Abstract: A modular prosthesis attachment mechanism which uses a special bolt that provides an attachment position that is not directly over the hole or recess used to capture the head of the bolt. Thus, the attachment mechanism can be used with one location hole on a prosthesis and provide multiple augmentation locations just by offering multiple bolts with varying offsets. The use of a washer-like support may also be required to help redistribute the forces associated with the new attachment location. Thus, the invention is beneficial in knee replacement surgery requiring augmentation pieces. By providing the surgeon with a number of options to best place each piece, such as a stem, this mechanism can be helpful in meeting the needs of individual patients.