Patent Description:
When soft tissue, such as tendons and ligaments, is torn away from the bone, surgery, such as arthroscopic surgical techniques, may be required to repair the tear and reattach the tissue to bone. Typically, a suture is threaded through the torn tissue and through a suture anchor in a tunnel or hole drilled into the bone. The suture can be drawn up and tensioned to approximate the torn tissue against the bone in proper position to heal.

Suture anchors are devices that are typically insertable arthroscopically through a cannula to the repair site and then implanted to anchor the repair suture to bone. That is, the repair suture is passed through the soft tissue and through the suture anchor to reattach the tissue to bone. Such a suture anchor assembly is disclosed in commonly owned <CIT> and <CIT>.

One known tendon repair technique using suture anchors, namely Arthrex's SutureBridge®, disclosed in commonly assigned <CIT>, has a tied medial row constructed with two threaded suture anchors, combined with knotless lateral fixation using two anchors, such as two of Arthrex's PushLock® anchors. The technique enhances footprint compression and promotes tendon healing-to-bone with minimal knot tying. Another known tissue repair technique, namely Arthrex's SpeedBridge®, uses a threaded swivel anchor (such as disclosed in <CIT>) combined with FiberTape® (disclosed in <CIT>) to create a quick and secure bridge construct, as discussed above, with no knots and minimal suture passing steps. <CIT>, <CIT> and <CIT> disclose suture anchors.

Securing suture during surgery using known techniques can sometimes be difficult, if the repair suture is loose and slack remains in the suture or repair construct, particularly after installation of the suture anchor in bone. Accordingly, a need exists for a suture anchor assembly and tissue repair technique that effectively reduces any slack in the suture used for tissue repair.

Accordingly, the present invention may provide a surgical anchor assembly that comprises a fixation device having a proximal end, a distal end, a cannulation extending therethrough, and a first engagement feature at or near the distal end. An implant of the surgical anchor assembly may comprise a first portion connectable to the distal end of the fixation device and a second engagement feature engageable with the first engagement feature, and a second portion configured to capture a flexible strand. A stop mechanism may be configured to prevent rotational movement between the fixation device and the implant in at least one direction when the implant is connected to the fixation device.

In certain embodiments, the first portion of the implant is insertable into the distal end of the fixation device; the first engagement feature is formed in the cannulation of the fixation device, and the second engagement feature is formed on an outer surface of the first portion of the implant; the first and second engagement features facilitate a limited rotational connection between the fixation device and the implant, and the stop mechanism is configured to stop the rotational movement facilitated by the first and second engagement features; the stop mechanism is formed in the cannulation of the fixation device at or near the distal end section; the first and second engagement features each comprises a thread; an end of the thread of the first engagement feature defines the stop mechanism; when the implant and the fixation device are connected with the stop mechanism preventing rotation therebetween, the second portion of the implant remains outside of and extends away from the distal end of the fixation device; the second portion of the implant comprises an eyelet for capturing the flexible strand; an exterior surface of the fixation device comprises an engagement feature for engaging a bone hole; and/or the engagement feature on the exterior surface of the fixation device comprises a thread.

The present invention may also provide a surgical anchor assembly that comprises a fixation device having a proximal end, a distal end, a cannulation extending therethrough, and an exterior surface with a first engagement feature for engaging a bone hole. An implant of the surgical anchor assembly may comprise a first portion connectable to the distal end of the fixation device in a rotationally fixed manner and a second portion configured to capture a flexible strand. A separate piggyback fixation piece may further be connectable to the proximal end of the fixation device to extend a total length of the surgical anchor assembly, where an exterior surface of the piggyback fixation piece comprises a second engagement feature that is complementary to the first engagement feature on the exterior surface of the fixation device for engaging the bone hole.

