Patent Application
20240285326
This invention relates to methods of removing implants embedded in surrounding tissue material and to associated apparatus for use in removing implants. More particularly, this invention relates to methods and apparatus for removing implants, such as femoral implants, from surrounding tissue material, e.g., in a human or animal body.
It is often necessary to remove implants that have previously been inserted, for example, where the implant has become loose, or the tissue surrounding the implant is infected. The failure rate of femoral implants, necessitating removal and insertion of a new implant, is believed to be about 10%.
Implants may generally be cemented or uncemented into position. For uncemented implants bony ingrowth is encouraged, which serves to secure the implant. Fibrous tissue may grow and encapsulate the implant.
A disadvantage of many known approaches is that to remove the implant any cement and bony ingrowth around the implant needs to be removed. In practice this results in large amounts of surrounding tissue (e.g., bone) being taken out, with a significantly larger cavity being left behind. The surgery is therefore relatively invasive and more expensive. In addition, the recovery from the surgery takes longer, and the patient cannot load bear through the new implant for some time after the surgery. For uncemented implant removal, in the majority of cases an extended trochanteric osteotomy has to be carried out to remove the implant. This has to be wired up to secure the revision implant.
Common approaches to removing implants involve the use of standard osteotome devices. Approaches are also described in WO2011/045568, WO2017/032993 and WO2019/224561, each of which use a drill guide or targeting device to carry out a method of removing an implant, e.g., a femoral implant, that has previously been inserted in a human or animal body. The content of each of these documents is incorporated in its entirety by reference.
It can still be difficult to remove collared implants, however. In the situation where the implant is collared, the collar can restrict the access that can be achieved by devices. Specifically, the presence of a collar on the medial side at the shoulder, which usually extends from the medial border of the shoulder to halfway laterally, will prevent the clearance of the medial surface of the implant using the medial-lateral clearance device of WO2019/224561.
In addition, for both collared and collarless implants, there is still a need to make the removal of the implant easier and more accurate. It is desirable to have as much control as possible, to reduce the chance of damage to the femur.
The present invention provides a new piece of apparatus that can be used in the known approaches, such as those described in WO2011/045568, WO2017/032993 and WO2019/224561, to improve the final step of releasing the implant before removal.
In this regard, the present invention provides a wire delivery device that can be used to clear at least the medial aspect of an implant. It may optionally and usefully also be utilised to clear the lateral aspect of the implant.
The wire delivery device of the invention can, in particular, be useful for clearing at least the medial aspect of a collared implant, but it is not limited to this use. In one embodiment the device is used for a collarless implant.
The wire delivery device can be used in a method of removing an implant, especially a femoral implant, from the surrounding tissue, the method comprising:
The wire delivery device of the invention is suitably used in at least the step of clearing the medial aspect of the implant by removing bony ingrowth located at the antro-medial edge of the implant and at the postro-medial edge of the implant.
In one embodiment, the method of removing an implant comprises:
Step 6) is optional. The access tunnels as formed in step 4) may already be wide enough to move onto step 7) after step 5), especially if the access tunnels are made using a chevron chisel.
Optionally, and in many cases preferably, step 9) may be used to clear the lateral aspect of the implant as well as the medial aspect of the implant. Thus step 9) may additionally use a wire delivery device according to the present invention to clear the lateral aspect of the implant by removing bony ingrowth located at the antro-lateral edge of the implant and at the postro-lateral edge of the implant.
Thus, in some embodiments, step 8) may be omitted and step 9) may be used to clear the lateral aspect of the implant as well as the medial aspect of the implant.
In one embodiment, the brace targeting device as shown in
In one embodiment, the method of removing an implant comprises:
Alternatively, step h) may be omitted and in step i) the wire delivery device may be used to clear the lateral aspect of the implant as well as the medial aspect of the implant.
In one embodiment, step 4) or step d) creates initial access tunnels, anteriorly and posteriorly, and step 6) or step f) creates a sub access tunnel within each initial access tunnel. The sub access tunnel may be deeper than the initial access tunnel but less wide than the initial access tunnel. Each sub access tunnel may be sized to facilitate use of the wire delivery device in step 9) or step i) and therefore each may suitably be sized to receive one of the elongate bodies of the wire delivery device.
It may be that the initial access tunnels each have a maximum depth of about 1 to 2 mm, such as about 1 mm and they may optionally but preferably have a maximum width of about 4 to 12 mm, such as about 10 mm. It may be that the sub access tunnels each have a maximum depth of about 1.5 to 2 mm, such as about 1.5 mm and they may optionally but preferably have a maximum width of about 4 to 7 mm, such as about 5 mm.
In one embodiment, the brace targeting device as shown in
In one embodiment, the method of removing an implant comprises:
Alternatively, step h) may be omitted and in step i) the wire delivery device may be used to clear the lateral aspect of the implant as well as the medial aspect of the implant.
In one embodiment, the brace targeting device as shown in
In one embodiment of any of the above-disclosed methods of removing an implant, only cutting devices with a thickness of 2 mm or less (or 1.5 mm or less) are used. This can be beneficial in terms of minimising loss of tissue around the implant.
The present invention provides the novel wire delivery device individually. The present invention also provides a kit comprising the novel wire delivery device together with any one or more of the above-mentioned apparatus/devices, for example with any two or more, or any three or more, or any four or more such devices. In one embodiment there is a kit comprising all of the above-mentioned apparatus/devices.
In one embodiment two or more, such as three or more, of the devices have the same or similar width at their proximal end. It may be that all of the devices in the kit have the same or similar width at their proximal end. This provides the option that a universal handle could be used which would fit onto multiple devices. In one embodiment, the width at the proximal end for each device is relatively narrow, e.g. from 5 to 10 mm. This has the benefit of being able to slide the same brace onto for multiple devices in the kit; therefore a re-useable brace could be used.
In one embodiment, one or more or two or more, such as three or more, of the devices may be provided as single-use pre-packed sterilised devices. The skilled person will appreciate that useful forms of sterilisation include gamma (irradiation) sterilisation or ethylene oxide (EtO) sterilisation. This is in particular foreseen for the devices within the kit that are cutting devices. It may usefully be that all cutting devices are provided as single-use pre-packed sterilised devices.
Further parts of the kit may optionally be provided as single-use pre-packed sterilised products, e.g. a brace sleeve may be. provided as a single-use pre-packed sterilised product.
In particular, in one embodiment the novel wire delivery device is provided in combination with a chevron chisel according to WO2019/224561 and/or with a curette according to WO2019/224561 and/or with a medial-lateral clearance device according to WO2019/224561.
The novel wire delivery device of the invention comprises:
The first length of cutting wire and second length of cutting wire can be a single piece of wire, such that the medial and lateral cutting wire arcs together form a closed wire loop. Alternatively, the first length of cutting wire and second length of cutting wire can be separate pieces of wire. The wire is suitably annealed wire, e.g., medical grade titanium or titanium alloy or stainless steel.
