JP7559022B2 - Intra-articular stabilization structure - Google Patents

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 avulsions of bones where the ligament attaches to the bone. Ligament disorders occur throughout the skeletal system.

As an example, the human ankle 100 is a complex joint of multiple bones and soft tissues, as shown in Figures 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 syndesmotic or slightly movable joint in which the bones are joined together by connective tissue. The syndesmotic joints between the tibia and fibula include the anterior inferior tibiofibular ligament (AITFL) 110, the posterior inferior tibiofibular ligament (PITFL) 112, and the interosseous ligament (IOL) 114 (Figure 3). Syndesmotic ligaments are often injured in severe ankle sprains. Other ligaments of the ankle joint that are prone to injury include, among others, the anterior talofibular ligament (ATFL) 120, the posterior talofibular ligament (PTFL) 122, and the deltoid ligament complex 124, which includes the superficial and deep deltoid ligaments.

Current implants, devices, and methods used to reinforce ligaments and promote healing and normal joint function present many challenges and require 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 or essential aspects of the claimed subject matter. Moreover, this Summary is not intended for use 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 in a bone tunnel drilled through a first bone portion, the bone tunnel having a first end adjacent a first surface of the first bone portion and a second end near a second surface of the first bone portion. The anchor includes: (1) a head having a proximal side and a distal side, the distal side configured to abut a first surface of a first bone portion about a first end of a bone tunnel; (2) a longitudinal shank attached to the head and projecting distally from the head from a proximal end to a distal end, the longitudinal shank defining a longitudinal axis and configured to be inserted into a bone tunnel from the first end of the bone tunnel toward the second end of the bone tunnel, (a) an axial bore extends within the anchor along the longitudinal axis; (b) a length of the shank approximates a length of the bone tunnel; and (c) the shank provides a bone tunnel protection sleeve that prevents lateral movement of the flexible synthetic strands relative to the bone tunnel as they move in and out of the axial bore at the distal end of the shank upon progression to or from a separate strand fixation portion, thereby preventing abrasion of the bone within the bone tunnel.

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 having a first end adjacent a first surface of the first bone portion and a second end near a second surface of the first bone portion. The fixation system includes a fixation anchor and a set screw. The fixation anchor includes: (1) a head; (2) a longitudinal shank protruding distally from the head, the shank having a proximal portion, a distal portion, and an axial bore extending therebetween, the shank defining a longitudinal axis and configured for insertion into the bone tunnel from the first end of the bone tunnel toward the second end of the bone tunnel; and (3) a receiver formed in a proximal portion of the shank, the receiver having an internal thread extending across a proximal portion oriented at a proximal taper angle, an intermediate portion oriented at a middle taper angle, and a distal portion oriented at a distal taper angle. The set screw includes external threads extending across 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, intermediate, and distal taper angles of the set screw are configured such that when the set screw is rotationally inserted into the receiver, the set screw and receiver provide 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 the receiver, and a gradual decrease in distal compressive force applied to the length of the flexible synthetic strand extending between the intermediate and distal portions of the receiver and the set screw.

Yet another embodiment provides an internal structure 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 centered about the longitudinal axis. The internal structure includes a flexible synthetic strand having a first end and a second opposing end tensioned between a first fixation portion in the first bone tunnel and a second fixation portion in the second bone tunnel, the first fixation portion including a fixation anchor and a threaded set screw. The fixation anchor includes: (1) a head having a proximal side and a distal side, the distal side abutting a first surface of the first bone portion about a first end of the first bone tunnel; (2) a longitudinal shank protruding distally from the head, the shank having a proximal portion, a distal portion, and an axial bore extending therethrough, the shank being 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 having a length approximating the length of the first bone tunnel, and when the shank is inserted into the first bone tunnel, the distal portion of the shank extends to the second end of the first bone tunnel adjacent the second surface of the first bone portion, and the shank provides a bone tunnel protective sleeve.

Additional objects, advantages, and novel features of the present technology will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from the practice of the present technology.

Non-limiting and non-exhaustive embodiments of the present invention, including preferred embodiments, are described with reference to the following figures, in which like reference numerals refer to like parts throughout the various views unless otherwise specified. Exemplary embodiments of the present invention are shown in the drawings.

