The present invention relates generally to surgical devices and procedures used in the field of arthroscopic surgery, particularly to devices for preparation of grafts for reconstruction of the anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) of the knee, and more particularly to devices for securing connective tissues in any ligament replacement grafts.
When performing anterior cruciate ligament reconstruction a bone tunnel is formed in the tibia and in the femur so that a ligament replacement graft may be inserted and secured therein. A ligament replacement graft may be a semitendonous tendon, a patellar tendon, or other ligament replacement attached to and between a pair of bone blocks which have been sized for close fitting arrangement within one of the femoral and tibial tunnels. The ligament replacement may be from an allogenic (cadaveric) or autogenous (patient) source. One common approach to ACL reconstruction is the use of patellar tendon to form a bone-tendon-bone graft (BTB).
Each type of replacement ligament used in ligament reconstruction techniques has its own set of benefits and complications. Amongst autogenous grafts, complications relate specifically to two areas: graft site morbidity and fixation modality. Complications associated with graft harvest are numerous. The incision used to harvest the patellar tendon is longer than the incision through which arthroscopic surgery is performed. This added length and additional opening into the body contributes additional risk of infection. Since nerve ends are incised during this process, areas of skin on the distal (away from the spine) side of the incision incur nerve anesthesia (dead skin sensation) and proprioceptive loss. Propriceptive loss in the knee can result in gait anomalies, variations in foot alignment, and abnormal wear patterns of the cartilage covered femoral condyles, tibial plateau, or of the menisci.
Another potential complication of BTB harvest is residual pain and discomfort which is separate from the added risk of patellar fracture due to stress risers created during bone plug harvest. Fracture injuries to the patella require significant effort to resolve pathology and related symptoms. These problems of graft harvest are significant enough to have fostered the creation of specialized instrumentation and surgical techniques to minimize both harvest site pain and risk of fracture. Despite advances in autograft bone-plug harvest and defect grafting, pain is a persistent complaint and the risk of patella fracture has not been eliminated.
Another potential complication of common BTB harvest methods is graft fiber relative-width problems that contribute to graft weakness and failure. This occurs when one or both of the harvested bone-plugs is mismatched to the tendon fibers, such that the relative width is less than the desired width which is equivalent to the width of the bone plug. Another way that relative-width error occurs is if the fibers of the tendon are crosscut in order to connect the two closest ends of the misaligned harvested bone plugs.
Graft fiber relative width problems were significant enough to foster the creation of specialized instrumentation and surgical techniques to minimize this problem. Despite advances in Autograft BTB soft-tissue harvest, graft elongation and graft failure still occur and the risk of patellar tendon rupture has not been eliminated.
Another type of autogenous graft used is either or both of the semi-tendinosus, or gracilis (hamstring), the use of which, in addition to the incision complications described previously, includes the risk of harvest site amputation resulting in a graft that is too short to use. Harvest site weakness can produce mobility restrictions and some specific movement incapacity. An additional complication with this type of graft relates to its mode of fixation. Without a bone plug at either end, interference screw fixation, imposed by a headless screw applying lateral force to a boneplug inside the tunnel wall, is not a possibility. Consequently, a staple, screw with washer over a post, or use of a suture attached to an endo button will produce reduction in graft to tunnel wall non-union/non-incorporation from the bungee effect (consistent elongation and contraction under continuous use loading and unloading cycles).
Hamstring harvest and fixation complications were significant enough to foster the creation of specialized instrumentation and surgical techniques to minimize these problems. There has been some limited use of direct interference screw to graft fiber fixation used in lieu of staple, screw with washer over a post or use of a suture attached to an endo button. Despite advances in autograft hamstring harvest, graft elongation, risk of harvest site amputation, non-union/non-incorporation, and graft failure has not been eliminated.
A solution devised to solve fixation problems associated with hamstring use was the incorporation of bone plugs into a looped, double-thick hamstring graft construct. Harvested hamstrings are approximately 2 to 3 times the length and slightly larger than half the diameter required for an ACL substitutes. Consequently, they do not have the same strength as an ACL when compared directly. By folding the hamstring in half, over onto itself, more appropriate lengths and graft strength are obtained. Use of a folded hamstring graft requires some method of fastening the graft to itself. Prior art solutions accomplished this by hand with the use of surgical sutures using various patterns of stitching. Not only is this method of graft construction laborious and tedious, it is complicated by the material itself which is slippery to handle or hold, and the collagen fiber cell matrix resists uniform insertion of the suture needle. These factors add time to the operation, the graft preparation portion of which is but one part.