In certain embodiments, the fixation device and the piggyback fixation piece comprise the same material; the fixation device and the piggyback fixation piece comprise different materials; the piggyback fixation piece has a shorter length than a length of the fixation device; the first and second engagement features each comprises a thread, and the thread of the second engagement feature is alignable with the thread of the first engagement feature; and/or the implant is rotatably connectable to the fixation device in a limited manner, and a stop mechanism is configured to stop the rotational movement in at least one direction resulting in the rotationally fixed connection.

A method of tissue repair, not part of the invention may be using a surgical anchor assembly that may comprise a fixation device having a proximal end, a distal end, a cannulation extending therethrough, and a first engagement feature at or near the distal end, an implant comprising a first portion connectable to the distal end of the fixation device and having a second engagement feature engageable with the first engagement feature, and a second portion, and a flexible strand. The method may comprise the steps of advancing the implant in a bone hole when the flexible strand is captured by the second portion of the implant; advancing the fixation device over the implant to connect the implant to the fixation device, where a stop mechanism prevents rotational movement between the fixation device and the implant in at least one direction; and rotating the fixation device and the implant together in the at least one direction to wrap the flexible strand around at least one of the implant or the fixation device for reducing slack in the flexible strand.

In certain embodiments, the first and second engagement features each comprises a thread, and the step of advancing the fixation device over the implant comprises threadably engaging the fixation device with the implant. In certain embodiments, the method further comprises at least one of the following additional steps: using an inserter to advance the implant in the bone hole and to advance the fixation device, where the inserter is configured to extend through the cannulation of the fixation device, and where an end of the inserter is configured to hold the implant; threading the flexible strand through or around tissue prior to rotating the fixation device and the implant together to reduce the slack in the flexible strand; stacking a piggyback fixation piece on the proximal end of the fixation device prior to rotating the fixation device and the implant together to reduce the slack in the flexible strand; removing portions of the piggyback fixation piece that protrude outside of the bone hole after rotating the fixation device and the implant together to reduce the slack in the flexible strand; forming the bone hole prior to advancing the implant, where the bone hole has a cylindrical profile with a length that is at least a combined length of the fixation device and the implant when the implant is connected to the fixation device; and/or forming the bone hole prior to advancing the implant, where the bone hole has a cylindrical profile with a conically shaped distal end, and where the length of the cylindrical portion of the bone hole is at least a combined length of the fixation device and the implant when the implant is connected to the fixation device.

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing figures:.

Referring to the figures, the present invention generally relates to a suture anchor assembly <NUM> designed to enable reduction of residual slack in the repair suture, tape, or flexible strand during a tissue repair procedure. Suture anchor assembly <NUM> may generally include a cannulated fixation device <NUM> that has an inner engagement feature <NUM>, an implant <NUM> that captures one or more repair flexible strands <NUM> and may be rotatably coupled to the fixation device <NUM>, wherein the implant <NUM> has an outer engagement feature <NUM> corresponding to the inner engagement feature <NUM>, and a stop mechanism <NUM> that is associated with the inner and outer engagement features <NUM> and <NUM>. Stop mechanism <NUM> stops or prevents further rotation and/or other relative movement between the fixation device <NUM> and the implant <NUM> to unify the same such that the unified fixation device <NUM> and implant <NUM> can be rotated together to wind up and reduce or take up any slack or redundancy in the repair suture, tape, or flexible strand during a repair of the tissue, as seen in <FIG>.

