Abstract: A convertible hat including a crown and a brim that can be converted between a conventional hat to a skullcap type configuration, such as a swimming cap. The brim is hingedly connected to the lower peripheral edge of the crown and protruding outwardly from the crown in an operative shading condition. The brim is retractable from the operative condition such that the brim substantially conforms to at least a portion of the outer surface of the crown.

Abstract: In order to reduce the incidence of artificial joint failure at the interface where the prosthesis is bonded to the bone by cement, the artificial prosthesis is provided with openings, and is clamped in place to provide a peripheral seal around the end of the bone to which it is being secured. Then the cement is applied through the prosthesis under pressure, and the pressure is maintained until the cement hardens. The prosthesis may be provided with both input and output openings so that, as the cement is forced into the space between the prosthesis and the cortical bone structure, material including blood and marrow contents will be forced out the exit apertures and the pressurized cement will thereafter make good direct contact with both the bone and the prosthesis, to insure a lasting bond. The rim of the prosthesis and the matching bone surfaces may be specially prepared to provide a good pressure tight seal.