FR2938745A1 - TAP FOR PLACING A CAGE OF A FIXING DEVICE FOR LIGAMENTOPLASTY - Google Patents

Abstract

The subject of the invention is a tap (6) comprising a lower part (600) intended to produce a helical thread (60) in a femoral and / or tibial bone tunnel (T) for setting up a cage (1). ) a fixation device for ligamentoplasty in said tunnel, said tap having a wick (600) having on its outer wall a sharp thread (601), characterized in that the wick (600) is extended downwards by a graduated bulb (630), by counting the graduations (631) of said bulb emerging from said bone tunnel, the surgeon knows precisely the length of the distal segment of said tunnel which is not tapped and which will form the housing of the graft when said cage will be set up.

Description

TAP FOR THE PLACEMENT OF A CAGE OF A FIXING DEVICE FOR LIGAMENTOPLASTY Description Technical Field of the Invention

The present invention relates to a tap for the establishment of a cage of a fixation device for ligamentoplasty.

It concerns the technical field of reconstruction of anterior cruciate ligament of the knee. This technique aims to reconstruct the ligament at its exact anatomical location, using hamstring muscle tendons taken from the patient and placed in the knee joint through small bone tunnels made at the level of the tibia and femur. .

State of the art To perform a ligament transplant, it is common practice to collect the tendons of the internal and semi-tendinous (DI-DT graft type). Suspension strips are frequently used arranged at each end of the ligament graft and intended to be fixed in previously prepared bone tunnels. Fixing the strips and not the graft in the bone tunnels provides high tensile strength and limits the risk of tearing or slipping of the graft. 2938745 -2

The technique of preparation of a graft is well known to those skilled in the art: the surgeon first takes the tendon of the tendon tendon. The ligament loop for a single beam graft is obtained by winding the folded tendon in two around two posts of a conventional preparation bench. This gives a ligament loop with four or five beams. The two ends of the ligament loop are then sutured to close said loop. The suspension strips are then placed at the ends of the ligament loop, outside the transfixing sutures. It is known to use interference screws which are introduced into the bone tunnels in order to hold the suspension strips in position. Such interference screws are for example described in patent document WO 2004/045465 (COLLETTE). These screws, called TLS (Tape Locking Screw) 15 comprise three distinct parts: a proximal portion of cylindrical section, an intermediate portion of conical section and finally a distal portion of cylindrical section whose end is rounded and foam. These screws have a large blunt and non-injurious mesh extending exclusively to the proximal and intermediate portions. This configuration allows these screws to optimally perform their role of tape lock against the wall of the bone tunnel in which a helical thread has been previously prepared by means of a tap. The strips are passed through the bone tunnel by pulling the ligament loop behind them. Once the graft is in place, the screw is inserted in the middle of the two strands of the relay strip and causes its locking by the effect of plating against the bone thread without risk of injuring said strip due to the rounded and foam shape of the net. This technique, however, requires a femoral stump and a tibial box having a larger diameter than the housing of the screw. It therefore appears necessary to make a bone tunnel of several calibers, an operation that can be long and tedious for the surgeon. 2938745 -3

WO 2007/147634 (COLLETTE) discloses the use of a hollow cage to be anchored in the bone tunnel. This fixing device is shown schematically in FIG. 10 of the present application. The hollow cage 1 'has an internal bore opening at each of its ends and an outer wall on which is arranged a thread 10'. The cage 1 'is able to grip and lock the strips B by the effect of a locking member 2' configured to be introduced into the internal bore of said cage. This technique has the advantage of using bone tunnels of a single caliber, the cage 1 'closing off said bone tunnel to delimit the insertion slot 10 of the graft G.

