WO2017035563A1

WO2017035563A1 - A tibial anchor arrangement for a short surgical graft used in anterior cruciate ligament knee joint reconstruction

Info

Publication number: WO2017035563A1
Application number: PCT/AU2016/000304
Authority: WO
Inventors: Matthew LIPTAK
Original assignee: Maxm Medical Pty Ltd
Priority date: 2015-09-02
Filing date: 2016-09-01
Publication date: 2017-03-09

Abstract

A tibial anchor arrangement for a short surgical graft used in an anterior cruciate ligament (ACL) reconstruction including an expansion sleeve adapted to be inserted into a hollowed tibial recess of a tibia bone of a damaged knee joint, wherein an external wall of the expansion sleeve wedges strands of a single synthetic strip against a wall of the hollowed tibial recess when the expansion sleeve has been inserted into the hollowed tibial recess and a screw internally receivable into the expansion sleeve, wherein as the screw is internally received into the expansion sleeve when the expansion sleeve has been inserted into the hollowed tibial recess, the external wall of the expansion sleeve laterally expands outwardly anchoring the strands of the single synthetic strip to the hollowed tibial recess.

Description

A TIBIAL ANCHOR ARRANGEMENT FOR A SHORT SURGICAL GRAFT USED IN ANTERIOR CRUCIATE LIGAMENT KNEE JOINT RECONSTRUCTION

TECHNOLOGICAL FIELD

[001] This invention relates to an arrangement for the insertion and fixation of the surgical graft used in the anterior cruciate ligament (ACL) and more particularly to an arrangement that provides a solid reinforced anchorage at the tibial end of the short surgical graft used in the ACL under the appropriate surgical graft loading so that there is no loss of integrity or previously established tension of the surgical graft once it is introduced and fixed within the tibial tunnel of the ACL knee joint reconstruction.

BACKGROUND DISCUSSION

[002] One recognised surgical technique used in an ACL reconstruction of a damaged knee joint involves the use of a dedicated interference screw.

[003] The interference screw that provides anchorage of the short surgical graft used in the ACL reconstruction is of a functional conical configuration so it can be screwed in to the tibial tunnel that has been hollowed and reamed from the Tibia as part of the preparation to be able to insert the surgical graft through the slightly widened anterior-medial arthroscopic portal so as to be positioned appropriately within the knee joint.

[004] In the original preparation of the short surgical graft there is the use of a single donor ligament graft along with a mechanism of looping the single strand around two adjustable tension mounts to provide a tensioned loop.

[005] Often as part of the pre-loading of the looped donor ligament graft, two synthetic strips are passed into each end of the loop wherein these synthetic strips using suitable instrumentation draws out the looped donor ligament draft to the appropriate length and diameter so it can be appropriately placed within the various tunnels and recesses in which it will then need to be inserted and fixed in placed when introduced to the knee joint undergoing the ACL reconstruction.

[006] Hence the synthetic strip that engages the tibial end of the short surgical graft used in the ACL reconstruction assists in being able to pull the prepared short surgical graft into the prepared tunnels and recesses of the knee joint and once the short surgical graft is in the correct position and tensioned to establish the requisite loading of the short surgical graft it is then fixed in placed.

[007] In conventional techniques once positioning and tensioning has been achieved then the interference screw is rotated where there is an actual sacrificial penetration of the walls of the hollow recess of the tibial tunnel as the conical screw threads its way into the tibia bone to be fixed in place.

[008] One of the main problems in utilising the interference screw to secure the short surgical graft at the tibial end is that to be appropriately anchored the strips are attached to the screw or alternatively at least cyclically rotated as the screws turns and cuts its way into the hollowed out tibial tunnel to be anchored in place.

[009] It is paramount that the short surgical graft is correctly positioned and tensioned so as to maximise knee joint stability and flexibility after the reconstructive surgery has been completed. The correct established loading which was finalised by pulling the strips through the tibial tunnel could be lost as when the conical interference screw is rotated into place to actually anchor the short surgical graft into place that corresponding movement of the synthetic strips during rotation of the interference screw can alter the positioning and tensioning that had originally been provided for the short surgical graft prior to the final fixation of the short surgical graft into the knee joint.

