Abstract:
A surgical suture anchor element serves for anchoring at least one suture in a bore. An elongated body has a central bore for receiving a tool. The central bore is surrounded by a jacket of considerable substance. For receiving the suture, slits or channels or eyelet members are alternatively provided in or at the jacket.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The invention relates to a surgical suture anchor element for introduction into a bone, with at least one suture for fixing a tendon, a ligament or soft tissue, with at least one opening for receiving the at least one suture, and with a central bore for receiving a tool for introducing the anchor element.  
         [0002]     Such anchor elements are known from U.S. Pat. No. 6,139,565, for example.  
         [0003]     These anchor elements, also referred to as suture anchors, are used in surgery for fixing a torn tendon, a ligament or other tissue back onto the bone with the aid of a suture. They can also be used for fixation of soft tissue, for example in labrum refixation.  
         [0004]     As regards the design of the anchor elements, the primary aim is to ensure that a suture for fixing the torn tendon is held securely by the introduced anchor element. This assumes similar considerations regarding the design of a suture holder in the anchor element.  
         [0005]     One of the main fields of application for such anchor elements is the fixing of torn tendons in the shoulder region.  
         [0006]     An example of such an anchor element is shown in FIGS. 8A to 8F of aforementioned U.S. Pat. No. 6,139,565.  
         [0007]     The anchor element shown there comprises an elongate, cylindrical body with a central bore. This central bore is designed as a channel with a square cross section routed axially through the anchor element and serves to receive the rotary tool used for turning the anchor element into the bone.  
         [0008]     On a proximal portion of the anchor element, four webs are arranged in a cross formation around the opening of the channel, and a suture eyelet is cut out in each of these webs.  
         [0009]     Since the suture eyelets are intended to receive and hold the suture, it is considered disadvantageous that the suture eyelets are cut out in proximally projecting webs. The webs as such already constitute areas of material weakness in the body of the anchor element, and they are further weakened by the suture eyelets.  
         [0010]     The suture is threaded into the narrow suture eyelets of the anchor element.  
         [0011]     After the anchor element has been fitted in place, the rotary tool is removed. The tendon is then fixed using the ends of the suture protruding from the bore. Considerable forces act on the suture eyelet both during fixation and also in the postoperative phase. With suture eyelets formed in narrow webs of thin material, there is a danger of the suture coming loose from the anchor element as a result of the material breaking. Narrow webs constitute points of minimal surface contact with the suture and, as a result of movements, promote fraying of the suture.  
         [0012]     Since anchor elements made of absorbable materials are also used in modern medicine, that is to say materials that can gradually be replaced by endogenous bone substance, a problem arises due to the materially thin design of the suture eyelet.  
         [0013]     This problem entails the danger of the suture eyelet being torn off or broken off, which may lead to serious complications especially in the later stages during the healing process.  
         [0014]     It is therefore an object of the present invention to make available an anchor element of the type mentioned in the introduction which provides improved stability for a suture holder.  
       SUMMARY OF THE INVENTION  
       [0015]     According to the invention, the object is achieved, in one alternative, by an anchor element having an elongated body, said body having a central bore for receiving a tool for introducing said anchor element into said bone, said body having a proximal end section surrounding said central bore, said end section being designed as a jacket of considerable substance, wherein at least one slit is provided in said jacket of considerable substance, said slit opens laterally to a radial outer face of said body, said at least one slit extending in a circumferential direction within said jacket of considerable substance, and said at least one suture is received within said at least one slit.  
         [0016]     Within the meaning of the present invention, a “central bore” is to be understood both as a blind hole and also as a continuous channel.  
         [0017]     The expression “jacket of considerable substance” is to be understood as a portion of the anchor element that surrounds the central bore in the proximal area. This portion is unweakened by material reduction and is therefore particularly well suited for receiving suture guides. This portion has a thick wall of material.  
         [0018]     A suture holder in the form of a slit of this design offers the suture a correspondingly large contact surface. This contact surface extends about part of the circumference of the jacket of considerable substance of the anchor element. In this way, the forces acting on the suture are passed on by it to a solid portion of the anchor element.  
