Cement jacket for a cemented artificial joint stem and artificial joint having the cement jacket

Abstract

The present invention relates to a cement jacket for a cemented artificial joint stem, wherein shear force detrimental to the service life of an artificial joint can be markedly reduced while the compressive force beneficial for the strengthening of the bone is significantly increased and stress shielding phenomena which makes the bone resorbed can also be markedly relieved, due to the construction of the cement jacket which can be fixed within the bone canal and can enclose the surface of the stem so as to allow for the artificial joint stem to slide vertically relative to the bone, and wherein the osteolysis of a femur due to the infiltration of wear particle can be minimized by curbing the gap formation between the femur and the stem. According to the invention, there is provided a cement jacket 10 for an artificial joint stem 21 for enclosing at least a part of the cemented artificial joint which is inserted longitudinally in the opening formed in the bone canal of a human body. The cement jacket 10 may be made of all cement, or the inner surface of said jacket of cement is coated with a plastic film 12 having a high resistance to abrasion. The cement jacket itself could be reinforced by imbedded wire or fiber. And preferably the outer surface of said cement jacket 10 is formed with discharging paths 13 in the longitudinal direction, so that excessive cement paste poured into the bone canal previously for the surgical purpose can be easily discharged upward at the time of inserting the jacket.