GB2288737A

GB2288737A - Suture anchor

Info

Publication number: GB2288737A
Application number: GB9407660A
Authority: GB
Inventors: Derek Redvers Cooper; George John James Cremore; Andrew Jonathon Carr
Original assignee: Corin Medical Ltd
Current assignee: Corin Medical Ltd
Priority date: 1994-04-18
Filing date: 1994-04-18
Publication date: 1995-11-01
Also published as: GB9407660D0

Abstract

A suture anchor especially suitable for repairing tears of the rotator cuff tendons is disclosed. The anchor 10 comprises screw-receiving means 16, 18a for rotatably receiving a bone screw, suture receiving means 24 for receiving at least one suture and anchoring means 22 for preventing relative rotation between the suture anchor and a bone into which the bone screw is screwed. During insertion into the bone, and whilst sutures holding the tendon are in the receiving channels 24, the anchor can be rotated on the screw with respect to the bone to allow the orientation of the anchor to be adjusted. The screw is then further inserted into the bone to achieve a firm fixing. The anchoring means provide a broad area of anchorage and the anchor does not require a specialised tool to fix it in position. <IMAGE>

Description

SUTURE ANCHOR The invention relates to a suture anchor, particularly but not exclusively to a suture anchor for repairing tears of the rotator cuff tendons.

Tears of the rotator cuff tendons near their insertion are a common traumatic condition. When performing rotator cuff repairs, surgeons have traditionally sought to excise all non-viable tissue and re-attach the tendon to the appropriate bone surface, Creation of an enclosure is also advantageous. A number of techniques and devices have been developed to enhance the surgeons ability to successfully re-attach torn tendons to the appropriate bone surface. Traditionally, sutures have been used to secure the tendons through drilled holes in the bone. The suture is attached to the tendon in question and then pulled through the drilled hole and secured so that the tendon comes into contact with the bone surface and a natural repair will eventually take place. However, this technique requires accurate placement of the sutures and careful alignment, the outcome also being highly dependent upon the quality of the bone to which the tendon is to be attached.

Techniques have also been suggested wherein the tendon in question is effectively pinned directly to the bone surface but these techniques have proved insufficient because of the inadequacy of the bone surface tissue to which the fixing devices must be secured.

Alternative techniques involve making full use of soft tissue anchors which consist of small metallic fixing plugs, often incoporating anchoring pegs or barbs which prevent the plugs from being withdrawn from the bone tissue into which they are inserted. An example of this type of anchoring device is the MITEK GII anchor produced by Mitek Surgical Products Inc. However, this type of anchor is very small in dimensions and therefore secure fixation is highly dependent upon the quality of a very small localised area of bone. Furthermore, this type of anchor is suitable for anchoring only a single suture and therefore a considerable number of anchors must be utilised in order to repair a sizable tear in the appropriate soft tissue. Further disadvantages of this type of anchoring device are that, in virtually all cases, specifically adapted tools are required to place the anchors and the anchors are not readily removable if required.

It is an object of the invention to provide an improved, reliable suture anchor suitable for repairing torn tendons. A further object of the invention is to provide a suture anchor capable of providing an improved attachment between the torn tendon and the appropriate bone surface.

The invention provides a suture anchor as set out claim 1. The invention also provides a fixing device as set out in claim 13 and a method of anchoring at least one suture as set out in claims 15 and 16. Advantageous features of the invention are set out in the subsidiary claims.

The fact that the attachment of the suture anchor is by means of a standard bone screw means that no new techniques or tools are required to fix the suture anchor in position. Furthermore, the fact that the suture anchor is, in use, rotatably mounted on the bone screw means that a suitable anchoring position for the bone screw can be selected and the suture anchor can then be rotated with respect to the bone and the screw to provide the most appropriate orientation. The screw is then inserted further into the bone so that a firm fixing is achieved.

