VARIABLE TENSION POST FIXATION
A variable tension post fixation device includes an outer screw including a head configured to receive a driver, a conical tip, a threaded shaft extending between the head and the tip, and an incompletely cannulated core, and an inner screw including a proximal end, a distal end, and at least one suture hole, wherein the inner screw is configured to be insertably coupled with the outer screw.
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This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/104,881 filed on Oct. 13, 2008, and incorporated herein by reference. This application is related to U.S. Non-Provisional patent application Ser. No. ______, filed on even date herewith, having attorney docket number R615.103.102, and incorporated herein by reference.
FIELD OF THE INVENTIONThe present invention relates generally to a medical device that facilitates orthopaedic procedures requiring tensioning and fixation of sutures to bone. With this device, variable tension may be applied independently to one or more different sets of sutures. For example, during anterior cruciate ligament (ACL) reconstruction, the device may be used as primary or secondary fixation of an ACL graft on the tibial side of the reconstruction construct. With the device, variable tension may be applied independently to the sutures, such as those found with single or double bundle ACL reconstruction.
BACKGROUND OF THE INVENTIONAnterior cruciate ligament (ACL) reconstruction is one of the most commonly performed procedures on the human knee. Primary surgical goals during ACL reconstruction include restoring translational and rotational stability of the knee. These goals are often achieved by utilizing a soft tissue graft that is fixated on the femoral and tibial sides of the joint. A common cause of graft failure within the first 6 weeks is loss of fixation strength. This loss of fixation strength is more commonly found on the tibial side rather than the femoral attachment of the ACL graft.
To alleviate the loss of fixation strength, surgeons often use a screw and washer on the tibial side of the joint to create a backup fixation whereby the suture tails of the ACL graft are tied around the screw as a post. A simple limitation with this type of backup fixation, however, is that the sutures tied around the screw can not be tensioned once they are tied. Furthermore, with the advent of double bundle ACL reconstruction, a need for independent tensioning of each ACL bundle has evolved. Unfortunately, the simple screw and washer configuration does not allow for independent tensioning of the four suture tails on the two independent bundle limbs.
The ability to attach sutures around a post and then be able to further tension those sutures to a desired tension after they have been tied would be beneficial, for example, during ACL reconstruction. Also, a desirable device would allow for independent tensioning of two sets of suture tails on a single tibial post, including tensioning of suture tails often found on the tibial side of the joint when performing a double bundle ACL graft.
For these and other reasons, there is a need for the present invention.
A desirable fixation device would provide orthopaedic surgeons performing single or double bundle ACL reconstruction with the ability to tension suture tails after the suture tails are attached to the fixation device. The device would allow the surgeon to tension each strand of the suture tails to a desired tension, and then tension the entire construct one last time in a combined fashion if desired.
TechniquesWith reference to
Although the disclosed fixation device is described for use in performing single or double bundle ACL reconstruction, it is understood and within the scope of the present invention for the disclosed fixation device to be used in other procedures where tensioning of sutures is desired.
Variable Tension PostsIn one embodiment of use, a drill guide is placed distal to the exit point of the most distal tibial tunnel, and a pilot hole is drilled in the bone (see
In one embodiment, the outer screw is fully threaded and headless, and includes a series of concentric channels or bores (t, x, y, z) (
The concentric bores or channels of the outer screw allow for insertion of the outer screw into the pilot hole in the bone, and locking of the inner key within the outer screw. In one embodiment, the outer screw is secured in the pilot hole with a driver by engaging the driver in the channel or bore t (
In one embodiment, the key head of the inner key has 2 holes through which sutures are fed. In one embodiment, suture tails 1 and 2 are fed through the key head from the bottom up and then tied to each other (
Once the desired tension on the sutures has been obtained, the driver is used to rotate the inner key and advance the key tip through the channel or bore x until the key tip reaches the channel or bore y (
In one embodiment, locking pin slots are provided in the key head, and locking pins are inserted into the slots to prevent the inner key from rotating relative to the outer screw when the inner key is in the “locked” position (
In one embodiment, if the ACL bundles need to be further tensioned, the entire construct (inner key and outer screw) can be advanced farther into the pilot hole by inserting the driver into the key head and turning the entire construct clockwise. Because the outer diameters of the outer screw and the inner key are essentially the same, the entire construct can be advanced as a unit even beyond the cortex of the tibial bone posteriorly.
The variable tension post fixation device of
The inner key of the variable tension post fixation device of
In one embodiment, the inner portion of the outer screw of the variable tension post fixation device of
The variable tension post fixation device of
In one embodiment, the outer screw is incompletely cannulated and includes side channels that are cut partially along the sides to receive mating expansion keys or tabs of a cylindrical driver (
In one embodiment, the shaft of the inner screw includes a central hole through which suture tails 3 and 4 are fed and then tied to each other (
In one embodiment, the shaft of the inner screw narrows under the head to accommodate the suture tails 3 and 4 as the inner screw is rotated within the outer screw. In addition, in one embodiment, to avoid entanglement of suture tails 3 and 4 in the locking threads between the inner screw and the outer screw, the sutures are fed through side channels provided in the outer screw before the locking threads are engaged.
