Patent Publication Number: US-2023157685-A1

Title: Device and assembly for repairing soft tissues, for example tendons and ligaments

Description:
SUMMARY OF INVENTION 
     The subject matter of this invention is a bio-compatible and bio-resorbable implantable device for repairing soft tissues. 
     In particular, the implantable device is suitable for repairing soft tissues subjected to tensile loads under physiological conditions. The implantable device is particularly suitable, although not uniquely intended, for tendon repair. The device may be used in the field of ligament injuries. 
     This invention also relates to an assembly comprising said bio-compatible and bio-resorbable implantable device and a non-implantable element for perforating the soft tissue. 
     PRIOR ART 
     Tendons are made up of very strong, poorly elastic fibrous tissue, the function of which is to transmit the contractile action exerted by a muscle to the corresponding skeletal segment. Other types of soft tissue subjected to tensile loads are formed of ligaments. 
     Fibrous tendon tissue is mainly made up of type I collagen chains helically wound to form a set of fibers aligned in the transmission direction of the load. 
     Tendons may be injured in various ways: direct trauma (cuts, crushing, lacerations, etc.) or indirect trauma (violent muscle contractions, sudden flexion or counter-resistance of a joint, etc.); athletes and dancers in particular are exposed to indirect trauma and the tendons most frequently involved are the Achilles tendon, the patellar-femoral tendon, the biceps, and the flexors of the fingers. Tendons may also deteriorate as a result of excessive fatigue, as may occur in the case of dancers, in degenerative diseases or the like, and/or related causes. Some additional areas of particular interest are: the hand flexors, foot flexors, tibialis anterior, patellar tendon, and the tendons of the quadriceps, biceps, and rotator cuff. 
     In most cases, the tendon must be surgically repaired to heal; the procedure involves making an incision in the skin, isolating and bringing the tendon stumps together and keeping them in contact until the tendon is completely healed; healing occurs through the formation of scar tissue, which is less resistant, and “neo-tendon” tissue, i.e., that which is functionally and histologically similar to the healthy tendon. The relationship between the two regenerated tissues is directly linked to the type of surgical repair and to the rehabilitation methods. 
     Surgical suturing (thread and needle) with resorbable or non-resorbable material is currently the most used system to repair tendon injuries; it has a low cost, is easily available, does not require dedicated tools for its application, and currently has a more favorable cost-benefit index than the other treatments on the healthcare market. However, surgical suturing has a number of drawbacks: it promotes the formation of scar tissue both inside and outside the tendon resulting in lower resistance to tensile forces of the repaired tissue and increased resistance to the sliding of the tendon and to the development of the joint movement; the locking point of the thread (knot) is the main area of weakness to tensile forces of the system with re-ruptures of the tendon possible; both the thread and the knot determine, at the point of repair, an increase in the size of the tendon in a measure directly proportional to the increase in the caliber of the thread required, with potential repercussions on the tissues adjacent thereto, without thereby leading to an improvement in the mechanical properties of the tendon. 
     The various suturing techniques may require a super-specialized preparation because they are not easy to perform. The suture does not ensure a sufficient grip for active joint mobilization and, depending on the tendons, passive mobilization for three or four weeks, with a resulting delay in physiotherapy and increased complications such as pain, joint stiffness, failure to recover movement, need for follow up surgery. For these reasons, patients who suffer a tendon lesion are forced into a long period of disability, require prolonged physiotherapy, and in no small percentage of cases do not fully recover the functionality of the affected area. 
     Naturally, even in the case of animals, especially competition animals, such as for example horses, the aforementioned problems are encountered mutatis mutandis. 
     The need is therefore strongly felt to provide an improved solution with respect to conventional surgical sutures for the treatment of traumatic injuries of the tendons. 
     In place of traditional surgical sutures, systems have been proposed that use staples, rivets, pins, or other metal retaining elements, which obviously do not solve the problems described above with reference to sutures, especially with regard to the invasiveness of the inserted device, the potential to cause inflammation and infection, and a non-optimal distribution of stresses, being in the best of cases only simpler for an operator, for example a surgeon, to apply. 
     For example, U.S. Patent Application No. US-2015-0173737 discloses a solution for repairing an injured tendon consisting of an elongated element intended to be inserted inside both stumps of the tendon to be repaired to act substantially as a retaining element between the two stumps. Sutures or other fastening systems of the elongated element allow it to be fastened to the tendon stumps, which otherwise would tend to move away in the event of muscle contractions in that area. This solution is therefore very invasive and requires making a longitudinal cavity to insert the elongated element inside the body of the two tendon stumps to be brought together, which then must be sutured or riveted to the tendon, causing further permanent inflammation. The application procedure is also complex and entails a risk of injury for the surgeon. 
     For example, U.S. Patent Application No. US-2003-0065360 shows a bandage intended to be wrapped around a tendon and provided with sharp clamping barbs designed to be individually anchored to the tissue to be repaired to secure the bandage to the tissue, substantially acting as a clamping band. This solution, if applied to tendon repairs, would not be without drawbacks. For example, the tips of the clamping barbs of the bandage would act as needles resulting in a source of further localized, as well as distributed, inflammation, due to the large number of such clamping barbs, in the tissue of the tendon to be repaired. Or worse, in the event that such needles or barbs infiltrate between the longitudinal fibers of the tendon to be repaired, the clamping could even fail. The sharp barbs are further arranged in parallel rows, i.e., along the same tendon fiber, and, during muscle contraction and tensioning of the cuffed tendon, this would likely cause mechanical stress focused on a small number of fibers, easily causing the fraying and/or the longitudinal separation of the tendon fibers, as well as the removal of said sharp barbs. 