A further advantage of the suture anchor according to the invention is that the anchor itself is relatively broad in area and therefore will not be dependent upon the quality of localised areas of bone tissue. This greatly improves the securement of the suture anchor to the bone. Furthermore, the suture anchor is easily and efficiently fixed with a minimum of manipulation and drilling. It also allows the surgeon to achieve an appropriate tension in the suture without any significant amount of guesswork.

An embodiment of the invention will now be described with reference to the accompanying drawings wherein: Figure 1 is a plan view of a suture anchor according to the invention; and Figure 2 is a side view of the suture anchor of Figure 1.

The suture anchor 10 shown in Figures 1 and 2 consists essentially of a substantially tubular barrel 12 and a head portion 14. The barrel 12 is substantially cylindrical having a central aperture 16 running therethrough. Both ends of the aperture 16 are countersunk at 18a and 18b.

The head portion 14 consists essentially of an upper flange 20 from which depend four equispaced prongs 22.

Each prong 22 carries a sharpened edge 22a at the end thereof remote from the flange 20.

The arrangement of the barrel 12, the flange 20 and the prongs 22 is such that a suture-receiving channel 24 is formed beneath the flange 20. The suture-receiving channel 24 can be accessed between the prongs 22. Also, the suture anchor 10 is manufactured from a bioresorbable or bioabsorbable material.

The dimensions of the suture anchor illustrated in Figures 1 and 2 are such that a standard bone screw can be introduced into the aperture 16. The head of the bone screw is accommodated by the countersunk end 18a of the aperture 16 so that the head of the screw does not project above the upper surface of the flange 14. The combination of the suture anchor 10 and a bone screw (not illustrated) forms a fixing device according to claims 13 and 14. The bone screw can, if desired, also be formed from a bioresorbable or bioabsorbable material.

The suture anchor illustrated Figure 1 can be utilised in the following manner. Firstly, a bone screw is introduced into the aperture 16 with the head of the screw accommodated by the countersunk end 18a of the aperture. With the suture anchor rotatably held on the bone screw, the bone screw is then screwed into the appropriate area of the bone to which a tendon is to be attached. The bone screw is screwed into the bone to a sufficient depth for the lower edges 22a of the prongs 22 to be close to but not touching the surface of the bone. Preferably, the lower edges 22a of the prongs 22 remain spaced from the surface of the bone by at least the width of a standard suture. Appropriate sutures are then attached to the tendon in question and the sutures are then introduced into the suture-receiving channel 24 by slipping the sutures underneath the lower edges 22a of the prongs 22. The sutures can be introduced in a manner appropriate to the orientation of the tendon with respect to the point of anchoring of the bone screw by utilising different entry and exit ports between the prongs 22. Furthermore, the suture anchor 10 can be rotated with respect to the bone screw in order to adjust the orientation if desired. Furthermore, several sutures can be introduced into the suture-receiving channel 24 if appropriate. In each case, the suture will be effectively wrapped around the outer surface of the barrel 12 which provides an anchor with no sharp corners or surfaces which may cause wear of the sutures.

The sutures can be tied off and anchored in any known manner. Keeping the appropriate orientation of the suture anchor 10 with respect to the bone screw, the bone screw is then screwed further into the appropriate bone until the lower edges 22a of the prongs 22 bite into the upper surface of the bone to which the tendon is to be attached. Once the prongs 22 are securely embedded in the bone, the suture anchor 10 cannot subsequently rotate with respect to the bone and thereby a secure anchorage point is provided. Also, the suture anchor 10 effectively clamps the suture or sutures to the surface of the bone. Further suture anchors are then located and secured as necessary to secure the soft tissue requiring repair.

The advantage of this type of suture anchor lies primarily in the fact that the anchorage of suture relies completely on a well tried and tested form of anchoring, ie. the bone screw. Virtually all surgeons are familiar with the insertion of bone screws and have access to the tools required to carry out the appropriate surgical techniques. Specialised or adapted tools are not required to make use of the suture anchor described above. A further advantage is that, because of the fact that a plurality of depending projections are provided around the periphery of the flange 14, the suture anchor provides a broad area of anchorage which does not rely on the quality of the bone in any one particular localised area. If, for example, the quality of the bone in the area of one prong 22 is insufficient to prevent rotation of the suture anchor 10, then there are further prongs (three in this embodiment) which will each be equally capable of providing the necessary anchoring. This broad area of anchorage also reduces the probability of the suture anchor migrating away from the originally intended anchorage position which can occur with some smaller anchorage devices.

