Not Applicable.
1. The Field of the Invention
The present invention relates generally to ligament and tendon graft attachment devices, and more particularly, but not necessarily entirely, to a ligament fixation system having adjustable tightening qualities.
2. Description of Related Art
This invention relates to tibial fixation for anterior or posterior cruciate ligament reconstruction of the knee. Current practice involves the use of screws, staples, spiked washers, or suture buttons to secure a ligament substituted to the tibia. The ability to secure the ligament substituted within the bone (endosteal) is known in the prior art.
Apparatus and methods for attaching ligaments to bone have been developed and are preexisting in the prior art. Typically, these devices either attach a ligament graft to the exterior of a bone, or within a drill hole bored through the endosteal portion of the bone. The strength of the graft attachment in such systems is usually dependent on the cancellous bone density of the bone.
There are several other ligament fixation devices known in the prior art, such as that disclosed in U.S. Pat. No. 4,870,957 (the “'957 patent”), which is incorporated by reference herein in its entirety. The device disclosed in the '957 patent features an eyelet attached to a stud. A ligament graft is placed into the eyelet by looping the graft and passing the looped graft through a channel in the stud to the eyelet. The stud is then passed into a drill hole bored into the bone. A threaded footing is placed in the drill hole, disposed on threads tapped into the walls defining the drill hole. The stud is seated within a portion of the threaded footing in a type of rotational interference fit, and the threaded footing is then turned on the tapped threads until a desired ligament tension is reached. This system thus requires the drill hole in the bone to be threaded, an additional surgical procedure that introduces the potential of the bone threads stripping or being misaligned. It further requires the stud to be placed into the drill hole from the same direction in which the ligament graft enters, increasing the complexity of the surgery and the number of items that must pass through the joint across which the ligament passes. An additional limiting factor is that the device can only be used with grafts that are formed into loops. The device shown in the '957 patent thus would not be suitable for use with bone-tendon-bone (BTB) implants, including the recent anterior cruciate ligament (ACL) reconstruction technique that involves flipping one end of a patellar tendon autograft (PTA), details of which are described in Barber, A. F., Flipped Patellar Tendon Autograft Anterior Cruciate Ligament Reconstruction, Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol. 16. No. 5, pp 483-490, (July-August, 2000), which is hereby incorporated by reference herein in its entirety.
Implanting a BTB ligament graft has been traditionally accomplished by inserting the graft into a drill hole bored into a bone, and by inserting a screw next to the bone plug of the graft to compress the bone plug against the wall of the drill hole. Examples of this technique are found in Barber (cited above), and in U.S. Pat. No. 5,282,802, which is hereby incorporated by reference herein in its entirety. Since the graft is held in place by frictional engagement between the bone plug and the wall of the drill hole, the strength of the attachment is proportional to the density of the bone. Additionally, the screw must be placed against the cancellous side of the bone plug, rather than the cortical side, to reduce the chances of graft pullout. Such factors limit the positions in which the bone plug may be rotated. Such fixation factors also do not allow for simple adjustment of the graft tension.
Other prior art devices operate either by holding a graft within a bone channel by compressing a pretensioned graft between its own components, such as that disclosed in U.S. Pat. No. 4,708,132 to Silvestrini, which is incorporated by reference in its entirety, or by attaching the graft to connectors located on the exterior surface of the bone, such as that disclosed in U.S. Pat. No. 4,778,468 to Hunt et al., or U.S. Pat. No. 4,772,286 to Goble et al., each of which is incorporated by reference herein in its entirety. By placing a connector on the exterior surface of the bone, such devices leave the connector exposed to soft tissues, which can lead to sensitivity, or potential pain if the area is bumped sufficiently to cause the soft tissue to strike the connector or to cause other complications.
Current ACL fixation techniques may lead to only an 80-90% rate of stabilization regardless of graft choice or fixation device. A great deal of time and energy is currently being directed to increase the success rate of ACL reconstructions. The tibial attachment site is highly suspect due to the inconsistent density of the cancellous bone of the proximal tibia. Devices that rely on interference fixation may be at risk for settling which may explain the laxity that may develop in a small number of patients. It has also been recognized that the process of passing an interference screw over a bone plug may sometimes result in the loss of tension in the graft because the mechanical advantage of the screw passing into the bone may be greater than the manual tension that can be applied pulling the graft taut. It is also believed that in the ideal case, the ACL graft may have a range of acceptable tension at initial placement. Grafts that are placed either too tightly or without sufficient tension will have undesired laxity. This range has not yet been quantified but is vigorously being pursued by many investigators. It is anticipated that a range of quantified tension will be identified and desirable to include on every ACL reconstruction.
