Note: Descriptions are shown in the official language in which they were submitted.
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SURGICAL ANCHOR FOR LIGAMENTS
The present invention concerns an anchor for
attaching ligaments to bones, in ligament reconstruction
surgery; it more particularly concerns such an anchor
intended for being set in place by arthroscopy.
5 - 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 longitudinal orientation (parallel to the suture)
thr~ugh the cannula and, once it emerges from the cannula,
10 the anchor rotates to an angle relative to the suture, and
so to seats on the soft tissues.
Such anchors are for examples disclosed in
EP-A-0236427 and EP-A-0464480.
It is on the other hand known in orthopaedic surgery,
15 in the ligament reconstruction, to pierce through the joint
a t:unnel or blind hole for receiving the ends of the
ligament. At its proximal end, this tunnel is continued by
a n~rrower or pull tunnel for a passing pin instrument.
When the ligament is inserted, it is attached to a
20 pul:Ling lead which i5 driven within the successive tunnels
and pushed up to outside the skin with a passing pin
inslrument, which is driven within the tunnels and through
the skin; the pulling lead is thereafter used to pull the
ligament substantially up to the end of the tunnel.
Once the ligament is inserted, it must be firm:Ly
anchored in position.
The conventionnal method includes knotting the
pul]ing leads for the ligament at the mouth of the pull
tunnel, on a retaining member such as a button, a clip, a
30 screw, etc. This attachment needs thus to surgically acc:ess
the bone area where the pull tunnel emerges.
An alternative method is performed entirely under
arthroscopic monitoring. In this method, and after the
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tunr;els in the bones have been made, the anchoring member
is 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 opposed
5 direction, the anchor thereafter blocks at the end of the
push tunnel.
This method is less traumatic since it is not
necessary for anchoring, to make an opening at the proximal
side. It however requires to feed the anchor through the
lo pull tunnel which must thus be larger than for the passing
pin instrument of the pulling lead, and it is a concern
that the anchor be the narrowest possible, for m;nimi sing
the diameter of the pull tunnel.
The anchors to be pushed referred to hereabove are
15 not appropriate for attaching ligaments. Indeed, this would
req~Lire enlargment of the bone tunnels for allowing
simultaneous passage of the ligament and of the insertion
device, which is opposed to the requirements aiming to
matc:h as closely as possible the diameter of the ligament
20 and the size of the tunnel for enhancing biological
attacl-Lment .
Moreover, the insertion cannula would tend to wound
the ligamentary structure during handling for putting in
plac:e.
25For this kind of application, pull anchors have t:hus
been developped, which can be set in place without cannula
inst:rument .
Such an anchor is known for example by
EP-A-O 619 982, which discloses a substantially cylindrical
30 anchor, provided with peripheral barbs. When this anchor
emerges oustide, at the proximal end of the pull tunnel,
the barbs provide the anchoring by seating on the surface
of t:he cortical bone.
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This anchor is however difficult 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.
When not, the short barbs would extend loosely inside, and
5 could not seat on the cortical bone at the mouth of the
tunnel.
So, 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 not emerged
10 from the tunnel. To ascertain this fact, the surgeon indeed
pulls in the opposite direction (side of the ligament), and
the barbs would then tend to wedge the anchor within the
bone, already inside the tunnel, so that the right setting
of the anchor can actually only be ascertained by accurate
15 measuring and marking of the graft provided with the
anchor, relative to the length of the bone tunnel, or still
by radioscopic monitoring, all these handling being
technically critical, and time consuming.
Another drawback of this anchor is yet that the bone
20 surface on which the barbs seat is generally not flat, nor
perpendicular to the longitll~;n~1 axis of the anchor, in
whi~h case the support results from only two barbs.
One also know (patent US-A-5306301) an anchor in the
for]~ of an elongated plate, pierced by four holes
25 substantially aligned in the longitudinal direction of the
plate (EndoButton~ from Acufex Microsurgical Inc.). The two
medial holes are used for attaching the ligament, and the
two external holes are used for attaching pulling leads.
This anchor is inserted longit~ n~1 ly in the pull
30 tunnel, through the pulling leads, until it emerges at its
proximal end. Once emerged from the tunnel, a pulling on
the posterior pulling lead make it rotate about an axis
perpendicular to its longitudinal axis, and it is driven
bac]~ by a pull on the ligament side, so as to make it seat
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on the rim of the tunnel, with its longitudinal i~xis
substantially perpendicular to the axis of the tunnel.
According to the invention, one proposes to provide
an anchor of this kind, easier to make and to handle, and
5 before all of lower size, so that it can be driven through
a ni~rrower pull tunnel, with less weakening of the bone" or
allows to use it for smaller, or less strong bones.
The solution according to the invention comprises
providing a surgical anchor for attaching a ligament or the
o like, at the proximal mouth 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 on one hand pulling means, and on the
other hand attachment means for a ligament or the l:Lke,
15 said anchor being provided for pivoting perpendicularly to
its longitudinal axis at the mouth of the tunnel, to lay in
blocking position substantially perpendicularly to the c~xis
of lhe tunnel,
characterized in that
20 - the passage means for the pull means is made of a
single milling perpendicular to the longitudinal ax:is
of the elongated body, and
- the passage means for the attachment means for the
ligament or the like is made of a single mil]ing
perpendicular to the longitll~;n~l axis of the
elongated body.