It may be that the wire delivery device is provided in a form where the first and second lengths of cutting wire are provided as part of the device, e.g., as a kit. In one preferred embodiment the first and second lengths of cutting wire are provided as part of the device and are secured in place, such that the medial and lateral cutting wire arcs are provided, each extending between the first elongate body and the second elongate body.
When using the wire delivery device of the invention, the medial and lateral cutting wire arcs can be used to cut by:
If the implant is collared, it will be appreciated that the medial loop must be located on the medial side of the implant in a position inferior to the collar, e.g., it may be hooked over the collar.
The wire arcs will not be directly exposed to the bone because they are secured in the wire receiving portions and these are spaced from the distal end. The distal end is therefore usefully blunt, to protect the bone from the wire. However, it is also envisaged that the distal ends of the first and second elongate bodies may be chisel like, e.g. with a 45 degree chisel angle. This can be advantageous in terms of facilitating an easy transition into the bone-implant interface. Also, it will assist with keeping the wire delivery device pushed against the implant.
The first and second elongate bodies are pushed in an alternating motion to cause the wire arcs to cut, directing the force distally. As the medial cutting wire arc traverses distally, it will clear the bone-implant interface medially. As the lateral cutting wire arc traverses distally, it will clear the bone-implant interface laterally. The distal movement of the first and second elongate bodies may be carried out manually, e.g., using a hammer, or a reciprocating mechanism (e.g. reciprocating saw) could be used to drive each of the first and second elongate bodies.
In a preferred first embodiment, the novel wire delivery device of the invention comprises:
As noted above, in one preferred embodiment sub access tunnels have been formed for receiving the first and second elongate bodies, and therefore in one preferred embodiment the first and second elongate bodies are located in and pushed along these sub access tunnels.
The cutting wire arcs will not be directly exposed to the bone because they are secured in the wire receiving slots and these are spaced from the distal end. The distal end is therefore usefully blunt, to protect the bone from the wire. However, it is also envisaged that the distal ends of the first and second elongate bodies may be chisel like, e.g. with a 45 degree chisel angle. This can be advantageous in terms of facilitating an easy transition into the bone-implant interface. Also, it will assist with keeping the wire delivery device pushed against the implant.
The first and second elongate bodies are pushed in an alternating motion to cause the cutting wire arcs to cut, directing the force distally. As the medial cutting wire arc traverses distally, it will clear the bone-implant interface medially. As the lateral cutting wire arc traverses distally, it will clear the bone-implant interface laterally. The distal movement of the first and second elongate bodies may be carried out manually, e.g., using a hammer, or a reciprocating mechanism (e.g. reciprocating saw) could be used to drive each of the first and second elongate bodies.
In an alternative second embodiment, the novel wire delivery device of the invention comprises:
When using the second wire delivery device of the invention, once the wire loop is located and secured in the first and second wire guidance channels, the cutting wire arcs can be used to cut by:
As noted above, in one preferred embodiment sub access tunnels have been formed for receiving the first and second elongate bodies, and therefore in one preferred embodiment the first and second elongate bodies are located in and pushed along these sub access tunnels.
The wire loop will not be directly exposed to the bone because it is secured in the wire guidance channels and these are spaced from the distal end. The distal end is therefore usefully blunt, to protect the bone from the wire. However, it is also envisaged that the distal ends of the first and second elongate bodies may be chisel like, e.g. with a 45 degree chisel angle. This can be advantageous in terms of facilitating an easy transition into the bone-implant interface. Also, it will assist with keeping the wire delivery device pushed against the implant.
The first and second elongate bodies are pushed in an alternating motion to cause the wire arcs to cut, directing the force distally. As the wire traverses distally, it will clear the bone-implant interface medially (and optionally laterally as well). The distal movement of the first and second elongate bodies may be carried out manually, e.g., using a hammer, or a reciprocating mechanism (e.g. reciprocating saw) could be used to drive each of the first and second elongate bodies.
In one embodiment, the brace targeting device as shown in
The present invention permits an implant, especially a femoral implant, to be more readily removed from the surrounding tissue and with significantly less loss of tissue around the implant. The procedure is less invasive and generally will involve loss of tissue around the implant of the order of about 0.6 mm-1 mm, or even only about 0.6 mm, or even less, in each direction.
As the skilled reader will appreciate, a femoral implant has a tapered body. This extends from a broader proximal end, which provides a shoulder portion, to a narrower distal end. A neck extends from the proximal end, and a head extends from the neck.
The procedure generally involves firstly creating two access tunnels in the surrounding tissue, one at the anterior of the implant and one at the posterior of the implant, with each access tunnel extending from an access point at the proximal surface of the surrounding tissue, which can be accessed by a person carrying out the procedure, to a point in the surrounding tissue that is located beyond the distal end of the implant (e.g. at a distance of about 0.3 to 1.2 cm beyond the distal end, and preferably 0.5 to 1 cm beyond the distal end). The anterior access tunnel is spaced from and substantially parallel to the anterior surface of the implant and the posterior access tunnel is spaced from and substantially parallel to the posterior surface of the implant.
The anterior access tunnel is preferably spaced from the anterior surface of the implant by a distance of from 0.1 to 10 mm, such as from 0.1 to 8 mm or from 0.1 to 6 mm; in one preferred embodiment the distance is less than 5 mm, preferably less than 4 mm, or less than 3 mm, or less than 2 mm, such as from 0.1 to 2 mm. Most preferably the distance is less than 1 mm, such as from 0.3 mm to 1 mm and especially such as from 0.5 to 1 mm (preferably 0.5 mm).
The posterior access tunnel is preferably spaced from the posterior surface of the implant by a distance of from 0.1 to 10 mm, such as from 0.1 to 8 mm or from 0.1 to 6 mm; in one preferred embodiment the distance is less than 5 mm, preferably less than 4 mm, or less than 3 mm, or less than 2 mm, such as from 0.1 to 2 mm. Most preferably the distance is less than 1 mm, such as from 0.3 mm to 1 mm and especially such as from 0.5 to 1 mm (preferably 0.5 mm).
The access tunnels may be any shape in cross section, provided they are elongate. It will be appreciated that their dimension that extends substantially perpendicular to the anterior surface or the posterior surface should be relatively small, so as to minimise unnecessary removal of surrounding tissue, e.g. from 0.5 mm to 5 mm. However, their dimension that extends substantially parallel to the anterior surface or the posterior surface can be larger, if desired, because the method is seeking to create a space that extends over the width of the anterior surface and the posterior surface of the implant. Therefore this dimension can be larger than 5 mm without leading to unnecessary removal of surrounding tissue.
