EP0498874A1

EP0498874A1 - Artificial ligament for reinforcing the rotulian tendon

Info

Publication number: EP0498874A1
Application number: EP91916269A
Authority: EP
Inventors: Pierre-Louis Peyrou; Georges Comte
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-08-30
Filing date: 1991-08-30
Publication date: 1992-08-19
Also published as: WO1992003988A1; CA2072113A1; AU8528591A; FR2666219B1; FR2666219A1

Abstract

La présente invention concerne un ligament prothétique (7) pour le renforcement du tendon rotulien (3) verticalisé par retournement des fibres externes (5) dudit tendon (3). Les fibres longitudinales (13) constituant l'âme du ligament artificiel (7), sont en position d'extension permanente maximum, totalement rectilignes et parallèles entre elles, unies en extension par un tricotage en chaîne, non déformant suivant un réseau de mailles (14). Le ligament (7) présente en ses deux extrémités (18) un aplatissement des fibres longitudinales (13), normalement obtenu par une couture transversale (17).The present invention relates to a prosthetic ligament (7) for strengthening the patellar tendon (3) verticalized by inversion of the external fibers (5) of said tendon (3). The longitudinal fibers (13) constituting the core of the artificial ligament (7), are in the position of maximum permanent extension, completely rectilinear and parallel to each other, united in extension by a warp knitting, non-deforming according to a network of stitches ( 14). The ligament (7) has at its two ends (18) a flattening of the longitudinal fibers (13), normally obtained by a transverse seam (17).

Description

ARTIFICIAL LIGAMENT FOR THE RENDERING OF THE TENDON

ROTULIEK

The present invention relates to a prosthetic ligament intended for the strengthening of the patellar tendon having undergone partial disinsertion of its external part within the framework of a treatment of the syndrome of hyperpressure of the patella.

We know that the external hyperpressure syndrome of the kneecap is today considered as one of the most frequent pathologies of the knee, mainly affecting adolescents and young adults; it is the consequence of an anomaly in the position of the patella, not in a frontal plane in which the patella remains strictly centered with respect to the trochlee on the fa oropatellar incidences, but in a transverse plane. During the contraction of the quadriceps, the kneecap of the affected knee performs an external rotation tilt which abnormally exacerbates the stresses of the external femoro-patellar compartment at the expense of the internal compartment, thus creating often unbearable pain; moreover, when this phenomenon is prolonged for years, it can lead to a degradation of the outer cartilaginous femoro-patellar covering.

Usually, the treatment of this external overpressure of the patella consists of a simple ablation of the external patellar fin, so as to reduce the hyperpressure whereas the usual retraction of said external patellar fin is in fact only the consequence of the rotational anomaly of the patella and the positive effects of partial ablation of the aileron are generally quite temporary.

Another treatment for overpressure of the patella consists of a simple translation of the tibial tuberosity, so as to substantially align the patellar tendon; it is well known that, in this case, such a c rection results in increasing the internal femoral stresses. Indeed, the tilt of the patella and the patellar hyperpressure which is the consequence of it are due to traction at the bottom and outside of the patella during the quadricipital contraction due to the position of the outermost fibers of the patellar tendon. These same fibers are inserted at the external part of the tibial tuberosity forming an open angle, outside, with the vast external muscle causing the patella to tilt during the quadricipital contraction with the harmful consequence of dragging it outside. Another treatment consists of a suitable rehabilitation aimed at strengthening the low fibers of the vast internal. This treatment is unfortunately long and very uncertain.

A new treatment has therefore been proposed for the syndrome of external hyperpressure of the patella prescribing the inversion inward of the external fibers of the patellar tendon, providing a triple effect: a) the inversion erases the angle opened outside by verticalizing the tendon with the consequence of suppressing the component of external dislocation during quadricipital contraction. b) the inversion gives the kneecap a slight internal rocking movement during the contraction of the quadriceps. c) the inversion finally leads to an advance of 0.7 to 0.9 millimeters of the average insertion of the patellar tendon, thus creating a "Maquet effect" tending to reduce the overall patellar stresses.

It is clearly understood, however, that under these conditions, the disinsertion of the external fibers of the patellar tendon, with a view to their reversal, creates a certain weakening of said patellar tendon, all the more so as it is recommended in practice to dissect the external third of the tendon normally inserted at the external part of the anterior tibial tuberosity. In this regard, a test intervention was carried out on 98 patients who were operated by this technique of transposition, inversion, verticalization of the patellar tendon, and we were able to note 89% of total success; however, it was noted in the immediate aftermath:

- 12 times of delayed support beyond the fourth week due to pain when inserting the patellar tendon.