Fixation device <NUM> may have a proximal end section <NUM>, a distal end section <NUM>, and a cannulation <NUM> therethrough, with the inner engagement feature <NUM> being disposed in the cannulation <NUM> at the distal end section <NUM>. Fixation device <NUM> has a fixation exterior surface <NUM> configured to engage bone <NUM>, such as via a bone hole or bone socket 99a, 99b, as seen in <FIG>, respectively. Bone socket 99a (<FIG>) is preferably elongated with, for example, a cylindrical shape or profile. A bone socket with such cylindrical profile that extends all the way to the distal end of the bone socket can be formed, for example, with a headed reamer or a second-stage punch. In some embodiments, a blunt punch or a modified flip-cutter drill can be used to make the distal region of the bone socket more spacious, without compromising the structure of the more proximal regions of the bone socket. A different bone socket 99b (<FIG>) is also preferably elongated with, for example, a cylindrical shape or profile, and further having a cone shaped bottom. This type of bone socket can be formed simply with a longer conical punch. The conical bottom of bone socket 99b may also be formed to be more elongate than typical, for example, with a separate conical punch with a more elongate profile. Generally, the length of the cylindrical portions of the bone sockets 99a, 99b are formed to be approximately the same or greater than a combined length of the unified fixation device <NUM> and implant <NUM>, so that the bone socket remains cylindrical at an axial level of the implant <NUM>, before additional advancement is performed as described in greater detail below. Both bone socket arrangements 99a, 99b may better accommodate suture anchor assemblies according to embodiments of the invention. It is noted, however, that suture anchor assemblies according to embodiments of the invention can also be accommodated in more traditionally shaped bone holes or bone sockets, or more generally, bone holes with profiles that differ from those of bone sockets 99a, 99b. Fixation exterior surface <NUM> may comprise, for example, exterior threads or ridges, or be any known anchoring surface, for engaging and anchoring into the bone. Implant <NUM> is preferably rotatably coupled to the distal end section <NUM> of fixation device <NUM>. Implant <NUM> may comprise a body <NUM> that has at least first and second portions <NUM> and <NUM>, where the first portion <NUM> may be configured to be receivable in the distal end section <NUM> of fixation device <NUM> and the second portion <NUM> may be configured to capture at least one flexible strand <NUM>. The second portion <NUM> may include, for example, an eyelet <NUM> or the like capable of capturing the flexible strand <NUM>.

Stop mechanism <NUM> may be any structure that provides a hard stop and prevents further rotation and/or other relative movement between the fixation device <NUM> and the implant <NUM>. And the stop mechanism <NUM> may be incorporated into either the inner engagement member <NUM> of fixation device <NUM> or the outer engagement member <NUM> of the implant <NUM>. In an exemplary embodiment, stop mechanism <NUM> is disposed in the cannulation <NUM> of the fixation device, at the distal end section <NUM>. Here, the inner engagement member <NUM> of the fixation device may be internal threads with a pre-determined limited distance or length L, where the end <NUM> of that predetermined length L forms the stop mechanism <NUM>, as best seen in <FIG>. That is, when implant <NUM> is being coupled to the distal end section <NUM> of fixation device <NUM>, the outer threads <NUM> of the implant <NUM> will engage the inner threads <NUM> of fixation device <NUM>, thereby threadably coupling the same until the implant's outer threads <NUM> reach the end <NUM> of the fixation device's inner threads <NUM>. The end <NUM> of the inner threads <NUM> of the fixation device then prevents further relative movement (e.g., rotation or swiveling) between the implant <NUM> and the fixation device <NUM>, such that the implant <NUM> and fixation device <NUM> form a single unit and can be rotated together (i.e., at the same rate as one another) due to the engagement therebetween. As such, after engagement at the stop mechanism <NUM>, additional rotational advancement or driving of fixation device <NUM>, for example, clockwise into the bone hole will also result in rotational advancement of the implant <NUM> as well, causing the flexible strand <NUM> that is captured in eyelet <NUM> to wrap around the assembly and tighten. Other known engagement features may be used instead, such as bayonet or snap engagement, or the like, with the stop mechanism <NUM> being either incorporated into the engagement between the fixation device <NUM> and the implant <NUM> or separate from that engagement.

