EP2515771A1

EP2515771A1 - Femoral cutting guide device for revision operations in knee endoprosthetics

Info

Publication number: EP2515771A1
Application number: EP10776314A
Authority: EP
Inventors: Beat Grunder; Christoph Fankhauser; Walter Supper
Original assignee: Mathys AG Bettlach
Current assignee: Synthes Bettlach GmbH
Priority date: 2009-12-23
Filing date: 2010-10-28
Publication date: 2012-10-31
Also published as: WO2011076308A1; AU2010335620B2; JP2013515517A; AU2010335620A1; US20120136359A1; DE102010013259A1

Abstract

The invention relates to a device for carrying out bone cuts on the distal femur in knee endoprosthetics, having a main body (11), which comprises an anterior cutting block (12), which is arranged on the main body (11) and determines an anterior cutting plane, and a posterior cutting block (13), which is arranged on the main body (11) and determines a posterior cutting plane (16). The distance between the anterior cutting plane (14) and the posterior cutting plane (16) can be altered.

Description

Femoral incision device for revision surgery in knee arthroplasty

The invention relates to a device for

Carrying out bone cuts on the distal femur bone in knee endoprosthetics, in particular for

Revision surgery.

A total used in the human body

Knee prosthesis has a lifespan of about 10 to 20 years. A variety of causes, especially abrasion of the tibial inlay, implant loosening and knee instability lead to failure of the primary total knee prosthesis and require replacement of the total knee prosthesis in a knee revision surgery. The

Removal of the primary total knee prosthesis is associated in part with massive bone loss and the

resulting boundary conditions for the use of a

Revision implant are very different. To cope with this variety of possible defects and occurrences within a revision surgery is

typically requires a wide variety of revision instruments. As with the implantation of a primary knee prosthesis, e.g. Instruments for

maintain different femoral sizes during surgery.

WO 06/042743 A2 describes a ligament-tensioning device and a cutting block in preparation for the

Implantation of a joint implant, which is not suitable for revision surgery. In this case, a presettable and readjustable Resektionshöhe for the medial and the lateral side is set separately from each other by the described ligament tensioning device and made a corresponding distal bone cut using a cutting jig. To carry out the anterior or posterior section and the anterior or

posterior oblique incision, a further cutting gauge is used, which is selected according to the size of the existing femur bone. Typically, five femoral implant sizes require five different femoral cut blocks. Thus, in each operation not only different instruments, but also different sizes of the instruments must be maintained. This makes the operating environment confusing and increases the cost of a larger storage.

It is therefore the object of the present invention to reduce the number of operations, in particular one

Revision surgery to reduce necessary tools and a simple and intuitive handling of these

Allow instruments.

The object is achieved by the device according to the invention according to claim 1. In the dependent claims contain advantageous developments of the invention

Device shown.

The device according to the invention for performing bone cuts on a distal femur bone in the knee endoprosthesis comprises a base body, on which an anterior cutting block is arranged, which defines an anterior cutting plane. On the main body, a posterior cutting block is further arranged, which defines a posterior cutting plane, wherein the distance between the anterior cutting plane and the posterior cutting plane is variable. Thus, advantageously, the distance between the anterior and the posterior

Cutting plane to the different femoral sizes, or femur implant sizes are adjusted. The

inventive device thus replaces several

Conventional femur cut blocks and combines them in one. This not only lowers the number of one

Operation held instruments, but reduced this significantly reduces the cost of the

Surgical instruments.

It is advantageous that a change in the distance between the anterior cutting plane and a base plane parallel thereto through the base element is associated with a change in the distance between the posterior cutting plane and the base plane. The change in the distance between the anterior section plane to the base plane and the change in the distance of the posterior section plane to the base plane have a fixed relationship to each other. Thus, after the alignment of the main body to the femur bone, the distances of the anterior cutting plane and the posterior cutting plane can be changed together in a single step. A separate adjustment of the anterior cutting plane or the posterior cutting plane is

necessary. The fixed relationship between the changes in the distances of the anterior and posterior planes of intersection are the anatomical ones

Size ratios and in particular adapted to the dimensions of the different Femurimplatatgrößen. This

Ratio can be adjusted suitably for dimensions of implants of different manufacturers in a further model of the device according to the invention.

