DE10119079C1 - Modular bone file or shaft implant has shaft of distal part received in channel of proximal part and clamped in required relative position by elastically expandible wall section - Google Patents

Abstract

The bone file (1) or shaft implant has proximal and distal parts (6,2) coupled together to allow their relative adjustment via a channel in the proximal part receiving a shaft of the distal part, provided with an end sleeve having an elastically expandible wall section and a cooperating clamp element, engaging the inside wall of the channel.

Description

The invention relates to a modular bone rasp with a proximal part and with a distal part Part and with coupling agents for detachable connection of the proximal part with the distal part.

Such a modular bone rasp is known for example from US-A-6,126,694. Derarti Grated bones allow the shape to be adjusted the bone rasp to the anatomical conditions, by using different proximal and distal parts can be combined. This makes it possible to To prepare the opening in a long bone that differently shaped endoprosthesis stems can be used, with this endoprosthesis Modular shafts made of differently shaped compos can be built up. The endoprosthesis sheep te are shaped essentially the same as that modular bone rasps, and from this Basically, the invention also relates to one in this way modular stem prosthesis.

With known modular bone rasps or The prostheses are often the individual parts via Ge winch connected, this is relatively cumbersome  Lich and also has the disadvantage that an accurate re relative fixation is difficult, especially in the outward direction look at a rotation of the components of the bone races pel or the stem prosthesis around an axis through the screw-in axis is determined. Then it must come duplicated indexing measures are provided, and the These, in turn, often do not allow the individual Components with the necessary fine division right relative to each other, but through the In dexwide only rough adjustments of the components relative to each other.

DE 199 26 391 C1 describes a multi-part prosthesis described in which the connection of the prosthesis socket parts is achieved by clamping clamping cones, which by means of Spannele elements can be clamped against each other with threads. Although one such construction works very well, is a relatively complicated one Construction necessary because special clamping cone parts are used have to.

It is an object of the invention to have a modular structure Bone rasp or stem prosthesis of the generic type Art so that the components quickly with connected to each other and then relative to each other can be set, allowing at the same time should be the relative position of in this way connected parts of the bone rasp or the shaft pro adjust these sensitively.

This task is done with a modular kno Chenasp or stem prosthesis of the description above NEN inventively solved in that the proxi paint a part from proximal to distal Canal has that the distal part one of its distal end insertable into the canal and fully inserted state end inside the channel has the holding shaft which in at its free end Form of a sleeve ends, the wall areas of which are elastic are expandable, and that in the proximal end of the Ka  nals one in the sleeve-shaped end of the holding shaft engaging and the wall areas of the sleeve widen and clamp against the inside of the channel the clamping element can be used.

With such a modular bone rasp or shaft prosthesis can the proximal part relative to the distal part are twisted sensitively, and the one once reached angular position can fi xiert that a clamping element in the sleeve of the Holding shaft is inserted. Thereby the wallbe richly expanded the holding shaft and against the inside of the channel clamped, the two parts the bone rasp or the stem prosthesis are on the against both rotation and one Secured pulling the holding shaft out of the channel.

It is advantageous if the clamping element has a coni rule, immersed in the sleeve clamping portion. Simply by pressing the clamping element into the sleeve the clamp fixation can thus be produced.

It when the clamping element in the proximal end of the channel is screwed. To Her position of the clamp connection, it is sufficient that Clamping element in the proximal end of the channel screw, the clamping element dips into the sleeve and pushing in the elastic wall areas outside against the inside of the channel.  

In particular, an external thread section that can be screwed into an internal thread of the channel, un indirectly proximal to the clamping section of the clamp connect mentes.

It is also convenient if the clamping element on his proximal end for a non-circular contact section Has turning tool. This can be, for example Outside polygon or an inner polygon known per se Be kind.

In a preferred embodiment, that the wall area of the sleeve on its outside ra dial protruding protrusions, which at complete protrusions pushed into the channel reach behind the inside of the channel so that the Holding shaft against pulling out of the channel chert is, and that the projections on the wall area of the Sleeve can be moved elastically radially inwards, until it pulls out of the holding shaft the channel on the protrusions on the inside of the Ka nals can slide past.