[010] It would be advantageous to be able to provide an arrangement that once the synthetic strip is passed into the tibial end of the looped short surgical graft and used in assisting passing the short surgical graft through the prepared tunnels and recesses of the ACL reconstruction to pull the short surgical graft into its appropriate position and tension within the knee joint, that the final fixation and anchoring of the short surgical graft at the tibial end can be achieved without rotation of the synthetic strip at the tibial end of the short surgical graft.

[01 1] Accordingly, it is an object of this invention to provide such an arrangement that will be able to fix and anchor into place the tibial end of the short surgical graft without rotation of the synthetic strip at the tibial end of the short surgical graft once the short surgical graft has been positioned and tensioned in the damaged knee joint.

SUMMARY OF THE INVENTION

[012] In one form of this invention there is provided a tibial anchor arrangement for a short surgical graft used in an anterior cruciate ligament (ACL) reconstruction, said arrangement including;

[013] an expansion sleeve, said expansion sleeve adapted to be inserted into a hollowed tibial recess of a tibia bone of a damaged knee joint under an ACL reconstruction, wherein an external wall of the expansion sleeve is adapted to wedge strands of a single synthetic strip against a wall of the hollowed tibial recess when the expansion sleeve has been inserted into the hollowed tibial recess;

[014] wherein the strands of the single synthetic strip are derived from the single synthetic strip being passed into a tibial end of a pre-loaded and looped short surgical graft;

[015] a screw internally receivable into the expansion sleeve, wherein as the screw is internally received into the expansion sleeve when the expansion sleeve has been inserted into the hollowed tibial recess, the external wall of the expansion sleeve laterally expands outwardly anchoring the strands of the single synthetic strip to the hollowed tibial recess.

[016] In preference the strands include a pair of strands. [017] In a further form of this invention there is provided a tibial anchor arrangement for a short surgical graft used in an anterior cruciate ligament (ACL) reconstruction, said arrangement including;

[018] a expansion sleeve, said expansion sleeve adapted to be insertable into a hollowed tibial recess of a tibia bone of a damaged knee joint under an ACL reconstruction, wherein an external wall of the general cylindrical longitudinal expansion sleeve is adapted to wedge opposing sides or ends of a single synthetic strip wherein the single synthetic strip has been passed into a tibial end of a preloaded and looped short surgical graft, wherein the opposing ends of the single length of the synthetic strip assist in passing the short surgical graft into configured recesses and tunnels in the damaged knee joint to place the short surgical graft in the correct positioning under correct load and tensioning to maintain appropriate stability for the knee joint to enable adequate flexibility for the expected flexion and extension of the knee joint movement post ACL reconstruction surgery;

[019] a screw internally receivable into the expansion sleeve, wherein as the screw is drawn internally into the expansion sleeve, the external wall of the expansion sleeve expands outwardly within the confines of the hollowed tibial recess of the tibia bone of the knee joint undergoing ACL reconstruction wherein the internal configuration of the expansion sleeve is configured to allow the internal receiving of the screws within the expansion sleeve to continue until the wedged opposing ends of the single length of synthetic strip is passed into the tibial end of the short surgical graft is anchored in a fixation so as to maintain the without rotation of the synthetic strip at the tibial end of the short surgical graft in the position that provided for the appropriate location and tensioning of the short surgical graft inserted into the knee joint under ACL reconstruction surgery.

[020] Advantageously the introduction of the unique expansion sleeve provides a mechanism where the initial positioning and tensioning of the synthetic strip engaging the tibial end of the short surgical graft does not need to be compromised as the short surgical graft is anchored into place. [021] Once the expansion sleeve has been tapped into the hollowed tibial recess of the tibia bone of the knee joint under ACL reconstruction, it can wedge the opposing ends of the synthetic strip into place and once the strips have been pulled to appropriate tension so that the short surgical graft per se is correctly tensioned and positioned to enable adequate flexibility for the expected flexion and extension of the knee joint movement post the ACL reconstruction surgery, the screw can be introduced internally into the expansion sleeve so it can expand out to anchor the synthetic strip in place so there is no subsequent movement once the short surgical graft has been fixed within the damaged knee joint under ACL reconstructive surgery.