FIG. 1 is a right side view of a human ankle joint. FIG. 1 is a front view of a human ankle joint. FIG. 1 is a posterior view of a human ankle joint. FIG. 13 is a top view of one embodiment of a button-like suture turn anchor. FIG. 13 is a side view of one embodiment of a headless threaded suture turn anchor. FIG. 1 illustrates a perspective view of one embodiment of a multiaxial suture turn anchor. FIG. 1 illustrates a perspective view of one embodiment of a multiaxial suture turn anchor. FIG. 13 is a front view of one embodiment of a multiaxial suture turn anchor. FIG. 1 is a side view of one embodiment of a multiaxial suture turn anchor. FIG. 13 is a rear view of one embodiment of a multiaxial suture turn anchor. FIG. 1 is a side view of one embodiment of a multiaxial suture turn anchor. FIG. 1 illustrates a cross-sectional view of one embodiment of a multiaxial suture turn anchor. FIG. 1 is a side view of one embodiment of a suture fixation anchor. FIG. 1 is a front view of one embodiment of a suture fixation anchor. 1 is a cross-sectional view of one embodiment of a suture fixation anchor. FIG. 1 illustrates a perspective view of one embodiment of a suture fixation anchor. FIG. 1 illustrates a perspective view of one embodiment of a suture fixation anchor. FIG. 1 is a front view of one embodiment of a suture fixation anchor. FIG. 13 is a rear view of one embodiment of a suture fixation anchor. 20 is a cross-sectional view of a receiver of the suture fixation configuration of the suture fixation anchor of FIGS. 13-19. FIG. 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 , with the screw removed. FIG. 22 is a cross-sectional view of the set screw and receiver of FIG. 21, with the screw removed. FIG. 13 is a perspective view of one embodiment of a threaded suture fixation anchor having a countersunk head. FIG. 1 is a perspective view of one embodiment of a button-type suture fixation anchor having a countersunk head. FIG. 1 illustrates a perspective view of one embodiment of a polyaxial suture fixation anchor. FIG. 1 illustrates a perspective view of one embodiment of a polyaxial suture fixation anchor. FIG. 1 illustrates a side view of one embodiment of a multiaxial suture fixation anchor. FIG. 1 illustrates a cross-sectional view of one embodiment of a multiaxial suture fixation anchor. FIG. 20 is an exploded view of one embodiment of a counter-torque anchor driving instrument in use with the suture locking anchor of FIGS. 1A-1C show partial cross-sectional views through the sacrum parallel to the anatomical transverse plane of the pelvis and illustrating steps of a surgical sequence for reinforcing a sacroiliac fracture joint via a blind hole bone tunnel using an embodiment of the disclosed instrumentation. 1A-1C show partial cross-sectional views through the sacrum parallel to the anatomical transverse plane of the pelvis and illustrating steps of a surgical sequence for reinforcing a sacroiliac fracture joint via a blind hole bone tunnel using an embodiment of the disclosed instrumentation. 1A-1C show partial cross-sectional views through the sacrum parallel to the anatomical transverse plane of the pelvis and illustrating steps of a surgical sequence for reinforcing a sacroiliac fracture joint via a blind hole bone tunnel using an embodiment of the disclosed instrumentation. FIG. 34 provides a flow chart detailing the surgical sequence illustrated by FIGS. 31-33. FIG. 1 is a side view of one embodiment of a ligament attachment fastening structure for the anterior inferior tibiofibular ligament (AITFL) using an embodiment of the disclosed device. 36 provides a flow chart illustrating an exemplary method of operation for forming the ligamentous joint fastening structure of FIG. 35. 1 is a side view of another embodiment of a ligament syndesmosis fastening structure for AITFL using an embodiment of the disclosed device and incorporating a bone plate. 36 provides an illustration of the ligament attachment fastening structure of FIG. 35, each showing progressively longer anchor sleeves that reduce the free range of the suture extending between the sleeves. 36 provides an illustration of the ligament attachment fastening structure of FIG. 35, each showing progressively longer anchor sleeves that reduce the free range of the suture extending between the sleeves. 36 provides an illustration of the ligament attachment fastening structure of FIG. 35, each showing progressively longer anchor sleeves that reduce the free range of the suture extending between the sleeves. FIG. 1 is a lateral view of a human ankle with a fibular shaft fracture. 42A-42D illustrate steps of a surgical sequence for repair of a combined fibular fracture and reinforcement of the syndesmotic joint between the tibia and fibula, as shown in FIG. 41, using an embodiment of the disclosed instrumentation. 42A-42D illustrate steps of a surgical sequence for repair of a combined fibular fracture and reinforcement of the syndesmotic joint between the tibia and fibula, as shown in FIG. 41, using an embodiment of the disclosed instrumentation. 42A-42D illustrate steps of a surgical sequence for repair of a combined fibular fracture and reinforcement of the syndesmotic joint between the tibia and fibula, as shown in FIG. 41, using an embodiment of the disclosed instrumentation. 42A-42D illustrate steps of a surgical sequence for repair of a combined fibular fracture and reinforcement of the syndesmotic joint between the tibia and fibula, as shown in FIG. 41, using an embodiment of the disclosed instrumentation. 42A-42D illustrate steps of a surgical sequence for repair of a combined fibular fracture and reinforcement of the syndesmotic joint between the tibia and fibula, as shown in FIG. 41, using an embodiment of the disclosed instrumentation. 42A-42D illustrate steps of a surgical sequence for repair of a combined fibular fracture and reinforcement of the syndesmotic joint between the tibia and fibula, as shown in FIG. 41, using an embodiment of the disclosed instrumentation. 42A-42D illustrate steps of a surgical sequence for repair of a combined fibular fracture and reinforcement of the syndesmotic joint between the tibia and fibula, as shown in FIG. 41, using an embodiment of the disclosed instrumentation. FIG. 49 provides a flow chart detailing the surgical sequence illustrated by FIGS. 42-48. 49A-49C show alternative steps in a surgical sequence for forming a combined repair and reinforcement structure similar to that shown in FIG. 49A-49C show alternative steps in a surgical sequence for forming a combined repair and reinforcement structure similar to that shown in FIG. 49A-49C show alternative steps in a surgical sequence for forming a combined repair and reinforcement structure similar to that shown in FIG. 49A-49C show alternative steps in a surgical sequence for forming a combined repair and reinforcement structure similar to that shown in FIG. FIG. 54 provides a flow chart detailing the surgical sequence illustrated by FIGS. 50-53.

