JP2022174290A - Intra joint stabilization construct - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide devices and methods of use pertaining to intra joint stabilization.

SOLUTION: Embodiments include a number of suture returning and suture locking anchors that feature elongated sleeves configured to protect associated bone tunnels from suture wipering, which results in abrasion and enlargement of the bone tunnel and leads to migration of the suture anchors. Embodiments also include suture locking anchors that lock via an interference fit between the suture strand and a receiver of the anchor and a set screw, where the receiver and the set screw each feature several gradual, opposing tapers to facilitate gradual proximal-to-distal gripping and releasing of the suture strand to achieve an optimal locking force while preventing severing of the suture strand.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2023,JPO&INPIT

Description

Background Ligaments interconnect the bones of the skeletal system and are involved in the stabilization and kinematics of skeletal joints. A variety of disorders can occur that result in impaired ligament function. Such disorders include, for example, partial and complete tears and detachments of bone where ligaments attach to bone. Ligament disorders occur throughout the skeletal system.

As an example, the human ankle 100 is a complex junction of multiple bones and soft tissues, as shown in FIGS. 1-3. The ankle includes the joints between the tibia 102 , fibula 104 and talus 106 . The joint between the tibia 102 and fibula 104 is a ligamentous or slightly mobile joint in which the bones are held together by connective tissue. The ligamentous syndesmosis between the tibia and fibula includes the anterior inferior tibiofibular ligament (AITFL) 110, the posterior inferior tibiofibular ligament (PITFL) 112, and the interosseous ligament (IOL) 114 (FIG. 3). The synesthesia ligaments are often injured in severe ankle sprains. Other vulnerable ligaments of the ankle joint are the anterior talofibular ligament (ATFL) 120, the posterior talofibular ligament (PTFL) 122, and the deltoid ligament complex, which includes the superficial and deep deltoid ligaments, among others. Includes body 124 .

Current implants, devices, and methods used to reinforce ligaments and promote healing and normal joint function present many challenges and need improvement.

SUMMARY This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key aspects or essential aspects of the claimed subject matter. Furthermore, this Summary is not intended to be used as an aid in determining the scope of the claimed subject matter. One embodiment provides an anchor for use in forming a flexible synthetic strand structure within a bone tunnel drilled through a first bone portion, the bone tunnel extending through the first bone. It has a first end adjacent the first surface of the portion and a second end near the second surface of the first bone portion. The anchor is (1) a head having proximal and distal sides, the distal side adapted to abut a first surface of a first bone portion around a first end of the bone tunnel; (2) a longitudinal shank projecting distally from the head from a proximal end attached to the head to a distal end, the longitudinal shank defining a longitudinal axis; including a shank configured to be inserted into the bone tunnel from a first end of the bone tunnel toward a second end of the bone tunnel, (a) an axial bore extending along the longitudinal axis; (b) the length of the shank is close to the length of the bone tunnel; Entering and exiting the axial bore at the distal end of the shank, the shank provides a bone tunnel protection sleeve that prevents lateral movement of the flexible synthetic strands relative to the bone tunnel, thereby allowing the shank to move within the bone tunnel. prevent bone wear.

Another embodiment provides a knotless fixation system for securing a flexible synthetic strand to a bone tunnel drilled through a first bone portion, the bone tunnel extending through the first bone portion. has a first end adjacent the first surface of the bone portion of the body and a second end near the second surface of the first bone portion. The fixation system includes fixation anchors and set screws. The fixation anchor includes (1) a head, (2) a longitudinal shank projecting distally from the head, the shank defining a proximal portion, a distal portion, and an axial bore extending therebetween. a shank defining a longitudinal axis and configured for insertion into the bone tunnel from a first end of the bone tunnel toward a second end of the bone tunnel; 3) a receiver formed in the proximal portion of the shank, the receiver having a proximal portion oriented at a proximal taper angle, a medial portion oriented at an intermediate taper angle, and a distal taper angle; A receiver having internal threads extending across a distal portion oriented at . The set screw is an external thread extending through a proximal portion oriented at opposing proximal taper angles, an intermediate portion oriented at opposing intermediate taper angles, and a distal portion oriented at opposing distal taper angles. and the proximal, intermediate, and distal taper angles of the receiver and the opposing proximal, opposing intermediate, and opposing distal taper angles of the set screw are determined when the set screw is rotationally inserted into the receiver. a gradual increase in proximal compressive force applied to the length of the flexible synthetic strand extending between the proximal and intermediate portions of the set screw and receiver when the set screw and receiver are , configured to provide a progressive decrease in the distal compressive force applied to the length of the flexible synthetic strand extending between the intermediate and distal portions of the receiver and setscrew.

Yet another embodiment is between a first bone portion having a first bone tunnel defining a longitudinal axis and a second bone portion having a second bone tunnel about the longitudinal axis. Provides an internal structure that stabilizes the joint. The internal structure has first and second opposing ends under tension between a first fixation portion within the first bone tunnel and a second fixation portion within the second bone tunnel. The first fixation portion includes a fixation anchor and a threaded set screw. The fixation anchor is (1) a head having a proximal side and a distal side, the distal side being a first surface of a first bone portion around a first end of a first bone tunnel; (2) a longitudinal shank projecting distally from the head, the shank having a proximal portion, a distal portion and an axial bore extending therethrough; , the shank is inserted into the first bone tunnel from the first end of the first bone tunnel toward the second end of the first bone tunnel adjacent the joint, the shank being inserted into the first bone tunnel; and a distal portion of the shank abuts the second surface of the first bone portion when the shank is inserted into the first bone tunnel. A shank is included that extends to a second end of one of the bone tunnels, the shank providing a bone tunnel protection sleeve.

Additional objects, advantages, and novel features of the technology will become apparent, in part, from the ensuing description, and, in part, will become apparent to those skilled in the art from the ensuing discussion, or It can be learned from the practice of the technology.

Non-limiting and not wholly exhaustive embodiments of the present invention, including preferred embodiments, are described with reference to the following figures, wherein like reference numerals refer to like numerals throughout the various figures unless otherwise specified. refers to the part of Exemplary embodiments of the invention are shown in the drawings.

