KR20060080183A - Ankle-joint endoprosthesis - Google Patents

Abstract

An endoprosthesis used to replace an ankle joint, comprising a lower component (4) which is joined to the ankle bone (2), an upper component (3) which is joined to the shinbone (1) and an intermediate part (5) which forms a slip joint with the lower and upper components. An intermediate part (5), whose sagittal section is wedge-shaped, is provided in order to compensate for anatomical or operative irregulararities. The frontal or sagittal section of the upper component (3) can also be wedge shaped.

Description

Ankle prosthesis {ANKLE-JOINT ENDOPROSTHESIS}

Internal prostheses used to replace the ankle joint, consisting of components connected to the talus, components connected to the tibia, and the middle, are known [DE-U-88 12 806, in Hamburg, Doun Co., Ltd. of Waldemar Link Gmbh & Co. LINK STAR Totale Spunggelenkprothese, a pamphlet written by H. Kofoed. The tibial component and the intermediate portion form an interactive sliding surface allowing rotation about the longitudinal axis, the sliding surface being capable of compensating movement in the AP direction and the LM direction. Can be stabilized by natural ligament devices.

In the known prosthesis, the upper and lower sliding surfaces of the middle part are arranged parallel to each other in the front side, since the joints are replaced by the prosthesis so that no change of orientation is caused. However, the collateral and medial ligaments of the joints have often been shown to exhibit different tensions after surgery, thereby causing pain. This may be based on anatomical irregularities, or on the surgeon's choice of an undesirable resection to connect the prosthesis to the tibia.

It is an object of the present invention to prevent or mitigate imbalances on the one hand between anatomical or surgical situations and on the other hand the imbalances of the prosthesis.

The solution according to the invention is shown in the characterizing part of claims 1 or 5. According to the invention the intermediate and / or tibial component is formed in the form of a wedge. If the surgeon sees that the ligament tensions are different when using a normal prosthesis, the surgeon can compensate for this by using a wedge-shaped orthodontic component. The thicker side of the wedge shaped calibration plate is placed on the side where ligament tension may be insufficient when using ordinary components. If the surgeon realizes that the tibial resection does not proceed perpendicular to the tibial direction, or if for some other reason the faces of the prosthesis do not advance perpendicular to the tibia axis, the surgeon It is possible to insert a calibration component in which the wedge shape is located. If it is important for the lower sliding surface of the upper component to have a particular direction relative to the tibia or load direction, the surgeon will generally use the tibial component, which is formed as a corrective component. However, if the direction of the tibial resection is correct and the anatomy of the foot is considered important, the surgeon will prefer an intermediate portion that is formed as an orthodontic component.

The present invention described above does not relate to the formation of a wedge-shaped intermediate portion at the front, which is covered by patent application PCT / EP02 / 02573, which is preceded by the present invention but is not disclosed.

The fact that the upper component is in the form of a wedge is not really difficult at all, since the upper sliding surfaces as well as the lower sliding surfaces are flat or almost flat. In the sagittal plane, it is important to compare the medial section with the medial section to determine the shape of any wedge. Not only the direction of the flat upper sliding surface of the middle portion, but also the overall direction of the lower sliding surface is simply determined. If the middle part in the sagittal plane becomes thicker forward or backward compared to the normal middle part, the middle part is in the form of a wedge in the sense according to the invention.

The wedge shape in the sagittal plane can be combined with the wedge shape in the front face within the scope of the present invention. However, the wedge shape at the sagittal or front face may occur without the wedge shape at the front or sagittal plane.

The wedge angle is advantageously 1 ° to 16 °, preferably 3 ° to 8 °.

In order that the wedge-shaped orientation of the intermediate part cannot be changed by rotation of the intermediate part about the longitudinal axis, its orientation is preferably ensured by the tibia or by the tibia, and the pair of interacting sliding faces correspondingly Orientated (eg cylindrical). For this purpose, a joint between the talus and the middle is suitable.

In order for the surgeon to select various wedge angles, the surgeon must be able to use a plurality of different orthodontic components for each prosthesis. In order to reduce the consumption associated with this, the calibration component is preferably configured as simply as possible. It may therefore be desirable to assemble with standard and wedge parts that remain constant at all times. Standard parts come in a simple structure. Only wedge forms need to exist in various variations. This is particularly true where the upper component is used as the calibration component and the standard component forms the means necessary for fixation on the tibia.

The invention is now described with reference to the drawings, in which preferred embodiments are shown.

1 is a cross-sectional view of a sagittal section through a joint provided with an artificial insert.

Figure 2 is a perspective view of the artificial implant in detail.

3 is a perspective view showing the placement of the upper and lower prosthetic components to be implanted prior to insertion of the intermediate portion.

4 shows a front section of the upper calibration component.

5 shows a sagittal section of the upper calibration component.

6 is a diagram illustrating a sagittal section of a calibration intermediate portion.

Figure 7 shows a top calibration component formed in two parts.

An artificial insert consisting of the upper component 3, the lower component 4 and the intermediate part 5 is disposed between the tibia 1 and the talu 2. The upper component 3 comprises a plate shaped portion 6, the lower side 7 of which forms a flat sliding surface. The protrusion 8 functions for fixation in the corresponding ablation recess 9 of the tibia 1.

The lower component 4 forms a sliding face 10 which can be formed convexly curved, cylindrical or wedge shaped. This component comprises a rib, the rib being in the relative direction of motion of the intermediate part in the bending motion and the traction motion. The lower component also includes a side 12 of the lower component for interacting with the corresponding sliding face of the tibia 1 and fibula 13.