DETAILED DESCRIPTION The embodiments are described more completely below in sufficient detail to enable those skilled in the art to practice the systems and methods. However, the embodiments may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Thus, the following detailed description should not be construed 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 intra-articular ligament reinforcement and/or fracture repair constructed via a number of suture turn anchors, suture fixation anchors, anchor fixation drivers, bone protection sleeves, and surgical methods using the instruments and devices described herein.

The disclosed devices and/or structures may be used in combination with and/or may utilize, for example, a suture, suture tape, cable, or another suitable flexible synthetic strand (hereinafter, "flexible strand," "flexible synthetic strand," or "suture").

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

The suture turn anchor may be used, for example, when a suture from another part of a reinforcement procedure needs to be secured and tensioned using an approach from one side of the bone. The suture may have a first end secured to another fixed structure and a second free end. The second end may be threaded back through the suture turn anchor so that pulling on the second end tensions the reinforcement structure. The suture turn anchor may also be used to provide two ends or loops of suture that can be tensioned without sliding through the implant.

5 shows another embodiment of a suture turn anchor 270 in the form of a headless screw, including a shank 274 having an external helical thread 275. The shank 274 includes a distal first side hole 278, an axial hole 282 opening at the proximal end of the shank 274, a second side hole 284, and a relief slot 286. From the proximal end, the suture is threaded through the axial hole 282, exits one of the openings of the second side hole 284, passes through the first side hole 278, enters another of the openings of the second side hole 284, and exits the axial hole 282, where the suture is threaded into the proximal portion of the shank. A relief slot 286 may connect the openings of the first and second side holes 278, 284 on each side of the shank 274. The relief groove 286 allows the suture to pass from the axial bore 282 to the first transverse bore 278 while protruding slightly or not at all from the outer wall of the shank 274, protecting the suture from abrasion and allowing the suture to slide more easily while it is threaded and tensioned. A driver can be received in the axial bore 282 to drive the screw into the bone.

6-12 show an example of a polyaxial suture turn anchor 920. In this embodiment, the anchor 920 is a two-piece anchor having a separate washer 922 and shank 924. The shank 924 extends from a proximal end at the washer 922 to a distal end spaced from the washer 922 and includes one or more side holes through which a suture or flexible synthetic strand may be threaded. In this embodiment, the shank 924 includes a first side hole 938 that forms opposing openings on either side of the shank 924 through which the suture is threaded to provide a turn of the suture. 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 hole 942 that extends from an opening at its distal end toward its proximal end. The second side hole 944 extends through the shank 924, forming opposing openings on either side of the shank 924, and is distally offset from the first side hole. The second side hole 944 communicates with the axial hole 942.

The suture is threaded from the distal end through the axial bore 942, out one of the openings of the second side bore 944, through the first side bore 938, through the other opening of the second side bore 944, and out the axial bore 942 so that the suture is threaded into the distal portion of the shank 924. The anchor shank 924 may further include a relief groove 946 connecting the openings of the first and second side bores 938, 944 on each side of the shank 924. The relief groove allows the suture to pass from the axial bore 942 to the first side bore 938 while protruding little or not at all from the shank side, protecting the suture from abrasion and allowing the suture to be threaded and tensioned while sliding more easily.

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

Suture Anchoring Anchor Figures 13-30 show examples of suture anchoring anchors. Figures 13-19 show several views of a suture anchoring anchor 300 having a button-like head 302 and a stepped cylindrical shank 304 that projects outwardly from a distal side of the head 302 and defines a longitudinal axis 306. An axial bore 308 extends through the anchor 300. A proximal portion 310 of the shank has a larger diameter than a distal portion 312 of the shank 304. The proximal portion 310 includes internal threads 314 configured to receive the external threads 334 of a set screw 316 to secure a suture within the axial bore 308.

In use, one or more sutures 318, or other flexible synthetic strands, are threaded through the axial bore 308, tensioned, and then secured in place by inserting the set screw 316 to create an interference engagement between the sutures 318, the threads 334 of the set screw 316, and the threads 314 of the proximal portion 310 of the shank 304.

13-19, the head 302 is mounted non-perpendicular 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 further includes supplemental suture holes 320, 322, 324 extending proximally to distally through the head 302 to allow additional sutures to be threaded through the head 302. Relief channels 321, 323, 325 are provided on the distal surface of the head 302 and communicate with the supplemental suture holes 320, 322, 324 to provide relief for additional sutures between the head 302 and the underlying bone.

As shown in FIGS. 13-19, the head 302 is generally oval shaped 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 cuts from the suture.

Traditional button fixation anchors seat on the outside of the bone at the end of the bone tunnel and are secured by a suture knot tied on the surface of the button, with the knot positioned to irritate the surrounding soft tissue. Over time, the sutures tend to erode the bone at the exit of the bone tunnel, causing the button to sink or recess into the bone. Clinicians have documented migration of the button into bone up to 10mm. As the bone deteriorates and the sutures loosen, the button also generates a level of back and forth translational motion on the surface of the bone, which irritates both the bone and the surrounding tissue.

