WO1999021497A1

WO1999021497A1 - Method and instruments for repairing endochondral and osteochondral defects

Info

Publication number: WO1999021497A1
Application number: PCT/CH1998/000430
Authority: WO
Inventors: Roland Peter Jakob; Emanuel Gautier; Christoph Saager; Pierre Mainil-Varlet; Manfred Zech; Werner MÜLLER-GLAUSER
Original assignee: Sulzer Orthopädie Ag
Priority date: 1997-10-27
Filing date: 1998-10-07
Publication date: 1999-05-06
Also published as: EP1027001A1; JP2001520911A

Abstract

Endochondral or osteochondral defects, especially joint cartilage defects are repaired by making cylindrical holes (21) in the area of the defect and implanting columns of tissue (2) with a vital cartilage layer (2') on one front surface, said columns of tissue (2) being taken for example from a less strained joint site. The chances of success of this type of reparation are improved by increased precision. To this end, a guiding instrument for precisely guiding cutting or boring instruments is used for making the holes (21). Said guiding instrument can be positioned and fixed in the area of the defect. Consequently it is possible to achieve a high degree of precision in terms of the parallelity and the position of the holes (21). It is also possible to reconstruct an original cartilage surface very accurately by determining an original cartilage surface and then matching the axial length and the angle between the cartilage surface and the column axis of the column of tissue (2) to be implanted to this original surface. Gaps between the implanted tissue columns (2) and on the edges of the defect in the reconstructed cartilage surface are also filled using another implant from a layer of cartilage (50) grown in vitro.

Description

Methods and instruments for repairing endochondral and osteochondral defects

The invention is in the field of medical technology and relates to methods and instruments according to the preambles of the corresponding claims. The methods and instruments are used to repair endochondral and osteochondral defects, in particular defects that affect articular cartilage or articular cartilage and underlying bone tissue.

Defects in the articular cartilage or defects that affect the articular cartilage and underlying bone tissue are repaired according to the prior art by filling them with artificial, possibly vital cells-containing materials, by implanting in vitro grown cartilage tissue or by cartilage tissue in intact, advantageously unstressed areas removed and implanted as an auto-graft at the defective site, in particular the auto-grafts are mostly columns with an outer end of the cartilage and an inner end of the bone. In the case of larger defects, a plurality of such columns are usually implanted side by side in a mosaic-like manner. For implanting tissue columns, cylindrical openings are defined as precisely as possible in the area of the defect, a tissue cylinder being punched out or drilled out and then separated by turning at its base, or a cutting drill being used. Tissue columns are then removed from an unloaded joint (for example, the condylar region of the femur), the diameter of which is slightly larger than the inside diameter of the openings in the area of the defect. The tissue columns to be removed are drilled out with a hollow drill and then separated by turning the base. The removed tissue columns are then inserted into the defect openings, whereby a so-called "press fit" is created thanks to the different diameters, by means of which the columns are held in the openings. The openings resulting from the removal of the columns are usually filled with the material which has been removed from the defect, if this material is in good health, or they are closed by inserting artificial materials or material grown in vitro.

For the detachment and removal of the tissue columns to be implanted and possibly also for punching or removing the tissue from the openings in the defect area, tubular instruments are usually used, which have an annular cutting edge on one end face and are equipped for holding and guiding at the other end . To check the length and quality of the punched-out tissue column, such an instrument advantageously has corresponding windows. The punched material is cut to the inside diameter of the

Instruments matched plugs pushed out of the tubular instrument. Such instrument sets are available on the market, manufactured for example by Smith & Nephew. Inc., USA, or from Arthrex Inc., USA. Flat drills can be used to create the openings in the defect area by drilling. It has been shown that the success of the above-mentioned methods for repairing articular cartilage defects by implanting vital tissue depends to a large extent on the precision with which the repair tissue is used and also on the treatment that the tissue takes when it is removed and exposed during implantation.

For this reason, the invention is based on the object of known methods and instrument sets for repairing cartilage defects or defects affecting cartilage and underlying bone tissue, in particular articular cartilage defects, by implanting or transplanting vital tissue in the form of a column in order to increase the chances of success to improve. The methods and instruments according to the invention are intended to make it possible to increase the precision of the repair while at the same time treating the manipulated tissue very gently. The instruments according to the invention should nevertheless be easy to manufacture and, in particular, easy to handle. The methods and devices according to the invention should in particular be suitable for repairing larger defects using a mosaic method, but of course they should at least partially also be applicable for small defects that can be repaired with only one implant.

This object is achieved by methods and instruments as defined in the independent patent claims. The dependent claims define further embodiments.

It turns out that improvement efforts for four sub-aspects are necessary to solve the above-mentioned general task, depending on the application one of the improvement aspects has the greatest effect and the other aspects have a small effect or without noticeable effects Are effective and can therefore also be omitted. The four main improvement aspects are as follows:

When a plurality of tissue columns are implanted, the precision of the positioning and parallelism of the cylindrical openings produced in the region of the defect is increased. This is accomplished by creating the openings using appropriate gauges. This measure generally prevents tissue columns implanted in the openings from pressing against one another and thereby being exposed to additional loads, and it is ensured that each implanted column is at least in the area in which it is anchored in healthy tissue as completely as possible from native Tissue is surrounded, which improves wound healing.

- With the cartilage surface of the repaired defect, the topography of the original, i.e. healthy or defect-free cartilage surface is reproduced with improved precision. In order to achieve this goal, the axial length of the tissue columns to be implanted and, if possible, also the orientation of the cartilage surface relative to the column axis are specifically aligned to the cartilage surface to be simulated. This measure is particularly important in the case of relatively large defects that can be repaired with a plurality of implant columns. The better the original cartilage surface is simulated, the more evenly the surfaces of the individual implants are loaded when the repaired joint is used, and the more evenly is the total load distributed to the individual implants. This can prevent undesirable deformations and damage to the implants and the native cartilage around the repaired defect as after-effects of the repair. The cartilage surface of the repaired defect is made more gapless and also connected more seamlessly to the native cartilage. The gaplessness of the cartilage surface is realized with a combination of transplanted or implanted tissue columns with in vitro grown cartilage tissue, with the gaps between the implanted

Tissue columns and possibly also gaps between the tissue columns and the native cartilage are filled. A gapless cartilage surface encourages the implant and native cartilage to grow together and prevents consequential damage that can occur due to the fact that synovial fluid due to gaps in the

Cartilage layer reaches the underlying bone tissue. This measure is also important for larger defects that can be repaired with a plurality of graft columns, while the "press fit" already mentioned at the beginning is sufficient for small defects.