Advantageously, the body preferably has a display indicating the adjustment of the distance between the anterior and posterior cutting planes corresponding to a size of a femoral implant. This allows the precise and fast adjustment of the cutting planes to the selected size of the femoral implant.

Advantageously, the anterior cutting block and the posterior cutting block are preferably through

Intermediate element connected, wherein the intermediate element has two threads with opposite direction of rotation and has different pitch. Through the thread in the intermediate element, a continuous change in distance can be made, so that a fine adjustment is possible. Due to the different pitches can be a constant over the entire range change range

Relationship between the displacement of the anterior cutting plane and the posterior cutting plane can be ensured. By using different pitch heights, the ratio of the change in distance between the anterior and posterior cutting planes can be changed.

It is further advantageous if the base body has a recess in which a sleeve is releasably fixed. The recess runs around one of zero

different angles to the perpendicular of an end face of the body in the medio-lateral direction inclined through the body through. Advantageously, a

rod-shaped element, which is introduced in the intra-medullary canal of the bone, held in the sleeve. This allows a fixation of the body on a characteristic axis of the bone, which later serves to attach the revision implant. By around a non-zero angle inclined recess cutting device according to the invention according to the natural valgus angle to

Femur bone axis to be aligned. This ensures that the cuts in the femur and subsequently the femoral implant are perpendicular to the mechanical axis of the femur

Femurs are aligned. This is important because the

Weight of the body along the mechanical axis acts on the knee joint.

It is also advantageous that the base body at an angle ß to the vertical of the end face of the

Body is rotated and fixed. This allows the alignment of the incision device according to the rotation of the femur, so that the support of the femur on the tibial inlay corresponding to the original physical Conditions takes place. This promotes the stability of the entire knee prosthesis.

Advantageously, a handle on the base element can be fastened, which protrudes in the medial and lateral direction over the end face of the base body. By these protruding handles reference points on the femur, in particular the Transepikondylen be targeted and brought by turning the handle to cover. Thus, the alignment of the primitive corresponding to the femur rotation is simple and intuitive.

Advantageously, a rod-shaped element is preferred in the intra-medullary canal of the bone

introduced and held. The rod-shaped element is held eccentrically, but parallel to the sleeve axis in the sleeve. This makes it possible to compensate for an offset between the intra-medullary canal and the physical axis of the socket at the femoral implant for stem extensions. The rod-shaped element marks the intra-medullary canal. In contrast, the middle of the sleeve marks the axis of the socket of the femoral implant for stem extensions. It is advantageous if the sleeve is rotatable about the axis of the rod-shaped element. this makes possible

on the one hand the femoral rotation of the

Adjusting the incision device or the femoral implant and on the other hand by circular translation of an anterio-posterior and medio-lateral

Fine alignment of the cutting guide device or the femoral implant to make.

Advantageously, a scale is preferably attached to the anterior cutting block, which indicates the medial-lateral width of a femoral implant. By turning the sleeve with offset, ie a sleeve with an eccentrically lying rod-shaped element, in the body can thus in a desired position of the anterior femoral cut a medial (eg 10 o'clock) or a lateral (eg 2 o'clock) position so that the marking of the scale coincides as well as possible with the lateral or medial edge of the femur bone. The marker is used according to the size of the femoral impulse selected in the anterior and posterior cutting plane.

Advantageously, the anterior cutting block has an anterior-pointing pin in which another cutting block, e.g. a distal cut block engages. This detachable distal incision block allows a so-called purging incision to be made at the distal end of the femur to match the subsequently performed anterior and posterior incisions or femoral implant.

It is also advantageous if the anterior incision block extends beyond the anterior cut plane

having attaching, facing in the proximal direction pedestal, with which a fixing element is connected. The fixation element is firmly connected to the femur bone. Thus, in addition to the rod-shaped element is a fixation of the cutting guide device,

especially in the distal-proximal direction, guaranteed.