The access tunnels may be elongate bores with round cross sections, e.g. substantially circular cross sections. The diameter of the access tunnels may suitably be from 0.5 mm to 5 mm, preferably from 1 mm to 4 mm, e.g. from 2 mm to 4 mm or from 2.5 mm to 3.5 mm. However, other cross sectional shapes can be envisaged for the access tunnels, e.g. rectangular or square. The dimension that extends substantially perpendicular to the anterior surface or the posterior surface may suitably be from 0.5 mm to 5 mm, preferably from 1 mm to 4 mm, e.g. from 2 mm to 4 mm or from 2.5 mm to 3.5 mm. Thus the minimum diameter of the access tunnels (i.e. the smallest distance, when considered as a straight line, from one point on the perimeter to another point on the perimeter via the centrepoint) should fall within this range.
The skilled reader will appreciate that in order to make the procedure as minimally invasive as possible, the tunnel as formed should have a dimension that extends substantially perpendicular to the anterior surface or the posterior surface that is as small as possible. However, there is also a desire to remove as much material as possible in a direction substantially parallel to the anterior surface or the posterior surface, to make subsequent steps easier. Therefore the use of two or more tunnels parallel to one another on the anterior surface and/or the posterior surface can be beneficial, because these can each have smaller diameters, and therefore minimise the intrusion into surrounding tissue, but overall these combine to remove more material in a direction substantially parallel to the anterior surface or the posterior surface.
For essentially the same reasons, the use of an access tunnel that has an elongate rather than a circular cross section can be beneficial. In this regard, the cross section should be such that the smallest dimension is in the direction that extends substantially perpendicular to the anterior surface or the posterior surface, whilst the largest direction is in the direction that extends substantially parallel to the anterior surface or the posterior surface. The access tunnel can, for example, have a rectangular shaped cross section.
The present invention also provides a method in which at least the wire delivery device of the invention is used.
The first stage of the procedure is suitably effected using a targeting device, which ensures the access tunnels are created at the required locations on the anterior and posterior of the implant. It will be appreciated that the angle of the tunnels is important, because it is desired that the tunnels run all the way along the implant and converge at a location beyond the distal end of the implant.
The access tunnels may be created using conventional tools, such as a drill and drill bits, or a chisel, or a reciprocating saw, or a K-wire. Of course, the tool used could be bespoke instead. The key feature is that the tool is elongate and has at least one edge that is sufficiently sharp that when the tool is operated it can be used to create access tunnels on the anterior and posterior of the implant. Preferably, a chevron chisel according to WO2019/224561 is used.
The targeting device may, in one embodiment, be a drill guide of the type described in WO2011/045568. Such a drill guide is suitably secured on a projection of a femoral implant.
The targeting device may, in another embodiment, be a targeting kit of the type described in WO2017/032993. Such a targeting kit is suitably secured on the head or neck of a femoral implant. If such as targeting kit is used, the first and second guide members may have bores that have any shape cross section, but in particular may have a circular cross section, a square cross section or a rectangular cross section.
However, in a preferred embodiment, the targeting device is a targeting kit of the type described in WO2019/224561, which is suitable for being secured on the shoulder of a femoral implant. As the skilled person will appreciate, it is standard for the shoulder of a femoral implant to have a recess portion, which may optionally have female screw threads provided inside. This recess is provided in implants as standard, so that the distal end of an impactor can engage (e.g. by threaded engagement) into the recess to push and impact the femoral implant into the pre-prepared proximal part of the patient's femur, to the correct depth. The targeting device of WO2019/224561 makes use of this recess portion to engage with the femoral implant.
The targeting device of WO2019/224561, which may be used in the present invention, comprises:
The convergence between the anterior angled channel and the posterior angled channel may be in the range of 2 to 7 degrees, e.g. from 2 to 6 degrees, preferably 4 or 6 degrees. This is the actual angle of convergence between the anterior angled channel and the posterior angled channel when the targeting device is secured onto the implant.
Preferably the arrangement of the angled channels is symmetrical. In one embodiment, each has a fixed angle, with reference to the elongate axis of the elongate body in which the channel is provided, which is in the range of from 1 to 4 degrees, e.g. from 2 to 4 degrees, such as 2 or 3 degrees.
The first contact element at the distal end of the anterior guide member may be a lip or a leg that extends from the distal end of the elongate body. Likewise, the second contact element at the distal end of the posterior guide member may be a lip or a leg that extends from the distal end of the elongate body.
The engagement member comprises an elongate body with an engagement protrusion at its distal end. This engagement protrusion is sized and shaped to be received in a recess portion on the shoulder of the implant. The skilled person will appreciate that a femoral implant will, as standard, include a recess portion on the shoulder which receives an impactor when the implant is being implanted. This recess is located on the shoulder at the proximal end of the central axis. Therefore the engagement protrusion ensures central alignment for the targeting device on the femoral implant.
Each connector rail slideably connects the anterior guide member and the posterior guide member via the engagement member. Each connector rail is received in a connection bore in the anterior guide member and a connection bore in the posterior guide member. Each connector rail may optionally be provided with a spring or other biasing means that serves to bias the anterior guide member and the posterior guide member into their release positions. The biasing force of the spring or other biasing means can be overcome by use of the adjustment system to move the anterior guide member and the posterior guide member into their holding positions.
The adjustment system may comprise a threaded adjustment member, such as a screw. The threaded adjustment member may suitably have a diameter of from 4 to 6 mm. It may, in one embodiment, have a 1 mm thread. In particular, it is preferred that the adjustment system comprises a double ended screw, also known as a left- and right-screw or a right- and left-screw. As the skilled reader will appreciate, such a screw has a first end portion with a right-hand screw thread and a second end portion with a left-hand screw thread, and a non-threaded section in the middle, between the two threaded end portions. This is a beneficial system because it means that the anterior guide member and the posterior guide member move simultaneously. This is the case both for movement towards the engagement member and away from the engagement member.
Additional Checking Devices to be Used with the Targeting Device
Optionally the targeting device described above is used in combination with a medial targeting device, e.g. as described in WO2019/224561. This device can be used to double check the alignment of the targeting kit in the antero-posterior plane before the tunnels are drilled.
When a medial targeting device is used, the targeting device is provided with an alignment slot located at the proximal end of the engagement member. This alignment slot is in longitudinal alignment with the engagement protrusion of the engagement member.
Optionally the targeting device described above is used in combination with an external targeting device, e.g. as described in WO2019/224561. This device can be used to double check the alignment of the targeting kit in the anterior-posterior plane before the tunnels are drilled.
In one embodiment, the external targeting device may comprise:
If the plane of the angled tip is not aligned with the centreline in the anterior-posterior plane, the location of the targeting device can be adjusted until the angled tip does align with the centreline in the anterior-posterior plane.
Cutting Tools to be Used with the Targeting Device
The access tunnels may be created using a tool that is elongate and has at least one edge that is sufficiently sharp that when the tool is operated it can be used to create access tunnels on the anterior and posterior of the implant. It may be a conventional tool, such as a drill and drill bits, or a chisel, or a reciprocating saw, or a K-wire.