The material to be implanted is treated gently during harvesting as well as during implantation and in particular without pressure, so that uncontrolled deformations of the tissue column grafts and possibly the implant parts grown in vitro are avoided and the precision of the repair is also improved thereby.

The implanted tissue columns are advantageously autotransplants removed from an unloaded area for all cases, but can also consist of a bone substitute material on which cartilage tissue was previously grown in vitro. Such columns to be implanted are also advantageously produced during the repair operation from appropriately prepared pieces by punching out or drilling out (hollow drill). The methods and instruments according to the invention are suitable both for repair operations which are carried out as open surgery and for arthroscopy.

In connection with the following figures, exemplary embodiments of the improved method and the improved instrument sets for repairing endochondral or osteochondral defects, in particular in joints, will now be described in more detail. Show:

Figure 1 is a schematic representation of a known

Mosaic method repaired cartilage defect as a top view and in section to explain the improvement aspect of the precision with regard to positioning and parallelism of the openings created in the area of the defect,

FIG. 2 shows an exemplary embodiment of a teaching for creating the openings in the area of a defect to be repaired according to FIG. 1,

FIG. 3 shows a schematic representation of a cartilage defect to explain the improvement aspect of the reconstruction of the original cartilage surface by means of the corresponding axial length of tissue columns to be implanted and an example of a teaching for the reconstruction of the original cartilage surface,

FIG. 4 shows an exemplary embodiment of an instrument for determining the distance between the original cartilage surface and the base area of a created opening in the area of a defect to be repaired according to FIG. 3, Figure 5 and

6 shows schematic representations of a cartilage defect (FIG. 5) and a removal point (FIG. 6) to explain the

Aspect of improvement of the reconstruction of the original cartilage surface by appropriate adjustment of the angle between the cartilage surface and the axis of a tissue column to be implanted,

FIG. 7 shows an exemplary embodiment of an instrument for removing and implanting tissue columns with a predetermined angle α between the cartilage surface and the column axis,

8 shows a teaching according to FIG. 2 equipped for the implantation of tissue columns in a predetermined rotational position,

Figure 9 and

10 shows schematic representations of a repaired cartilage defect as a top view (FIG. 9) and in section (FIG. 10) to explain the improvement aspect of the gaplessness of the repaired cartilage surface,

FIG. 11 shows an exemplary embodiment of a punching tool for producing an implant from cartilage tissue grown in vitro for a repair according to FIGS. 9 and 10, Figure 12 shows an exemplary embodiment of an instrument for

Determination of the layer thickness of cartilage grown in vitro,

13 to 16 show an exemplary embodiment of cooperating instruments (FIGS. 13 to 15 in section parallel to the axis) for the gentle removal and implantation of tissue columns,

FIG. 17 the instruments according to FIGS. 13, 15, 16 in a three-dimensional representation,

Figure 18 shows an embodiment of an implant guide with recesses in the end face for receiving a stop pin provided on the extractor

and

Figure 19 shows an embodiment of a ram for ejecting a column of tissue from the extractor.

FIG. 1 shows a cartilage defect repaired according to the known mosaic method as a top view (left) and in section (right). The top view shows the surface of the native cartilage layer 1 and the round surfaces of the cartilage layers 2 'of those implanted for the repair

Tissue columns 2. On average, the native bone tissue 3 lying under the native cartilage layer 1 is also visible and the tissue columns 2 implanted in corresponding cylindrical openings, which have an inner bone part 2 "under the cartilage layer 2 ', which in the case of transplanted columns of bone tissue, in the case of in vitro grown columns of a bone substitute material.

In order to be able to achieve a repaired cartilage surface with the smallest possible gaps or with the smallest possible areas of defective cartilage material, the aim is usually to arrange the columns as closely as possible. For this reason, it is important that the openings for the columns 2 to be implanted run as parallel as possible. With a high degree of parallelism, it can be ensured that the openings can be made very close to one another without overlapping, which would make implantation more difficult and create additional loads on the implanted columns. If, as will be described in connection with FIGS. 9 and 10, the spaces between the columns 2 are to be filled with a further implant, not only is high precision necessary with regard to the parallelism of the openings to be created but also with regard to the positioning of the openings .

FIG. 2 shows an exemplary embodiment of a guiding instrument, with the aid of which a plurality of cylindrical openings can be created in the region of a cartilage defect with a significantly higher precision than the surgeon's eye, as has been done up to now. The exemplary embodiment of the guiding instrument shown is suitable for realizing a repair as shown in FIG. 1. It essentially consists of a hollow cylindrical ring guide 10 and at least two tubular punching or drilling guides 11 and 12, all of which are shown as a top view (like the top view of the repaired defect on the left in FIG. 1).

The ring guide 10 is positioned surrounding the defect and, for example, with the help of Kirschner wire which passes through the holes 13 or attached with another suitable fastener. It should be selected from a set of ring guides whose inner surface is of such a shape and size that it is matched as precisely as possible to the defect to be repaired. The punching or drilling guides 11 and 12 have an inner diameter which is adapted to a punching or drilling instrument to be used and, for exact positioning in the ring guide 10 on the outside, have, for example, at least one axially extending comb 14 which fits into the inside surface of the Ring guide 10 axially extending grooves 15 fits, the radial height of the comb or combs 14 being adapted to the distance between the inner surface of the ring guide 10 and an opening to be created. In FIG. 2, the punching or drilling guide 10 is intended for creating the central opening of the repair shown in FIG. 1, the punching or drilling guide 12 for creating the peripheral openings.

Both guides 11 and 12 have two combs 14 which can be positioned in mutually opposite grooves 15 of the ring guide 10. With a corresponding design of grooves and combs, it is also possible to provide only one comb for each punching or drilling guide.

The guide instrument shown in FIG. 2 is intended for an approximately circular defect. In the same way, guiding instruments for differently shaped defects can be provided.

