GB2052268A

GB2052268A - A device for guiding surgical instruments during realignment osteotomy on the human hip bone

Info

Publication number: GB2052268A
Application number: GB8016459A
Authority: GB
Original assignee: HUG GERHARD GmbH
Current assignee: HUG GERHARD GmbH
Priority date: 1979-05-17
Filing date: 1980-05-19
Publication date: 1981-01-28
Also published as: DE2919935A1; DE7914280U1; FR2456506A1; DE2919935C2

Abstract

A device for guiding surgical instruments during realignment osteotomy on the human hip bone comprises a fixing element (7) fixable against the femur (6) and a guide device (8) including a rotatable apertured guide member (21) for guiding the tools (e.g. drill (34)) required to produce the opening for the blade of an osteotomy plate, the guide device (8) being pivotably mounted on the fixing element (7) and placeable against the area of bone to be operated on. <IMAGE>

Description

SPECIFICATION A device for guiding surgical instruments during realignment osteotomy on the human hip bone The invention relates to a device for guiding surgical instruments, for example, during intertrochanter realignment osteotomy on the human-hip bone, i.e.

for the purpose of preparing the area to receive an osteotomy plate, which osteotomy plate comprises a fixing plate and a blade at right angles thereto and capable of insertion into the one - on or in the bone of the neck of the femur and head of femur.

Realignment osteotomy is one of the most important and most frequently implemented operations on the human hip joint. This realignment osteotomy is mainly used to treat congenital dislocation, in which treatment severe stress on the joint in comparison with the normal loading of the joint is eliminated by correcting the ration between the axes. Thus arthrosis may be prevented from occur rihg and existing arthroses or deformation of the head of the femur or diseases, in which improved joint angles or angles more in keeping with the acetabulum are achieved in the main load bearing area of the hip joint by carrying out an operation realigning the position between the shaft of the femur and the heat of the femur.

The so-called intertrochanter realignment osteotomy has proved to be successful worldwide as the best operating technique, in which the femur is cut just below the neck between the larger and the smaller undulation (greater and lessertrochanter), an appropriate wedge of bone is removed and the area of osteotomy is subsequently stabilized with an osteosynthetic plate. Today the means of providing osteosynthesis is usually the 90 degree osteotomy plate, the plate element being fixed by means of suitable screws to the shaft of the femur and the blade, angled perpendicular to the shaft is inserted into the bone of the neck of the femur and head of the femur.Since the blade is at right angles with the plate, the point where osteotomy takes place may be compressed by means of appropriate tensioning devices with screws before fixing the plate to the shaft and thus the osteosynthesis can be very stable.

In the case of intertrochanter realignment osteotomy, changes in the position of the head of femur are carried out in all three planes separatly or in combination: Changes in the angle of the neck of the femur in the frontal plane are designated as varus angulation in the case of a reduction in the angle and in the case of an increase in the angle are designated as valgus angulation. Tilting of the head of the femur in the sagittal plane forwardly is designated flexion and rearward tilting in the sagittal plane is designated as extention. The pivot position of the bone may be changed by means of inward or outward rotation as a a third correction.Realignment osteotomy requires very precise preoperative planning in accordance with X-ray pictures and drawings if corrections in position are to be carried out in several planes (changes in one plane always have an effect on the effective angle of other planes e.g. each flexion or extension produces an additional change in varus angulation at the same time).

The present-day operating techniques frequently render precise planning useless however, since they leave much to be desired when it comes to precision and are above all dependent on the optical judgment of the surgion. The operating techniques usual today are as follows: Small triangles used for measurement are arranged on the bones in order to determine and mark the different angles and directions and thin KIRSCHNER drilling wires are drilled into the bones.

Then, for example, in the case of combined flexion and varus angulation osteotomy, five drilling wires are necessary: the first drilling wire is designated to.

mark the direction of the neck of the femur, the second to mark the subsequent positioning of the plate in the frontal plane or to mark the varus angle, the third is to mark the flexion angle in the sagittal plane and the fourth and fifth drilling wires are placed one each over and under the subsequent area for osteotomy in order to mark the rotary position.

