CA 02417170 2003-02-11
-1-
APPARATUS AND METHOD FOR
ANCHORING A CORD-LIKE ELEMENT TO A WORKPIECE
Field Of The Invention
The field of art to which this invention
relates is apparatus and methods for anchoring a cord-
like element to a workpiece, and more specifically suture
anchors for anchoring suture material to bone.
Background Of The Invention.
As the treatment of injuries to joints and soft
tissue has progressed in the orthopedic 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, for
example, it is often 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, ait 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 orthopedic procedure for
reattaching soft tissue to bone is performed by initially
drilling holes or tunnels at predetermined locations
through a bone in the vicinity of a joint. Then, the
surgeon approximates soft tissue to the surface of the
CA 02417170 2003-02-11
-2-
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 orthopedic
pin as it exits the far side of the bone . Also, it is
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 developed and are
frequently used to attach soft tissue to bone. A~suture
anchor is an orthopedic, medical device which is
typically implanted into a cavity drilled into a bone.
Although less frequentlyF 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
mechanisms 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 the glenohumeral ligament
and may also be used in surgical procedures such as
rotator cuff repair and hip replacement. Also, such
anchors may be used in repair of tendon tears by direct
attachment of bone to bone.
Suture anchors typically have at least one
CA 02417170 2003-02-11
-3-
suture attached. This may be by means of a hole or
opening for receiving the suture(s). At least one end
and typically both ends of the suture strand extend out
from the bore hole and are 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 time. 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 orthopedic
surgeon, there is a constant need in this art for novel
suture anchors having improved performance
characteristics.
It has now also been recognized that suture
anchors may have application in fields other than
orthopedics. By way of example but not limitation,
suture anchors may be employed in a field such as plastic
surgery to stabilize tissue to bone. In these non-
orthopedic applications, the deployment location of the
suture anchor may necessitate that the suture anchor be
formed as small as possible. For example, the suture
anchor may need to be deployed in a relatively small
facial bone. At the same time, however, the loads placed
on such a suture anchor may be much less than the loads
placed on an orthopedic suture anchor, thus giving rise
to a range of different design considerations.
Thus there is also a need for improved suture
anchors which may be used in non-orthopedic applications,
including plastic surgery and the like.
CA 02417170 2003-02-11
-4-
Summary Of The Invention
These ar_d other objects of the. present
invention are achieved through the provision and use of
a novel system and method for anchoring a suture or other
cord-like element to a bone or other workpiece.
In one form of the present invention, the
system comprises a drill for forming an undercut hole in
a bone or other workpiece, an anchor for securing a
suture or other cord-like element in the undercut hole in
the bone or other workpiece, and an inserter for
deploying the anchor in the undercut hole in the bone or
other workpiece.
In one form of the present invention, the drill
comprises a shaft having a proximal end., a distal end and
a first longitudinal axis; a re-centering element
attached to the distal end of the shaft, the re-centering
element including a distally-tapering portion centered on
a second longitudinal axis parallel to, but laterally
spaced from, a projection of the first longitudinal axis;
a connecting member centered an the second longitudinal
axis, the connecting member having a proximal end and a
distal end, the connecting member extending distally from
the re-centering member and being attached at the
proximal end of the connecting member to the distally-
tapering portion such that the connecting member and the
distally-tapering portion together define a beveled
corner centered on the second axis; and a substantially
cylindrical drill head centered on an axial projection of
the first longitudinal axis, the drill head having a
proximal end, a distal cutting tip, an outer surface
defining cutting flute means extending between the distal
cutting tip and the drill head proximal end, and a
transverse cross-section larger than the transverse
cross-section of the connecting member; the proximal end
of the drill head being eccentrically attached to the
distal end of the connecting member.
In one form of the present invention, the
CA 02417170 2003-02-11
-5-
anchor comprises a body of resilient material including
a longitudinal axis, a distal end, a distal portion
adjacent to the distal end, a proximal end, a proximal
portion adjacent to the proximal end, and an intermediate
portion connecting the distal portion the proximal
portion; the intermediate portion having a transverse
cross-section sized to fit within the smallest transverse
cross-section of the undercut hole in the workpiece; the
proximal end defining a substantially polygonal surface
sized to contain an axial projection of the transverse
cross-section of the intermediate portion; the proximal
portion tapering inwardly and distally from the proximal
end so as to smoothly mate with the intermediate portion;
the distal portion curving inwardly and distally from the
I5 intermediate portion to the distal end, and the distal
end defining a curved surface which smoothly mates with
the distal portion; the distal portion and the distal end
together defining a substantially U-shaped groove
extending from a first groove end adjacent the
intermediate portion and located in alignment with one
corner of the proximal end to a second groove end
adjacent the intermediate portion and located in
alignment with another corner of the proximal end; the
groove being sized to receive a length of the cord-like
material therein; a first bore extending from the first
groove end to the proximal end of anchor, parallel to the
longitudinal axis; a second bore extending from the
second groove end to the proximal end of the anchor,
parallel to the longitudinal axis; the first and second
bores being sized to receive a length of the cord-like
material therethrough; and a third bore extending into
the proximal end of the anchor adjacent to another corner
thereof, the third bore also being parallel to the
longitudinal axis and extending through at least the
proximal portion of the anchor.
In one form of the present invention, the
inserter comprises a handle containing a biasing element;
CA 02417170 2003-02-11
-
a drive rod having a rod longitudinal axis, a rod distal
end, a rod proximal end, and an axial length, the
proximal end of the drive rod being attached to the
handle; and a sleeve having a sleeve longitudinal axis,
a sleeve proximal end, a sleeve distal end, and an axial
length shorter than the axial length of the drive rod;
the sleeve being telescopically mounted co-axially over
the drive rod and in engagement with the handle and the
biasing element such that the sleeve is normally biased
toward a first position wherein the sleeve distal end is
located distally of the rod distal end so as to create an
open cavity adapted to receive and frir_tionally retain at
least a portion of the anchor, but may be moved
proximally along the drive rod against the biasing
15 element to a second position wherein the rod distal end
projects axially and distally from the sleeve distal end.