The ring guide 10 of the guide instrument according to FIG. 2 is fastened, for example, with Kirschner wire positioned around the defect to be repaired. In order to avoid additional stresses on the defect area due to the attachment of the ring guide 10, the ring guide 10 can also be attached, for example by means of a three-point fixation, to a fixing point remote from the defect point on the bone on which the Defect is to be repaired. Such attachments are known from joint prosthesis surgery. They can be used for both open surgery and arthroscopy.

So that the view of the surgeon is hampered as little as possible during the creation of the openings, at least the ring guide 10 advantageously consists of a transparent material or has corresponding windows.

The guide instrument shown in FIG. 2 represents an exemplary embodiment of such an instrument. In general, such a guide instrument has means with which it can be positioned in the area of a defect to be repaired, and has means for guiding punching or drilling instruments on one Majority of positions.

An inventive set of instruments for the repair of

In addition to the punching or drilling instruments for creating the openings for the implantation of the tissue columns, cartilage defects have a set of different guiding instruments which may be adapted to the joint to be treated and the defect to be expected. The surgeon performing the repair selects the appropriate one from the set of guide instruments, positions the ring guide 10 on the defect and fixes it. Then he inserts a punching or drilling guide 11 or 12 into the ring guide 10 and uses it to guide the punching or drilling instrument used to create a corresponding opening. To create additional openings, the punching or drilling guide is exchanged or its position changed.

Figure 3 shows a cartilage defect 20 at a strongly curved joint point in section. Defects of this size are not uncommon at knee and hip joints. The defect 20 and three in the area of the defect, for example Openings 21 created in the guide instrument according to FIG. 2 are shown in solid lines. The original cartilage surface 22, which is to be reproduced as accurately as possible by the repair, is indicated by a dash-dotted line. FIG. 3 clearly shows that a measurement of the depth of the openings made in the defective area to determine the axial length of the tissue columns necessary for the repair is a poor approximation.

To improve the approximation, it is proposed to approximate the original cartilage surface 22 with the aid of a shape gauge 23. Before the openings are created, various gauges 23 of this type are used to select the gauge 23 that best fits the defective cartilage area from a corresponding set of gauges.

The gauges 23 of the gauge set can, for example, be simple, one-dimensional radius gauges through which the original

Cartilage surface 22 is approximated as a spherical surface. However, one-dimensional or two-dimensional gauges 23 are also conceivable for customary sizes and shapes of certain joint areas.

Figure 4 shows an exemplary embodiment of an instrument for

Determination of the axial lengths of tissue columns for implantation into the openings 21, which have been created in the defect 20 according to FIG. 3. The representation is the same as in Figure 3 and the instrument for determining the column lengths is shown in an axial section. The instrument essentially consists of a ring guide 10, a surface template 24 and a measuring rod 25.

If the openings have been created with the aid of the guide instrument according to FIG. 2, the ring guide 10 of this instrument advantageously serves as a ring guide for determining the length. There will be one Positioned surface template 24. This surface template 24 is the template from a set of differently shaped templates 24, which corresponds to the teaching 23 selected prior to the creation of the openings for the reconstruction of the original cartilage surface 22 in its shape (curvature), and it has a pattern of measuring openings 26 which corresponds to this Pattern of the created openings 21 corresponds. For example, with positioning cams 27 that fit into the grooves 14 of the ring guide 10, the measurement openings 26 of the surface template 24 are aligned with the pattern of the openings 21.

It is also conceivable that the measuring template 24 is also used directly as a shape gauge 23. In this case it is advantageous if it consists of a transparent material.

The measuring rod 25 has a diameter matched to the measuring openings 26 and a measuring scale 28 which takes into account the distance between the original cartilage surface 22 and the measuring template 24. The necessary length of the tissue columns to be created for the repair can be read directly on the measuring scale 28, for example to within half a millimeter.

For a simple assignment of each form gauge 23 of a set of gauges to a specific measurement template 24 of a set of templates, these are to be designated accordingly, which can be implemented, for example, with a color code. Since the measuring templates 24 run parallel to an original cartilage surface 22 and the distance between this surface and the measuring template essentially corresponds to the axial height of the ring guide 10, one measuring rod 25 is sufficient for all measurements. So that openings with an oblique angle between the opening axis and the original cartilage surface 22 (peripheral openings of the defect according to FIG. 3) can be ensured that the same opening depth is always measured, The measuring rod 25 and the measuring openings 26 can be provided with axially extending grooves and ridges (not shown in FIG. 4), by means of which the measuring rod 25 can only be inserted into a measuring opening 26 in a defined rotational position.

The instruments according to FIGS. 3 and 4 for determining the original topography of a defect area and for determining the lengths of tissue columns for repairing the defect are exemplary embodiments. In general, such instruments have form gauges for determining the topography and means adapted to the form gauges for determining the column lengths, wherein the form gauges themselves can be part of the means for determining the column lengths.

A surgeon who has to repair the defect shown in FIG. 3 proceeds in the following steps:

Determination of the surface template 24 corresponding to the defect, if necessary with the aid of a gauge 23;

Position and assembly of the ring guide 10;

Creating the openings 21, if necessary, with the help of the guides 11 and 12;

Position the surface template 24 and determine the axial

Lengths for tissue columns to be implanted;

Adjustment of punching or drilling instruments for the removal of tissue columns to the predetermined axial length; - Removal of the columns at an extraction point and implantation in the

Openings.

Figure 5 shows the same defect as Figure 3 at a strongly curved joint. It is evident from FIG. 5 that the original cartilage surface 22 can be reconstructed with a higher precision if the Angles α.1, α.2 and α.3 between the original cartilage surface and the axis of the openings 21.1, 21.2 and 21.3 are not left to chance, but are specifically reconstructed. It is therefore advantageous for increased chances of success of the repair to determine the angles α for the differently implantable tissue columns and to remove the tissue columns in a targeted manner from another location or to punch them out of a cartilage grown in vitro.

The simplest thing would be to look for a removal site for the removal of tissue columns to be transplanted, which has the defective shape

Area corresponds, and the tissue columns in an arrangement that is identical to the arrangement of the openings created in the defect area.

Not only is this not advantageous, it is actually not possible. to

In particular, the less stressed condylar region of the femur, which has its own shape, is available for removal, and it is advantageous to perform the withdrawals in a row and to keep the distances between the removal sites as large as possible.