More particularly, the hollow cage 1 'disclosed in WO 2007/147634 has an outer wall provided with a wide 10' cutting thread for screwing and anchoring it securely in the bone tunnel T. The outer wall of the cage terminates at its upper end by a collar 11 'which makes it possible to block its penetration by resting on the cortical bone, at the entrance of the bone tunnel T. As a result, it is not possible to push in the cage 1 'deeply in the bone tunnel T, so that the end of the graft G must penetrate deeply into said tunnel before bearing against the lower end of said cage. As a result, using the fixation device disclosed in WO 2007/147634, the surgeon must prepare a graft having a length greater than that of the graft blocked by TLS screws described in WO 2004/045465 cited above. . Also, it has been found that because of the thickness of the graft, the portion of the strips located just above the ligament loop generally takes the form of a triangle which can not penetrate completely into the interior of the ligament. cage (hereinafter referred triangle strips). FIG. 10 represents a known fixing device of the aforementioned document WO 2007/147634, put in place in a bone tunnel T and blocking the strips B 2938745 -4

of a graft G. With reference to this figure, it can be seen that the graft G is at least spaced a distance D2 'from the lower end of the cage 1'. As a result, by using this fixing device, the end of the graft can not come to be pressed correctly against the lower end of the cage 5 'and therefore at the bottom of its insertion housing, which generates a graft distension with respect to the calculated theoretical tension. Recall that the length of the graft is the sum of the length of the femoral insertion housing, the length between the femoral and tibial apertures and the length of the tibial insertion housing. The object of the invention is to provide a surgical assembly enabling the surgeon to easily and quickly set up the ligamentoplasty fixation device in the tibial and femoral bone tunnels of the patient. Disclosure of the invention. The solution proposed by the invention is a tap having a lower portion 20 for producing a helical thread in a femoral and / or tibial bone tunnel for setting up a cage of a ligamentoplasty fixation device in said tunnel. , said tap having a wick having on its outer wall a sharp thread. This tap is remarkable in that the wick is extended downwards by a graduated bulb. By counting the graduations of the bulb coming out of the bone tunnel, the surgeon knows precisely the length of the distal segment of said tunnel which is not tapped and which will form the housing of the graft when the cage is put in place. DESCRIPTION OF THE FIGURES

Other advantages and characteristics of the invention will appear better on reading the description of a preferred embodiment which follows, with reference to the accompanying drawings, made by way of indicative and non-limiting examples and in which: FIG. 1a is a front view of a hollow cage according to the invention; FIG. 1b is a longitudinal sectional view of the hollow cage shown in FIG. 1c; FIG. 1c is a view from above of FIG. FIG. 2a is a front view of a locking member according to the invention; FIG. FIG. 2c is a view from above of the blocking member shown in FIG. 2a; FIG. 3 is a longitudinal sectional view of a fixing device according to the invention consisting of the hollow cage shown on FIG. Figures la to 1c and the organ blocking device shown in FIGS. 2a to 2c, said device being placed in a bone tunnel and blocking the strips of a graft; FIG. 4a is a front view of a hollow cage according to the invention, in an alternative embodiment, - Figure 4b is a longitudinal sectional view of the hollow cage shown in Figure 4a; - Figure 4c is a top view of the hollow cage shown in Figure 4a; - Figure 5 is a longitudinal sectional view of a fixing device according to the invention consisting of the hollow cage shown in the figures - 5 - 6

4a to 4c and the locking member shown in Figures 2a to 2c, said device being placed in a bone tunnel and blocking the strips of a graft, - Figure 6 is a front view of a tap for making a thread in a bone tunnel for the establishment of the hollow cage, - Figure 7a is a front view of a screwdriver used for the establishment of the hollow cage in a bone tunnel, - the figure 7b is an enlarged bottom view showing the lower end of the screwdriver of FIG. 7a; FIG. 8a is a front view of a screwdriver used for setting up the locking member in the hollow cage; FIG. 8b is an enlarged bottom view showing the lower end of the screwdriver of FIG. 8a; FIGS. 9a to 9f schematize the various steps of the new technique of surgical reconstruction of anterior cruciate ligament of the knee, and in particular schematize the implantation of a graft at the femur. - Figure 10 is a longitudinal sectional view of a fixing device known from the prior art, said device being placed in a bone tunnel and blocking the strips of a graft.

