Abstract: System of intervertebral prostheses which comprise a prosthesis core (5) and two cover plates (4, 6) which enclose the prosthesis core (5) by way of internal engaging surfaces (7). The system includes corrective cover plates (6) whose vertebral contact surface (12) is lengthened in the AP direction dorsally beyond the extent of standard prostheses (4). In sagittal section, the corrective cover plates are dorsally thickened, in particular wedge-shaped. The inner face (11) of the part (10) constituting the dorsal lengthening is beveled or recessed.

Abstract: A knee prosthesis includes a femoral component with condylar sliding surfaces which are rigidly interconnected, a tibial component provided with a tibial platform which is linked to it in a non-rotatable manner and has tibial sliding surfaces which cooperate with the condylar sliding surfaces, and a coupling device which forms a flexion bearing with the femoral component and a rotational bearing with the tibial component, the axis of said rotational bearing being inclined relative to the tibial direction. In order to achieve a more advantageous force distribution in the prosthesis and a restoring force upon rotation of the prosthesis parts, the prosthesis is configured such that the normal with respect to the area of the tibial sliding surfaces which cooperates with the condylar sliding surfaces and transmits most of the load in the extension position is less inclined relative to the tibial direction than is the axis of the rotational bearing, as seen in a side view or sagittal section.

Abstract: A tool and method for making vertebral incisions which form the lateral surfaces of a ventral opening in a vertebra for receiving a prosthesis that partially replaces the vertebra includes use of a saw jig with fittings configured for attachment to at least one of two vertebrae positioned superiorly and inferiorly adjacent to the vertebra and with guide fittings to provide a cutter guide for the incisions.

Abstract: A cervical intervertebral prosthesis includes two cover plates which are each configured to be connected to adjacent vertebral bodies. At least one of the two cover plates has a toothed portion which faces toward the vertebral body and whose teeth have a steep, ventrally directed flank and a less steep, dorsally directed flank. When the prosthesis is fitted with sufficient pressing between its adjacent vertebral bodies, the combination of the serrated toothed portion and the abutment surface is sufficient to hold the prosthesis securely in the desired position. In many cases this makes it possible to dispense with additional screw fixation. The flange carrying the abutment surface is in this case expediently shortened so that it can be accommodated in a recess of the bone so that the prosthesis does not protrude ventrally beyond the ventral alignment surface of the adjacent vertebral bodies.

Abstract: The invention relates to an endoprosthesis for replacement of a joint, 2 slide surfaces having different contours and correspondingly determining movement planes for in each case 1 bearing being formed by an intermediate part 2. Provision is made according to the invention for a clamping bracket to enclose the slide surfaces of the intermediate part and to be arranged thereon such that it is arranged free from the movement planes defined by the slide surfaces having different contours. It is thus also possible to strengthen endopreostheses which have complex biomechanics having a plurality of degrees of freedom.

Abstract: A knee prosthesis includes a femoral prosthetic part which forms a pair of condylar gliding surfaces, a tibial part that has tibial gliding surfaces cooperating with the condylar gliding surfaces and a coupling part that connects the femoral and tibial parts so that they can rotate about a rotational axis that is approximately parallel to the axis of the tibia. If the femoral and tibial parts have the same anteroposterior alignment, an applied load is borne by a central region of the tibial gliding surfaces. The tibial gliding surface slopes upwardly relative to the prosthesis both in front of and behind the central region of the tibial gliding surface so that when the femoral and tibial parts rotate against one another, each of the condylar gliding surfaces remains in contact with its corresponding tibial gliding surface.

Abstract: A surgical implant or instrument has two parts, one sliding on the other, the lower part being provided with a threaded bore and the upper part being provided with a passage orifice for receiving a fixing screw. The set screw can be received over its entire length beneath the upper part in the threaded bore and includes, at its upper end, a dog point which is thinner than its threaded part and which is provided with a slit, groove or hexagon socket for a screwdriver, the diameter of the passage orifice being smaller than that of the threaded part and larger than that of the dog point. An elastic device is provided for the implant or instrument which pushes the fixing screw into the fixing position.

