WO2000004885A2

WO2000004885A2 - Joint prosthesis system

Info

Publication number: WO2000004885A2
Application number: PCT/EP1999/005196
Authority: WO
Inventors: Emmanuel Anapliotis
Original assignee: Merete Management Gmbh
Priority date: 1998-07-21
Filing date: 1999-07-20
Publication date: 2000-02-03
Also published as: AU5618999A; WO2000004885A8; EP1098612A2; DE19833791A1; WO2000004885A3

Abstract

The present invention relates to a joint prosthesis system (50) that comprises a prosthesis rod (40), a ball joint (30), a cup-like adapter (20) which can be inserted between the rod and the ball joint and which comprises an opening (21) at the bottom (22), as well as a rod-shaped instrument for detaching the adapter from the neck of the prosthesis rod or from the reception cap of the ball joint. This instrument (1) includes a rod that comprises two parts (3, 5) and which is fitted with a first and a second means (9, 12) at its summit so that, during the relative displacement of the rod members, a tensile-strength or axial-compression component can be generated for gripping the inner or outer side (22.1, 22.2) of the bottom of the adapter and for detaching said adapter (20).

Description

Joint prosthesis system

The invention relates to a joint prosthesis system with a prosthesis shaft having a conical neck, with a joint ball which has a conically shaped receptacle, with a cup-like adapter which can be inserted between the prosthesis shaft and joint ball and has an opening in its base, the outer contour of the inner contour of the joint ball holder and whose inner contour corresponds to the outer contour of the cone-shaped neck and with a shaft-shaped tool for releasing the adapter from the neck of the prosthesis shaft or from the joint ball receptacle.

From the European patent application EP-0 498 518-1 a joint prosthesis system is known which comprises a prosthesis socket with a conical neck, an articulated ball with a conically shaped receptacle, a cup-like intermediate piece which can be used between the prosthesis socket and the jointed ball and a tool for releasing the Has intermediate piece from the neck of the prosthesis shaft or from the joint ball. The intermediate piece is essentially cup-shaped, its outer contour corresponding to the inner contour of the joint ball receptacle and its inner contour corresponding to the outer contour of the conical neck. In the area of the end face of the adapter which forms an adapter, a continuous threaded bore is provided, into which the shank of the tool, which is provided with an external thread at at least one end, can be screwed. A handle is provided at the other end of the tool shank to initiate the appropriate torque. The length of the external thread of the tool shank is greater than the length of the threaded bore plus the distance of the end face of the intermediate element from the end face of the prosthesis neck opposite this or the inner surface of the joint ball, so that the shank has a force effect for loosening the screw by screwing it into the end face of the intermediate piece Intermediate piece triggers.

The known solution has the disadvantage that the threaded shaft provided for generating the force releasing the adapter-shaped intermediate piece can be connected to the adapter to be released only with difficulty under operating conditions. In addition, the handling of the tool is very uncomfortable, since in particular no elements are provided with which the tool can be held in an optimal position with respect to the introduction of force into the respective prosthesis part.

Such properties hinder and complicate a surgical procedure considerably, which leads to a stressful extension of the operation for the patient and possibly also to complications when performing the operation itself.

Starting from the shortcomings of the prior art, the invention is therefore based on the object of specifying a joint prosthesis system of the type mentioned at the beginning, the tool of which is designed in such a way that it is particularly convenient under operating conditions to initiate a reaction force required to release the prosthesis parts handle.

The object is achieved by a joint prosthesis system of the type mentioned, in which the tool has a two-part shaft, at the tip of a first and a second, through the opening at the bottom of the adapter into a space between the adapter base and neck of the prosthesis shaft or Means which can be inserted into the adapter base and the joint ball receptacle are provided such that an axial tensile or compressive force component acting on the inside or outside of the adapter base can be generated when the shaft parts move relative to one another. The invention includes the finding that the manageability of a surgical tool for releasing an adapter from parts of a hip or shoulder joint prosthesis under operating conditions can be considerably improved if the required positive and positive connection between the tool and the adapter is quick and essentially can be produced by a handle.