According to another feature of the invention, the
millillg for the ligament attachment means is a milling with
a narrow and elongated section, with a long side parallel
30 to the longitudinal axis of the elongated body, provided
for receiving a flat, ribbon like ligament attachment
means~
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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
5 attachment means for the ligament or the like, driven in
the milling of the elongated body, is attached thereto
while being retained by a reinforced tickness at its end,
which can not pass within the milling.
According to another feature of the invention, the
10 attachment means for the ligament or the like is attached
to the elongated body while being inserted within said
milling like a lead in a needle.
According to another feature of the invention, the
two filaments of the attachment means are whipped near the
15 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
20 elongated body has a substantially cylindrical section.
Other aspects, characteristics and advantages of the
invention will appear from the detailed description which
folLow, and the annexed drawings, in which:
Figure 1 is a side view, partially broken away, oi- an
25 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
30 according to the invention, with another 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.
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Referring to the drawing, the anchor 1 comprises a
generally cylindrical, elongated body 2 with a through
milling 3 the longit~ n~ l axis A-AI of which is
substantially perpendicular to the longitudinal axis :B-B'
5 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 direction B-B' of the cylindrical
body 2.
The milling 3 is provided for insertion of an
attachment means 4 for a ligament or the like, as well ,~s a
pulling lead 5.
The pulling lead 5 is used only during the operat.ion,
for allowing the surgeon to pull the anchor within the
15 insertion tunnel 6 for the ligament or the like, then
wit:hin the narrower pull tunnel continuing the later, w].lile
drawing the ligament 8 substantially up to the end of the
insertion tunnel 6. The insertion and pull tunnels are
pie:rced through the bone 9 to which the ligament must: be
20 attached.
Once the anchor is set in place, the lead 5 is
wit].ldrawn, most conveniently by pulling one filament
the:reof.
The ligament attachment means is used not only for
25 pul:Ling 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 with an elongated section according to
30 the lnvention presents a passage of a relatively large
section for a narrow slit; in conjunction with flat, ribbon
like attachment means 4, it allows to give it a section
sufi-icient for supporting the stress to which it will be
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subjected, and this for a short diameter of the cylindrical
body 2.
At Figure 2, the attachment ribbon 4 and the pulling
lead 5 are represented as threaded through the milling 3
5 like a lead in the eye of a needle, which constitutes the
simplest and the most reliable means for attaching the
attachment ribbon 4 and the pulling lead 5 to the
cylindrical body 2. The two filaments of the ribbon 4 are
on the other hand whipped together, as shown by the dotted
o line 11.
In the alternative of figure 3, the pulling ribbon is
represented with an extra tickness 10 at its free end,
opposed to the ligament, so as to prevent the thre/ded
ribbon to get out the milling. This is however a less
15 prefered embodiment, since less reliable.
A single milling 3, which is used both for the
pulling lead and for the attachment ribbon, and which
con,titutes a prefered embodiment of the invention, has
bee~ shown in the drawings. The invention is obviously not
20 limited to this embodiment, and two individual millings may
also be provided for, or yet one milling for the attachment
ribbon and one hole for the pulling lead; this leads
however to no particilar advantages.
For convenience, the single milling will preferably
25 be made symetrically in the middle of the body, so that the
anchor be perfectly symetrical, and does not present a
forward and a rearward ends.
At figure 4, the anchor is shown during inserlion
within the pull tunnel 7 pierced in a bone 9, following the
30 insertion tunnel 6 for the ligament or the like.
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 lead 5 is inserted within the
tunnels 6, 7 with the aid of a passing pin instrument that
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the surgeon makes to emerge outside, proximally, by
piercing the skin; once the lead is outside, the surgeon
can take it directly in hand, and pull the anchor and the
ligament within the tunnels.
As seen in figure 4, the pulling lead lays down
longitll~in~lly relative to the cylindrical body, while both
filaments of the ribbon distord (twist) to lay down also
longitudinally relative to the cylindrical body 2.
When the anchor emerges from the tunnel 7, it tends
o to erect (to rotate perpendicularly to its longitudinal
axis), inter alia due to the asymetrical attachment of the
ribbon 4. Thus, it does not remain aligned with the axis of
the tunnel and, when the surgeon pull in the opposite
direction, on the side of the ligament, the rounded end of
15 the anchor contacts the bone wall at the mouth of the
tunnel. By a continued pulling on the ligament side -
optionaly in conjunction with short pulls on the pull lead
side, the surgeon drive the anchor in seating positlon,
transversaly to the axis of the pull tunnel.
At figure 2, a whipping of the two filaments of the
attachment ribbon 4, near the cylindrical body 2, is shown
a dotted line 11. The purpose of this whipping is to force
the ribbon to lay as showrt in figure 4, with its edges 4',
4" substantially perpendicular to the longitll~;n~l axis of
25 the body 2, while thus preventing the ribbon to lay down
longitll~i n~ 1 ly like the pull lead 5, which would reduce the
tendancy of the body to erect.
This whipping can however be replaced by a mere
knotting of the two filaments, which provides the same
30 effect, with however the drawback to be more bulky than the
whipping, what 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 the less traumatism, by
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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.
So, according to the invention, a diameter of the
5 body 2 of the order of 2,5 mm or even 2 mm is easily
reached, to be compared with a transverse ~;men.sion of
about 4 mm for the Endobutton~ plate, or a diameter of
about 5 mm for the anchor according to EP-A-O 619 982.
By "milling" it is meant in the present description a
lo through perforation of the body of the anchor, which ca:n be
made by a mill, but also by any other means, for example a
Laser.