Fig. 2 is a right side view of a human ankle joint; 1 is a front view of a human ankle joint; FIG. FIG. 2 is a rear view of a human ankle joint; FIG. 12A is a top view of one embodiment of a button-like suture turn anchor. FIG. 10 is a side view of one embodiment of a headless threaded suture turn anchor. FIG. 10 is a perspective view of one embodiment of a polyaxial suture turn anchor. FIG. 10 is a perspective view of one embodiment of a polyaxial suture turn anchor. FIG. 12A is a front view of one embodiment of a polyaxial suture turn anchor. FIG. 12A is a side view of one embodiment of a multiaxial suture turn anchor. FIG. 12A is a rear view of one embodiment of a polyaxial suture turn anchor. FIG. 12A is a side view of one embodiment of a multiaxial suture turn anchor. FIG. 12A is a cross-sectional view of one embodiment of a polyaxial suture turn anchor. [0013] Fig. 4A is a side view of one embodiment of a suture fixation anchor; [0012] Fig. 4 is a front view of one embodiment of a suture fixation anchor; [00023] Fig. 3A is a cross-sectional view of one embodiment of a suture fixation anchor; 1 is a perspective view of one embodiment of a suture fixation anchor; FIG. 1 is a perspective view of one embodiment of a suture fixation anchor; FIG. [0012] Fig. 4 is a front view of one embodiment of a suture fixation anchor; FIG. 14 is a rear view of one embodiment of a suture fixation anchor; FIG. 20 is a cross-sectional view of a receiver in a suture locking configuration of the suture locking anchor of FIGS. 13-19; 21 is a cross-sectional view of the receiver of FIG. 20 with a set screw inserted therein to form an interference fit between the suture strand, the receiver and the set screw; FIG. 22 is a front view of the set screw of FIG. 21, without the screw; FIG. Figure 22 is a cross-sectional view of the set screw and receiver of Figure 21, with the screw removed; FIG. 12 is a perspective view of one embodiment of a threaded suture fixation anchor having a head that is countersunk. FIG. 10 is a perspective view of one embodiment of a button suture anchor having a head that is countersunk. 1 is a perspective view of one embodiment of a polyaxial suture fixation anchor; FIG. 1 is a perspective view of one embodiment of a polyaxial suture fixation anchor; FIG. FIG. 10 is a side view of one embodiment of a polyaxial suture fixation anchor; [0013] Fig. 4A is a cross-sectional view of one embodiment of a polyaxial suture fixation anchor; FIG. 20 is an exploded view of one embodiment of a reverse torque anchor drive instrument in use with the suture fixation anchor of FIGS. 13-19; FIG. 11 shows a partial cross-sectional view through the sacrum parallel to the anatomical transverse plane of the pelvis, surgical sequence for reinforcing a sacroiliac fracture joint through a blind bone tunnel using an embodiment of the disclosed instrument; It is a figure which shows the process of. FIG. 11 shows a partial cross-sectional view through the sacrum parallel to the anatomical transverse plane of the pelvis, surgical sequence for reinforcing a sacroiliac fracture joint through a blind bone tunnel using an embodiment of the disclosed instrument; It is a figure which shows the process of. FIG. 11 shows a partial cross-sectional view through the sacrum parallel to the anatomical transverse plane of the pelvis, surgical sequence for reinforcing a sacroiliac fracture joint through a blind bone tunnel using an embodiment of the disclosed instrument; It is a figure which shows the process of. FIG. 34 provides a flowchart detailing the surgical sequence illustrated by FIGS. 31-33; FIG. FIG. 10 is a side view of one embodiment of a ligamentous coupling tightening structure for the anterior inferior tibiofibular ligament (AITFL) using an embodiment of the disclosed instrument; 36 provides a flow chart illustrating an exemplary method of operation for forming the ligamentous bond tightening structure of FIG. 35; FIG. [0022] Fig. 3 is a side view of another embodiment of a ligamentous binding tightening structure for AITFL using an embodiment of the disclosed instrument and incorporating a bone plate; FIG. 36 provides an illustration of the ligamentous binding clamping structure of FIG. 35, each showing progressively longer anchor sleeves that reduce the free range of the suture extending between the sleeves. FIG. 36 provides an illustration of the ligamentous binding clamping structure of FIG. 35, each showing progressively longer anchor sleeves that reduce the free range of the suture extending between the sleeves. FIG. 36 provides an illustration of the ligamentous binding clamping structure of FIG. 35, each showing progressively longer anchor sleeves that reduce the free range of the suture extending between the sleeves. FIG. 2A is a side view of a human ankle with a fracture of the fibula diaphysis. 42 illustrates the steps in a surgical sequence for the repair of a combined fibular fracture and reinforcement of the synesthesia joint between the tibia and fibula, shown in FIG. 41, using an embodiment of the disclosed instrument; FIG. is. 42 illustrates the steps in a surgical sequence for the repair of a combined fibular fracture and reinforcement of the synesthesia joint between the tibia and fibula, shown in FIG. 41, using an embodiment of the disclosed instrument; FIG. is. 42 illustrates the steps in a surgical sequence for the repair of a combined fibular fracture and reinforcement of the synesthesia joint between the tibia and fibula, shown in FIG. 41, using an embodiment of the disclosed instrument; FIG. is. 42 illustrates the steps in a surgical sequence for the repair of a combined fibular fracture and reinforcement of the synesthesia joint between the tibia and fibula, shown in FIG. 41, using an embodiment of the disclosed instrument; FIG. is. 42 illustrates the steps in a surgical sequence for the repair of a combined fibular fracture and reinforcement of the synesthesia joint between the tibia and fibula, shown in FIG. 41, using an embodiment of the disclosed instrument; FIG. is. 42 illustrates the steps in a surgical sequence for the repair of a combined fibular fracture and reinforcement of the synesthesia joint between the tibia and fibula, shown in FIG. 41, using an embodiment of the disclosed instrument; FIG. is. 42 illustrates the steps in a surgical sequence for the repair of a combined fibular fracture and reinforcement of the synesthesia joint between the tibia and fibula, shown in FIG. 41, using an embodiment of the disclosed instrument; FIG. is. FIG. 49 provides a flowchart detailing the surgical sequence illustrated by FIGS. 42-48; FIG. FIG. 49 shows an alternative step in a surgical sequence for forming a combined repair and reinforcement structure similar to that shown in FIG. 48; FIG. 49 shows an alternative step in a surgical sequence for forming a combined repair and reinforcement structure similar to that shown in FIG. 48; FIG. 49 shows an alternative step in a surgical sequence for forming a combined repair and reinforcement structure similar to that shown in FIG. 48; FIG. 49 shows an alternative step in a surgical sequence for forming a combined repair and reinforcement structure similar to that shown in FIG. 48; 54 provides a flow chart detailing the surgical sequence illustrated by FIGS. 50-53; FIG.

