Harrington Arthritis Research Center

Ron Yapp

Roger H Johnson

James B Koeneman

Thomas M Hansen

Allan M Weinstein

An improved prosthesis construction in a femoral-side hip joint replacement device of the type having an elongate curved stem held within an intramedullary cavity in a femur, and a neck supporting a ball-like joint member at the femur's proximal end. The construction includes an elongate polymer core containing continuous-filament fibers oriented substantially along the length of the core. The core contains the neck, an elongate distal stem whose cross-sectional area is less than about one-quarter that of the neck, and a tapered sections which mates the neck to the stem. A polymer skin fused to and covering the stem and tapered section of the core is shaped and dimensioned to conform to and fill the bone cavity. A braided sheath encases the stem and tapered sections of the core and it embedded in the polymer skin adjacent the core. The filaments which made up the braid in the sheath encircle the core in a helical pattern extending along the stem and tapered section provided resistance to torsional stresses on the stem. Also disclosed are novel methods for making the prosthesis construction.

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Phoenix, AZ, United States of America

Ron Yapp