Embodiments of the suture-securing anchor 300 avoid these complications. The shank 304 extends into a tightly fitted bone tunnel, where the shank 304 is press-fit into the bone cortex or hard outer shell. This increased amount of surface area between the shank and bone cortex, as well as the protective sheath that the shank 304 and head 302 provide for the suture 318 at the bone surface, and the knotless locking mechanism, secure the implant and help prevent the head 302 from cutting or sinking into the bone tunnel, resulting in a more stable, longer-lasting reinforced structure. The excess suture length 318 can be completely trimmed, and the resulting suture is flush with the anchor head 302 and the secured set screw 316, further preventing tissue irritation.

20-23 show details of the suture fixation structure of the example of FIGS. 13-19. FIG. 20 provides a close-up view of the internal structure of the proximal portion 310 of the shank 304, and FIG. 21 provides a cross-sectional view of the proximal portion 310 of the shank 304 receiving the 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 threads 332 and the set screw threads 334 are rounded knuckle threads. Additionally, the receiver 330/receiver threads 332 and the set screw 316/set screw threads 334 feature multiple distinct taper angles transitioning from proximal to distal, providing a gradual grip and release of the 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 the set screw 316 and receiver 330 without knuckle threading to better illustrate the gradual transition of their tapers. The set screw 316 is cylindrical at a proximal portion 350, has a relatively small angular taper over its mid-portion 352, and has a relatively large angular taper over its distal portion 354 terminating in a rounded tip 364. The receiver 330 has a relatively large angular taper at a proximal portion 356, has a relatively small angular taper over its mid-portion 358, and is cylindrical at its distal portion 360. When the set screw 316 and receiver 330 are coupled, they provide progressively less clearance between them from the proximal end of the anchor 300 to their mid-portion, and progressively more clearance between them from their mid-portion distally to the end of the set screw 316.

This opposing tapered configuration of the set screw 316 and receiver 330 incorporates the principle of a Morse taper for interlocking components. The opposing conical shapes of the set screw 316 and receiver 330 closely match or approximate in taper angle at the intermediate portions 352, 358, but the opposing shapes of the set screw 316 and receiver 330 differ in taper angle at their proximal portions 350, 356 and their distal portions 354, 360. This arrangement results in the respective surfaces of the set screw 316 and receiver 330 achieving an interference fit around the suture 318 across the intermediate portions 352, 358 of the set screw 316 and receiver 330, with a gradual transition proximally leading to the interference fit and a gradual transition distally leading away from the interference fit. This gradual transition of compressive force applied to the suture 318 disposed between the set screw 316 and the receiver 330 provides improved suture anchorage/fixation strength while simultaneously reducing the risk of severing the suture 318 that would occur with a greater transition of compressive force.

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

20-23, the set screw 316 may be driven such that the beginning of its intermediate portion 352 is located distal to the beginning of the receiver intermediate portion 358 and the end of the set screw intermediate portion 352 is located proximal to the end of the receiver intermediate portion 358, as shown in FIG. 23. This arrangement results in five clearance zones 340, 342, 344, 346, and 348 for further progressive progression of gripping and release of the suture 318. Any number of taper angle steps may be provided on the set screw 316 and receiver 330, and any arrangement of overlap or radius blend may be provided to create any number of progressive clearance steps, transitioning from proximal to distal, from no grip on the suture, to maximum grip, to no grip, protecting the suture through a progressive increase and decrease in the stress applied to the suture 318.

23, the first zone 340 provides maximum clearance proximally and the clearance decreases distally at the angular difference between the relatively large angle of the cylindrical proximal portion 350 of the set screw 316 and the proximal portion 356 of the receiver 330. The clearance of the second zone 342 decreases distally at the angular difference between the relatively small angle of the cylindrical proximal portion 350 of the set screw 316 and the intermediate portion 358 of the receiver 330. The third zone 344 provides minimum clearance and corresponds to where the intermediate portions 352, 358 of the set screw 316 and the receiver 330 coincide. The clearance of the fourth zone 346 increases distally at the angular difference between the relatively small angle of the intermediate portion 358 of the receiver 330 and the relatively large angle of the distal portion 354 of the set screw 316. The fifth zone 348 provides the greatest clearance distally, and the clearance increases distally with the angular difference between the relatively large angle of the distal portion 354 of the set screw 316 and the cylindrical portion 360 of the receiver 330.

In the illustrative example of FIGS. 20-23, the taper of the set screw 316 is cylindrical at the first proximal portion 350, 10 degrees per side at the second intermediate portion 352, and 20 degrees per side at the distal portion 354. The taper of the receiver 330 is 20 degrees per side at the first proximal portion 356, 10 degrees per side at the second intermediate portion 358, and cylindrical at the third distal portion 360. The resulting clearance angle tapers, corresponding to the five zones 340, 342, 344, 346, 348 shown in FIG. 23, are 20 degrees, 10 degrees, 0 degrees, 10 degrees, and 20 degrees from proximal to distal. In this embodiment, the proximal ends 361, 363 of the receiver 330 and set screw 316 are chamfered and the distal end 364 of the set screw 316 is rounded to further eliminate any sharp edges, further smoothing the suture path and providing easy actuation of the screw.