The inventive device thus allows optimal alignment of the anterior / posterior cutting block to the femur, reduces the number of

Anterior / posterior cut gauges on just one element for all available femur implant sizes, allowing intuitive manipulation to align the device and providing support and reference for others

Cutting teachings, such as for the distal bone cut. Embodiments of the device according to the invention of bone sections are shown by way of example in the drawings and will be described with reference to the following

Description explained in more detail. Show it: an embodiment of a cutting guide device according to the invention in a perspective view; the embodiment of a cutting guide device according to the invention in section through the plane AA; a detailed view of an inventive

Embodiment of an intermediate element; the embodiment of a cutting guide device according to the invention in plan view; the embodiment of a cutting guide device according to the invention installed in a bone in the direction of the end face of the cutting guide device; the embodiment of a cutting guide device according to the invention installed in a bone in side view; Fig. 7 shows the embodiment of an inventive

Cutting guide device installed in a bone in plan view.

Corresponding parts are provided in all figures with the same reference numerals.

The pages and direction labels are in the

described below with respect to the intended installation position of the cutting guide device on the bone and the position of the bone in the body. The

Device according to the invention lies with her the

Front side opposite rear side at the distal end of the femur perpendicular to the mechanical axis

between the knee and hip joint on the femur bone. All further location designations are related to this basic position.

In Fig. 1, an embodiment of a

cutting device 10 according to the invention

perspective view looking towards the

Front side of the cutting guide device shown. The cutting guide device consists of a base body 11, on which an anterior cutting block 12 is aligned anteriorly and a posterior cutting block 13 are arranged oriented posteriorly. The base body 11 has a first recess 21, the inner surface 31 of which passes through the base body 11 at an angle not equal to zero, inclined to the perpendicular to the end face in the medial-lateral direction. Due to this inclined first recess 21, there are different cutting guide devices for the left and right knee, in which each of the first recess 21 is directed laterally. The orientation of the

Cut guide device 10 otherwise remains the same.

In the first recess 21, a sleeve 60, which is shown in Fig. 5.6 and 7, are inserted. By a retaining pin 29 which is screwed into the first recess 21, the sleeve 60 is fixed in position. The main body 11 also has holes 30 on the front side, in which additional components of the cutting guide device 10 can be fixed. With the main body 11, a posterior cutting block 13 is connected. A third recess 27 in the posterior cutting block 13 serves to receive a posterior

Cutting guide, as shown in Fig. 6. On the side opposite the posterior cutting block, there is an anterior cutting block 12 on the main body 11

appropriate. On the anterior-cutting block 12 side, which is anterior-looking, there is a scale indicating the medial-lateral size of the femoral implant. A corresponding scale is found on both Approximately in the center of the anterior cutting block 12, a socket 22 is formed which extends in the anterior direction and in the proximal direction

Overhangs direction over the anterior incision block. The base 22 serves as a support and fastening element for further cutting guide elements and for attaching a fixing element, such as in FIG. 7

is shown. A second recess 24 penetrates the base 22 and allows the introduction of a

Connecting element 83, see Fig. 6. About the base 22 protrudes a pin 23, which is directed in the anterior direction out. On the pin 23 are more

Cutting guide elements, such as the

Cutting guide element 81 in Fig. 6, pushed and fixed.

The upper side 32 of the anterior cutting block defines the anterior cutting plane 14. Likewise, the underside 33 of the posterior cutting block 13 defines the

Cutting plane 16. To perform a bone incision, a saw blade is placed on this cutting plane 14, 16 and guided along the cutting plane 14, 16. In order to be able to adapt the inventive cutting guide device 10 to different femoral sizes, the anterior cutting plane 14 and the posterior cutting plane 16 are displaceable.

In the embodiment shown, the position of the two planes 14 and 16 is displaced relative to the parallel base plane 15, which leads through the center of the first recess 21, by turning an adjusting tool, which is inserted into the recess 26. The distance 19 between the original anterior cutting plane and the newly adjusted anterior cutting plane 14 ¹ and the

Distance change 20 between the original

Posterior cutting plane 16 and the newly adjusted posterior cutting plane 16 'have a fixed relationship to each other. A typical relationship between anteriorer Distance change to the posterior distance change is 2: 5. By an indication on the front side 9 of the

Main body 11, which displays the femur implant sizes, and a corresponding adjustment mark 17, the anterior cutting plane or the posterior cutting plane can be adjusted to the distances corresponding to the size of the femur implant. Thus, no further cutting guide elements for the different femoral implant sizes are necessary. For example, five

Different femoral implant sizes now have four surgical instruments less available.