It may preferably be that a chevron chisel according to WO2019/224561 is used. This chevron chisel comprises:
Preferably the angled cutting point is located substantially centrally between the first elongate edge and the second elongate edge.
In one embodiment, it is envisaged that the distal end of the chevron chisel has a 40 to 60 degree chisel angle, e.g. a 45 degree chisel angle or a 60 degree chisel angle.
The optional second stage of the procedure involves removing bony ingrowth located adjacent to the anterior access tunnel, and removing bony ingrowth located adjacent to the posterior access tunnel and the posterior surface of the implant. The intention of this step is to extend the size of the access tunnels.
Of course, it may be that the first stage creates initial access tunnels that are of sufficient size that the second stage can be omitted.
It may be that the anterior access tunnel is broadened in a plane that is substantially parallel to the anterior surface of the implant (increased width) and/or in a plane that is substantially perpendicular to the anterior surface of the implant (increased depth).
It may be that the posterior access tunnel is broadened in a plane that is substantially parallel to the posterior surface of the implant (increased width) and/or in a plane that is substantially perpendicular to the posterior surface of the implant (increased depth).
This may be carried out using another chevron chisel according to WO2019/224561, as described above. For example, a chevron chisel that is larger in at least one dimension than the tool used to make the access tunnel may suitably be used.
Alternatively, this step may be carried out using a chevron osteotome device of WO2019/224561. The chevron osteotome device of WO2019/224561 comprises:
In one embodiment, the first stage creates initial access tunnels, anteriorly and posteriorly, and the second stage creates a sub access tunnel within each initial access tunnel. The sub access tunnel may be deeper than the initial access tunnel but less wide than the initial access tunnel. Each sub access tunnel may be sized to facilitate use of the wire delivery device in the fifth stage and therefore each may suitably be sized to receive one of the elongate bodies of the wire delivery device.
It may be that the initial access tunnels each have a maximum depth of about 1 to 2 mm, such as about 1 mm and they may optionally but preferably have a maximum width of about 4 to 12 mm, such as about 10 mm. It may be that the sub access tunnels each have a maximum depth of about 1.5 to 2 mm, such as about 1.5 mm and they may optionally but preferably have a maximum width of about 4 to 7 mm, such as about 5 mm.
The third stage of the procedure involves removing bony ingrowth located between the implant and the femur in the anterior aspect, and removing bony ingrowth located between the implant and the femur in the posterior aspect. The intention of this step is to reduce the amount of bony ingrowth between the implant and the femur in the anterior aspect and to reduce the amount of bony ingrowth between the implant and the femur in the posterior aspect.
In one embodiment, this step may clear a space at the bone-implant interface to both the medial and lateral edges of the implant.
This third stage may be carried using the curette device of WO2019/224561 (or a set of two or more curette devices according to WO2019/224561). The curette device of WO2019/224561 comprises:
The elongate body of the curette device suitably has a diameter that is equal to or slightly less than the diameter of the now-widened access tunnel. For example its diameter may be less than the diameter of the access tunnel by 1 mm or less, e.g. from 0.1 to 0.5 mm.
The cutting edge is located towards the proximal end of the cutting portion, i.e. such that cutting occurs as the curette device is withdrawn from the tunnel rather than as it is pushed into the tunnel.
The cutting edge may be sharp along its length, such that all of the cutting edge can serve to cut away bony ingrowth located between the access tunnel and the surface of the implant. However, it will be appreciated that the device will also be effective if only some of the length of the cutting edge is sharp. In the present invention, it is only necessary that the cutting edge is sharp at its distal end, i.e. the cutting point. Therefore the cutting edge is sharp at the cutting point and is optionally sharp along some, most or all of the remainder of the cutting edge.
In a preferred embodiment the curette device comprises a second cutting portion, located between the second elongate edge and the distal end of the elongate body. For example, a second cutting portion may be provided on a curved or angled edge that extends between the second elongate edge and the distal end of the elongate body. The second cutting portion suitably comprises teeth. Alternatively or additionally, the second cutting portion may comprise a sharp edge.
The fourth stage of the procedure involves clearing the lateral aspect of the implant by removing bony ingrowth located at the antro-lateral edge of the implant and at the postro-lateral edge of the implant. Thus the lateral surface of the implant is cleared of bony ingrowth at or near to where it adjoins the anterior surface of the implant and at or near to where it adjoins the posterior surface of the implant.
This stage may be carried out using the medial-lateral clearance device of WO2019/224561 (or a set of two or more medial-lateral clearance devices according to WO2019/224561). The medial-lateral clearance device of WO2019/224561 comprises:
The cutting portion has an inner surface that is flat and which connects with the first elongate edge of the elongate body at a substantially 90 degree angle, e.g. at an angle of from 90 to 100 degrees.
In one embodiment, the distal end of the medial-lateral clearance device is blunt, e.g. it may be curved. In another embodiment, the distal end of the medial-lateral clearance device is angled, e.g. it may have a chevron shape. In one such embodiment, the distal end of the medial-lateral clearance device comprises a first angled face and a second angled face which meet at an angled point, wherein the first angled face extends at an angle of from 30 to 60 degrees, (e.g. from 30 to 50 degrees, or from 40 to 50 degrees, or from 40 to 60 degrees), from the first elongate edge when measured with respect to the elongate axis of the elongate body, and the second angled face extends at an angle of from 30 to 60 degrees, (e.g. from 30 to 50 degrees, or from 40 to 50 degrees, or from 40 to 60 degrees), from the second elongate edge when measured with respect to the elongate axis of the elongate body.
In one embodiment, it is envisaged that the distal end of the medial-lateral clearance device has a 40 to 60 degree chevron angle, e.g. a 45 degree chevron angle or a 60 degree chevron angle.
The cutting portion may be formed as an integral part of the medial-lateral clearance device. Alternatively, the cutting portion may be formed as a separate part that is then attached to the elongate body, e.g. by laser welding. The cutting portion is attached to connect with the first elongate edge of the elongate body at a substantially 90 degree angle, e.g. at an angle of from 90 to 100 degrees.
This stage may, alternatively, be carried out using the wire delivery device according to the invention, as described below. In other words, in one embodiment the wire delivery device according to the invention is used to clear the medial aspect of the implant and to clear the lateral aspect of the implant.
The fifth stage of the procedure involves clearing the medial aspect of the implant by removing bony ingrowth located at the antro-medial edge of the implant and at the postro-medial edge of the implant. Thus the medial surface of the implant is cleared of bony ingrowth at or near to where it adjoins the anterior surface of the implant and at or near to where it adjoins the posterior surface of the implant.
This stage is carried out using a wire delivery device according to the invention.
The novel wire delivery device of the invention comprises:
By having a cutting wire arc both medially and laterally, the device drives distally along the midline axis of the implant and femur. This therefore makes the device more stable and easy to use, and avoids the device being driven into the medial cortex of the femur.