         [0019]     The greater the part of the circumference in which the suture is received in the anchor element, the greater also is the contact surface of the suture. In this way, the forces acting on the suture are conveyed uniformly to the anchor element across a greater surface area, and locally concentrated forces are avoided. This protects the suture holder from being torn out or broken off, and it also protects the suture during relative movements between the suture and the anchored anchor element.  
         [0020]     This embodiment also has the advantage that the suture holder and the course of a central bore in the anchor element can be kept spatially separate from one another.  
         [0021]     This allows the depth of the central bore to be adapted to different designs of rotary tools, independently of the design of the suture receiving part. In this way, an optimal depth of introduction of a tool into the anchor element is ensured.  
         [0022]     In addition, insertion of the suture is made easier, since the latter needs only to be pushed into the slit. This avoids the suture and the rotary tool getting in each other&#39;s way.  
         [0023]     In one embodiment, the at least one slit has flanks that extend in parallel.  
         [0024]     This measure has the advantage that the slit, for example in an anchor element made of metal, can be easily produced by milling. In the case of absorbable materials, such an anchor element can be easily produced in an injection-molding operation.  
         [0025]     In another embodiment, the at least one slit has flanks that diverge.  
         [0026]     This measure has the advantage that the slit is widened laterally toward the radial outer surface by the diverging flanks. This widened slit makes inserting the suture easier. In this case, the flanks can be formed in the anchor element in such a way that, by pulling the received suture in the proximal direction, said suture easily slides radially inward into the slit and remains there as long as the suture is held taut.  
         [0027]     In another embodiment, the flanks are beveled at their edges.  
         [0028]     This measure has the advantage that beveling the edges prevents the suture from becoming damaged by fraying or from being severed.  
         [0029]     In another embodiment, the slits are inclined relative to the longitudinal axis of the anchor element.  
         [0030]     This measure has the advantage that the slits can be formed in the anchor element in such a way that, by pulling the received suture in the proximal direction, said suture easily slides radially inward into the slit and remains there. A suture, once it has been received and tensioned, remains In the inclined slit of the anchor element. A secure hold of the suture is therefore guaranteed as long as the suture is held taut in the anchor element.  
         [0031]     The anchor element, which is pushed onto the tool, can be secured captive on the tool with the aid of the taut suture. This permits reliable introduction of the anchor element into the bone.  
         [0032]     In another embodiment, the inclination has an angle of approximately 10° to approximately 80°.  
         [0033]     This measure has the advantage that the slit, in terms of its inclination, can be designed differently depending on the intended use and design of the anchor element.  
         [0034]     This permits an inclination that is sufficiently steep to ensure that a received suture can still be held securely in the slit even if the tensioning is relaxed. These variations are possible by virtue of the jacket of thick material.  
         [0035]     In another embodiment, the at least one slit has a rounded base.  
         [0036]     This measure has the advantage that the suture can to a certain extent execute transverse movements in the slit, the possibility of fraying being ruled out in the rounded base.  
         [0037]     In another embodiment, the rounded base has a curved course.  
         [0038]     This measure has the advantage that, in a base with a curved course, the suture bears over a relatively long portion of the slit. This avoids local points of contact for the suture. In this way, tensile forces that arise are conveyed uniformly to the anchor element.  
         [0039]     In another embodiment, the curved course is U-shaped.  
         [0040]     This measure has the advantage that a U-shaped course of the curvature allows proximally directed forces on the suture to be conveyed optimally to the anchor element.  
         [0041]     In another embodiment, the anchor element has several slits.  
         [0042]     This measure has the advantage that several sutures can be received in the slits in the anchor element. In this way, tensile forces are distributed across different sutures and positions in the anchor element and are thereby reduced. For this reason, these tensile forces are conveyed more uniformly to the anchor element.  
         [0043]     In another embodiment, the anchor element has two slits.  
         [0044]     This measure has the advantage that two slits in the anchor element represent a very good compromise between the aforementioned advantages and the material removed from the anchor element.  