[022] Advantageously, not only is there the ability to maintain the correct tensioning and positioning of the surgical graft during fixation within the knee joint because there is no movement of the synthetic strip, also as the screw does not engage the actual hollowed recess of the tibia bone there is no need for the destructive and sacrificial penetration of the screw to fracture and damage the tibia bone as part of the ACL reconstructive surgery which is the case when the interference screw technique is being used for fixing in place the short surgical graft.

[023] This very unique arrangement utilising the expansion sleeve provides a simple and non-destructive anchorage without, as introduced above, any altering of the initial tensioning and positioning provided by the synthetic strip engaging the tibial end of the short surgical graft.

[024] In preference the screw is threaded and internally the expansion sleeve is configured with a matching thread to that of the thread upon the screw.

[025] In preference the screw includes a male thread and preferably the internal configuration of the expansion sleeve includes a female corresponding thread to the male thread of the screw.

[026] Advantageously, the matching thread allows for convenient and simple cyclic screwing into the expansion sleeve of the screw so as to be appropriately internally received within the internal confines of the expansion sleeve to readily expand out the external wall of the expansion sleeve to fixedly wedge and anchor into place the opposing ends of the synthetic strip that is extended out from the tibial end of the short surgical graft.

[027] In preference the external wall of the expansion sleeve further includes longitudinal slots running along the longitudinal length of the expansion sleeve wherein the slots are configured to assist in positioning the opposing ends of the synthetic strip into a wedged position between the external wall of the expansion sleeve and the wall of the hollowed tibial recess of the tibia bone in the damaged knee joint undergoing ACL reconstructive surgery.

[028] Advantageously, in this preferred embodiment of including the longitudinal slots along the longitudinal length of the expansion sleeve allows for the expansion sleeve to be slotted into the tibial recess and then the opposing ends of the synthetic strip can still be further pulled and tensioned as required before ultimately the internally engaging screw is received into the expansion sleeve thereby expanding out the external wall to wedge and anchor into place the opposing ends of the synthetic strip once the synthetic strip has been pulled into position appropriately to provide the requisite tensioning and/or loading of the short surgical graft introduced into the damaged knee joint.

[029] This novel and inventive tibial anchor arrangement ensures that the screw providing anchorage does not interfere with the integrity of the hollow tibial recess of the tibia bone and is able to provide anchorage simply through the unique expansion mechanism involving the expansion sleeve internally receiving the screw thereby being able to naturally expand out rather than cause any fracturing or sacrificial destruction of the tibia bone.

[030] In preference the expansion sleeve and screw are made of material for conducive bio-interaction with the bone of the tibia to in time allow the expansion sleeve and/or the screw to be incorporated into the bone structure of the tibia.

[031] In preference the arrangement further includes an insertion tool. [032] In preference the insertion tool includes a main handle and a rod extension, wherein the rod extension terminates in a rounded head of similar dimensions so as to rest upon an internal skirt at the upper end of the expansion sleeve.

[033] In order now to describe the invention in greater detail a series of preferred embodiments will be presented with the assistance of the following illustrations and accompanying text.

BRIEF DESCRIPTION OF THE DRAWINGS

[034] Figure 1 is a perspective view of a prepared short surgical graft ready for insertion and fixation into a damaged knee joint undergoing an ACL reconstruction.

[035] Figure 2 is a schematic perspective representation of the use of a

conventional interference screw used within the prior art for fixation of the short surgical graft within the tibia.

[036] Figure 3 is a perspective view of the tibial anchor arrangement for a short surgical graft used in ACL reconstruction in a preferred embodiment of this invention.