Fig. 2 shows a section through the plane of the embodiment shown in Fig. 1, which extends through the points A-A in the arrow direction. In the base body 11 is the retaining pin 29, which is accessible from the side surface of the base body 11 with an adjustment 40 and extends to the first recess 21 out. On the holding pin 29 opposite side of the

Base body 11 passes through a posterior

Guide elements 43 and an anterior guide member 44, the base body 11. These guide elements serve to stabilize the anterior or posterior cutting block 12, 13. The posterior guide member 43 has at its anterior end to an end stop 45 with a ring mark. This is visible on the front side 9 of the main body 11 and forms the adjustment mark 17 for the display 18 of the femur implant size. The anterior cutting block 12 and the posterior cutting block 13 are formed by an intermediate element 41

coupled. The intermediate element is rotatably mounted in the base body 11, but fixed in the axial direction. The section marked B is shown in FIG. 3

shown enlarged. The intermediate element 41 is inserted in a recess 57 of the main body 11 and is enclosed by a spring ring 54. The spring ring 54 has circumferentially a recess 56 into which a Retaining pin 55 engages. The retaining pin 55 is thereby pushed into a recess 70, which penetrates the base body 11 in the distal proximal direction, and into the recess 56 in the intermediate element 41. As a result, the intermediate element 41 is fixed in the axial or anterior-posterior direction.

A head portion 58 of the intermediate member 41 is circumferentially provided with a first thread 52. This engages in a thread with the anterior cutting block 12 in

Connection stands. These threads can either be cut into the anterior cutting block 12 or by a threaded sleeve 51, which is positively or positively inserted into a bore in the anterior cutting block 12, engage. The foot region 59 of the intermediate element 41 has a recess which has a second thread 53. A threaded pin 42 of the posterior cutting block engages the second thread 53. The first thread 52 and the second thread 53 have opposite

Turning directions on, i. are as legal or

Left-hand thread executed. Likewise, the pitch of the first thread 52 and the second thread 53

so that propulsion on the anterior side to propel on the posterior side of the

desired ratio shows.

Fig. 4 shows the embodiment of a

Cutting guide device 10, as shown in FIGS. 1 and 2

shown, in plan view. The display of the medial-lateral femur implant size 25, 25 'is clearly recognizable. The incision guide device 10 is brought into conformity with the lateral or medial edge of the femur bone on the basis of this display. This will check and ensure that the femoral implant is placed in the medial-lateral direction to match the femoral size of the femur. Likewise, the recess 26 for insertion of an adjusting tool 26 can be seen. The intermediate element 41 is easily accessible through this recess 26 and easily adjustable. In this illustration, the slope is the first

Recess 21 in the medial-lateral direction relative to the vertical 28 to the end face 9 illustrates. The

Inner surface 31 of the first recess 21 is shown extended by the dashed line. This is relative to the vertical 28 of the end face 9 to the

Angle α inclined. The angle α corresponds to the

Valgus angle under which the femur is tilted with respect to the physical axis 115. Thus, when fixing the incision guiding device 10 to the intramedullary canal 114, it can be ensured that the

Bone sections, in particular the distal bone section, perpendicular to the physical axis 115 is located. The location of said axes is shown in Fig. 7.

Fig. 5 shows the embodiment of a

Cutting guide device 10, installed on the distal femur in the direction of the end face 9 of the

Cutting guide device 10. A handle 67 is mounted on the base body 11 and protrudes in medio-lateral direction beyond the base body 11. By turning the handle 67 and aligning with prominent bone shapes of the distal femur, the incision guide device 10 is aligned according to the femoral rotation. to

Attachment of the handle 67 on the base body 11, the pins 68 in the handle 67 in the holes 30 on

Base 11, see Fig.l, plugged. A clockwise rotation about the angle ß, which is the femoral

Rotation corresponds to the center 61 of the sleeve 60, starting from the illustrated starting position of the

Handle 67, is shown in Fig. 5.