For this reason, the angles α have to be determined for a precise reconstruction of the original cartilage surface 22 and the columns have to be removed at the removal point at a corresponding angle.

FIG. 6 shows such a removal point and the tissue columns 2.1, 2.2 and 2.3 to be removed, corresponding to the openings 21.1, 21.2 and 21.3, for which the angles α between the cartilage surface and the column axis are

Correspond to angles α.1, α.2 and α.3.

For the removal of the tissue columns 2.1, 2.2 and 2.3 according to FIG. 6 and for their implantation into the openings 21.1, 21.2 and 21.3 according to FIG. 5, an instrument is to be provided with the aid of which a column with a predetermined one is provided Angle between the column axis and the cartilage surface and can be removed in a defined rotational position and can be implanted in a likewise defined rotational position.

Figure 7 shows an exemplary embodiment of such

Removal instrument, which consists essentially of an extractor guide 30 and an extractor 31.

The extractor guide 30 is essentially tubular and has at one end a support flange 32 which is aligned at an angle α to the tube axis. Although an exemplary embodiment is shown in FIG. 7 in which the angle α to the pipe axis is fixed, it goes without saying that the instrument can also be designed such that this angle α can be set. The support flange 32 can have holes (not shown) for its attachment, through which it can be nailed to the tissue with Kirschner wire. An external three-point fixation, as already mentioned in connection with FIG. 2, is also possible for fastening the extractor guide.

The extractor guide 30 has an inner diameter matched to the extractor 31 and a guide groove 33 which runs axially on the inner surface and runs, for example, at the point on the inner circumference corresponding to the highest or lowest point of the support flange 32. In an enlarged end region 34 of the extractor guide 30, which opens into the support flange 32, the inside diameter is on the radial extension of the guide groove

33 expanded.

The extractor 31 is also tubular and has an inner diameter which corresponds to the diameter of the column to be removed. One end is pointed like a blade. On its outer surface, the Extractor 31 has a guide cam 35 which runs in the guide groove 33 of the extractor guide 30 when the extractor 31 is inserted into the extractor guide 30. This guide cam 35 is arranged axially in such a way that it is positioned in the enlarged end region 34 of the extractor guide 30 when the tapered end face of the extractor 31 has reached the depth in the tissue which corresponds to the length of the column to be removed. Thanks to the guide cam, the extractor 31 can only be inserted into the extractor guide 30 in a defined rotational position, but can be rotated at its base in the extractor guide in order to detach the column.

So that the column to be detached does not rotate in the extractor 31 when it is detached by turning, the extractor has at least one axially extending and advantageously cutting-like rotary stop 36 on its inner surface as close as possible to the tapered end face, projecting radially into the inner cavity. It turns out that the radial extent of such a rotation stop need not be greater than one millimeter.

The extractor 31 guided through the extractor guide 30 can be used to punch out a column of tissue, as indicated by the lines S, and to detach it by rotating its base. Advantageously, however, before

Extraction of the column with a hollow drill (not shown) pre-drilled along the lines S. Such a hollow drill corresponds in shape to the extractor 31, the guide cam 35 and the rotary stop 36 being missing. The tapered edge is advantageously made of a diamond-containing material or coated with such a material. The drill also has suitable means for determining the drilling depth.

FIG. 7 also shows a plunger 37 for ejecting an extracted tissue column from the extractor 31. Advantageously, the plunger has a distal end face which, like the support flange 32, unites with the plunger axis Forms angle α. So that the plunger 37 can only be inserted into the extractor in the rotational position corresponding to the flange position, it has an axially extending guide groove 38 and the extractor 31 has a corresponding guide comb 39, which, however, does not extend into the area of a tissue column positioned in the extractor. The distal end of the plunger 37 has a reduced diameter so that it can be pushed past the rotary stop 36 to the end of the extractor 31.

FIG. 8 shows an implantation instrument for implanting the tissue column removed with the removal instrument according to FIG. 7. The instrument is shown as a top view. This is an implantation guide 40 which is configured in the same way as the punching or drilling guides 11 and 12 in FIG. 2 and can be positioned in the same ring guide 10 (indicated by a dash-dotted circular line). The inside diameter of the implant guide 40 is matched to the outside diameter of the extractor 31. So that the extractor 31 can only be inserted into the implantation guide 40 in the predetermined rotational position, the latter has an axially extending guide groove 41 on its inner surface, in which the guide cam 35 of the extractor 31 can be positioned.

The angles α of the tissue columns to be implanted are clearly determined for each column by the shape of the previously selected surface template 24 (FIG. 4). It is therefore sufficient to provide the surgeon with a removal instrument with a set of different extractor guides 30, which can be correlated, for example, with a code with the corresponding measurement opening of the surface template or with the corresponding opening created in the defect area. Different numbers of lines for different pairs of measuring openings and extractor guides for a surface template to be correlated are conceivable as a code, the lines for different surface templates having different colors. The Extractor guides 30 can also be designated by the size of the angle α and the same sizes can be noted on the surface templates next to the measurement openings.

The instruments according to FIGS. 7 and 8 represent examples

In general, a removal instrument for a column removal with a predetermined angle between the cartilage surface and column axis at a removal point fixable means for guiding an extractor and possibly a hollow drill at the predetermined angle and an implantation instrument, the removal instrument and implantation instrument correlated means for a removal and Have implantation in a correlated rotational position.

In order to reconstruct the angles between the column axes and the original cartilage surface, a surgeon will therefore read from the surface template 24 which extractor guide 30 he has to use to remove each column of tissue. He assembles the extractor guide 30 at a suitable extraction point, he drills the tissue column through the extractor guide 30 with internal and external cooling, he drives an extractor 31 into the pilot hole, detaches the tissue column from its base by rotating the extractor, and rotates the extractor 31 back to its original rotational position and removes the extractor 31 with the tissue column from the extractor guide 30. Then he puts the implant guide 40 in the ring guide 10 still mounted on the defect area, pushes the extractor with the tissue column into the implant guide 40 and pushes the tissue column with it With the aid of the plunger 37 into the opening positioned under the implant guide, which he previously created, as was described, for example, in connection with FIGS. 1 and 2. The axial length of the tissue column removed is determined per se if means are provided with which the drilling depth and the insertion depth of the extractor into the tissue can be adjusted. Nevertheless, it may be advantageous to check this length before the implantation and correct it if necessary. For this purpose, 31 windows (see also FIGS. 13 and 17) are provided in the extractor, which are arranged such that the cartilage surface of the removed column comes to lie in the area of the windows, and length scales in the area of the windows, with the aid of which the distance between the tapered edge of the extractor and the cartilage surface of the tissue column can be determined. If the tissue column removed is too long, it is pushed forward slightly with the aid of the ram 37 and the part protruding from the extractor is cut off.