During the surgery, various means are implemented to reduce risk to the patient while balancing the needs of the surgeon to accomplish the procedures. During ACL reconstruction, there are two specific elements of risk that are typically associated with the surgery. The patient is anesthetized by the use of general anesthesia for reflex and pain control, and a tourniquet is applied to the leg to control bleeding in the surgical region. Generalized goals during the development of arthroscopic instrumentation and techniques for ACL reconstruction has been to reduce the time element of the procedure while improving the efficacy of the technique. By reducing the time element of the procedure, risks associated with general anesthesia and tourniquet use are reduced, and the safety of the procedure for the patient is improved.
One such time element area that remains to be improved is with graft preparation. Problems arise because of the difficulty of running needles through bone both in terms of the mechanics and the accuracy of the procedure, necessitating pre-drilling of suture holes. More prosaically, needles break, physicians run the risk of needle punctures to themselves and to other sites of the patient, and because of its consistency, the ligament replacement often slips out of place before it can be secured. In addition, the sutures remain in the patient indefinitely.
A bioabsorbable implantable device for replacing sutures in construction of a composite graft in ligament replacement surgery is disclosed. The device has a female component and a male component. In one embodiment the components of the device are in the shape of a rivet. In another embodiment, the components of the device are in the shape of a staple. In yet another embodiment, the female component may contain unidirectional teeth on an interior surface and the male component may contain opposing unidirectional teeth on an external surface. In such an embodiment, the device forms a circle when the male component is inserted into the female component. The inner arc of the circle can contain protruding spikes for affixing to the patient. In order to increase the diameter of the circle two such devices may be joined together, wherein the male component of a first device is inserted into the female component of the second device.
The implantable device may be composed of a plurality of bioabsorbable materials. In some embodiments, the bioabsorbable device contains one of a group of compounds comprising polydextrolactic acid, polylevolactic acid, pologlycolides, and polydioxanone.
The bioabsorbable device may include a securing device. The securing device may include a first and second arms connected pivotally to one another. Each arm has a distal and a proximal end that define a recess. The distal end of the second arm further comprises a cannulated cylinder wherein the cannulated cylinder is attached along the recess side of the second arm such that the cylinder is parallel to the longitudinal axis of the second arm. The cannulated cylinder also has unidirectional teeth along the inner surface of the cylinder. The securing device also includes an expandable and contractible loop connected to the first and second arms. The loop includes a linear flexible band having a first ringed end and a second non-ringed end and an inside and an outside surface. The outside surface has unidirectional teeth on the second non-ringed end. There is a rigid connection between the first ringed end and the outer surface of the flexible band such that the plane of the ring is essentially perpendicular to the tangent of the flexible band at the connection point. The loop also includes a lariat-like conformation such that the second non-ringed end is threaded through the first ringed end such that the inside surface of the second end is juxtaposed to the outside surface of the first end within the ring. There is a fixed connection between the first ringed end of the circular loop and the distal end of the first arm such that the first ringed end is connected to the recess-side of the first arm and essentially perpendicular to the longitudinal axis of the first arm. The securing device also includes a movable connection between the non-ringed end of the circular loop and the distal end of the second arm wherein the non-ringed end of the circular loop is threaded through the cannulated cylinder at the distal end of the second arm such that the unidirectional teeth on the outside surface of the non-ringed end of the circular loop are capable of being engaged by the opposing unidirectional teeth within the cannulated cylinder at the distal end of the second arm as the recess between the two arms is decreased. The securing device also includes a mechanism for expanding the dimension of the circular loop after it has been contracted.
In yet another embodiment, the bioabsorbable device is a surgical clamp. The clamp includes a pair of opposing clamping members for engaging tissue. A first arm of the clamp is attached at its distal end to one clamping member and a second arm is attached at its distal end to the opposite clamping member. The first and second arms are pivotably connected to one another for variably adjusting a distance between the respective clamping members. The clamping members have mortises complementary to bioabsorbable graft fastener shapes along the inner surface of the clamping members.
In one embodiment, each of the clamping members is arcuate in shape. In another embodiment, the clamping members are parallel to each other. The mortises of the clamp may be complementary to a circlage-type graft fastener. In another embodiment, the mortises are complementary to a rivet-shaped graft fastener. In yet another embodiment, the mortises are complementary to a stapler-shaped graft fastener. The surgical clamp may include a locking mechanism for securely maintaining an engagement between the clamping members. In certain embodiments one clamping member is sized to partially receive the other clamping member.