It is advantageous if the sutures attaching the tendon to the bone are spaced apart from one another.

This is achievable to a certain extent by introducing the sutures into the suture-receiving channel 44 at different points around the circumference of the barrel 12. In effect, a single suture anchor as described above can take the place of two or even three of the prior art suture anchors previously used to form localised points of attachment.

The suture anchor described above is also completely removable if desired.

The invention is not limited to the embodiments described above. Various modifications and alterations will be apparent to a reader skilled in the art. For example, the number of prongs 22 can be varied about the circumference of the flange 14 and, if desired, the screw-receiving means need not be located centrally but can be arranged eccentrically of the flange. If desired, a bone screw can be irremovably attached to the suture anchor to provide a ready-to-use fixing device.

The suture anchor can be manufactured from any suitable implant grade material including various metals, plastics or ceramics.

Claims

1. A suture anchor for anchoring at least one suture in position, wherein the suture anchor has screw-receiving means for rotatably receiving a bone screw, suture-receiving means for receiving at least one suture and anchoring means for preventing relative rotation between the suture anchor and a bone into which the bone screw is screwed.

2. A suture anchor as claimed in claim 1, wherein the screw-receiving means comprise a through-aperture.

3. A suture anchor as claimed in claim 2, wherein the through-aperture is countersunk at the end thereof intended to receive the head of the bone screw.

4. A suture anchor as claimed in claim 2 or 3, wherein a central shaft is provided and the through-aperture extends through the shaft.

5. A suture anchor as claimed in any one of the preceding claims, wherein the anchoring means comprise a plurality of projections on or adjacent a surface of the suture anchor intended to come into contact with the bone.

6. A suture anchor as claimed in claim 5, wherein each projection has a sharp edge or point to facilitate entry into the bone.

7. A suture anchor as claimed in claim 5 or 6, wherein the projections are equispaced about a central axis of the anchor.

8. A suture anchor as claimed in any one of claims 5 to 7, wherein four projections are provided.

9. A suture anchor as claimed in any one of claims 5 to 8, wherein the suture-receiving means comprise a channel provided within the anchor, entry and exit ports to and from the suture-receiving channel being provided between the projections.

10. A suture anchor as claimed in any one of the preceding claims, wherein the anchor is formed from wrought stainless steel.

11. A suture anchor as claimed in any one of claims 1 to 9, wherein the anchor is made from a bioresorbable or bioabsorbable material.

12. A suture anchor for anchoring at least one suture in position substantially as hereinbefore described with reference to the accompanying drawings.

13. A fixing device for anchoring at least one suture comprising, in combination, a suture anchor according to any one of the preceding claims and a bone screw.

14. A fixing device as claimed in claim 13, wherein the bone screw is irremovably located in the screw-receiving means of the suture anchor.

15. A method of anchoring at least one suture utilising a suture anchor according to any one of claims 1 to 12, comprising the steps of: a) introducing a bone screw into the screw-receiving means of the anchor; b) introducing the threaded portion of the bone screw into the bone to which the at least one suture is to be anchored; c) introducing at least one suture into the suture-receiving means; and d) screwing the bone screw further into the bone so as to bring the anchoring means into direct contact with the bone thereby preventing rotation of the suture anchor with respect to the bone.

A A method of anchoring at least one suture utilising a fixing device according to claim 13 or 14, comprising the steps of: a) introducing the threaded portion of the bone screw into the bone to which the at least one suture is to be anchored; b) introducing at least one suture into the suture-receiving means; and c) screwing the bone screw further into the bone so as to bring the anchoring means into direct contact with the bone thereby preventing rotation of the suture anchor with respect to the bone.