U.S. patent application number 12/490193 was filed with the patent office on 2009-10-22 for retrograde fixation technique with insert-molded interference screw.
Invention is credited to Craig D. Morgan, Philip S. O'Quinn, Reinhold Schmieding, Jeffrey Wyman.
Application Number | 20090265004 12/490193 |
Document ID | / |
Family ID | 46281949 |
Filed Date | 2009-10-22 |
United States Patent
Application |
20090265004 |
Kind Code |
A1 |
Morgan; Craig D. ; et
al. |
October 22, 2009 |
RETROGRADE FIXATION TECHNIQUE WITH INSERT-MOLDED INTERFERENCE
SCREW
Abstract
Endosteal fixation of a ligament graft with a bioabsorbable
interference screw installed in a retrograde manner in ACL
reconstruction. The bioabsorbable interference screw is
insert-molded with a length of suture extending from the distal tip
of the screw for pulling the interference screw into the joint and
into position for retrograde insertion at the top of the tibial
tunnel. The interference screw has a cannulation extending
partially through the screw from the leading tip. The cannulation
is shaped to receive a correspondingly shaped driver. The driver is
inserted into the tibial tunnel to engage the screw. By turning the
driver, the interference screw is turned into the tibial tunnel in
a retrograde manner. Accordingly, interference fixation of the
graft near the tibial plateau is provided, thereby eliminating
graft abrasion at the tibial plateau tunnel opening.
Inventors: |
Morgan; Craig D.;
(Greenville, DE) ; Wyman; Jeffrey; (Naples,
FL) ; Schmieding; Reinhold; (Naples, FL) ;
O'Quinn; Philip S.; (Naples, FL) |
Correspondence
Address: |
DICKSTEIN SHAPIRO LLP
1825 EYE STREET NW
Washington
DC
20006-5403
US
|
Family ID: |
46281949 |
Appl. No.: |
12/490193 |
Filed: |
June 23, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10358192 |
Feb 5, 2003 |
7556638 |
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12490193 |
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10256076 |
Sep 27, 2002 |
7063717 |
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10358192 |
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|
09864258 |
May 25, 2001 |
6461373 |
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10256076 |
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60207235 |
May 26, 2000 |
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Current U.S.
Class: |
623/13.14 |
Current CPC
Class: |
A61F 2/0805 20130101;
A61B 17/8875 20130101; A61F 2/0811 20130101 |
Class at
Publication: |
623/13.14 |
International
Class: |
A61F 2/08 20060101
A61F002/08 |
Claims
1-10. (canceled)
11. A method of anterior cruciate ligament reconstruction, the
method comprising the steps of: forming a femoral socket in a
femur; feeding a length of suture extending from a leading tip of
an interference screw into the joint cavity and through a tunnel
extending from the socket to the exterior of the femur, the suture
being insert-molded into the interference screw; placing a ligament
graft in the femoral socket; drawing on the free end of the suture
to pull the interference screw into the joint cavity into axial
alignment with the socket; using a driver to engage a cannulation
extending into the interference screw; and screwing the
interference screw into the socket by turning the driver.
12. The method of claim 11, wherein the cannulation extends into a
back end of the interference screw, and the interference screw is
screwed forwardly into the socket.
13. The method of claim 11, wherein the cannulation extends into
the leading tip of the interference screw, and the interference
screw is screwed in retrograde fashion into the socket.
Description
[0001] This is a continuation-in-part of U.S. application Ser. No.
10/256,076, filed Sep. 27, 2002, which is a continuation-in-part of
U.S. application Ser. No. 09/864,258, filed May 25, 2001, now U.S.
Pat. No. 6,461,373, and claims the benefit of U.S. Provisional
Application Ser. No. 60/207,235, filed May 26, 2000.
FIELD OF THE INVENTION
[0002] The present invention relates to interference screw fixation
of replacement ligament grafts, and more particularly to methods
and apparatus for retrograde placement and installation of an
interference screw for graft fixation in a bone tunnel.
BACKGROUND OF THE INVENTION
[0003] Methods of anterior cruciate ligament (ACL) reconstruction
using interference screw fixation are described in U.S. Pat. Nos.
5,211,647 and 5,320,626, the entire disclosures of which are
incorporated herein by reference. In general, these methods of
tenodesis involve drilling a tunnel through the tibia, drilling a
closed tunnel (socket) into the femur, inserting a substitute ACL
graft into the tunnels, and securing the grafts to the walls of the
tibial and femoral tunnels using interference screws or the like.
Accurate positioning of the tibial and femoral tunnels requires a
drill guide, such as those disclosed in U.S. Pat. Nos. 5,269,786
and 5,350,383, which also are incorporated herein by reference.