[037] Figures 4a and 4b are schematic representations of the fixation and

anchorage of the tibial end of the prepared short surgical graft as shown in Figure 1 within the tibia of the damaged knee joint under the ACL reconstruction in a preferred embodiment of the invention.

[038] Figure 5 is a perspective view of an insertion rod used with the tibial anchor arrangement in a further preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[039] Figure 1 shows the prepared short surgical graft generally shown as (10) which will be used in the ACL reconstruction of the knee joint which includes the single strand of donor soft tissue graft (11 ) which has been wound around several times to establish a general looped configuration shown generally as (13) wherein the sutures (15a), (15b) allow two synthetic strips (12) and (14) to be passed into the respective ends (16) and (17) of the loop configuration (13) so as to assist in preloading the appropriate tension of the donor soft tissue graft (10) to establish the requisite length and diameter of the short surgical graft (10) to be inserted into the knee joint (20) including the femur (23) and tibia (24) undergoing ACL reconstruction.

[040] In Figure 2 the prepared short surgical graft (10) of Figure 1 is inserted and fixed within the knee joint (20) at the tibial end (17) of the short surgical graft (10) through the use of an interference screw (21 ) (shown in broken lines) within the tibia (24).

[041] The synthetic strip (14) that has passed into the tibial end (17) of the short surgical graft (10) provides two strands (22a) and (22b) which engage with the interference screw (21 ). Figure 1 also assists in illustrating the synthetic strip (14) and the two strands (22a) and (22b) that are adapted to engage the interference screw (21 ) shown in Figure 2.

[042] While not specifically shown in Figure 2, the interference screw (21 ) has been screwed into a hollowed out tibial channel of the tibia (24) in order to appropriately fix the short surgical graft (10) in place within the knee joint (20) at the tibia (24).

[043] The conical type interference screw (21 ) needs to penetrate and fixedly imbed itself within the tibial tunnel to establish the requisite anchorage once the short surgical graft (10) has been inserted within the tibial tunnel of the tibia (24).

[044] As introduced above, this technique of utilising the interference screw (21 ) to provide the fixation of the prepared short surgical graft (10) to the tibia (24) for anchorage means that given the interference screw (21 ) itself needs to be cyclically rotated and screwed into the hollowed out tibial tunnel of the tibia (24) in order to mesh itself within the bone structure of the tibia (24) to provide fixation, this rotation also means that the synthetic strip (14) and the respective strands (22a) and (22b) are rotated thereby placing potentially additional stresses which could weaken the integrity of the synthetic strip (14) and also more importantly potentially affect the preloaded tension which was originally established on the donor soft tissue graft (1 1 ) prior to and during insertion.

[045] Also as discussed above, not only is there a deterioration then in the performance of the prepared short surgical graft (10) being anchored using an interference screw (21 ) because of loss of the original pre-loaded tension placed on the donor soft tissue graft (1 1 ) but there is also the degradation to the tibia (24) itself wherein the tibial tunnel requires that the interference screw (21 ) penetrates and actually sacrificially engages the sides of the hollow recess of the tibial tunnel of the tibia (24) in order for the interference screw (21 ) to be anchored therein the tibia (24) to achieve the requisite fixation of the short surgical graft (10) at the tibial end (17).

[046] Figure 3 provides a preferred embodiment of a tibial anchor arrangement for a prepared short surgical graft used in an anterior cruciate ligament (ACL)

reconstruction shown generally as (30) which can overcome the shortcomings of the use of the interference screw (21 ) presented as part of the prior art illustration in Figure 2 when anchoring the prepared short surgical graft (10) to the tibia (24).

[047] The tibial anchor arrangement (30) includes an expansion sleeve (32) whereas best seen in Figures 4a and 4b, the expansion sleeve (32) is able to be inserted into the hollowed out tibial tunnel (33) of the tibia (34) which is part of the overall knee joint 31 which is undergoing an ACL reconstruction.

[048] The external wall (35) of the expansion sleeve (32) as illustrated by way of arrows (36a) and dashed lines (36b) in Figure 3 and (37) in Figures 4b, allows the external wall (35) of the expansion sleeve (32) to expand laterally outwards once the threaded screw (38) begins to be received into the internal hollow chamber (39) of the expansion sleeve (32).

