초록 ▼

The invention shows knock-out instruments for the shanks of hipjoint prostheses, the said instrument consisting of a shank (1) with a coupling-part for a sliding hammer (not shown) as well as of an extension-piece (3) which may be applied in the knock-out direction. The extension-piece (3) is connec

The invention shows knock-out instruments for the shanks of hipjoint prostheses, the said instrument consisting of a shank (1) with a coupling-part for a sliding hammer (not shown) as well as of an extension-piece (3) which may be applied in the knock-out direction. The extension-piece (3) is connected rigidly to the shank and stands away from it like a foot at an angle a8) which may be slid from one side over the neck of a hipjoint prosthesis and encircles it over an angle of up to 180°, the width inside the recess measured across the 180°being greater by a clearance than the smallest diameter of the neck of the prosthesis, measured in the same direction. The recess is further formed so that it engages the prosthesis in the area of the neck at three points arranged to lie in a plane substantially parallel to the axis of the shank so that, when the line of action of the sliding hammer is offset relative to the shank axis, a moment generated thereby is opposed by a moment generated between the extension piece and the neck at these three points.

대표청구항 ▼

A knock-out instrument for a hipjoint prosthesis, comprising a shank (1) with a coupling-part (2) for a sliding hammer, an extension-piece (3) connected rigidly to the shank (1) and extending away from the shank at an angle a20°and 60°, the extension-piece including a recess (8) formed to be slid fr

A knock-out instrument for a hipjoint prosthesis, comprising a shank (1) with a coupling-part (2) for a sliding hammer, an extension-piece (3) connected rigidly to the shank (1) and extending away from the shank at an angle a20°and 60°, the extension-piece including a recess (8) formed to be slid from one side over the neck (6) for engaging the neck over an angle of up to 180°, a width measured inside the recess being greater than a smallest diameter of the neck (6) measured in the same direction to provide clearance between them, the extension-piece being shaped to touch the neck (6) at two points (11) offset by 180°and at a lowest point (7), all points (11, 7) lying substantially in one plane which is parallel with the axis (9) of the stem so that a moment generated by the hammer when its line of action is offset with respect to the stem axis is compensated for by a moment generated at said points, whereby the generation of laterally acting forces between the shank and surrounding bone tissue is prevented.