Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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INSERTER FOR SUTURE ANCHORS
RELATED APPLICATION
This application is a division of Canadian Pa t ent
Application No. 2,145,249 filed March 22, 1995.
TECHNICAL FIELD
The field of art to which this invention relates is
surgical implements and more specifically inserters for
suture anchors.
BACKGROUND ART
As the treatment of injuries to joints and soft tissue has
progressed in the orthopaedic medical arts, there has been
a need for medical devices which can be used to attach
tendons, ligaments and other soft tissue to bone. When
surgically repairing an injured joint, it is preferable to
restore the joint by reattaching the damaged soft tissues
rather than replacing them with an artificial material.
Such restorations typically require the attachment of- soft
tissue such as ligaments and tendons to bone.
An increase in the- -incidence._ of ::.injuries....: to=_- joints
involving soft tissue has been observed. This increased
incidence may be due, at least in part, to an increase in
participation by the public in various physical activities
such as sports and other recreational activities. These
types of activities may increase the loads and stress
placed upon joints, sometimes resulting in joint injuries
with corresponding damage to associated soft tissue. In
1991, for example, there were approximately 560,000
surgical procedures performed in the United States in
which soft tissue was attached to a bone in various joints
including the shoulder, hip and knee.
One conventional orthopaedic procedure for reattaching
soft tissue to bone is performed by initially drilling
holes or tunnels at predetermined locations through a bone
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in the vicinity of a joint. Then, the surgeon
approximates soft tissue to the surface of the bone using
sutures threaded through these holes or tunnels. This
method, although effective, is a time consuming procedure
resulting in the generation of numerous bone tunnels.
A known complication of drilling tunnels across bone is
that nerves and other soft tissue structures may be
injured by the drill bit or orthopaedic pin as it exits
the far side of the bone. Also, it may be anatomically
very difficult to reach and/or secure a suture/wire that
has been passed through a tunnel. When securing the
suture or wire on the far side of the bone, nerves and
soft tissues can become entrapped and damaged.
In order to overcome some of the problems associated with
the use of the conventional bone__tunnel procedures, suture
anchors have been deveZoped'and-=are= frequently - used= to
attach soft tissue to bone. A suture anchor is an
orthopaedic, medical device which is typically implanted
into a-cavity drilled into a bone. Although less
frequently, these devices have also been referred to as
bone anchors. The cavity is typically referred to as a
bore hole and usually does not extend through the bone.
This type of bore hole is typically referred to as a
"blind hole". The bore hole is typically drilled through
the outer cortex layer of the bone and into the inner
cancellous layer. The suture anchor may be engaged in the
bore hole by a variety of inechanisms including friction
fit, barbs which are forced into the cancellous layer of
bone, etc. Suture anchors are known to have many
advantages including reduced bone trauma, simplified
application procedures, and decreased likelihood of suture
failure due 'to abrasion on bone. Suture anchors may be
used in the Bankart shoulder reconstruction for repairing
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the glenohumeral ligament and may also be used in surgical
procedures involving rotator cuff repair and hip
replacement.
Suture anchors typically have at least one suture
attached. This may be by means of a hole or opening for
receiving a suture or sutures. At least one end of the
suture extends out from the bore hole and is used to
attach soft tissue. The suture anchors presently
described in the art may be made of absorbable materials
which absorb over time, or they may be made from various
non-absorbable, biocompatible materials. Although most
suture anchors described in the art are made from non-
absorbable materials, the use of absorbable suture anchors
may result in fewer complications since the suture anchor
is absorbed and replaced by bone~over tirne=.- In addition,
the use of absorbable suture anchors may reduce the
likelihood of damage to local joints caused 'by anchor
migration.
Although suture anchors for attaching soft tissue to bone
are available for use by the orthopaedic surgeon, there is
a constant need in this art for novel suture anchors
having improved performance characteristics. There is also
a need for inserters for inserting such anchors.
SUMMARY OF THE INVENTION
Copending parent Application No. 2,145,249 filed March 22,
1995 discloses an apparatus for holding
one end of a prosthetic element such as a suture, which
apparatus comprises a head and an expandable body portion
which depends from said head. A wedging means is provided
for expanding the body portion by relative movement
between the wedging means and expandable body. The
expandable body may be comprised of at least two depending
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legs and may further include barb means on the outer
surface of the legs.
