Abstract: Modular set of an outer shell (1) for an artificial hip joint pan, comprising a shell-shaped outer part (2) and an anchoring aid (7) which is designed as a lug (3, 4), a spike (5) or a hook (6), with the shell-shaped outer part (2) having an end surface (2a) at its equator with bores (2b), and with each anchoring aid (7) having a securing part (3a, 4a, 5a) which is designed to be matched with respect to the end surface (2a) in such a manner that the securing part (3a, 4a, 5a) can be secured at the shell-shaped outer part (2) by means of a screw (6) which engages in the bore (2b).

Abstract: The invention shows a filling apparatus for the introduction of bone cement into the intramedullary cavity of a bone, preferably into the cavity of a femur bone. The apparatus has a filling cannula, at the end of which a rubber sleeve in the form of a sheet metal bell is fastened which projects with its movable part radially beyond the diameter of the filling cannula and axially beyond a lowermost outlet aperture of the filling cannula. Because the sleeve is executed in the lower expandable part with a thickness 1 mm<s<2 mm and is fastened above an uppermost outlet aperture of the filling cannula at a distance 3 mm<1<50 mm and projects with its lower edge beyond a lowermost deflection edge 11a of a lower outlet aperture by a distance 5 mm<a<50 mm, its cross-section adapts to the cavity wall when being introduced without getting caught up and seals it during the expulsion of the bone cement.

Abstract: A body (2) for distributing bone cement (8) rests by an elastic collar (4) against the outer edge of a hollow (1) in the bone and has a passage (5) through into the hollow (1) in the bone, into which a syringe (6) for bone cement may be inserted. In the hollow (1) in the bone the body (2) is made as a displacement body of the shape (3) of the implant which is to be inserted later. During injection into the space between the body and the hollow in the bone a designed pressure is maintained until the viscosity of the bone cement (8) is adequate for taking the body (2) out of the hollow (1) in the bone without bone cement (8) flowing back. Subsequently the actual implant may be pressed into the thus prepared but still plastically deformable countermould of bone cement (8) .

Abstract: The invention shows a double-cup hipjoint socket of oval cross-section with a spherical bearing cup (4). the metallic outer cup (1) exhibits a constant thickness of wall and is provided with openings (3) for anchoring in the pelvic bone. The inner cup (2) of plastics may be latched to the outer cup (1) and by springy tongues (11) on the opposite side. The oval shape is generated by inserting straight intermediate pieces (5,6) in the inner and outer cups. Through the elongated shape of the outer cup (1) which may be inserted in different directions, an optimum fastening may be striven for. The definitive position of the spherical bearing cup (4) is established for the first time by the insertion of a fitting inner cup (2). In doing so the spherical bearing cups (4) may be shifted in the equatorial plane of the outer cup (1) and/or in the direction of the polar axis of the outer cup.

Abstract: 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 .alpha. of between 20.degree. and 60.degree.. The extension-piece exhibits a recess (8) which may be slid from one side over the neck of a hipjoint prosthesis and encircles it over an angle of up to 180.degree., the width inside the recess measured across the 180.degree. being greater by a clearance than the smallest diameter of the neck of the prosthesis, measured in the same direction.

Abstract: A plastic acetabulum is provided with a plurality of cavities in the outer surface. Each cavity opens conically to the exterior of the acetabulum and the cavities are disposed in concentric rows about the axis of the acetabulum. The cavities are provided with a roughly fixed ratio of depth (t) to width (w) with the volume (v), depth (t) and width (w) decreasing from an edge of the acetabulum to a peak of the acetabulum. The depth and width of the cavities each decrease exponentially in proportion to the ratio of the diametric spacings of the cavity rows. Likewise, the volume of the cavities decrease exponentially from row-to-row in the direction of the peak of the acetabulum.

Abstract: A femoral head prosthesis is provided with a slot which extends from ventral to dorsal within the distal zone of the stem to separate a tongue-like core from a resilient peripheral portion. The tongue-like core is able to move in the slot in response to bending and twisting stresses. The shear forces which these stresses produce in a transition zone between the bone and the stem are thus, at least, reduced. The slot may be of U-shape with arms parallel to the sides of the stem or with arms parallel to the axis of the stem. One arm of the slot may also be shorter than the other and one arm may be of widening shape relative to the other.

Abstract: The reinforcement for the proximal region of a bone cement bed for a femoral head prosthesis includes a grid of crossing members at least some of which are wavy. The wavy members have a high wavy shape lengthwise and spring in as the gap between a bone cavity and a prosthesis stem narrows. The prosthesis is fixed by averaging out of the restoring forces and the gap size mechanically until the bone cement has cured.

Abstract: The distal region of the fixing stem of the femur head prosthesis is formed with an elongated slot to increase resilience. The slot is closed at the distal end by a closure element which facilitates implanting of the stem without destroying the increased resilience.

Abstract: The wire mesh reinforcement is provided with a wire mesh lattice having wire-like structures for embedding in a bone cement bed as well as a plurality of spike-like fixing elements which project from the lattice for securement in a bone. The fixing elements serves to anchor the lattice in place before introduction of a bone cement.

Abstract: The fixing stem is provided with a plurality of projections in the proximal region of the blade. Each projection is in the form of a pyramidal prism directed in a distal direction. The apex of each projection is sharp and is inclined at an acute angle to the surface of the blade. In addition, the projections are staggered along the length of the proximal region of the blade and are of decreasing height in the distal direction.

Abstract: The femoral head prosthesis has a straight fixing stem for implantation in a femur which is provided with a longitudinal bore which extends along the axis of the stem. The stem can be slid along a centering rod previously positioned within a surgically prepared bone cavity of the femur to guide the stem into a bone cement bed. The centering rod is initially put in place with a cavity barrier followed by placement of the bone cement bed. After initial curing of the bone cement, the rod can be disengaged from the cavity barrier and removed from the stem.