     For example, U.S. Patent Application No. US-2018-0168798 in the name of CABLE FIX shows a solution formed by a pair of rigid metal plates linked together with a wire or cable that tends to urge the two plates towards each other through the body of the tissue to be repaired. Spacer elements extend through the body of the tissue latching the two plates together and are provided with relevant sliding grooves for the plates having abutment surfaces which limit the approach between the two plates by keeping them at a certain distance. Sharp perforating needles are provided on one of the two plates to penetrate the tendon tissue. This solution does not solve the aforementioned problems relating to sutures due to the provision of said prestressed cables. The prestress exerted by these cables constantly presses to compression the cross section of the tissue between the plates. In addition, the sharp needles are a source of further inflammation and damage to the tissue to be repaired. 
     For example, Italian patent application No. IT-2018-000006092 in the name of the same Applicant shows a clamping band solution to be wrapped around a tendon provided with barbs for anchoring to the tendon stumps to be repaired. This solution, although advantageous from some points of view and in particular due to its intrinsic compatibility with biological tissues, is not suitable for satisfactorily stimulating the regeneration of the native fibrous tissue of the tendon, imposing long healing times, which are often incompatible with the contingent professional needs of athletes and dancers. 
     The need is therefore strongly felt to provide a solution to repair a soft tissue, for example a tendon or a ligament, which is of reduced invasiveness with respect to known solutions, easy to apply through surgery, and at the same time suitable for allowing a rapid and complete recovery of the functionality of the tissue while also ensuring the mechanical resistance necessary for the entire duration of the rehabilitation phase. 
     The need is also felt to provide a solution to repair damaged soft tissue, for example a tendon or a ligament, in a shorter time, without being more invasive or even worse, resulting in an unsatisfactory functional recovery of the tissue. 
     The need is felt for a solution which is definitive and therefore avoids a second surgical intervention for its extraction and which does not damage the soft tissue over long periods if it remains in place. 
     SOLUTION 
     One object of this invention is to remedy the drawbacks of the prior art heretofore attested with reference to the state of the art. 
     A particular object of this invention is to devise a bio-compatible and bio-resorbable device, minimally invasive and suitable for allowing a rapid and complete healing of the soft tissue, such as for example a damaged tendon. 
     This and other objects are achieved with a device according to claim  1 , as well as with an assembly according to claim  11 . 
     Some advantageous embodiments are the subject of the dependent claims. 
     According to an aspect of the invention, a bio-compatible and bio-resorbable implantable device for repairing a soft tissue, for example a tendon, comprises at least two plates that may be interlocked by means of a plurality of connecting elements which act as elements for positioning the plates with respect to each other and with respect to the tissue to be repaired. The at least two plates and the connecting elements are all bio-compatible and bio-resorbable. The connecting elements extend from one plate to the other plate with the purpose of locking said first plate and said second plate in a definable respective position, avoiding the need for suture threads. 
     According to an aspect of the invention, an assembly comprises at least one bio-compatible and bio-resorbable implantable device and a non-implantable perforating device made as a separate piece from said bio-compatible and bio-resorbable implantable device, wherein said perforating device comprises a plurality of perforating elements suitable for making perforations, preferably through perforations, in said soft tissue to form positioning paths for said plurality of connecting elements of the bio-compatible and bio-resorbable implantable device. The perforating device may be made in the form of another non-implantable plate. 
     The implantable device may also provide a possible functional coating with growth factors or with drugs that promote and speed up the process of forming autologous tissue, thus decreasing the risk of excessive scar tissue formation. These substances do not necessarily have to be in the form of a coating, but rather may be contained or encapsulated within nanoparticles, which may be inserted or incorporated within the same material and therefore distributed over the entire volume of the implantable device. 
     The connecting elements comprise a first portion integral with the first plate and a second portion integral with the second plate. For example, a first connecting element portion is formed by a pin and the second connecting element portion is formed by a rim of a hole. 
     The connecting elements may be of equal shape and size to each other, as well as made of the same material composition. 
     The interlocking of two portions of a connecting element and in this way of the plates to each other may take place by means of undercut coupling. 
     The tips of the pins or protrusions of the connecting elements may be rounded to avoid injuring the tissue to be repaired. The lateral surface of the connecting elements may be rounded. 
     The perforating elements may each define a longitudinal through channel to allow the insertion of the connecting elements of the bio-compatible and bio-resorbable implantable device, whereby the perforating elements are fitted on the first portion or on the second portion of the connecting elements during implantation of said first plate or of said second plate, respectively. 
     The connecting elements may each define a longitudinal through channel for inserting the perforating elements of the perforating device, whereby the connecting elements are fitted onto the perforating elements during the implantation of at least one of said first plate or said second plate. 
     The perforating elements may be made in separate pieces with respect to the support of the perforating device and fastened thereto, for example by means of threaded fastening means. 
     By virtue of the proposed solutions, a bio-compatible and bio-resorbable implantable device is provided, suitable to act as an element for transmitting the tensile load to injured soft tissue, for example a tendon, thus avoiding tensile stress on the length of soft tissue in the healing phase. 