Particularly advantageous in the invention is the fact that with this very easy-to-produce connection between the tool and the adapter, the reaction forces remain essentially within the arrangement formed by the conical prosthesis neck or the joint ball, the adapter and the tool and not when the connection between them is released Adapters and the respective prosthesis part must be taken over manually by the person operating the tool.

In a preferred embodiment of the invention, a tool with a two-part shaft is provided for the prosthesis system. The tool shaft has a hollow cylindrical guide sleeve as the first shaft part and a cylindrical mandrel as the second shaft part, which completely penetrates the guide sleeve and is arranged to be movable in the axial direction relative to the guide sleeve. If the shaft tip is brought into active contact with interconnected prosthesis parts of the joint prosthesis system, this relative movement can generate force effects on the shaft tip in a simple and at the same time advantageous manner which can be used to loosen the interconnected prosthesis parts.

The tool, which has a two-part shaft, is inserted with the shaft tip through an opening in the bottom of the adapter into a free space between the adapter base and neck of the prosthesis socket or adapter base and joint ball receptacle, so that a relative movement between the shaft parts results in a first part of the shaft of the Tool provided means is supported on the prosthesis socket or in the joint ball receptacle and by a second means provided on the other shaft part of the tool an axial pull, which acts on the inside or outside of the adapter base and releases the adapter from the prosthesis socket or the joint ball - or pressure force component is effective.

According to an advantageous development of the invention, the tool a handle on which the guide sleeve is secured against rotation and secured against axial displacement. The mandrel, which penetrates both the guide sleeve and the grip piece axially, has at its end facing away from the shaft tip a handle, preferably designed as a toggle, in order to rotate the mandrel with relatively little effort and at the same time to be able to introduce the torque into the corresponding arrangement , which generates the force required to loosen the prosthesis parts.

According to a preferred embodiment of the invention, the tip of the dome is provided as the first means, which is supported on the neck of the prosthesis socket or in the joint ball receptacle. At its free end, which is led out of the handle of the tool, the guide sleeve preferably has two peg-shaped projections which extend outward in the radial direction and form the second means. The projections, in cooperation with the mandrel tip, ensure a non-positive and positive connection of the guide sleeve to the adapter base, which is necessary for introducing the force component that releases the connected prosthesis parts.

The opening provided in the bottom of the adapter is designed as a bore which is widened to the edge of the bottom by two essentially slot-shaped recesses arranged diametrically opposite one another. Its shape and size essentially correspond to the cross-sectional area of the guide sleeve in the area of the projections.

Thus, the peg-shaped projections at the end of the guide sleeve can be brought into engagement by a 90 ° rotation of the tool about its longitudinal axis with the inside or outside surface areas next to the opening in the adapter base, thereby blocking a movement of the tool opposite to the direction of insertion of the shaft tip is.

To generate the relative movement between the mandrel and the guide sleeve for releasing the prosthesis parts connected to one another, a drive is provided which, in accordance with the preferred embodiment of the invention, is formed by coupling two threads. For this purpose, the guide sleeve has a section with an internal thread, which is in operative engagement with an external thread, which is provided on a correspondingly long section of the dome. When the guide sleeve is stationary, ie held by means of the handle of the tool, the mandrel is rotated axially. If the mandrel tip reaches with the shaft inserted into the free space, when the dome is rotated further using the knob-shaped handle over the pin-shaped projections of the guide sleeve lying against the adapter base, the adapter of the prosthesis socket engages on the inside or outside of the adapter base or generated from the joint ball tensile or compressive force component.

By means of the handle, the tool can be easily held in a position in which the axis of the joint prosthesis system is aligned with the longitudinal axis of the tool. At the same time, the handle and toggle ensure easy handling of the tool when force is applied to loosen the prosthesis parts.

According to an additional development of the invention, the cup-shaped adapter has an annular bead on the outside. The annular bead on the rim of the cup, which is preferably produced by flaring the wall of the cup-shaped adapter, makes it easier to detach the adapter from the prosthesis socket using a conventional knockout tool. This is necessary, for example, if the joint ball is particularly tight and cannot be separated from the adapter by using such a striking tool or if the striking tool cannot be used for medical reasons.

