention describes a femoral twin-stem for a hip endoprosthesis. The ateral stem portion and the medial stem portion are connected by a bridge. The neck of the femoral twin-stem is connected to the proximal section of the lateral stem portion. The proximal prong of the medial stem portion and the distal prong of the lateral stem portion allow for a gradual load transfer to the bone since they can be individually designed with a proper geometry all the way to their respective tips. Gradual load transfer in turn reduces stresses in the bone cement mantle and improves the long term results of the hip replacement effected with this femoral twin-stem.

Abstract: A method of preparing a self-curing two-component cement, which is particularly useful for the preparation of bone cement used in orthopedics, from a powder component and a liquid component. The method includes providing the powder component in a first at least partially evacuated inflexible container, providing the liquid component in a second inflexible container, and adding the liquid component to the evacuated powder component, such that the liquid floods the evacuated interspaces between the powder particles. An apparatus for carrying out this process is a syringe with a slidable piston, the syringe being sealed at its dispensing end by a removable plug. Preferably, the syringe is fitted with an axially collapsible spiral mixing device, one end of which is an elongated shaft which extends through the removable plug at the dispensing end. The elongated shaft can be rotated to homogenize the contents of the syringe, but during dispensing the mixing device collapses as the piston advances.