     By virtue of the proposed solutions, it is possible to uniformly distribute the tensile load in the cross section of the soft tissue, for example a tendon, during the autologous tissue regeneration or self-repair phase. 
     The bio-compatibility of the material of the implantable device allows for unfavorable interactions between said material of the implantable device and the surrounding tissues to be avoided, ensuring the formation of autologous tissue and self-repair, without inducing the excessive formation of scar tissue and inflammatory processes related thereto. 
     By virtue of the proposed solutions, a non-implantable perforating device is provided, suitable to guide the minimally invasive insertion of the bio-compatible and bio-resorbable implantable device into the soft tissue to be repaired, for example a tendon. By virtue of the proposed solutions, a bio-compatible and bio-resorbable implantable device is provided, suitable to fully degrade within the organism of a human or animal patient within a reasonable time for the tissue repair of the soft tissue to be repaired, for example a tendon, avoiding the release of solid residues at the implantation site. The provision of such a bio-compatible and bio-resorbable implantable device avoids the need to extract the implantable device from the implantation site. 
     By virtue of the proposed solutions, the patient is placed in the conditions to achieve a faster and more satisfactory functional recovery. 
     By virtue of the proposed solutions, the risk of excess scar tissue forming in the soft tissue to be repaired is avoided. 
     By virtue of the proposed solutions, a physiological imbibition of the soft tissue to be repaired is allowed at or near the tissue lesion, promoting in an unusual way the regeneration of the soft tissue, for example tendon regeneration. 
     The bio-compatible and bio-resorbable implantable device is particularly suitable, although not uniquely intended, for implantation in a human patient, for example to repair the Achilles tendon as well as the patellar-femoral tendon, biceps, finger flexors, hand flexors, foot flexors, anterior tibialis, patellar tendon, and tendons of the quadriceps, biceps, and rotator cuff. 
     The bio-compatible and bio-resorbable implantable device is also suitable for implantation in an animal patient, such as a racehorse. 
    
    
     
       FIGURES 
       Further features and advantages of the implantable device and of the assembly according to the invention will appear from the description given below of its preferred embodiments, given by way of non-limiting example, with reference to the attached figures, wherein: 
         FIG.  1    is a perspective view showing a portion of a soft tissue to be repaired and a bio-compatible and bio-resorbable implantable device inserted in said soft tissue, according to an embodiment; 
         FIG.  2    is a schematic perspective view of a bio-compatible and bio-resorbable implantable device, according to an embodiment, implanted to repair a tendon, shown by way of example as completely severed into two stumps; 
         FIG.  3    is a perspective view showing in separate parts a bio-compatible and bio-resorbable implantable device, according to an embodiment; 
         FIG.  4    is a sectional view taken according to the cutting plane indicated by the arrows IV of  FIG.  3   ; 
         FIG.  5 A  shows a perspective view of a perforating device, according to an embodiment; 
         FIG.  5 B  is a sectional perspective view made according to the cutting plane indicated by the arrows V of  FIG.  5 A ; 
         FIG.  5 C  is a plan view according to the point of view indicated by the arrow C of  FIG.  5 B ; 
         FIG.  6 A- 6 C  show in schematic section the implantation of a bio-compatible and bio-resorbable implantable device shown in  FIG.  3    (with transparent soft tissue for clarity); 
         FIG.  7    is a perspective view showing in separate parts a bio-compatible and bio-resorbable implantable device, according to an embodiment; 
         FIG.  8    is a sectional view taken according to the cutting plane indicated by the arrows VIII of  FIG.  7   ; 
         FIG.  9 A- 9 D  show in schematic section the implantation of a bio-compatible and bio-resorbable implantable device shown in  FIG.  7    (with transparent soft tissue for clarity); 
         FIG.  10    is a perspective view showing in separate parts a bio-compatible and bio-resorbable implantable device, according to an embodiment; 
         FIG.  11    is a sectional view taken according to the cutting plane indicated with the arrows XI of  FIG.  10   ; 
         FIG.  12 A- 12 D  show in schematic section the implantation of a bio-compatible and bio-resorbable implantable device shown in  FIG.  10    (with transparent soft tissue for clarity); 
         FIG.  13 A  shows a perspective view in separate parts of a perforating device, according to an embodiment; 
         FIG.  13 B  shows in section a portion of the perforating device shown in  FIG.  13 A ; 
         FIG.  14 A  shows a perspective view in separate parts of a perforating device, according to an embodiment; 
         FIG.  14 B  shows in section a portion of the perforating device shown in  FIG.  14 A . 
     
    
    
     DETAILED DESCRIPTION OF SOME EMBODIMENTS 
     According to a general embodiment, a bio-compatible and bio-resorbable implantable device  10  is provided for repairing a soft tissue  1 , and preferably for repairing a tendon  1 . 
     “Soft tissue  1 ” preferably refers to a soft tissue suitable to be stressed in extension when in physiological conditions, such as for example a tendon  1 . 
     In the following description the term “tendon  1 ” will be used, referring, where applicable, also to “ligament  1 .” The bio-compatible and bio-resorbable implantable device  10  is also suitable for repairing ligament tissue  1 . 
     The implantable device  10  comprises at least two bio-compatible and bio-resorbable plates  11 ,  12  comprising a first plate  11  and a second plate  12 . 
