APPARATUS FOR LOADING TENDONS INTO THE KNEE
A surgical kit for loading ligament grafts into a joint. A longitudinal socket formed in a bone is intersected by a transverse pin. The kit includes a flexible strand that is drawn with a pin through the bone. The strand is positioned so that a looped portion of the strand protrudes out of the entrance to the longitudinal socket. The ends of the strand remaining accessible on either side of the bone. The ligament graft is captured within the strand loop protruding from the entrance to the socket. The strand is retracted into the socket, drawing the graft into the socket. The kit includes an implant for transversely fixing the graft in the socket.
This application is a continuation of application Ser. No. 11/929,637, filed Oct. 30, 2007, now U.S. Pat. No. 7,500,990, which is a continuation of application Ser. No. 11/293,149, filed Dec. 5, 2005, now U.S. Pat. No. 7,306,626, which is a continuation of U.S. application Ser. No. 10/824,603, filed Apr. 15, 2004, now U.S. Pat. No. 6,974,477, which is a continuation of U.S. application Ser. No. 10/355,287, filed Jan. 31, 2003, now U.S. Pat. No. 6,733,529, which is a division of U.S. application Ser. No. 10/121,610, filed Apr. 15, 2002, now U.S. Pat. No. 6,537,319, which is a continuation of U.S. application Ser. No. 09/663,798, filed Sep. 18, 2000, now U.S. Pat. No. 6,371,124, which is a continuation of U.S. application Ser. No. 09/346,709, filed Jul. 2, 1999, now U.S. Pat. No. 6,132,433, which is a continuation of U.S. Application Ser. No. 09/015,618, filed Jan. 29, 1998, now U.S. Pat. No. 5,918,604, which claims the benefit of U.S. Provisional Application Ser. No. 60/037,610, filed Feb. 12, 1997.BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to reconstruction of the anterior cruciate ligament (ACL), and, more specifically, to surgical graft fixation using semitendinosus and gracilis tendon autografts.
2. Description of the Related Art
When a ligament or tendon becomes detached from associated bone, surgery usually is required to re-secure the ligament or tendon. Often, a substitute ligament, or graft, is attached to the bone to facilitate re-growth and permanent attachment. Various methods of ligament graft attachment are known, including staples, suture over buttons, and interference screw fixation.
Various problems exist with the known fixation methods. Staples and suture buttons are disadvantageous because they often do not provide fixation sufficient to withstand the normal tensile loads. With suture button fixation, for example, a strand of suture couples the button and the substitute ligament. This strand becomes the “weakest link in the chain,” and if the strand breaks, the ligament detaches.
A stronger graft attachment can be obtained by interference screw fixation, whereby an interference screw is used to wedge a graft bone block to the wall of a graft tunnel. See, e.g., U.S. Pat. Nos. 5,211,647, and 5,603,716, incorporated herein by reference.
Although interference screw attachment is more secure than using staples or suture buttons, it is sometimes neither possible nor desirable to provide such fixation, particularly in the femoral tunnel. In revision situations, for example, where a previous reconstruction has been performed, placing a second femoral tunnel placed close to the previous tunnel may not be indicated.
In other cases, a semitendinosus graft must be used because the previous reconstruction used the mid third patellar tendon. Although a bone-semitendinosus graft-bone construct may be prepared using a workstation as disclosed in U.S. Pat. No. 5,397,357, such a procedure is time consuming, and may be undesirable for other reasons.
A fixation technique which provides strong attachment of a semitendinosus graft in the femoral tunnel, using a transverse implant, is disclosed in U.S. Pat. No. 5,601,562, of common assignment with the present application, and incorporated herein by reference. The transverse implant is inserted through a loop in a tendon graft. A threaded portion of the implant screws into the bone as the implant is advanced with rotation into the repair site. The technique is disadvantageous, however, because the graft can become wrapped around the implant as it is rotated. An improved bone implant is the subject of U.S. Pat. No. 5,895,425.
In addition, the prior art technique noted above requires a forked insertion tool, and a large femoral tunnel is needed to accommodate the forked insertion tool. As a result, the large femoral tunnel undesirably allows the graft to slide laterally, or “wipe” back and forth, along the fixation implant. Moreover, the diameter of the implant necessarily is limited by the size of the opening in the forked insertion tool.