FIGS. 9 and 10 show a top view and in section of a repaired cartilage defect which, in addition to implanted tissue columns 2, has an implanted cartilage layer 50 grown in vitro. The cartilage layer 50 fills the gaps between the tissue columns 2 and those between the tissue columns 2 and the native cartilage layer 1. The implanted cartilage layer 50 is where the defect is deeper than the thickness of the cartilage layer 50 backfilled with a suitable filling material 51.

The main advantage of the repair according to FIGS. 9 and 10 with an implanted cartilage layer 50 compared to the repair according to FIG. 1 without such a cartilage layer is that with the cartilage layer 50 the gaps between the implanted tissue columns 2 are completely closed, as a result of which synovial fluid penetrates the bone tissue can be prevented. As a result, the columns can also be implanted a little further apart, so that they are completely surrounded by native bone tissue, which considerably accelerates the complete adhesion of native and implanted tissue. The advantage of the repair according to FIGS. 9 and 10 with implanted cartilage layer 50 and transplanted tissue columns compared to a repair that only has an in vitro grown cartilage layer (possibly backfilled with a suitable material) is that the transplanted cartilage, which is also a has sufficient mechanical strength, a large part of the load is taken over, so that immediately after the repair operation, the in vitro grown cartilage matures with care (little strain) and can thus achieve its final mechanical strength, which is equivalent to the native cartilage.

The cartilage layer 50 is previously grown from autologous cells either on a base made of a bone substitute material or without such a base. The shape of the resulting cartilage is determined by the space that is made available to the cells during cultivation.

For an implantation, the in vitro grown cartilage layer 50 must be punched or cut as precisely as possible into the shape that corresponds to an opening made in the area of the defect to be repaired, and openings for the tissue columns must be created therein, which openings in turn for a "press fit "should have a slightly smaller diameter than the fabric columns. Furthermore, the thickness of the grown cartilage layer must be determined for a precise backfilling of the cartilage layer or for a corresponding cutting out of the defect.

To create the opening for the cartilage layer 50 to be implanted, for example, a ring guide 10 (FIG. 2) is mounted in the defect area and the native cartilage tissue is cut vertically along it with a corresponding ring punch instrument or with a scalpel and then removed or removed against the defect, in such a way that within the The guidance of the cartilage or bone surface is deeper than the original cartilage surface by at least the thickness of the cartilage layer to be implanted.

A repair with six rotationally symmetrically arranged tissue columns 2 is shown in FIGS. 9 and 10. Of course, other column arrangements with different numbers of tissue columns, in particular also with only one tissue column, can be carried out in the same way.

FIG. 11 shows an exemplary embodiment of a punching instrument for producing a desired implant from the cartilage layer 50 for a repair, as is shown in FIGS. 9 and 10. The punching instrument essentially consists of a support surface 60 and a die 61. The shape (curvature) of the support surface 60 advantageously corresponds to the shape of the cartilage surface 22 to be reconstructed (FIGS. 3 and 4) or the surface template 24 (FIG. 4), according to which the Cartilage surface is reconstructed. The punching die 61 has a shape corresponding to the support surface 60 and has punching blades 62 corresponding to the outline of the implant to be created and the openings to be made for tissue columns, the punching blades having a width which is greater than the thickness of the cartilage layer to be punched.

To produce an even more precise punching, it is advantageous to mount counterblades (not shown) of a very small width corresponding to the punching blades 62 of the punching die 61 on the support surface 60.

The grown cartilage layer 50 is positioned on the support surface 60 and the die 61 is moved in parallel against the support surface 60 by means of suitable drive means until the punch blades 62 on the support surface 60 or rest on the counterblades and the cartilage layer 50 is completely severed at the intended locations.

FIG. 12 shows an exemplary embodiment of an instrument for determining the thickness of a cartilage layer 50 grown in vitro (with or without a base layer made of bone substitute material). The instrument essentially consists of a measuring block 70 with indentations 71 of different depths and a weighting block 72, which advantageously consists of a transparent material and whose weight per contact surface essentially corresponds to the pressing force used during the implantation. The depressions 71 advantageously have the shape of a defect to be repaired or the shape of an opening which has been created in the region of such a defect for the implantation of the cartilage layer 50.

For a thickness determination, the punched out cartilage layer 50 is placed in one of the depressions 71 and weighted down with the weighting block 72. The thickness of the cartilage layer 50 relevant for the implantation corresponds to the depth of the depression 71 on which the weighting block 72 is no longer resting when the cartilage layer 50 is positioned therein.

An instrument set according to the invention for repairing a defect according to FIGS. 9 and 10 thus has, in addition to at least some of the instruments already described, an instrument for punching or cutting an in vitro grown cartilage layer 50 with a set of different pairs of support surfaces 60 and punching dies 61. Furthermore, the set of instruments advantageously has an instrument for measuring the thickness of such a cartilage layer that is relevant for the implantation, or a set of such instruments for different types of defects. For a repair as illustrated in FIGS. 9 and 10, a surgeon carries out, for example, the following steps in the order given:

Determining the shape of the cartilage surface 22 to be reconstructed;

Determining the opening for the cartilage layer 50 to be implanted and the pattern of the tissue columns 2 to be implanted;

Producing the implant from an in vitro grown cartilage layer 50 and determining the thickness of the cartilage layer 50;

Assembly of a ring guide 10;

Creating the opening for the cartilage layer 50 to be implanted; - For each tissue column 2: create an opening 21, remove one

Tissue column 2, implantation of the tissue column 2 in the opening 21;

Removing the ring guide 10; if necessary, introduction of the filling material 51;

Implant the punched cartilage layer 50.