Embodiments of the invention

The fixation device which is the subject of the invention is used for the reconstruction of an anterior cruciate ligament of the damaged knee following a traumatic lesion, by using the tendon of the hamstring muscles taken from the patient and put in place in the joint. knee through small bone tunnels made at the level of the tibia and femur. 2973745 -7

This fixing device comprises a hollow cage 1 into which a locking member is introduced. Referring to Figures 1a to 1c, the hollow cage 1 has a generally cylindrical general shape, with a length of between 10 mm and 25 mm, preferably between 15 mm and 20 mm. The cage 1 has an outer wall on which is arranged a thread 10. According to the invention, the latter is made of foam nets, that is to say non-sharp and non-cutting nets, can not tap alone a bone tunnel. The profile of the thread 10 may be trapezoidal, square, or round. Advantageously, different internal diameters of the threading 10 are provided depending on the type of trauma to be treated, the quality of the patient's bone and its morphology. In practice, cages are used with three series of internal diameters: 8 mm, 9 mm and 10 mm. However, the skilled person may provide other internal diameters depending on the case. The external diameter of the thread 10 varies between 10 mm and 14 mm depending on the dimensions of the internal diameter. The pitch of the thread 10 is between 1.5 mm and 3.5 mm, preferably 2.5 mm.

Referring to Figures 1a and 1b, the outer wall of the cage 1 terminates at the upper end S: 20 - either directly through the thread 10, - or by a smooth portion (shown in dotted lines) having a diameter external less than or equal to the internal diameter of said thread. In this way, only the thread 10 projects on the outer wall of the cage 1, no other element being able to hinder the insertion of said cage into a bone tunnel.

Referring to the embodiment shown in Figs. 1a and 1b, the lower portion of cage 1 may be tapered to facilitate its insertion and insertion into a bone tunnel. This conical portion has a length of between 2 mm and 3 mm and has an outside diameter of about 6 mm at the lower end 1 of the cage 1. The wall 2938745 -8

outer of this conical part is smooth, devoid of threading. Referring to the embodiment shown in Figures 4a and 4b, the lower part of the cage 1 may be cylindrical and terminate directly by the thread 10. Referring to Figures 3 and 10, a conical end 5 is susceptible to penetrate a distance Dl, Dl 'into the femoral and / or tibial insertion housing and thus to reduce by a few millimeters the actual length of the latter, which has the consequence of reducing the tension of said graft once it is placed in the bone tunnel T. On the contrary, referring to Figure 5, a cylindrical end is not likely to penetrate into the insertion housing of the graft.

Referring to Figures lb and 4b, the cage 1 is also provided with an internal bore 11 opening at each end of said cage, respectively at an upper orifice 11s and a lower orifice 11i, 15 both located on the axis of symmetry of said cage (Figure lb). This internal bore 11 is preferably constituted by a threaded cylindrical upper portion 110 and a smooth cylindrical lower portion 111 having a diameter smaller than that of said upper portion. The lower part 111 can be directly connected to the upper part 110 or be connected to the latter by a conical intermediate part 112. The threaded cylindrical upper part 110 has a length of about 7 mm and a diameter of between 7 mm and 9 mm. mm. The cylindrical smooth bottom portion 111 has a length of about 6 mm and a diameter that may be equal to the diameter of the portion 110 or, preferably, less than 6 mm to 5 mm. In the latter case, the conical intermediate portion 112 has a length of about 7 mm, a diameter greater than the diameter of the upper portion 110 and a smaller diameter equal to the diameter of the lower portion 111. The upper portion 110 has a thread 1100 which opens at the upper orifice 11s. This thread extends to a depth of about 6 mm and has a pitch of about 1.5 mm. Any thread profile suitable to those skilled in the art can be used, but it is advantageous to use foamed nets. Referring to Figures 1c and 4c, the internal bore 11 advantageously comprises two longitudinal grooves 113 opening at the upper orifice 11s. These two grooves 113 serve as housing for the strips and / or form cavities for receiving a tool for screwing the cage 1 in the bone tunnel T.