     The plates  11 ,  12  are made in separate pieces from one another and are interlockable with each other. 
     The first plate  11  may be made in a single piece. The second plate  12  may be made in a single piece. 
     The implantable device  10  further comprises a plurality of bio-compatible and bio-resorbable connecting elements  20  suitable for connecting said first plate  11  and said second plate  12  together. For example, said bio-compatible and bio-resorbable connecting elements  20  comprise pins  24 ,  24 ′,  24 ″ and hole rims  23  which receive a portion of said pins  24 ,  24 ′,  24 ″. 
     The tendon  1  to be repaired comprises a tendon body  2  which is pathologically interrupted forming a tendon lesion  5 . The tendon lesion  5  may involve the entire cross section of the tendon  1  defining two tendon stumps or only a part thereof. 
     The tendon lesion  5  may refer to a stretch of tendon  1  not necessarily interrupted and therefore not having clear geometric discontinuity but nevertheless unable to effectively transmit the forces in the length concerned. 
     The first plate  11  comprises a first surface  13  suitable for being placed on a first side  3  of the tendon  1  to be repaired. Preferably, the first surface  13  of the first plate  11  is placed on a portion of the first tendon side  3  which comprises said tendon lesion  5 . In other words, the first surface  13  is placed on the tendon lesion  5 , substantially straddling said lesion. 
     The second plate  12  comprises a second surface  14 , suitable for being placed on a second side  4  of the tendon  1  to be repaired, opposite to said first side  3  of the tendon  1  to be repaired with respect to the body  2  of said tendon to be repaired. Preferably, the second surface  14  of the second plate  12  is placed on a portion of the second tendon side  4  which comprises said tendon lesion  5 . In other words, the second surface  14  is placed on the tendon lesion  5 , substantially straddling said lesion. 
     In this way, the first plate  11  and the second plate  12  of the implantable device  10  are intended to be implanted whereby they are mutually contraposed and facing each other and separated by the body  2  of the tendon  1  to be repaired in the portion where the tendon lesion  5  is present. In other words, the first plate  11  and the second plate  12  are both arranged to cover the tendon lesion  5  on opposite sides  3 ,  4  of the body  2  of the tendon  1 . Preferably, the body  2  of the tendon  1  is formed of a plurality of fibers or filaments which extend in the preferential direction of load transfer of said tendon  1 , and the lesion  5  may be extended in a direction transverse to the preferential direction of load transfer, i.e., transversely to the fibers. The lesion  5  may be extended also at least partially substantially aligned with the fibers of the soft tissue  1  to be repaired, such as for example a tendon  1 . 
     Advantageously, said plurality of connecting elements  20  of the implantable device  10  extend from at least one of said first surface  13  of the first plate  11  or said second surface  14  of the second plate  12  to reach the other of said first surface  13  of the first plate  11  and said second surface  14  of the second plate  12 . 
     Preferably, the length of these connecting elements  20  is so as not to protrude beyond the back of the plates  11 ,  12 , avoiding causing friction with the surrounding tissues which could inflame these surrounding tissues and could hinder the movement of the implantable device  10  integral with the tendon  1  during physiological movements of the tendon  1 . 
     With a further advantage, the purpose of said plurality of connecting elements  20  is to lock said first plate  11  and said second plate  12  in a definable respective position. 
     In this way, the positioning elements  20  act as positioning elements for the plates  11 ,  12  with respect to the tendon  1  to be repaired. 
     Preferably, the plates  11 ,  12  are locked together in a respective configuration by the connecting elements  20 , avoiding the presence of residual degrees of freedom of mutual movement between the plates  11 ,  12 . 
     The plates  11 ,  12  therefore perform the dual function of transmitting forces in the tract wherein they are not transmissible along the injured tendon, as well as maintaining the relative position of the tendon tracts, maintaining the diastasis between the two tendon stumps within a physiological distance which allows tissue regeneration between said two stumps. 
     The first surface  13  and the second surface  14  intended to come into contact on opposite sides  3 ,  4  of the tendon  1  to be repaired may preferably be worked so as to be made smooth, thus reducing the risk of inflammation of the tendon to be repaired due to chafing by friction. 
     According to an embodiment, at least some connecting elements of said plurality of connecting elements  20  of the implantable device  10  extend in the form of protrusions  24 ,  24 ′,  24 ″ from the first surface  13  of the first plate  11 . 
     According to an embodiment, at least some connecting elements of said plurality of connecting elements  20  of the implantable device  10  extend in the form of protrusions  24 ,  24 ′,  24 ″ from the second surface  14  of the second plate  12 . 
     Preferably, when the implantable device  10  is implanted, each connecting element  20  extends from said first surface  13  to said second surface  14 , although at least one connecting element or each connecting element  20  may be made in at least two separate pieces, i.e. a first piece  21  or first portion  21  integral with the first plate  11  and a second piece  22  or second portion  22  integral with the second plate  12 , defining a locking portion  28  which, when the implantable device  10  is implanted, may be embedded in the body  2  of the tendon  1 . 
     In the event that at least one connecting element or each connecting element extends from said first surface  13  to said second surface  14  without interruption, the locking portion  28  will be placed near one of said first plate  11  or said second plate  12 . In this case, for example, the second portion  22  of the connecting element  20  will be formed by the rim of a hole  23  integral with the second plate  12 . 