[049] In the preferred embodiment shown in Figure 3 and Figures 4a and 4b there is a corresponding matched thread which includes the male thread (40) upon the screw (38) which then matches up with the internal female thread (41 ) within the hollow internal chamber (39) of the expansion sleeve (32).

[050] Advantageously by having a threaded match between threads (40) of the screw (38) and the internal configured matching female thread (41 ) allows simple rotation of the screw head (42) of the screw (38) to conveniently engage the expansion sleeve (32) so as to assist in expanding out the external wall (35) of the expansion sleeve (32).

[051] The expansion sleeve (32) also includes slots (45a) and (45b) that run along the longitudinal length of the expansion sleeve (32). As to be discussed shortly hereafter the slots (45a) and (45b) provide a location for the two strands (22a) and (22b) of the synthetic strip (14) to be placed in part there along the slots (45a) and (45b).

[052] As best illustrated in Figures 4a and 4b the strands (22a) and (22b) of the synthetic strip (14) are able to be wedged up against the side walls of the hollow tibial tunnel (33) once the screw (38) is rotated up into the expansion sleeve (32). As the strands (22a) and (22b) in part are positioned there along the slots (45a) and (45b) of the expansion sleeve, the interaction of the screw (38) as it rotates into the

expansion sleeve (32), causes the side wide (35) of the expansion sleeve (32) to expand out as shown by way of arrows (37) in Figure 4b. The external wall (35) of the expansion sleeve (32) begins to expand out thereby wedging and anchoring the two ends (22a) and (22b) of the synthetic strip (14) in place within the hollow tibial tunnel (33) of the tibia (34) so that the tibial end (17) of the prepared short surgical graft (10) as shown in figure 1 is anchored and fixed within the knee joint (31 ) without loss of any pre-loaded tension placed while being anchored to the tibia (34).

[053] The screw (38) for this invention rather than being an interference screw of the prior art that engages the bone of the tibia is alternatively uniquely received within the internal confines of the expansion sleeve (32), so the screw (38) need not physically and destructively engage with the sides of the hollowed out tibial tunnel of the tibia so there is no adverse effect to the integrity and structure of the tibia bone around the hollowed out tibial tunnel.

[054] Also as best seen in Figure 3 again as introduced above the expansion sleeve (32) also includes respective slots (45a) and (45b) which run down opposing sides of the expansion sleeve (32) wherein these two slots assist in being able to

conveniently align the strands (22a), (22b) of the synthetic strip (14) to more appropriately and conveniently align the strands (22a), (22b) as they are wedged up to the side wall of the hollow tibial tunnel (33).

[055] In Figure 5 a further feature of a preferred embodiment of the invention is shown utilising an insertion rod shown generally as (50).

[056] The insertion rod includes a main handle (46) and a rod extension (51 ) which terminates in a rounded head (53) of similar dimensions so as to rest upon a skirt (52) at the upper end of the expansion sleeve (47). The rounded head (53) also includes a pointed tip (54) that is adapted to extend into the internal chamber (56) of the expansion sleeve (47) shown by way of arrow (57).

[057] This skirt (52) of the expansion sleeve (47) and the rod head (53) of the insertion tool (50) allows for a reasonable comfortable slight frictional fit wherein the rod head (53) resting upon the skirt (52) allows the insertion tool (50) to assist in introducing the expansion sleeve (47) up into the hollowed out tibial recess (not shown) of the tibia of the knee joint where it then can be generally wedged in place to provide an initial fixation to then allow the expansion sleeve (47) to be anchored in place by introducing the screw (not shown) with mechanism of engagement with the expansion sleeve as discussed in relation to Figure 3 and Figures 4a and 4b.