The decisive step in the operation is then preparing the seating for the blade of the osteotomy plate in the neck of the femur. The seating for the blade alone decides the subsequent positioning of the head of the femur since, in each case, the shaft of the femur is fixed at right angles to the plate blade by the rectangular shape of the osteotomy plate. The seating of the blade in the neck of the femur is prepared by drilling three adjacent bores and subsequently the so-called plate seat instrument is inserted, this instrument having the same profile as the plate blade.During preliminary drilling and insertion of the plate seat instrument, the surgeon must endeavour as far as possible to stay exactly parallel to all three drilling wires marking the different planes and directions - the direction of the neck of the femur. the direction of the varus or valgus angle, and the direction of the flexion or extension angle - and this is exceptionally difficult and often very inexact.

Subsequently the bone is separated by removing an appropriate wedge of bone with an osciallating saw on the one hand in parallel with the plate seat instrument and on the other hand perpendicular to the shaft of the upper femur.

The decisive factor for stability of the subsequent osteo synthesis is that osteotomy should take place at the correct spacing (15 - 20 mm) beneath the blade seat. Too small a spacing may cause the plate to break away from the bone and too large a spacing means that the osteotomy is no longer intertrochanter and thus the plate can no longer be fully inserted on the one hand and on the other hand the biomechanics of the body will be affected disadvantageously because of the various muscle attachments located in this region of the bone, After osteotomy, the plate seat instrument is removed again and the blade of the osteotomy plate is inserted into the prepared seating.Compression of the osteotomy point follows using the conventional plate tensioning devices and then the plate is fixed to the shaft of the upper femur by means of screws, the exact position of rotation of the shaft of the upper femur has to be taken into account and/or any desired change in that rotary position again by way of drilled wire pins which were inserted earlier and the triangle which was used for measurement and has been retained.

The description of the operating technique should make it clear that keeping in continuous alignment by using of numerous drilled wires is a difficult and inexact process for the surgeon. Fairly large inaccuracies arise as has been found by experience in addition to the fact that the thin drilling wire pins often bend during the course of the operation since they are in the way quite considerably for the remaining parts of the operation such as preliminary drilling of the plate seat with the drill or osteotomy with the bone saw. The essential disadvantage of these wires is moreover that they often damage the surgeon's gloves and thus make the condition less sterile.

The invention therefore seeks to create a device for guiding instruments during realignment osteotomy by means of which the accuracy of the operating techniques can be increased considerably and at the same time the operation can be simplified and shortened in terms of time and wherein, in particularthe use of drilling wire pins can be avoided.

According to the invention there is provided a device for guiding surgical instruments during realignment osteotomy carried out on the human hip, bone, i.e. for preparing the seating of an osteotomy plate which plate comprises a fixing plate and a blade arranged approximately at right angles thereto and capable of being inserted into the bone on or in the bone of the neck of the femur and the head of femur wherein the device comprises a fixing element which is fixable and placeable against the femur and a guide device for the tools required to produce the opening for the blade, the guide device being settable with respect to the fixing element about two axes which are at right angles to each other, and being placeable against the area which is to be operated on.

Such a device may therefore be used to set the exact position of the blade of the osteotomy plate afterfixing the appropriate angle and before the operation actually begins. The operation may be carried out more quickly therefore, the guide device making the disturbing and expensive drilling wire pins superfluous and providing a more precise arrangement of the bearing for the osteotomy plate.

It is particularly advisable if the fixing element comprises and abutment arm, which may be fixed to the shaft of the upper femur and if the guide device, which is fixable and may be pivoted about an axis orientate perpendicularly to its length and approximately tangentially to the cross-section of the bone is provided with at least one guide recess and an abutment surface for abutment against that area of the bone which accommodates the blade of the osteotomy plate, the guide recess corresponding to the cross-section of the blade being fixable and pivotable about an axis running approximately per pendicularto the abutment surface and at right angles to the pivot axis between the guide device and the abutment arm.The guide opening for the instruments may then be located exactly over the point at which the plate seating is to be arranged in the bone, in the form of a corresponding opening, after the device has been set and fixed in the correct position on the femur. The two possibilities of adjustment thus permit very precise setting enabling exact "aiming" of the appropriate instruments.