DETAILED DESCRIPTION The embodiments are described more fully below in sufficient detail to enable those skilled in the art to implement the system and method. Embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Therefore, the following detailed description should not be taken in a limiting sense.

The technology described herein relates to devices used to provide ligament reinforcement and fracture repair structures and corresponding methods of use. Embodiments include several suture wrap anchors, suture fixation anchors, anchor fixation drivers, bone protection sleeves, and intra-articular, constructed via surgical methods using the instruments and instruments described herein. Including ligament strengthening and/or fracture repair.

Disclosed instruments and/or structures may be, for example, sutures, suture tapes, cables, or other suitable flexible synthetic strands (hereinafter "flexible strands", "flexible synthetic strands"). or "sutures") and/or may be used.

Suture Wrap Anchors FIGS. 4-5 show examples of suture wrap anchors. In FIG. 4, suture turn anchor 200 has a generally flat disk-shaped body 202 in the form of a button with a plurality of holes 204 extending therethrough. A suture 206 can be passed through the hole 204 to secure the button to the suture. Suture 206 may be passed through a hole or tunnel in the bone, after which anchor 200 abuts the surface of the bone adjacent the hole to prevent the suture from pulling through the hole. A suture 206 is threaded through one of the holes 204 in the anchor body in a first direction indicated by arrow 207 and then through another of the holes 204 in a second, opposite direction indicated by arrow 209 . so that the ends of suture 206 are provided together, on a common side of anchor 200 and extending away from anchor 200, such that anchor 200 is pulled back through one of the sutures. It is an example of a folded anchor.

Suture wrap anchors may be used, for example, when sutures from another portion of the augmentation procedure need to be secured and tensioned using a unilateral approach to the bone. The suture may have a first end and a second free end secured to another securing structure. The second end may be threaded back through the suture cuff anchor so that pulling on the second end places tension on the reinforcing structure. Suture wrap anchors can also be used to provide two ends or loops of suture that are tensioned without sliding through the implant.

FIG. 5 shows another embodiment of a suture turn anchor 270 in the form of a headless screw including a shank 274 with external helical threads 275 . Shank 274 includes a distal first transverse bore 278 , an axial bore 282 opening at the proximal end of shank 274 , a second transverse bore 284 , and a relief groove 286 . From the proximal end, the suture is threaded through the axial hole 282, exits one of the openings of the second lateral hole 284, passes through the first lateral hole 278, and exits the other one of the openings of the second lateral hole 284. Entering and exiting the shaft hole 282, the suture is threaded into the proximal portion of the shank. A relief groove 286 may connect the openings of the first and second transverse holes 278 , 284 on each side of the shank 274 . The relief groove 286 is intended to allow the suture to pass from the axial hole 282 to the first transverse hole 278 while protruding little or not at all from the outer wall of the shank 274 to protect the suture from abrasion. Allowing the suture to slide more easily while allowing it to be threaded and tensioned. A driver may be received in axial bore 282 for driving the screw into bone.

6-12 illustrate an example of a polyaxial suture turn anchor 920. FIG. In this embodiment, anchor 920 is a two piece anchor with separate washer 922 and shank 924 . Shank 924 extends from a proximal end at washer 922 to a distal end spaced from washer 922 and includes one or more transverse holes through which sutures or flexible synthetic strands may be passed. In this embodiment, the shank 924 includes first transverse holes 938 that form opposing openings on opposite sides of the shank 924 through which the suture passes to provide suture cuffs. be done. When the washer 922 abuts the bone, the suture is pulled toward the distal edge 940 of the hole, allowing the suture to be tensioned. The shank further includes an axial bore 942 extending from its distal end opening toward its proximal end. A second lateral hole 944 extends through the shank 924 forming opposing openings on opposite sides of the shank 924 and is distally offset from the first lateral hole. A second lateral hole 944 communicates with the axial hole 942 .

A suture is threaded from the distal end through the axial hole 942, exits one of the openings of the second transverse hole 944, passes through the first transverse hole 938, and through the other opening of the second transverse hole 944. through and out of axial hole 942 so that the suture is threaded into the distal portion of shank 924 . Anchor shank 924 may further include undercut grooves 946 connecting the openings of first and second lateral holes 938 , 944 on each side of shank 924 . The undercuts protect the suture from abrasion while the suture passes from the axial hole 942 to the first lateral hole 938 while protruding little or none from the shank side. allowing the suture to slide more easily while being threaded and tensioned.

In the example of FIGS. 6-12, washer 922 includes a hole 926 formed therethrough and a spherical seat 928 formed adjacent hole 926 . Shank 924 has a head 930 with a spherical seat 932 on its underside adjacent the shank. Spherical seats 928 and 932 mate to allow washer 922 to assume a range of angles relative to shank 924 such that when shank 924 is inserted and advanced into a bone tunnel, A washer 922 abuts the bone surface and can be angled to match the angle between the bone tunnel and the bone surface. The adjustable polyaxial relationship between shank 924 and washer 922 allows washer 922 to be placed in a low profile and close to bone.

Suture Retention Anchors FIGS. 13-30 show examples of suture retention anchors. 13-19 are several views of a suture fixation anchor 300 having a button-like head 302 and a stepped cylindrical shank 304 projecting outwardly from the distal side of the head 302 and defining a longitudinal axis 306. indicates Axial bore 308 extends through anchor 300 . A proximal portion 310 of the shank has a larger diameter than a distal portion 312 of the shank 304 . Proximal portion 310 includes internal threads 314 configured to receive external threads 334 of set screw 316 to secure a suture within axial bore 308 .

In use, one or more sutures 318, or other flexible synthetic strands, are threaded through the shaft hole 308, tensioned, and then held in place by inserting the setscrew 316. It is secured, creating an interference engagement between suture 318 , threads 334 of set screw 316 , and threads 314 of proximal portion 310 of shank 304 .