     According to a preferred embodiment, each connecting element of said plurality of connecting elements  20  comprises two portions  21 ,  22  which are interlockable with each other, forming a plurality of locking portions  28 . In this way, it is possible to lock said first plate  11  and said second plate  12  together. 
     The portions of each connecting element  20  may interlock in various ways. 
     According to an embodiment, the two portions  21 ,  22  of a connecting element  20  interlock by undercut coupling, wherein a first portion  21  of the connecting element integral with the first plate  11  comprises a first abutment surface  25  facing the first surface  13  of the first plate  11 , so as to couple against a second abutment surface  26  of the second plate  12  opposed or contraposed to the second surface  14  of the second plate  12 . For example, the second abutment surface  26  may be placed on the back  19  of the second plate  12 . 
     According to an embodiment, said protrusions  24 ,  24 ′,  24 ″, which form at least one of said first portion  21  or said second portion  22  of each connecting element  20 , comprise a head  29  having a tip  43  which is convex. The provision of the convex tip  43  of the head  29  of a first or second portion  21 ,  22  of a connecting element avoids inflaming the tendon  1  to be repaired during the implantation of the bio-compatible and bio-resorbable implantable device  10 . 
     According to an embodiment, said protrusions  24 ,  24 ′,  24 ″, which form at least one of said first portion  21  or said second portion  22  of each connecting element  20 , a convex base  42 , for example substantially circular, and a lateral surface  44  without sharp edges, for example cylindrical or frusto-conical. The provision of a first or second portion  21 ,  22  of a connecting element without sharp edges, for example substantially frusto-conical or cylindrical, avoids inflaming the tendon  1  to be repaired. 
     The lateral surface may extend from the base  42  to the head  29 . The head  29  may form an undercut surface facing the base  42  which acts as the abutment surface  25  or  26 . For example, the lateral surface and the head  29  form a substantially mushroom-shaped element. 
     As shown for example in  FIG.  4   , the first portion  21  of the connecting element comprises a head  29 , preferably having a circular base  42  and a convex tip  43  and forming a first abutment surface  25  facing the first surface  13  of the first plate  11 , the first abutment surface  25  engages in an undercut against a second abutment surface  26  of the second plate  12  facing opposite to the second surface  14  of the second plate  12 . In this case, the second portion  22  of the connecting element integral with the second plate  12  is formed of the rim of the hole  23 . 
     According to an embodiment, the two portions of a connecting element  20  interlock by latching. 
     According to an embodiment, the two portions of a connecting element  20  interlock by snap-fitting following an elastic deformation of a portion of the connecting element. 
     According to an embodiment, the two portions of a connecting element  20  interlock by force fitting or interference fitting, wherein the deformation of at least a portion of the connecting element interlocks with the first plate  11  and the second plate  12  by friction. 
     According to an embodiment, the two portions of a connecting element  20  interlock by hook-loop coupling, such as, for example, by means of Velcro®. 
     According to an embodiment, the two portions of a connecting element  20  interlock by a combination of the methods described above. 
     When the implantable device  10  has been implanted and has been bio-resorbed, it will be dissolved, and the body  2  of the tendon  1  will have healed the lesion  5  and is preferably indistinguishable from said tendon before the formation of the lesion  5 . 
     According to an embodiment, said first plate  11  and said second plate  12  each have a closed and continuous plate edge  15 ,  16 , wherein the edge  15  of the first plate  11  defines the perimeter of said first surface  13  of the first plate  11 , and wherein the edge  16  defines the perimeter of said second surface  14  of the second plate  12 . 
     According to an embodiment, said plurality of connecting elements  20  extend from said first surface  13  of the first plate  11  to said second surface  14  of the second plate  12  substantially straight, i.e., in a substantially straight line, in a direction transverse to the extension of the plates  11 ,  12 . The substantially straight extension lines of the connecting elements are preferably parallel to each other, minimizing the length of these connecting elements. 
     In this way, it is possible to maximize the resistance of the bio-compatible and bio-resorbable connecting elements  20  and likewise the resistance that the implantable device  10  offers to the respective distancing of the margins of the lesion  5  of the tendon  1  to be repaired. 
     According to an embodiment, at least some connecting elements of said plurality of connecting elements  20  are formed by a blind or through hole  23  positioned on said first plate  11  or said second plate  12  and by a protrusion  24  positioned on the other of said first plate  11  or said second plate  12  in a position facing said blind or through hole  23 . 
     According to an embodiment, at least some connecting elements of said plurality of connecting elements  20  are formed of a first protrusion  24 ′, which extends from said first plate  11 , and a second protrusion  24 ″, which extends from said second plate  12  in a position facing said first protrusion  24 ′, wherein said first protrusion  24 ′ defines said blind or through hole  23 , and wherein said second protrusion  24 ″ defines said head  29 , which, as shown for example in  FIG.  10   , may have a polygonal base  42  and a sharp tip portion  43 . Preferably, said first protrusion  24 ′ defines said hole  23  in a substantially discoidal internal seat cavity  41 , forming at least one first abutment surface  25  contraposed with respect to the first surface  13  of the first plate  11 . Preferably, said second protrusion  24 ″ defines a second abutment surface  26  facing said second surface  14  of the second plate  12 . 