The wedging means may comprise a substantially spherical
object which further defines a hole therethrough for
receipt of a suture. The spherical object may ride within
a passage defined by the depending legs of the body.
The internal passage defined by the depending legs may
contain an internal constriction of smaller diameter than
the remainder of the passageway to hold the sphere in a
predetermined position once actuated or locked.
Additionally, this constriction of smaller diameter may
provide a tactile as well as an audible
indication of the passage of the wedging means from one
side of the constriction to the other.,..thus _from an
unlocked to a locked position. Preferably the passage
contains a constriction which holds the._wedging means in
a prefired or pre-engaged position;prior=to=spread-in_g:.-the
legs. The- suture- of -the -suture anchor may pass along side
the outside of the head or through an internal opening
within the head of the body of the suture anchor. The
internal surface of the legs of the suture anchor may
further be shaped to partially conform to the shape of the
spherical wedge when the sphere is in the seated position
above the constriction described. The head may further
include a stud extending therefrom for a gripping
apparatus to position the suture anchor within an opening.
The present invention provides an inserter for inserting
a suture anchor within an opening. The inserter
cooperates with a stud extending from the suture anchor
and includes an elongated section for receipt within a
trocar. A distal tip of the elongated section terminates
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in a tubular portion which receives the stud therein.
The suture is received by the suture anchor and run along
side the inserter in order to hold the suture anchor in
the inserter during the insertion process.
Alternatively, the tubular portion may be of a diameter
to provide a frictional fit with the stud. It may be
preferred to have the inserter provided with an outside
diameter at its head of the suture anchor to provide a
smooth transition between the two objects. Slots may be
defined in the outer surface of the inserter in order to
receive and protect the suture ends while the insertion
process is taking place. The inserter may include an
attachment mechanism for receiving and attaching at least
one end of the suture to hold the suture anchor on the
end of the inserter during the insertion process.
An alternative arrangement provides an inserter which is
cannular in nature that allows the suture material to
ride within the body of the inserter, thereby protecting
it from potential damage during the placement of the
suture anchor and/or during the actuation of the locking
means.
In one aspect, there is provided an inserter for
inserting a suture anchor of the type having a head, an
expandable body extending distally from the head and
comprising at least two legs, and a wedging means for
expanding the body by proximal relative movement of the
wedging means within the body, and having a stud
extending from the head, the inserter comprising: an
elongated section for receipt within a trocar; and a
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distal tip of said elongated section terminating in a
tubular portion for receipt of said stud therein.
In another aspect, there is provided an inserter, in
combination with and for inserting a suture anchor of the
type having a head, an expandable body extending distally
from the head and comprising at least two legs, and a
wedging means for expanding the body by proximal relative
movement of the wedging means within the body, and having
a stud extending from the head, the inserter comprising:
an elongated section for receipt within a trocar; and a
distal tip of said elongated section terminating in a
tubular portion for receipt of said stud therein.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the
accompanying drawings wherein:
FIG. 1 is a perspective view of an embodiment of the
suture anchor of the present invention in which the
actuating ball has not been assembled with the anchor
body;
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FIG. 2 is an enlarged perspective view of the suture
anchor of FIG. 1 after assembly and prior to insertion
into the bore hole of the bone;
FIG. 3 is a top plan view of the body of the suture anchor
of FIG. 1;
FIG. 4 is a front elevational view of the body of the
suture anchor of FIG. 1;
FIG. 5 is a bottom plan view of the body of the suture
anchor of FIG. 1;
FIG. 6 is a cross-sectional view taken along line 6-6 of
FIG. 3;
FIG. 7 is a plan view of the actuating ball of the suture
anchor of FIG. 1;
FIG. 8 is a cross-sectional view along lines 8-8 of FIG.
