DE3205526C2 - - Google Patents

Description

The invention relates to a socket support implant for im Plantation using bone cement, according to the Oberbe handle of claim 1.

The problem of reinforcing the pan bottom to over bridging of bony defects for a safe recording an artificial pan in the bones of the Beckens always arises when the anatomical Conditions due to acetabular dysplasia, defect formation on Pan edge or defect (including injuries) in the pan pan dens does not securely anchor the artificial pan ensure more. But even with anato initially cheap mixing ratios is the mechanics of cemented Pan due to the loss of the natural hip joint in if changed as it is exclusively at the Hauptbe load area on the pantile roof comes to voltage peaks, which is not in the sense of a simple cementing Transfer the power distribution to the rest of the pan base becomes. It is similar to the seat of the prosthetic stem for bone resorption at the cement-bone boundary, for Loosening and the typical steep tipping of the pan.

There are already pans to reinforce the bottom of the pan support shells have been developed. The previous developments The pan support shells are only on it rectifies a defect in the case of existing defects bridging with support only at the edge of the pan cause.  

Such a pan support is known from DE-AS 23 14 708 known shell implant, in which a spherical hollow body in the form of a spherical cap and an annular Support flange is provided with numerous openings. This implant is made of a relatively rigid material manufactured and used for lateral support on still ge healthy structures.

Furthermore, it is for better anchoring of rigid spherical pan support shells known, these with diver Giving fasteners to be provided on the External surface are attached or together with the pans support shell consist of one piece and differ from this extend away for a sufficient distance so that a intramedullary attachment is achieved (DE-OS 16 161 51). The divergent fasteners can by several divergent mandrels are formed. These bowls but differ in the forces that occur not from the rigid pan support shells mentioned above where there is tension in the area of the pantile roof comes to a point. The thorns can already because of their shape the introduction of forces acting in the direction of the mandrel remaining bone structure only in a limited form take over.

While the problem of the si Securing a pan support shell in the foreground is another pro in this context blem important: due to the rigidity of the known Implants, there is a crucial disadvantage punctual loads at the point of maximum force  shot at the pan bay. To the adverse effects To avoid such point loads, it is became known, instead of rigid pan support shells Openworked shells made of perforated sheet metal (e.g. from Titan) in various forms (The Journal of Bone and Joint Surgery, Vol. 62-A, No. October 7, 1980, Pages 1059 to 1065).

These baskets have the other implants mentioned above compared to the main advantage that they are the result their bendability and deformability compressive forces can take and distribute, so that the degradation of the Place of the maximum pressure load impinging force pointed occurs. Accordingly, the latter baskets the relatively best solution for the known implants However, one remains with such baskets essential part of the pan mechanics not taken into account, so that they appear to be in need of improvement.

The invention is based on the object to provide further resources for additional anchoring of the socket support implant tats in the adjacent bone areas using bone to enable cement.

This object is achieved with the in the characterizing part of claim 1 specified measures solved.

The invention is based on the knowledge that Befe strengthening and force transmission into the bony residual structure must be optimized at the same time in order to achieve a maximum To achieve the load-bearing capacity of the overall construction.

The forces on the natural acetabulum (at Load) are calculated according to the arch pillar construction  tion of a bridge on the three pillars of the bony Socket, the colon, the sit and the pubic bone, transfer. This crucial feature is missing from the artificial pan and in the usual pans support shell constructions. However, it can ver become real that by extensions on the basket, which too hanging together with the basket in the pillar of the bony Protrude into the pan bearing and a cement con with cement structure, the entire pillar system in the Ze ment composite construction is included. Already at The presence of two such protruding into the pillars Tilting of the pan is not an extension (e.g. spigot) more possible because in this case on one side in the area of the pin protruding into the corresponding pillar compensating tensile forces occur.

Advantageous developments of the invention are in the Subclaims specified.

With the construction of the implant according to the invention in Shape of a relatively compliant basket with relative rigid appendages, each toward the from the hip joint area of the strut or ischium or pubic bone, it has succeeded inadmissible Avoid force peaks while remaining one to achieve secure attachment of the implant.