FIGS. 13 to 16 illustrate (FIGS. 13 to 15 in section parallel to the axis) parts of a further exemplary embodiment of an instrument for removing and implanting tissue columns: FIG. 13 an extractor 31.1, FIG. 14 an extractor guide 30.1 for guiding the extractor 31.1 when the tissue column is removed, FIG. 15 shows an implant guide 40.1 for guiding the extractor 31.1 during the implantation of the tissue column and FIG. 15 shows a plunger 37.1 for ejecting a tissue column from the extractor 31.1.

The instrument parts 31.1, 30.1, 40.1 and 37.1 correspond in many features to the functionally identical instrument parts 31, 30, 40, 37 already described in connection with FIGS. 7 and 8. Only the features in which they differ from these are described here differentiate. Further features are designated by the reference numerals in FIGS. 7 and 8. The extractor 31.1 has, in its region facing the tapered front edge, two windows 80 lying opposite one another and a length scale 81 for the inspection and length measurement of a removed tissue column. Furthermore, the extractor on the side of the window 80 opposite the tapered end edge is divided longitudinally into two extractor parts up to its opposite end by two axially extending slots 82 arranged opposite one another. The end of the extractor opposite the tapered front edge is equipped for easy handling with a handle 83, also divided into two parts, which also limits the depth of insertion of the extractor 31.1 into a corresponding guide 30.1, 40.1.

At this point it should also be noted that the rotary stop 36 shown in FIG. 7 and the two rotary stops in FIG. 13, which prevent twisting of the extractor relative to the tissue column when a tissue column is twisted (after all, the tissue column must be from the floor on which it is located is still "anchored", can be twisted off), can also be made significantly longer than is shown in FIG. 13 or also in FIG. In particular, such a rotation stop 36 can each extend over the maximum length that a tissue column to be removed with the corresponding extractor can have, or even over the entire length of the extractor. Extractors with longer ones

Rotation stops 36 are particularly advantageous when the surgeon or orthopedist has advanced the extractor into the area of the cancellous bone, but the cancellous bone is no longer able to offer the extractor the necessary support to hold the column of tissue from the floor, on which it is still anchored to turn. With a longer rotary stop 36, however, this rotary stop extends in any case into an area of the tissue column that offers sufficient hold to ensure that the tissue column is safely unscrewed even if this is not possible with a short rotary stop 36 due to the nature of the cancellous bone would. The extractor guide 30.1 is not equipped like the extractor guide 30 for a precise removal angle α (FIGS. 6 and 7) and cannot be fixed at a removal point. For this reason, it is not very suitable as a guide for a hollow drill. Rather, their function is to provide the surgeon with a further holding means in addition to the handle 83 for holding the extractor 31.1 during the extraction of a tissue column, in which guide 30.1 the extractor 31.1 can be freely rotated, and at the same time to undesirably spread the two to prevent the slot 82 apart from the extractor parts apart from one another in the region of the tension-pointed end edge.

The implant guide 40.1 is also not equipped to be fixed in the defect area. It also has windows 80 lying opposite one another, through which the rotational position can be determined by aligning the windows in the extractor 31.1 of a tissue column during the implantation. The inner diameter of the implant guide 40.1 corresponds to the outer diameter of the extractor 31.1 only in a distal end region and is otherwise larger than this. This allows the two extractor parts separated by the slots 82 to be spread apart during the implantation. The plunger 37.1 has a conical region 84 for the expansion of the extractor parts mentioned.

By spreading the extractor parts during implantation, the friction between the extractor and the tissue column is reduced and the pressure on the cartilage layer of this tissue column, which is necessary to push it out of the extractor, is reduced, which makes the treatment of the tissue column more gentle.

The plunger 37.1 also has a handle 85, which serves for its convenient handling and at the same time ensures that the plunger can only be pushed up to the pointed end of the extractor 31.1. The features of the instrument parts 31.1, 30.1, 40.1 and 37.1 according to FIGS. 13 to 16 can be combined as desired with features of the functionally identical instrument parts 31, 30, 40, 37 according to FIGS. 7 and 8.

Figure 17 shows the instrument parts 31.1, 40.1 and 37.1 according to Figures 13, 15 and 16 in a three-dimensional representation.

FIGS. 18 and 19 show further exemplary embodiments for an implant guide 40.2 and a plunger 37.2 which are similar to the implant guide 40.1 and the plunger 37.1 from FIGS. 15 and 16. The

The extractor 31.1 and also the extractor guide 30.1 can be kept essentially unchanged in the form shown in FIG. 13 and FIG. 14, but in particular the rotary stops 36 can extend over the entire length of the extractor 31.1.

As can be seen in FIG. 13, the handle 83 has a stop pin 830 projecting downward on its underside. This stop pin 830 is of no further importance for the removal of the tissue column at the harvesting point, except that the extractor guide 30.1 (FIG. 14) can have a corresponding recess 831 for receiving this stop pin 830, which then together with the stop pin represents an anti-rotation device. On the other hand, the stop pin 830 can be of considerable importance if the implant guide is designed accordingly. In order to explain this meaning, the stop pin 830 can have a height of 3 mm, for example, for the following consideration (measured from the underside of the handle 83).

If a tissue column has been removed at the harvesting point with the aid of the extractor 31.1, which is then located in the extractor 31.1 and is, for example, flush with the extractor 31.1 at the bottom, this should be the case Tissue column - as explained earlier - are implanted in a corresponding hole or recess at the defect site. This implantation is carried out in such a way that the tissue column is fitted into the hole at the defect site with a slight press fit ("press fit"). As already explained, it is of particular advantage for the success of such an implantation / transplant if the original shape of the cartilage (i.e. the shape before the defect appears) is reproduced as realistically as possible so that the cartilage again as good as possible after the healing process has its original shape.

To achieve this, it may be necessary, depending on the size of the defect, for the tissue column to either reach the bottom of the hole with the aid of the implant guide 40.2 and the plunger 37.2 (FIG. 18 or FIG. 19) the defect has been created, is pressed in, or that the tissue column has a predetermined distance from the bottom of the bore after the pressing in, so that the original shape of the cartilage can be reproduced as lifelike as possible. Under no circumstances should the tissue column be pressed in deeper than the bottom of the hole. This risk exists especially if the bottom of the hole lies within the (porous) cancellous bone. To achieve or avoid all of this, the surgeon or orthopedist should be given a simple instrument.

