DE8409993U1 - Prosthesis socket - Google Patents

Description

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ME34.2 page 4

B e s e h re i b u η q

The invention relates to a prosthesis socket of the type specified in the preamble of claim 1.

In the case of cementless prostheses, it is occasionally necessary to use additional bone screws that are screwed into the femur in the transverse direction secure against loosening. In the known prosthesis shafts, which only have cylindrically shaped openings, there is the disadvantage that the used Screws have to find a hold in the bone itself and thus, in addition to being difficult to handle, the risk of loss

Standing by metallosis is given.

The invention specified in claim 1 is based on the object of providing a prosthesis socket of the type mentioned at the beginning Specify a type that allows the screwing in of conventional bone screws and thus keeps the surrounding bone area free from such stresses.

It is particularly advantageous in the invention that the insertion of the corresponding plastic parts into the prosthesis socket without any significant weakening of its structure can take place, the penetration of screws - with appropriate design - from all axial directions is possible.

In the case of shafts with an oval cross-section, the penetration of plastic elements takes place in order to penetrate the long one

ME34.2 page 5

The area surrounding the oval side by introducing plastic parts that form the cross-section of the prosthesis socket penetrate prismatically in the transverse direction.

In the other case - when containing one or more screws parallel to the long side of the cross-sectional oval Surface are to be screwed in, in the area of these surfaces by means of dovetail guides, which in Direction of screwing are directed, plastic elements are preferred elements in corresponding recesses close to the surface joined, which contain a bulge on the rest of the prosthesis surface, so that on the one hand a sufficient material cross-section to screw in the screw for Is available, on the other hand, the outer contour of the prosthesis but is changed as little as possible.

This means that there is no possibility of screw connections in the shaft area remote from the joint, in particular due to the attachment associated significant weakening of the shaft cross-section.

The plastic elements in question can be without Difficulties insert into a preformed metal shaft with corresponding recesses and can be exchanged if necessary.

Advantageous further developments of the invention are characterized in the subclaims or are described in more detail in the illustration below together with a preferred embodiment of the invention. Show it:

1 shows an exemplary embodiment of the invention Prosthesis shaft viewed in the frontal (LM) plane

ME34.2 page 6

and

Fig. 2 the same embodiment in the sagital (AP-) Seen on the plane, i.e. viewed in the medial direction. 5

At its end near the joint, the prosthesis socket 1 has a conical connection 2 for receiving a ball, which exchangeable and not shown in the drawing. The shaft surface has a substantial curvature in the area near the neck, which runs in the plane of the drawing of FIG. The shaft is in areas 3, 4 and 5 smooth in constriction areas, while the other parts of the shaft are repositioned, i.e. have a grainy surface structure, as indicated locally symbolically by the intersecting lines is.

In the area of maximum curvature near the neck, where is the shaft cross-section more important? is oval, the shaft is prismatic in the transverse direction Continuous oval recess (vertical plane of drawing according to FIG. 1) a plastic part filling the recess 6 made of polyethylene, which is held by a tight fit in this recess. This plastic part enables it is to screw bone screws into the prosthesis shaft perpendicular to the plane of the drawing, which the prosthesis in the Lock the implanted state in the originally intended position.

The location of the screw connection can be seen in the X-ray image and can be reached precisely.

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In the illustration in FIG. 2, two further plastic parts 7 and 7a can be seen which are inserted into dovetail guides 8 and 9, which are indicated by dashed lines in the illustration according to FIG.
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They can be inserted into these recesses perpendicular to the plane of the drawing and have hump-like outer elevations which protrude beyond the shaft line of the prosthesis. This results in a sufficient material strength for screwing in the bone screw without significantly weakening the prosthesis material. As the plastic material is formed continuously in the screwing direction, i.e. that the plastic part is in a continuous - and was not inserted into a sack-shaped recess, the bone screw can be turned into it as far as you want, without hitting a stop.

The design of the dovetail guides also ensures that the remaining shaft cross-section is sufficient to ensure the load-bearing capacity. Even so, the attachment points are straightforward can be found and form holding points, which cause a good fixation of the prosthesis shaft in the bone area. The preferred plastic material is polyethylene Use.

The implementation of the invention is not restricted to the example given above. Rather are one A large number of variants are conceivable, which of the solution shown also with fundamentally different designs Make use.

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Claims (9)

ti »τ · ιψ r» ·· ·· · MECRON March 27, 1984 medical products GmbH D-1000 Berlin ME34.2 prosthesis socket claims 1. Metal prosthesis socket for cementless implantation with at least one recess for receiving a fastening screw, characterized, ME34.2 page 2 that a part (6, 7, 7a) made of plastic is inserted, which extends in at least one direction perpendicular to the outer surface of the prosthesis socket (1) extends into at least half of its cross-section as a solid body. 2. Prosthesis socket according to claim 1, characterized in that that that outer surface of the plastic part (6) which is parallel to the plane in which the Prosthesis curvature runs in the area near the joint, is directed, extends in continuation of the shaft surface. 3. Prosthesis shaft according to claim 1, characterized in that at least one in the shaft Plastic part (7, 7a) is provided, the more massive Area extends mainly in one direction 2 <J which is parallel to the plane of the main curvature of the prosthesis runs. 4. Prosthesis socket according to claim 3, characterized in that the plastic part (7, 7a), which is inserted into the metal structure by means of dovetail guides, has a thickness transversely to the insertion direction which at least slightly exceeds the cross section of a bone screw.
30th ME34.2 page 3 5. Prosthesis socket according to one of the preceding claims / characterized in that the plastic part (6/7, 7a) prismatic the shaft is formed traversing. 6. Prosthesis socket according to one of claims 1 to 4, characterized »that the plastic part (7» 7a) by means of a in the direction of the mas sive extension running dovetail guide in the prosthesis shaft (8/9) is inserted. 7. Prosthesis socket according to one of the preceding claims * - marriage, characterized in that the surface of the plastic part (6, 7, 7a) inserted into the shaft, nestling against the side of the Surface of the shaft (2) merges into this without a step. 8. Prosthesis socket according to one of the preceding claims, characterized in that, the plastic used is polyethylene. 9. Prosthesis socket according to one of the preceding claims, characterized in that i the plastic part (6, 7, 7a) in the screwing direction | Prosthesis shaft (2) completely traversed. : _ / 4