KR101044893B1 - Ankle-joint endoprosthesis - Google Patents

Abstract

The present invention relates to an internal prosthesis used to replace the ankle joint and includes a lower component (4) connected to the talus (2), an upper component (3) connected to the tibia (1) and a lower and upper component. It consists of an intermediate portion 5 to form a slip joint with. To compensate for anatomical or surgical irregularities, an intermediate portion 5 in which the sagittal sections are wedge-shaped is provided. The upper component 3 can likewise be wedge shaped in the frontal or sagittal segment.

Lower component, upper component, middle part, slip joint, sagittal section

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, pamphlet 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 and LM directions. 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 an imbalance between an anatomical or surgical situation on the one hand and a prosthesis on the other hand.

The solution according to the invention is shown in the characterizing part of claims 1 or 6. According to the invention the intermediate and / or tibial component is formed in the form of a wedge. If an uncorrected conventional prosthesis is used, if the surgeon finds that the ligament tension is different, the surgeon can compensate for this by using a corrective component having a wedge shape in front. The thicker side of the wedge shaped calibration plate is placed on the side where ligament tension may be insufficient when using conventional components. If the surgeon recognizes that the tibial resection is not perpendicular to the tibial direction, or for some other reason that the faces of the prosthesis do not extend perpendicular to the tibial axis, the surgeon may A calibrating component can be inserted. If the lower sliding surface of the upper component wants to have a specific direction with respect to the tibial or load direction, the surgeon will generally use the tibial component designed as a corrective component. In contrast, however, when the direction of the tibial resection is correct and the anatomy of the foot is taken into account, the surgeon prefers an intermediate designed as an orthodontic component.

The present invention described above does not relate to the design of the wedge-shaped intermediate portion at the front, which is intended by the 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 because the upper sliding surface as well as the lower sliding surface is flat or almost flat. In the sagittal plane, it is important to compare the midsection with the midsection to determine any wedge shape. In addition, the overall direction of the lower sliding surface as well as the direction of the upper sliding surface which is the substantially planar portion of the intermediate part is simply determined. If the intermediate part becomes thicker in the forward or rearward direction than the conventional intermediate part, in the sense according to the invention the intermediate part is in the form of a wedge in the sagittal plane.

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 in the sagittal plane or front face may not be the wedge shape in the front face or sagittal plane.

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

In order that the wedge-shaped direction of the middle part cannot be changed by the rotation of the middle part about the longitudinal axis, the direction is an interactive sliding surface designed (eg cylindrically) to determine either direction by the tibia or by the tibia. It is preferable to be forcibly fixed by a pair of. 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. To reduce the costs associated with this, the calibration component is preferably designed to be as simple as possible. It may therefore be desirable to assemble with standard and wedge parts that remain constant at all times. Standard parts are provided in only one construction. Only wedge shapes need to be provided in various variations. This is particularly suitable when the upper component is used as the calibration component and the standard part 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 talisman 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 11, which is present in the direction of relative movement of the intermediate part in the bending and unfolding motions. 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 lower sliding face 16 designed to complement the sliding face 10 of the upper component 15 and the lower component 4, which is a plane fitted to the sliding face 7. The lower side of the middle portion has a groove 17 for receiving the rib 11. The intermediate part 5 is thus guided along the side with respect to the lower component 4. Only bending and stretching movements 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 complementary forms of the sliding surfaces 10 and 16, and by the ribs 11 interacting with the grooves 17, the intermediate part 5 is not rotatable about the longitudinal axis with respect to the ankle component 4. Also, the direction is fixed by the direction of the lower component. While the illustrated embodiment completely excludes this rotational movement about the longitudinal axis between the lower component and the intermediate part, rotational movements are allowed within predetermined limits, limited only by the design of sliding surfaces or excluded from rotational movements. Embodiments that are not considered may also be considered.

The embodiments described above with reference to FIGS. 1 to 3 correspond to embodiments using calibration components as well as to embodiments using conventional components.