According to an advantageous variant of the invention, an adapter is provided which has an eccentrically arranged receiving area for the conical neck of the shaft part. As a result, the longitudinal axis of the tool does not coincide with the longitudinal axis of the adapter and the tool can also be used to loosen the parts of a shoulder joint prosthesis.

Other advantageous developments of the invention are characterized in the subclaims or are shown below together with the description of the preferred embodiment of the invention with reference to the figures. Show it:

1 shows a preferred embodiment of the tool of the joint prosthesis system according to the invention in a longitudinal section,

2 the tool shown in Figure 1 in a view from the side, 3 shows an advantageous embodiment of an adapter of the joint prosthesis system according to the invention in a top view from the bottom,

4 shows the view of a section along the line A ... A according to FIG. 2,

5 and 5a an advantageous embodiment of the joint prosthesis system according to the invention in partial sectional view,

6 and 6a another embodiment of the joint prosthesis system according to the invention in a partial sectional view, and

Fig. 7 shows a further embodiment of the joint prosthesis system according to the invention in partial sectional view.

The tool 1 shown in FIGS. 1 and 2 in a longitudinal sectional view or in a side view of a joint prosthesis system having differently dimensioned joint balls, prosthesis shafts and adapters is required to loosen an adapter which, while compensating for length tolerances for a connection between the joint ball and the cone-shaped neck of the prosthesis stem is inserted (compare positions 20, 30, 40, 41, in Figures 3, 4, 5, 5a, 6 and 6a).

The tool 1 has a handle 2 made of plastic, in which a hollow cylindrical guide sleeve 3 is inserted. A cylindrical mandrel 5 is inserted into the guide sleeve, which is connected to the handle 2 in a manner secured against rotation and secured against axial displacement, which can be moved in the axial direction relative to the guide sleeve 3.

To generate the relative movement of the mandrel 5 with respect to the guide sleeve 3, a threaded coupling 6 is provided, the guide sleeve 3 having a section which has an internal thread 7 and which engages with a section of the mandrel 5 which has an external thread 8.

By rotating the mandrel 5 in a tool 1 held manually on the handle 2, the tip 9 of the mandrel 5 is moved in or out along the axis 11, depending on the direction of rotation, from the free end 10 of the guide sleeve 3. Via a toggle 14, which is fastened to the end 15 of the mandrel 5 protruding from the handle 2 by a rivet 1 6, a sufficient torque to move the mandrel.

The free end 10 of the guide sleeve 3 carries two pins 1 2 of the same size on the outside, which extend radially outwards and are arranged diametrically to one another. The pin ends 1 3 are rounded.

The cross-sectional area of the guide sleeve 3 in the region of the pins 1 2 thus has the same shape as the opening 21 in the bottom 22 of the adapter 20 of the joint prosthesis system according to the invention shown in FIGS. 3 and 4 in a longitudinal sectional view or plan view.

The opening 21 is composed of a circular bore 23, the diameter of which corresponds to the outer diameter of the free end 10 of the guide sleeve 3 of the tool 1, and two equally large, diametrically opposed recesses 24, each of which has a radial slot parallel to the boundary edges of the bore 23 extend outwards to the wall 25 of the adapter 20.

Through this opening 21, the tool 1 can be guided with the free end 10 of its guide sleeve for releasing the adapter 20 stuck in the joint ball 30 after the joint ball 30 has been removed from the conical neck 41 of the prosthesis shaft 40 of the joint prosthesis system 50 by mechanical knocking out is, as shown in Figures 5 and 5a in partial sectional view.

The annular bead 26 on the outside of the rim, which is preferably produced on the outside by flanging the wall 25 of the cup-shaped adapter 20, facilitates the detachment of the adapter from the prosthesis socket using a conventional removal tool. This is necessary, for example, if the joint ball is particularly tight and cannot be separated from the adapter by using such a striking tool.

In order to facilitate the introduction of the free end 10 of the guide sleeve 3 into the free space 31 between the bottom region 32 of the joint ball receptacle 33, the opening 21 in the adapter base has a certain excess in relation to the dimensions of the free end 10 of the guide sleeve 3.