<FIG> illustrate another exemplary embodiment of the present invention. Ideally, in a fully implanted configuration, a proximal end of fixation device <NUM> is positioned substantially flush with the surface of the bone, to maximize fixation between the suture anchor assembly <NUM> with the bone, especially cortical bone. In some cases where additional tightening of the flexible strand <NUM> is desired via additional rotation of fixation device <NUM>, suture anchor assembly <NUM> will advance further into the bone and engage less solid regions of the bone, while contact between the distal end of fixation device <NUM> and cortical bone will be reduced. In such situations, a piggyback anchor or fixation piece <NUM> may serve as an extension of the anchor that is attached to or otherwise added to the proximal end of the fixation device <NUM> to essentially lengthen the fixation device <NUM> to ensure that the threads of the suture anchor assembly <NUM> as a whole engage cortical bone for better anchoring of the combined assembly <NUM> in the bone socket. Piggyback fixation piece <NUM> may be similar to the fixation device <NUM>, except with a shorter length. A fixation exterior surface <NUM> of piggyback fixation piece <NUM> may be complementary to that of the fixation device <NUM>, such as exterior threads or ridges. Piggyback fixation piece <NUM> may be cannulated, and either end <NUM> or <NUM> of piggyback fixation piece <NUM> may be stacked on the proximal end section <NUM> of fixation device <NUM>, as seen in <FIG>. In <FIG>, the piggyback fixation piece <NUM> has been placed over an inserter <NUM>, which in turn extends entirely through and out of the distal end <NUM> of the piggyback fixation piece <NUM>. The fixation device <NUM> and the piggyback fixation piece <NUM> may be formed of the same or different materials. Exemplary materials may include polyether ether ketone (PEEK), bioabsorbable material, biocomposite material, metal, and the like.

In some embodiments, the distal end <NUM> of piggyback fixation piece <NUM> may include an engagement feature to axially and/or rotationally lock with the proximal end of fixation device <NUM>, to provide for a more secure fixation between the respective parts. In yet another alternative embodiment of the piggyback anchor, rather than having a piggyback anchor that is fully cannulated and placed over a separate driver or inserter, where the end of the driver or inserter interacts with the cannulation of the fixation device <NUM>, a distal end of the piggyback anchor itself may include a projection configured to be form-fit into the cannulation of the fixation device, for example, with matching hex profiles. Here, a tool recess may instead be formed at the proximal end of the piggyback anchor, so that a tool can be used to effect rotation of the piggyback anchor, while the piggyback anchor effects rotation of both the fixation device and implant via the form-fit with the fixation device.

A method of tissue repair not part of the present invention may comprise the initial steps of installing the implant <NUM> in the prepared bone hole or socket 99a or 99b and then advancing the fixation device <NUM> over the implant <NUM>, such as disclosed in commonly owned <CIT> and <CIT>. The flexible strand <NUM> may be captured by implant <NUM>, such as by threading the flexible strand <NUM> through the eyelet <NUM> of implant <NUM>. To install the implant <NUM> with the captured flexible strand <NUM>, implant <NUM> may be coupled to an operative distal end of a driver or inserter <NUM> and then placed within the prepared bone hole 99a, 99b until the implant <NUM> reaches the desired depth. The driver or inserter <NUM> may be the same as or different from the inserter discussed above with respect to the piggyback fixation piece <NUM>. A rod <NUM> of the inserter <NUM> may be received in the cannulation <NUM> of fixation device <NUM>, and fixation device <NUM> may then be advanced down rod <NUM> to be inserted over the implant <NUM>, such as by holding and turning a handle (not shown) of the driver <NUM>. The rod <NUM> of the driver <NUM> may have an outer profile, for example, a hex profile, that matches an inner profile of cannulation <NUM> of fixation device <NUM>, so that rotation of rod <NUM> also results in rotation of fixation device <NUM>. The inner engagement member <NUM> of the fixation device also engages the outer engagement member <NUM> of implant <NUM>, such as via a threaded engagement, as it advances over the implant <NUM>.