As a further disadvantage, the technique also requires the extra steps of forming and wedging a bone plug into the femoral tunnel after insertion of the ligament. Moreover, the technique does not accommodate a closed-loop graft construct, since the graft must have a free end in order to be inserted with the forked insertion tool. Further, the technique may not be indicated in revision procedures.
Various endoscopic techniques and instruments relating to graft fixation are known in the prior art and can be used in the practice of the present invention. U.S. Pat. No. 5,320,636 to Schmieding discusses an endoscopic drill guide for graft tunnel location. U.S. Patent No. Des. 378,780 illustrates a cannulated headed reamer as can be used in femoral socket formation. U.S. Pat. Nos. 5,269,786 and 5,350,383 disclose drill guides for location of bone tunnels.
The need exists for fixation techniques that utilize narrower femoral/tibial tunnels, to prevent wiping, and that do not require the insertion of bone plugs. Also, the need exists for graft ligament loading techniques that can accommodate closed-looped grafts, that do not require specialized insertion tools to load the graft into the knee, and that can be indicated in certain revision procedures.SUMMARY OF THE INVENTION
The present invention overcomes the problems of the prior art and fulfills needs such as those noted above by providing a surgical method for loading tendon grafts into a joint and fixating the grafts using a transverse, intraosseous implant. The inventive technique advantageously uses narrow tibial and femoral tunnels, and eliminates the use of sutures, tapes, or extra-osseous metal fixation devices. The procedure also is indicated for revisions that would otherwise be jeopardized by secondary femoral tunnel creation. In addition, the technique can be implemented using a transverse implant that is advanced by impaction into the bone.
As applied in the knee, the method includes the use of standard techniques to drill a longitudinal tunnel in the tibia. Subsequently, a femoral socket is formed, preferably in the lateral femoral condyle. According to the present invention, forming the socket is preferred to forming a tunnel through the lateral femoral cortex. Advantageously, the diameters of the tibial tunnel and femoral socket are made just large enough to accommodate the graft in a snug fit.
A tunnel hook, mounted on a cross-pin drill guide, is inserted through the tibial tunnel and into the femoral socket. A drill pin directed by the drill guide is drilled through the femur to intersect the femoral socket. The drill pin passes through the capture slot of the tunnel hook.
A hole then is formed in the femur, preferably using a cannulated drill placed over the guide pin, to accommodate a threaded section of the transtibial implant. A channel is formed in the lateral femoral cortex to accommodate the remainder of the implant, preferably using a dilator placed over the guide pin.
Next, a flexible strand, preferably a wire formed of nitinol, is attached to the guide pin and pulled through the femur. Equal lengths of the strand protrude from the medial and lateral sides of the femoral shaft, and are secured to prevent accidental pull-out. The tunnel hook is withdrawn, the strand being captured in the slot of the hook.
The hook is retracted completely, through the femoral socket and out of the tibial tunnel, such that a loop of the flexible strand protrudes from the entrance to the tunnel. Free ends of the strand remain exposed on either side of the femoral shaft.
The graft is passed through the diverted loop of the flexible strand. The loop is retracted into the femoral socket by pulling evenly on the medial and lateral ends of the strand. As a result, the graft is drawn into the socket.
The cannulated implant is placed over the wire and driven into the femur. The implant preferably is formed with back-biting threads. Accordingly, the implant easily can be impact driven into the repair site, and yet can be removed if necessary by rotation. The cannulated implant passes over the strand and under the tendon, thus securing the graft in the femoral socket.
Tibial fixation of the graft can be performed by various known methods, including interference screw fixation, which provides the most secure post-operative result; distal fixation with a cancellous screw using a post and washer technique; and a belt buckle staple technique utilizing a pair of ligament staples.
An alternative method of tendon loading is also provided for a closed-loop graft reconstruction. According to the alternative method, a flexible line is joined to one end of the strand. A strand/line loop is formed so as to protrude from the entrance to the tibial tunnel and present the junction between the strand and the line. The strand and the line are dejoined, opening the strand/line loop to accept the graft. The strand and line are rejoined so as to capture the graft, and the procedure continues substantially as set forth above.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings. For example, although the description herein relates to ACL grafts and forming femoral tunnels in the knee, it will become apparent that expanded indications for the inventive method include other joints and replacement of other ligament or tendon structures using various types of graft constructs.