20-23 feature opposing tapers of the set screw 316 and receiver 330, it will be appreciated that the present invention contemplates any suitable taper configuration that provides a gradual increase and decrease in the compressive force applied to the interference fit of the suture 318 between the set screw 316 and receiver 330 from proximal to distal. For example, the set screw 316 may be completely cylindrical throughout its proximal, intermediate, and distal portions while maintaining the above-described configuration of the receiver 330. In another example, the proximal, intermediate, and distal portions 350, 352, 354 of the set screw 316 may be angled to form an egg-like or football shape, while the proximal, intermediate, and distal portions 356, 358, 360 of the receiver 330 may remain cylindrical.

20-23 provides both a knotless and reversible mechanism for securing the suture 318 to the fixation anchor 300. The fixation configuration provides knotless fixation because the interference fit between the suture 318, the set screw 316, and the receiver 330 provides the necessary compressive force to secure the suture 318 under tension to the anchor 300, thereby reducing the probability of bone and/or tissue wear and/or deterioration often caused by knotted fixation. Furthermore, because the fixation mechanism protects the integrity of the suture through the gradual increase and decrease in stress applied to the suture 318, as described above, the knotless fixation is precisely reversible in that the set screw 316 can be rotated and inserted to secure the suture 318 to the anchor 300 without damaging the suture 318 and/or compromising its structural integrity. As a result, the surgeon may secure and release the suture 318 relative to the anchor 300 multiple times to achieve optimal fixation while maintaining confidence in the quality of the final knotless fixation.

24-25 show additional examples of suture locking anchors incorporating the tapered, knuckle-threaded suture locking devices of FIGS. 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 throughbore 374, and a tapered threaded receiver 376 for receiving a set screw 316 as shown in FIG. 21. FIG. 25 shows a suture locking anchor 394 in the form of a button with a proximal head 387 operable to seat in a spherical countersink in a bone plate. The anchor 394 includes an internal driver mechanism 396, and an axial bore 390, and a tapered threaded receiver 392 for receiving a set screw similar to that shown in FIG. 25. Each of the proximal heads 371, 387 of the anchors 370, 394, respectively, are countersunk so that they are configured to seat within and lie flush with a surface of a bone plate placed and secured to either the tibia 102 or fibula 104 (FIGS. 1-3).

26-29 show an example of a polyaxial suture fixation anchor 1440 similar to the anchor 300 of FIG. 16. However, the example anchor of FIGS. 26-29 is a two-piece anchor having a separate washer 1442 and shank 1444. The washer has a hole 1445 formed therethrough and a spherical seat 1448 formed adjacent the hole. The shank 1444 has a head 1450 with a spherical seat 1452 on its underside adjacent the shank 1444. The spherical seats 1448 and 1452 engage to allow the washer 1442 to assume a range of angles relative to the shank such that when the shank 1444 is inserted and advanced into a bone tunnel and the washer abuts against the bone surface, the washer may angle to match the angle between the bone tunnel and the bone surface. The adjustable polyaxial relationship between the shank 1444 and the washer 1442 allows the washer 1442 to be positioned low profile and close to the bone.

FIG. 30 illustrates a counter torque instrument 960 having a hollow shaft 962 and an anchor engaging end 964. The counter torque instrument 960 may be used to suturelessly lock a suture via an interference fit between a set screw, such as set screw 969, and a number of suitable anchors, such as, for example, anchors 300, 370, 394, and 1440 described above. Focusing on anchor 1440 for illustrative purposes, the anchor engaging end 964 of the counter torque instrument 960 includes spaced apart prongs 966. The prongs 966 are engageable with corresponding grooves 1454 formed in the head 1450 of the shank 1444 of the anchor 1440. This engagement provides a counter torque force that holds the shank 1444 stationary and prevents the shank 1444 from rotating when the set screw 969 is driven or tightened into the anchor 1440 using an appropriate set screw driver inserted through the hollow shaft 962. Thus, the surgeon may drive the set screw 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, allowing the washer 1442 to be placed flush with the bone, as previously described. This ability to resist the torsional forces generated by the driver and set screw 969 on the washer 1442 and/or the shank 1444 of the anchor 1440 is satisfying to the surgeon and results in more effective anchor placement and locking.

Intra-Articular Constructs and Surgical Sequences FIGS. 31-54 show several methods, according to examples of the present invention, that may be used to internally stabilize or strengthen ligaments across a bone joint and/or stabilize bone segments across a fracture.

FIGS. 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, into which a first anchor fits and a second anchor follows the first anchor in the blind hole tunnel. More specifically, in one embodiment, the exemplary instrument is used to repair the sacroiliac joint 2113 and stabilize the pelvis after an anterior-posterior compression fracture. FIG. 34 provides a flow chart showing an exemplary method 1500 of reinforcing the sacroiliac joint 2113 according to the steps shown in FIGS. 31-33.

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 countersunk 254 is formed on the surface of the ilium 2107 at the entrance of the tunnel 250 (FIG. 34, 1504). A first anchor 256 is inserted through the tunnel 250 into the sacrum 2102 where it secures a flexible strand such as a suture 258 (FIG. 34, 1506). The flexible strand 258 extends from the posterior end of the first anchor 256, through the tunnel 250, and out of the ilium 2107.