Advancement of the fixation device <NUM> and the relative movement of (e.g., rotation between) the fixation device <NUM> and the implant <NUM> is stopped by stopping mechanism <NUM>, such as by the outer threads <NUM> of the implant <NUM> reaching the end <NUM> of the inner threads <NUM> of fixation device <NUM>. The flexible strand <NUM> may be threaded through or around the damaged tissue. Thereafter, the fixation device <NUM> and the implant <NUM> may be rotated together as a unit to wind the flexible strand <NUM> captured by the implant <NUM>, thereby reducing any slack (<FIG>) in the flexible strand <NUM>.

When rotating the fixation device <NUM> and the implant <NUM> together, the flexible strand <NUM> may be wrapped around a portion of the implant <NUM>, as seen in <FIG>, or around the fixation device <NUM>, as seen in <FIG>, or both. In this manner, the flexible strand <NUM> may be tightened after threading the flexible strand <NUM> through or around the tissue. Furthermore, when utilized, the construction of bone holes 99a, 99b forms wider distal regions of the respective bone holes that provide added room or space for the wrapping of the flexible strand <NUM> around the distal region of the suture anchor assembly. This is in contrast to typical bone holes with more constricted distal regions, where further advancement of the anchor assemblies into those bone holes may be resisted or otherwise restricted after full engagement between the implant <NUM> and the fixation device <NUM>, due to lack of space. Bone hole constructions according to embodiments of the invention can serve to avoid or significantly decrease torsional forces, frictional resistance, and/or other pressures being applied against the flexible strand <NUM>, the implant <NUM>, and/or the distal region of the fixation device <NUM> by the wall of the bone hole, and prevent potential damage to the assembly that would otherwise be caused by such added forces or pressures, as the assembly is further advanced into the bone hole and the wrapping of the flexible strand <NUM> around the suture anchor assembly increases a width of the assembly at its distal end.

In an alternative embodiment, the method, also not being part of the invention may include the step of stacking the piggyback fixation piece <NUM> on the fixation device <NUM> as an extension of the fixation device <NUM> after advancing the fixation device <NUM> over the implant <NUM> in the bone hole. These additional steps may be desirable, for example, when the fixation device <NUM> has been advanced into the bone hole to a point where the distal end of the fixation device <NUM> has already completely engaged the implant <NUM> to the stop mechanism <NUM> and the proximal end of the fixation device is already flush with the surface of the bone, but where there is still laxity in the flexible strand <NUM> (e.g., as seen in <FIG>, prior to attachment of piggyback fixation piece <NUM>). Advancing the suture anchor assembly farther into the bone hole will serve to wrap and wind-up the flexible strand <NUM> around the suture anchor assembly and reduce slack in the flexible strand <NUM>, but will also cause the proximal end of the fixation device <NUM> to advance deeper and be recessed from the surface of the bone, reducing cortical fixation. In such situations, the piggyback fixation piece <NUM> can strengthen and reinforce the fixation between the suture anchor assembly and the bone, where the piggyback fixation piece <NUM> serves to fill in the recess caused by the additional advancement of the fixation device <NUM> into the bone hole.