In one form of the present invention, the
method for forming an undercut bore in a workpiece
comprises (a) providing a drill for forming an undercut
hole in a workpiece, the drill comprising: a shaft
having a proximal end, a distal end and a first
longitudinal axis; a re-centering element attached to the
distal end of the shaft, the re-centering element
including a distally-tapering portion centered on a
second longitudinal axis parallel t.o, but laterally
spaced from, a projection of the first longitudinal axis;
a connecting member centered on the second longitudinal
axis, the connecting member having a proximal end and a
distal end, the connecting member extending distally from
the re-centering member and being attached at the
proximal end of the connecting member to the distally-
tapering portion such that the connecting member and the
distally-tapering portion together define a beveled
corner centered on the second axis; and a substantially
cylindrical drill head centered on an axial projection of
the first longitudinal axis, the drill head having a
proximal end, a distal cutting tip, an outer surface
CA 02417170 2003-02-11
defining cutting flute means extending between the distal
cutting tip and the drill head proximal end, and a
transverse cross-section larger than the transverse
cross-section of the connecting member; the proximal end
of the drill head being eccentr_i.cally attached to the
distal end of the connecting member; (b) engaging the
distal tip with the surface of the workpiece;
(c) rotating the drill on the first longitudinal axis
while urging the distal tip toward the workpiece so as to
form a substantially cylindrical bore in the workpiece
having a depth substantially equal to the axial length of
the drill head plus the axial length of the connecting
means; (d) further advancing the distal tip into the
workpiece such that the beveled corner engages the bore,
thereby shifting the axis of rotation of the drill head
from the first longitudinal axis toward the. second
longitudinal axis and causing the drill head to enlarge
the diameter of the bore below a depth substantially
equal to the axial length of the connecting means; arid
(2) removing the drill head and the connecting means from
the bore..
In one form of the present invention, the
method for attaching an object to a workpiece comprises
the steps of: providing a bore in the workpiece;
providing an elastically compressible anchor having a
longitudinal axis, a cross-section transverse to the
longitudinal axis larger than the transverse cross-
section of the bore adjacent the surface of the
workpiece, and means for attaching an object to the
anchor; axially inserting the anchor into the bore so as
to secure the anchor to the workpiece; and attaching the
object to the anchor.
In one form of the present invention, the
method for attaching a length of cord-like material
within an opening in a workpiece comprises the steps of:
(a)providing:
a length of cord-like material;
CA 02417170 2003-02-11
an anchor for securing a length of cord-
like material in the undercut hole in the workpiece, the
anchor comprising:
a body of resilient material including a
longitudinal axis, a distal end, a distal portion
adjacent to the distal end, a proximal end, a proximal .
portion adjacent to the proximal end, and an intermediate
portion connecting the distal portion to the proximal
portion;
the intermediate portion having a
transverse cross-section sized to fit within the smallest
transverse cross-section of the undercut hole in the
workpiece;
the proximal end defining a substantially
polygonal surface sized to contain an axial projection of
the transverse cross-section of the intermediate portion;
the proximal portion tapering inwardly and
distally from the proximal end so as to smoothly mate
with the intermediate portion;
the distal portion curving inwardly and
distally from the intermediate portion to the distal end,
and the distal end defining a curved surface which
smoothly mates with the distal portion;
the distal portion and the distal end
together defining a substantially U-shaped groove
extending from a first groove end adjacent the
intermediate portion and located in alignment with one
corner of the proximal end to a second groove end
adjacent the intermediate portion and located in
alignment with another corner of the proximal end;
the groove being sized to receive a length
of the cord-like material therein;
a first bore extending from the first
groove end to the proximal end of anchor, parallel to the
longitudinal axis;
a second bore extending from the second
groove end to the proximal end of the anchor, parallel to
CA 02417170 2003-02-11
_g_
the longitudinal axis;
the first and second bores being sized to
receive a length of the cord-like material therethrough;
and
a third bore extending into the proximal
end of the anchor adjacent to another corner thereof, the
third bore alsa being parallel to the longitudinal axis
and extending through at least the proximal portion of
the anchor; and
an inserter for deploying a compressible
anchor in the undercut hole in the workpiece, the
inserter comprising4
a handle containing a biasing element;
a drive rod having a rod longitudinal
axis, a rod distal end, a rod proximal end, and an axial
length, the proximal end of the drive rod being attached
to the handle; and
a sleeve having a sleeve longitudinal
axis, a sleeve proximal end, a sleeve distal end, and an
axial length shorter than the axial length of the drive
rod;
the sleeve being telescopically mounted
co-axially over the drive rod and in engagement with the
handle and the biasing element such that the sleeve is
normally biased toward a first position wherein the
sleeve distal end is located distally of the rod distal
end so as to create an open cavity adapted to receive and
frictionally retain at least a portion of the anchor, but
may be moved proximally along the drive rod against the
biasing element to a second position wherein the rod
distal end projects axially and distally from the sleeve
distal end;
(b) threading the length of cord-like material
distally through the first bore in the anchor, through
the groove in the anchor, and proximally through the
second bore in the anchor;
(c) with the inserter in the first position,
CA 02417170 2003-02-11
-zo-
inserting the anchor proximal and first into the cavity
at the distal end of the sleeve and retaining the anchor
in the cavity by a frictional fit;
(d) engaging the distal end of the sleeve with
the surface of the workpiece immediately surrounding the
undercut opening;
(e) exerting a driving force on the handle so
as to move the sleeve from its first position relative to
the drive rod to its second position relative to the
drive rod and to advance the distal end of the drive rod
into the opening pushing the anchor ahead of it, thereby
elastically deforming the anchor; and
(f) removing the drive rod from the opening
and the distal end of the sleeve from the surface of the
workpiece.
