Device for inserting an anchoring element and a suture thread into a bone

A device serves to insert an anchoring element and a suture thread into a bone to attach a tendon or a ligament without drilling a hole into the bone. The device comprises an anchoring element, having a proximal end, a distal end, and a longitudinal axis and further a continuous channel, and a tool for inserting the anchoring element and the suture thread, having a longitudinal axis, a distal end section and a further section being designed in such a way that it can be introduced into the anchoring element from the proximal end to the distal end. The tool can be inserted into the continuous channel of the anchoring element in such a way that the distal end section of the tool projects distally beyond the anchoring element, wherein the projecting distal end section is designed as a stable driving head. The anchoring element further has an external thread.

BACKGROUND OF THE INVENTION

The invention relates to a device for inserting an anchoring element and a suture thread into a bone to attach a tendon or a ligament without drilling a hole into the bone.

Anchoring elements of this kind are anchored in a bone together with a suture thread, and a torn tendon or ligament is reattached to the bone with the suture thread.

One of the main applications for such anchoring elements is the attachment of torn tendons in the shoulder area.

Two types of procedure have become established in this technology.

In the first type of procedure, a channel is drilled into the bone, and the anchoring element with the suture thread is introduced into this predrilled channel. For this, the anchoring element is mounted on a tool and driven into the drill hole with this tool. Once the anchoring element is in place, the tool is removed, and the tendon is attached using the ends of the suture thread which project from the drill hole. The outside of the anchoring element has hook-like or barb-like projections to anchor the anchoring element in the drill hole.

U.S. Pat. No. 5,690,676 describes a design in which the anchoring element has a continuous channel by means of which a guide wire can be pushed through the anchoring element such that a distal end section of the guide wire projects beyond the anchoring element. This projecting section serves as an aid for targeting and inserting, particularly in cases where the anchoring elements are small or the drill holes are very small. This means the wire is inserted into the drill hole in the bone, and the anchoring element is then advanced along the wire and into the drill hole. The wire is then withdrawn, the tool attached, and the previously described driving in operation effected.

With this technology it is absolutely essential to drill a hole in the bone beforehand.

U.S. Pat. No. 4,632,100 describes a device for inserting an anchoring element which can be used without drilling a hole first.

Here, the distal tip of the anchoring element itself is designed as a driving head. For this, the anchoring element must be very sturdy and, in particular, must be made of metal. In addition, the outside of the anchoring element has an external thread so that once the anchoring element has been knocked in it can be anchored in the bone with a turning movement by means of the external thread. A tool is attached to the proximal end of the anchoring element for this operation. Here too a suture thread can be introduced at the same time.

The drawback of this design is that the anchoring element needs to be very sturdy, very complex, and, in particular, has to be made of metal and remains in the body as a metallic foreign body.

Knock-in anchors of this kind cannot be used for osteoporotic bones. Furthermore, attempts are being made to use absorbable materials which can gradually be replaced by endogenous bone tissue. However, since absorbable materials do not have sufficient mechanical stability, it is not possible to use knock-in anchors made of such materials.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to create a device of the type mentioned at the start which does not require the drilling of a hole but also allows the anchoring element to be constructed of absorbable materials.

In accordance with an aspect of the invention a device for inserting an anchoring element and a suture thread into a bone to attach a tendon or ligament without drilling a hole in the bone is provided, comprising an anchoring element having a proximal end, a distal end and a longitudinal axis and further having a continuous channel and an external thread. The device further comprises a tool for inserting the anchoring element and the suture thread, having a longitudinal axis, a distal end section and a further section being designed in such a way that it can be introduced into the anchoring element from the proximal end to the distal end, the tool being able to be inserted into the continuous channel of the anchoring element in such a way that the distal end section of the tool projects distally beyond the anchoring element, the projecting distal end section being designed as a stable driving head.

The fact that the section of the tool which projects distally beyond the anchoring element is designed as a stable driving head means that it is now possible to drive this assembly in like a knock-in anchor without drilling a hole first. However, it is not the distal tip of the anchoring element that is driven in, but only the distal section of the tool that projects beyond the anchoring element. This must have adequate strength and rigidity and must also be made of metallic materials.

The provision of the external thread on the outside of the anchoring element means that, once the distal tip of the tool has been knocked in, the anchoring element/tool assembly can be turned and the anchoring element can be screwed into the opening created by the knocking-in and can be secured in place by means of the external thread. After this operation the tool is removed and the anchoring element is left firmly anchored in the bone without there having been a need to drill a hole first and without the anchoring element having to be constructed of stable and, in particular, metallic materials.