The intermediate part 5 has a flat upper side 15 which fits on the sliding face 7 and a lower sliding face 16 which is designed to complement the sliding face 10 of the lower component 4. This lower side has a groove 17 for receiving the rib 11. The intermediate part 5 is thus guided laterally with respect to the lower component 4. Only flexion and traction are allowed.

Preferably, the upper component 3 and the lower component 4 are made of metal and the middle part 5 is made of plastic which is advantageous for sliding, such as polyethylene. However, other materials with sufficient strength and sliding performance may also be used, for example ceramics.

By means of complementary forms of the sliding faces 10 and 16 and by the ribs 11 interacting with the grooves 17 the intermediate part 5 is not rotatable about the longitudinal axis direction with respect to the ankle component 4. Its orientation is also fixed by the orientation of the lower components. While the illustrated embodiment completely excludes this type of rotational movement about the longitudinal axis between the lower component and the intermediate part, rotational movements are permitted within predetermined limits or are only prevented or rotated by the formation of sliding surfaces. Embodiments in which exercise is not excluded may also be considered.

The embodiments described above with reference to FIGS. 1 to 3 correspond not only to embodiments using ordinary components, but also to embodiments using calibration components.

4-6 an embodiment of a calibration component is shown. 4 is a front view of the upper component 3 formed as a calibration component. This component is formed thicker than the oppositely positioned edge near the edge 20 shown on the left in the figure. This component is symmetrically formed with respect to its front midplane such that the thick side 20 can be located on the side or midplane of the joint at the surgeon's choice.

5 shows a sagittal section of the upper component 3. This component is thickly formed wedge-shaped at the end 21 shown on the left in the figure. The upper side of this component is formed symmetrically with respect to the front face. The thick end may thus be placed forward or backward within the joint at the surgeon's choice. The wedge angle 22 between the upper fixed surface 23 and the lower sliding surface 7 represents a range of 5 ° in both embodiments.

6 shows the sagittal section of the calibration intermediate 5. Its lower side 16, which is formed as a sliding surface, has an overall directional structure which extends approximately parallel to the auxiliary line 24 drawn to represent the wedge angle 19 near the upper sliding surface 15. In this case, it is assumed that the line 24 in the ordinary middle portion extends parallel to the entire direction of the lower side 16. In order to identify the shape of the middle wedge, comparison with the usual components of the prosthesis system is always the standard.

It is not necessary to limit the calibration for each one component. Rather, the calibration component can be used for the intermediate component as well as for the upper component. Figure 1 illustrates this possibility.

If the surgeon has implanted the lower component 4, the surgeon may use a suitable instrument to determine whether or not the ablated surface 25 of the tibia has normally advanced to the lower component 4 in the tensioned side ligament. You can check whether this is necessary. In the latter case, the physician decides whether or not the corrective component should be chosen for both the upper component or the intermediate and how strong each wedge shape should be and in what direction. In addition, when the upper component 3 is inserted, corresponding measurements are possible. You can then decide whether to use the calibration component as an intermediate part.

FIG. 7 shows the assembly of the upper component 3 consisting of the standard part 25 and the wedge part 26. Since the standard part 25 forms the fixing element 8, a wedge part 26 can be formed more simply, which can be used at various wedge angles in a plurality of embodiments. The two parts can be connected to each other in any known manner. For example, they can be screwed together. Furthermore, complementary and interlocking protrusions and receptacles can be provided, allowing the two parts to be inserted into one another without virtually wasting.

Claims (6)

An internal prosthesis used to replace the ankle joint, the lower component 4 connected to the talus 2, forming the upper sliding surface 10, and the lower sliding surface 7, forming an ablation surface of the tibia ( Two sliding faces 15 interacting with the upper component 3 including the upper connecting face 23 and the sliding faces 7 and 10 of the upper and lower components 3 and 4 to be connected with 25. An internal prosthesis consisting of an intermediate portion comprising: 16) The upper component 3 is wedge shaped in the sagittal section between its lower sliding face 7 and its upper connecting face 23 and / or the intermediate part 5 is sagittal between its sliding faces 15, 16. An internal prosthesis in the form of a wedge in a section or front section. 2. The internal prosthesis according to claim 1, wherein the sliding surfaces (10, 16) which interact on the lower component (4) and the intermediate part (5) interact in a virtually rotatable manner with respect to the longitudinal axis. 2. The internal prosthesis according to claim 1, wherein the sliding surfaces (7, 15) which interact on the upper component (4) and the intermediate part (5) interact rotatably about the longitudinal axis. The internal prosthesis of claim 1, wherein the wedge angle is between 1 ° and 16 °. 5. The internal prosthesis according to claim 1, wherein the wedge-shaped component 3 consists of a wedge part 26 and a standard part 25 which can be used at various wedge angles. . An internal prosthesis system used to replace the ankle joint, the lower component 4 connected to the talus 2, forming the upper sliding surface 10, and the tibial component 1, forming a lower sliding surface 7. Two sliding interactions with the upper component 3 including the connecting surface 23 and the sliding surfaces 7 and 10 of the upper and lower components 3 and 4 for connection with the ablation surface 25 of the An internal prosthesis consisting of an intermediate part 5 comprising faces 15, 16, wherein the system comprises a normal upper component and an intermediate part, in which the upper and lower parts of the intermediate part are substantially entirely parallel, The system comprises a calibration element exchangeable for the normal upper component 3, which calibration element is formed in the form of a wedge at the sagittal and / or front side between its upper and lower sides 7, 23 and / or usually A calibrated intermediate part which is interchangeable with respect to the intermediate part 5 of, wherein the calibrated intermediate part is wedge-shaped in comparison to the normal intermediate part 5 in the sagittal plane between its entire surface 15 and its lower side 16. Features an internal prosthesis system.

Images