The rod <NUM> of the inserter <NUM> may be inserted through the cannulation of the piggyback fixation piece <NUM> such that the end of rod <NUM> is exposed or extends away from end <NUM> by a distance D (<FIG>). The distance D is generally equal to the depth of the implant <NUM> in the fixation device's cannulation <NUM>, or in other words, the length of the portion of the fixation device <NUM> that extends proximal to the end <NUM> of the inner thread <NUM>, as seen in <FIG>, so that the exposed end of rod <NUM> can be fully inserted into the fixation device <NUM> with the piggyback fixation piece <NUM> abutting the fixation device <NUM>, while the implant <NUM> is also completely engaged with the fixation device <NUM>. Limiting extension of the end of rod <NUM> to the distance D may be accomplished, for example, via a larger diameter or similar abutment on the inserter <NUM>, or another stop feature between the inserter <NUM> and the piggyback fixation piece <NUM>. In another embodiment, a different inserter tool can be used that is similar to the initial inserter tool used for advancing the fixation device <NUM> to the implant <NUM> at the implant site, where an initial or greatest length of the exposed region of the rod <NUM> is different (typically shorter compared to the initial inserter tool), corresponding to a total sum of the distance D and a length of the piggyback fixation device <NUM>, so that full insertion or mounting of the piggyback fixation piece <NUM> over the rod <NUM> results in a distal extension of the rod <NUM> substantially equaling the distance D. In still other embodiments, an additional stopping feature may not be needed. The tip or exposed end of rod <NUM> can then be inserted into the cannulation <NUM> of the fixation device <NUM>. The entire assembly <NUM> including the piggyback fixation piece <NUM> can then be rotated together to advance the anchor assembly <NUM> further into the bone hole for better securement, as seen in <FIG>. Here, the rod <NUM> may have an outer profile, for example, a hex profile, that matches the inner profiles of both the cannulation of the fixation device <NUM> and the cannulation of the piggyback fixation piece <NUM>, so that rotation of rod <NUM> also results in the simultaneous rotation and advancement of both fixation device <NUM> and piggyback fixation piece <NUM> further into the bone hole, and wrapping of the flexible strand <NUM> around the assembly. Preferably, after implantation, the proximal end of the entire assembly <NUM> is substantially flush with the surface of the bone. If any portion of the piggyback fixation piece <NUM> protrudes out of the bone hole and above the bone level after the combined assembly <NUM> is advanced into the bone hole to a desired depth and the flexible strand <NUM> has been tensioned to a desired amount (e.g., where slack in the flexible strand has been removed), any portion of the piggyback fixation piece <NUM> remaining outside of the bone hole may be removed, such as by burring down, shaving, or drilling, so that the finally implanted assembly <NUM> after such removal is substantially flush with the surface of the bone.

<FIG> illustrate another exemplary embodiment of the present invention. Parts or portions of the suture anchor assembly described with respect to <FIG> that are identical or similar to corresponding parts of the previous embodiments will use the same reference numbers, and the descriptions thereof will not be repeated. Suture anchor assembly <NUM>' may generally include a cannulated fixation device <NUM>' with a cannulation <NUM>' extending therethrough and a fixation exterior surface <NUM> configured to engage bone, such as via a bone hole or bone socket 99a, 99b, similarly as seen in <FIG> for the previous embodiments. The cannulation <NUM>' may have an inner profile that matches the inner profile of a rod <NUM> of an inserter <NUM>, for example, a hex profile, so that when the fixation device <NUM>' is placed around the rod <NUM>, rotation of rod <NUM> will also result in rotation of the fixation device <NUM>', for advancing fixation device <NUM>' into the bone hole. Fixation exterior surface <NUM> may comprise, for example, exterior threads or ridges, or be any known anchoring surface, for engaging and anchoring into the bone.

Suture anchor assembly <NUM>' also includes an implant <NUM>' configured to capture one or more repair flexible strands <NUM>, and to be rotatably coupled to the fixation device <NUM>'. Implant <NUM>' may comprise at least a first portion <NUM>', a second portion <NUM>', and a third portion <NUM>'.

First portion <NUM>' may be a shaft that has, for example, a substantially cylindrical cross-section dimensioned to fit in and freely rotate within a tube of rod <NUM> of inserter or driver <NUM>. The sizing therefore also allows insertion of first portion <NUM>' into cannulation <NUM>' of fixation device <NUM>'. In some embodiments, the first portion <NUM>' may further include a projection or other feature that allows for a releasable snap-in or other temporary fixation of the implant <NUM>' with the rod <NUM> when the first portion <NUM>' is inserted therein, while still allowing for rotation between the respective parts. In some embodiments, the first portion <NUM> further includes a transverse through hole or other feature that allows for attachment of a safety suture that is threadable proximally through the driver <NUM> and attachable, for example, to the handle or other portion at a proximal end of driver <NUM>, to further secure the parts to one another and prevent the implant <NUM>' from inadvertently disconnecting from or falling off of the driver <NUM>.