Referring to FIG. 32, the flexible strand 258 is placed through a second anchor 260 that seats on the ilium 2107 (FIG. 34, 1506-1508). The second anchor 260 includes a tubular portion 262 that extends into the tunnel countersink 254 and a washer portion 264 that rests on the ilium surface. In the example of FIGS. 31-33, the tubular portion 262 and the washer portion 264 are separate pieces that engage at a cylindrical seat 266, allowing them to articulate relative to one another and adaptively align with the bone surface and the tunnel 250.

To tension the portion of the suture 258 extending between the anchors 256, 260 (FIG. 34, 1510), the ends of the 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. The suture 258 can then be locked against the second anchor to maintain the tightening (FIG. 34, 1512). To lock, a locking set screw 270 can be advanced through the central cannula of the tensioning tool and threaded into the internal threads 272 formed in the second anchor 260, thereby locking the suture 258 against the second anchor 260 by the interference fit between the screw 270 and the internal threads 272 of the anchor 260. The tensioner may then be removed and any excess length of suture 258 may be trimmed off so that suture 258 is 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 the prior art iliac-sacral screws. The malleable structure shown in FIG. 33 is advantageous in that it provides controlled tightening of the unstable joint after placement of the anchors. With the tensioners still attached, the joint is tested and the tension adjusted to the desired stability. The tension of the joint may be adjusted to any desired value prior to securing the suture 258 to the second anchor 260. The locking mechanism is knotless and reversible, allowing for 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, making it less susceptible to failure than rigid implants that may experience fatigue failure.

33 may be applied in any desired location relative to the joint. The location of the structure may be more anterior or posterior, or more superior or inferior. The first anchor 256 may be set deeper into the sacrum. The first anchor 256 may be secured to the cortical bone of the sacrum opposite the unstable sacroiliac joint, with the suture 258 spanning the sacrum. Multiple structures may be applied to achieve a desired level of stability. Multiple structures may be spaced superior to posterior and/or anterior to posterior. Additionally, although FIGS. 31-34 refer to augmenting the sacroiliac joint 2113 to stabilize the pelvis after anterior-posterior compression fractures, similar methods and instruments may be used as needed to stabilize various bone joints within the body.

FIG. 35 shows an exemplary device used to reinforce a ligament that runs across a joint between two bones. More specifically, and in one embodiment, FIG. 35 shows a ligament attachment tightening structure 1650 for the anterior inferior tibiofibular ligament (AITFL) 110, and FIG. 36 provides a flow chart illustrating an exemplary method 1600 of strengthening the AITFL 110 shown in FIG. 35.

35, first, a bone tunnel 1652 is formed through the fibula 104 and a second coaxial adjacent tunnel 1654 is formed in the tibia 102 (FIG. 36, 1602). A first suture wrap anchor 1656 is inserted into the fibula 104 through the first tunnel 1652 (FIG. 36, 1604). The suture wrap anchor may be, for example, the polyaxial suture wrap anchor 920 described above in connection with FIGS. 6-12. A second suture fixation anchor 1658 is inserted into the tibia 102 through the second tunnel 1654 (FIG. 36, 1606). The suture fixation anchor may include, for example, the suture fixation embodiment described above in connection with FIGS. 13-29.

A flexible strand such as suture 1660 may be threaded from the right through the second suture fixation anchor 1658, back through the first suture wrap anchor 1656, and back through the first suture fixation anchor 1658 (FIG. 36, 1608) so that both ends of the suture 1660 extend from the second suture fixation anchor 1658, which is seated in the tibia 102.

The second anchor 1658 includes a tubular portion 1662 that extends into the tunnel 1654 and a washer portion 1664 that rests on the tibia surface. In the example of FIG. 35, the tubular portion 1662 and the washer portion 1664 are separate pieces that engage in a cylindrical seat, allowing them to articulate relative to one another to conformably align with the surfaces of the tunnel 1654 and the tibia 102, respectively.

Using a suitable tensioning device, the ends of the suture 1660 may be pulled to tension the suture 1660 extending between the first anchor 1656 and the second anchor 1658 (FIG. 36, 1610). As a result, the syndesmotic joint is tightened and the ligament 110 is strengthened, as shown in FIG. 35. The suture 1660 may then be secured to the second suture securing anchor 1658 to maintain the tightening (FIG. 36, 1612). The tensioning device may then be removed and any excess length of the suture 1660 may be trimmed off, leaving the suture 1660 flush with the anchor 1658 (FIG. 36, 1614).

As with the sacroiliac joint repair of Figs. 31-34, the ligament reinforcement structure 1650 described in connection with Figs. 35-36 provides continuous, uninterrupted strands from one anchor to another along the direction of the natural ligaments and controlled tightening of the unstable joint after placement of the anchors. The joint is tested with the tensioner attached and the tension adjusted to the desired stability. The tension is adjusted prior to fixation and can be readjusted as necessary and/or desired. The structure places a continuous, uninterrupted flexible member (e.g., suture 1660) across the joint, making it less susceptible to failure than rigid implants that may experience fatigue failure.

The structure 1650 of FIG. 35 may be applied in any desired location relative to the joint/ligament. The location of the structure may be more anterior or posterior (e.g., configured to reinforce the PITFL 112), or more superior or inferior. Multiple structures may be applied to achieve a desired level of stability. Multiple structures may be spaced apart, superior to inferior, and/or anterior to posterior. Additionally, although FIGS. 35-36 refer to reinforcing the AITFL 110, similar methods and devices may be used to reinforce any ligament in the body, as desired. As shown in FIG. 37, the exemplary structure may be used with a bone plate 1670.