In a further embodiment of the invention the tool is accommodated in the anchoring element in a rotationally locked manner.

The advantage of this arrangement is that this rotational locking makes the turning movement effected when screwing in the thread of the anchoring element easy to perform.

In a further embodiment of the invention the tool has a tip at a distal end section.

The advantage of this arrangement is firstly that the surgeon is able to precisely target the contact site or knock-in point with the aid of the tip and furthermore that the distal end section of the tool formed as a stable driving head can be driven in gently.

In a further embodiment of the invention the anchoring element comprises a distal taper.

The advantage of this arrangement is that the anchoring element, sliding smoothly over this taper, can be driven into the bone during the initial driving in operation.

In a further embodiment of the invention the taper is designed in such a way that it is continued by the tip of the tool.

This arrangement has the particular advantage that there is a smooth transition from the distal end of the anchoring element to the tip of the tool projecting beyond the anchoring element, with the result that driving in operation can be carried out in a particularly nondisruptive manner.

In an embodiment of the invention the external thread of the anchoring element extends over roughly the rear, proximal half of the anchoring element.

The advantage of this arrangement is that the anchoring element can first be driven or knocked into the bone to a certain extent in a linear driving in operation and that the external thread only then screws into the bone.

In a further embodiment of the invention the external thread of the anchoring element extends over the entire length of the anchoring element.

The advantage of this arrangement is that in the case of particularly porous bones, when anchoring over the whole of the outside of the anchoring element is necessary, this can be effected via this external thread which extends over the entire body.

In a further embodiment of the invention the section of the tool that can be inserted into the anchoring element has a cross-sectional profile which is roughly the shape of a three-pointed star.

The advantage of this arrangement is that this geometry makes it possible to achieve a rotationally locked connection with a very large area of contact with the anchoring element, such that even high torque does not cause the anchoring element to deform or shear off.

In a further embodiment of the invention the section of the tool which is inserted in the anchoring element has a cross-sectional profile which is roughly the shape of a figure eight.

The advantage of this arrangement is that this too allows the creation of a rotationally locked connection with a relatively large area of contact and that in the middle of the eight there is a space for the suture thread on both sides.

In a further embodiment of the invention the anchoring element has a continuous opening to accommodate the suture thread, this opening running transverse to the longitudinal axis of the anchoring element.

The advantage of this known arrangement is that the suture thread passes once, transversely, right through the anchoring element, this providing the appropriate support by which the suture thread can then be firmly connected to the tendon.

In a further embodiment of the invention the position of the end point of the tip of the tool is radially offset relative to the central longitudinal axis of the tool.

As mentioned earlier, the suture thread is passed once, transversely, right through the anchoring element, i.e. diametrically. The lateral offset of the tip prevents the tip from hitting the suture thread—it pushes past the suture thread because of the lateral offset—and prevents it from getting caught or stuck on the suture thread.

In a further embodiment of the invention the continuous opening passes into grooves which run axially, in a proximal direction, along the outside of the anchoring element and which serve to accommodate the suture thread.

The advantage of this arrangement, which is also known per se, is that the suture thread can be guided in a proximal direction along the outside. The grooves extend through the thread, so that the suture thread is not damaged when the anchoring element is driven in beyond the thread section.

In a further embodiment of the invention the tool has grooves which continue the grooves of the anchoring element in a proximal direction and which serve to accommodate the suture thread axially.

The advantage of this arrangement is that the orientation of the grooves allows the suture thread to be guided in a proximal direction, along the outside of the anchoring element/tool assembly, on both sides.

In a further embodiment of the invention the tool has a catching slit in the section which is inserted into the anchoring element to accommodate the suture thread.

The advantage of this arrangement is that the suture thread inserted in the anchoring element is captured by the catching slit and held in the tool in a defined way.

In a further embodiment of the invention the catching slit opens to one side of the tool.

The advantage of this arrangement is that, when the tool is pushed in, the suture thread in the continuous opening in the anchoring element is moved to one side—specifically by the laterally offset tip—and then automatically threaded, or slid, into the catching slit.

In a further embodiment of the invention one end of the catching slit of the tool comes to rest at the level of the continuous opening of the anchoring element when the tool has been introduced into the anchoring element.

The advantage of this arrangement is firstly that the tool brings the suture thread into a precisely predetermined position in the anchoring element, i.e. in exact alignment with the lateral openings by which the suture thread passes through the anchoring element.

At the same time this construction also allows the possibility of first inserting the tool into the anchoring element and then, by aligning the opening and the end of the catching slit, of threading the suture thread through the assembly.

In a further embodiment of the invention the tool has a shoulder which comes to rest on a corresponding shoulder on the anchoring element.