Second portion <NUM>' is positioned distally to first portion <NUM>', and has an outer engagement feature <NUM>' with a cross-section that is substantially the same as the cross-section of the rod <NUM>, a hex shape in the illustrated embodiment. Therefore, when first portion <NUM>' of implant <NUM>' is inserted in rod <NUM>, rod <NUM> and implant <NUM>' can be rotatably positioned relative to one another so that their respective hex profiles are aligned. In this manner, as the fixation device <NUM>' is advanced distally over rod <NUM> and reaches implant <NUM>', fixation device <NUM>' is capable of sliding past the distal end of rod <NUM> and around the second portion <NUM>' of implant <NUM>' in a form-fit manner, where engagement feature <NUM>' serves as a rotational stop mechanism, so that fixation device <NUM>' and implant <NUM>' are rotatable together in this configuration for wrapping flexible strand <NUM> around anchor assembly <NUM>' and reducing or eliminating slack in the flexible strand <NUM>. Here, the second portion <NUM>' may be, for example, <NUM>-<NUM> in length, so that the second portion <NUM>' has a long enough span to allow for a firm positive engagement between the second portion <NUM>' and the fixation device <NUM>'. In other embodiments, the second portion <NUM>' may be longer or shorter than <NUM>-<NUM>, based on the properties and requirements of the particular application. Optimally, the second portion <NUM>' should be short enough to still allow space for sufficient engagement between the rod <NUM> and fixation device <NUM>', so that the former will still be able to apply a sufficient torqueing force to the latter to further rotate or twist the assembly in the bone hole for at least one half or one (or more) additional turns, as needed, while also being long enough for the fixation device <NUM>' to sufficiently engage and turn the second portion <NUM>' at the same time, for wrapping the flexible strand <NUM> around the anchor assembly <NUM>' and taking out a desired amount of slack as the entire anchor assembly <NUM>' complex rotates together. In some embodiments, at least one full twist provides a significant amount of additional cable friction with the flexible strand <NUM> to augment fixation and further secure the anchor assembly <NUM>' in the bone.

Third portion <NUM>' is positioned distally to second portion <NUM>', and may be configured to capture at least one flexible strand <NUM>, via for example, an eyelet <NUM> or any other structure that is capable of capturing the flexible strand <NUM>.

In some embodiments, a transition between the first portion <NUM>' and the second portion <NUM>' can facilitate sliding of the fixation device <NUM>' over implant <NUM>' and ease engagement or capture of the second portion <NUM>' of implant <NUM>' by the fixation device <NUM>'. This can be accomplished, for example, by a slight circular cross-section that extends distally from the cylindrical first portion <NUM>' and rapidly increases in diameter and transitions in shape, leading into the hex shaped cross-section of the second portion <NUM>'. This or other type of transition can facilitate easier guiding of the inner hex shape of the fixation device <NUM>' over the hex shape of the second portion <NUM>' of implant <NUM>', and prevent, for example, the parts getting stuck or shearing before a full engagement between the parts. In some embodiments another transition between the second portion <NUM>' and the third portion <NUM>' can provide an axial stop that limits insertion of the implant <NUM>' into the cannulation <NUM>' of the fixation device <NUM>'. For example, the third portion <NUM>' can be formed in the shape of a rounded cone, a truncated cone, a trapezoid, or any other appropriate shape, such that the transition to the second portion <NUM>' forms an abutment or ledge by virtue of the proximal end of the third portion <NUM>' having a larger profile than the hex cross-section of the second portion <NUM>'. Such a transition may provide a hard stop against over-insertion of implant <NUM>' into fixation device <NUM>', for example, so that eyelet <NUM> of third portion <NUM>' remains external to fixation device <NUM>'. Various other types of stops can be employed to limit insertion of the implant <NUM>' into the fixation device <NUM>', for example, a distal region of the second portion <NUM>' having an enlarged hex profile to effect an interference fit with the fixation device <NUM>'.