The variable tension post fixation device of
In one embodiment, suture tails 1 and 2 are fed through the suture eyelets provided on the outer screw, and the outer screw is thread into the pilot hole as described above (
In one embodiment, prior to tensioning suture tails 3 and 4, a cap that engages the inner screw with its own hex head is placed on the inner screw. As such, the cap and the inner screw are rotated to achieve the desired tension on sutures 3 and 4. Once the desired tension is achieved, the inner screw is press fit into the outer screw and the cap is crimped onto the outer screw. The outer screw, the inner screw, and the cap are now a single unit (
In one embodiment, the outer screw is incompletely cannulated and includes side channels that are cut partially along the sides to receive mating expansion keys or tabs of a cylindrical driver, as described above. In one embodiment, external suture eyelets are provided beneath the head of the outer screw such that before completely sinking the outer screw head flush with the cortex of the tibial bone, suture tails 1 and 2 are fed through the external eyelets and tied to each other (
In one embodiment, the inner screw is free of threads and includes a shaft that fits inside the outer screw (
The embodiments of a variable tension post fixation device described herein provide orthopaedic surgeons with the option of using a single tibial post for fixation and the ability to provide variable tension independently to more than one suture stand.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.
Claims
1. A variable tension post fixation device comprising:
- an outer screw comprising a head configured to receive a driver, a conical tip, a threaded shaft extending between the head and the tip, and an incompletely cannulated core; and
- an inner screw comprising a proximal end, a distal end, and at least one suture hole,
- wherein the inner screw is configured to be insertably coupled with the outer screw.
2. The device of claim 1, wherein the outer screw includes at least two side channels configured to receive at least two mating expansion tabs of the driver.
3. The device of claim 1, wherein the outer screw includes at least one external eyelet provided on the shaft proximal to the head.
4. The device of claim 1, wherein the incompletely cannulated core is at least partially threaded.
5. The device of claim 4, wherein the inner screw includes a partially threaded portion configured to mate with the at least partially threaded core.
6. The device of claim 1, wherein the inner screw is configured to mate with the driver independent of the outer screw.
7. The device of claim 1, wherein an outer diameter of the inner screw is constricted for a length between the proximal end and the at least one suture hole.
8. The device of claim 1, wherein when the inner screw is assembled with the outer screw, the assembly is rotatable in a unified manner.
9. The device of claim 2, wherein the at least two side channels are configured to accommodate sutures extending from an interior to an exterior of the outer screw.
10. A device for variable tension suture fixation, comprising:
- a cylindrical outer screw including a conical tip, a threaded shaft, a belled head, at least one external eyelet, and a partially cannulated threaded core; and
- an elongated inner body including a central lumen, a threaded head, an opposing tip, and a shaft disposed between the head and the tip,
- wherein the inner body is configured to be removably secured within the partially cannulated threaded core, and
- wherein the inner body cooperates with the outer screw to provide for variable tension fixation of at least two sutures.
11. The device of claim 10, wherein the inner body is configured to secure and tension a first set of sutures and the outer screw is configured to secure and tension a second set of sutures.
12. The device of claim 11, wherein the first set of sutures extend from the central lumen of the inner body and exit the outer screw through at least one side channel when fully assembled.
13. The device of claim 10, wherein the belled head includes at least one side channel configured to mate with a driver.
14. The device of claim 10, wherein the threaded head is configured to mate with a driver.
15. The device of claim 10, wherein the inner body is rotatable within the partially cannulated threaded core to a locked position.
16. The device of claim 10, wherein the shaft of the inner body is narrowed for a length between the central lumen and the threaded head.
17. A single fixation device for variably tensioning ACL bundles, comprising:
- means for securing and tensioning a plurality of sutures to allow a first ACL bundle to be variably tensioned independent of a second ACL bundle.
18. The device of claim 17, wherein the means comprises a rotatable outer body, wherein tension of a first pair of the plurality of sutures is adjusted with rotation of the outer body.
19. The device of claim 18, wherein the means further comprises an inner body rotatably coupled within the outer body, wherein a second pair of the plurality of sutures is independently adjusted through rotation of the inner body within the outer body.
20. The device of claim 19, wherein the means further comprises the inner body in a locked position within the outer body whereby the inner body and the outer body are rotated in combination to provide tension to the plurality of sutures.
Type: Application
Filed: Oct 13, 2009
Publication Date: Apr 15, 2010
Applicant: ROCKFORD ORTHOPAEDIC SPORTS MEDICINE SERVICES, LLC (Belvidere, IL)
Inventor: Scott Trenhaile (Belvidere, IL)
Application Number: 12/578,327
International Classification: A61B 17/86 (20060101); A61B 17/04 (20060101);