Abstract: The invention relates to a process for producing a medical implant from a titanium alloy, by investment-casting the titanium alloy in a casting mold which corresponds to the implant that is to be produced. The invention provides for using a ?-titanium alloy, hot isostatic pressing, solution annealing, and then quenching. The invention also covers a corresponding medical implant which has been produced from a titanium alloy using the investment casting process. The titanium alloy is a ?-titanium alloy and has a mean grain size of at least 0.3 mm. The invention allows economical production of objects from ?-titanium alloys using the investment casting process. The invention thereby makes it possible to combine the advantageous properties of ?-titanium alloys, in particular their excellent mechanical properties, with the advantages of producing objects by the precision casting process.

Abstract: Surgical instrument for inserting an intervertebral prosthesis, having first and second prosthesis holders (52A, 52B) for a pair of prosthesis plates, which holders are connected to one another by a parallel guide (57) and can be spread by a lever arrangement (131). The first of the prosthesis holders is arranged on an elongate instrument body in order to give the surgeon an exact picture of the orientation of the prosthesis and to allow force to be exerted in exactly this direction. The actuating lever (131) is articulated with its front end on the second prosthesis holder (52B) so as to pivot about a spindle (130) extending transversely with respect to the longitudinal direction of the instrument body (51) and to the direction of spreading. Behind this spindle (130), it has a limit stop (133) which acts directly or indirectly on the instrument body (51) or the first prosthesis holder (52A). The lever arrangement can also be the other way around.

Abstract: An intervertebral prosthesis, in particular for the cervical spine, has two attachment plates connected in an articulated manner. The attachment surfaces of the attachment plates, which are configured for attachment to adjacent vertebral bodies have a base surface configured to bear on the surface of the vertebral bodies, and self-tapping fixing projections rising from the base surface. These fixing projections are formed by at least one pair of ribs which extend in opposite directions obliquely with respect to a predetermined implantation direction and whose side faces oriented more away from the implantation direction are steeper than their side faces oriented more in the implantation direction. The ribs can be toothed.

Abstract: A hip prosthesis includes a shaft which can be inserted into a hole in the femur without using cement. The proximal section of the shaft includes a base body having a form that is complementary to the shape of the hole in the femur into which the shaft is to be inserted. The hole is made using a tool of a shape corresponding to the base body. The base body has a cuneus rib raised on its dorsal or ventral surface that has a width in its center that is at least three times its height. The rear surface of the cuneus rib has rough and abrasive properties.

Abstract: A medical implant has a secured bone screw which is guided through a bore of the implant. The bore has a thread matching the thread of the bone screw. Between the head of the bone screw and the thread thereon, there is an unthreaded portion whose diameter is not greater than the free inside diameter of the threaded bore. These threads prevent axial passage of the bone screw through the bore without turning. Turning is inhibited or excluded by an arrangement preventing turning.

Abstract: An arrangement includes a holder for holding intervertebral prostheses, at least two intervertebral prostheses of different widths which each have two end plates with ventral flanges and a joint core arranged between the end plates. The holder includes a support plate with at least one opening formed therein that is configured to receive one of the intervertebral prostheses and has a width which is greater that the maximum width of the intervertebral prostheses. A pair of steps is formed on at least one longitudinal edge of the opening that has flanks that are directed toward one another and spaced apart such that the flange of the intervertebral prosthesis inserted into the opening is centered in the opening. The pair of steps can be configured as projections or depressions.

Abstract: The invention relates to a joint prosthesis having a shaft made from a titanium alloy; according to the invention, it is provided that at least the shaft (10) is investment-cast and has a body-centered cubic crystal structure. A titanium alloy having this crystal structure (known as ?-titanium alloy) has an advantageously low modulus of elasticity which is well matched to the physiological demands. Furthermore, implementation as a shaped casting allows a complex shape to be achieved. It is particularly expediently embodied as a femoral prosthesis (1) for an artificial hip joint, which has an elongate shaft (10) with grooves (14) and sawtooth-like projections (15) for bone anchoring.