     According to an embodiment, said plurality of connecting elements  20  are arranged on arrays S 1 , S 2  or rows, wherein the connecting elements of a first array S 1  are arranged staggered with respect to the connecting elements of a second array S 2  contiguous to said first array S 1 . Preferably, the arrays S 1 , S 2  follow each other in a direction transverse to the direction of extension of the plurality of connecting elements  20  and transverse to the preferential direction of transmission of the forces of said tendon  1 . 
     The lateral surfaces  44  of the connecting elements  20  form positioning abutments for the fibers of the tendon  1  to be repaired which promote the healing of the lesion  5 . The lateral surfaces of the connecting elements  20  are preferably curved, avoiding sharp edges which could damage the body  2  of the tendon to be repaired both during implantation and when implanted inside the body  2  of the tendon  1  to be repaired. 
     The curved lateral surfaces of the connecting elements  20  also allow the mechanical strength of the connecting elements to be maximized. 
     According to an embodiment, said plurality of connecting elements  20  keep said first surface  13  of the first plate  11  and said second contraposed surface  14  of said second plate  12  apart by a distance  40 , forming one or more windows  17  delimited at least partially by both said first plate  11  and said second plate  12  and suitable for exposing a portion of the tendon  1  to the surrounding environment. Preferably, said one or more windows  17  are delimited by both plate edges  15 ,  16  of said first and second plate  11 ,  12 . 
     The windows  17  allow for the vascularization of the tendon  1  at or near the lesion  5  when the implantable device  10  has been implanted. 
     According to a general embodiment, an assembly  30  for repairing a soft tissue  1 , for example a tendon  1 , comprises at least one bio-compatible and bio-resorbable implantable device  10  according to any of the embodiments described above. 
     Said assembly  30  further comprises a non-implantable perforating device  31  made in a separate piece with respect to said bio-compatible and bio-resorbable implantable device  10 . Preferably, said perforating device  31  is made in the form of a third perforating plate  31 . 
     Said perforating device  31  comprises a plurality of perforating elements  33  suitable for making through perforations  32  in said tendon  1  to form positioning paths for said plurality of connecting elements  20  of the bio-compatible and bio-resorbable implantable device  10 . 
     According to an embodiment, said plurality of perforating elements  33  each delimit a longitudinal through cavity  34  for the insertion of at least one portion  21  or  22  of the connecting elements of said plurality of connecting elements  20  of the bio-compatible and bio-resorbable implantable device  10 . In this way, the perforating elements are fitted onto the connecting elements  20  during implantation of the implantable device  10 . 
     According to an embodiment, said at least one portion  21  or  22  of the connecting elements  20  of said plurality of connecting elements  20  delimits a longitudinal through cavity  34 ′ for the insertion of said plurality of perforating elements  33  of the perforating device  31 . In this way, the connecting elements  20  of the implantable device  10  are fitted onto the perforating elements  33  of the perforating device  31 , during the implantation of the implantable device  10 . 
     According to an embodiment, said perforating device  31  comprises a support  36  from which said perforating elements  33  extend. The support  36  is preferably a plate so that the perforating device  31  forms a further third plate  31  of the assembly  30 . 
     Preferably, the perforating elements  33  each comprise a sharp perforating end  35 , obtained for example on the cylindrical rim of each perforating element  33 . 
     According to an embodiment, the perforating elements  33  are made in separate pieces with respect to the support  36  and fixed thereto through fastening means. Said means for fastening the perforating elements  33  to the support  36  are preferably threaded fastening means of the screw-nut type, whereby the perforating elements  33  are screwed to the support  36 . 
     According to an embodiment, each perforating element  33  is individually screwed to the support  36  by means of a fastening screw  38 . The term “screw” also refers to a fastening grub screw  38 . According to an embodiment, each perforating element  33  comprises a fastening root  45  opposite to the sharp perforating end  35  screwed to the support  36 . The fastening root  45  may be screwed to the support  36  by tapping the fastening root  45 . Preferably, the fastening root  45  is screwed to the support  36  by providing a threaded seat  39  in the fastening root which engages with a fastening screw  38 , attaching itself to the support  36 . The support  36  may be provided with through holes  46  to allow the fastening screw  38  to screw into the threaded seat  39  of the fastening root  45  of the perforating element  33 . The fastening screw  38  may be inserted from the back  47  of the support  36 , in other words from the face of the support facing opposite to the perforating elements  33 . The through holes  46  of the support  36  may each comprise an abutment projection  48 , for example an internal abutment crown  48 , and the fastening root  45  abuts against the abutment crown  48 . The fastening root  45  may be provided with an abutment counter-ridge  49 , for example a fastening flange  49  which abuts against the abutment crown  48 . The abutment projection  48  may form a further abutment surface for the head of the fastening screw  38 . The fastening screw  38  may also be screwed to the walls  39 ′ of the through hole  46  of the support  36 . 
     The perforating elements  33  may be welded or glued to the support  36 . 
     The perforating device  31  may be made of any rigid material, re-sterilizable, and suitable for perforation, such as for example titanium or other surgical metal. 
     According to an embodiment, the support  36  comprises a thrust surface  37  intended to abut against the plate back  19  of at least one of said first plate  11  or said second plate  12  during the implantation of the implantable device  10 , to push the connecting elements  20  inside the through perforations  32  made by the perforating elements  33  inside the body  2  of the tendon  1 . In this way it is possible to push at least one of said first plate  11  or said second plate  12  against the surface of the soft tissue  1  to be repaired. 