7;
FIG. 9 is a cross-sectional view showing implantation of
the suture anchor of FIG. 1 inserted into the bore hole of
the bone prior to actuation;
FIG. 10 is a cross-sectional view of the anchor and bone
after actuation of the suture anchor of FIG. 1;
FIG. 11 is a perspective view of an alternate embodiment
of the suture anchor;
FIG. 12 is a top plan view of the body of the suture
anchor of FIG. 11;
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FIG. 13 is a front elevational view of the body of the
suture anchor of FIG. 11;
FIG. 14 is a view along lines 14-14 of FIG. 12;
FIG. 15 is a cross-sectional view along lines 15-15 of
FIG. 12;
FIG. 16 is a elevational view of the actuating ball of the
anchor of FIG. 11;
FIG. 17 is a cross-sectional view along lines 17-17 of
FIG. 16;
FIG. 18 is a cross-sectional view of the bone with suture
anchor inserted prior to actuation;
FIG. 19 shows the suture anchor of FIG. 11 after
actuation;
FIG. 20 is a perspective view of an alternative embodiment
of the suture anchor of the present invention;
FIG. 21 is a top plan view of the body of the suture
anchor of FIG. 20;
FIG. 22 is a front elevational view of the body of the
suture anchor of FIG. 20;
FIG. 23 is a cross-sectional view along lines 23-23 of
FIG. 21;
FIG. 24 is a front elevational view of the act-uating ball
of the suture anchor of FIG. 20;
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FIG. 25 is a cross-sectional view along lines 25-25 of
FIG. 24;
FIG. 26 is a cross-sectional view of a bone having the
suture anchor inserted into a bore hole prior to
actuation;
FIG. 27 is a view of the suture anchor of FIG. 26 after
actuation;
FIG. 28 is a top plan view of an alternate embodiment of
the suture anchor of the present invention;
FIG. 29 is a front elevational view of the suture anchor
of FIG. 28;
FIG. 30 is a cross-sectional view taken along lines 30-30
of FIG. 28;
FIG. 31 is a perspective view of the suture anchor of
FIGS. 28-30;
FIG. 32 is a top plan view of the most preferred suture
anchor of the present invention;
FIG. 33 is a front elevational view of the suture anchor
of FIG. 32;
FIG. 34 is a cross-sectional view of the suture anchor of
FIG 32 taken along lines 34-34 of FIG. 32;
FIG. 35 is a perspective view of the suture anchor of
FIGS. 32-34;
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FIG. 36 is a side view of an implantation instrument for
the suture anchor of FIG. 35; and
FIG. 37 is a view of the tip of the instrument of FIG. 36.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1 a first embodiment of the suture
anchor of the present invention is shown. The anchor has
an anchor body 1 which is longitudinally extending and has
radially extending fins 2. A pair of diametrically
opposed slots are defined by the anchor body and extend
longitudinally from one end of the anchor body to a
position spaced from the second end of the anchor body.
These slots 3 create a pair of legs 4 in opposed positions
extending along the anchor body. A ball 6 is received
within a passage 7 defined by the legs 4 of- the anchor.
A suture opening 8 is defined through the ball 6 to
receive therein a suture 9. The ball is received within
passage 7 and held- in place- via-----a radially- inward
extending - rim -lE?--which-- causes- a constriction---of--the
opening of passage 7. The opening of passage 7 is
somewhat narrower than the diameter of the ball 6 such
that the ball is held within the suture anchor in the
initial condition. The passage 7 extends completely
through the body of the anchor as shown in FIG. 6. The
suture 9 is threaded through the suture opening 8 of the
ball and then both ends of the suture are in turn threaded
up through the longitudinal passage 7 and out the top of
the anchor through opening 7a defined in the top of the
anchor.
As can be seen in FIG. 6 the longitudinal passage 7 tapers
towards its top end: Thus, as seen in FIG. 9 the suture
anchor may be placed in an appropriate bore hole prepared
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in a bone site. The ball is initially held in place by
the rim 10 but upon implantation within the opening of the
bone, the ball is pulled upward toward the head 5 of the
anchor and cooperates with the tapered inner passage to
force legs 4 outward. At this point the legs and fins 2
dig into the softer cancellous layer of the bone thus
fixing the anchor in place.