This makes it possible for the two parts of the bones rasp or the stem prosthesis very quickly to connect, it is sufficient to insert the holding shaft into the Insert the canal until the tabs of the holding sheep tes the protrusions on the inside of the channel ela reach behind. Pulling out the holding sheep tes is still possible in this situation, required but overcoming a certain holding force, d. H.  the two parts of the bone rasp are on this Way releasably held together. With this type the connection allows the proximal to rotate freely Part of the bone rasp or the stem prosthesis relative given to the distal part, so that the two parts in who adjusted the desired way relative to each other that can.

In particular, it can be provided that the front cracks-bearing wall area of the sleeve elastically radial is bendable inwards. By elastic bending of this wall area inwards thus become the front jumps into a position that slides past the projections of the channel and thus pulling it out of the two parts of the bone rasp or the shaft pro enable these.

It is particularly favorable if the wall area of the sleeve se through axially parallel incisions in elastic ver bendable tongues is divided. In particular can these elastic tongues radially at their free ends protrusions protruding outwards, which in the be wrote out a detachable plug-in connection form, which maintains the free rotatability.

The protrusion can go through on the inside of the channel a step-widening of the canal in the proximal Direction are formed, these stepped Er extension is preferably beveled.  

It is also convenient if the protrusions on the wall area the sleeve has a bevelled sliding surface, so that pulling out the holding shaft the channel is made possible in which the projections of the Slip the wall area onto the projections of the channel and thereby be moved elastically inwards.

In a modified embodiment of the invention it is provided that the inside of the channel in the Several projections in the longitudinal direction at a distance from one another for the projections of the holding shaft and that between distance between the proximal and distal parts element is arranged, which the insertion depth of the Holding shaft limited in the channel so that the Projections on the holding shaft one of the distally displaced Engages behind projections. Become distal part and proximal part assembled without spacer, the projections on the holding shaft engage behind the proxi projections on the inside of the channel if, on the other hand, a spacer element is used, the Holding shaft not pushed so deep into the channel, so that the protrusions on the holding shaft then protrusions opposite the inside of the channel, which in di staler direction are shifted. That way it is possible, a bone rasp or a stem prosthesis build with greater length. Basically you can two such projections spaced apart in the Channel will be provided, then only a single Di stamping element used, the length of the distance this corresponds to both projections, or there will be several Projections provided on the inside of the channel,  then spacer elements of different lengths are too use that on the distances of the protrusions on the Inside of the channel are matched.

The spacer can in particular on the Hal be pushed on spacer sleeve.

It is then still according to the location of the front jumps in the channel and according to the length of the Di punching element of different lengths seen so that the clamping portion of the clamping element always lies in the area in which the protrusions of the Holding the projection on the inside of the Ka reach behind.

In a preferred embodiment of the invention provided that the clamping element one in the sleeve of the Immersed holding shaft, an elastic displacement Prevention of the projections of the holding shaft inwards blocking block, but which carries the wall areas of the sleeve not jamming against the inside of the channel shifts. If this blocking section in immerses the sleeve, the wall areas of the sleeve and thus the worn, radially outwards protrusions no longer elastic inwards be moved so that it is no longer possible the distal part of the rasp or the stem pull the thesis out of the proximal part. The free In this case, rotatability is also retained th.  

It is advantageous if the blocking section immediately distal to the clamping section of the clamp mentes connects, in particular the clamping section be formed by a circular cylindrical pin. If the clamping element is not completely in the channel is screwed in, the blocking section is immersed in the sleeve and prevents elastic displacement Exercise of the wall area of the sleeve and the held on projections inside, but without the free ver hinder rotatability. If, however, the clamping element is screwed in further, the conical lies down Clamping section to the inside of the wall area of the Sleeve and thus elastically expands the sleeve where with the wall areas clinging to the inside of the Ka nals are created, there will also be a definition of the two parts of the bone rasp or the shaft pro against relative rotation.