4-6 an embodiment of a calibration component is shown. 4 is a front view of the upper component 3 designed 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 designed symmetrically about 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 designed 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 designed as a sliding surface, has a direction which extends approximately parallel to the auxiliary line 24 drawn in order to represent the wedge angle 19 near the upper sliding surface 15 as a whole. In this case, it is assumed that the line 24 in the usual intermediate portion extends parallel to the entire direction of the lower side 16. An important factor in determining the middle wedge shape is always a comparison with the conventional components of the prosthesis system.

Calibration does not need to be limited to only one component in each case. Rather, the calibration component can be used for the intermediate component as well as for the upper component. Figure 1 illustrates this possibility.

As soon as the surgeon implants the lower component 4, the surgeon uses a suitable instrument to ensure that when the collateral ligament is tensioned, the resection of the tibia 1 extends normally relative to the lower component 4 or is corrected. You can check whether it 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 a fixing member (protrusion) 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 (8)

An internal prosthesis used to replace the ankle joint, the lower component 4 forming the upper sliding surface 10 and connected to the talus 2, and the lower sliding surface 7 forming a lower sliding surface 7 of the tibia 1 An upper component 3 comprising an upper connection surface 23 for connection with the ablation surface and two sliding surfaces which interact with the sliding surfaces 7 and 10 of the upper and lower components 3 and 4 ( An internal prosthesis consisting of an intermediate portion comprising 15, 16), The intermediate part 5 is wedge shaped in the sagittal section between its sliding surfaces 15, 16, The sliding surface (7, 15) interacting on the upper component (3) and the intermediate portion (5) is characterized in that the rotatable interaction about the longitudinal axis. 2. The internal prosthesis according to claim 1, wherein the sliding surfaces (10, 16) interacting on the lower component (4) and the intermediate part (5) interact rotatably about the longitudinal axis. delete The internal prosthesis according to claim 1, wherein the wedge angle (19, 22) is between 1 ° and 16 °. The internal prosthesis according to claim 1, wherein the wedge-shaped component (3) consists of a wedge part (26) and a standard part (25) with various wedge angles. The internal prosthesis according to claim 4, 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, a tibial component (1) forming a lower sliding surface (7) and a lower component (4) that forms an upper sliding surface (10) and is connected to the talus (2). An upper component 3 comprising a connection surface 23 for connection with an ablation surface of the two sliding surfaces interacting with the sliding surfaces 7, 10 of the upper and lower components 3, 4 ( An internal prosthesis consisting of an intermediate part 5 comprising 15, 16, wherein the system comprises an uncalibrated upper component and an intermediate part, the upper and lower parts of the intermediate part being in totally parallel system, The system includes a calibration element that is replaceable for an uncalibrated upper component (3) and the calibration element is wedge at the sagittal, front, or sagittal and front side between the upper side (7) and the lower side (23) of the calibration element. Or the system comprises a calibrated intermediate which is interchangeable with respect to the uncalibrated intermediate 5 and the calibration intermediate is not calibrated in the sagittal plane between the entire surface of the upper side 15 and the lower side 16 of the calibration intermediate. Wedge-shaped compared to the non-intermediate part 5, or both the calibration element and the calibration intermediate part of the system are wedge-shaped, An internal prosthesis system, characterized in that the sliding surfaces (7, 15) interacting on the upper component (3) and the intermediate part (5) interact rotatably about the longitudinal axis. An internal prosthesis used to replace the ankle joint, the lower component 4 forming the upper sliding surface 10 and connected to the talus 2, and the lower sliding surface 7 forming a lower sliding surface 7 of the tibia 1 An upper component 3 comprising an upper connection surface 23 for connection with the ablation surface and two sliding surfaces which interact with the sliding surfaces 7 and 10 of the upper and lower components 3 and 4 ( An internal prosthesis consisting of an intermediate portion comprising 15, 16), The upper component 3 is wedge shaped in the frontal section, sagittal section, or in the frontal and sagittal section between its lower sliding surface 7 and its upper connecting surface 23, The sliding surface (7, 15) interacting on the upper component (3) and the intermediate portion (5) is characterized in that the rotatable interaction about the longitudinal axis.

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