         [0045]     In another embodiment, the slits are arranged diametrically in the anchor element.  
         [0046]     This measure has the advantage that securing the anchor element on the tool with the aid of the sutures threaded into the slits takes place in a uniform manner. Forces that act on the anchor element during introduction are in this way distributed uniformly.  
         [0047]     In addition, the anchor element and also the sutures are thus secured captive on the tool during introduction.  
         [0048]     This measure also has the advantage that tensile loads acting on the inserted sutures are conveyed to the bone at opposite parts of the anchor element that has been introduced. This ensures uniform loading of the anchor element in a loading situation in the bone. Damage to the anchor element by locally delimited peak forces is thus ruled out.  
         [0049]     The object is achieved, in another and second alternative, by an anchor element having an elongated body, said body having a central bore for receiving a tool for introducing said anchor element into said bone, said body having a proximal end section surrounding said central bore, said end section being designed as a jacket of considerable substance, wherein at least one approximately U-shaped channel being provided in said jacket of considerable substance, said at least one U-shaped channel opens in a proximal end face of said jacket of considerable substance, said at least one suture is received in said at least one U-shaped channel.  
         [0050]     These measures have the advantage that a suture placed in the channel and subjected to tensile stress bears tightly and uniformly against a channel wall and thus ensures uniform distribution of the tensile force over a portion of the channel.  
         [0051]     The anchor element can also be designed to meet different levels of tensile forces, by means of the channel being formed to a suitable depth in the anchor element. This is supported by the fact that the channel is located in the jacket of considerable substance and thus in a solid portion of the anchor element with a great wall thickness.  
         [0052]     This embodiment further affords the advantage that the suture holder and the course of a central bore in the anchor element can be kept spatially separate from one another.  
         [0053]     This allows the depth of the central bore to be adapted to differently designed anchor elements. This ensures an optimal depth of insertion of a tool into the anchor element.  
         [0054]     It is additionally advantageous that a suture received in the proximal portion of the anchor element can be guided directly with its thread ends in the proximal direction toward the tool. The suture is thus guided away from the direct operating site and toward the tool, and interference with the operation is avoided. The suture received in the channel cannot fall out to the sides.  
         [0055]     In another embodiment, the channel is widened in a funnel shape at the proximal end face.  
         [0056]     This measure has the advantage of making it easier to insert the at least one suture into the channel of the anchor element.  
         [0057]     In another embodiment, the anchor element has several U-shaped channels.  
         [0058]     This measure has the advantage that several sutures can be received simultaneously in the anchor element. In this way, forces that arise are distributed between different sutures and positions in the anchor element and are thereby reduced. The anchor element is exposed to less material stress than is caused by a single substantial force that occurs locally.  
         [0059]     Moreover, the increased number of suture ends allows an operating surgeon a more varied approach when securing a tendon or a ligament.  
         [0060]     In another embodiment, the anchor element has two U-shaped channels.  
         [0061]     This measure has the advantage that two channels in the anchor element represent a very good compromise between the aforementioned advantages and the material removed from the anchor element.  
         [0062]     In another embodiment, the two U-shaped channels are arranged diametrically in the anchor element.  
         [0063]     This measure has the advantage that securing the anchor element on the tool with the aid of the sutures threaded into the channels takes place in a uniform manner. Forces that act on the anchor element during introduction are in this way distributed uniformly.  
         [0064]     In addition, the anchor element and also the sutures are thus secured captive on the tool during introduction.  
         [0065]     This measure also has the advantage that tensile loads acting on the inserted sutures are conveyed to the bone at opposite parts of the anchor element that has been introduced. This ensures uniform loading of the anchor element in a loading situation in the bone. Damage to the anchor element by locally delimited peak forces is thus ruled out.  
         [0066]     The object is achieved, in another and third alternative, by an anchor element having an elongated body, said body having a central bore for receiving a tool for introducing said anchor element into said bone, said body having a proximal end section surrounding said central bore, said end section being designed as a jacket of considerable substance, wherein at least one suture eyelet member projects in a proximal direction from said jacket of considerable substance, said suture eyelet member having an opening, said at least one suture is received in said eyelet member opening.  
