AU1943195A

AU1943195A - Surgical anchoring piece for ligaments

Info

Publication number: AU1943195A
Application number: AU19431/95A
Authority: AU
Inventors: Michel Collette
Original assignee: Soc D Gestion Jarim N V
Current assignee: Gestion Jarim Nv Ste
Priority date: 1995-03-21
Filing date: 1995-03-21
Publication date: 1996-10-08
Also published as: WO1996029029A1; CA2215943A1; EP0814730A1

Description

SURGICAL ANCHOR FOR LIGAMENTS The present invention concerns an anchor for attaching ligaments to bones, in ligament reconstruction surgery; more particularly, it concerns such an anchor intended for being set in place by arthroscopy. Anchors for sutures, intended for being pushed through a cannula device, are known in arthroscopic surgery. The anchor with the suture attached thereto is pushed in longitudi nal orientation (parallel to the suture) through the cannula and, once it emerges from the cannula, the anchor rotates at an angle relative to the suture, so as to rest on the soft tissues. Such anchors are described, for example, in documents EP-A-0236427 and EP-A 0464480. On the other hand, it is known in orthopaedic surgery, in ligament reconstruction, that one can pierce a tunnel or blind hole through the joint for receiving the ends of the ligament. At its proximal end, this tunnel is continued by a narrower or pull tunnel for a passing pin instrument. When the ligament is inserted, it is attached to a pulling thread which is driven within the successive tunnels and pushed up to outside the skin with a passing pin instrument, which is driven within the tunnels and through the skin; the pulling thread is thereafter used to pull the ligament substantially up to the end of the tunnel. Once the ligament is inserted in position, it must be firmly anchored in place. The conventional method includes knotting the pulling threads for the ligament at the exit of the pull tunnel, on a retaining member such as a button, a clip, a screw, etc. This attachment needs thus to surgically access the bone area where the pull tunnel emerges. An alternative method is performed entirely under arthroscopic monitoring. In this method, and after the tunnels in the bones have been made, the anchoring member is 1 attached to the ligament, and the assembly is thereafter pulled in the bone tunnels until the anchor completely emerges from the pull tunnel; by pulling in the opposite direction, the anchor thereafter becomes blocked at the end of the push tunnel. This method is less traumatic since it is not necessary to make an opening at the proximal side for anchoring. It, however, requires feeding the anchor through the pull tunnel which must thus be larger than that for the passing pin instrument of the pulling thread, and it is important that the anchor be as narrow as possible, to minimize the diameter of the pull tunnel. The anchors to be pushed referred to above are not appropriate for attaching liga ments. Indeed, this would require enlargement of the bone tunnels for allowing simultaneous passage of the ligament and of the insertion device, which is contrary to the requirement to adjust the diameter of the ligament to the size of the tunnel as closely as possible to enhance biological attachment. Moreover, the insertion cannula would tend to injure the ligamentary structure during the positioning manipulation. For this kind of application, pull anchors have been developed, which can be set in place without a cannula instrument. Such an anchor is known for example from EP-A-0 619 982, which discloses a substantially cylindrical anchor, provided with peripheral barbs. When this anchor emerges outside, at the proximal end of the pull tunnel, the barbs provide the anchoring by resting on the surface of the cortical bone. This anchor is, however, delicate to use; indeed, the barbs must be short to avoid wedging thereof in the bone tunnel, so that the pull tunnel must be closely adjusted. Otherwise the short barbs would "float" inside, and could not rest on the cortical bone at the exit of the tunnel. Thus, the anchor moves with high friction within the pull tunnel, and it is difficult for the surgeon to determine exactly whether the anchor has or has not emerged from the tunnel. 2 To ascertain this fact, the surgeon indeed pulls in the opposite direction (side of the liga ment), and the barbs already inside the tunnel would then tend to wedge the anchor within the bone, so that the right setting of the anchor can actually only be ascertained by accurate measuring and marking of the graft provided with the anchor, relative to the length of the bone tunnel, or by radioscopic monitoring, all these manipulations being technically delicate and time-consuming. Another drawback of this anchor is that the bone surface on which the barbs rest is generally neither flat nor perpendicular to the longitudinal axis of the anchor, in which case the support results from only two barbs. An anchor in the form of an elongated plate, pierced by four holes substantially aligned in the longitudinal direction of the plate (EndoButton* from Acufex Microsurgical Inc.) is also known (patent US-A-5306301). The two median holes are used for attaching the ligament, and the two external holes are used for attaching pulling threads. This anchor is inserted longitudinally in the pull tunnel, through the pulling threads, until it emerges at its proximal end. Once emerged from the tunnel, pulling on the posterior pulling thread makes it rotate around an axis perpendicular to its longitudinal axis, and it is driven back by a pull on the ligament side, so as to make it rest on the rim of the tunnel, with its longitudinal axis substantially perpendicular to the axis of the tunnel. According to the invention, it is proposed to provide an anchor of this kind, easier to make and to handle, and above all of smaller size, so that it can be driven through a narrower pull tunnel, with less weakening of the bone, and it also allows application to smaller or weaker bones. The solution according to the invention comprises providing a surgical anchor for attaching a ligament or the like, at the proximal exit of a tunnel pierced in a bone, made of an elongated body provided with passage means perpendicular to the longitudinal axis of the elongated body, for attaching pulling means, as well as attachment means for a ligament or the like, said anchor being provided for pivoting perpendicularly to its longitudinal axis at the end of the tunnel, to lay in a blocked position, substantially perpendicular to the axis of the tunnel, 3 characterized by the fact that - the passage means for the pull means is made of a single milling perpendicular to the longitudinal axis of the elongated body, and - the passage means for the attachment means for the ligament or the like is made of a single milling perpendicular to the longitudinal axis of the elongated body. According to another feature of the invention, the milling for the ligament attachment means is a milling with a narrow and elongated cross-section, with a long side parallel to the longitudinal