In another form of the present invention, the
method for attaching a length of cord--like material to a
workpiece comprises the steps of:
(a) providing:
a length of cord-like material;
a drill for forming an undercut hole in a
workpiece, the drill comprising:
a shaft having a proximal end, a distal
end and a first longitudinal axis;
a re-centering element attached to the
distal end of the shaft, the re-centering element
including a distally-tapering portion centered on a
second longitudinal axis parallel to, but laterally
spaced from, a projection of the first longitudinal axis;
a connecting member centered on the second
longitudinal axis, the connecting member having a
proximal end and a distal end, the connecting member
extending distally from the re-centering member and being
attached at the proximal end of the connecting member to
the distally-tapering portion such that the connecting
member and the distally-tapering portion together define
a beveled corner centered on the second axis; and
CA 02417170 2003-02-11
-11-
a substantially cylindrical drill head
centered on an axial projection of the first longitudinal
axis, the drill head having a proximal end, a distal
cutting tip, an outer surface defining cutting flute
means extending between the distal cutting tip and the
drill head proximal end, and a transverse cross-section
larger than the transverse cross-section of the
connecting member;
the proximal end of the drill head being
eccentrically attached to the distal end of the
connecting member;
an anchor for securing a length of cord-
like material in the undercut hole in the workpiece, the
anchor comprising:
25 a body of resilient material including a
longitudinal axis, a distal end, a distal portion
adjacent to the distal end, a proximal end, a proximal
portion adjacent to the proximal end, and an intermediate
portion connecting the distal portion to the proximal
portion;
the intermediate portion having a
transverse cross-section sized to fit within the smallest
transverse cross-section of the undercut hole in the
workpiece;
the proximal end defining a substantially
polygonal surface sized to contain an axial projection of
the transverse cross-section of the intermediate portion;
the proximal portion tapering inwardly and
distally from the proximal end so as to smoothly mate
with the intermediate portion;
the distal portion curving inwardly and
distally from the intermediate portion to the distal end,
and the distal end defining a curved surface which
smoothly mates with the distal portion;
the distal portion and the distal end
together defining a substantially U-shaped groove
extending from a first groove end adjacent the
CA 02417170 2003-02-11
-12-
intermediate portion and located in alignment with one
corner of the proximal end to a second groove end
adjacent the intermediate portion and located in
alignment with another corner of the proximal end;
the groove being sized to receive a length
of the cord-like material therein;
a first bore extending from the first
groove end to the proximal end of anchor, parallel to the
longitudinal axis;
a second bore extending from the second
groove end to the proximal end of the anchor, parallel to
the longitudinal axis;
the first and second bores being sized to
receive a length of the cord-like material therethrough;
and
a third bore extending into the proximal
end of the anchor adjacent to another corner thereof, the
third bore also being parallel to the longitudinal axis
and extending through at least the proximal portion of
the anchor; and
an inserter for deploying a compressible
anchor in the undercut hole in the workpiece, the
inserter comprising:
a handle containing a biasing element;
a drive rod having a rod longitudinal
axis, a rod distal end, a rod proximal end, and an axial
length, the proximal end of the drive rod being attached
to the handle; and
a sleeve having a sleeve longitudinal
axis, a sleeve proximal end, a sleeve distal end, and an
axial length shorter than the axial length of the drive
rod;
the sleeve being telescopically mounted
coaxially over the drive rod and in engagement with the
handle and the biasing element such that the sleeve is
normally biased toward a first position wherein the
sleeve distal end is located distally of the rod distal
CA 02417170 2003-02-11
-13-
end so as to create an open cavity adapted to receive and
frictionally retain at least a portion of the anchor, but
may be moved proximally along the drive rod against the
biasing element to a second position wherein the rod
distal end projects axially and distally from the sleeve
distal end;
(b) forming an undercut hole in the workpiece
with the drill by (1) engaging the distal tip of the
drill head with the surface of the workpiece, (2)
rotating the drill on the first axis while advancing the
distal tip of the drill head into the workpiece to a
depth equal to the axial length of the drill head plus
the axial length of the connecting member, so as to form
a substantially cylindrical bore in the workpiece, (3)
advancing the distal tip further into the workpiece so as
to force the beveled corner into the hole thereby causing
the axis of rotation of the drill head to shift from the
first longitudj_nal~axis toward the second longitudinal
axis and the drill head to radially enlarge the inner
portion of the hole, and (4) removing the drill head and
the connecting member from the bore through the outer,
unenlarged portion of thereof;
(c) threading the length of cord-like material
distally through the first bore in the anchor, through
the groove in the anchor, and proximally through the
second bore in the anchor;
(d) with the inserter in the first position,
inserting the anchor proximal and first into the cavity
at the distal end of the sleeve and retaining the anchor
in the cavity by a frictional fit;
(e) engaging the distal end of the sleeve with
the surface of the workpiece immediately surrounding the
undercut hole;
(f) exerting a driving force on the handle so
as to move the sleeve from its first position relative to
the drive rod to its second position relative to the
drive rod and to advance the distal end of the drive rod
CA 02417170 2003-02-11
-1~-
into the undercut hole pushing the anchor ahead of it,
thereby elastically deforming the anchor as i-t passes
through the non-enlarged portion of the undercut hole and
allowing the anchor to expand to its original shape upon
the completion of its entry into 'the enlarged portion of
the undercut hole; and
(g) removing the drive rod from the undercut
hole and the distal end of the sleeve from the surface of
the workpiecee
According to another aspect of the invention, a
system for attaching an object to a human body, the
system comprises:
a drill for forming an undercut hole in a human
body, the drill comprises:
a shaft having a proximal end, a distal end and
a first longitudinal axis;
a re-centering element attached to the distal
end of the shaft,, the re-centering element including a
distally-tapering portion centered on a second
longitudinal axis parallel to, but laterally spaced from,
a projection of the first longitudinal axis;
a connecting member centered on the second
longitudinal axis, the connecting member having a
proximal end and a distal end, the connecting member
extending distally from the re-centering member and being
attached at the proximal end of the connecting member to
the distally-tapering portion such that the connecting
member and the distally-tapering portion together define
a beveled corner. centered on the second axis; and
a substantially cylindrical drill head centered
on an axial cross-section of the first longitudinal axis,
the drill head having a proximal end, a distal cutting
tip, an outer surface defining cutting flute means
extending betweer. the distal cutting tip and the head
CA 02417170 2003-02-11
-14a-
proximal end, and a transverse cross-section larger than
the transverse cross-section of the connecting member;
the proximal end of the drill head
being eccentrically attached to the distal end of the
connecting member;
an anchor for securing a length of cord-like
material in the undercut hole in the human body, the
anchor compriseso
a body of resilient material. including a
longitudinal axis, a distal end, a distal portion
adjacent to the distal end, a proximal end, a proximal
portion adjacent to the proximal end, and an intermediate
portion connecting the distal portion to the proximal
portion;
the intermediate portion having a transverse
cross-section sized to fit within the smallest transverse
cross-section of the undercut hole in the human body;
the proximal end defining a substantially
polygonal surface sized to contain an axial projection
of the transverse cross-section of the intermediate
portion;
the proximal portion tapering inwardly and
distally from the proximal end so as to smoothly mate
with the intermediate portion;
the distal portion curving inwardly and distally
from the intermediate portion to 'the distal end, and the
distal end defining a curved surface which smoothly mates
with the distal portion;
the distal portion and the distal end
together defining a substantially U-shaped groove
extending from a first groove end adjacent the
intermediate portion and located in alignment with one
corner of the proximal end to a second groove end
CA 02417170 2003-02-11
-14b-
adjacent the intermediate portion and located in
alignment with another corner of the proximal-end;
the groove being sized to receive a length of
the cord-like material therein;
a first bore extending from the first groove
end to the proximal end of anchor, parallel to the
longitudinal axis;
a second bore extending from the second groove
end to the proximal end of the anchor, parallel to the
longitudinal axis;
the first and second bores being sized to
receive a length of the cord-like material therethrough;
and
a third bare extending into the proximal end
of the anchor adjacent to another corner thereof, the
third bore also being parallel to the longitudinal axis
and extending through at least the proximal portion of
the anchor; and
an inserter for deploying a compressible anchor
in the undercut hole in the workpiece, the inserter
comprises:
a handle containing a biasing element;
a drive rod having a rod longitudinal axis, a
rod distal end, a rod proximal end, and an axial length;
the proximal end of the drive rod being attached to the
handle; and
a sleeve having a sleeve longitudinal axis, a
sleeve proximal end, a sleeve distal end, and an axial
length shorter than the axial length of the drive rod;
the sleeve being telescopically mounted
coaxially over the drive rod and in engagement with the
handle and the biasing element such that the sleeve is
normally biased toward a first position wherein the
sleeve distal end is located distally of the rod distal
CA 02417170 2003-02-11
-14C-
end so as to create an open cavity adapted to receive and
frictionally retain at least a portion. of the. anchor, but
may be moved proximally along the drive rod against the
biasing element to a second position wherein the rod
distal end projects axially and distally from the sleeve
distal end.