[0004] One drawback of the described tenodesis methods is that the
ligament graft is secured only at the bottom of the tibial tunnel.
The graft is not secured at the top end of the tibial tunnel.
Consequently, the graft is free to move from side to side,
resulting in a "windshield wiper" effect, during which the graft
abrades against the upper rim of the tibial tunnel, shortening the
life of the ACL repair.
[0005] U.S. Pat. No. 5,603,716 to Morgan et al. discloses a
technique for ACL reconstruction that avoids the above-noted
problem of graft abrasion. The method disclosed by Morgan et al.
requires forming two closed-ended sockets, one in the tibia and the
other in the femur. However, forming a femoral socket is difficult
without a tibial tunnel for insertion of a femoral guide and
drill.
[0006] Accordingly, the need exists for a method of ACL
reconstruction that provides anatomical graft fixation at the
tibial plateau, and without the need for forming two separate bone
sockets.
SUMMARY OF THE INVENTION
[0007] The present invention overcomes the disadvantages of the
prior art, such as those noted above, by providing methods and
apparatus for endosteal fixation of a ligament graft using an
interference screw that is installed in a retrograde manner. In a
preferred embodiment, anterior cruciate ligament (ACL)
reconstruction is performed using an interference screw installed
in a retrograde manner through the tibial plateau to secure an ACL
graft at the top of the tibial tunnel.
[0008] The interference screw is insert-molded with a length of
suture. The suture extends beyond the leading tip of the screw a
sufficient length to allow the suture to be passed through the
tibial tunnel and to be grasped for pulling the screw into the
tibial tunnel through the top tibial plateau opening. The screw and
suture preferably are bioabsorbable.
[0009] A driver for the screw fits into a cannulation in the
leading end of the screw. Preferably, the driver is cannulated to
accept the length of suture extending from the bottom opening of
the tibial tunnel, and has means for grasping the suture to assist
the surgeon in pulling the interference screw into the top opening
of the tibial tunnel. The screw is blind headed (not fully
cannulated) to eliminate synovial fluid leak through the screw into
the tibial tunnel.
[0010] According to a preferred method of the present invention,
the suture extending from the interference screw is fed through the
joint cavity into the top tibial plateau opening of the tunnel, and
down through the tibial tunnel to exit at the anterior surface of
the tibia. The free end of suture exiting the anterior surface of
the tibial tunnel preferably is inserted through the cannulation of
the cannulated driver and secured around a post on the driver.
[0011] After the ligament graft has been placed in the tibial
tunnel, the suture is drawn using the driver at the anterior
opening of the tibial tunnel to pull the interference screw into
the joint cavity in a retrograde fashion. The knee joint is
positioned to allow the end of the screw to be manipulated into the
top opening of the tibial tunnel, with the screw being pivoted
within the joint cavity to align axially with the tunnel and the
driver.
[0012] With the screw being drawn into a position of alignment with
the tunnel, the driver is advanced into the tibial tunnel. Pulling
on the suture retains the screw in position for engagement with the
driver by applying tension to the suture in the direction opposing
driver insertion.
[0013] Once the driver has engaged the screw, turning the driver
causes the screw to advance, or "back in" to the tunnel in
retrograde fashion. Using a right-threaded screw, a surgeon will
turn the screw counter-clockwise. In an alternative embodiment, the
screw has reverse threads, so that turning the driver clockwise
advances the screw into the tunnel. The screw is turned into the
tunnel until the back end of the screw is substantially flush with
the tibial plateau, and has been installed to a depth sufficient to
provide interference fixation of the graft at the top of the
tunnel. The driver is disengaged from the screw, and excess suture
is removed.
[0014] The insert-molded interference screw of the present
invention can also be inserted forwardly into the femur to fixate a
ligament graft in the femoral socket by passing the suture
extending from the leading tip of the screw through a narrow tunnel
drilled through the femur in alignment with the femoral socket, and
drawing on the suture to pull the screw into the femoral
socket.
[0015] Other features and advantages of the present invention will
become apparent from the following description of the invention
which refers to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view of an interference screw with
insert-molded suture according to the present invention.
[0017] FIG. 2 is a cross-sectional elevation of the screw and
inserted-molded suture of FIG. 1.
[0018] FIG. 3 is a proximal end view of the screw of FIGS. 1 and
2.
[0019] FIG. 4 is an elevation of a driver for the screw of FIGS.
1-3 according to the present invention.
[0020] FIG. 5 is a cross-sectional plan view of the driver of FIG.
4.