In the example of FIGS. 13-19, the head 302 is mounted at a non-perpendicular angle to the shank 304 to accommodate a suture path through the bone that is non-perpendicular to the surface of the bone against which the head 302 abuts. . In this embodiment, the head 302 has supplemental suture holes 320, 322 extending through the head 302 from proximal to distal to allow additional sutures to be passed through the head 302. , 324. Undercut grooves 321, 323, 325 are provided on the distal surface of head 302 and communicate with supplemental suture holes 320, 322, 324 for additional sutures between head 302 and the underlying bone. provide an escape for

As shown in FIGS. 13-19, the head 302 is generally elliptical and provides a smooth surface to the overlying soft tissue to reduce soft tissue irritation. The shank 304 provides a tubular extension into the bone tunnel to protect the suture from abrasion from the bone and to protect the bone tunnel from abrasion or cutting from the suture.

A conventional button-type fixation anchor sits outside the bone at the end of the bone tunnel and is secured by a suture knot tied at the surface of the button and positioned to stimulate the surrounding soft tissue. Over time, the suture tends to erode the bone at the exit of the bone tunnel, causing the button to sink or collapse into the bone. Physicians have recorded up to 10 mm of button-to-bone transition. As the bone deteriorates and the suture loosens, the button also generates a level of back-and-forth translational motion on the surface of the bone, which stimulates both the bone and the surrounding tissue.

Embodiments of suture fixation anchor 300 avoid these complications. The shank 304 extends into a tightly fitted bone tunnel and the shank 304 is press fit into the cortex or hard outer shell of the bone. This increased amount of surface area between the shank and the cortex of the bone, as well as the protective sheath that the shank 304 and head 302 provide for the sutures 318 at the bone surface, and the knotless fixation mechanism, secure the implant and the head. It helps prevent cutting 302 or subsidence into bone tunnels, resulting in a more stable and longer lasting reinforcing structure. Excess suture length 318 is fully trimmable and the resulting suture is flush with anchor head 302 and fixed setscrew 316 to further prevent tissue irritation.

Figures 20-23 show details of the suture anchoring structure of the example of Figures 13-19. FIG. 20 provides an enlarged view of the internal structure of proximal portion 310 of shank 304 and FIG. 21 provides a cross-sectional view of proximal portion 310 of shank 304 receiving set screw 316 . The proximal portion 310 of the shank has a receiver 330 with tapered receiver threads 332 and the set screw 316 has tapered external threads 334 . Both the receiver thread 332 and the set screw thread 334 are rounded knuckle threads. In addition, receiver 330/receiver threads 332 and setscrew 316/setscrew threads 334 feature multiple distinct taper angles transitioning from proximal to distal to provide progressive grasping and release of suture 318. to provide a strong grip on the suture while reducing the risk of suture damage.

To address the taper angle in more detail, FIGS. 22-23 show setscrew 316 and receiver 330 without knuckle threading to better illustrate their taper gradual transition. Set screw 316 is cylindrical at proximal portion 350 and has a relatively small angular taper over its intermediate portion 352 and a relatively large angular taper over its distal portion 354 terminating in a rounded tip 364 . . Receiver 330 has a relatively large angular taper at proximal portion 356 , a relatively small angular taper across its intermediate portion 358 , and is cylindrical at its distal portion 360 . When setscrew 316 and receiver 330 are coupled, they provide progressively less clearance between them from the proximal end of anchor 300 to their middle portion and distally from their middle portion. , to the end of set screw 316, providing progressively more clearance therebetween.

This opposing tapered configuration of set screw 316 and receiver 330 incorporates the Morse taper principle for the connecting components. The opposing conical shapes of set screw 316 and receiver 330 are closely matched or approximated in taper angle at intermediate portions 352, 358, while the opposing shapes of set screw 316 and receiver 330 are closely matched at their proximal portions. 350, 356 and their distal portions 354, 360 differ in taper angle. This arrangement causes the respective surfaces of setscrew 316 and receiver 330 to achieve an interference fit about suture 318 over the intermediate portions 352, 358 of setscrew 316 and receiver 330, and progressively increases proximally. A gentle transition leads to an interference fit and a distal, gradual transition leads out of the interference fit. This gradual transition in compressive force applied to suture 318 positioned between setscrew 316 and receiver 330 provides improved suture anchoring/anchoring strength, while at the same time being accompanied by a greater compressive force transition. reduce the risk of cutting existing sutures 318.

In one embodiment, the setscrew 316 and the intermediate portions 352, 358 of the receiver 330 are the same length and are aligned. In this embodiment, there are three zones or amounts of clearance between the setscrew 316 and the receiver 330, from a relatively large amount of clearance proximally to a relatively small amount of clearance across their midsection to distally. to a relatively large amount of clearance at .

20-23, the set screw 316 has the beginning of its middle portion 352 located distal to the beginning of the receiver middle portion 358, as shown in FIG. , so that the end of set screw middle portion 352 is located proximal to the end of receiver middle portion 358 . This arrangement provides five clearance zones 340 , 342 , 344 , 346 , and 348 for further gradual progression of grasping and releasing suture 318 . Any number of taper angle steps may be provided for setscrew 316 and receiver 330, and any placement of overlap or radius fusion may produce any number of gradual clearance steps, from no gripping on the suture to , maximum grasp, no grasp, may be provided to transition proximally to distally, protecting the suture 318 through progressive increases and decreases in stress applied to the suture 318 .

Referring to FIG. 23, the first zone 340 provides maximum clearance proximally, the clearance between the cylindrical proximal portion 350 of the setscrew 316 and the relatively large angle of the proximal portion 356 of the receiver 330 . decreases distally in the angular difference between. The clearance of the second zone 342 decreases distally by the angular difference between the cylindrical proximal portion 350 of the setscrew 316 and the relatively small angle of the intermediate portion 358 of the receiver 330 . A third zone 344 provides a minimum clearance and corresponds to where the setscrew 316 and the intermediate portions 352, 358 of the receiver 330 meet. The clearance of fourth zone 346 increases distally with the angular difference between the relatively small angle of intermediate portion 358 of receiver 330 and the relatively large angle of distal portion 354 of set screw 316 . Fifth zone 348 provides the greatest clearance distally, the clearance being the angular difference between the relatively large angle of distal portion 354 of set screw 316 and cylindrical portion 360 of receiver 330 . increments.