After the tool 1 with the free end 1 0 of the guide sleeve 3 so far has been guided through the opening 21 in the adapter base 22, that the pins 1 2 at the free end 1 0 of the guide sleeve 3 are completely in the space 31 between the adapter base 22 and the joint ball 30, by pivoting the tool 1 about the axis 1 1 accordingly the direction of arrow 28 by 90 ° to the right or left reaches that the pins 1 2 extend above the surface areas 22.1 and 22.2 of the adapter base 22.

Unscrewing the mandrel 5 by a rotational movement in the direction of arrow 28 with the guide sleeve 3 being fixed by holding the grip 2 of the tool 1 leads - when the tip 9 of the mandrel 5 has reached the bottom region 32 of the joint ball receptacle 33 - to the effect of a compressive force on the adapter base 22, which releases the adapter 20 from the conical seat in the joint ball receptacle 33.

By selecting the thread pitch, a sufficiently large torque can be introduced into the arrangement by the rotary movement of the mandrel 5 via the toggle 14 at the mandrel end 1 5 protruding from the handle 2 of the tool 1, in order to obtain a torque required for releasing the adapter 20 from the joint ball 30 Generate compressive force.

FIGS. 6 and 6a show a partial sectional view of a joint prosthesis system 50 'or a prosthesis shaft 40' separated from the joint ball 30 ', on the conical neck 41' of which an adapter 20 'to be released by the tool 1 is seated.

To release the adapter 20 ', the two-part tip of the shaft of the tool 1 formed from the guide sleeve 3 and the mandrel 5 is pushed so far through the opening 21' in the bottom 22 'of the adapter that both the pins 1 2 are at the free end of the guide sleeve 3 and the tip 9 of the mandrel 5 are located within the free space 31 'between the neck 41' of the prosthesis socket 40 'and the bottom 22' of the adapter 20 '.

After a pivoting movement of the tool 1, indicated by arrow 27, about its longitudinal axis, which corresponds to the longitudinal axis 11 of the prosthesis system 50 ', by approximately 90 °, the pins 12 are located under the areas 22.3' and 22.4 'of the inside of the adapter base 22 '.

By turning the mandrel 5 in the direction of arrow 28, the mandrel tip moves 9 as far down until it is supported on the neck 41 'of the prosthesis socket 40', the pins 1 2 come into active contact with the inside of the adapter base 22 'and the shaft tip of the tool 1 is clamped in the free space 31'. By further turning the mandrel 5, a tensile force component acting on the bottom 22 'of the adapter 20' is generated which releases the adapter 20 'from the conical seat of the prosthesis socket 40'.

By selecting the thread pitch, a sufficiently large torque can be introduced into the arrangement by the rotary movement of the mandrel 5 via the toggle 14 at the mandrel end 1 5 protruding from the handle 2 of the tool 1 in order to release the adapter 20 from the neck of the stem prosthesis 40 '. generate the required tractive force.

The tool 1 can be comfortably held by the handle 2 in the position in which the longitudinal axis of the tool is aligned with the longitudinal axis 11 of the prosthesis system 50 or 50 '.

FIG. 7 shows, in a partial sectional illustration, a shaft part 40 ″ separated from the joint ball for a shoulder joint, on whose conical neck 41 ″ an adapter 20 ″ to be released by the tool 1 is seated.

Due to the anatomical features of the shoulder joint, the adapter 20 "has an eccentrically arranged receiving area for the conical neck of the shaft part. The longitudinal axis 11 of the tool 1 therefore does not coincide with the longitudinal axis 11" of the adapter 20 ".

The opening 21 "in the adapter base 22" is designed as shown in FIG. 4, so that a force similar to that in FIG. 4 can be generated by the tool 1 inserted into the free space 31 "between the adapter base and the shaft part on the base portions 22.3" and 22.4 " the explanations for Figures 5, 5a, 6 and 6a explained.

The embodiment of the invention is not limited to the preferred exemplary embodiments specified above. Rather, a number of variants are conceivable which make use of the solution shown, even in the case of fundamentally different types.