Although the first elongate body and the second elongate body may be different, in a preferred embodiment they have the same size and shape.
In one embodiment, the first elongate body is in the form of a flat plate and the second elongate body is in the form of a flat plate. In one embodiment the depth (thickness) of the plate is from 0.2 to 3 mm, such as from 0.5 to 2.5 mm, preferably from 1 to 2 mm, such as from 1 to 1.5 mm, e.g. 1 mm or 1.2 mm or 1.5 mm.
The distal end of each elongate body is not intended to be a cutting end and therefore these ends may be blunt. In one embodiment, distal end of each elongate body is angled but blunt, i.e. with no sharp edges. In one embodiment, each elongate body may have a chisel like distal end, e.g. with a 45 degree chisel end. This can be advantageous in terms of facilitating an easy transition into the bone-implant interface. Also, it will assist with keeping the wire delivery device pushed against the implant.
Each elongate body may be provided with an integral handle at its proximal end or may be provided with a handle at its proximal end in use.
Each elongate body may be formed from any suitable medical grade metal or metal alloy, e.g. medical grade stainless steel.
In a first embodiment, the novel wire delivery device of the invention comprises:
The length of each elongate body may, for example, be 200 mm or more, such as from 200 mm to 300 mm, e.g. from 225 mm to 250 mm.
The maximum width of each elongate body (not including any handle) may suitably be from 6 mm to 10 mm, especially from 7 mm to 9 mm, e.g. about 7.5 mm or about 7.75 mm.
In one embodiment, each elongate body includes a narrower portion towards the distal end. In particular, there may be a narrowing of the width of the elongate body at or near to the location where the wire receiving slots are provided. For example, each elongate body may include a tapered portion at or near to the location where the wire receiving slots are provided.
Each elongate body may, for example, include a narrower portion with a width of from 2.5 mm to 6 mm, e.g. from 3 mm to 5 mm.
In one embodiment, for each elongate body the first wire receiving slot is defined between a first elongate outer wall and the first elongate edge, and the second wire receiving slot is defined between a second elongate outer wall and the second elongate edge.
It may be that for each elongate body the first elongate outer wall is 0.3 mm to 1 mm thick, e.g. about 0.5 mm thick, and the second elongate outer wall is 0.3 mm to 1 mm thick, e.g. about 0.5 mm thick.
In one embodiment, for each elongate body the first wire receiving slot may be from 1 mm to 2 mm wide, e.g. about 1.6 mm wide and may be from 5 mm to 10 mm long, e.g. about 8 mm long. For each elongate body the second wire receiving slot may be from 1 mm to 2 mm wide, e.g. about 1.6 mm wide and may be from 5 mm to 10 mm long, e.g. about 8 mm long.
In one embodiment, for each elongate body the first wire receiving slot extends substantially parallel to the elongate axis of the elongate body. In one embodiment, for each elongate body the second wire receiving slot extends substantially parallel to the elongate axis of the elongate body. However, it could be envisaged that the first wire receiving slot and/or the second wire receiving slot extends at an angle to the elongate axis of the elongate body, such as an angle of up to 30°.
For each elongate body, the blunt distal end may be any suitable shape but in one embodiment it is tapered, e.g. it may taper to a curved end.
In one embodiment, for each elongate body the closed end of the first wire receiving slot may be 2 mm to 10 mm or more from the distal end, e.g. from 3 mm to 8 mm from the distal end, such as about 5.2 mm from the distal end. In one embodiment, for each elongate body the closed end of the second wire receiving slot may be 2 mm to 10 mm or more from the distal end, e.g. from 3 mm to 8 mm from the distal end, such as about 5.2 mm from the distal end.
Suitably, each elongate body may be laser cut. However, the invention is not limited to use of this manufacturing technique.
Suitably, each elongate body may be formed from medical grade stainless steel, such as stainless steel 420 hardened. Medical grade stainless steel is known in the art.
The dimensions of the wires may be chosen by the skilled person. The invention is not limited to any particular size.
The medial cutting wire arc and the lateral cutting wire arc are suitably formed from wire with a diameter of from 0.5 to 1 mm, preferably 0.6 mm to 1 mm, e g. from 0.7 mm to 0.8 mm.
The length of the medial cutting wire arc is suitably from 50 to 100 mm, such as from 50 to 90 mm or from 50 mm to 80 mm, e.g. from 60 to 70 mm or from 80 to 90 mm. The length of the lateral cutting wire arc is suitably from 50 to 100 mm, such as from 50 to 90 mm or from 50 mm to 80 mm, e.g. from 60 to 70 mm or from 80 to 90 mm.
The wire to be used for the medial cutting wire arc and the lateral cutting wire arc must be strong and not brittle. It is therefore useful for the wire to be annealed, allowing it to be flexible. It may suitably be cable rope wire formed from stainless steel or titanium or titanium alloy. Medical grade stainless steel and titanium and titanium alloy wires are known in the art. Examples of suitable wire include Grade I titanium annealed and stainless steel annealed, e.g. stainless steel 321 annealed, or alternatively 1×19 strand 316 stainless steel (ss) or 1×19 strand 304 ss or DPD 189A ss. These have the strength and flexibility that is necessary to carry out the procedure. Any other wire having similar properties can be used.
It is envisaged that in one embodiment the wire to be used for one or both of the medial cutting wire arc and the lateral cutting wire arc is Gigli wire (e.g. with a diameter in the range of from 0.8 mm to 1 mm). Gigli wire may be chosen due its improved priorities in cutting through bone. In one embodiment, the wire for the medial cutting wire arc and the lateral cutting wire arc is Gigli wire. In another embodiment, the wire for the medial cutting wire arc is Gigli wire and the wire for the lateral cutting wire arc is titanium, e.g. Grade I titanium annealed.
The ends of the medial cutting wire arc and the lateral cutting wire arc are suitably secured in the respective receiving slots by laser welding. However, other techniques for securing the wires in the slots can be contemplated.
Suitably, each end of the medial cutting wire arc and the lateral cutting wire arc is crimped in a ferrule. Ferrule crimping is well known in the art.
In one embodiment, a ferrule is positioned in each respective wire receiving slot and a first portion of the length of the ferrule (at the closed end of the wire receiving slot) is welded in place. A second portion of the length of the ferrule (located at or extending from the open entrance of the wire receiving slot) is not welded and thus its lumen remains open. Therefore, each end of the cutting wire arc is fed into the lumen of a respective second portion of the ferrule and can then be crimped. Therefore, the ferrule is secured in the wire receiving slot by welding, and the wire is secured in the ferrule by crimping. The ferrule clearly should be sized such that at least the first portion of its length fits in the respective wire receiving slot.
In another embodiment, each end of the cutting wire arc is fed into a ferrule and crimped, and the ferrule is welded in place in its respective wire receiving slot. The ferrule clearly should be sized such that, when crimped, the flat surface of crimped ferrule fits in the respective wire receiving slot.