     Preferably, the longitudinal extension of each perforating element  33  is greater than the longitudinal extension of the associable first portion  21  of the connecting element  20 , but not excessively greater, so as to make its use practical in the operative phase. 
     The provision, during the implantation of the implantable device  10  of said perforating device  31  equipped with said perforating elements  33 , which are fitted onto said connecting elements  20 , as well as said connecting elements  20 , fitted on said perforating elements  33 , allows the insertion of the bio-compatible and bio-resorbable implantable device  10  to be guided through the body  2  of the tendon  1  to be repaired. 
     The arrangement of the perforating elements  33  on the support  36  of the perforating device  31  is preferably coordinated with and corresponding to the arrangement of the connecting elements  20  on the plates  11 ,  12 . In this way, the perforating elements  33  are also arranged in arrays or rows S 1 , S 2 . 
     As shown for example in  FIG.  6 A- 6 C , the implantation of the implantable device  10  may occur by:
         approaching the sharp perforating tips  35  of the perforating elements  33  of the perforating device  31  to one side  4  of the tendon  1  to be repaired near the lesion  5 ;   making through perforations  32  inside the body  2  of the tendon  1  by inserting said perforating elements  33  inside the body  2  of the tendon  1 ;   approaching from the side  3  of the body  2  of the tendon  1  the first plate  11  provided with the first portions  21  of the connecting elements  20 ;   inserting the first portions  21  of the connecting elements  20  into the longitudinal through cavities  34  of the perforating elements  33 ;   penetrating the first plate  21  into the body  2  of the tendon  1  and at the same time extracting the perforating device  31  from the body  2  of the tendon  1 , until the tips of said first portions  21  of the connecting elements  20  emerge from the opposite side  4  of the body  2  of the tendon  1 ;   applying the second plate  12  on the side  4  of the body  2  of the tendon  1  so that its second portions  22  of the connecting elements  20 , for example, holes  23 , interlock by latching in an undercut with the first portions  21  of the connecting elements  20 , forming said locking portions  28 .       

     As shown for example in  FIG.  9 A- 9 D , the implantation of the implantable device  10  may occur by:
         fitting the first portions  21  of the connecting elements  20  of the first plate  11  provided with longitudinal through holes  34 ′ on the perforating elements  33  of the perforating device  31 , so that the sharp perforating tips  35  protrude from the tips of the first portions  21  of the connecting elements  20  of the first plate  11 , and preferably bringing the back  19  of the first plate  11  in abutment against said thrust surface  37  of the support  36  of the perforating device  31 ;   approaching the perforating elements  33  and said first portions  21  of the connecting elements  20  fitted thereon to one side  3  of the tendon  1 ;   making through perforations  32  inside the body  2  of the tendon  1  by inserting said perforating elements  33  inside the body  2  of the tendon  1  and at the same time guiding the insertion of said first portions  21  of the connecting elements  20  thereon fitted inside the body  2  of the tendon  1 , until the tips of said first portions  21  of the connecting elements  20  emerge from the opposite side  4  of the body  2  of the tendon  1 ;   approaching the second plate  22  to the side  4  of the body  2  of the tendon  1 ;   extracting the perforating elements  33  of the perforating device  31  and at the same time applying the second plate  12  on the side  4  of the body  2  of the tendon  1  so that its second portions  22  of the connecting elements  20 , for example through holes  23 , interlock and latch by means of an undercut with the first portions  21  of the connecting elements  20 , forming said locking portions  28 .       

     As shown for example in  FIG.  12 A- 12 D , the implantation of the implantable device  10  may occur by:
         fitting the first portions  21  of the connecting elements  20  of the first plate  11  provided with longitudinal through holes  34 ′ on the perforating elements  33  of the perforating device  31 , so that the sharp perforating tips  35  protrude from the tips of the first portions  21  of the connecting elements  20  of the first plate  11 , and preferably bringing the back  19  of the first plate  11  into abutment against said thrust surface  37  of the support  36  of the perforating device  31 ;   approaching the perforating elements  33  and said first portions  21  of the connecting elements  20  fitted thereon to one side  3  of the tendon  1 ;   making through perforations  32  inside the body  2  of the tendon  1  by inserting said perforating elements  33  inside the body  2  of the tendon  1  and at the same time guiding the insertion of said first portions  21  of the connecting elements  20  fitted thereon inside the body  2  of the tendon  1 , until the tips of said first portions  21  of the connecting elements  20  emerge from the opposite side  4  of the body  2  of the tendon  1 ;   approaching the second plate  22  to the side  4  of the body  2  of the tendon  1 ;   extracting the perforating elements  33  of the perforating device  31  and at the same time applying the second plate  12  on the side  4  of the body  2  of the tendon  1  so that its second portions  22  of the connecting elements  20 , for example protrusions  24 ″, interlock by latching in an undercut with the first portions  21  of the connecting elements  20 , forming said locking portions  28 .       

     The bio-compatible and bio-resorbable implantable device  10  may be made of a material which is obtained by mixing two or more biopolymers in order to provide optimal mechanical characteristics of tensile strength ensuring their biocompatibility and bioresorbability. For example, said bio-compatible and bio-resorbable implantable device  10  is made by means of a mixture of polylactic acid, PLA, and polycaprolactone, PCL. By acting on the composition of the mixture it is possible to obtain a regulation of the mechanical properties as well as of the degradation rate, in other words the bio-resorption rate, which must allow the connecting elements  20 , particularly the protrusions  24 ,  24 ′,  24 ″, and preferably also the plates  11 ,  12 , a bio-resorption time congruent with the time of repair of the soft tissue  1 , for example a tendon  1 . 