An alternate embodiment is shown in FIG. 11. This
embodiment is substantially similar to the embodiment
previously described, however, it is provided with three
fins instead of the two spaced radially extending fins
previously described as well as having four slots 3
defined along the longitudinal portion of the anchor such
that four separate legs 4 are defined thereby. Again, the
central passage.:is tapered slightly, however, :the=fins
extend to a position further down longitudinally along the
legs 4 such that additional gripping force is provided.
In this manner : as: .. seen in: _ FIG.---.18 the : device may .be
inserted into a shallower hole whereby the movement of the
ball upward causes the lower fins to dig into the soft
cancellous layer of the bone.
A further alternate embodiment is shown in FIG. 20. This
embodiment has an anchor body 1 with fins 2 defined
thereon similar to the first embodiment. A pair of slots
3 are defined along the anchor body and in turn define a
pair of legs 4 extending longitudinally along the anchor
body. A cap 11 which may be solid in construction is
formed at one end. A ball 6 is received within a passage
7 and defines therethrough a suture opening S. A suture
9 is received within the suture opening 8 with the ends of
the--'suture extending through the slots and along the
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outside of the anchor 11. This distinguishes this anchor
from the anchors previously described.
The fins 2 have a top surface 12 and a tapering bottom
surface 13. The top surface 12 and the bottom surface 13
meet to form an edge 14 which will bite into the soft
cancellous bone of the anchor site.
As is seen in Figs. 26 and 27, an appropriate bore hole is
bored through the hard outer cortex of the bone into the
soft cancellous layer beneath. The suture anchor is
inserted into the opening with the ends of the suture
extending through the passage in the ball along the slots
and adjacent the cap of the suture. Once inserted within
the bore opening, force is applied to the ends of the
suture in order to _ draw __the _ba 11 upward into. the suture
anchor. As is seen best- in Fig. 23, a small compartment
15 is provided for seating the ball prior.to actuation of
the device. Upon actuation of- the device, the-_ball_is
drawn upward aiong--cam - surface 16 which - initiates the
spreading of the legs into narrow passage 17 where the
ball rests after implantation of the device.
The preferred device of the invention is shown in Figs.
28-35. This embodiment includes an anchor body 20 which
has a pair of depending legs 21 extending downward from
the body. The legs 21 define a pair of slots 22 which
permit expansion of the legs as will be described below.
The legs in part define an inner passage 23 for receipt of
an actuation ball as will be described below.
The distal opening of the inner passage 23 has a radially-
extending rim 24 which adapts to hold the ball in the
holding portion 25 as shown by phantom lines in Fig. 30.
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A camming constriction 26 extends radially inward into the
inner passage 23. This camming constriction and the
remainder of the passage define a seating portion 27.
As. may be seen by Fig. 30, the slots 22 extend beyond the
seating portion 27. This permits passage of the suture
out of the inner passage through the slots and also
increases the range of motion of the legs without cracking
of the legs.
The embodiment shown in Figs. 32-35 is similar in its
definition of its inner passage and camming constriction
and slot, however it contains additional fins 28 which
help to center the anchor within the bore hole of the
bone. The bottom fin 34 actually provides a thickened
portion in order to maintain -the wall integrity in the
area where the ball is initially seated. The ball 30 is
received within this seating portion adjacent the bottom
f in 34. The ba l l. def ines - a' suture -passage - 31 which
receives a suture 32. The openings of -t2ie suture passage
31 are rounded slightly in order to reduce abrasion of the
suture.
A stud 33 extends from the anchor body 20 in a
longitudinal direction. This assists in the implantation
of the device as will be described in connection with the
apparatus of Figs. 36 and 37.
The anchors of the present invention may be made from
either conventional bioabsorbable materials or
conventional non-absorbable materials, combinations
thereof and equivalents thereof. Examples of absorbable
materials include homopolymers and copolymers of lactide,
glycolide, trimethylene carbonate, caprolactone, and p-
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dioxanone and blends or other combinations thereof and
equivalent thereof. Of particular utility are the
polylactides, especially poly[L(-)lactide], and the
lactide-rich lactide/glycolide copolymers, especially 95/5
poly[L(-)lactide-co-glycolide].