axis of the elongated body, provided for receiving a flat, ribbon-like ligament attachment means. According to another feature of the invention, the milling for the pulling means and the milling for attaching the ligament are a single common milling. According to another feature of the invention, the attachment means for the ligament or the like, driven in the milling of the elongated body, is attached thereto while being retained by an excess thickness at its end, which cannot pass within the milling. According to another feature of the invention, the attachment means for the ligament or the like is attached to the elongated body while being inserted within said milling like a thread in a needle. According to another feature of the invention, the two filaments of the attachment means are ligated near the surface of the elongated body. According to another feature of the invention, the two filaments of the attachment means are knotted near the surface of the elongated body. According to another feature of the invention, the elongated body has a substantially cylindrical section. 4 Other aspects, characteristics and advantages of the invention will appear from the detailed description which follows, and the attached drawings, in which: Figure 1 is a side view, partially broken away, of an anchor according to the invention, Figure 2 is a perspective view of the anchor of the invention, provided with pulling means and means for attaching a ligament or the like, Figure 3 is a cross-sectional view of the anchor according to the invention, with another mode of attachment of the attachment means for the ligament or the like, Figure 4 is a view of the anchor being driven through the tunnel pierced in a bone. Referring to the drawing, the anchor 1 comprises a generally cylindrical, oblong body 2 with a through milling 3, the longitudinal axis A-A' of which is substantially perpendicular to the longitudinal axis B-B' of the cylindrical body 2. As it can be seen from the drawing, the milling has the form of a slit 3, and has an elongated cross section along the longitudinal axis B-B' of the cylindrical body 2. Milling 3 is provided for insertion of an attachment means 4 for a ligament or the like, as well as a pulling thread 5. The pulling thread 5 is used only during the operation, to allow the surgeon to pull the anchor through the insertion tunnel 6 for the ligament or the like, then through the narrower pull tunnel 7 that is a continuation of the latter, while drawing the ligament 8 substantially up to the end of insertion tunnel 6. The insertion and pull tunnels are pierced through the bone 9 to which the ligament must be attached. Once the anchor is set in place, the thread 5 is withdrawn, most conveniently by pulling one filament thereof. 5 The ligament attachment means is used not only for pulling the ligament substantially up to the end of the insertion tunnel 6, during the operation, but is also used for anchoring the ligament to the bone, and it must thus be sized accordingly. The milling 3 with an elongated cross-section according to the invention presents a passage of a relatively large cross-section for a narrow slit; in conjunction with flat, ribbon like attachment means 4, it allows to give it a sufficient cross-section for supporting the stress to which it will be subjected, and this for a short diameter of the cylindrical body 2. In Figure 2, attachment ribbon 4 and pulling thread 5 are represented as threaded through milling 3 like a thread in the eye of a needle, which constitutes the simplest and the most reliable means for attaching the attachment ribbon 4 and the pulling thread 5 to the cylindrical body 2. The two filaments of the ribbon 4 are on the other hand tied together, as shown by the dotted line 11. In the alternative of Figure 3, the pulling ribbon is represented with an excess thickness 10 at its free end, opposite to the ligament, so as to prevent the threaded ribbon from leaving the milling. This is, however, a less preferred embodiment, since it is less reli able. A single milling 3, which is used both for the pulling thread and for the attachment ribbon, and which constitutes a preferred embodiment of the invention, has been shown in the drawings. The invention is obviously not limited to this embodiment, and two individual millings may also be provided, or one milling for the attachment ribbon and one hole for the pulling thread; this leads, however, to no particular advantages. For convenience, the single milling will preferably be made symmetrically in the middle of the body, so that the anchor be perfectly symmetrical, and does not present a front and back end. In Figure 4, the anchor is shown during insertion within the pull tunnel 7 pierced in a bone 9, following the insertion tunnel 6 for the ligament or the like. 6 In a known manner, the tunnels are pierced in the bone after an opening has been made in the soft tissues at the distal end, and the pull thread 5 is inserted within the tunnels 6, 7 with the aid of a passing pin instrument that the surgeon makes to emerge outside, proximally, by piercing the skin; once the thread is outside, the surgeon can hold it directly in his hand, and pull the anchor and the ligament within the tunnels. As seen in Figure 4, the pulling thread is arranged longitudinally relative to the cylindrical body, while both filaments of the ribbon are deformed (twisted) to be arranged also longitudinally relative to the cylindrical body 2. When the anchor emerges from the tunnel 7, it tends to erect (to rotate perpendic ularly to its longitudinal axis), among others, due to the asymmetrical attachment of ribbon 4. Thus, it does not remain aligned with the axis of the pull tunnel, and, when the surgeon pulls in the opposite direction, on the side of the ligament, the rounded end of the anchor contacts the bone wall at the exit of the tunnel. By continued pulling on the ligament side optionally in conjunction with short pulls on the pull thread side, the surgeon drives the anchor in the seating position, transversely to the axis of the pull tunnel. In Figure 2, the ligation of the two filaments of attachment ribbon 4, near the cylindrical body 2, is shown by dotted line 11. The purpose of this ligation is to force the ribbon to lay as shown in Figure 4, with its edges 4', 4" substantially perpendicular to the longitudinal axis of the body 2, thus preventing the ribbon to lie down longitudinally like the pull thread 5, which would reduce the tendency of the body to erect. This ligation can, however, be replaced by a mere knotting of the two filaments, which provides the same effect, however, with the drawback of being more bulky than the ligation, which then requires a larger pull tunnel. According to the invention, an improved surgical anchor has been provided, which allows anchoring a ligament by arthroscopy, and thus with less trauma, by reducing substantially the diameter of the pull tunnel to be pierced in the bone, and providing a safe blocking of the anchor, with no recourse to radioscopy or the like. 7