- 5 persistent tendonitis due to excess traction on the remaining patellar tendon. This is why it is proposed, according to the invention, to counterbalance the weakening of the patellar tendon resulting from the disinsertion of its external part by strengthening the internal two thirds of said tendon and this, by means of an adequate prosthetic ligament inserted between the inverted fibers and the internal fibers of the same tendon. To this end, a homogeneous, unsheathed, non-woven and non-braided ligament has been researched and developed according to the invention, characterized in that the longitudinal fibers are held transversely together by knitting in a non-deforming warp, 'said longitudinal fibers at the outset in a position of maximum extension, while remaining completely rectilinear and parallel, since they are not deformed by the undulations of a weaving or braiding for example; the ligament thus obtained by winding in successive concentric turns of such a knitted fabric of longitudinal artificial fibers, is then made up of three distinct parts: a) an average part of cylindrical section which will be inserted into the patellar tendon during its derotation. This tubular part of the prosthetic ligament according to the invention extends approximately three centimeters long for a diameter of approximately four millimeters. b) a flattened lower part consisting of the extension of the fibers into a strip approximately 0.7 millimeters wide. This flattened part is intended to be inserted on the internal face of the tibia by means of a serrated staple without any relief. c) a proximal part also flattened like the lower part, coming to end on the juxtarotulary part of the patellar tendon. The proximal part is then sutured at this level by normally absorbable threads, providing no annoying protrusion at the lower part of the patella.

Advantageously, the two end parts of the prosthetic ligament according to the invention are obtained by means of a simple seam made transversely at the two ends of the middle and cylindrical part intended to be inserted inside the patellar tendon.

Another important characteristic of the reinforcing ligament according to the invention is that the knitting used for the manufacture of said ligament is of the non-flammable type, promoting rehabitation of said ligament by connective tissue resulting in better solidification of the tendon in the vertical axis chosen. . This technique of ligamento-plasty by inversion with burial of an artificial ligament of reinforcement, has very many advantages:

- absence of post-operative immobilization taking into account the immediate solidity of the artificial ligament of reinforcement (this ligament can resist traction close to 1800 newtons), - absence of post-operative tendinitis, contrary to what had been observed during the treatment by inversion without the use of an artificial ligament of reinforcement,

- absence of any risk of tibial disinsertion of the remaining two thirds of the fibers constituting the patellar tendon,

- absence of excessive traction on the external third of the transposed fibers of the patellar tendon, since the latter is securely sutured on the reinforcing ligament,

- absence of subcutaneous tibial protrusion in the supero-internal part of the leg, where there is no musculo-aponeurotic training to cover the inverted tendon,

- easy insertion of the cylindrical middle part of the reinforcing ligament in the tunnel formed by the inverted patellar tendon,

- easy insertion of the extreme parts of the reinforcing ligament in the immediate vicinity of the patella of the tendon, without the appearance of an unsightly and embarrassing external projection for the patient. All these advantages will emerge more clearly from the description which will be given of the prosthetic reinforcing ligament according to the invention, within the framework of a ligament-plasty, given below by way of preferred and nonlimiting example with reference to the drawings. , wherein :

- Figure 1 shows a schematic view of the patella assembly in place on the knee joint in a position leading to patellar hyperpressure syndrome, insofar as the axis of traction of the quadriceps and the angle of resistance of the patellar tendon form an open angle behind and outside, according to the force diagram shown in the figure.

- Figure 2 shows a schematic view of the patella assembly in place on the knee joint, showing in a partial enlarged view, the inversion and suturing of the external third of the patellar tendon turned inside out (arrow T), after incision of the external third of said patellar tendon at its tibial insertion, and showing, after reversal of the external third of the patellar tendon, the erasure of the external hyperpressure component with the consequence that the patella no longer tends to tilt on itself during a quadricipital contraction (it will be observed that the centering of said patella is however not modified).

- Figure 3 is a schematic view similar to the previous one, in which there is shown the insertion of an artificial ligament of reinforcement enveloped by the reversal of the external third disinserted and fixed to the tibia by a serrated staple.