Claims

1 . Joint prosthesis system (50, 50 ', 50 ") with a prosthesis shaft (40, 40', 40) having a conical neck (41, 41 ', 41"), with a joint ball (30, 30') which is conical Receptacle (33, 33 ') has, with a cup-like adapter (20, 20', which can be inserted between the prosthesis socket and the joint ball and has an opening (21, 21 ', 21 ") in its base (22, 22', 22"), 20 "), whose outer contour (25.1) corresponds to the inner contour of the joint ball receptacle and whose inner contour (25.2) corresponds to the outer contour of the conical neck and with a shaft-shaped tool (1) for releasing the adapter from the neck of the prosthesis socket or from the joint ball receptacle, characterized in that the tool (1) has a two-part shaft (3, 5), at the tip of which a first and a second, through the opening (21, 21 ', 21 ") at the bottom (22, 22', 22") of the adapter ( 20, 20 ', 20 ") in a free space (31, 31', 31") between the adapter base and neck (41, 41 ', 41 ") of the prosthesis socket (40, 40', 40") or adapter base and joint ball receptacle (33, 33 ') insertable means (9, 12) are provided such that an axial, at the The inside or outside (22.1, 22.2, 22.3 ', 22.4', 22.3 ", 22.4") of the adapter base acting on the tensile or compressive force component can be generated.

2. Joint prosthesis system according to claim 1, characterized in that the shaft parts (3, 5) by a mechanical drive (6) relative to each other on the same axis (1 1) are arranged movable.

3. Joint prosthesis system according to claim 2, characterized in that the drive (6) has a threaded coupling (7, 8) between the shaft parts (3, 5).

_4- joint prosthesis system according to claim 2 or 3, characterized in that the first means (9) supporting shaft part is designed as a mandrel (5) which in a shaft part designed as a guide sleeve (3) carrying the second means (12) is movable in the axial direction such that the mandrel tip (9) moving out of the free end (10) of the guide sleeve (3) on the prosthesis neck (41, 41 ', 41 ") or on the joint gel receptacle (33, 33 ') and that the second means (1 2) arranged on the outside at the free end (10) of the guide sleeve (3) with the inside or outside (22.1, 22.1, 22.3', 22.4 ', 22.3 ", 22

4 ") of the adapter base (22, 22 ', 22") is operative to transmit a tensile or compressive force.

5. Joint prosthesis system according to claim 4, characterized in that the means for power transmission are designed as radially outwardly extending pin-shaped projections (1 2) of the same size and diametrically opposed to each other.

6. joint prosthesis system according to claim 4 or 5, characterized in that the free end (10) of the guide sleeve (3) in the region of the force transmission means (1 2) has a cross-sectional area which the opening (21, 21 ', 21st ") in the adapter base (22, 22 ', 22") corresponds.

7. Joint prosthesis system according to one of the preceding claims, characterized by an adapter (20, 20 ', 20 "), the bottom (22, 22', 22") of which is designed as a bore (23) opening (21, 21 ', 21 "), which is expanded by two diametrically opposite, essentially slot-shaped recesses (24) up to the edge of the base (22, 22 ', 22").

8. joint prosthesis system according to one of claims 4 to 7, characterized in that the tool (1) has a grip piece (2) on which the guide sleeve (3) is secured against rotation and secured against axial displacement, and the mandrel (5) axially penetrates both the guide sleeve (3) and the handle (2).

9. prosthetic joint system according to claim 8, characterized in that the guide sleeve (3) is inserted into the handle (2) and fixed by a transverse to the longitudinal axis (1 1) of the shaft (3, 5) extending pinning (4) .

10. Joint prosthesis system according to one of claims 7 to 9, characterized in that a handle (1 4) is arranged on the end of the mandrel (1 5) projecting from the handle (2).

1 1. Joint prosthesis system according to claim 10, characterized in that the handle is designed as a toggle (14) extending transversely to the shaft axis (1 1).

1 2. Joint prosthesis system according to one of the preceding claims, characterized in that an externally arranged annular bead (26, 26 ') is provided at the edge of the opening of the adapter (20, 20') facing away from the bottom (22, 22 ').

13. Joint prosthesis system according to one of the preceding claims, characterized in that the longitudinal axis (1 1) of the tool (1) and the longitudinal axis (1 1 ") of the adapter (20") are arranged eccentrically to one another.