Abstract: A bone spreader includes two tubular pin holders which are connected to one another by a parallel guide system, and two pins that are configured to be connected to the bone parts that are to be spread apart. In order to give the bone parts that are to be spread apart a more secure position in relation to one another, at least one of the pin holders is provided with a locking device for a pin located in the pin holder. This locking device includes a locking finger which is movable tangentially with respect to the pin holder and which, in the locking position, engages in a transverse groove of the associated pin and can be formed by a pivotably mounted hook.

Abstract: In an intervertebral joint prosthesis for an intervertebral space of the cervical spine, the intervertebral space is delimited by the end plates of the adjacent vertebral bodies. The bearing surfaces of these end plates, when viewed in a frontal plane, have edge zones laterally adjacent to a substantially flat central area that are more strongly curved than the flat central area. These edge zones are also more strongly mineralized than the central area and are therefore particularly stable. At least one of the prosthesis surfaces intended to bear on a vertebral body surface has a lateral extend reaching into the edge zones. The convex curvature of this prosthesis surface, when viewed in the frontal plane, is at least as great as the corresponding curvature of the surface of the end plates. This ensures that the prosthesis is also supported on the particularly stable edge zones, and these edge zones do not have to be subjected to any substantial removal of material.

Abstract: An intervertebral prosthesis system, in particular for the cervical spine, includes at least two types of prothesis. The type of prothesis includes a first cover plate that is configured to be connected to a first vertebral body, a second cover plate that is configured to be connected to a second vertebral body, and a prothesis core which is held by a seat on the first cover plate and forms an articulation with the second cover plate. The core of the first type of prosthesis is movable in the anterior-posterior direction relative to the first cover plate. Mobility can also be provided in the lateral direction and rotational direction. The second type of prosthesis of the system may be the same as the first type of prosthesis or may be different, but in all examples of the second type of prosthesis the core is not movable relative to either cover plate.

Abstract: Cervical intervertebral prosthesis with two connection plates (1, 5) for connection to in each case one of the adjacent vertebral bodies, and with a hinge core (20). The latter forms, together with one connection plate (1), a hinge with a concave hinge surface (11) on the hinge core (20) and with a complementary convex hinge surface on the connection plate (1). It bears on the other connection plate (5) via a slide surface (17) which extends substantially parallel to the direction of the connection plate (5) and which permits a relative movement in this direction and is surrounded by an edge (15) limiting this relative movement. The concave hinge surface (11) encloses the convex hinge surface within a solid angle (28) of at least 90°. Its part lying within this solid angle lies inside the recess (16) surrounded by the edge (15). The stability of the prosthesis with respect to laterally incident forces is thereby increased.

Abstract: A pair of intervertebral prostheses is configured to be implanted above and below a given vertebral body and each has an end plate configured for connection to this vertebral body and a securing flange which is assigned to the end plate and is configured for connection to the vertebral body from the ventral direction in an implanted position. To ensure that the securing flanges also have enough space in front of vertebral bodies of low height, they are offset relative to one another in such a way that one securing flange is arranged centrally, and the other securing flange is arranged eccentrically in a symmetrical configuration. The offset can be provided in the lateral direction and/or in the anterior-posterior direction relative to the implanted position.

Abstract: An instrument for inserting a pair of sliding prostheses includes a supporting plate, two clamps adjustable through a spacing range, and two vertically adjustable sliding-surface bearing supports configured to support the sliding prostheses in the area of the sliding surfaces on the supports. Each of the clamps is configured to receive one of the pair of sliding prostheses and has clamping jaws configured to interact with the side edges of the corresponding sliding prostheses. The supporting plate has a slide guide formed thereon and an adjustment spindle for at least one of the two clamps. The sliding-surface bearing supports are configured in fixed positions on the supporting plate and having a width which corresponds to the adjustable spacing range of the clamps and is large enough to support the sliding prostheses in any chosen spacing.