The bioabsorbable device may be inserted using an implantable device insertion station. The station may include a tensioning track, a pair of blocks for inserting bioabsorbable implantable devices which are separated along the tensioning track where each block has a chamber for accommodating a bone block and openings for bioabsorbable implantable devices on opposite sides of the block sufficiently large to expose the tendons and accommodate the implantable devices. The implantable device openings of the opposite sides are thus being aligned with one another with the chamber therebetween. The station also includes restraints for holding the implantable device blocks an adjustable distance apart from one another along the tensioning track.
Certain embodiments of the invention may also include an instrument for perforating a tendon/bone complex of a prepared composite graft. The instrument includes a drill and a grafting table. The grafting table includes a device for immobilizing the composite graft wherein the two parallel opposite tendon/bone complexes are exposed, and a guidance device for guiding the placement of the drill along the exposed tendon/bone complex of the composite graft wherein the graft may be placed through one of a plurality of channels. The channels being sized to accommodate different widths and types of grafts.
In another embodiment, the bioabsorbable fastener may be part of a preformed package containing either sized components for constructing a bone tendon bone graft or a preconstructed graft for use in reconstructive surgery. The package includes a sterile container that holds the bone plugs, ligament, and bioabsorbable fasteners. The sterile container may be sectioned and may include sterilized fluid for preserving the ligament and/or the bone plugs. In some embodiments the packaging may be hermetically sealed. The package may have separated allogenic graft components or the ligament or bone plug composition may be formed from man-made materials. The packaging also includes markings that indicate sizing of the ligament and of the bone plugs. More specifically, the sizing may indicate the width and length of the ligament.
In one embodiment, the graft may be made in the following manner. A bone block drill guide having a central column and first and second parallel cylindrical columns intersecting opposite side of the central column equidistant from the center of the of the center column is placed over a bone block. The first and second cylindrical columns each have a center and the centers of the central column and the first and second columns all are aligned. The bone block is drilled to create first and second parallel grooves in opposite sides of the bone block. A ligament replacement is attached to the bone block and looped about the bone block along the first and second grooves. The ligament replacement is then tensioned appropriately. The ligament replacement is attached while tensioned to the bone block using a bioabsorbable implantable device.
In another embodiment of the method, the method further requires inserting the first and second bone plugs along with the at least one ligament replacement each into an implantable device insertion block. The bone plugs and the at least one ligament replacement are accommodated in a compatible chamber on each implantable device insertion block and the implantable device openings are aligned on opposite sides of one another with the chamber therebetween. A stop pin is inserted into each of the implantable device insertion blocks so as to keep each bone plug within its respective implantable device insertion block. Simultaneous pressure is applied to opposite sides of the bone plugs at the exposed surfaces of the opposing bioabsorbable implantable device components, thereby locking the ratchet teeth of each component together to achieve the desired clamping force for the implantable device and securing the at least one ligament replacement to the first and second bone plug.
In various embodiments of the method, the bioabsorbable implantable device is shaped like a rivet or a staple. In other embodiments the bioabsorbable device completes a circle when the male component is inserted into the female component. The method may employ any of the described bioabsorbable fastening devices.
The bioabsorbable implantable device may be used to secure ligaments to the bone plugs or for holding the ligament strands together. In the method the ligaments and bone plugs may be made from autogenous, allogenic or man-made materials. In one embodiment, the graft is prepared prior to surgery as a pre-fabricated graft.
The invention may also be embodied as a package for use in reconstructive surgery. The package includes a sterile container for holding at least a graft that is of a predetermined length and width. The packaging is marked as to the graft size including the width and the length. The graft may be an autogenous, allogenic or man-made tendon. The package also includes one or more bioabsorbable implantable devices for use in constructing a bone tendon bone graft. The graft may reside with sterilized fluid within the sterile container and the container may be hermetically sealed. In certain embodiments, the package may also include a pair of bone blocks. The graft may include marking indicating the location for attachment of the bone blocks. The bone blocks may be predrilled having a cavity for inserting the tendon there through. The bone blocks may also be pre-drilled such that the bone blocks include a grove for the tendon to sit in.
The foregoing features of the invention will be more readily understood by reference to the following detailed description, taken with reference to the accompanying drawings, in which:
Definitions. As used in this description and the accompanying claims, the following terms shall have the meanings indicated, unless the context otherwise requires: The term “tendon” shall refer to a soft tissue and shall be synonymous with the term ligament.