Usually a simple basket will do. At Large media defects require tabs on the basket Lich anchoring to the ilium and ischium possible and the defect according to a "prestressed concrete  Construction "help to bridge. The template according to the invention also helps difficult ones Situations of the reconstruction of injured pan bottoms to meet. You can use the template and the one fold basket for both the left and right side be used, while for the basket with tabs one right and left form must be available.

Preferred exemplary embodiments are shown in the drawing le described.

Figs. 1 and 3 each show a side view un terschiedlicher embodiments of a basket. The

Figs. 2 and 4 show the to FIGS. 1 and 3 ge impaired plan views as viewed in the concave side of the basket.

The basket K shown in Figs. 1 to 4 is adapted in its outer concave shape to the concave shape of an artificial cavity that will create ge in the hip area of a pelvis in order to be able to introduce an artificial pan. The basket K is intended to serve as a force distributor between an artificial socket to be cemented in its interior and the artificially created cavity in the bony pelvis. The edge of the basket has a recess O for the obturator foramen. In addition, the edge of the basket K is reinforced by a reinforcement V. The basket K , for example made of titanium sheet, is perforated in a known manner. It has two novel extensions Fd and Fs , of which the one labeled Fd runs in the same direction in which, in a natural pelvis, the iliac bone strives away from the area of the hip joint. Correspondingly, the extension Fs has the direction of a ischium striving away from the hip joint region.

For these extensions - starting from the artificial Cavity - receiving holes in the ilium or ischium in Direction introduced from their respective longitudinal directions will.

During an operation which is carried out with the aim of inserting an artificial hip socket, the cavity K is first inserted into the socket with an appropriate template after the cavity has been created. Then a receiving hole is drilled into the ilium and the ischium with the help of the hollow cylinders Hd and Hs . Finally, a basket according to FIGS. 1 to 4 is inserted into the artificial cavity in such a way that the extensions Fd and Fs protrude into the receiving holes previously drilled. In this position, the basket is inserted into the artificial cavity. It can also be attached to the ilium or ischium using tabs Ld, Ls ( Fig. 3 and 4). These tabs are located on the edge of the basket K and have holes L for fastening screws B.

The basket K is preferably a one-piece structure and the tabs and at least one extension (Fd in FIGS . 3 and 4) are connected in one piece to the basket K. The extensions are preferably also perforated and bottle-shaped neck. As a result, they are more rigid than the rest of the basket and thus take into account the fact that, even in the natural pelvis, the transition area between the hip joint area and the ilium or ischium is more rigid than the other parts of the hip joint. Due to the relatively rigid extensions on the basket K , the forces transmitted from the artificial pan to it are preferably introduced into the abovementioned pillars, ie into the ilium and the ischium.

When inserting the basket according to FIGS. 1 to 4 with its diverging extensions Fd and Fs , a problem arises: If the receiving holes for the extensions have only a slightly larger diameter than the extensions themselves, the insertion of extensions rigidly attached to a basket is in the receiving holes are not readily possible because the structure consisting of the basket K and the sets cannot be moved simultaneously in the direction of the axis of the extension Fd and the axis of the extension Fs . Therefore, at least one of the extensions can be retrofitted, ie at a time when the basket with the other extension Fd ( FIG. 3) has already been inserted into the corresponding opening. In Fig. 3 it is shown how the extension Fs can be subsequently screwed from the interior of the basket K into a nozzle S.

Claims (3)

1. Cup support implant for implantation by means of bone cement, which is designed as a basket with openings and, due to its flexibility and deformability, can absorb and distribute pressure forces, characterized in that
that extensions (Fd, Fs) are provided on the outside of the basket (K) , which point in the direction of one of the longitudinal directions of the ischium and / or the ilium and / or pubis striving away from the hip joint area,
that the extensions (Fd, Fs) are designed as hollow cylinders, the walls of which are provided with openings,
that one of the extensions (Fd) is integrally connected to the basket (K) and
that each further extension (Fs) can be rigidly connected to the basket (K) after insertion. 2. Implant according to claim 1, characterized in that the basket has at least one tab at the edge (Ld, Ls) with at least one hole (L) for egg ne fastening screw (B) . 3. Implant according to one of the preceding claims, characterized in that the edge of the basket has a reinforcement (V) .