The prior art is thus characterized by several disadvantages that are addressed by the present invention. The present invention minimizes, and in some aspects eliminates, the above-mentioned failures, and other problems, by utilizing the methods and structural features described herein.
It is therefore an object of the present invention to provide a ligament graft or tendon graft attachment system that is simple in design and manufacture.
It is another object of the present invention to provide such a ligament graft attachment system that can be used with any graft substitute.
It is an additional object of the present invention to provide such a ligament graft system in which the graft fixation strength is not dependent on the cancellous bone density of the bone.
It is a further object of the present invention to provide such a ligament graft attachment system that enables the tension of the ligament graft to be adjusted.
It is an additional object of the present invention to provide such a system that can be completely recessed into the bone.
It is another object of the present invention, in accordance with one aspect thereof, to provide a ligament graft attachment system that may be inserted and attached through a hole drilled in the bone, without fully inserting a component into the joint.
It is yet another object of the invention, in accordance with one aspect thereof, to provide a ligament graft attachment system that uses a stepwise interference fit to adjust the ligament graft tension.
The above objects and others not specifically recited are realized in a specific illustrative embodiment of an endosteal tibial ligament fixation system with adjustable tensioning. A grasping hook located on a shaft is used to draw a ligament graft into a contoured drill hole formed in a bone. A series of slanted ridges on the shaft can pass in only one direction through a securing push nut residing in the contoured drill hole, resulting in a interference fit that secures the attachment system, while allowing the tension of the ligament graft to be adjusted.
One advantage of the invention device is that it accommodates all currently know graft substitutes, bone patellar tendon bone, Achilles tendon bone, central quad tendon, and hamstring tendons. This device also anticipates the eventual development of an artificial ligament which would have a closed loop at the tibial end. Thus this device would be suitable for every ACL/PCL surgeon.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by the practice of the invention without undue experimentation. The objects and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims.
The above and other objects, features and advantages of the invention will become apparent from a consideration of the subsequent detailed description presented in connection with the accompanying drawings in which:
For the purposes of promoting an understanding of the principles in accordance with the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications of the inventive features illustrated herein, and any additional applications of the principles of the invention as illustrated herein, which would normally occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention claimed.
The publications and other reference materials referred to herein to describe the background of the invention and to provide additional detail regarding its practice are hereby incorporated by reference herein. The references discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as a suggestion or admission that the inventor is not entitled to antedate such disclosure by virtue of prior invention.
It must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.
In describing and claiming the present invention, the following terminology will be used in accordance with the definition set out below.
“Interference fit” as used herein shall refer to the concept of a connection between two members in which a portion of one member abuts some portion of the other member in a manner that contactably blocks the separation of the two members.
Applicant has conceived of a system and methods for attaching a ligament graft to the endosteal portion of a bone where the strength of the attachment is independent of the cancellous bone density, and the tension on the ligament may be adjusted. Further, this system may be used with any available ligament or tendon graft.
The present invention adds to the ability of a surgeon to use endosteal technology in such a fashion that tension to the ligament construct can be added in an easily quantifiable and adjustable manner. It is well known that the bone density of the tibial varies widely dependent upon age, weight, and gender of the subject. The mechanism by which fixation is achieved by this inventive device is such that graft fixation strength is not dependent upon the density of the tibial cancellous bone.
Referring now to
Returning to
As shown in
The attachment member 10 and push nut 20 may be fashioned of any suitable bio-compatible material including metal, such as titanium, stainless steel, cobalt-chromium-molybdenum alloy, titanium-aluminum vanadium alloy, or other alloys thereof, or of a plastic such as an ultra high molecular weight polyethylene, or of a bio-absorbable material such as poly L-lactic acid.
Turning now to
As shown in
A ligament graft 42 is attached at one end to the appropriate anatomical structure, such as the femur. Any suitable ligament graft may be used, including a bone patellar tendon bone implant (BTB), an Achilles tendon bone implant, a central quad tendon implant, a hamstring tendon implant, an artificial ligament material, or any other suitable ligament graft known now or in the future to those skilled in the art. The ligament graft depicted in
Referring now to
In
When the ligament graft 42 has reached the desired tension, the portion of the shaft 14 protruding from the larger diameter portion 41 of drill hole 40 is preferably cut off, thereby causing the entire system 25 to reside within the drill hole 40 of the bone T. Patella P is also shown.