Referring to Figures 2a to 2c, the locking member 2 has a generally conical general shape and could be similar to a screw. The locking member 2 has a length of between 8 mm and 21 mm, preferably 16 mm. It consists of a smooth conical lower portion 211 and a cylindrical upper portion 210 whose outer wall has a thread 2100 configured to collaborate with the thread 1100 made at least in the upper portion 110 of the internal bore 10 of the Cage 1. The smooth tapered lower portion 211 is configured to penetrate into the complementary shaped conical portion 112 provided in the internal bore 11. For a locking member 2 having a total length of about 16 mm, the cylindrical upper portion 210 has a length of about 7 mm for a diameter of about 6 mm and the smooth conical lower portion 211 has a length of about 9 mm. The outer wall of the upper portion 210 has a thread 2100 which extends to the upper end of the locking member 2. This thread has an external diameter of about 7.5 mm, extends over a length about 3 mm and has a pitch of about 1.5 mm. The profile of the thread 2100 corresponds to that of the thread 1100. The threads 1100 and 2100 cooperate so as to hold the locking member 2 in position in the hollow cage 1. This screwing system makes it possible to easily adjust the depth of the thread. depressing the locking member 2 in the internal bore 11. Equivalently, provision could be made to provide the outer wall of the upper portion 210 of the locking member 2, edges perpendicular to the axis of symmetry of said body and parallel to each other. These edges would fit together, without unlocking 2938745 - 10-

possible in housings of complementary shapes made in the upper part 110 of the internal bore 11.

With reference to FIGS. 3 and 5, once the cage 1 is put in place in the previously tapped bone tunnel T, the suspension strips B are passed to the end of the ligament loop of the graft G. then the locking member 2 in the internal bore 11 so as to block the strips B either by wedging between the conical portions 112 and 211, or by wedging between the threads 1100 and 2100. In all cases, when the establishment of the locking member 2 in the inner bore 11, the strips B naturally tend to be housed in the grooves 113 of said bore, which tends to preserve their integrity. It has also been found that the conical lower portion 211 of the locking member 2 makes it possible to press the strips B against the wall of the internal bore 11, while a locking member comprising a cylindrical lower part tends to push back. said strips outside said bore.

Referring to Figures 2b and 2c, the locking member 2 comprises at its upper end, a cavity 213, preferably of oblong shape, for receiving a tool for screwing into the cage 1.

According to a particularly advantageous characteristic of the invention, the locking member 2 has a length less than the length of the internal bore 11 of the cage 1. Referring to FIGS. 3 and 5, when the locking member 2 2 is placed in the cage 1, a housing 114 is formed in the bore 11 delimited by the lower end thereof and the lower end of the locking member 2. Preferably, the lower end the locking member 2 sinks into the internal bore 11 over a length at most equal to 3/4 of the length of said bore, that is to say that the length of the housing 114 is at least equal to to 1/4 of the length of the internal bore 11. However, quite acceptable results are obtained with a length 2938745 -11-

less. By comparing FIG. 3 with FIG. 10, with the invention, the triangle of the strips B is able to penetrate in the housing 114, so that the end of the graft G can be pressed closer to the lower end. of the cage 1. It can therefore be seen that with the device according to the invention, the graft G is spaced from the lower end of the cage 1 by a distance D2 smaller than the distance D2 'obtained with a device similar attachment known from the prior art.