35, the tubular portion 1662 of the anchor 1658 functions as a suture sleeve that extends toward the end of the second bone tunnel 1654 and the medial surface of the tibia 102. Similarly, the tubular portion 1666 of the first anchor 1656 functions as a suture sleeve that extends toward the end of the bone tunnel 1652 and the medial surface of the fibula 104. The tubular portions/sheaths 1662, 1666 provide protection for the bone tunnel and limit lateral movement of the suture 1660, or wiping of the suture, within the space between the sleeves 1662, 1666. If the sleeves 1662 and 1666 extend to the end of the bone tunnel 1654/surface of the tibia 102 and the end of the bone tunnel 1652/surface of the fibula 104, respectively, the suture 1660 is flexible only over the full length of the natural ligament, and lateral movement or wiping of the suture is limited to the length of the full length of the natural ligament across the joint between the bones (e.g., 1-2 mm). Because wiping of the suture over time wears the bone in and around the bone tunnel edges, using an anchor featuring a hollow shaft/sheath to house the suture, in turn, reduces the wear of the bone caused by the suture. The further the tubular portions/sleeves 1662, 1666 extend toward the other bone, the less likely such wiping of the suture and the resulting wear may occur.

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

FIGS. 41-47 show steps of a method 1700 involving repair of a combined fibular fracture and reinforcement of the syndesmotic joint with exemplary instruments and devices of the present invention, and FIG. 49 provides a flow chart illustrating the method 1700, which is shown in detail in FIGS. 41-52. By way of background, FIG. 41 shows a lateral view of a human ankle 100 showing a fracture 116 of the fibular shaft 104.

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

43-44, a first tunnel 127 is formed through the fibula 104 and tibia 102 to receive a stabilizing element across the syndesmotic joint to stabilize the joint, particularly the interosseous ligament 114 (FIG. 49, 1704). The first tunnel 127 is preferably formed adjacent to the edge of the 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 fibula eminence 125 at a fixed height and through the center of gravity of the fibula 104 and tibia 102. In this embodiment, the first tunnel 127 is formed adjacent to the anterior end of the plate 120. The first tunnel 127 may be spaced more or less from the plate and/or may be located posterior to the plate depending on the surgeon's preference and the location of the plate. In the example of Figures 41-52, the plate 120 is positioned posteriorly to accommodate the preferred path of the first tunnel 127 through the bone.

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

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

Next, as shown in FIG. 46, the suture threader 130 is passed through the plate 120, the auxiliary tunnel 126, and the first tunnel 127, thereby exiting through the plate 120 and the tibia 102 (FIG. 49, 1708). Next, the flexible synthetic strand 132 is engaged with the threader 130 (FIG. 49, 1710). As described above, the flexible synthetic strand can be a high strength suture, suture tape, cable, or another suitable flexible synthetic strand.

Referring to FIG. 47, the threader 130 is withdrawn through the bones 102, 104 and the plate 120, advancing the flexible strand 132 through the bone and the plate 120 (FIG. 49, 1712). The threader 130, or another threader with a flexible strand engaged thereto, is then passed through the first tunnel 127, exiting one end from the fibula 104 and the other end from the tibia 102 (FIG. 49, 1714).

Figure 48 shows that the threader 130 is pulled through the bones 102, 104, advancing the flexible strand 132 through the first tunnel 127 (Figure 49, 1716). The flexible strand 132 is now looped around the anterior end of the plate 120, with the two legs of the flexible strand 132 extending across the syndesmotic joint between the tibia 102 and the fibula 104. The ends of the flexible strand 132 can then be pulled, clamping the syndesmotic joint and tensioning it appropriately (Figure 49, 1718). Tension can be applied manually by pulling directly on the ends of the flexible strand. Alternatively, a tensioning device can be used to apply and/or indicate tension. The flexible strands 132 may be secured, for example, by tying the ends on button anchors, inserting an interference screw into the first tunnel, securing the ends to the tibial surface adjacent the exit hole of the first tunnel 127 using one or more staples, or securing the flexible strands with other knotless anchors.

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

Referring to FIG. 51, the hook 140 is pulled through the bones 102, 104, with the bend 138 passing through the plate 120, the auxiliary tunnel 126, and the first tunnel 127, and exiting the tibia 102 (FIG. 54, 1808). A threader, such as threader 130, is inserted through the first tunnel (FIG. 54, 1810), and the free end of the flexible strand 132 engages the threader (FIG. 54, 1812).

FIG. 52 shows the threader 130 being pulled through the bone to thread the free end of the flexible strand 132 through the first tunnel 127 (FIG. 54, 1814) before the free end of the flexible strand 132 is passed through the bend 138 (FIG. 54, 1816).