Referring now to
A ligament graft 42 is inserted into the drill hole 70. This graft may be a BTB graft, as depicted in
In the embodiment of
Referring now to
The attachment member 124 is secured within the contoured drill hole 126 by the attachment of a nut 130 to the threaded shaft 128 of the attachment member. A washer 132 is disposed between the nut 130 and an annular retaining wall 134 of the contoured drill hole. The washer prevents the rotation of the nut 130 from damaging the annular retaining wall 134.
Tension on the ligament graft 120 may be measured and adjusted by turning the nut 130. While the nut 130 may be any appropriate threaded attachment device, it is preferred to use a suitable hex nut as known in the art. It is preferred that the washer 132 be a plate washer, but any suitable washer may be used. It is further preferred that the plate washer 132 be fashioned of sheet metal. The nut 130 and washer 132 are another example of a securing means for securing the attachment member 124.
When the attachment member is disposed in contoured drill hole 155, grasping ligament graft 160. The attachment member is fixedly attached to a retention disc 158, such as with an optional locking nut 156 or in any other suitable manner. The retention disc 158 may be rotated to twist the flexible strand 152 as shown, and thereby adjust the tension of the ligament graft 160. When the desired tension is reached, the disc may be secured by insertion of a fixation screw 159 into the bone T as shown, to prevent untwisting of the strand 152. The fixation screw 159 may be placed through the body of the retention disc 158, or through a fixation hole 161 formed in the retention disc, such as disk 158A of
It will be appreciated that additional embodiments of the continuous loop flexible strand embodiment of
The free end 180a of cable 180 is used to capture a ligament graft 190 and draw the graft 190 into a contoured drill hole 188. The cable 180 passes back through a second hole in the retention disc 184 and a second passage in the cable collector 182. The cable 180 may be inserted back through the disc 184 and collector 182 prior to, or after, capture of the ligament graft 190.
Tension of the ligament graft 190 may be measured in any suitable manner known to those having ordinary skill in the art, (such as by coupling the device with a tension measuring apparatus to measure the tension within the graft 190 precisely). The tension may be adjusted by retension of the free end 180a to thereby shorten the cable 180. The retention disc 184 secures the attachment member cable 180 in place by abutting against the annular retaining wall 194 of the contoured drill hole 188. When a desired tension is reached, the cable 180 is secured. In the embodiment of
Reference will now to made to
It will be appreciated that the additional embodiment of the disclosure illustrated in
Another embodiment of the matrix 214 may include a calcium-phosphate material. For example, a monocalcium phosphate, mono-hydrate, α-tricalcium phosphate, and calcium carbonate may be mixed dry then suspended in a sodium phosphate solution. This process may result in the formation of an injectable paste that may begin to harden in minutes to form a carbonated apatite (dahllite) through a non-exothermic reaction. The calcium-phosphate material may have beneficial characteristics. For example, the calcium-phosphate material may be osteoconductive, have substantial compressive strength, and may be resorbed or converted to host bone over time.
It will be understood that the matrix 214 may be formed of various other biologically compatible materials known in the art. The composition of the matrix 214 may also be configured to contain osteoinductive substances, or any variety of substances known in the art to promote healing. Some embodiments of the matrix 214 may also be configured to resorb or be converted to host bone over time, while other embodiments of the matrix 214 may not be resorbable. Moreover, it will be understood that graft in-growth enhancing factors may be delivered using this technique as well.
A strand 216 may be used as a grasping means to grasp a free end of the ligament graft 210. It will be understood that various other types of grasping means known in the art may be used as part of an attachment member within the scope of the present disclosure. The strand 216 may be looped around the ligament graft 210 at its bend and the strand 216 may exit the tibia T. The strand 216 may be attached to a tensiometer (not shown) and a known tension may be applied to the strand 216. The drill hole 212 may have a flared opening 218 for receiving the matrix 214. The matrix 214 may be injected into the drill hole 212 using any injection device known in the art to allow the matrix 214 to be placed in a manner that may accommodate the strand 216 attached to the tensiometer. The matrix 214 may be installed in a distal to proximal direction and prior to setting, the knee may be brought into extension. The strand 216 attaching the graft 210 may remain in place and may be shortened after the matrix 214 has solidified.
To facilitate holding the matrix 214 in the drill hole 212 when the matrix 214 is in a liquid state, a retaining member 220 may be used. The retaining member 220 may have openings 222 for receiving the strand 216 therethrough, and may be positioned against the flared opening 218 of the drill hole 212. It will be understood that the retaining member 220 may remain in place after the matrix 214 has solidified, or the retaining member 220 may be removed. Moreover, the retaining member 220 may be have various different sizes and configurations within the scope of the present disclosure.
