DISPOSITIVO/ACCOPPIATORE INFRAPOSIZIONALE PROTESICO

36 The present invention relates to a prosthetic interpositional device/coupler designed to be interposed between the neck and head of a femoral prosthesis. One example of a contemplated environment of use of the inventive interpositional device/coupler is in the situation where the prosthesis has a neck of one material and a head of another material. The inventive interpositional device/coupler may be made with an outer wall having a taper designed to match the taper of the head and with an inner wall having a taper designed to match the taper of the neck. These tapers may differ. Additionally, the inner and outer surfaces may have different surface textures from one another so as to make the respective walls compatible with the surface texture of the material of which the adjacent structure, head or neck, is made. Three embodiments of the inventive interpositional device/coupler are disclosed. The third embodiment is similar to the second embodiment except that the end wall is much thicker than the end wall in the second embodiment so that the device is greater in length than the second embodiment. The first embodiment does not include an end wall and may be shorter in length than either the second or third embodiment.