Thus the guide recess may run in the direction of its axis of rotation and the axis of rotation may, for preference, be arranged at the centre of the guide recess. This permits corresponding tilting of the recess and thus also of the subsequent blade seat, depending on the direction of orientation of the wedge of bone which is to be removed, for example in flexion osteotomy. The abutment arm may have an angled portion or a similar deformation forming the transition from its abutment region to the bearing point of the pivot axis for the guide device in accordance with the curve between the shaft of the femur and the region of the neck of the femur on the side remote from the shaft.Thus it is particularly advisable if at least two differently angled abutment arms may be connected to the guide device in exchangeable manner for guiding the blade of the plate seating in different directions - e.i. either say in the dire#ction of the neck of the femur (varus angulation osteotomy) or in the same plane but transverse to the neck of the femur (valgus angulation osteotomy). In practise there is a set of appliances or devices for matching different anatomical requirements.

A drill bush may be provided which fits into the guide recess of the guide device and has adjacent openings as guides for a drill designed to drill the opening for the plate seat instrument. The area may be preliminarily drilled correspondingly rapidly and precisely, with the aid of the device in with this additional component of the device assembly. where the plate seat instrument is to be inserted in order to prepare the seating for the blade. This process may be carried out correspondingly accurately and rapidly.

A further refinement for improving the operating techniques may lie in providing the guide device with a second guide opening between the rotary part and its pivot bearing as a marking hole for preliminary marking of the upper edge of the wedge bone to be removed. Furthermore, it is advantageous for the purpose of marking a possible rotation movement, if the abutment arm has at least one guide opening as a marking hole for a rotation movement between the shaft of the femur and the neck of the femur. These marking holes may serve for the guiding of drills by means of which the appropriate marking may be made on the bone. If the two parts of the bone are then separated they may be joined together in the angular position desired because of the correspond ing markings.

Overall the device in accordance with the invention makes it possible to set the angle of the frontal plane and of the sagittal plane envisaged during realignment osteotomy with a substantial simplification of the entire operating technique, a high degree of accuracy is achieved at the same time as a shortening of the duration of the operation.

The invention will now be described in greater detail, by way of example, with reference to the drawings in which: Figure 1 shows a device in accordance with the invention after it has been arranged on a bone of the hip joint for valgus angulation osteotomy, in which 25 degrees of valgus angulation is set and a drill bush and a drill for preliminary drilling of the plate seating have been attached; Figure 2 is a view corresponding to Figure 1 for varus angulation osteotomy at a varus angle of 25 degrees in which a plate seat instrument has already been fixed; Figure 3 is a rear view of the device which is set and provided, in this case, at the same time, for flexion osteotomy;; Figure 4 is a view corresponding to Figure 1 in which the upper side of the wedge of bone to be removed on the one hand and on the other hand the rotary position of the device as compared to the shaft of the bone is marked by additional marking openings with the aid of drills; Figure 5 shows how a chisel-like plate-seat instrument is arranged, its cross-section corresponding approximately to that of the blade of the osteotomy plate, after the opening has been preliminarily drilled in accordance with Figure 1; Figure 6 shows the device in accordance with the invention being removed by means of the plate seat instrument; Figure 7 shows the actual osteotomy being carried out parallel to the plate seat instrument and perpendicular to the shaft of the femur in accordance with preliminary marking;; Figure 8 is the rear view of the corrected bone after the osteotomy plate has been attached; and Figure 9 is a side view corresponding to Figure 8.

A device designated 1 overall serves to guide surgical instruments when preparing the seating of an osteotomy plate 2 (Figures 8 and 9), the osteotomy plate comprising a fixing plate 3 and a blade 5 which can be inserted into the bone in the region of the neck 4 of the femur and serves to retain and compress, the osteotomy, both parts of the bone which have been separated. Above all the opening for this blade 5 must be arranged on the bone as precisely as possible and as rapidly as possible.