- Figures 4a and 4b show schematically, in front view 4a and in side view 4b, the type of stitches constituting the weft of the knit holding transversely the longitudinal fibers forming the reinforcing ligament according to the invention.

- Figure 5 shows the artificial reinforcing ligament according to the invention, in a top view in light perspective.

In accordance with Figures 1 to 3, the patellar assembly is shown in position on the knee joint in order to better highlight the technique of verticalization of the patellar tendon, essential, as we have seen, for the definitive treatment of the patellar hyperpressure syndrome; in FIG. 1, the quadrilateral of the forces exerted on the patella 1 is represented, composed by the tensile force FI of the quadriceps 2 and of the reaction of the patellar tendon 3, since these forces are not strictly in opposition, this which is seen in patellar hyperpressure syndrome; this hyperpressure is all the more important as the resultant R of the forces FI and F2 is large. In accordance with the treatment recommended under the invention, the verticalization of the patellar tendon 3 is obtained by a simple partial disinsertion of said patellar tendon 3 which is carried out by a simple external parapatellar incision extending to the anterior tibial tuberosity 4 over six centimeters about.

Initially, a careful dissection of the external third of the patellar tendon 3 is performed, which is normally inserted into the external part of the anterior tibial tuberosity 4.

The external fibers 5 of the patellar tendon 3 are then turned over according to the arrows T (FIG. 2) to be reinserted into the internal part 6 of said tendon 3 without any traction to avoid a risk of lowering of the ball joint 1. It will also be noted that during a ligament-plasty without an artificial reinforcing ligament, a suture of the external third of the fibers of the patellar tendon 3 is turned inside out. Under these conditions and in accordance with FIG. 2, a total verticalization of said tendon 3 is then obtained, the forces FI and F2 having directions totally aligned, so that the resultant R responsible for the external hyperpressure is canceled, consequently avoiding the corresponding syndrome. It will be observed that under these conditions, the ball joint 1 no longer tends to tilt on itself during the quadricipital contraction and its centering has, moreover, not been modified in the operation. However, all the drawbacks of such a reversal treatment are known, insofar as the disinsertion of the external third of the patellar tendon 3 generally results in an intolerable weakening of said tendon 3, which must therefore be compensated for. We have already seen that such compensation can be advantageously obtained by the use of a specific artificial ligament 7 which is included in the patellar tendon 3 during the derotation of the outer third of its fibers, in accordance with the diagram shown on Figure 3. Said artificial ligament 7 is held firmly in the tibia 8 by means of a serrated clip 9, simultaneously encasing the reinforcing ligament 7 and part of the base of the patellar tendon 3, just above its area of tibial insertion 10. It will be noted that the use of a serrated staple is particularly advantageous, insofar as it brings no projection to the subcutaneous relief of the upper-internal part of the leg, whereas the it is well known that there is no musculo-aponeurotic training enabling the inverted tendon to be covered.

The proximal part of the reinforcing ligament 7 having a characteristic shape as will be said below, comes to be flush with the juxtarotular part 11 of the patellar tendon 3, to which it is then sutured by simple absorbable wires 12 thus making no annoying protrusion at the lower part of the patella 1.

It should be noted that the mechanical strength of the ligament 7 is finally achieved by the combined action of the staple 9 fixing the tibial end, of the juxtarotular suture for the other end, putting the ligament in extension, and by an overlock produced between the transposed edge of the patellar tendon 3 and the middle part of the ligament 7 providing said patellar tendon 3 with immediate reinforcement while awaiting rehabitation by the body.

In this regard, the fibers of the reinforcing ligament 7 are made of biologically rehabitable polyester; thus, in a few months, a perfectly vertical neo-tendon is formed, maintaining the ball joint 1 in the frontal plane during contractions of the quadriceps 2.

With reference to FIGS. 4 and 5, a detailed description will now be given of the reinforcing ligament 7 used in the treatment of the syndrome of hyperpressure of the patella.