In a preferred embodiment of the invention further provided that the proximal part and distal part wear display elements on which the Win position around the through the longitudinal axis of the channel de defined axis of rotation of the distal part relative to the proximal part is readable. For example, the Display elements by a scale on a part and a Marking element to be formed on the other part. Thereby the user can easily change the angular position read that when using curved distal parts is important. Depending on the anatomical conditions the bend may be slightly different directed, and this inevitably results in an under  different angular position of the distal part relative to the proximal part, if the parts are in a rasp who can be freely rotated into the bone cavity the. After insertion, the free rotatable cancel speed by jamming the two parts, and then the user can display the win on the display element Read the position of the two parts relative to each other and this angular position on a stem prosthesis transferred, which takes place after removal of the rasp this is to be inserted into the bone cavity. The In this way, the stem prosthesis can exactly match the anatomy conditions.

The following description of preferred embodiment forms of the invention is used in connection with the Drawing of the detailed explanation. Show it:

1 is a side view of a modular of a per imum portion and a distal portion constructed bone rasp in the assembled state.

Fig. 2 is a partial sectional view similar to Figure 1 before inserting the clamping element.

Fig. 3 is an enlarged sectional view of the proximal portion of the bone rasp with screwed clamping element;

Fig. 4 is a view similar to FIG. 3 with display elements for determining the angular position of the distal part relative to the proximal part and

Fig. 5 is a view of a rasp similar to that of Fig. 2 with two spaced projections on the proximal part and with a spacing element between the distal part and the proximal part.

The invention is described below using the example of a modu lar built bone rasp discussed, it understands but that the invention in the same way one of essentially the same modular design Shaft prosthesis can be used. This under differs from a bone rasp at best through that the rasp teeth are missing and through smooth Surfaces are replaced. The basic structure and especially the connection of the distal and proxi paint part but are also in a stem prosthesis in the same way as in the following described bone rasp.

The bone rasp 1 shown in the drawing summarizes a distal part 2 in the form of a rectilinear, circular cylindrical shaft 3 , which is shown in the drawing with a smooth outer wall, but which, depending on the loading, may be occupied with rasp teeth.

The shaft 3 carries at its proximal end concentrically to itself a likewise circular cylindrical, elongated holding shaft 4 , at the transition from the shaft 3 into the holding shaft 4 an annular step 5 is formed, which extends transversely to the longitudinal direction of the distal part 2 .

The bone rasp 1 further comprises a proximal part 6 with a shaft-shaped rasp region 7 and a laterally projecting, from distal to proximally widening extension region 8 , which has a coupling element 9 for a handle on its proximal end most distant from the rasp region 7 is not shown in the drawing. The rasp 7 is completely surrounded in the lower part of blade-shaped Raspelrippen 10, at the distal end of the rasp portion 7 the Raspelrippen 10 surrounded in this area, only U-shaped, ie they end at the neck area. 8

In addition, the edge 11 of the attachment area 8 which is distant from the rasp area 7 and which runs in an arc from the distal rasp area 7 to the coupling element 9 is covered with rasp teeth 12 .

The shaft-shaped rasp region 7 is penetrated by a continuous channel 13 with a circular cross-section, which emerges at the distal end of the rasp region 7 in a central manner therewith. At its proximal end, the channel 13 widens at a beveled ring step 14 , and an internal thread 16 is incorporated at the proximal end of the enlarged area 15 that is created in this way.

The holding shaft 4 of the distal part 2 of the Knochenras pel 1 is provided at its free, proximal end with a circular blind hole 17 in cross section, so that the holding shaft 4 is sleeve-shaped in this proximal end region. The relatively thin wall areas are separated from each other by axially parallel longitudinal slots 18 and form adjacent, elastically radially outward and radially inward from bendable tongues 19 . These carry at their free ends radially outwardly projecting projections 20 which each have an oblique sliding surface 21 and 22 at their lower, distal end and at their upper, pro ximal end.