The device in accordance with the invention has an abutment arm 7 which may be fixed to the shaft 6 of the femur as its fixing element and a guide device 8 which is to be described in greater detail, the said guide device permitting different setting movements designed to match the different angles through the bone. The guide device is therefore pivotable about an axis 9 oriented perpendicular to the expanse of the abutment arm 7 and approximately tangentially of the cross-section of the bone and may be fixed in any desired pivoted position. It has a guide recess 10 and an abutment surface 11 which is to be placed against that area 12 of the bone which later accommodates the blade 5 of the osteotomy plate 2.The guide recess 10, which has been mentioned, may be seen particularly easily in the plan view according to Figure 3 and at the same time it is shown that this guide recess 10, which corresponds approximately to the cross-section of the blade is pivotable and fixable about an axis 13 which runs approximately perpendicular to the abutment surface 11 and at right angles to the pivot axis 9. Besides the initial setting possibility of appropriately placing the abut ment arm 7, there are also two setting possibilities by means of the guide device by pivoting it with respect to the abutment arm 7 about the axis 9 and by means of the rotatability of the guide recess 10 about the axis 13. The recess 10 may be oriented suitably accurately in the direction in which the bearing or the opening for the blade 5 is to be arranged in the bone.

In Figures 1 to 5, it may be seen that the guide recess 10 runs in the direction of its axis of rotation 13 and this axis of rotation 13 is arranged at the centre of the guide recess 10. In Figure 3, it is clear how the subsequent position of the cross-section of the blade may be preselected relative to the bone as a result of this rotatabilityofthe guide recess 10, and in this way a flexion or extension osteotomy may be carried out together with and at the same time as a valgus or varus angulation osteotomy because of the pivotability of the guide device 10. Figure 3 therefore shows flexion osteotomy.

In Figure 1, it may be seen that the abutment arm 7 has an angle portion 14 or a similar deformation forming the transition from the abutment region 7a to the bearing point 15 of the pivot axis 9 for the guide device 10 in accordance with the curve 16 between the shaft 6 of the upper femur and the region 17 of the neck of the femur on the side remote therefrom. Thus it is possible in this way to take account of anatomical considerations so that, the abutment arm 7 may be fixed to the shaft 6 of the upper femur as a fixing element while the guide device may abut against the region 17 of the bone where the seating is to be formed for the osteotomy plate 2.

Comparison between Figures 1 and 2 shows that two differently angled abutment arms 7 may be connected to the guide device 8 for guiding the blade Sin different directions - i.e. either in accordance with Figure 2 in the direction of the neck of the femur or in accordance with Figure 1 in the same plane but transverse to the neck of the femur. Depending on the correction which is to be carried out - either in accordance with Figure 1 i.e. valgus angulation osteotomy or in accordance with Figure 2 varus angulation osteotomy - one or other abutment arm 7 is preselected for the device 1 and the appropriate setting of the different angular positions is im plemented accordingly. Therefore, in the device in accordance with the invention there is a series of devices in practice.

It is possible to see by way of Figures 1 to 6 that, in the region of the pivot axis 9 between abutment 7 and guide device 8, there is provided a preferably two-sided angle scale 19 on which it is possible to preselect the angle between the abutment arm and the drill in the manner shown and thus also to preselect the angle between the femur and the plate seating before carrying out the osteotomy, while the scale rises at both sides from a centre value in order to be able to set the valgus angulation and varus angulation osteotomy in the same manner. In Figure 1, for example, a valgus angulation osteotomy is set having an angle of 25 degrees. Figure 2 shows setting of a varus angulation osteotomy also at 25 degrees.

In accordance with Figure 3, the abutment arm 7 is bifurcated in the region of pivot axis 9 and engages on both sides over an attachment 18 of the guide device 8while the angle scale 19 is provided on the guide extension 18, preferably on both sides so that the device may be used both for the left femur and for the right femur. In the region of the pivot axis 9, again preferably on both sides, there is a pointer 20 moulded on to the abutment arm 7, preferably integrally therewith and projecting into the region of the respective angle scale 19. This may be seen particularly clearly for example in Figures 1 and 2 where the pointer 20, firmly connected to the abutment arm 7 in each case, indicates the appropriate angle on the scale which may be pivoted relative thereto.