The embodiment shown in <FIG> provide an alternative arrangement for rotationally fixing the fixation device <NUM>' with the implant <NUM>', so that rotation of the combined assembly <NUM>' will result in wrapping and reeling in of the flexible strand <NUM> that is secured to implant <NUM>', to reduce unwanted slack in the flexible strand <NUM>. In a similar manner, other embodiments can also be envisioned, where rotational fixation between a fixation device <NUM>' and implant <NUM>' can facilitate reduction of slack in an anchor assembly.

For example, a similar arrangement can also be applied to a push-type anchor instead of a swivel anchor, so that any existing slack can also be reduced from a flexible strand that is attached to bone via a push anchor using a similar rotating action. Here, all of the features of such an embodiment will be the same or similar to the example in swivel anchor embodiment shown in <FIG>, except that the fixation exterior surface will be arranged to be a plug-type, with for example, ribs or ridges instead of threads, to form a push anchor fixation device. Here, the fixation device still has a hex-shaped cannulation, so that the fixation device can be advanced over and engage the implant in a rotationally fixed manner. Here, the fixation device of the push anchor will be advanced without rotation during implantation, so that a smooth engagement between the parts should be more easily achieved. After the fixation device of the push anchor is engaged with the implant, the combined assembly can be rotated together to wrap the flexible strand or suture around the combined assembly, thereby reducing or eliminating the slack in the flexible strand.

In one exemplary embodiment, the method of tissue repair not being part of the present invention may be incorporated into known repair techniques, like a bridge repair, such as disclosed in commonly owned <CIT>. One or more suture anchor assemblies <NUM> may be anchored in respective bone holes <NUM>, in the manner described above, in a first medial row. Once the suture anchor assemblies <NUM> are installed, the tails <NUM> and <NUM> of the flexible strands <NUM> of each assembly <NUM> may be threaded through the damaged tissue <NUM> (<FIG>). The tails <NUM> and <NUM> may then be secured in bone holes in a second medial row or lateral row via anchors <NUM>. After all of the anchors have been implanted, any slack or laxity in the flexible strands <NUM>, for example, at the tails <NUM>, <NUM> that extend between the first medial row of anchors and the second medial row or lateral row of anchors, such as illustrated in <FIG>, may be eliminated or reduced using a method according to embodiments of the present invention. Here, the rod <NUM> of driver <NUM> may be reinserted into the proximal end of fixation device <NUM> and rotated, clockwise for example, to further rotate the combined units <NUM> including the fixation device <NUM> and implant <NUM>, typically at the second medial row or lateral row. This reels in or wraps the flexible strands <NUM> around the suture anchor assembly and winds up and removes the slack in the flexible strands <NUM> to tighten the bridge repair, as illustrated in <FIG>. In other embodiments, it may be possible to tighten the suture anchor assemblies in the first medial row in lieu of, or in addition to, tightening of the anchor assemblies in the second medial row or lateral row.

Claim 1:
A surgical anchor assembly (<NUM>), comprising:
a fixation device (<NUM>) having a proximal end (<NUM>), a distal end (<NUM>), a cannulation (<NUM>) extending therethrough, and a first engagement feature (<NUM>) formed in the cannulation (<NUM>) at or near the distal end (<NUM>); and
an implant (<NUM>) comprising a first portion (<NUM>) connectable to the distal end (<NUM>) of the fixation device (<NUM>) and having a second engagement feature (<NUM>) engageable with the first engagement feature (<NUM>), and a second portion (<NUM>) configured to capture a flexible strand (<NUM>);
wherein the end of the first engagement feature (<NUM>) forms a stop mechanism (<NUM>) configured to prevent rotational movement between the fixation device (<NUM>) and the implant (<NUM>) in at least one direction when the implant (<NUM>) is connected to the fixation device;
characterised in that the stop mechanism is opposite to the distal end (<NUM>),