The length of the ferrule may be chosen by the skilled person. The invention is not limited to any particular size.
In one embodiment, the length of the ferrule may be from 10 to 20 mm long, especially from about 12 to 19 mm, e.g. from about 14 mm to 18 mm long, such as about 16 or 17 mm long. It may be convenient for the length of the ferrule to be long enough that a first portion of the ferrule length is used for welding the ferrule into place in the wire receiving slot and a second portion of the ferrule length is used for receiving the wire. For example, the first portion of the ferrule length may be from about 5 to 12 mm long (e.g. from about 7 to 11 mm) and the second portion of the ferrule length may be from about 5 to 12 mm long (e.g. from about 6 to 10 mm).
In another embodiment, the length of the ferrule may be from 6 to 12 mm long, e.g. about 8 mm to 9 mm long. It may be convenient for the length of the ferrule to be about 1 mm more than the length of the respective wire receiving slot. Each end of the cutting wire arc can then be fed into a ferrule and crimped, and the ferrule is welded in place in its respective wire receiving slot.
In one embodiment, the cutting wire has a diameter of 0.7 mm to 0.8 mm and the ferrule is 18 gauge, with an outer diameter of 1.27 mm and an inner diameter of 0.84 mm.
In one embodiment, the cutting wire has a diameter of 0.8 mm to 1 mm and the ferrule is 18 gauge, with an outer diameter of 1.27 mm and an inner diameter of 1.07 mm.
When using the first wire delivery device of the invention, the medial and lateral cutting wire arcs can be used to cut by:
If the implant is collared, it will be appreciated that the medial cutting wire arc must be located on the medial side of the implant in a position inferior to the collar, e.g. it may be hooked over the collar.
As noted above, in one preferred embodiment sub access tunnels have been formed for receiving the first and second elongate bodies, and therefore in one preferred embodiment the first and second elongate bodies are located in and pushed along these sub access tunnels.
The cutting wire arcs will not be directly exposed to the bone because they are secured in the wire receiving slots and these are spaced from the distal end. The distal end is therefore usefully blunt, to protect the bone from the wire. However, it is also envisaged that the distal ends of the first and second elongate bodies may be chisel like, e.g. with a 45 degree chisel angle. This can be advantageous in terms of facilitating an easy transition into the bone-implant interface. Also, it will assist with keeping the wire delivery device pushed against the implant.
The first and second elongate bodies are pushed in an alternating motion to cause the cutting wire arcs to cut, directing the force distally. As the medial cutting wire arc traverses distally, it will clear the bone-implant interface medially As the lateral cutting wire arc traverses distally, it will clear the bone-implant interface laterally. The distal movement of the first and second elongate bodies may be carried out manually, e.g., using a hammer, or a reciprocating mechanism (e.g. reciprocating saw) could be used to drive each of the first and second elongate bodies.
The first and second elongate bodies may, for example, be driven distally in an alternating motion 10 mm at a time until the tip of the device is at least 10 mm, preferably at least 30 mm, beyond the tip of implant. The first and second elongate bodies can suitably be driven distally using a hammer or power instruments e.g., a reciprocating saw-powered hand piece.
The implant will then be cleared of any bony ingrowth circumferentially around the implant. The implant is removed and then the wire delivery device can be removed.
In an alternative (second) embodiment, the novel wire delivery device of the invention comprises:
Each wire guidance channel is suitably located about 1 to 4 mm from the distal end. It may suitably be located substantially centrally in relation to the thickness of the plate but it may alternatively be off-centre. Each wire guidance channel may suitably have a depth of about 0.5 to 1.5 mm, or from 0.5 to 1 mm, e.g. about 0.7 mm or 0.8 mm; clearly the depth of the channel must be less than the depth (thickness) of the plate.
Each wire guidance channel runs from an entrance at the first elongate edge to an exit at the second elongate edge. If the channel is straight and runs perpendicular to the elongate axis of the elongate body, the length of the channel is the same as the distance between the first elongate edge and the second elongate edge (the width of the elongate body). However, it is also envisaged that the channel may be angled or curved or may comprise a combination of angled portions and/or curved portions and/or straight (perpendicular) portions. Therefore the length of the path travelled by the channel from the entrance to the exit may be greater than the width of the elongate body.
In relation to the wire guidance channel, the use of straight edges perpendicular to the elongate axis of the elongate body can be beneficial in terms of ease of manufacture. The use of angles (provided that these are not right angles) and/or curves can be beneficial in terms of reducing the risk of damage to the wire. It may be preferred that right angles are avoided, to reduce the risk of damage to the wire.
Each wire guidance channel may suitably have a height of from about 0.5 mm to 4 mm, such as 1 mm to 4 mm, e.g. about 2 mm.
The mouth portion that provides access to the wire guidance channel from the inner face or outer face must have a height that is at least equal to the diameter of the wire, so that the wire can be fed through the mouth portion into the wire guidance channel. In one embodiment, each mouth portion may have a height of from 0.5 mm to 1.5 mm or from 0.5 mm to 1 mm, e.g. about 0.6 mm or 0.7 mm or 0.8 mm.
Each mouth portion may be straight or may be curved or angled or combinations thereof. It may be straight and run perpendicular to the elongate axis of the elongate body. It may be angled or curved or may comprise a combination of angled portions and/or curved portions and/or straight (perpendicular) portions.
The use of straight edges perpendicular to the elongate axis of the elongate body can be beneficial in terms of ease of manufacture. The use of angles (provided that these are not right angles) and/or curves can be beneficial in terms of reducing the risk of damage to the wire.
Each engagement protrusion may be any suitable shape. It may, for example, be a shape that has straight edges, such as rectangular or square, or it may be a shape with angled edges, such as a triangle or a truncated triangle, or it may be a shape with curved edges, such as a tongue shape. It may include combinations of straight edges and/or, angled edges and/or curved edges. Each engagement protrusion may extend for part or all the distance from the first elongate edge to the second elongate edge. In one embodiment it extends across only part of width of the elongate body and is located substantially centrally between the first elongate edge and the second elongate edge. In another embodiment it extends across the full width of the elongate body.
In one embodiment, each channel is straight and runs perpendicular to the elongate axis of the elongate body. It may be that each mouth portion is also straight and runs substantially perpendicular to the elongate axis of the elongate body. Each mouth portion may, therefore, be rectangular in shape. Each corresponding engagement protrusion may also be a shape with straight edges and may have an edge that runs substantially perpendicular to the elongate axis of the elongate body. Each corresponding engagement protrusion may, therefore, be rectangular in shape and can be considered as a rectangular overhang. Each corresponding engagement protrusion may extend for part or all the distance from the first elongate edge to the second elongate edge; in one embodiment it extends across the full width of the elongate body. This design is beneficial in terms of case of manufacture.