With reference to FIGS. 4b and 5, the orifice Ili at the lower end I of the cage 1 can be chamfered on the side of the internal bore 11, over a length at least equal to 1/8 of the length of said bore. In this way, the triangle of the strips B is able to penetrate integrally into the housing 114, so that the end of the graft G can directly come to press against the lower end of the cage 1, or even slightly penetrate the housing. The chamfer can be straight but is advantageously rounded in order to better preserve the integrity of the strips B during tightening.

The hollow cage 1 and the blocking member 2 may be made of titanium 20 or advantageously of composite or bioabsorbable materials of the PLA (Poly-Lactic-Acid) type combined with an osteoinductive substance of the TCP type (Tri-Calcium -Phosphate). However, it is preferred to make these two elements polyaryletherketone (or PEEK).

The new method of surgical reconstruction of anterior cruciate ligament of the knee using the device object of the invention will now be described in more detail with reference to FIGS. 9a to 9f. This method is very simple to execute. The semitendinosus is first drawn by a small approach to the upper surface of the leg with a stripper. In a manner well known to those skilled in the art, this half-tendinous is put in traction by plication on 2938745 -12-

himself in 4 or 5 strands. The traction is done on a table which is manually adjusted, then leave in place the time of the arthroscopic surgery, about 10 min to 50 Kg. The future femoral orifice is prepared in a manner well known to the man of the trade with a viewfinder making it possible to make an orifice from outside to inside with a pin 5 of 2.5 mm. On this spindle 5 is lowered a 8 mm, 9 mm or 10 mm ginnerick, the last diameter being fixed by the diameter of the completed graft on the table: it can be 8 mm, 9 mm or 10 mm. Once femoral tunnel T is made, pin 5 remains planted in the opposite condyle (Figure 9a). The tibial tunnel is made in a similar way. The femoral tunnel T is lowered into a tap 6 configured to produce a helical thread 60 on the wall of said tunnel (FIG. 9b). This tap 6 is shown in more detail in FIG. 6. It comprises in its lower part a wick 600 in the form of a cylindrical body approximately 20 mm long and having on its outer wall a sharpened net 601. , with a pitch of 2.5 mm. This wick 600 makes it possible to produce the helical thread 60 on the wall of the bone tunnel T. The thread 601 has an external diameter of approximately 12 mm and an internal diameter of 8 mm, 9 mm or 10 mm according to the diameter of the bone tunnel previously realized. This wick 600 is extended upwards by a cylindrical rod 610 whose end is provided with an operating handle 620. The cylindrical rod has a length of about 60 mm and a diameter of about 8.5 mm. The wick 600 is extended downwards by a metal bulb 630 of about 25 mm long. This bulb 630 has on its outer wall circular graduations 631. The bulb 630 is advantageously graduated 0.5 mm in 0.5 mm although another graduation can be considered. In practice, the diameter of the bulb 630 is at most equal to the internal diameter of the thread 601. These graduations stop the tapping accurately in the bone tunnel T. Indeed, as soon as the bulb 630 out of the bone tunnel T, and by counting the graduations 631, the surgeon knows precisely the length of the distal segment of the tunnel which is not tapped and which will form the housing of the graft when the cage 1 will be put in place (Figure 9c). This distal segment no 2938745 -13-

