Universal extractor for total endoprostheses (TEP) of the knee joint

Universal extractor for a knee prosthesis, comprising

• a T-shaped element having a vertical member and a horizontal member affixed to a first end of the vertical member, the horizontal member comprising an extraction plate for receiving an extraction force upon extraction of the prosthesis and the vertical member comprising a securing arm, a second end portion of the vertical member defining a terminal end portion of the vertical member from which a pair of fork-shaped prongs and a prong bridging member extend so as to define a slot between the prongs, the prongs being symmetrical about an axis that passes therebetween and that is parallel with a longitudinal axis of each of the prongs and extending along their longitudinal dimension into a plane that is orthogonal to a plane in which the extraction plate extends in a longitudinal direction of the extraction plate;
• a scissor mechanism comprising two intersecting arms, an intersecting portion of the arms being received in the slot so that each of the arms is free from direct contact with either of the prongs at a point directly adjacent the bridging member and the prongs, a first pin pivotably connecting the arms to the second end portion of the vertical member and to the prongs, and a respective clamping jaw carried on a distal end of each of the arms, the clamping jaws each being shovel-shaped or substantially U- or V-shaped or of a shape intermediate a U and a V, the point of connection of the arms to the second end portion defining a locus of force transfer between the arms, prongs and extraction plate upon extraction of a prosthesis so as to optimize an extraction force exerted upon the extraction plate during extraction of the prosthesis;
• and
• an adjustment mechanism comprising an elongated member including an attached actuating portion, the adjustment mechanism adjustably connecting proximal ends of the arms so as to adjustably fix a distance between the proximal ends thereby to effect fixation and release of the jaws to and from a knee prosthesis, the arms being movable during a scissoring movement thereof through a plane that is orthogonal to the plane in which the longitudinal dimension of each of the prongs of the fork-shaped second end portion of the vertical member extends, and the actuating portion laying in a plane that is parallel to the plane through which scissoring movement of the arms occurs and orthogonal to the plane through which the longitudinal dimension of each of the prongs extends.