20-23, the taper of set screw 316 is cylindrical at first proximal portion 350, 10 degrees per side at second intermediate portion 352, and 10 degrees per side at distal portion 354. is 20 degrees per side. Receiver 330 tapers 20 degrees per side at first proximal portion 356 , 10 degrees per side at second intermediate portion 358 , and is cylindrical at third distal portion 360 . The resulting relief angle tapers, corresponding to the five zones 340, 342, 344, 346, 348 shown in FIG. 20 degrees. In this embodiment, the proximal ends 361, 363 of the receiver 330 and setscrew 316 are chamfered, and the distal end 364 of the setscrew 316 is rounded to further eliminate any sharp edges and reduce the length of the suture. Provides a smoother path and easier activation of the screw.

While the embodiment of FIGS. 20-23 features opposing tapers of setscrew 316 and receiver 330, the present invention provides a tapering of suture 318 between setscrew 316 and receiver 330 from proximal to distal. It will be appreciated that any suitable taper configuration that provides a stepwise increase and decrease in compressive force applied to the interference fit is contemplated. For example, set screw 316 may be completely cylindrical through its proximal, intermediate, and distal portions, maintaining the above configuration of receiver 330 . In another example, the proximal, intermediate, and distal portions 350 , 352 , 354 of the setscrew 316 are angled to form an egg-like or football shape, and the receiver 330 The proximal, intermediate, and distal portions 356, 358, 360 may remain cylindrical.

The anchoring configurations described in connection with FIGS. 20-23 provide both knotless and reversible mechanisms for securing suture 318 to anchor 300. FIG. The fixation configuration provides knotless fixation because the interference fit between suture 318 , setscrew 316 , and receiver 330 provides the necessary compressive force to secure suture 318 under tension to anchor 300 . provide, thereby reducing the probability of bone and/or tissue wear and/or deterioration often caused by nodal fixation. In addition, the fixation mechanism protects the integrity of the suture through gradual increases and decreases in stress applied to suture 318, as described above, so that no-node fixation allows set screw 316 to rotate and insert. It is precisely reversible in that it can secure suture 318 to anchor 300 without damaging suture 318 and/or compromising its structural integrity. As a result, the surgeon may anchor and unclamp suture 318 to anchor 300 multiple times to achieve optimal fixation while maintaining confidence in the quality of the final knotless fixation.

Figures 24-25 illustrate additional examples of suture fixation anchors incorporating the tapered, knuckle-threaded suture anchor of Figures 20-23. In FIG. 24, an anchor 370 in the form of a bone screw has a proximal head 371 with an internal driver mechanism 372, an axial through hole 374, and a tapered screw for receiving a set screw 316 as shown in FIG. with receiver 376 . FIG. 25 shows a suture fixation anchor 394 in the form of a button with a proximal head 387 operable to seat in a spherical countersink in a bone plate. Anchor 394 includes an internal driver mechanism 396 and an axial bore 390 and tapered threaded receiver 392 for receiving a set screw similar to that shown in FIG. Each of the respective proximal heads 371, 387 of the anchors 370, 394 are countersunk bone plates in which they are positioned and secured to either the tibia 102 or the fibula 104 (FIGS. 1-3). configured to sit within and be flush with its surface.

26-29 show an example of a polyaxial suture fixation anchor 1440 similar to anchor 300 of FIG. However, the example anchor of FIGS. 26-29 is a two-piece anchor with separate washer 1442 and shank 1444 . The washer has a hole 1445 formed therethrough and a spherical seat 1448 formed adjacent to the hole. The shank 1444 has a head 1450 with a spherical seat 1452 on its underside adjacent the shank 1444 . Spherical seats 1448 and 1452 engage to allow washer 1442 to assume a range of angles with respect to the shank, shank 1444 being inserted and advanced through the bone tunnel, and the washer contacting the bone surface. When mating, the washer may be angled to match the angle between the bone tunnel and the bone surface. The adjustable polyaxial relationship between shank 1444 and washer 1442 allows washer 1442 to be low profile and close to the bone.

FIG. 30 shows counter-torque instrument 960 having hollow shaft 962 and anchor-engaging end 964 . Counter-torque device 960 performs sutureless suture tightening via an interference fit between a set screw, such as set screw 969, and a number of suitable anchors, such as anchors 300, 370, 394, and 1440, described above, for example. can be used to lock the Focusing on anchor 1440 for illustrative purposes, anchor-engaging end 964 of counter-torque device 960 includes spaced-apart prongs 966 . Prongs 966 are engageable with corresponding grooves 1454 formed in head 1450 of shank 1444 of anchor 1440 . This engagement holds the shank 1444 stationary as the set screw 969 is driven or tightened into the anchor 1440 using a suitable setscrew driver inserted through the hollow shaft 962. Provides counter torque force and prevents shank 1444 from rotating. Accordingly, the surgeon may drive the setscrew 969 into the anchor 1440 without fear of inadvertently torquing or impacting the desired angular relationship between the shank 1444 and the washer 1442 of the polyaxial anchor 1440. , as previously described, to allow the washer 1442 to lie flush with the bone. This ability of washer 1442 and/or shank 1444 of anchor 1440 to resist the torsional forces created by the driver and setscrew 969 is pleasing to the surgeon and allows for more effective anchor placement and locking. Bring.

Intra-articular Constructs and Surgical Sequences FIGS. 31-54 are used to internally stabilize or strengthen ligaments across bone joints and/or to stabilize bony segments across fractures. Some methods according to examples of the invention are shown.

Figures 31-33 show a repair structure in which an exemplary device is used to reinforce a fractured bone joint through a "blind hole" bone tunnel in which a first anchor is placed. Fitting, the second anchor follows the first anchor in the blind hole tunnel. More specifically, and in one embodiment, the exemplary instrument is used to repair the sacroiliac joint 2113 to stabilize the pelvis after an anterior-posterior compression fracture. FIG. 34 provides a flow chart illustrating an exemplary method 1500 of reinforcing the sacroiliac joint 2113 according to the steps shown in FIGS.

Referring to FIG. 31, a bone tunnel 250 is formed in the sacrum 2102 through the ilium 2107 and across the unstable sacroiliac joint 2113 (FIG. 34, 1502). A counterbore 254 is formed at the entrance of the tunnel 250 on the surface of the ilium 2107 (Fig. 34, 1504). A first anchor 256 is inserted through tunnel 250 and into sacrum 2102 where it secures a flexible strand such as suture 258 (FIG. 34, 1506). A flexible strand 258 extends from the posterior end of first anchor 256 through tunnel 250 and out of ilium 2107 .