Fixation of the graft 210 may occur either by the strand 216 passing through the mass of hardened matrix 214, or via the mass of the hardened matrix 214 itself passing around the geometry of the graft 210.
Accordingly, the present disclosure provides a means of strong reliable tibial fixation that may allow for a known tension to be applied. Moreover, the present system may eliminate metal as a fixation material, it may eliminate post surgical tunnel widening, provide for a mechanism to instill graft in-growth accelerators or osteoinductive compounds, and may utilize a matrix that may ultimately be resorbed into host bone thus restoring the tibia to normal. Moreover, the present embodiment may take advantage of utilizing a graft with an attached bone plug.
In accordance with the features and combinations described above, an exemplary method of attaching a ligament or tendon implant to the endosteal portion of a bone may include the steps of:
The method may further include step (g) waiting for the matrix to solidify at least partially, before closing or suturing surgical openings in the patient.
In accordance with the features and combinations described above, another method of attaching a ligament or tendon implant to the endosteal portion of a bone includes the steps of:
It is further preferred to drill a contoured hole having a larger diameter portion and a narrower diameter portion as described, such that the securing mechanisms as disclosed herein can be used in the above method. Any known ligament graft material may be used.
In accordance with the features and combinations described above, another preferred method of attaching a ligament or tendon implant to the endosteal portion of a bone includes the steps of:
It is preferred to drill a contoured hole with a larger diameter portion, such that the securing mechanisms as disclosed herein can be used in the method. It is further preferred that the securing means be disposed to attach to the shaft of the attachment member. It is also preferred that the first direction is opposite the direction in which the attachment member is inserted. Any known ligament graft material may be used.
Another preferred method of attaching a ligament or tendon implant to the endosteal portion of a bone includes the steps of:
(f) adjusting the tension of the implant to a predetermined tension by activating the tensioning means; and
The flexible grasping means may comprise a flexible continuous loop attached to the tensioning means, or a flexible strand that may be attached to the tensioning means, or any suitable means for accomplishing the function described.
It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present invention and the appended claims are intended to cover such modifications and arrangements. Thus, while the present invention has been shown in the drawings and fully described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred embodiment(s) of the invention, it will be apparent to those of ordinary skill in the art that numerous modifications, including, but not limited to, variations in size, materials, shape, form, function and manner of operation, assembly and use may be made without departing from the principles and concepts set forth herein.
This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 10/705,393, filed Nov. 10, 2003, entitled “ENDOSTEAL TIBIAL LIGAMENT FIXATION WITH ADJUSTABLE TENSIONING,” which is a continuation of U.S. patent application Ser. No. 10/430,769, filed May 5, 2003, entitled “ENDOSTEAL TIBIAL LIGAMENT FIXATION WITH ADJUSTABLE TENSIONING,” which is a continuation of patent application Ser. No. 09/846,552, filed Apr. 30, 2001, entitled “ENDOSTEAL TIBIAL LIGAMENT FIXATION WITH ADJUSTABLE TENSIONING,” now U.S. Pat. No. 6,558,389, which is a continuation of U.S. patent application Ser. No. 09/734,315, filed Nov. 30, 2000, entitled “ENDOSTEAL TIBIAL LIGAMENT FIXATION WITH METHOD OF ADJUSTING TENSIONING,” which claimed the benefit of U.S. Provisional Application No. 60/168,066, filed Nov. 30, 1999, entitled “ENDOSTEAL TIBIAL LIGAMENT FIXATION WITH METHOD OF ADJUSTABLE TENSIONING” which applications are hereby incorporated by reference herein in their entireties, including but not limited to those portions that specifically appear hereinafter, the incorporation by reference being made with the following exception: In the event that any portion of the above-referenced applications is inconsistent with this application, this application supercedes said above-referenced applications.
Number | Date | Country | |
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60168066 | Nov 1999 | US |
Number | Date | Country | |
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Parent | 10430769 | May 2003 | US |
Child | 10705393 | Nov 2003 | US |
Parent | 09846552 | Apr 2001 | US |
Child | 10430769 | May 2003 | US |
Parent | 09734315 | Nov 2000 | US |
Child | 09846552 | Apr 2001 | US |
Number | Date | Country | |
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Parent | 10705393 | Nov 2003 | US |
Child | 10873765 | Jun 2004 | US |