[058] In the preferred embodiment shown in Figure 5 the rod section (51 ) of the tool (50) also includes line markings (55) along its length which assists in aligning up with the corresponding slots (48) running along opposing longitudinal sides (one side not shown) of the external wall of the expansion sleeve (47) to which the opposing ends or sides of the synthetic tape (not shown) would pass there along when the expansion sleeve (47) is inserted up into the recessed hollow tibial tunnel and fixation of the soft tissue graft is taking place in the knee joint.

[059] Advantageously this insertion tool (50) assists in being able to make sure that firstly the expansion sleeve (47) is wedged, in appropriate orientation so that the opposing slots (48) (one slot of the opposing slots not shown) of the expansion sleeve (47) are aligned for the strands of the synthetic strips (not shown) to be tensioned to preload the surgical graft as it is inserted and then finally fixed and anchored into place within the knee joint undergoing ACL reconstruction.

[060] Hence in some instances the insertion tool (50) can assist in guiding the expansion sleeve (47) into place and as the synthetic strips are positioned along the opposing slots (48) of the expansion sleeve additional pulling down of the strips can further take place in order to establish the requisite tensioning or pre-loading of the short surgical graft within the damaged knee joint and once the surgeon is

comfortable that the tensioning applied to the short surgical graft has been achieved, the insertion tool (50) can be withdrawn and the screw referenced when describing the engagement with the expansion sleeve in Figure 3 and Figures 4a and 4b can be inserted so that there is then anchoring of the tibial end of the prepared short surgical graft into place within the tibia of the damaged knee joint.

Claims

1 . A tibial anchor arrangement for a short surgical graft used in an anterior cruciate ligament (ACL) reconstruction, said arrangement including; an expansion sleeve, said expansion sleeve adapted to be inserted into a hollowed tibial recess of a tibia bone of a damaged knee joint under an ACL reconstruction, wherein an external wall of the expansion sleeve is adapted to wedge strands of a single synthetic strip against a wall of the hollowed tibial recess when the expansion sleeve has been inserted into the hollowed tibial recess; wherein the strands of the single synthetic strip are derived from the single synthetic strip being passed into a tibial end of a pre-loaded and looped short surgical graft; a screw internally receivable into the expansion sleeve, wherein as the screw is internally received into the expansion sleeve when the expansion sleeve has been inserted into the hollowed tibial recess, the external wall of the expansion sleeve laterally expands outwardly anchoring the strands of the single synthetic strip to the hollowed tibial recess.

2. The tibial anchor arrangement of claim 1 wherein the strands include a pair of strands.

3. The tibial anchor arrangement of claim 2 wherein the external wall of the expansion sleeve includes a pair of longitudinal slots to allow the pair of strands of the synthetic strip to be locatable in part therein.

4. The tibial anchor arrangement of anyone of claims 1 to 3 wherein the screw is threaded and internally received into the expansion sleeve by a matching thread configured internally within the expansion sleeve.

5. The tibial anchor arrangement of claim 4 wherein the screw includes a male thread and the internal configuration of the expansion sleeve includes a female corresponding thread.

6. The tibial anchor arrangement of claim 4 or 5 wherein the screw includes a screw head and wherein the screw head includes a slot, wherein the slot is adapted to engage a screw driving tool.

7. The tibial anchor arrangement of claim 1 wherein the expansion sleeve is generally of a longitudinal cylindrical form.

8. The tibial anchor arrangement of claim 1 wherein the expansion sleeve and the screw are made of material for conducive bio-interaction with bone of the tibia wherein upon a passing of time once the expansion sleeve is anchored in the tibia, the expansion sleeve and the screw become incorporated into bone structure of the tibia.

9. The tibial anchor arrangement of claim 1 further including an insertion tool.

10. The tibial anchor arrangement of claim 9 wherein the insertion tool includes a main handle and a rod extension, wherein the rod extension terminates in a rounded head of similar dimensions to a skirt at the upper end of the expansion sleeve.

1 1. The tibial anchor arrangement of claim 10 wherein the rounded head includes a pointed tip adapted to extend into an internal chamber of the expansion sleeve.

12. The tibial anchor arrangement of claim 10 or 1 1 wherein the rod extension includes line markings configured to align up the pair of strands of the single synthetic strip.