53, the free end of the flexible strand 132 is tensioned to transition the bend 138 down the first tunnel 127 and form a girth hitch 144 (FIG. 54, 1818) around the anterior end of the plate 120 and the portion of the bone 142 between the first tunnel 127 and the auxiliary tunnel 126. If necessary, a push rod, forceps, or other instrument may be used to push the bend 138 and aid in its movement down the tunnel 127 as the free end is tensioned. Forming the illustrated girth hitch 144 may improve the direction of the flexible strand 132 through the bone and reduce the tendency of the flexible strand to press against the edges of the tunnel. The flexible strand 132 may be tensioned (FIG. 54, 1820) and secured (FIG. 54, 1822) as described above in connection with FIG. 48.

The ligamentous reinforcement sequence according to the present example achieves a very low profile, and the flexible strands wrap around the plate edges to secure the bone plate, providing flexible reinforcement without rigid hardware spanning the joint. These advantages are achieved while avoiding x-ray shadowing of the joint interface. Reinforcements according to the present example may accommodate a variety of plate positions, such as more anterior or posterior, since the tunnels may be aligned with or offset from either the anterior or posterior edges of the plate. Reinforcements according to the present example are easily modifiable, since the flexible strands are simply cut and the fixation removed from the tibial side of the structure. In particular, the bone plate may be fixed to the fibula as shown, and fixed to the tibia as needed and/or appropriate.

Although the above embodiments have been described in language specific to certain structures, elements, configurations, and methodological steps, it should be understood that the technology defined in the appended claims is not necessarily limited to the particular structures, elements, configurations, and/or steps described. Rather, certain aspects and steps are described as forms of implementing the claimed technology. Because many embodiments of the technology may be made without departing from the spirit and scope of the invention, the invention resides in the following appended claims.

Claims (7)

1. An apparatus 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 centered about the longitudinal axis, comprising:
a first fixation portion disposed within the first bone tunnel;
a second fixation portion disposed in the second bone tunnel; and
a flexible synthetic strand having first and second opposed ends tensioned between the first anchor portion and the second anchor portion;
the first fixation portion includes a fixation anchor and a threaded set screw;
The fixation anchor comprises:
a head having a proximal side and a distal side, the distal side abutting a first surface of the first bone portion about a first end of the first bone tunnel;
a longitudinal shank protruding distally from the head, the longitudinal shank having a proximal portion, a distal portion, and an axial bore extending therethrough, the longitudinal shank being inserted into the first bone tunnel from the first end of the first bone tunnel toward a second end of the first bone tunnel adjacent the joint, the longitudinal shank having a length approximating a 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 second end of the first bone tunnel adjacent a second surface of the first bone portion, the longitudinal shank providing a bone tunnel protective sleeve ;
a threaded receiver formed in the proximal portion of the longitudinal shank;
the first and second opposing ends of the flexible synthetic strand are secured to the fixation anchor via the threaded set screw that is rotatably inserted into the threaded receiver, providing a continuous, uninterrupted length of the flexible synthetic strand extending inwardly across the joint between the first and second fixation portions . 2. The device of claim 1 , wherein the second fixation portion includes a turn-over anchor including a second longitudinal shank having a second axial bore formed therein and a turn-over configuration in communication with the second axial bore, the second longitudinal shank being inserted into the second bone tunnel;
the first opposing end of the flexible synthetic strand passes through the threaded receiver into the fixation anchor, through the bone tunnel protection sleeve, across the joint between the first and second bone portions, through the second axial bore into the turn-around anchor, around the turn-around configuration, through the second axial bore, out the turn-around anchor, through the bone tunnel protection sleeve to re-enter the fixation anchor, and through the threaded receiver out the fixation anchor;
The device, wherein the flexible synthetic strand is tensioned between the fixed anchor and the turn-over anchor. 2. The apparatus of claim 1,
The second fixation portion includes a turn anchor,
The second bone tunnel is a blind hole tunnel, and the turn-around anchor 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. 3. The device of claim 2 , wherein the turnover anchor further comprises a second head having a proximal side and a distal side, the distal side of the second head adjacent a first surface of the second bone portion about a first end of the second bone tunnel;
the second longitudinal shank protrudes distally from the second head, the second longitudinal shank having a length approximate to a length of the second bone tunnel, when the second longitudinal 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, the second longitudinal shank extends to the second end of the second bone tunnel adjacent a second surface of the second bone portion, and the second longitudinal shank provides a second bone tunnel protective sleeve. 5. The apparatus of claim 4 , wherein the second head of the turnover anchor is aligned on a bone plate to abut the first surface of the second bone portion in the second bone tunnel. The device of claim 1, wherein the head of the fixation anchor is pivotally coupled to the proximal portion of the longitudinal shank, and the head is selectively angled to achieve an anchor angle between a distal face of the head and the longitudinal shank that matches a tunnel angle between the first bone tunnel and a first bone surface. 2. The device of claim 1, wherein the threaded receiver of the fixation anchor includes a proximal portion, an intermediate portion, and a distal portion, and the threaded set screw includes a proximal portion, an intermediate portion, and a distal portion, the threaded set screw configured to rotate and insert into the threaded receiver to achieve a progressively increasing interference fit around the flexible synthetic strand passing between the threaded receiver and the proximal and intermediate portions of the threaded set screw and a progressively decreasing interference fit around the flexible synthetic strand passing between the threaded receiver and the intermediate and distal portions of the threaded set screw, the progressively increasing interference fit and the progressively decreasing interference fit combining to secure the flexible synthetic strand relative to the fixation anchor.

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