For this purpose, the implant guide 40.2 has on its proximal face (FIG. 18) two depressions 832 and 833, for example arranged opposite one another, of which the depression 832 has a depth of 1 mm and the depression 833 has a depth of 3 mm. If, during implantation, the extractor 31.1 (FIG. 13) containing the tissue column is first inserted into the implant guide 40.2 with the stop pin 830. (FIG. 18), the stop pin 830 can be introduced in three different positions relative to the implant guide 40.2. In the first position, the stop pin 830 comes to rest in the recess 833. Since the stop pin 830 has a length of 3 mm in the selected embodiment, but the recess 833 also has a depth of 3 mm, the underside of the handle 83 of the extractor 31.1 comes to lie flat on the proximal end face of the implant guide 40.2.

In the second position, the stop pin 830 comes to rest in the recess 832. This has a depth of 1 mm, so that the underside of the handle 83 of the extractor 31.1 is 2 mm above the proximal

The end face of the implant guide 40.2 comes to rest when the stop pin 830 stands on the bottom of the depression 832.

Finally, in the third position, the stop pin 830 does not come to rest in either of the two depressions 832 or 833, but lies on the proximal end face of the implant guide 40.2. In this position, the underside of the handle 83 of the extractor 31.1 comes to lie 3 mm above the proximal end face of the implant guide 40.2.

The surgeon now has the extractor in one of the three positions

When the implant guide 40.2 is inserted, the implant guide 40.2 is placed at the location of the defect, in such a way that the distal end face of the implant guide 40.2 is placed on the subchondral bone around the hole already created. The plunger of tissue is then pressed out of the extractor into the bore using the ram.

The plunger is basically designed such that when the plunger is fully inserted into the extractor, the underside of the handle of the plunger rests on the proximal end face of the handle of the extractor 31.1. In this state it is distal end of the plunger flush with the distal end of the extractor - the distal end of the plunger has pushed the tissue column completely out of the extractor, but not necessarily completely out of the implant guide 40.2. That depends on the position in which the extractor has been inserted into the implant guide 40.2.

If the stop pin 830 of the extractor is immersed up to the stop in the recess 833 of the implant guide 40.2 (first position), then the plunger 37.2 has also pushed the tissue column completely out of the implant guide 40.2 (because the distal end of the extractor is then also flush with the distal end the implant guide) and has therefore normally pushed the tissue column to the bottom of the hole at the location of the defect, the tissue column does not protrude above the subchondral bone.

If the stop pin 830 of the extractor 31.1 is immersed up to the stop in the recess 832 (second position), the plunger completely immersed in the extractor has pushed the tissue column completely out of the extractor 31.1, but not completely out of the implant guide 40.2 (because it is flat the distal end of the extractor is not flush with the distal end of the implant guide), and there still remains a length of 3 mm (length of the stop pin 830) minus 1 mm (depth of the bore 832), i.e. a length of 2 mm, by which the tissue column still protrudes into the implant guide 40.2. The tissue column then also protrudes from the subchondral bone by this amount, but this can be desirable for larger defects in order to faithfully reproduce the shape of the original cartilage.

If the stop pin 830 stands on the proximal end face of the extractor 31.1 (third position), there is a corresponding amount of 3 mm by which the tissue column is still in the implant guide when the plunger is fully inserted 40.2 protrudes or protrudes above the subchondral bone at the location of the defect. It is clear that these values for the depth of the depressions 832 and 833 are only to be considered as examples, of course other values are also possible. The surgeon or orthopedist can then decide, depending on the circumstances at the location of the defect, how far he wants to press the tissue column into the hole.

The plunger 37.2 shown in FIG. 19 now has a special feature in comparison to the plunger 37.1 (FIG. 16). The handle of the plunger 37.2 namely comprises two parts, an upper handle part 851, which is fixedly connected to the shaft of the plunger, and a lower handle part 852, which can be moved along the shaft and whose outer wall is conically tapered when viewed in the distal direction. This lower grip part 852 can be moved along the shaft up to a bead 853 at most. When the stem of the plunger 37.2 is inserted into the extractor 31.1, the lower grip part 852 can be moved into the extractor and can easily expand the extractor 31.1, which has longitudinal slots, with the help of its conical outer surfaces. However, the lower handle part 852 can only be advanced until the underside of the lower handle part 852 bears against the proximal end face of the handle 83 of the extractor 31.1. In the case of the extractor 31.1 which is slightly spread in this way, this is further

Pressing out the column of tissue or pressing the column of tissue into the hole is facilitated because the slightly spread extractor makes it easier to press the column of tissue out of the extractor into the hole at the location of the defect. To facilitate pushing the column of tissue out of the extractor, the surgeon or orthopedic surgeon can also use a small hammer with which he lightly strikes the upper handle part 851 until the upper handle part 851 is in contact with the lower handle part 852, which in turn is on the proximal end face of the handle 83 of the extractor 31.1.

Claims

claims

1. set of instruments for carrying out repairs of endochondral or osteochondral defects (20) by implantation of tissue columns (2) which carry a vital cartilage layer (2 ') on one end face, which set of instruments instruments for creating defined cylindrical openings (21) for the implantation of the tissue columns (2) in the area of the defect (20), instruments for removing tissue columns (2) from vital tissue or for forming tissue columns (2) from an in vitro grown cartilage layer and instruments for implanting the

Has tissue columns (2) in the created cylindrical openings (21), characterized in that the instrument set additionally comprises at least one further instrument group from an instrument group, the instrument group essentially consisting of the following instruments: Instruments for increasing the

Precision with regard to parallelism and positioning of the cylindrical openings (21), instruments for determining an original cartilage surface (22) in the area of the defect, instruments for determining the distance between the base of a cylindrical opening (21) and the original cartilage surface

(22), instruments for removing tissue columns with a predetermined angle (α) between the cartilage surface and column axis and instruments for producing an implant from an in vitro grown cartilage layer (50) for filling the gaps in the cartilage surface repaired with the tissue columns (2).