In the embodiment shown the pivot axis 9 between the abutment arm 7 and the guide device 8 is formed as a screw, the counter thread being provided in one of the openings of the bifurcated member of the abutment arm 7 so that a nut is superfluous. Thus this screw, serving as a pivot axis 9, is at the same time provides a clamping screw for fixing a set angle between the abutment arm 7 and the gide device 8. A stepless setting is therefore possible.

The guide member 21 on the guide device 8, which is rotatable and has the guide recess 10, is arranged in a clamping ring 23 which may be spread out or drawn together, preferably by means of a further clamping screw 22, and which is slit at least on one side and has a scale 24 for marking the flexion or extension osteotomy on its outside in this embodiment. In Figure 4, for example, the setting of 15 degrees of flexion may be seen on the scale, which scale rises on both sides from a zero position.

In the embodiment shown the clamping screws have socket head openings 25 which are preferably the same so that both screws may be ectuated with the same tool. The clamping screw which at the same time serve as a pivot axis 9 has both a socket head opening 25 and an outer polygonal head 26 so that, if necessary, a spanner able to apply a sufficiently large force may be used.

In Figure lit may be seen that the abutment arm 7 may be fixed to the femur with a bracket or pincers, the jaws 27 of which are indicated, the abutment arm 7 projections 28 directed against the bone forming displacement preventing elements in order to prevent unintentional displacement during the subsequent work with the device.

In Figure 3 it may be seen that the guide recess 10 has a rectangular contour in accordance with the outer contour of the blade 5 of the osteotomy plate 2.

Furthermore, the guide recess 10 in the rotary part 21 has a broadened portion 29 on one side corresponding to a withdrawal projection 30 on a plate seat instrument 31 which is still to be described and which serves to prepare the opening for the blade 5 so that the device 1 may be removed from the femur after this plate seat instrument 31 has been inserted and before it has been removed, as shown in Figure 6. The plate seat instrument 31 serves to preliminary form the seating for the blade 5. The plate seat instrument is only inserted when appropriate initial bores have been made in the bone. Later, the plate seat instrument 31, inserted with the aid of the guide device 8 forms a parallel guide for a saw 32 as well, in order to carry out a first cut through the bone in accordance with Figure 7.

A drill bush 33, with adjacent openings as guides, foradrill34forpreliminarydrilling of the opening for the plate seat instrument, as has already been mentioned, is part of the device and fits into the guide recess 10 of the guide device 8. The drill bush 33 and its cooperating drill 34 may be seen in Figure 1. The drill bush fits into the narrow rectangle of the guide recess 10 and may have three closely adjacent and parallel bores 35 in which the outer spacing of the outer bores almost corresponds to the width of the plate seat instrument 31. The plate seat instrument 31 may be inserted just as if these three bores are arranged adjacent each other. Thus the bores may be arranged very precisely at the preselected angle relative to the femur because they are guided accurately by the drill bush 33 which in turn is exactly aligned by the guide device 8.After removing the drill bush, the plate seat instrument 31 may be inserted just as accurately into the base with the aid of the device 8. It can be seen that the drill bush 33, corresponding in its outer contours to the inner contours of the guide recess 10, has a handle 36 on its side remote from the bone in its operative position, the handle being provided on a stop plate 37. This plate 37 may at the same time prevent any slipping along the drill bush when the drill is being attached.

The guide device 8 has between the rotatable guide member 21 and the pivot bearing penetrated by the axis 9, a second guide opening in the form of a marking hole 38 for preliminary marking of the upper limit of the wedge 39 of bone which is to be removed and this is shown in Figures 3 and 4. The marking according to Figure 4 may be carried out simply by a drill bit 40 of drill 34, for example. Thus it is possible, in a simple and effective manner, to prevent osteotomy from taking place at an incorrect spacing beneath the blade seat.