Referring initially to
Various features of tunnel hook 2 are provided for ease of use in the inventive procedure of the present invention. The purpose of the following features will become more clear in light of the method described below. Angled opening 8 allows escape of a graft-passing wire from capture slot 6. Channels 10 on either side of hook 4 accommodate portions of the graft-passing wire as it forms a loop through a femoral tunnel. The proximal end of tunnel hook 2 features a mounting flange 11 for engagement with a drill guide.
The method of the present invention is described with reference to
Once the tibial tunnel is formed, a cannulated headed reamer is used to form a closed-ended socket 60 in the femur 62. The socket is formed to a minimum depth of about 40 mm to accommodate the insertion depth of tunnel hook 2. The knee should be placed in 900 of flexion when forming the tibial tunnel and femoral socket.
The tunnel and socket can be modified in various ways using tunnel taps. For example, crenulations formed in the tibial tunnel provide additional friction and helps eliminate unwanted graft rotation during interference screw insertion. A spiral groove formed in the tunnel wall provides additional interference friction of the graft collagen against the compressed cancellous bone in the tunnel. A rasp may be used to create an oval-shaped tunnel and femoral socket to accommodate insertion of four tendon strands.
After the tibial tunnel and femoral socket are complete, tunnel hook 2, fitted onto a C-ring cross-pin drill guide 64, is inserted through tibial tunnel 56 and into femoral socket 60. Tunnel hook 2 will capture within slot 6 the graft-passing wire 12 used in loading the graft tendons into the femoral socket, as described below with respect to
Referring again to
With the sleeve in position against the cortical bone, drill pin 12, 2 mm. in diameter, is chucked into a power drill 68, and advanced with rotation through the femur until it exits the skin on the medial side 70. To ensure that the drill pin passes within the capture slot 6 of tunnel hook 2, torque on the drill guide and changes in knee flexion are avoided during drilling.
The implant is advanced along the wire in the direction of arrow F. The implant passes under the loop formed in tendons 76, toward the medial side of the femur, to provide cross-pin support of tendons 76. If removal of the implant should become necessary, reverse cutting threads 44 facilitate removal by unscrewing the implant with a 3.5 mm hex head screwdriver.
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. Therefore, the present invention is to be limited not by the specific disclosure herein, but only by the appended claims.
1. A surgical kit for performing ACL reconstructive surgery on a knee, comprising:
- (a) a flexible strand for supporting a graft in an opening in the knee;
- (b) a drill pin;
- (c) a drill guide for receiving and positioning the drill pin with respect to a knee; and
- (d) a cannulated implant for transverse fixation of the graft in the knee.
2. The surgical kit of claim 1, wherein the flexible strand comprises a nitinol wire.
3. The surgical kit of claim 2, wherein the cannulation of the implant is sized to accept the nitinol wire, such that the implant can be advanced into the knee over the nitinol wire.
4. The surgical kit of claim 1, wherein the implant has a tapered distal end.
5. The surgical kit of claim 1, wherein the implant has a threaded back end.
6. The surgical kit of claim 1, wherein the implant has a socket in the proximal end for receiving a driver to rotate the implant.
7. The surgical kit of claim 1, wherein the drill guide is in the form of a C-ring.
8. The surgical kit of claim 1, further comprising a cannulated headed reamer for drilling a tunnel in bone.
9. The surgical kit of claim 1, further comprising a tunnel dilator.
10. The surgical kit of claim 1, wherein the drill pin has a distal end with a point and a proximal end with a hook for receiving the flexible strand.
11. The surgical kit of claim 1, further comprising a tunnel hook for grasping the flexible strand and pulling into down through a tunnel in bone.
12. The surgical kit of claim 1, wherein the implant is configured to be secured in bone by impaction.
Filed: Mar 5, 2009
Publication Date: Jul 2, 2009
Inventor: Jeffery M. Whelan (Sugarland, TX)
Application Number: 12/398,594