The advantage of this arrangement is that the depth of insertion of the tool into the anchoring element is precisely limited, namely when the opposing shoulders are in contact with one another.

It will be appreciated that the features mentioned above and those still to be explained below can be used not only in the described combinations but also in other combinations or on their own without departing from the scope of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 to 3show an anchoring element which as a whole is designated with the reference number10.

The anchoring element10has a roughly cylindrical body12, which distally changes into a taper14.

The taper14is made up of three segments16,17, and18which are uniformly distributed around the circumference.

The outside of the cylindrical body12has a thread20.

At the point where the cylindrical body12joins the taper14, there is a continuous transverse opening22.

Extending in a proximal direction from the opening22and lying diametrically opposite each other are grooves24and25, which extend right through the thread20and emerge at the proximal end.

AsFIG. 2shows, a suture thread28can be pushed through the opening22and inserted in the grooves24and25such that the two free ends of the suture thread28extend away from the anchoring element10in a proximal direction. The suture thread runs diametrically through the anchoring element10.

The sectional illustration inFIG. 3shows that extending through the middle of the anchoring element10there is a continuous channel30, which in the area of the cylindrical body12has a cross-section32with the shape of a three-pointed star.

Proximally, the channel30terminates in a sloped shoulder34.

AsFIG. 4shows, to insert the anchoring element10, a tool40is inserted from the proximal to the distal position.

Distally, the tool40has a roughly pyramid-shaped tip42, which is relatively sturdy. The external end of the tip42is laterally offset relative to the central longitudinal axis44of the tool40and thus also laterally offset relative to the central longitudinal axis36of the anchoring element10. The tip42changes into a section48with a cross-sectional profile which likewise has the shape of a three-pointed star.

In other words, section48can be inserted in the cross-section32of the channel30of the anchoring element10in a form-fitting and rotationally locked manner.

AsFIG. 4shows, this section48has a catching slit50which opens to one side, namely the side opposite to the direction of the offset of the tip42. One end52of the catching slit50comes to rest at the level of the continuous opening22of the anchoring element10when the tool40is inserted into the anchoring element10, as described below.

The section48changes into a rod-shaped section60of the tool40, via a shoulder54.

The shoulder54is formed in such a way that it can come to rest fittingly against the shoulder34at the proximal end of the anchoring element10, the depth of insertion being accordingly limited or determined.

FIG. 4also shows that, cut into the outside of the rod-shaped section60, there are grooves56, which extend the grooves24and25found on the anchoring element10. Projecting radially from each groove56is a pin58on which to thread or attach the suture thread28.

AsFIG. 6shows, the rod-shaped section60changes into a handle62, the end of which has a strike head64.

To insert the anchoring element10, the suture thread28is first threaded into the anchoring element10, as shown inFIG. 2.

The tool40is then inserted, as shown inFIG. 4. Due to the lateral offset of the tip42, the tip42pushes past the section of suture thread28that runs transversely through the anchoring element10, and the suture thread28is automatically guided into the catching slit50as the tool40is advanced.

Once the tool40is fully inserted in the anchoring element10, as shown inFIG. 5, the suture thread28can again be placed tightly and precisely into the grooves24and25or their extensions56on the tool and be attached via the pins58,58′.

A distal end section46of the tool40projects distally beyond the anchoring element10. The taper14or the three segments16,17,18fit snugly against the contour of this distal end section46.

The tool40is made of a metallic material; the anchoring element10is made of an absorbable material.

To insert the anchoring element10, the tip42of the projecting distal end section46of the device80according to the invention is first brought into contact with a certain site on the bone, e.g. a shoulder bone68, as shown inFIG. 6, and the device80, i.e. the assembly of the anchoring element10and the tool40, is first driven in, linearly, as indicated by the arrow65, using a striking tool.

This driving in operation is continued until the anchoring element10has been driven in so far that the distal end section46and the taper14have been driven in.

Now, by turning the assembly in the manner shown by an arrow63inFIG. 6, the assembly is screwed into the bone68with the help of the thread20. The suture thread28is protected from displacement or twisting during this operation, since it is contained within the grooves24,25and56.

Once the anchoring element10has been completely screwed into the shoulder bone68, the tool40is withdrawn in a proximal direction, leaving the anchoring element10anchored in the bone.

A tendon70, which has become detached from the shoulder bone68, can be reattached with the projecting ends of the suture thread28.

Since no hole has had to be drilled in68, the anchoring element10is in close contact with the bone tissue. Since it is made of absorbable material, it is gradually replaced by bone tissue, resulting in a reattachment of the tendon70which resembles the natural state.