According to anather aspect of the invention, a
method for forming an undercut bore in a bone of the
human body, the method comprises:
(a) providing a drill for forming an undercut
hole in the bone, the drill comprises
a shaft having a proximal end, a distal end and
a first longitudinal axis;
a re-centering element attached to the distal
end of the shaft, the re-centering element including a
distally-tapering portion centered on a second
longitudinal axis parallel to, but laterally spaced from,
a projection of the first longitudinal axis;
a connecting member centered on the second
longitudinal axis, the connecting member having a
proximal end and a distal end, the connecting member
extending distally from the re-centering member and being
attached at the proximal end of the connecting member to
the distally-tapering portion such that the connecting
member and the distally-tapering portion together define
a beveled corner centered on the second axis; and
a substantially cylindrical drill head centered
on an axial projection of the first longitudinal axis,
the drill head having a proximal e:nd, a. distal cutting
3D tip, an outer surface defining cutting flute means
extending between the distal cutting tip and the drill
head proximal end, and a transverse cross-section larger
than the transverse cross-section of the connecting'
member;
CA 02417170 2003-02-11
-14d-
the proximal end of the drill head being
eccentrically attached to the distal end of the
connecting member;
(b) engaging the distal tip with the surface
of the bone;
(c) rotating the drill on the first
longitudinal axis while urging the distal tip toward the
bone so as to form a substantially cylindrical bore in
the bone having a depth substantially equa-1 to the axial
length of the drill head plus the axial length of the
connecting means;
(d) further advancing the distal tip into
the bone such that the beveled corner engages the bore,
thereby shifting the axis of rotation of the drill head
form the first longitudinal axis toward the second
longitudinal axis and causing the drill head to enlarge
the diameter of the bore below a depth substantially
equal to the axial length of the conne<aing means; and
(e) removing the_drill head and the
connecting means from the bore
According to another aspect of the invention, a
method for attaching an object to a bone of the human
body, the method comprises the steps of:
providing a bore in the bone!
providing an elastically compressible anchor
having a longitudinal axis, a cross-section transverse to
the.longitudinal axis larger than the transverse cross-
section of the bore adjacent the surface of the bone, and
means for attaching an object to the anchor;
axially inserting the anchor into the bore so
as to secure the anchor to the bone; and
attaching the object to the anchor.
CA 02417170 2003-02-11
14e
According to a further aspect of the invention,
A method for attaching a length of card-like material
within an undercut hole in a bone of a human, said method
- ~ comprises the steps of
(a) providing;
a length of cord-like material;
a drill for forming the undercut hole
in said bone, said drill comprising;
a shaft having a proximal end, a
distal end and a first longitudinal axis;
a re-centering element attached to
said distal end of said shaft, said re-centering element
including a distally-tapering portion centered on a
second longitudinal axis parallel to, but laterally
spaced from, a projection of said :First longitudinal
axis;
a connecting member centered on said
second longitudinal axis, said connecting member having a
proximal end and a distal end, said connecting member
.extending distally from said re-centering member and
being attached at said proximal end of said connecting
member to said distally-tapering portion such that said
connecting member and said distally-tapering portion
together define a beveled corner centered on said second
axis; and
a Substantially cylindrical drill
head centered on an axial projection of said first
longitudinal axis, said drill head having a proximal end,
a distal cutting tip, an outer surface defining cutting
flute means extending between said distal cutting tip and
said drill head proximal end,, and a transverse cross-
section larger than the transverse cross-section of said
connecting member;
said proximal end of said drill head
CA 02417170 2003-02-11
14f
being eccentrically attached to said distal end of said
connecting member;
an anchor for securing a length of
cord-like material in the 'undercut hole in said bone,
said anchor comprising;
a body of resilient material
including a longitudinal axis, a distal end, a distal
portion adjacent to said distal end, a proximal end, a
proximal portion adjacent to said proximal end, and an
intermediate portion connecting said distal portion to
said proximal portion;
said intermediate portion having a
transverse cross-section sized to fit within the smallest
transverse cross-section of said undercut hole in said
bone ;
said proximal end defining a
substantially polygonal surface sized to contain an axial
projection of said transverse cross-section of said
intermediate portion;
said proximal portion tapering
inwardly and distally from said proximal end so as to
smoothly mate with said intermediate portion;
said distal portion curving inwardly
and distally from said intermediate portion to said
distal end, and said distal end defining a curved surface
which smoothly mates with said distal portion;
said distal portion and said distal
end together defining a substantially U-shaped groove
extending from a first groove end adjacent said
intermediate portion and located in alignment with one
corner of said proximal end to a second groove end
adjacent said intermediate portion and located in
alignment with another corner of said proximal end;
said groove being sized to receive a
CA 02417170 2003-02-11
14g
length of the cord-~_ike material
therein;
a first bore extending from said
first groove end to said proximal end of anchor, parallel
to said longitudinal axis;
a second bore extending from said
second groove end to said proximal end of said anchor,
parallel to said longitudinal axis;
said first and second bores being
sized to receive a length of the cord-like material
therethrough; and
a third bore extending into said
proximal end of said anchor adjacent to another corner
thereof, said third bore also being parallel to said
longitudinal axis and extending through at least the
proximal portion of said anchor; and
an inserter for deploying a
compressible anchor in the undercut hole in said bone,
said inserter comprising:
a handle containing a biasing
element;
a drive rod having a rod longitudinal
axis, a rod distal end, a rod proximal end, and an axial
length, said proximal end of said drive rod being
attached to said handle; and
a sleeve having a sleeve longitudinal
axis, a sleeve proximal end, a sleeve distal end, and an
axial length shorter than said axial length of said drive
rod;
said sleeve being telescopically
mounted co-axially over said drive rod and in engagement
with said handle and said biasing element such that said
sleeve is normally biased toward a first position wherein -
said sleeve distal end is located distally of said rod
CA 02417170 2003-02-11
14h
distal end so as to create a cavity adapted to receive
and fractionally retain at lease a portion of the anchor,
but may be moved proximally along said drive rod against
said biasing element to a second position wherein said
rod distal end projects axially and distally from said
sleeve distal end;
(b) threading said length of cord-like
material distally through said first bore in said anchor,
through said groove in said anchor, and proximally
through said second bore in said anchor;
(c) with said inserter in said first
position, inserting said anchor proximal and first into
said cavity at said distal end of said sleeve and
retaining the anchor in said cavity by a frictional fit;
(d) engaging said distal end of said
sleeve with a surface of said bone immediately
surrounding said undercut hole;
(e) exerting a driving force or said
handle so as to move said sleeve from its first position
relative to said drive rod to its second position
relative to said drive rod and to advance said distal end
of said drive rod into said undercut hole pushing said
anchor ahead of it, thereby elastically deforming said
anchor as it passes through said non-enlarged portion of
said undercut hole and allowing said anchor to expand to
its original shape upon the completion of its entry into
the enlarged portion of said undercut hole; and
(f) removing said drive rod from said
undercut hole and said distal end of said sleeve from
~0 said surface at said bone.