In the same Figures, it can be seen that the abutment arm 7 has a guide opening 41 as marking hole to enable a rotary movement between the shaft of the femur and the neck of the femur being able to be checked. If the original position of the device relative to the blade seat is marked, using the guide opening 41, by a drill bit 40, then a correspondingly accurate rotation between the two parts of the bone may be carried out after the cuts have been made.

Thus it may be advantageous if the width of the abutment arm 7 on both sides of the marking hole 41 is located at its centre corresponds, in each case, to a proportion of 25 degrees of the circumference of the bone. Corrections in rotation of this type are are quently in this range. Thus the abutment arm 7 is longer than the fixing plate 3 of the osteotomy plate and the marking hole 41 in the abutment arm 7 is located in that region in which the abutment arm 7 is longer than this fixing plate 3, so that, even after applying this plate, the marking is still visible. The width of the abutment arm and the width of the fixing plate may be the same. In any case it is advantageous if the centre of the fixing plate 3 of the osteotomy plate has a spacing corresponding to a 25 degree rotation from its edges.After applying the plate and after fixing the blade, the appropriate rotation relative to the marking may be estimated or measured rather more accurately, if necessary, and accordingly the fixing plate of the osteotomy plate may be screwed to the bone in known manner as shown in Figures 8 and 9.

Overall, the device 1 as above described permits intertrochanter realignment osteotomy in which the duration of the operation is reduced and the operating technique is simplified.

It is in fact possible to set the intended blade angle of the osteotomy plate in the frontal plane initially on the device and at the same time to exactly set the angle of rotation in the sagittal plane by means of the angle graduations present on the device. The device may be fixed to the shaft of the femur with the aid of a conventional Lambotte pincer for example after which the guide device 8 guides the appropriate tools exactly i.e. the drill in the first instance and then the plate seat instrument 31. In addition the correct height of the osteotomy and the position of rotation of the femur shaft are marked in the manner already mentioned by means of the device. The device therefore replaces the conventional measure- menttriangle and numerous drill wires which were previously used to mark the various planes and directions and had disadvantages with regard to inaccuracy and the danger of injury as well as extending the duration of the operation. At the same time the greater accuracy which has already been mentioned can be achieved while at the same time greatly simplifying and thus shortening the entire operation.

Claims

1. A device for guiding surgical instruments during realignment osteotomy carried out in the human hip bone i.e. for preparing the seating of an osteotomy plate which plate comprises a fixing plate and a blade arranged approximately at right angles thereto and capable of being inserted into the bone on or in the bone of the neck of the femur and the head of femur wherein the device comprises a fixing elementwhich is fixable and placeable against the femur and a guide device for the tools required to produce the opening for the blade, the guide device being settable with respect to the fixing element about two axes which are at right angles to each other, and being placeable against the area which is to be operated on.

2. A device according to Claim 1, where the fixing element comprises an abutment arm fixable on the femur shaft and the guide device, which is fixable and may be pivoted about an axis oriented perpendicular to its extension and approximately tangentially of the cross-section through the bone, is provided with at least one guide recess and an abutment surface for placing against that part of the bone which is to accommodate the blade of the osteotomy plate while the guide recess, approximately corresponding to the cross-section of the blade, is rotatable and fixable about an axis approximately perpendicular to the abutment surface and at right angles to the pivot axis between the guide device and the abutment arm

3. A device according to Claim 2, wherein the guide recess runs in the direction of its axis of rotation.

4. A device according to claim 3 wherein the axis of rotation is arranged at the centre of the guide recess.

5. A device according to any one of Claims 2 to 4, wherein the abutment arm has an angled portion or a similar deformation forming the transition from its abutment area to the bearing point of the pivot axis for the guide device in accordance with the curve between the shaft of the femur and the area of the neck of the femur on the side remote from the shaft of the femur.

6. A device according to any one or more of Claims 2 to 5, wherein at least two differently angled abutment arms are changeables connectable to the guide device for guiding the blade in different directions.

7. A device according to any one of Claims 2 to 6, wherein an angle scale is provided within range of the pivot axis between the abutment arm and the guide device.

8. A device according to Claim 7, wherein the angle scale is two sided.

9. A device according to Claims 7 or 8, wherein the- abutment arm is bifurcated in the region of the pivot axis and engages across an extension of the guide device on both sides thereof.