Referring to FIG. 32, flexible strand 258 is placed through second anchor 260, which sits on ilium 2107 (FIG. 34, 1506-1508). A second anchor 260 includes a tubular portion 262 that extends into the tunnel countersink 254 and a washer portion 264 that rests on the iliac surface. 31-33, tubular portion 262 and washer portion 264 are separate pieces that engage at cylindrical seat 266 so that they articulate relative to each other and adaptively engage bone surfaces and tunnel 250. Allows alignment.

To tension the portion of suture 258 extending between anchors 256, 260 (FIG. 34, 1510), the ends of suture 258 can be pulled using a suitable tensioning tool. As a result, and as shown in FIG. 33, the unstable sacroiliac joint 213 is tightened. Suture 258 can then be secured against a second anchor to maintain clamping (FIG. 34, 1512). To secure, a locking set screw 270 may be advanced through the central cannula of the puller and threaded into internal threads 272 formed in the second anchor 260, thereby locking screw 270 and anchor 260 into place. An interference fit between internal threads 272 secures suture 258 to second anchor 260 . The tensioner can then be removed and any excess length of suture 258 can be trimmed off, leaving suture 258 flush with anchor 260 (FIG. 34, 1514).

The sacroiliac joint 2113 repair described in FIGS. 31-34 may be used in place of or in combination with prior art iliac-sacral screws. The adaptive structure shown in Figure 33 is advantageous in that it provides controlled tightening of the unstable joint after placement of the anchor. With the tensioner attached, the joint is tested and the tension is adjusted to the desired stability. Joint tension may be adjusted to any desired value prior to securing suture 258 to second anchor 260 . The locking mechanism is knotless and reversible, allowing subsequent readjustment and relocking as needed and/or desired. The structure places a continuous, uninterrupted flexible member (e.g., suture/flexible synthetic strand 258) across the joint 2113, which is less rigid than a rigid implant that can experience fatigue failure. Make it less vulnerable to destruction.

The structure of Figure 33 may be applied at any desired location relative to the joint. The position of the structure can be more anterior or posterior, or more superior or inferior. A first anchor 256 may be set deeper into the sacrum. A first anchor 256 may be secured from the unstable sacroiliac joint to the cortical bone of the opposing sacrum such that sutures 258 span the sacrum. Multiple structures can be applied to achieve the desired level of stability. The multiple structures may be spaced from top to back and/or from front to back. Additionally, although FIGS. 31-34 refer to reinforcement of the sacroiliac joint 2113 to stabilize the pelvis after anterior-posterior compression fractures, similar methods and devices can be used to stabilize various bone joints in the body. Can be used as needed.

FIG. 35 shows an exemplary device used to reinforce ligaments that extend across a joint between two bones. More specifically, and in one embodiment, FIG. 35 shows a ligamentous coupling tightening structure 1650 for the anterior inferior tibiofibular ligament (AITFL) 110, and FIG. A flow chart is provided showing an exemplary method 1600 of hardening.

Referring to FIG. 35, first a bone tunnel 1652 is formed through the fibula 104 and a second coaxially adjacent tunnel 1654 is formed in the tibia 102 (FIGS. 36, 1602). A first suture cuff anchor 1656 is inserted through the first tunnel 1652 and into the fibula 104 (Fig. 36, 1604). The suture wrap anchor can be, for example, the multiaxial suture wrap anchor 920 described above in connection with FIGS. 6-12. A second suture fixation anchor 1658 is inserted through the second tunnel 1654 and into the tibia 102 (Fig. 36, 1606). Suture fixation anchors can include, for example, the suture fixation embodiments described above with respect to FIGS.

From the right, a flexible strand such as suture 1660 is threaded through second suture fixation anchor 1658 and back through first suture turn anchor 1656 to the first suture fixation anchor. It may be retrograded through 1658 ( FIG. 36 , 1608 ) so that both ends of suture 1660 extend from a second suture fixation anchor 1658 that seats in tibia 102 .

A second anchor 1658 includes a tubular portion 1662 that extends into tunnel 1654 and a washer portion 1664 that rests on the tibial surface. In the example of FIG. 35, tubular portion 1662 and washer portion 1664 are separate pieces that engage in a cylindrical seat, allowing them to articulate with respect to each other to provide tunnel 1654 and surface of tibia 102 . Align each appropriately.

To tension suture 1660 extending between first anchor 1656 and second anchor 1658 (Fig. 36, 1610), the ends of suture 1660 are pulled using a suitable tensioning tool. can be As a result, the synesthesia joints are tightened and the ligaments 110 are strengthened, as shown in FIG. Suture 1660 can then be secured against a second suture fixation anchor 1658 to maintain clamping (FIG. 36, 1612). The tensioner can then be removed and any excess length of suture 1660 can be trimmed off, leaving suture 1660 flush with anchor 1658 (Fig. 36, 1614).

Like the sacroiliac joint repair of FIGS. 31-34, the ligament reinforcement structure 1650 described in connection with FIGS. , providing continuous, uninterrupted strands and controlled tightening of unstable joints after anchor placement. The joint is tested with the tensioner attached and the tension adjusted to the desired stability. Tension may be adjusted prior to anchoring and readjusted as needed and/or desired. The structure places a continuous, uninterrupted flexible member (eg, suture 1660) across the joint, making it less susceptible to failure than rigid implants that may experience fatigue failure.

Structure 1650 of FIG. 35 may be applied to any desired location relative to the joint/ligament. The location of the structure may be more anterior or posterior (eg, may be configured to stiffen the PITFL 112), or may be more superior or inferior. Multiple structures can be applied to achieve the desired level of stability. The multiple structures may be spaced apart from top to bottom and/or from front to back. Further, although FIGS. 35-36 refer to reinforcement of the AITFL 110, similar methods and devices can be used as desired to reinforce any ligament within the body. The exemplary structure may be used with a bone plate 1670, as shown in FIG.