         [0067]     These measures have the advantage that a suture placed in the suture eyelet takes the forces acting on it and conveys them uniformly to the jacket of considerable substance of the anchor element.  
         [0068]     A suture holder in the form of a suture eyelet of this design provides the suture with a suitably large contact surface. This contact surface extends within a part of the jacket of thick material of the anchor element. In this way, the suture takes the forces acting on it and conveys them to a solid portion of the anchor element.  
         [0069]     The more elongate the suture eyelet in which the suture is received in the anchor element, the greater also is the contact surface of the suture. In this way, the forces acting on the suture are conveyed uniformly to the anchor element across a greater surface area, and locally concentrated forces are avoided. This protects the suture eyelet from being torn out or broken off.  
         [0070]     This embodiment also has the advantage that the suture holder and the course of a central bore in the anchor element can be kept spatially separate from one another.  
         [0071]     This allows the depth of the central bore to be adapted to different designs of anchor elements. In this way, an optimal depth of introduction of a tool into the anchor element is ensured. A tool pushed into the anchor element ensures reliable insertion of the anchor element into the bone.  
         [0072]     In another embodiment, the suture eyelet member extends along a secant in the area of the jacket of considerable substance.  
         [0073]     This measure has the advantage that the suture eyelet member extends across a long area and thus offers an inserted suture a suitably large surface area of contact. In this way, the forces acting on the suture are conveyed uniformly to the anchor element across a greater surface area, and locally concentrated forces are avoided.  
         [0074]     The danger of the suture eyelet member being torn out is therefore minimized by the greater distribution of the forces in the suture eyelet.  
         [0075]     In another embodiment, the at least one opening in the suture eyelet member is beveled.  
         [0076]     This measure has the advantage of preventing fraying of the suture which, in accordance with its function, extends upward at the opening of the suture eyelet member. Damage or severing of the suture is thereby avoided.  
         [0077]     In another embodiment, the at least one opening in the suture eyelet member has a curved course.  
         [0078]     This measure has the advantage that the suture in a curved suture eyelet member is in contact uniformly along its entire course. This avoids individual, local contact points for the suture. In this way, tensile forces that arise are conveyed uniformly to the anchor element, and stressing of the anchor element is further reduced.  
         [0079]     In another embodiment, the curved course is U-shaped.  
         [0080]     This measure has the advantage that, when exposed to tensile stress, the suture arranged in a suture eyelet member extending in a U-shaped curve bears tightly and uniformly against a wall of the suture eyelet member. This permits a uniform distribution of the tensile force across the suture eyelet member. As has already been described, this represents an ideal case of optimal distribution of force to the anchor element.  
         [0081]     In this way, the forces acting on the suture eyelet member are conveyed uniformly to the anchor element across a greater surface area, and locally concentrated forces are avoided. This protects the suture eyelet member from being torn out or broken away from the jacked of considerable substance.  
         [0082]     In another embodiment, the anchor element has several suture eyelet members.  
         [0083]     This measure has the advantage that the anchor element can receive several sutures through several suture eyelet members. Forces that arise are reduced into portions across a plurality of sutures and are in this way conveyed uniformly to different locations of the anchor element.  
         [0084]     The anchor element experiences less material stress than is caused by a single substantial force that occurs locally.  
         [0085]     Moreover, the increased number of suture ends allows an operating surgeon a more varied approach when securing a tendon or a ligament.  
         [0086]     In another embodiment, the anchor element has two suture eyelet members.  
         [0087]     This measure has the advantage of affording an optimal compromise between the number of suture eyelet members and the stress acting on the jacket of considerable substance.  
         [0088]     In another embodiment, the two suture eyelet members are arranged diametrically in the anchor element.  
         [0089]     This measure has the advantage that the openings of the suture eyelets are distributed uniformly across the proximal portion of the jacket. Securing the anchor element to the tool with the aid of the sutures threaded into the slits therefore also takes place with uniform orientation. In this way, forces that act on the anchor element during introduction are uniformly distributed.  