According to a further aspect of the invention,
there is provided an inserter for deploying a
compressible anchor in an undercut hole in a bone, said
inserter comprising:
CA 02417170 2003-02-11
14i
a handle containing a biasing element;
a drive rod having a rod longitudinal axis, a
rod distal end, a rod proximal end, and an axial length,
said proximal end of said drive rod being attached to
said handle; and
a sleeve having a sleeve longitudinal axis, a
sleeve proximal end, a sleeve distal end, and an axial
length shorter than said axial length of said drive rod;
said sleeve being telescopically mounted
coaxially over said drive rod and ira engagement with said
handle and said biasing element such that said sleeve is
normally biased toward a first position wherein said
sleeve distal end is located distally of said rod distal
end so as to create an open cavity adapted to receive and
fractionally retain at least a portion of the anchor, but
may be moved proximally along said drive rod against said
biasing element to a second position. wherein said rod
distal and projects axially and distally from said sleeve
distal end.
Brief Description of The Drawings
These and other objects anal features of the
present invention will be more fully disclosed or
rendered obvious by the following detailed description of
the preferred embodiments of the invention, which are to
be considered together with the accompanying drawings
wherein like numbers refer to like parts, and further
wherein:
Fig. 1 is a perspective view of a drill formed
in accordance with the present invention;
Fig. 2 is a perspective view of an anchor
formed in accordance with the present invention, with a
cord-like element attached thereto;
Fig. 3 is a perspective view of an inserter
device for deploying the anchor shown in Fig. 2;
CA 02417170 2003-02-11
14j
Figs. 4-7 are detailed views of the drill shown
in Fig. l;
Figs. 8-10 show the drill of Fig. 1 forming an
undercut hole in a workpiece;
Figs. 11-15 are detailed views of the anchor
shown in Fig. 2;
CA 02417170 2003-02-11
-15-
Figs. 16-27 are detailed views showing various
aspects of the inserter device of Fig. 3; and
Figs. 28-33 show the inserter device of Fig. 3
deploying the anchor of Fig. 2 in a workpiece.
Detailed Description Of The Preferred Embodiments
As discussed above, the present invention
comprises a novel system and method for anchoring a
suture or other cord-like element to a bone or other
workpiece. More particularly, the novel system.includes
a drill 100 generally shown in Fig. l, an anchor 300
generally shown in Fig. 2, and an anchor insertion device
S00 generally shown in Fig. 3. The method generally
includes the steps of forming an undercut hole in the
workpiece and locating an anchor (with a cord-like
element attached thereto) securely within the hole, as
will be discussed in detail below.
Referring specifically to Figs. 1 and 4-7, it
will be seen that drill 100 includes a shaft 105 and a
drill head 110.
Shaft 105 has a shaft distal end 112, a shaft
proximal end 115, a central longitudinal axis 195, and a
re-centering element 12S attached to shaft distal end
112. The shaft proximal end 115 terminates in a portion
130 which is configured to be received in the chuck of a
power drill or the like (not shown). Alternatively, in
the event that drill 100 is to be hand driven, rather
than power driven, portion 130 may be configured in the
form of a handle.
Re-centering element 125 includes a central,
substantially cylindrical portion 135 having a
longitudinal axis aligned with shaft longitudinal axis
195, and a proximally-tapering portion 145 attached to
shaft distal end 112 and having a longitudinal axis
aligned with shaft longitudinal axis 195. Re-centering
element 125 also comprises a distally-tapering portion
CA 02417170 2003-02-11
-16-
155 attached to a distally-extending connecting portion
160. Distally-tapering portion 155 and distally-
extending connecting portion 160 are centered about a
longitudinal axis 120. Longitudinal axis 120 is
laterally offset from longitudinal axis 195 in the manner
shown in Fig. 6. The angle of taper of proximally-
tapering portion 145 relative to longitudinal axis 195 is
substantially smaller than the angle of taper of
distally-tapering portion 155 relative to longitudinal
axis 120. Distally-tapering portion 155 and connecting'
portion 160 together define a beveled corner 170 at their
intersection. :Beveled corner 170 is also centered about
longitudinal axis 120, which longitudinal axis is
laterally offset from the above-mentioned longitudinal
' 15 axis 195. Preferably beveled corner 170 comprises a
radius. Re-centering element 125 also preferably defines
a cutting flute 175 which extends from. shaft distal end
112 to connecting portion 160, i.e., through proximally-
tapering portion 145, cylindrical portion 135, distally-
tapering portion 155 and beveled corner 170.
Drill head 110 is connected to the distal end
of connecting portion 160. Drill head 110 has a drill
head proximal end 180 and a drill head distal end 190.
Drill head 110 is centered about the aforementioned
longitudinal axis 195. Drill head 110 also includes an
outer surface 200 defining a distal cutting tip 205 at
drill head distal end 190, and at least one, and
preferably a pair, of cutting flutes 210 extending from
cutting tip 205 to drill head proximal end 180.