To compensate for a displacement of the physical axis attachment point 115 from the puncture point of the intra-medullary canal to the distal end of the femur, the

rod-shaped element 85 guided by an eccentrically introduced into the sleeve 60 recess. The distance between the center of the sleeve 61 and the center 64 of the The rod-shaped element 85 corresponds to the offset of the physical axis 115 to the intra-medullary canal 114. To fine-tune the position of the femoral implant in anterior-posterior or medial-lateral orientation, the sleeve is rotatably mounted around the rod-shaped element 85. Markings 63 on the sleeve head 62 and markings 65 on the handle 67 are circumferentially distributed around the sleeve 60 and facilitate the reproduction of the anteroposterior or medial-lateral position during subsequent installation of the femoral implant. In Fig. 5, a rotation 66 of the sleeve 60 about the center 64 of the rod-shaped element is shown. This rotation 66 causes a displacement of the center 61 of the sleeve 60 to position 61 'and thus a displacement of the cutting guide device 10 in the direction indicated and by the distance shown.

After adjusting the femur size, the femoral rotation and the offset between the physical axis 115 and intra-medullary canal 114 at the distal end of the femur, the incision guide device 10 via a

Fixing device 100, which is mounted on the base 22 and the pin 23, fixed. See Fig. 7. Similarly, another cutting block 81 for performing the distal bone incision is attached and a second 83 and third 82 connecting element with the

Cut guide device 10 fixed. About anchor holding elements 101 is the fixing device and thus the distal position of the cutting guide device 10th

fixed.

In a revision surgery, a distal purging cut is usually performed first by means of the distal cut block 81. Then the

Cut guide 10 flush with the distal

Cut introduced. This will be a fourth

Connection element 102 is solved on the fixing device 100. To perform the posterior cut, as shown, a saw blade 84 is guided along the anterior cutting plane of the anterior cutting block 12. The Anterior slice plane is usually tilted up to remove as little bone material as possible. to

Guiding the posterior cut can optionally include a posterior incision 80 by means of a first

Connecting element 86 are attached to the posterior cutting block 13. This prevents slippage of the

Saw blade 84 ¹ .

To perform a distal oblique cut 87, the cutting guide device 10 of the

Fixing device 100 dissolved and removed together with the rod-shaped element 85 of the femur bone 69. An incision block for the anterior oblique cut 87 is held only by the fixation device 100.

The fixation device 100 is shown in more detail in FIG. An anchor 103 extending over the medial lateral extent of the femur bone is perpendicular to the intramedullary canal 114 which is approximately aligned with the axis of the femoral bone

Reamer 113 is shown aligned. About holes 106 anchor-holding elements 101 are connected to the femur bone 69. Alternatively, the armature 103 may be oriented and fixed via the incision guide device 10, which is aligned with the rod-shaped element 85 or the reamer 113 attached thereto on the intra-medullary canal 114. Via a fourth connecting element 102, which engages through a groove 107 in the armature 103 and is connected to a guide rail 105, is a displaceable connection between armature 103 and

Guide rail 105 given. By way of a coupling shaft 112, for example, a second cutting guide element 81, which is oriented perpendicular to the coupling shaft 112, is fastened. In order to allow a displacement of the coupling shaft 112 relative to the armature 103 in the case of a fixed incision device 10 in a distal or proximal direction, the coupling shaft 112 and the guide rail 105 are in the exemplary embodiment a non-zero angle, which is the

Varus angle α corresponds, inclined.

For further attachment of the armature 103 to the femur bone 69, the lateral areas 108 of the armature 103 located in the medial-lateral direction are inclined posteriorly. The holes 106 in the inclined side region 108 receive additional armature holding elements 101, which as

Depth stop for the saw blade at certain

Serve bone sections. The sensing bar 109 may optionally be inserted into the coupling shaft 112 and serves to scan the anterior bone and thus to properly position the anterior-incision of the incision guide device. When the stylus 109 contacts the femur anteriorly, the anterior incision with the inclined saw blade 84 and thus the anterior discharge of the femoral component will be at the correct height. Scale 111 adjusts the selected size of the femoral implant. The stylus 109 must be set on the scale 111 on the mark corresponding to the femoral implant size.