         [0090]     It will be appreciated that the aforementioned features and the features still to be explained below can be used not only in the stated combination but also in other combinations or singly, without departing from the scope of the present invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0091]     The invention, in its three alternative forms, is described and explained in more detail below on the basis of selected illustrative embodiments and with reference to the attached drawings, in which:  
         [0092]      FIG. 1  shows a side view of a first alternative of an anchor element,  
         [0093]      FIG. 2  shows a section along the line II-II in  FIG. 1 ,  
         [0094]      FIG. 3  shows a side view of second alternative of an anchor element,  
         [0095]      FIG. 4  shows a section along the line IV-IV in  FIG. 3 ,  
         [0096]      FIG. 5  shows a side view of third alternative of an anchor element,  
         [0097]      FIG. 6  shows a view of the proximal end of the anchor element from  FIG. 5 ,  
         [0098]      FIG. 7  shows a side view of the anchor element from  FIG. 1  and of a distal end of a tool which is intended to be inserted from proximal to distal into the anchor element,  
         [0099]      FIG. 8  shows the assembly of anchor element and tool from  FIG. 7  joined together, with inserted sutures, and  
         [0100]      FIG. 9  shows a situation when introducing the assembly. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0101]     Surgical suture anchor elements according to the invention are shown in each of  FIGS. 1, 3  and  5  and are respectively designated in their entirety by reference numbers  10 ,  10 ′ and  10 ″.  
         [0102]     The anchor element  10  in  FIGS. 1 and 2  has an elongate, approximately cylindrical body  16  in its proximal portion  20 . This cylindrical body  16  merges into a taper  18  in a distal portion  30 .  
         [0103]     A self-tapping thread  42  extends in the distal direction along the taper  18 . This self-tapping thread  42  runs out in a tip  43 .  
         [0104]     In its proximal portion  20 , the anchor element  10  has a central bore  14 . This central bore  14  is designed as a blind hole.  
         [0105]     This central bore  14  extends axially along the central longitudinal axis  19  of the anchor element  10 . It reaches deep into the anchor element  10  and, as is shown in  FIG. 2 , has a hexagonal cross section. The latter serves to receive a tool in a rotationally fixed manner.  
         [0106]     The central bore  14  is surrounded about its circumference by a jacket  22  of considerable substance. The jacket  22  is a part of the anchor element  10  with most and thick material compared to the other parts of the anchor element  10 .  
         [0107]     Two slits  24  and  24 ′ are formed in this jacket  22  of thick material. They extend transversely with respect to the central longitudinal axis  19  of the anchor element  10 . In doing so, they extend equally in the circumferential direction of the jacket  22  of thick material.  
         [0108]     The slits  24  and  24 ′ each have flanks  32  and  32 ′, respectively. These flanks  32 ,  32 ′ extend in parallel into the anchor element  10  and join together at a rounded base  34 .  
         [0109]     The parallel flanks  32 ,  32 ′ of each slit  24 ,  24 ′ open laterally outward onto a radial outer face  36 .  
         [0110]     The flanks  32 ,  32 ′ and also the rounded base  34  are beveled at their transition to the radial outer face  36 .  
         [0111]     To securely receive the suture, the flanks  32 ,  32 ′ of the slits  24 ,  24 ′ are inclined in the distal direction, as seen radially outward from the base  34 .  
         [0112]     It will be seen clearly that a suture  12  which is inserted into the slits  24 ,  24 ′ and is held taut cannot escape distally out of the slit  24 ,  24 ′.  
         [0113]      FIG. 2  illustrates how the central bore  14  is surrounded about its circumference by the jacket  22  of considerable substance. This jacket  22  of thick material has its material reduced only by the slits  24 ,  24 ′.  
         [0114]     It will also be seen that the central bore  14  and the slits  24 ,  24 ′ are spatially separated. This means that the tool  44  is received in a manner unimpeded by a suture holder in the anchor element  10 .  
         [0115]     The anchor element  10 ′ shown in  FIG. 3  also has an elongate, approximately cylindrical body in its proximal portion  20 . The cylindrical body merges into a taper in a distal portion  30 .  