In another embodiment, each channel is curved or includes a curved portion; it may, for example, include a “U” shape or a circular shape or other curved shape. It may be that each mouth portion is curved and may, for example, include a “U” shape or a Major arc or other curved shape. In one embodiment the “U” shape or Major arc or other curved shape is located substantially centrally between the first elongate edge and the second elongate edge. Each corresponding engagement protrusion may also be (or comprise) a curved shape and may, for example, be a tongue shaped overhang. Each corresponding engagement protrusion may extend for part or all the distance from the first elongate edge to the second elongate edge; in one embodiment it extends across only part of width of the elongate body and is located substantially centrally between the first elongate edge and the second elongate edge. This design is beneficial in terms of reducing the risk of damage to the wire.
In general, allowing the wire to lie in a curved channel means that there is smooth transference of loading of the wire as the instruments are driven down.
In another embodiment, each channel is angled or includes an angled portion; it may, for example, include a “V” shape or other angled shape. It may be that each mouth portion is angled and may, for example, include a “V” shape or other angled shape. In one embodiment the “V” shape or other angled shape is located substantially centrally between the first elongate edge and the second elongate edge. Each corresponding engagement protrusion may also be (or comprise) an angled shape and may, for example, be a triangular (or truncated triangular) shaped overhang. Each corresponding engagement protrusion may extend for part or all the distance from the first elongate edge to the second elongate edge; in one embodiment it extends across only part of width of the elongate body and is located substantially centrally between the first elongate edge and the second elongate edge.
In one embodiment, each channel includes a combination of curved and angled portions. In particular, it may be advantageous to have a central curved portion and an angled portion on each side of the central curved portion. It may be that each mouth portion includes a combination of curved and angled portions, e.g. a substantially central “U” shape or Major arc or other curved shape and an angled portion on each side. Each corresponding engagement protrusion may also be (or comprise) a curved shape and may, for example, be a tongue shaped overhang. Each corresponding engagement protrusion may extend for part or all the distance from the first elongate edge to the second elongate edge; in one embodiment it extends across only part of width of the elongate body and is located substantially centrally between the first elongate edge and the second elongate edge. This design is beneficial in terms of reducing the risk of damage to the wire.
Using a curved and/or angled configuration (without any right angles) reduces the risk of the wire being damaged, especially at the entry and exit points to the channel.
It will be appreciated that a range of shapes and sizes for each mouth portion and corresponding engagement protrusion could be used and that what is most important is that the wire can fit through the mouth portion to be fed into the wire guidance channel but that the wire can then engage with, and be secured in place by, the engagement protrusion.
Due to the fact that, in use, the wire delivery device will be pushed in the direction of the distal ends of the elongate bodies, it is preferred that the mouth portion is closer to the distal end than the engagement protrusion. This will facilitate the engagement protrusion keeping the wire in place during use.
The wire delivery device of the invention may suitably be provided together with a wire loop, although it will be appreciated that the user may obtain a wire loop independently.
The wire delivery device of the invention may be provided together with two or more wire loops (e.g. three or more wire loops) of different sizes and/or different materials to allow the user to select a suitable size or material. In particular, different size loops may be beneficial to allow the user to select a circumference of wire loop that fits over the implant in question. For example, circumferences of 70 mm, 85 mm and 100 mm could be provided.
In other words, there may be a wire delivery kit provided, comprising the wire delivery device of the invention together with one or more wire loop.
In general, the wire loop may have a circumference in the range of from 60 to 120 mm, such as from 70 to 100 mm. The wire loop is suitably provided in a form where it is already in a loop shape, but it may be that the loop is formed in situ. The user is capable of securing a wire into a loop shape when desired.
In one embodiment, the wire delivery device of the invention is provided with the wire loop already located and secured in the first and second wire guidance channels, so that the wire loop provides a medial cutting wire arc from the exit of the first wire guidance channel to the entrance of the second wire guidance channel and provides a lateral cutting wire arc from the exit of the second wire guidance channel to the entrance of the first wire guidance channel.
However, it will be appreciated that this is not essential, and the wire loop can be provided in a free-standing form and can then be located and secured in the first and second wire guidance channels by the user when desired.
The wire to be used in the wire loop must be strong and not brittle. It may suitably be cable rope wire formed from stainless steel or titanium or titanium alloy. Medical grade stainless steel and titanium and titanium alloy wires are known in the art. Examples of suitable wire include 1×19 strand 316 stainless steel (ss) or 1×19 strand 304 ss or DPD 189A ss or Grade I titanium annealed. These have the strength and flexibility that is necessary to carry out the procedure.
It is envisaged that in one embodiment the wire to be used is Gigli wire (e.g. with a diameter in the range of from 0.8 mm to 1 mm). Gigli wire may be chosen due its improved priorities in cutting through bone.
The cable rope wire may be 0.5 to 1.5 mm diameter, e.g. 0.8 to 1.5 mm diameter or 0.5 to 1 mm diameter. The thickness should be chosen taking into account the size and shape of the mouth portion and engagement protrusion because the wire must be able to fit through the mouth portion but also be secured in the channel by the engagement protrusion.
The wire loop is suitably formed by bringing together the two end sections of a length of medical grade wire and then crimping them to form a closed circle (wire loop). One or more metal ferrule may be used to enclose the two end sections before then crimping. Ferrule crimping is well known in the art.
If a single ferrule is used to enclose the two end sections, then the diameter of the ferrule used to crimp the ends should be such that it allows both ends of wire to slide past each other and protrude slightly on either side of the ferrule. Preferably, when crimped, the flat surface of crimped ferrule fits tightly proximally and distally and also medially and laterally in the wire guidance channel.
In one embodiment, in use, the crimped ferrule is located in a wire guidance channel. This assists with stability as the cutting action takes place and prevents the wire itself being damaged at the entry and exit points of the wire guidance channel during use. This is a suitable arrangement when the wire guidance channel is straight.
In one such embodiment, a second metal ferrule is provided on the wire loop, at a location diametrically opposite from the ferrule used for crimping the ends together. This has the benefit that one ferrule can be located in each wire guidance channel. This assists with stability as the cutting action takes place and prevents the wire itself being damaged at the entry and exit points of the wire guidance channel during use.
In another embodiment, in use, the crimped ferrule is located on the lateral side of the implant, i.e. in a location where the surface of the implant has already been cleared. This ensures that on the medial side, where cutting is taking place, there is a full arc of cutting wire uninterrupted by ferrule material.
As an alternative to enclosing the two end sections in a single metal ferrule before then crimping, each end section can be placed in a separate metal ferrule, each is then crimped, and then the ferrules with the crimped wire can be laser welded together. This allows a smaller diameter ferrule to be used and so in turn presents a smaller overall diameter of the crimped wires, which can be useful for ease of movement when cutting into the cancellous bone.
In general, the invention is not limited to the nature of the wire or how the wire loop is formed. It is within the skilled person's ability to select a suitable wire and form it into a loop.