The diameter of connecting portion 160 is
selected to be smaller than the diameter of drill head
110, such that when drill head. 110 is attached to
connecting portion 160, an edge 220 of drill head 110,
located between an adjacent pair of Cutting flutes 210,
is located on an axial projection of the aforementioned
cutting flute 175.
As will hereinafter be. described in greater
CA 02417170 2003-02-11
- 1 7 -
detail, the foregoing drill 100 may be conveniently used
to form an undercut hole in a piece of bone or other
workpiece. More specifically, the distal cutting tip 205
may be placed against a surface 221 of the workpiece 225
(Fig. 8) , and the drill head 100 may be rotated on its
longitudinal axis 195. This will cause drill head 110 to
form an initial bore 227 in the workpiece (Fig. 9). then
this bore 227 reaches a depth equal to the axial length
of drill head 110 plus the axial. length of connecting
portion 160, however, the beveled corner 170 will engage
the edge 226 of the bore 227 at the surface 221 of the
workpiece. In this respect it is to be appreciated that
the longitudinal axis 120 of the beveled corner 170 is
laterally offset from the shaft's longitudinal axis 195.
Accordingly, as the drill head continues to advance into
the workpiece, the axis of rotation of drill head 110
will shift laterally from the shaft°s longitudinal axis
195 to the beveled corner°s longitudinal axis 120. The
effect will be to gradually force the movement of drill
head 110 laterally so as to undercut the workpiece and
. form a second bore 228 at a depth substantially equal to
the axial length of connecting portion 160 plus beveled
corner 170 (Fig. 10). It should also be appreciated that
as this occurs, cutting flute 175 of the re-centering
element 125 will form a countersunk portion at the
opening of bore 227.
Referring next to Figs. 2 and 11-15, it will be
seen that the anchor 300 comprises a block of material
having natural resiliency. This block comprises a body
305 which includes a dista:i end 310, a distal portion 325
adjacent to the distal end 310, a proximal end 326, a
proximal portion 327 adjacent to the :proximal end 326,
and an intermediate portion 330 coranecting distal portion
325 to proximal portion 327.
More particularly, intermediate portion 330 has
a substantially cylindr~_cal cross-section having a
diameter slightly smaller than the diameter of drill head
CA 02417170 2003-02-11
-18-
110. The distal portion 325 curves inwardly from
intermediate portion 330 to curved. distal end 310.
Further, distal end 310 and distal portion 325 together
define a groove 335 (Fig. 11) which extends from a first
5 end 340 (Fig. 13) (adjacent one side 345 of intermediate
portion 330), across distal end 310 to a second end 355
(adjacent another side 360 of intermediate portion 330).
Groove 335 is adapted to receive a suture or other cord
like element :365 (Fig. 2) bent in a substantially U
shaped configuration.
Bores 370, 375 (Fig. 12) extend from groove
ends 340 and 355, respectively, to proximal end 326,
parallel to the longitudinal axis 380 (Fig. 13) of body
305. Bores 37U and 375 each have a cross-sectional size
and shape adapted to accommodate the suture or other
cord-like element 365. Hence, the suture or other cord-
like element 365 may be threaded through bore 370, across
groove 335 and back through bore 375 (see Fig. 2).
Preferably bores 370 and 375, and the suture or other
cord-like element 365, are sized so that the suture or
other cord-like element does not completely fill, in a
diametrical sense, bores 370 and 375.
The proximal end 326 of the anchor is
substantially rectangular in shape, such that an axial
projection of the circular cross-section of intermediate
portion 330 will fit within the boundaries of rectangular
proximal end 326. Accordingly, it will be understood
that proximal portion 327 of body 305 tapers inwardly
from corners 385, 390, 395 and 400 (Fig. 14) of proximal
end 326, respectively, so as to smoothly mate with
intermediate portion 330. In view of this construction,
suture anchor 300 essentially has four projections or
lobes projecting radially beyond the circumference of the
anchor's intermediate portion 330. Preferably the walls
extending between corners 385, 390, 395 and 400 are
curved slightly so as to form curved lobes projecting
radially beyond the anchor's intermediate portion 330.
CA 02417170 2003-02-11
-19-
In one preferred form of the invention, each of the walls
extending between the corners 385, 390, 395 and 400
comprise a radius.
The openings of bores 370 and 375 onto proximal
end 326 are located adjacent to opposite corners 390 and
400, respectively. Further, bores 415 and 420 extend
into proximal end 326 adjacent to opposite corners 385
and 395, respectively. Bores 415 and 420 need not
necessarily extend all the way through body 305. Thus,
as shown in the drawings, bores 415 and 420 extend from
the proximal end 326 of body 305 parallel to one another,
and parallel to the anchor's longitudinal axis 380, to
closed ends located in intermediate portion 330 of body
305.
Since the suture or other cord-like element
365, extending through bores 370 and 375, does not
completely fill bores 370 and 375, and since the suture
or other cord-like element 365 is generally formed of a
woven material which may be compressed, it will be. seen
that the natural plasticity of the anchor material,
together with longitudinal bores 3?0, 375, 415 and 420,1
allow the proximal, generally rectangular cross-section
of the body to be substantially elastically compressed.
Accordingly, anchor body 305 may be easily compressibly
deformed so as to fit through the outer portion 227 of
the undercut hole formed by the drill 100 in workpiece
225, and thereafter slowed to elastically expand to its
normal shape within the undercut portion 228 of the hole
so as to securely anchor the suture or other cord-like
element 365 to the workpiece. By placing one of the
holes 3'70, 375, 415 and 420 next to each of the corners
385, 390, 395 and 400, space is provided within the body
of the anchor for the corners to deflect radially
inwardly during anchor insertion. This helps prevent the
anchor from deforming longitudinally during anchor
insertion.
By way of example but not limitation, anchor
CA 02417170 2003-02-11
-20-
300 may be formed out of a non-absorbable polymer such as
polysulfone or an absorbable polymer such as polylactic
acid (PLA).
A specialized inserter device 500 has been
found to be particularly useful in the emplacement of an
anchor as just described into an undercut hole in a
workpiece. This inserter device 500 is generally shown
in Fig. 3, and more particularly illustrated in Figs. 16
27.
Inserter device 500 includes a handle 505
(Figs. 3 and 16-18), a drive rod 510 (Figs. 3 and 19-22)
a sleeve 515 (Figs. 3 and 23-27), and biasing means 520
(Fig. 3).