[0021] FIG. 6 schematically illustrates fixation of an ACL graft
using the retrograde biointerference screw of the present
invention, and in accordance with one embodiment of the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] Referring initially to FIGS. 1-3, a bioabsorbable
interference screw 2 for tenodesis of an anterior cruciate ligament
graft is shown. Body 4 of the screw 2 features a continuous thread
6 provided substantially along the length of the body from a blunt
front end 8 to a rounded back end 10. The thread preferably has
flattened crests 12 and flattened troughs 14 to obviate ligament
graft damage by the screw threads and enhance graft fixation. A
length of suture 15 is insert-molded into interference screw 2 in a
manner similar to that described in U.S. Pat. No. 5,964,783 and
U.S. Patent Application Publ. No. 2003/0004545 A1, the disclosures
of which are herein incorporated by reference. The suture may be a
conventional surgical suture or an ultrastrong surgical suture,
e.g., Fiber Wire suture, sold by Arthrex, Inc. of Naples, Fla., the
assignee of the present application. Fiber Wire suture is formed of
ultrahigh molecular weight polyethylene and is described in U.S.
Ser. No. 09/950,598, the disclosure of which is herein incorporated
by reference.
[0023] The cannulated body 4 of bioabsorbable interference screw 2
tapers toward the front end 8 to terminate in a blunt tip 16. The
taper eases entry of the screw into the tibial tunnel according to
the preferred method of ligament graft fixation described further
below. The blunt tip 16 of the screw prevents damage of the
ligament graft during insertion of the screw. The rounded back end
10 of the screw minimizes abrasion and wear of the installed
ligament graft. Cannula 18, 19 formed through screw body 4 has a
hexagonal shape for engaging a correspondingly shaped driver as
described below. Preferably, distal portion 18 of the screw cannula
is straight, and proximal portion 19 of the screw cannula is
tapered. To reduce loss of synovial fluid leak through the screw
into the tunnel, the cannula does not extend completely to the back
end screw, but rather terminates internally as shown. The hexagonal
shape of cannula 18, 19 is shown clearly in FIG. 3. The preferred
screw is 20 mm long, and is provided in diameters of 8 mm, 9 mm,
and 10 mm.
[0024] Referring to FIGS. 4 and 5, a driver 20 for installing the
interference screw of the present invention is shown. Driver 20
includes a cannulated shaft 22 attached to a cannulated handle 24.
A drive tip 26 formed at the distal end of shaft 22 has a
straight/tapered, hexagonal shape conforming to straight/tapered
cannula 18, 19 of screw 2. At the proximal end of the handle, a
post 28 is provided for securing suture.
[0025] A method of ACL tenodesis according to a preferred
embodiment of the present invention includes forming a tunnel 30 in
a tibia 32, as shown in FIG. 6. The tunnel is formed with a
diameter appropriate for interference fixation based on the size of
the selected screw 2. Tunnel 30 ascends at an angle posteriorly
from a bottom opening 34 at an anterior tibial surface 36 toward an
upper opening 38 at the tibial plateau. The lower end of an ACL
graft 40 is inserted into the tunnel through the tibial
plateau.
[0026] Screw 2 is inserted into the joint and through the tunnel 30
so that the free end of the insert-molded suture 15 exits the
bottom opening 34. Suture passing instruments known in the art can
be utilized.
[0027] The free end of the suture is used to draw screw 2 toward
the tibial opening 38, either by hand or using driver 20 by
threading the suture through the driver 20 and securing the suture
onto post 28, for example. With the knee joint distended, the screw
2 is manipulated into the tibial plateau opening 38 and pivoted
into axial alignment with the tunnel 30. Driver 20 is advanced into
the tunnel 30 to achieve engagement with screw 2. Once the driver
and screw are engaged, rotation of the screw with the driver
advances the screw into the tunnel 30 in a retrograde manner. Screw
insertion is continued until the back end 10 of screw 2 is
substantially flush with the tibial plateau and the graft 40 is
secured sufficiently within the tunnel. The driver 20 and any
excess suture 15 is removed from the tunnel to complete this
portion of the procedure.
[0028] The insert-molded interference screw of the present
invention can also be inserted into the femur to fixate a ligament
graft in the femoral socket by passing the suture extending from
the leading tip of the screw through a narrow tunnel drilled
through the femur in alignment with the femoral socket, and drawing
on the suture to pull the screw into the femoral socket. The screw
can then be turned into the socket forwardly with a screwdriver
inserted through the tibial tunnel (the screw in this case having a
back end cannulation) or in retrograde fashion with a screwdriver
inserted through the narrow femoral tunnel (the screw in this case
having a leading end cannulation).
[0029] Although the present invention has been described in
relation to particular embodiments thereof, many other variations
and modifications and other uses will become apparent to those
skilled in the art. It is preferred, therefore, that the present
invention be limited not by the specific disclosure herein, but
only by the appended claims.
* * * * *