Focusing on FIG. 35, tubular portion 1662 of anchor 1658 functions as a suture sleeve that extends toward the end of second bone tunnel 1654 and the inner surface of tibia 102 . Similarly, tubular portion 1666 of first anchor 1656 functions as a suture sleeve that extends toward the end of bone tunnel 1652 and the inner surface of fibula 104 . Tubular portions/sheaths 1662, 1666 provide protection for the bone tunnel and limit lateral movement, or suture wiping, of suture 1660 within the space between sleeves 1662, 1666. When sleeves 1662 and 1666 extend to the end of bone tunnel 1654/surface of tibia 102 and to the end of bone tunnel 1652/surface of fibula 104, respectively, suture 1660 is flexible only the full length of the natural ligament. and lateral movement or suture wiping is limited to the total length of the natural ligament (eg, 1-2 mm) across the joint between the bones. Because the wiping of the suture over time wears the bone within the bone tunnel and around the bone tunnel edges, the use of anchors featuring a hollow shaft/sheath to accommodate the suture is discouraged. , which in turn reduces bone wear caused by sutures. The further tubular portions/sleeves 1662, 1666 extend into other bones, the less likely such suture wiping and consequent wear may occur.

To demonstrate, FIGS. 38-40 show a given structural compliance (including suture tension, bone slip, compression, bone interface, and other factors, all of which are shown as dashed lines). 1662, 1666 graphically shows that increasing the length of the tubular anchor sleeves 1662, 1666 reduces the amount of suture cutting or wiping that can occur, as opposed to bone overlap, represented here. In other words, as the free extent of suture 1660 between tubes/sleeves 1662, 1666 decreases from that shown in FIG. 38 to that shown in FIG. There is less slippage and less cut into the bones 102, 104 by the suture 1660.

FIGS. 41-47 illustrate the steps of a method 1700 involved in repairing a fibular fracture and reinforcing a synesthesia joint with exemplary instruments and instruments of the present invention, and FIG. 49 illustrates FIGS. 41-52. provides a flow chart illustrating the method 1700, detailed in . By way of background, FIG. 41 shows a side view of a human ankle 100 showing a fracture 116 of the fibula diaphysis 104 .

42, a fracture fixation plate 120 known in the art is secured to fibula 104 to bridge fracture 116 and provide support to fracture 116 while fracture 116 heals (FIG. 42). 49, 1702). Such plates are typically inserted through holes 122 in plate 120 and secured by bone screws (not shown) that extend from plate 120 into the cortical bone on the opposite side of the bone. The embodiments described below allow loops of flexible strands, rather than rigid hardware, to secure bone plate 120 .

Turning to FIGS. 43-44, a first tunnel 127 is formed through the fibula 104 and tibia 102 to stabilize the joint, particularly the interosseous ligament 114, to stabilize the joint across the ligamentous joint. Accept the element (Fig. 49, 1704). A first tunnel 127 is preferably formed adjacent the edge of plate 120 and in the same direction as the natural ligament to reinforce the ligament during healing. Preferably, the first tunnel 127 passes through the fibular eminence 125 and through the centroid of the fibula 104 and tibia 102 at a fixed height. In this embodiment, a first tunnel 127 is formed adjacent the front end of plate 120 . The first tunnel 127 may be spaced from the plate to a greater or lesser extent and/or positioned behind the plate, depending on the surgeon's preference and the position of the plate. In the example of Figures 41-52, the plate 120 is positioned posteriorly to match the preferred path of the first tunnel 127 through the bone.

First tunnel 127 may be formed by drilling, punching, or other suitable tunneling means. The first tunnel 127 can be created freehand or with a guide such as a clamp and drill guide instrument.

Referring to Figure 45, an auxiliary tunnel 126 is formed (Figure 49, 1706). Auxiliary tunnel 126 intersects both hole 122 in plate 120 and first tunnel 127 . A drill may be inserted through a hole in plate 120 , with the plate itself acting as a drill guide for auxiliary tunnel 126 .

46, suture threader 130 is passed through plate 120, auxiliary tunnel 126, and first tunnel 127 so that it exits through plate 120 and tibia 102 (see FIG. 46). 49, 1708). Flexible synthetic strand 132 is then engaged with threader 130 (Fig. 49, 1710). As noted above, the flexible synthetic strands may be high strength sutures, suture tapes, cables, or another suitable flexible synthetic strand.

47, threader 130 is withdrawn through bones 102, 104 and plate 120 to advance flexible strand 132 through bone and plate 120 (FIGS. 49, 1712). Threader 130, or another threader having a flexible strand engaged thereto, is then passed through first tunnel 127, exiting fibula 104 on one end and tibia 102 on the other end ( 49, 1714).

FIG. 48 shows threader 130 being withdrawn through bones 102, 104 to advance flexible strand 132 through first tunnel 127 (FIG. 49, 1716). The flexible strand 132 is now looped around the anterior end of the plate 120 and the two legs of the flexible strand 132 extend across the ligamentous synesthesia joint between the tibia 102 and fibula 104 . The ends of the flexible strands 132 can then be pulled, tightening the synesthesia joints and tensioning them appropriately (Fig. 49, 1718). Tension can be applied manually by pulling directly on the ends of the flexible strands. Alternatively, a tensioning device can be used to apply tension and/or indicate tension. The flexible strand 132 is tied, for example, at the ends over a button anchor, an interference screw is inserted into the first tunnel, and one or more staples are used to tie the ends to the exit hole of the first tunnel 127 . It may be fixed by anchoring to the tibial surface adjacent to the sphincter, or by securing the flexible strands with other knotless anchors.

50-53 show an alternative process for threading the flexible strands 132, and FIG. 54 provides a flow chart summarizing the corresponding method 1800. FIG. Referring to Figure 50, the flexible strand 132 is folded to create a bend 138 between the ends of the strand, preferably approximately in the middle of the strand (Figure 54, 1802). A threader, such as hook 140, is threaded through plate 120, auxiliary tunnel 126, and first tunnel 127 (Fig. 54, 1804). Threader 140 can be threaded in either direction, but it may be easier to first thread plate 120 in the opposite direction to achieve the position shown in FIG. Once the threader is in place, the bend 138 is engaged with the hook 140 (Fig. 54, 1806).

51, hook 140 has been withdrawn through bones 102, 104 and flexure 138 passes through plate 120, auxiliary tunnel 126, first tunnel 127, and exits tibia 102 (see FIG. 51). 54, 1808). A threader, such as threader 130, is inserted through the first tunnel (FIG. 54, 1810) and the free end of flexible strand 132 engages the threader (FIG. 54, 1812).

Figure 52 passes the free end of flexible strand 132 through first tunnel 127 (Figure 54) before the free end of flexible strand 132 is passed through bend 138 (Figure 54, 1816). , 1814), the threader 130 is shown pulled through the bone.