More specifically, as representatively shown in
Figs. 16-18, the handle 505 may conveniently be made in
two identical halves 525. In its assembled form, handle
505 defines a drive rod mounting cavity 535, a
sleeve/biasing means mounting cavity 540, and a
sleeve/drive rod exit portal 545.
The drive rod 510, shown particularly in Figs.
19-22, includes a shaft 550 having a distal end 555 and
a proximal end 560, an enlarged proximal portion 565
attached to the proximal end 560, and an elongated tip
portion 570 attached to the distal end 555. The enlarged
proximal portion 565 sized to fixedly engage the drive
rod mounting cavity 535 in handle 505, with the shaft 550
extending outwardly therefrom through sleeve/biasing
means mounting cavity 540 and exit portal 545. The
elongated tip portion 570 has a smaller diametric cross-
section than shaft 550, and shaft 550 and elongated tip
portion 570 have a common longitudinal axis 575.
Further, elongated tip portion 570 defines a pair of
opposing longitudinal grooves 580 (Fig. 22) in its outer
surface 585 which preferably extend along substantially
the entire length of elongated t:ip portion 570. The
grooves 580 are sized to receive the suture or other
cord-like element 365 threaded through anchor body 305.
CA 02417170 2003-02-11
-21-
The biasing means 520, in the preferred
embodiment of the invention, is a coil spring. The coil
spring is located in sleeve/biasing means mounting cavity
540, co-axially surrounding shaft 550 of drive rod 510,
and in engagement with the proximal shoulder S90 (Fig.
16) of cavity 540.
The sleeve 515, shown particularly in Figs. 23-
27, includes an elongated, hollow tubular member 595, a
proximal end 600, a radially-extending flange 605
surrounding the tubular member at its proximal end, a
distal end 610, and a reduced diameter portion 615
adjacent to its distal end. The reduced diameter portion
615 defines a pair of opposing longitudinal slots 620
(Fig. 27) extending proximally from the distal end 610
for substantially the entire length o:f reduced diameter
portion 615. The transverse width of slots 620 is such
that the suture or other cord-like element 365 may be
slidably received therein.
The sleeve 515 is disposed in telescoping
relation over the drive rod shaft 550, with the sleeve°s
flange 605 located in the sleeve/biasing means mounting
cavity 540, between the distal end of Spring 520 and the
forward end surface 621 (Fige 16) of cavity 540, such
that tubular member 595 is slidingly received in portal
545.
Thus it will be understood that handle 505 and
drive rod 510 together form a substantially integral
subassembly, with sleeve 515 adapted to reciprocate
relative to the drive rod. In this regard it will be
understood that the relative lengths of drive rod shaft
550 and tubular member 595 are selected such that, in
their "normal" (i.e., with tubular rn.ember 595 in its
outwardly-biased) position, the sleeve's reduced diameter
portion 615 is disposed distally of the distal end of the
tip portion 570 of the drive rod 510. This defines a
cavity in the distal end of the inserter device 500~into
which the anchor 300 may be placed and maintained by a
CA 02417170 2003-02-11
-22-
frictional fit. At the same time,. the sleeve's slots 620
permit a suture or other cord-like element 365 attached
to the anchor to exit the sleeve.
Accordingly, once the undercut hole in the
workpiece has been formed by drill 100, the inserter
device 500, with anchor 300 located within its distal end'
and with the suture or other cord-like element 365
threaded through the anchor and extending outwardly
through the slots 620, may be used to insert the anchor
into the undercut portion of the hole. More
particularly, the distal end 610 of the sleeve may be
brought into engagement with the surface 221 of the
workpiece surrounding the upper. bore 226 (Figs. 28-31).
Then, by pushing downwardly on the handle; the biasing
force tending to hold the sleeve i.n its extended position
may be overcome, thereby allowing the tip portion of the
drive rod to engage the anchor and to drive it through
upper bore 227 and down into the undez~cut portion 228 of
the hole (Figs. 32 and 33).
In so doing, the free ends of the suture or
other cord-like element 365 enter the grooves 580 in
drive rod 510 so as to avoid being crushed or broken
during anchor deployment into the workpiece hole. At the
same time, the resilient nature of anchor 300, in concert
with the longitudinal bores 370, 375, 415 and 420 formed
therein, allow the anchor to elastically collapse
inwardly on itself far enough to pass through the smaller
portion 227 of the :hole and then re-expand to its normal
shape at the undercut portion 228 of the workpiece hole,
thereby locking the anchor secrecy in the workpiece.
The foregoing concepts will be more fully
understood by the following description of ,an example of
the system and method of the present invention in a
medical context.
3S Looking now to Figs. 8-10 and 28-33, an example
of the use of the invention to attach a length of suture
365 to a bone 225 is shown. In this context it should be
CA 02417170 2003-02-11
-23-
understood that the nature of bone is such that the
formation of an undercut hole is not. always necessary.
This is because some bones have natural internal cavities
(e. g., the head of the tibia, the hu.meral head, etc.),
and other types of bone have soft cancellous interiors
distal to the outer cortical layer. In such a situation,
an ordinary single-diameter bore may be formed in the
bone. For the sake of the present description, however,
it will be assumed that an undercut hole will be formed
10 in the bone. With this understanding in mind, the method
of the present invention may include the following steps.
First, an undercut hole is formed in the bone
225 using a drill 100 substantially as described above.
Specifically, the distal cutting tip 205 of the drill
head 110 is placed against the l.ocat.ion on the surface
221 of bone 225 where it is desired to attach suture 365
(Fig. 8). The drill head 110 is then rotated about its
longitudinal axis 195 while being urged axially toward
the bone so as to cut into the bone (Fig. 9). This
causes the drill head 110 to form a substantially
cylindrical hole 227 in the bone.
Once the depth of the hole in the bone reaches
a depth equal to the axial length of the drill head 110
plus the axial length of the connecting portion 160, the
beveled corner 170 will engage the outer edge 226 of the
hole. Thereafter, as the drill head is advanced further
into the bone, its axis of rotation will be gradually
shifted from longitudinal axis 195 to the longitudinal
axis 120 by the tendency of the beveled corner 170 to
center itself relative to the outer edge 226 of the hole.
At the same time, the cutting flute 175 of re-centering
element 125 will engage the outer edge 226 of the bone
hole. The result of this is that the drill head 110 will
gradually shift laterally so as to increase the diameter
of the hole at a depth equal to the axial length of the
connecting portion 160, while the cutting flute 175
countersinks the outer end of the hole. Thus, once the
CA 02417170 2003-02-11
-24-
depth of the hole is equal to the axial length of the
drill head 110 plus the connecting portion 160 plus the
axial length of the beveled corner 170, the hole will
have an outer portion 227 (Fig. 10) having a first
diameter and an inner portion 228 having a second
diameter larger than the first diameter.