Examples of non-absorbable materials from which the suture
anchors of the present invention may be made include
metallic biocompatible materials including stainless
steel, Nitinol, titanium, Vitalium and equivalents
thereof, polymeric materials such as non-absorbable
polyesters, polyamides, polyolefins, polyurethanes, and
polyacetals and equivalents thereof, when metallic
substances are used, then softer metals are preferred.
The suture anchor--devices of the present invention, when
made from an absorbable material, are preferably
manufactured by molding using conventional injection
molding equipment- ~:and. . conventional--Anjectibn . molding
processes:- A typical molding process includes the steps
of (1) injecting a suitable polymer melt into an
appropriately designed mold or cavity at process
conditions conventionally employed for such polymer
systems, (2) releasing from the mold, after the melt cools
in the mold, polymer shaped in the proper configuration to
meet the design criteria of the device. Additionally the
anchor molded from the absorbable polymeric material, may
be advantageously subjected to an annealing process to
increase its mechanical or biological performance.
Thermal annealing can also be used to increase the
dimensional stability of molded parts by increasing the
crystallinity levels in the parts. One or more surgical
sutures, or one or more sutures with surgical needles
attached, may be used in combination with the suture
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anchor and may be assembled prior to sterilization. The
device can then be sterilized using conventional methods
to render the anchor suitable for surgical applications.
The bonding of the anchors of the present invention to
bone may be advantageously increased by promoting bone
growth. This can be accomplished by having a microporous
surface into which the bone can rapidly grow to aid
fixation. This may be particularly advantageous in the
case of a metallic anchor, especially a titanium or
titanium alloy anchor, but may also provide benefit in the
case of polymeric anchors of the present invention,
especially those made of absorbable materials. Other
methods include the coating of the anchor's surface with
a substance to promote adhesion to the bone. Such
coatings include the hydroxyapatite-containing-glass
coatings described' by Ishikawa, et al., in the article
"Effect of Hydroxyapatite Containing Glass Coating on the
Bonding between1 Bone and:-Titanium Implants'!_ appearing.in.
Clinical Materials,'Volume'14;'1993; pages 277-2-85:
It is further noted that the anchors of the present
invention can be made to contain growth factors,
especially bone growth factors, that can advantageously
increase the effectiveness of the anchors, especially in
the area of fixation. This may be accomplished in a
number of ways, including via coatings or, in the case of
absorbable materials by incorporating the growth factors
within the device and allowing them to diffuse out.
The implantation instrument for the preferred device is
shown in Fig. 36. The device has a handle 35 which has
extending therefrom a shaft 36. The shaft 36 terminates
in a narrower holding portion 37 which is adapted -to
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receive the stud 33 of the suture anchor within a
cylindrical seat 38 defined in the tip of the holding
portion. A pair of diametrically opposed relief slots 39
are provided for the passage of the suture from the anchor
along the shaft. That is, the suture is received within
the suture passage defined in the ball and extends outward
from the anchor and along the shaft of the apparatus. The
suture, as it extends along the shaft of the apparatus, is
received within the relief slots 39 and extends upward to
the cleats 40 which extend from either side of the handle
35. Thus, in use, the stud of the suture anchor is
received within the cylindrical seat 38. An appropriate
suture extends through the suture passage of the ball and
is laid along the relief slots 39 and attached to the
cleats 40 thus holding the anchor in place. In an open
procedure or an arthroscopic procedure,. the-anchor is
inserted into a previously bored hole in the bone of the
recipient. Once in place in the bored hole the suture is
detached from the =cleats.- and .upward force is -appliect-.to
the suture while keeping the anchor in place drawing the
ball into the seating portion of the anchor. The action
of drawing the ball into the seating portion forces the
legs outward as the ball passes the camming constriction
and causes the legs and fins to dig into the softer
cancellous bone. Thus the suture anchor is implanted
within the bore and prepared for attachment of soft tissue
to the bone.
The invention has been described with reference to its
preferred embodiments, however, it is understood that
changes may be made to the invention without departing
from the spirit of the disclosure provided herein.