         [0116]     A self-tapping thread  42  extends in the distal direction along the taper  18 . This self-tapping thread  42  runs out in a tip  43 .  
         [0117]     Along its entire length, the tip  43  also has a notch which supports the self-tapping thread  42  during screwing-in.  
         [0118]     The anchor element  10 ′ also has a central bore  14  in its proximal portion  20 , as is shown in  FIG. 3 . This central bore  14  is likewise designed as a blind hole.  
         [0119]     As has already been described, the central bore  14  extends axially along the central longitudinal axis of the anchor element  10 ′. It again reaches deep into the anchor element  10 ′ and, as is shown in  FIG. 4 , has a hexagonal cross section. The latter serves to receive a tool in a rotationally fixed manner.  
         [0120]     In this case too, the central bore  14  is surrounded about its circumference by a jacket  22  of considerable substance.  
         [0121]     The jacket  22  of thick material has two openings at the proximal end face. They are each formed as a U-shaped channel  26  and  26 ′ which opens out in the proximal direction.  
         [0122]     For easier introduction of a suture  12 , these channels  26 ,  26 ′ are widened in a funnel shape at the proximal end.  
         [0123]     The cross section in  FIG. 4  illustrates how the central bore  14  is surrounded about its circumference by the jacket  22  of thick material. This jacket  22  of thick material has its material thickness reduced only by the channels  26 ,  26 ′.  
         [0124]     It will also be seen that the central bore  14  is formed in the anchor element  10 ′ separate from the channels  26 ,  26 ′. This means that the tool is received in a manner unimpeded by a suture holder in the anchor element  10 ′.  
         [0125]     When the anchor element  10 ′ is produced as an injection-molded part, the injection mold can contain, in the area of the channels  26  and  26 ′, a U-shaped wire which has the form of the channels  26  and  26 ′ and which is subsequently removed from the injection-molded part.  
         [0126]     When the anchor element  10 ′ is produced as a metal part, it can be suitably preshaped as a metal-powder blank and then sintered.  
         [0127]     Another anchor element  10 ″ is shown in  FIG. 5 .  
         [0128]     This anchor element  10 ″ also has an elongate, approximately cylindrical body in its proximal portion  20 . The cylindrical body merges into a taper in a distal portion  30 .  
         [0129]     In this case too, a self-tapping thread  42  extends in the distal direction along the taper. This self-tapping thread  42  also runs out in a tip  43 .  
         [0130]     Along its entire length, the tip  43  also has a notch which supports the self-tapping thread  42  during screwing-in.  
         [0131]     The anchor element  10 ″ also has a central bore  14  in its proximal portion  20 , as is shown in  FIG. 5 . This central bore  14  is likewise designed as a blind hole.  
         [0132]     As has already been described, the central bore  14  extends axially along the central longitudinal axis of the anchor element  10 ″. It reaches deep into the anchor element  10 ″ and, as is shown in  FIG. 6 , has a hexagonal cross section. The latter serves to receive a tool  44  in a rotationally fixed manner.  
         [0133]     In this case too, in the proximal portion  20 , the central bore  14  is surrounded about its circumference by a jacket  22  of considerable substance. This jacket  22  of thick material also gives this anchor element  10 ″ its outwardly cylindrical shape.  
         [0134]     Two suture eyelet members  28  and  28 ′ project in the proximal direction from this jacket  22  of thick material. These suture eyelet members  28  and  28 ′ have beveled openings.  
         [0135]     The suture eyelet members  28 ,  28 ′ extend along secants of the circular end face on the jacket  22  of thick material. A suture  12 ,  12 ′ is threaded respectively into these suture eyelet members  28 ,  28 ′. The taut sutures  12 ,  12 ′ point with their suture ends in the proximal direction. This is illustrated in  FIGS. 5 and 6 .  
         [0136]      FIG. 6  again illustrates how, in this case too, the central bore  14  is surrounded about its circumference by the jacket  22  of thick material. As is shown here, however, this jacket  22  of thick material is completely unaffected by a material reduction.  