     Preferably, the bio-compatible and bio-resorbable polymeric mixture degrades through a process of hydrolysis in a physiological environment, the loss of mass may preferably occur through bioerosion in the entire volume (i.e. “in bulk”) or superficially. The connecting elements  20 , and particularly the protrusions  24 ,  24 ′,  24 ″, may have different mechanical properties, bio-resorption properties, bio-erosion properties and different composition with respect to the plates  11 ,  12 . 
     According to an embodiment, connecting elements  20 , and particularly the protrusions  24 ,  24 ′,  24 ″, are made of a material having an elastic modulus between 0.2 gigapascals and 4 gigapascals. Preferably, the elastic modulus is comprised between 0.2 gigapascals and 3 gigapascals. According to one embodiment, the elastic modulus is between 0.9 gigapascals and 2.6 gigapascals. The plates  11 ,  12  may have an elastic modulus equal to or less than that of the connecting elements  20 , and particularly of the elastic modulus of the protrusions  24 ,  24 ′,  24 ″. The elastic modulus of the implantable device  10  may be comparable to that of the soft tissue  1 . 
     The bio-compatible and bio-resorbable implantable device  10  may be fabricated by additive manufacturing, such as 3D printing. 
     The bio-compatible and bio-resorbable implantable device  10  may be fabricated by soft-lithography, soft-tooling or other similar technologies. 
     By virtue of the features described above provided severally or jointly with each other in particular embodiments, it is possible to obtain a bio-compatible and bio-resorbable implantable device as well as an assembly, which at the same time satisfies the above-described requirements, conflicting with each other, and the aforementioned desired advantages, and in particular:
         the bio-compatible and bio-resorbable implantable device may be firmly positioned without needing to be fastened or tied to the tendon to be repaired;   the risk of inflammation of the tendon to be repaired is avoided or at least minimized;   a solution is provided that may be applied to various types of soft tissues, for example tendons and ligaments;   the bioresorbability of the implantable device allows a gradual progressive distribution over time of the physiological tensile loads on the tendon to be repaired during the healing of the tendon, promoting its complete functional recovery;   the need for sutures is avoided;   the plates are interlockable because the connecting elements are interlockable;   it is unnecessary to provide cables or other elements to connect the two plates or keep them connected after the installation;   the pins or protrusions that form the connecting elements do not injure the soft tissue to be repaired but allow a firm locking in a single respective position of the two plates;   the connecting elements between the plates are suitable for inserting between the fibers of the tendon to be repaired, avoiding interrupting or damaging them, thus promoting their healing;   the provision of a perforating device allows jamming stresses on the connecting elements to be avoided, which therefore may include fine mechanical processing, for example with undercutting and/or grooves and bottlenecks, and may be made with mechanical properties, for example stiffness, comparable to those of the soft tissue to be repaired;   the assembly is made up of three plates  11 ,  12 ,  31 , of which two plates  11 ,  12  are implantable, bio-compatible and bio-resorbable, interlockable, without requiring sutures or the like, and a third non-implantable perforating plate  31 .       

     A person skilled in the art, in order to satisfy contingent and specific needs, may make numerous modifications and adaptations to the embodiments described above, and replace elements with other functionally equivalent ones, without however departing from the scope of the following claims. 
     LIST OF REFERENCES 
     
         
           1  Soft tissue, or tendon, or ligament 
           2  Body of the tendon 
           3  First side of the tendon 
           4  Second side of the tendon 
           5  Tendon lesion 
           10  Bio-compatible and bio-resorbable implantable device 
           11  First bio-compatible and bio-resorbable plate 
           12  Second bio-compatible and bio-resorbable plate 
           13  First surface of the first plate 
           14  Second surface of the second plate 
           15  Edge of the first plate 
           16  Edge of the second plate 
           17  Window 
           19  Plate back 
           20  Bio-resorbable and bio-compatible connecting elements 
           21  First portion, or first piece, of the connecting element 
           22  Second portion, or second piece, of the connecting element 
           23  Connecting element hole 
           24 ,  24 ′,  24 ″ Protrusion of connecting element 
           25  First abutment surface of the first portion of the connecting element 
           26  Second abutment surface of the second portion of the connecting element 
           28  Locking portion, or interlocking portion 
           29  Head of connecting element 
           30  Assembly 
           31  Perforating device of the assembly, or third perforating plate 
           32  Perforation in the soft tissue 
           33  Perforating element of the perforating device 
           34  Longitudinal through channel of the perforating device 
           34 ′ Longitudinal through channel of the connecting element 
           35  Sharp perforating tip 
           36  Support of the perforating device 
           37  Thrust surface of the perforating device 
           38  Fastening screw 
           39 ,  39 ′ Threaded seat 
           40  Distance 
           41  Internal seat cavity of connecting element 
           42  Polygonal base of connecting element 
           43  Tip of connecting element portion 
           44  Lateral surface 
           45  Fastening root of the perforating element 
           46  Through hole of the support 
           47  Back of the support 
           48  Abutment ridge, for example internal abutment crown 
           49  Abutment counter-ridge, for example abutment flange 
         S 1  First array or first row 
         S 2  Second array or second row