The general structure of the reinforcing ligament 7 is obtained from polyester fibers, for example a polyethylene terephthalate, the biocompatibility of which has been well known for a long time. The choice of this material results from the fact that the fiber which, with equal resistance, has exhibited the best hysteresis, that is to say the minimum residual elongation after tensile cycles of increasing force. The reinforcing ligament 7 according to the invention is unsheathed, non-woven, non-braided and its originality lies in the fact that it is a set knitted in such a way that all of the longitudinal fibers 13 (FIGS. 4) constitute the core of the ligament 7 are immediately in their maximum extension position, completely rectilinear and parallel (FIG _. 4a _. ) and that said longitudinal fibers 13 are placed in optimal conditions for working simultaneously. These same fibers 13 called "weft" are not deformed by the undulations of a weaving or of a braiding but, on the contrary, are united in permanent extension by knitting in a non-deforming warp chain, according to a network of stitches 14 of which a preferred example, although not limiting, is given in FIGS. 4. a nonwoven knitting also making it possible to obtain a high porosity, of the order of 400 microns, very favorable to rehabitation by the body which reconstitutes in a few months a patellar neo-tendon. The knitting of straight and parallel fibers 13 obtained as mentioned above, is then wound on itself, along a longitudinal axis parallel to the fibers 13, in successive and concentric passes 15, so as to form a tube, comprising a quarantine fibers 13 of polyethylene terephthalate, with a diameter substantially equal to four millimeters over a total length of approximately twenty centimeters.

As we have seen previously, the reinforcing ligament 7 according to the invention comprises three parts, each corresponding to a precise mechanical function in the strengthening of the patellar tendon 3.

According to Figure 5, the reinforcing ligament 7 consists of a substantially tubular central portion 16 corresponding to the original winding. This central part 16 of the ligament is three centimeters long and corresponds to the area of the ligament 7 which will be inserted between the external part 5 of the inverted patellar tendon 3 and the internal part 6 of said tendon which remains in place, forming a substantially cylindrical cavity as said central part 16 comes exactly to occupy.

The central tubular zone 16 of the ligament 7 is delimited by seams 17 made in the transverse direction creating a crushing on either side of said central zone 16, from which extend the two ends 18 of the reinforcing ligament 7 according to The invention. Each reinforcing end 18 7 formed by the extension of the fibers 13 is then flattened along a strip of ten centimeters in length and a width of about 0.7 millimeters by any means known to those skilled in the art. Art. We know that one of them is intended to be inserted on the internal face of the tibia 8 by means of a serrated clip 9 providing the lower stowage of the reinforcing ligament 7 according to a quite known technique, so that the other part will be transferred to the fixation of the reinforcing ligament 7 on the juxtarotular part of the patellar tendon 3 to which it is sutured by absorbable wires 12 (FIG. 3).

It is obvious that the seams produced at the two ends of the central part 16 of the reinforcing ligament 7 are in principle carried out manually, but there is nothing to prevent this operation from being mechanically stitched or crushing by any other equivalent technical means, with or without seam, moreover. Likewise, the choice of polyethylene terephthalate cannot be considered as the only material suitable for the production of the reinforcing ligament according to the invention, which could, with a few adaptations within the reach of a person skilled in the art, be replaced by any other artificial fiber.

Claims

1 - Prosthetic ligament (7) for strengthening the patellar tendon (3) verticalized by inversion of the external fibers (5) of said tendon (3), characterized in that on the one hand the longitudinal fibers (13) constituting the core of the artificial ligament (7), are in a position of maximum permanent extension, totally rectilinear and parallel to each other, united in extension by a warp knitting, non-deforming along a network of stitches (14) and in that, on the other hand, said ligament (7) has at its two ends (18) a flattening of the longitudinal fibers (13), normally obtained by a transverse seam (17). 2 - Prosthetic ligament according to claim 1, characterized in that the longitudinal fibers (13) are held together by a nonwoven knitting.

3 - Prosthetic ligament according to any one of claims 1 or 2, characterized in that the core of the ligament (7) is obtained by winding on itself, in successive and concentric passes (15), along a parallel longitudinal axis to the fibers (13), a knitted fabric of fibers (13) straight and parallel.

4 - Prosthetic ligament according to claim 3, characterized in that the core of the ligament (7) comprises around forty longitudinal fibers (13) so that the diameter of the cross section of the central zone (16) is cylindrical around 4 mm.

5 - Prosthetic ligament according to any one of the preceding claims, characterized in that the central zone (16) of the ligament (7) extends over a length substantially equal to 3 centimeters.

6 - Prosthetic ligament according to any one of the preceding claims, characterized in that the width of the terminal zones (18) is substantially equal to 0.7 mm.

7 - Prosthetic ligament according to any one of the preceding claims, characterized in that the fibers of the ligament (7) are made of polyethylene terephthalate.