The composite grafts described utilize bone cores (plugs) taken from the patient or provided from cadaveric donors, and these plugs are combined with semi-tendinosus or other tendons taken from the patient or provided from cadaveric donors. These combined component composite grafts can be entirely autogenous, entirely allogenic, or a combination of each type resulting in an alloautograft. This construct combines the best aspects of both types of materials. For example, if a coring reamer is used to create the tunnels, the resultant bone core may be used as part of a combined alloautocomposite graft along with some autogenous ligament or tendon. The value associated with this combination relates to both types of materials. Allogenic ligaments or tendons may be selected for their size or number for relative strength considerations. Triple strand or quadruple strand tendons may be used in lieu of double strand configurations to result in strength increases commensurate with the increase in relative thickness of the 3 or 4 multiply stranded over the double strand configurations. The value of the autogenous bone plug as non-dead tissue, is that graft incorporation and remodeling are accelerated via the revascularization process. This process is accelerated by the proximity of live bone to live bone such that earlier bilateral revascularization is facilitated by earlier sclerotic margin formation between the autogenous bone plug and the tunnel walls.
The use of this type of composite alloautograft configuration is limited to reconstructions requiring tunnels that surgeons choose to use coring reamers to create. In instances where fully fluted reamers are used to drill the tunnels, the resultant bone debris is unsuitable for the bone end of a composite graft construct. Under these circumstances an entirely allogenic composite graft may be comprised of a bone cores and ligaments or tendons to pre-specified dimensions for a given patient as required. Furthermore, they may be prefabricated as kits to be assembled in the operating room by surgical staff just prior to or during the procedure. They may also be prefabricated and prepackaged completely at a site specifically suited for this purpose rendering them ready to insert after they are rehydrated or thawed and pretensioned.
Such an approach alleviates some of the problems and risks associated with securing ligament replacement to bone, but not all. Although held in place by tensioning blocks, the suturing step is a tedious and slow one, so the ligament replacement could still slip out of place during the procedure. Also, the bone plugs must still be sutured to the ligament replacement tissue using traditional suture materials. Although a graft table provides pre-aligned holes for guidance of sutures, the procedure still involves needles, and so, the risk of inadvertent punctures is still an issue. An additional difficulty is the uniformity of the interface between the graft component materials and the suture materials and associated knots and suture loop configurations and techniques. The resultant outcome variations attributable to intra or inter surgeon differences combined with inter or intra material differences may produce patient outcome complications specific to these variations. A method by which these variations can be minimized is with the use of bioabsorbable fasteners that are of specific types for various applications of material component fastening. The result of the use of these fasteners is the secure integration of composite materials into a composite graft system that will withstand insertion, fixation, integration, and graft remodeling.
Use of these devices to construct composite grafts serves to decrease risk to patients by reducing the tourniquet and anesthesia time typically added during graft preparation. For composite autograft constructs, it permits the combined use of materials, bone cores and ligaments, to be prepared more uniformly and in less time. Multiple source, allogenic, autogenous, or man-made, composite grafts constructed with these fastening devices can utilize otherwise discarded materials such as cored autogenous bone, or biologically created ligaments such as autogenous cells harvested and grown, or man-made components such as synthetic bone replacement products, to create various combinations of composite grafts entirely independent of any harvest and subsequent complications while also reducing tourniquet and anesthesia time. Entirely allogenic composite grafts can be prepared completely independent of the operating room and can be made ready for assembly or be pre-assembled. These pre-prepared or prefabricated kits only requiring assembly by use of the fasteners or only require hydration, or thawing, and pre-tensioning respectively. Not only does use of these devices help the patient by reducing tourniquet and anesthesia time, but the increased uniformity and customization capacity to match individual patient graft dimension and strength requirements can significantly improve patient outcome efficacy while also being less dependent on the variations and complications associated with graft preparation and harvest instrumentation and techniques.