Claims

1. Surgical anchor (1) for attaching a ligament or the like, at the proximal exit of a tunnel pierced in a bone, made of - an elongated essentially cylindrical body (2) provided with a first passage perpendicu lar to the longitudinal axis (B-B') of the elongated body, for attaching a pulling means (5), and with a second passage perpendicular to the longitudinal axis of the elongated body, for attaching an attachment means (4) for a ligament or the like, - pulling means and attachment means for a ligament, inserted respectively in said respective passage, characterized by the fact that - the milling for the ligament attachment means is provided in the median portion of the elongated body, and - the ligament attachment means is attached asymmetrically to the cylindrical body, - the anchor being intended for attaching a ligament by pivoting across the tunnel, at the exit thereof. 8

2. Anchor according to Claim 1, characterized by the fact that the milling for the ligament attachment means is a milling (3) with a narrow and elongated cross-section, with a long side parallel to the longitudinal axis (B-B') of the elongated body (2), provided for receiving a flat, ribbon-like ligament attachment means (4).

3. Anchor according to Claim 1 or 2, characterized by the fact that the milling for the pulling means and the milling for attaching the ligament are a single common milling (3).

4. Anchor according to any of Claims 1 to 3, characterized by the fact that the attachment means (4) for the ligament or the like, threaded in the milling (3) of the elongated body (2), is attached thereto while being retained by an excess thickness (10) at its end, which cannot pass within the milling.

5. Anchor according to any of Claims 1 to 3, characterized by the fact that the attachment means (4) for the ligament or the like is attached to the elongated body (2) while being threaded within said milling (3) like a thread in a needle.

6. Anchor according to Claim 5, characterized by the fact that the two filaments of the attachment means (4) are ligated (11) near the surface of the elongated body.

7. Anchor according to Claim 5, characterized by the fact that the two filaments of the attachment means (4) are knotted near the surface of the elongated body (2).

8. Anchor according to any of the preceding claims, characterized by the fact that the elongated body (2) has an essentially circular cross-section. 9