For example, the tapped thread has a length of about 10 mm for the femur and about 20 mm for the tibia. The tap 6 is advantageously provided with an internal cylindrical bore 640 opening at each of its ends. This bore is configured to allow the passage of the guide pin 5 which imposes its direction. In the same way, the tap 6 is introduced into the tibia tunnel from outside to inside and also slides on a guide pin. The hollow cage 1 is then put in place in the tapped bone tunnel (FIG. 9d), said cage transforming the unthreaded distal segment into a blind hole which corresponds to the housing of the graft G. Because the cage 1 10 comprises threads foams, it can not go beyond the threaded portion 60 which ensures a very precise positioning. The cage 1 is put in place by means of a specific screwdriver 7 shown in detail in FIGS. 7a and 7b. This screwdriver 7 has a cylindrical rod 710 fixed to a handle 720. The cylindrical rod has a length of about 120 mm and a diameter of about 8 mm. The handle 720 has a length of about 100 mm and a diameter of about 20 mm. The rod 710 enters the handle 720 over a length of about 30 mm. Referring to Figure 7b, the end of the rod 710 ends with a tip 730 whose section corresponds to that of the upper part of the hollow cage 1. In particular, the section of the tip 730 20 comprises two 7310 extensions adapted to fit into the longitudinal grooves 113 of the cage 1. This screwdriver 7 is also advantageously provided with an internal cylindrical bore 740 opening at each of its ends, this bore being configured to allow the passage of the spindle guide 5 which imposes its direction. A similar hollow cage is set up in the same way in the tibial tunnel. The strips B connected to the graft G are introduced into the cage 1, from the outside to the inside of the knee, and retrieved in a conventional manner first at the level of the external femoral channel (FIG. 9e) and then at the level of the tibial path. Other introduction techniques may, however, be carried out by the surgeon. In a manner known to those skilled in the art, the strips B are attracted into the cage 1 and the bone tunnel by means of a wire 2938745 - 14 -

traction lasso-shaped. The strips B are then discarded once the end of the graft G is abutted against the cage 1. First at the femoral level, the locking member 2 is introduced into the cage 1 (Figure 9e) by means of a specific screwdriver 8 shown in detail in FIGS. 8a and 8b. This screwdriver 8 comprises a cylindrical rod 810 attached to an operating handle 820. The cylindrical rod 810 has a length of about 100 mm and a diameter of about 5 mm. The handle 820 has a length of about 100 mm and a diameter of about 16 mm. Referring to Figure 8b, the end of the rod 810 terminates in a tip 830 whose section corresponds to that of the cavity 213 made at the upper end of the locking member 2. Once the locking member 2 is correctly placed in the cage 1 and the strips B are locked, said strips are cut or knotted. At the tibial level, the process of setting up the locking device is exactly the same. To implement this method, the surgeon will preferably have a surgical assembly comprising: - a fixing device according to the invention (hollow cage + locking member), 20 - the tap 6 and possibly the screwdrivers 7 and 8 previously described.

This surgical assembly may further include; threads connected to a single-ended curved needle intended to suture between them the ligamentous bundles of the tendon graft so as to form one or more ligament loops, suspension strips, traction threads intended to attract the strips suspension through hollow cages and femoral and tibial bone tunnels.

This surgical assembly can be in the form of a sterile case obtained by plastic molding and closed by a protective envelope 2938745 -15-

detachable adhesive. Different compartments may be provided to house individually each component of the surgical assembly.

Claims (6)

Revendications1. Tapping (6) having a lower portion (600) for producing a helical thread (60) in a femoral and / or tibial bone tunnel (T) for positioning a cage (1) of a fixation device for ligamentoplasty in said tunnel, said tap comprising a wick (600) having on its outer wall a sharpened thread (601), characterized in that the wick (600) is extended downwards by a graduated bulb (630), by counting the graduations (631) of said bulb exiting said bone tunnel, the surgeon knows precisely the length of the distal segment of said tunnel which is not threaded and which will form the housing of the graft when said cage will be put in place. The tap of claim 1, wherein the graduated bulb (630) has a length of about 25 mm. 3. Tapping according to one of the preceding claims, wherein the graduated bulb (630) has on its outer wall circular graduations (631), said bulb being graduated 0.5 mm in 0.5 mm. 4. Tap according to one of the preceding claims, wherein the diameter of the bulb (630) is at most equal to the internal diameter of the thread (601). 5. Tap according to one of the preceding claims, wherein the wick (600) is extended upwardly by a cylindrical rod (610) whose end is provided with an operating handle (620). 2938745 -17- 6. Tap according to one of the preceding claims, comprising an internal cylindrical bore (640) opening at each of its ends.