Referring to FIG. 53, the free ends of flexible strands 132 are pulled to transition bends 138 down first tunnels 127 and forward ends of plates 120 and first and auxiliary tunnels 127 and 126 . A girth hitch 144 is formed around the portion of the bone 142 between (FIG. 54, 1818). If desired, a push rod, forceps, or other instrument may be used to push the bend 138 to help move it down the tunnel 127 as the free end is pulled. Forming the illustrated girth hitch 144 may improve the direction of the flexible strands 132 through the bone and reduce the tendency of the flexible strands to apply pressure to the edges of the tunnel. Flexible strands 132 may be tensioned (FIG. 54, 1820) and secured (FIG. 54, 1822) as described above in connection with FIG.

A ligamentous attachment reinforcement sequence according to examples of the present invention achieves a very low profile, with flexible strands wrapping around the plate edges to secure the bone plate, and without rigid hardware spanning the joint, flexible provide reinforcement. These advantages are achieved while avoiding x-ray shadowing of the joint interface. Reinforcement according to embodiments of the present invention may be more anterior or posterior, etc., because the tunnel may be aligned with either the leading or trailing edge of the plate, or offset from either the leading or trailing edge of the plate. , can correspond to different plate positions. Reinforcements according to examples of the present invention are easily modifiable as the flexible strands can simply be cut and the fixation removed from the tibial side of the structure. In particular, the bone plate may be secured to the fibula, as shown, and optionally and/or appropriately to the tibia.

While the above embodiments have been described in language specific to certain structures, elements, configurations, and methodological steps, the technology defined in the appended claims is directed to the specific structures, elements, configurations, and methodological steps described. , configuration, and/or process steps. Rather, the specific aspects and steps are described as forms of implementing the claimed technology. Since many embodiments of the technology can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.

Claims (8)

for stabilizing a joint between a first bone portion having a first bone tunnel defining a longitudinal axis and a second bone portion having a second bone tunnel about said longitudinal axis; an internal structure,
The internal structure has first and second opposite ends tensioned between a first fixation portion within the first bone tunnel and a second fixation portion within the second bone tunnel. a flexible synthetic strand having a portion, the first fixation portion including a fixation anchor and a threaded set screw, the fixation anchor comprising:
A head having a proximal side and a distal side, the distal side abutting a first surface of the first bone portion around a first end of the first bone tunnel. , the head, and
A longitudinal shank projecting distally from the head, the longitudinal shank having a proximal portion, a distal portion and an axial bore extending therethrough, the longitudinal shank comprising: inserted into the first bone tunnel from the first end of the first bone tunnel toward the second end of the first bone tunnel adjacent the joint; A shank has a length approximating the length of the first bone tunnel, and when the longitudinal shank is inserted into the first bone tunnel, the distal portion of the longitudinal shank extends to the length of the first bone tunnel. a longitudinal shank extending to a second end of the first bone portion adjacent a second surface of the first bone tunnel, the longitudinal shank providing a bone tunnel protection sleeve; An internal structure comprising said flexible synthetic strands. 2. The internal structure of claim 1, wherein a threaded receiver is formed on a proximal portion of said longitudinal shank. 3. The internal structure of claim 2, wherein said second fixation portion comprises a second longitudinal shank having a second axial bore formed therein and said second axial bore. a cuff anchor including cuff formations in communication with a bore, wherein the second longitudinal shank is inserted into the second bone tunnel;
The first opposed ends of the flexible synthetic strands enter the fixation anchor through the threaded receiver, exit the fixation anchor through the bone tunnel protection sleeve, and extend into the first and second ends. traversing the joint between bone portions of, through the second axial hole, into the fold anchor, passing around the fold configuration, through the second axial hole, exiting the fold anchor, re-entering the fixation anchor through the bone tunnel protection sleeve, exiting the fixation anchor through the threaded receiver;
the flexible strand is tensioned between the fixation anchor and the turn-up anchor;
The first and second opposing ends of the flexible synthetic strands are fixed to the fixation anchor via the threaded setscrew that is rotationally inserted into the threaded receiver; An internal structure characterized by providing a continuous, uninterrupted length of said flexible synthetic strand extending inwardly across said joint between one and a second anchor. 2. The internal structure of claim 1, wherein said second bone tunnel is a blind hole tunnel and comprises: (1) a turn-up anchor; and (2) pre-attached one of said flexible synthetic strands. one of which is inserted into the blind hole tunnel from the second end of the first bone tunnel adjacent the joint toward the first end of the second bone tunnel; An internal structure characterized by 2. The internal structure of claim 1, wherein the fold anchor further includes a second head having proximal and distal sides, the distal side of the second head extending through the second bone. adjacent the first surface of the second bone portion about the first end of the portion;
A second longitudinal shank projects distally from the second head, the second longitudinal shank having a length approximating the length of the second bone tunnel and the second longitudinal length. when the orientation shank is inserted into the second bone tunnel from the first end of the second bone tunnel toward the second end of the second bone tunnel adjacent the joint; , said second longitudinal shank extends to said second end of said second bone tunnel adjacent a second surface of said second bone portion; provides a second bone tunnel protection sleeve. 6. The internal structure of claim 5, wherein the second head of the fold anchor abuts the first surface of the second bone portion at the second bone tunnel. An internal structure characterized by alignment. 2. The internal structure of claim 1, wherein the head of the fixation anchor is pivotally connected to the proximal portion of the longitudinal shank, the head connecting the first bone tunnel and the first bone tunnel. selectively angled to achieve an anchor angle between the distal face of the head and the longitudinal shank that matches the tunnel angle between the bone surfaces of the head. 2. The internal structure of claim 1, wherein the fixation anchor threaded receiver includes a proximal portion, an intermediate portion, and a distal portion, and wherein the threaded setscrew comprises a proximal portion, an intermediate portion, and a distal portion. and a distal portion, wherein the threaded setscrew is configured for rotational insertion into the threaded receiver between the threaded receiver and a proximal portion and an intermediate portion of the threaded setscrew. a progressively increasing interference fit around the flexible synthetic strands passing through and the flexible synthetic passing between intermediate and distal portions of the threaded receiver and the threaded setscrew; A progressively decreasing interference fit is achieved about the strands, and the progressively increasing interference fit and the progressively decreasing interference fit combine to provide the flexible composite to the fixation anchor. An internal structure characterized by fixing the strands.

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