2. Instrument set according to claim 1, characterized in that the instruments for increasing the precision with regard to parallelism and positioning of the openings (21) are guide instruments (10, 11, 12) for punching or drilling instruments for creating the openings (21), which guide instruments Means for a fixed positioning in the

Have area of a defect to be repaired.

3. Instrument set according to claim 1, characterized in that the instruments for determining the original cartilage surface are a plurality of form gauges (23).

4. Instrument set according to claim 3, characterized in that the

Instruments for determining the distance between the particular cartilage surface (22) and the base of a cylindrical opening (21) have surface templates (24) assigned to the gauges (23) with measuring openings (26) assigned to the openings (21) created.

5. Instrument set according to claim 1 or 3, characterized in that the instruments for removing tissue columns (2) with a predetermined angle (α) between the cartilage surface and column axis at a removal point at the predetermined angle (α) fixable positionable means for guiding

Have removal instruments.

6. Instrument set according to claim 1, characterized in that the instruments for producing an implant from an in vitro grown cartilage layer (50) for filling the gaps between implanted tissue columns (2) as punching instruments (60, 61) or

Cutting instruments are formed.

7. Instrument set according to claim 6, characterized in that the set additionally comprises instruments (70, 72) for measuring the thickness of the cartilage layer (50).

8. Instrument for increasing the precision with regard to parallelism and positioning of cylindrical openings (21) to be created in the region of an endochondral or osteochondral defect (20) for the implantation of tissue columns (2) with a vital cartilage layer (2 '), characterized in that it is designed as a guide instrument (10, 11, 12) for a punching or drilling instrument that can be positioned in the region of the defect (20) and can be fixed.

9. Instrument according to claim 8, characterized in that it has a ring guide (10) and at least one in the ring guide (10) positionable punching or drilling guide (11, 12).

10. Instrument for determining an original cartilage surface (22) in the region of an endochondral or osteochondral defect (20) to be repaired, characterized in that it comprises a plurality of form gauges (23).

11. Instrument for determining the distance between the base of a cylindrical opening (21) created in the region of an endochondral or osteochondral defect (20) and an original one

Cartilage surface (22), characterized in that it has means reproducing the original cartilage surface and a measuring rod.

12. Instrument according to claim 11, characterized in that the means simulating the original cartilage surface (22) are surface templates (24) which have measurement openings (26) correlated with the cylindrical openings (21) created.

13. Instrument according to claim 12, characterized in that the

Surface template (24) can be plugged onto a ring guide (10) which can be fixed in the region of the defect (20).

14. Instrument for removing tissue columns (2) with a predetermined angle (α) between the cartilage surface and column axis for implantation in the region of an endochondral or osteochondral defect (20), characterized in that it can be fixed at a removal point at the angle (α) has positionable means for guiding instruments for removing tissue columns (2).

15. Instrument according to claim 14, characterized in that the

Means for guiding is designed as an essentially tubular extractor guide (30, 30.1) and the removal instrument is designed as an extractor (31, 31.1) that can be inserted into the extractor guide (30, 30.1).

16. Instrument according to claim 15, characterized in that the

Extractor (31.1) has windows.

17. Instrument according to claim 15 or 16, characterized in that the extractor (31.1) is divided by two slots (82) into two extractor parts which are connected by a distal extractor region to a tapered end edge.

18. Instrument according to one of claims 15 to 17, characterized in that the extractor guide (30) has a support flange (32) which forms the predetermined angle (α) with the tube axis.

19. Instrument for producing an implant from an in vitro grown cartilage layer (50) for filling the gaps in a cartilage surface repaired with tissue columns (2), characterized in that the instrument is designed as a punching instrument (60, 61) or as a cutting instrument.

20. Instrument according to claim 19, characterized in that it as

Stamping instrument (60,61) is formed and has a mounting surface (60) in the form of an original cartilage surface (22) and a punching mold (61) with punching blades (62).

21. Instrument for determining the thickness of an in vitro grown cartilage layer (50), characterized in that it is a

Measuring block (70) with indentations (71) of different depths and a weighting block (72).

22. A method for repairing endochondral or osteochondral defects (20) by implantation of tissue columns (2) which have a vital cartilage layer (2 ') on one end face, in cylindrical openings made in the region of the defect, characterized in that for Precise guidance of punching or drilling instruments to create the cylindrical openings (21), a guidance instrument (10, 11, 12) is positioned fixed in the area of the defect.

23. A method for repairing endochondral or osteochondral defects (20) by implanting tissue columns (2), which have a vital cartilage layer (2 ') on one end face, in cylindrical openings (21) made in the region of the defect, characterized that before the repair the original

Cartilage surface (22) is determined, and that this original cartilage surface (22) is reconstructed by the repair.

24. The method according to claim 23, characterized in that the distance between the base of a created cylindrical opening (21) and the original cartilage surface (22) is determined and that the axial length of the tissue column (2) to be implanted in the opening (21) is adapted to this distance.

25. Method for repairing endochondral or osteochondral defects (20) by implantation of tissue columns (2) which have a vital cartilage layer (2 ') on one end face, in cylindrical openings (21) made in the region of the defect, characterized that an angle (α) between a cartilage surface (22) to be created and the axis of a cylindrical opening (21) is determined and that a tissue column (2) to be implanted in the opening (21) has an equal angle (α) between the Has column axis and the cartilage surface and is implanted in a defined rotational position.

26. Method for repairing endochondral or osteochondral defects (20) by implantation of tissue columns (2), which have a vital cartilage layer (2 ') on one end face, in cylindrical openings (21) made in the area of the defect (20). , characterized in that gaps in the cartilage layer between the implanted tissue columns (2) and between the edge of the defect (20) and the implanted tissue columns (2) are filled by a further implant made of an in vitro grown cartilage layer (50).

27. The method according to claim 26, characterized in that the

Cartilage layer (50) for the implantation is punched or cut into a shape or shape with openings for the implanted tissue columns (2).

28. The method according to any one of claims 26 or 27, characterized in that the thickness of those grown in vitro

Cartilage layer (50) is determined and that an opening with a minimal depth is created in the defect area for the further implant made from the cartilage layer, the minimum depth essentially corresponding to the thickness of the cartilage layer grown in vitro.

29. The method according to any one of claims 26 to 28, characterized in that the implant is at least partially backfilled with a filling material (51) from the cartilage layer (50) grown in vitro.