The outer diameter of the holding shaft 4 corresponds to the inner diameter of the channel 13 , it is only slightly smaller, while the outer diameter of the projections 20 with undeformed tongues 19 is larger than the inner diameter of the channel 13 .

It is possible to insert the holding shaft 4 from the distal end of the channel 13 into it, the sliding surfaces 22 of the projections 20 sliding on the distal edge of the channel 13 and elastically bending the tongues 19 radially inwards, so that the projections 20 into the slightly smaller cross section of the channel 13 can be pushed. As soon as the projections 20 slide past the ring step 14 of the channel 13 when inserting the holding shaft 4 into the channel 13 , the tongues 19 spring radially outward again, so that the projections 20 engage behind the ring step 14 , as is shown in FIGS . 2 and 3 is shown.

The dimension of the holding shaft 4 in the longitudinal direction is chosen so that the ring step 5 of the distal part 2 les strikes at the distal end of the rasp region 7 as soon as the projections 20 behind the ring step 14 fengrei. This positioning is shown for example in Fig. 2.

The outer diameter of the shaft 3 of the distal part 2 and the rasp area 7 are in the area of the ring step 5 and in the area of the distal end of the rasp area 7 approximately the same size, so that a continuous transition from the shaft 3 into the rasp area 7 occurs.

If the distal part 2 with the holding shaft 4 is inserted into the channel in the manner described, the distal part 2 and the proximal part 6 are connected to one another in such a way that the projections 20 engage behind the ring step 14 , but it is easily possible, to rotate the distal part 2 relative to the proximal part 6 about the longitudinal axis of the channel 13 . In addition, it is possible to pull the distal part 2 out of the channel 13 again if a certain pull-out force is exceeded, because then the projections 20 slide with their lower sliding surface 21 along the ring step 14 and radially follow with elastic deformation of the tongues 19 shifted inside.

This pulling out of the holding shaft 4 from the channel 13 can be prevented by inserting a clamping element 23 into the channel 13 from the proximal end thereof, which has a circular cylindrical block section 24 , a proximally immediately adjacent one, from the blocking section 24 in the proximal In the direction of widening conical clamping section 25 , an external thread section 26 adjoining in the proximal direction and a contact section 27 adjoining in the proximal direction in the form of an external polygon. This clamping element can be guided from the proximal side into the channel 13 , the blocking section 24 entering the interior of the sleeve-shaped end region of the holding shaft 4 . The outer diameter of the Blockierab section 24 is selected so that it speaks in the wesentli Chen the inner diameter of the undeformed sleeve, so that the insertion of the Blockierab section 24 can be prevented that the gene 19 moves elastically radially inward.

The dimensions of the clamping element 23 are selected so that when the external thread section 26 is partially screwed into the internal thread 16 of the channel 13, the blocking section 24 is arranged loosely inside the holding shaft 4 without the tongues 19 elastically bending outwards. In this position, in which the clamping element 23 is not fully screwed into the channel 13 , the tongues 19 are not pressed against the inner wall of the channel, so that the distal part 2 and the proximal part 6 are still freely rotatable relative to one another are. However, it is already prevented that the tongues 19 can be elastically bent radially inward, so it is no longer possible to pull the holding shaft 4 out of the channel 13 .

When the clamping element 23 is screwed further into the internal thread 16 , the conical clamping section 25 enters the blind hole 17 and thereby urges the elastic tongues 19 radially outwards. These are thereby firmly clamped against the inner wall of the channel 13 and thereby secure the holding shaft 4 not only against pulling out but also against twisting relative to the proximal part 6 . The two parts 2 and 6 of the bone rasp 1 are then rigidly connected to one another.

It is therefore possible for the surgeon, after plugging together the distal part 2 and the proximal part 3 and after not yet fully screwing in the clamping element 23, to select the desired relative angular position of the distal part 2 relative to the proximal part 6 and this Then fix the angular position permanently by completely screwing in the clamping element 23 .