10. A device according to Claim 9 wherein the angle scale is provided on said guide extension.

11. A device according to any one of Claims 7 to 10, wherein in each case an indicator is moulded on to each side of the abutment arm in the region of the pivot axis and projects into the region of each angle scale.

12. A device according to Claim 11, wherein the indicators are integral with the abutment arm.

13. A device according to Claim 9 or any claim appendent directly or indirectly thereto wherein the pivot axis between the abutment arm and the guide device is formed as a screw, the counter thread of which is provided in one of the openings in the bifurcated member of the abutment arm.

14. A device according to Claim 13 wherein the screw serving as the pivot axis also acts as a clamping screw at the same time for fixing a set angle between the abutment arm and the guide device.

15. A device according to any one of Claims 2 to 14, wherein the guide recess is formed in a guide element rotatable in the guide device, the guide element being arranged in a clamping ring which is slit at least on one side and is spreadable apart and drawable together by means of a clamping screw or the like.

16. A device according to Claim 15, wherein the clamping ring is provided with a scale or a similar marking.

17. A device according to any one of Claims 2 to 16, wherein the guide recess has.a rectangle contour corresponding to the outercountour of the blade of the osteotomy plate.

18. A device according to any one of Claims 2 to 17, wherein the guide recess in the rotary element has a broadened portion on one side corresponding to a withdrawal projection, on a plate seat instrument designed to prepare the opening for the blade, so that the device may be removed from the femur with the plate seat instrument inserted in the bone.

19. A device more particularly according to any one of Claims 2 to 18, wherein a drill bush is provided, fitting into the guide recess of the guide device, the drill bush having adjacent openings as guides for a drill designed to pre-drill the opening for a plate seat instrument.

20. A device according to Claim 19, wherein the drill bush has three closely adjacent and parallel bores in which the outer spacing of the outer bores almost correspond to the width of the plate seat instrument.

21. A device according to Claim 19 or 20 wherein the outer contour of the drill bush corresponds to the inner contour of the guide recess and a handle is provided on the side of the drill bush remote from the bone, in the functioning position.

22. A device according to Claim 21, wherein the handle is provided on a stop plate provided on the bush.

23. A device according to any one of Claims 2 to 22, wherein a plate seat instrument which has been inserted with the aid of the guide device also forms a parallel guide for a saw designed to carry out a first cut through the bone.

24. A device according to any one of Claims 2 to 23, wherein the guide device has a second guide opening as a marking hole for a preliminary marking of the upper edge of the wedge of bone which is to be removed.

25. A device according to Claim 24, wherein the marking hole is provided between the rotatable pivoting part of the guide device and the pivot axis between the guide device and the abutment arm.

26. A device according to any one of Claims 2 to 25, wherein the abutment arm has at least one guide opening as a marking hole for a rotary movement between the femur shaft and the femur neck.

27. A device according to any one of Claims 2 to 26, wherein the abutment arm, which is fixable by means of a bracket to the femur has pointed projections or similar locking elements preventing displacement of the abutment arm and directed against the surface of the bone.

28. A device according to Claim 26, wherein the abutment arm is longer than the fixing plate of the osteotomy plate and the guide opening is arranged in the abutment arm in that region of the abutment arm which would occupy the same position as the fixing plate of the osteotomy plate.

29. A device according to Claim 28, wherein the width of the abutment arm on both sides of the guide opening which is located at its centre corresponds in each case to a proportion of the circumference of the bone of 25 degrees.

30. A device according to Claim 28, wherein the width of the abutment arm corresponds to the width of the fixing plate and the centre of the fixing plate is spaced from its edges in each case by 25 degrees.

31. A device according to Claims 14 and 15, wherein the clamping screws have the same socket head openings.

32 A device according to Claim 31, wherein at least the clamping screw serving at the same time as a pivot axis between the abutment arm and the guide device has both a socket head opening and an outer polygonal head.

33. A device for guiding surgical instruments during realignment osteotomy substantially as described herein with reference to the drawings.