The replacement tendon is attached to a bone block 10 at each end of the tendon 11 using a fastener 12, which as discussed below is a bioabsorbable fastener. The bone blocks and bioabsorbable fasteners may also be part of a pre-packaged kit, so that a doctor can quickly select a kit for his intended purpose without the need for extracting bone plugs from the patient, thereby decreasing the length of the surgery. As shown in
Referring now to
Similarly, in
Alternatively, a circle-shaped graft fastener 120 as shown in
Similarly, a semi-circle or U-shaped graft fastener 130 as seen in
Note that the above graft fasteners are all designed to be bioabsorbable implantable devices such that when used in conjunction with reconstructive surgery they do not have to be removed at some later date but can be left in the body to degrade over time. Preferred bioabsorbable materials that would be suitable for such devices include polylactic acids such as polydextrolactic acid, polylevolactic acid, polyglycolites and polydioxanoe. The bioabsorbable materials that are listed are only illustrative and other bioabsorbable materials and their stereo isomers along with any combination thereof may be used. For example, two bioabsorbable materials may be combined in order to achieve the proper time for absorption such as polydextrolactic acid which has a fast absorption time may be combined with polylevolactic acid which has a slower absorption time.
Referring now to
Similarly,
Several variations of a circlage-type clamp in accordance with specific embodiments of the present invention are shown in
Yet another variation of a circlage-type clamp can be seen in
If the graft fastener, such as a circle-shaped graft fastener is too rigid and cannot be bent as desired, heat may be applied to increase the flexibility of the bioabsorbable material.
Referring to
To form the essentially two parallel grooves 06 in bone plug 001 for making a composite graft 400, a bone block drill guide 900 in accordance with a preferred embodiment of the invention may be used, and is shown in
The substantially parallel grooves 06 are drilled by inserting bone plug 001 into the center chamber of column 902 formed by opposing curved walls 904. A drill is directed down column 902 along each of drill guide walls 906 in succession. Thus, parallel grooves 06 are formed on opposite sides of bone plug 001. The drill may be equipped with a stop to prevent the drill from being directed too far down through column 902 where it may contact the table beneath. A drill bit inserted through holes 912 can be easily directed through the center of groove 06 along the bone plug, thereby drilling implantable device hole 912 from one groove through to the opposite groove in the bone plug.
A semitendonous tendon 002 and/or gracilis 003 is extended between both of two bone plugs 001, as seen in
An alternative method of making composite graft 400 can be accomplished by use of a graft preparation table such as that of a preferred embodiment 800 shown in
After inserting a bone plug into bone-block drill guide 844, cap 846 is placed into alignment over the guide. The longitudinal grooves are drilled by inserting the drill bit down through holes 848 in cap 846. After drilling the grooves, cap 846 is removed. The bone block can be removed by lifting bone-block drill guide 844 off graft preparation table 840 and pushing the bone block out of the guide. Graft preparation table 840 may be additionally provided with sizing tubes 850 of different diameters. The sizing tubes are useful in determining the diameter of a bone block. A linear scale 852 may also be included for permitting length measurements.
Attaching semitendonous tendon 002 and gracilis 003 in a loop about two bone blocks 001 completes composite graft 400. Implantable device blocks 860 and 861 assist in this process. An implantable device block 860 as shown in
Implantable device block 860 is fixed in position on the track and implantable device block 861 is fixed to ratchet rod 868. Ratchet rod 868 has a series of grooves spaced along its length and travels in a tube parallel to track 864. The tube includes ridges along its inner circumference that engage walls of the grooves on ratchet rod 868. The ridges and grooves prevent ratchet rod 868 from moving attached implantable device block 860 toward implantable device block 861. The tension on the semitendonous tendon and gracilis loop can be increased by pulling out the ratchet rod 868 to achieve the desired tension. To release the tension, ratchet rod 868 is rotated to disengage the grooves from the ridges. Ratchet rod 868 may then be pushed back into its tube.
As can be seen in
Insertion of implantable devices such as 100 and 110 may be facilitated by use of clamps such as those shown in
While the above methods discuss the making of a composite graft such as 400 using autogenous or allogenic bone for the source of bone plug 001, it is envisioned that synthetic graft material could also be used for both the bone plug and ligament replacement tissues. In addition, it is envisioned that totally soft tissue grafts can be made in conjunction with specific embodiments of the present invention, particularly by using implantable devices such as 120 and 130 for securing the soft tissue together.
The present invention as expressed above may be embodied in other specific forms without departing from the true scope of the invention. The described embodiments are to be considered in all respects only as illustrative and not restrictive.
The present application claims priority from U.S. Provisional Patent Application No. 60/513,652, filed Oct. 23, 2003 having the title “Graft Preparation Table and Bioabsorbable Fasteners for Preparing and Securing Ligament Replacement Grafts,” which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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60513652 | Oct 2003 | US |