Conversely, the two parts of the bone rasp 1 can be easily separated from one another by completely unscrewing the clamping element 23 , it is then possible to pull the holding shaft 4 out of the channel 13 by a strong pull.

The described parts of the bone rasp 1 are made of a body-compatible metal, and the bone rasp 1 actuated via the handle (not shown in the drawing ) can be used to prepare the receiving space for an endoprosthesis shaft. It is also possible to use the rasp bone 1 as a trial stem due to its special shape.

The bone rasp of FIG. 4 has the same structure as that of Fig. 2, it differs from this le diglich characterized in that the distal part in the region of the annular step 5 carries a scale 30 while the proximal portion immediately adjacent to this scale 30 a Marking 31 has. As a result, the relative angular position of the distal part 2 can be read relative to the proximal part 6 . The distal part 2 can also be bent differently than shown in the drawing, so that when the distal part is bent and there is a different angular position, a bone rasp with different geometry results, which is optimally twisted by the di stal part 2 relative to the proximal part 6 the anatomical conditions of the bone to be processed can be adapted.

The embodiment of FIG. 5, which is constructed in wesentli chen the same as the embodiment of FIGS. 1 to 4 and therefore bear the same reference numerals in the same parts, has in the channel 13 two spaced ring steps 14 a and 14 b , namely a proximal ring step 14 a and a distal ring step 14 b. The outside diameters of these ring steps are the same.

If the support shaft 4 is pushed in the distal portion 2 completeness, dig into the channel 13, are the advantages cracks 20 of the support shaft 20 at the proximal annular step 14 on a, as has been discussed in the embodiment of Fig. 1 to 4.

If the holding shaft 4 is only partially inserted into the channel 13 , the projections 20 can be arranged at the level of the distal ring step 14 b. In order to achieve a defined insertion depth here, a spacer sleeve 32 is pushed onto the holding shaft 4 .

The clamping element 23 is formed correspondingly longer in the embodiment with spacer sleeve 32 , so that the conical clamping section 25 is arranged at the level of the distal ring step 14 b and there the projections 20 can clamp when screwing in the clamping element 23 .

It is thus possible to build up 6 rasps of different lengths with the same distal part 2 and the same proximal part. Without using a spacer sleeve 32 there is a short structure, when using a spacer sleeve 32 a longer structure. For this purpose, it is necessary to additionally push the spacer sleeve 32 over the holding shaft 4 and to use a longer clamping element 23 . Of course, it would also be possible to see a larger number of ring steps, then correspondingly graduated spacer sle and appropriately graduated clamping elements should be inserted so that the length of the bone rasp could then be varied in steps.

Claims (20)