         [0137]     It will also be seen here that the central bore  14  is formed in the anchor element  10 ″ separate from the suture eyelet members  28 ,  28 ′. This means that, in this case too, the tool  44  is received in a manner unimpeded by a suture holder in the anchor element  10 ″.  
         [0138]     As can be seen from  FIGS. 1, 3  and  5 , the respective anchor element  10 ,  10 ′,  10 ″ has specific openings in the form of slits, channels and suture eyelets. Sutures  12 ,  12 ′ can be received in these in such a way that both free ends of the suture extend away from the anchor element  10 ,  10 ′,  10 ″ in the proximal direction. The sutures  12 ,  12 ′ are in each case arranged diametrically in the anchor element  10 ,  10 ′,  10 ″.  
         [0139]     It will be seen from  FIG. 7  that a tool  44  can be pushed from proximal to distal into the central bore  14  of the anchor element  10 .  
         [0140]     The tool  44  has a hexagonal distal end  46 . The cross section of the distal end  46  corresponds to the cross section of the central bore  14 . The distal end  46  can thus be pushed into the central bore  14  as indicated by an arrow  54  in  FIG. 7 .  
         [0141]     The distal end  46  is thus received in a positive and rotationally fixed manner in the anchor element  10 . The depth of insertion of the distal end  46  is adapted to the central bore  14 . Obstruction by transversely extending sutures  12 ,  12 ′ is avoided in this arrangement.  
         [0142]     As will also be seen from  FIG. 7 , pins  48 ,  48 ′ protrude radially from the tool  44 . These pins  48 ,  48 ′ are arranged diametrically on the tool  44  and serve for the threading and fixing of the sutures  12 ,  12 ′.  
         [0143]     A tool  44  pushed fully into the anchor element  10  is shown in  FIG. 8 .  
         [0144]     A suture  12 ,  12 ′ is now inserted into the respective slit  24 ,  24 ′, held taut, and fixed over the pins  48 ,  48 ′. In this way, the anchor element  10  is secured against slipping or loss during introduction.  
         [0145]     This is supported by the hexagonal cross section of the central bore  14  of the respective anchor element  10 . By this means, the tool  44  is received in a positive and rotationally fixed manner in the anchor element  10 .  
         [0146]     A complete tool  50  composed of anchor element  10 , sutures  12 ,  12 ′ and tool  44  and used for introduction of an anchor element is shown in  FIG. 8 .  
         [0147]     To introduce the anchor element  10 , the complete tool  50 , as shown in  FIG. 9 , is now initially placed with the tip  43  of the anchor element  10  at a certain position on the bone, for example a shoulder bone  60 . To be able to turn the anchor element  10  into the shoulder bone  60 , the tool  44  has a grip  56  at the proximal end. The turning of the tool  44  is indicated by an arrow  57  in  FIG. 9 . The self-tapping thread  42  bores its own way into the bone  60 . The tip  43  supports the self-tapping thread  42 .  
         [0148]     Alternatively, the anchor element  10  can also at first be driven in linearly by a hammer blow to the tool  44 , as is indicated by an arrow  59 . Then, by turning the complete tool  50 , the anchor element  10  is turned into the bone  60 , this procedure being supported by the thread  42 . During this procedure, the suture  12 ,  12 ′ is secured against displacement or twisting, since it is fixed on the pins  48 ,  48 ′.  
         [0149]     After the anchor element  10  has been turned to the full extent into the shoulder bone  60 , the tool  44  is withdrawn in the proximal direction. In doing this, the anchor element  10  remains in the bone  60 . Using the protruding ends of the suture  12 ,  12 ′, it is now possible to fix a tendon  62  that has been torn from the shoulder bone  60 .  
         [0150]     This procedure can equally be carried out with the anchor elements  10 ′ and  10 ″.  
         [0151]     If it is made of absorbable material, an anchor element  10 ,  10 ′,  10 ″ that has been introduced in this way so as to bear tightly on the bone substance can be gradually replaced by bone substance, such that the tendon  62  is then once again fixed in a manner true to nature.