The rotation of the drill 100 is then stopped
and the shaft 105 is manipulated so as to align drill
head 110 with the outer portion 227 of the hole. The
drill head 110 may then be withdrawn from the hole.
A length of suture 365 is then threaded
distally through bore 370 of anchor 300, across groove
335, and then proximally back through bore 375. The
resulting anchor/suture assembly is then inserted,
proximal end first, into the reduced diameter portion 615
of sleeve 515, with the free ends of suture 365 extending
outwardly through slots 620. The anchor is held in this
position by a friction fit. In this condition, the
resulting inserter/anchor assembly is ready for use in
deploying the anchor into the undercut portion of the
bone hole.
If desired, the aforementioned inserter/anchor
assembly may be pre-assembled at the time of manufacture
and then packaged in a sterile package, with the sterile
package being opened in the operating room at the time of
use.
Anchor 300 is deployed in the bone hole by
bringing the distal end of sleeve 515 into engagement
with the surface of the bone adjacent the hole (Figs. 28-
31). With the sleeve so positioned, a driving force is
exerted distally on handle 505. Since the sleeve is
fixed relative to the boneY this driving force causes the
sleeve 515 to slide proximally in cavity 540, against the
biasing spring 520, and forces the elongated tip portion
570 of drive rod 510 into the hole, pushing anchor 300
ahead of it (Fig. 32 and 33).
As mentioned previously, the diameter of outer
CA 02417170 2003-02-11
-25-
portion 227 of the bcne hole is only slightly larger than
the diameter o:E the intermediate portion 330 of anchor
300, and the proximal end 326 of anchor 300 has a
generally rectangular shape large enough to contain an
axial projection of intermediate portion 330. Hence, as
the tapered distal portion 325, and intermediate portion
330, of anchor 300 enter the bone hole, they tend to
align the anchor 300 with the hole. Thereafter, as drive
rod 510 continues to force anchor 300 into the hole, the
proximal portion of the anchor is distorted (i.e.,
compressed) inwardly so as to fit within the outer
portion 227 of the hole . This is made possible by the
resilience of the material used to form anchor 300, and
by the presence of bores 370, 375, 415 and 420 adjacent
to the four co:rners of the proximal portion of anchor
300.
More specifically, bores 415 and 420 are empty
and extend through the proximal portion of anchor 300
into the intermediate portion thereof. This helps allow
the proximal portion of anchor 300 to compress inwardly.
Bores 370 and 375, on the other hand, are not empty, but
rather contain suture 365. Nevertheless, since bores 370
and 375 are larger in diameter than suture 365, and since
the suture is generally formed out of a woven material
such that it may be radially compressed, bores 370 and
375 also help allow the proximal portion of the anchor to
compress inwardly.
Once the proximal end of the anchor passes
through the outer portion 227 of the hole, and into inner
portion 228, the proximal portion of the anchor
elastically returns to its original shape. Therefore,
since the original shape of the anchor is too large to
pass through the outer portion 227 of the bone hole, the
anchor effectively and securely anchors the suture within
the bone. Thereafter, inserter 500 may be removed,
leaving the free ends of suture 365 extending out of the
hole. This suture may then be used to attach tissue (or
CA 02417170 2003-02-11
-26-
some other object to the bone).
In the above regard, :it is desirable that
(a) the drive rod 510 exert force against as much of the
proximal end of the anchor as possible, and (b) the
suture not be crushed or damaged during the anchor
insertion operation. The exertion of the driving force
against as much of the proximal end of the anchor as
possible helps keep the anchor from deviating from the
longitudinal axis of the outer portiori 227 of the hole
during deployment. Hence, each of the corners of the.
large proximal end of the anchor will tend to deflect
substantially equally inwardly, and the anchor will not
tend to twist and bind in the outer portion 227 of the
hole during insertion. To accomplish t~::is, the elongated
tip of the drive rod typically has a transverse cross-
section of the same shape, but slightly smaller than, the
transverse cross-section of the outer portion 227 of the
hole. However, in order to protect the sutures, the
elongated tip portion of the drive rod also has a pair of
opposing grooves 580 in its outer surface. These grooves
are sized to receive the free ends of the suture
extending from the anchor while the elongated tip of the
drive rod is located within the outer portion of the bone
hole.
In the foregoing description of anchor 300, the
proximal end 326 of the anchor is described as being
substantially rectangular, with four corners 385, 390,
395 and 400, and with one of the bores 370, 375, 415 and
420 being positioned next to. one of the corners 385, 390,
395 and 400. However, the proximal end 326 of anchor 300
could also be formed with some other polygonal shape,
e.g., substantially triangular, in which case only three
corners would be provided, and only one hole 415, 420
would be provided, in addition to the two suture holes
370, 375. Alternatively, the proxz_mal end 326 of anchor
300 could be formed with a pentagonal shape, i.e.,~ with
five corners, in which case three holes 415, 420 would be
CA 02417170 2003-02-11
-27-
provided, in addition to the two suture holes 370, 375;
or the proximal end 326 of anchor 300 could be formed
with a hexagonal shape, in which case four holes 415, 420
would be provided, in addition to the two suture holes
370, 375, etc. Preferably there are exactly as many
holes 370, 375, 415 and 420 as there are corners to the
proximal end 326 of anchor 300, with one hole aligned
with each corner. In this way, appropriate space will be
provided within the body of the anchor, into which the
corners may radially deflect during insertion, so as to
keep the body of the anchor from permanently deforming
longitudinally during deployment.
It is also anticipated that the proximal end
326 of anchor 300 could be formed with a non-polygonal
shape, e.g., circular or elliptical, in which case an
appropriate number of holes 415, 420 are formed in the
anchor in addition to the two suture hales 370~ 375.
It should also be appreciated that cutting
flute 175 might be omitted from drill 100 if desired.'
Furthermore, it should be appreciated that, if
desired, drill 100 might be removed from the bone hole
while still rotating.
It should also be appreciated that the undercut
hole might be farmed in the bone or. other workpiece using
apparatus other than drill 100.
Also, the anchor 300 might be set in the bone
or other workpiece using apparatus other than inserter
device 500.
Having thus described an illustrative preferred
embodiment of the system and method. of the present
invention, numerous modifications, variations,
alterations and the like will occur to those skilled in
the art. It is, therefore, intended that the foregoing
specification be considered only as illustrative of the
present invention, and that the invention be limited only
by the terms of the appended claims.