1. Modular bone rasp or modular built shaft implant with a proximal part and with a distal part and with coupling means for releasably connecting the proximal part to the distal part, characterized in that the proximal part ( 6 ) one from proximal to distal Continuous channel ( 13 ) has that the distal part ( 2 ) has a from its distal end in the channel ( 13 ) insertable and in the fully inserted state inside the channel ( 13 ) ending holding shaft ( 4 ) on his free end ends in the form of a sleeve, the wall areas ( 19 ) of which can be expanded elastically, and that in the proximal end of the channel ( 13 ) engages in the sleeve-shaped end of the holding shaft ( 4 ) and the wall areas ( 19 ) of the sleeve expand and against the inside of the channel ( 13 ) clamping element ( 23 ) can be used. 2. rasp or shaft implant according to claim 1, characterized in that the clamping element ( 23 ) carries a conical, immersed in the sleeve clamping portion ( 25 ). 3. bone rasp or shaft implant according to claim 1 or 2, characterized in that the Klemmele element ( 23 ) in the proximal end of the channel ( 13 ) can be screwed. 4. bone rasp or shaft implant according to claim 2 and according to claim 3, characterized in that an external thread section ( 26 ) proximal to the clamping section ( 25 ) of the clamping element ( 23 ) closes. 5. rasp or shaft implant according to one of claims 3 or 4, characterized in that the clamping element ( 23 ) has at its proximal end a non-circular contact portion ( 27 ) for a turning tool. 6. rasp or shaft implant according to claim 5, characterized in that the contact portion ( 27 ) forms an outer or an inner polygon. 7. bone rasp or shaft implant according to one of the preceding claims, characterized in that the wall region ( 19 ) of the sleeve on its side from radially projecting projections ( 20 ) carries the completely inserted into the channel ( 13 ) NEM holding shaft ( 4 ) projections ( 14 ) on the inside of the channel ( 13 ) reach behind in such a way that the holding shaft ( 4 ) is secured against being pulled out of the channel ( 13 ), and that the projections ( 20 ) on the wall region ( 19 ) of the sleeve are elastically radi al are displaceable inwards until they can slide past the projections ( 14 ) on the inside of the channel ( 13 ) when the holding shaft ( 4 ) is pulled out of the channel ( 13 ). 8. bone rasp or shaft implant according to claim 7, characterized in that the projections ( 20 ) bearing wall region ( 19 ) of the sleeve is elastically bendable radially inwards. 9. rasp or shaft implant according to one of the preceding claims, characterized in that the wall region of the sleeve is divided by axially parallel incisions ( 18 ) in elastically bendable tongues ( 19 ). 10. bone rasp or shaft implant according to claim 9, characterized in that the elastic tongues ( 19 ) at their free end radially projecting projections ( 20 ). 11. Bone rasp or shaft implant according to one of claims 7 to 9, characterized in that the projection on the inside of the channel ( 13 ) is formed by a step-like extension ( 14 ) of the channel ( 13 ) in the proximal direction. 12. bone rasp or shaft implant according to claim 11, characterized in that the step-shaped extension ( 14 ) is chamfered. 13. Bone rasp or shaft implant according to one of claims 7 to 12, characterized in that the projections ( 20 ) on the wall region ( 19 ) of the sleeve have a bevelled sliding surface ( 21 ). 14. Bone rasp or shaft implant according to one of claims 7 to 13, characterized in that the inside of the channel ( 13 ) in its longitudinal direction at a distance from each other a plurality of projections ( 14 a, 14 b) for the projections ( 20 ) of the Halteschaf tes ( 4 ) carries and that between the proximal part ( 6 ) and the distal part ( 2 ) a spacer element ( 32 ) is arranged, which limits the insertion depth of the holding shaft ( 4 ) in the channel ( 13 ) so that the projections ( 20 ) on the holding shaft ( 4 ) engage behind one of the distal projections ( 14 b) on the inside of the channel ( 13 ). 15. Bone rasp or shaft implant according to claim 14, characterized in that the spacer element ( 32 ) is a spacer sleeve pushed onto the holding shaft ( 4 ). 16. bone rasp or shaft implant according to claim 14 or 15, characterized in that accordingly the position of the projections ( 14 a, 14 b) in the channel ( 13 ) and according to the length of the distant elements ( 32 ) different lengths of clamping elements ( 23 ) are provided are. 17. bone rasp or shaft implant according to one of claims 7 to 16, characterized in that the clamping element ( 23 ) in the sleeve of the Hal teschaftes ( 4 ) immersed, an elastic Ver displacement of the projections ( 20 ) of the holding shaft ( 4 ) inwards preventing blocking section ( 24 ), which, however, does not move the wall regions ( 19 ) of the sleeve in a clamping manner against the inside of the channel ( 13 ). 18. rasp or shaft implant according to claim 17, characterized in that the blocking section ( 24 ) immediately distal to the Klemmab section ( 25 ) of the clamping element ( 23 ) connects. 19. Bone rasp or shaft implant according to claim 18, characterized in that the blocking section ( 24 ) is formed by a circular cylindrical pin. 20. Bone rasp or shaft implant according to one of the preceding claims, characterized in that the proximal part ( 6 ) and the distal part ( 2 ) carry display elements ( 30 , 31 ) on which the angular position around the through the longitudinal axis of the channel ( 13 ) defined axis of rotation of the distal part ( 2 ) relative to the proximal part ( 6 ) can be read.