All described and / or drawn features can be advantageously combined with each other within the scope of the invention. The invention is not limited to that described

Embodiment limited.

Claims

claims

1. A device for performing bone cuts on the distal femur bone in knee arthroplasty with a base body (11),

marked by

an anterior cutting block (12) arranged on the base body (11), which defines an anterior cutting plane (14), and a posterior cutting block (13) arranged on the base body (11), which is a posterior

Cutting plane (16) determines the distance between the anterior cutting plane (14) and the posterior

Cutting plane (16) is variable.

2. Device according to claim 1,

characterized,

that a change of the distance (19) between the

Anterior cutting plane (14, 14) and one to

parallel base plane (15) through the main body (11) with a change (20) of the distance between the posterior cutting plane (16, 16 ') and the base plane (15) is connected and

that the change of the distance (19) of the anterior

Section plane (14, 14 ') to the base plane (15) and the

Changing the distance (20) of the posterior cutting plane (16, 16 *) to the base plane (15) have a fixed relationship to each other.

3. Apparatus according to claim 1 or 2,

characterized,

the base body (11) has a display (18) indicating the adjustment of the distance between the anterior and posterior cutting planes (14, 16) corresponding to a size of a femoral implant.

4. Device according to one of claims 1 to 3,

characterized,

that a scale (25, 25 ') is attached to the anterior cutting block (12), which is the medial-lateral width of a

Femoral implant indicates.

5. Device according to one of claims 1 to 4,

characterized,

that the anterior incisor (12) and the posterior

Cutting block (13) by an intermediate element (41) are connected, wherein the intermediate element (41) has two threads (52, 53) with opposite direction of rotation and different pitch.

6. Device according to claim 5, characterized

characterized,

the intermediate element (41) is rotatably mounted in the base body (11) and fixed in the axial direction.

7. Device according to claim 5 or 6,

characterized,

in that the intermediate element (41) has a recess (26 ') for receiving an adjusting tool.

8. Device according to one of claims 1 to 7,

characterized,

a posterior incision guide (80) is releasably attachable to the posterior incision block (13).

9. Device according to one of claims 1 to 8,

characterized,

in that the base body (11) has a first recess (21) in which a sleeve (60) is releasably fixed.

10. Device according to claim 9,

characterized,

the recess (21) extends through a non-zero angle to the perpendicular (28) of an end face (9) of the base body (41) in the medio-lateral direction, inclined through the base body (41).

11. Device according to claim 9 or 10,

characterized,

a rod-shaped element (85) is held in the sleeve (60).

12. Device according to claim 11,

characterized,

in that the rod-shaped element (85) is introduced and held in the intra-medullary canal (114) of the bone (69).

13. Device according to one of claims 9 to 12, characterized in that

the base body (41) is fixed to the sleeve (60) at a non-zero angle (β) about an axis through the center (61) of the sleeve (60).

14. Device according to one of claims 1 to 13, characterized

in that a handle (67) can be fastened to the base body (11) and can be fastened in the medial and lateral direction over the

End face (9) of the base member (11) protrudes.

15. Device according to one of claims 9 to 13, characterized the sleeve (60) is fixed in its position on the base element (11) by a retaining pin (29) which can be introduced into the recess (21) of the base body (11).

16. Device according to claim 15,

characterized,

a rod-shaped element (85) is held eccentrically but parallel to the sleeve axis (61) in the sleeve (60).

17. Device according to claim 16,

characterized,

in that the sleeve (60) is rotatable about the axis (64) of the rod-shaped element (85).

18. Device according to one of claims 1 to 20, characterized in that

that the anterior cutting block (12) one over the

Anterior cutting plane (14) attaching, facing in the proximal direction has base (22), with a

Fixing element (100) is connected.

19. Device according to claim 18,

characterized,

in that the fixation element (100) is firmly connected to the femur bone (69).

20. Device according to one of claims 1 to 19, characterized

in that the anterior cutting block (12) has a pin (23) pointing in the anterior direction into which a further cutting block (81) engages.