It is also possible to use more than one wire loop at a time or to provide a wire loop that has a double thickness of wire forming the closed circle. The limiting factor is that the wire loop or loops must be able to fit in the wire guidance channel. If each section of wire used has too small a diameter it will not be strong enough. If the wire guidance channel is made bigger, to accommodate a greater diameter of wire, then the walls defining this channel within the elongate body will need to be made thinner in order to still keep the elongate bodies an overall size that can fit down the access tunnels as formed. This will be detrimental to the strength of the apparatus.
The first mouth portion can be located on the inner face or outer face of the first elongate body, and the second mouth portion can be located on the inner face or outer face of the second elongate body. For ease of use it is preferred that the same configuration is used for both elongate bodies, i.e. either: (a) the first mouth portion is located on the inner face of the first elongate body and the second mouth portion is located on the inner face of the second elongate body or (b) the first mouth portion is located on the outer face of the first elongate body and the second mouth portion is located on the outer face of the second elongate body.
In one embodiment, the first mouth portion is located on the outer face of the first elongate body and the second mouth portion is located on the outer face of the second elongate body. This can be beneficial in that as the first and second elongate bodies are pushed down the tunnels, the wire is additionally secured in place by the tunnel walls.
When using the wire delivery device of the second embodiment, once the wire loop is located and secured in the first and second wire guidance channels, the wire loop can be used to cut by:
As noted above, in one preferred embodiment sub access tunnels have been formed for receiving the first and second elongate bodies, and therefore in one preferred embodiment the first and second elongate bodies are located in and pushed along these sub access tunnels.
The wire loop will not be directly exposed to the bone because it is secured in the wire guidance channels and these are spaced from the distal end. The distal end is therefore usefully blunt, to protect the bone from the wire. However, it is also envisaged that the distal ends of the first and second elongate bodies may be chisel like, e.g. with a 45 degree chisel angle. This can be advantageous in terms of facilitating an easy transition into the bone-implant interface. Also, it will assist with keeping the wire delivery device pushed against the implant.
The first and second elongate bodies are pushed in an alternating motion to cause the wire loop to cut, directing the force distally. As the wire traverses distally, it will clear the bone-implant interface medially. The distal movement of the first and second elongate bodies may be carried out manually, or a reciprocating mechanism could be used to drive each of the first and second elongate bodies.
The first and second elongate bodies may, for example, be driven distally in an alternating motion 10 mm at a time until the tip of the device is 10 mm beyond the tip of implant. The first and second elongate bodies can suitably be driven distally using a hammer or power instruments e.g. a reciprocating saw-powered hand piece.
In one embodiment, a universal handle is provided which can be used as a handle for two or more of the devices described above, except for the targeting device which it will be appreciated does not require a handle. The universal handle may comprise a body having one or more grip portions at its proximal end and an engagement recess, such as a slot, at its distal end. The engagement recess is sized and shaped to receive the proximal end of the devices described above, except for the targeting device. In this regard, it will be appreciated that said devices may each be provided with a proximal end having the same size and shape, e.g. a flat plate, and the engagement recess of the universal handle is sized and shaped to receive this proximal end. In one embodiment, all of the devices included in the kit apart from the targeting device have the same size and shape of distal end, and thus the universal handle can be used as the handle for all of these devices.
In one embodiment, the universal handle has a block shaped head. It may, for example, be a cube or a cuboid shape. This can facilitate the use of a hammer to apply distal force to a device (e.g. a curette device, a medial-lateral clearance device, a chevron chisel, or a wire delivery device) via the handle. It will be appreciated that the handle could also be configured to be used with a reciprocating saw in order to provide the distal force via the handle. A reciprocating saw could usefully be used to apply distal force to a medial-lateral clearance device, a chevron chisel, or a wire delivery device.
In one embodiment, 10-30 mm, e.g. about 20 mm, of the elongate length of the cutting tool is located in the handle, e.g. in the block shaped head.
In one embodiment, a brace sleeve is provided which can be used to provide structural support for the elongate body of any of the devices described above, except for the targeting device which it will be appreciated does not have an elongate body. The brace sleeve may comprise two elongate faces which are joined at one elongate edge and are open at the opposite elongate edge and at the two ends, so as to create an elongate cavity between the two faces within which an elongate body can be received. The brace sleeve can slide onto and over an elongate body to provide additional strength and resistance to bending during use. The brace sleeve can cover some, most or all of the length of an elongate body of any of the devices described above.
One or more brace sleeve can alternatively or additionally be used to provide structural support for a handle located at the proximal end of the elongate body. One or more brace sleeves of different lengths can be used.
As noted above, in one embodiment, a hammer is used to apply distal force to a device (e.g. a curette device, a medial-lateral clearance device, a chevron chisel, or a wire delivery device) via the handle. In such embodiments, the universal handle may have a block shaped head; it may, for example, be a cube or a cuboid shape. The use of one or more brace sleeves on the handle is particularly beneficial in such embodiments, as it reduces the likelihood of the device bending on hammering the device to apply distal force.
In some embodiments there is a brace sleeve that extends over the boundary between the handle and the elongate body. This boundary can otherwise be a potential point of weakness. Therefore it can be beneficial to include a brace that covers some, most or all of the length of an elongate body of any of the devices described above and covers some, most or all of the length of handle attached to said elongate body.
In one embodiment, therefore, the brace sleeve is attached to the handle and is attached to the elongate body.
It may be that a set of brace sleeves of different lengths is provided. The brace sleeve that is initially used can then be exchanged for a shorter brace sleeve as the tool moves distally inside the patient's body, and thus the length of cutting tool that remains outside the patient's body gets shorter.
In one embodiment, for example, a brace sleeve of a first length (e.g. 185 mm long) can be attached to provide support for the handle and elongate body of a cutting tool. The tool can be hammered in distally until the exposed length of the cutting tool (e.g. 50-55 mm of cutting tool) has been hammered in. Then the brace is removed. A second brace sleeve having a second (shorter) length (e.g. 130 mm long) can then be attached to provide support for the handle and elongate body of the cutting tool. The tool can be hammered in distally until the exposed length of the cutting tool (e.g. 50-55 mm of cutting tool) has been hammered in. Then the brace is removed. A third brace sleeve having a third (shorter) length (e.g. 70 mm long) can then be attached to provide support for the handle and elongate body of the cutting tool.
The invention will now be further described with reference to the drawings, which are exemplary of the invention rather than limiting, and in which:
Various embodiments of the wire delivery device 400, 1400 of the invention are shown in
The device has a first elongate body 401, 1401 that extends from a first elongate edge 402, 1402 to a second elongate edge 403, 1403 and that has an inner face 404, 1404 and an outer face 405, 1405. The elongate body has a proximal end 406, 1406 that can be provided with a handle and a distal end 407, 1407 that is blunt or that may be sharp.
There is also second elongate body 421, 1421 that extends from a first elongate edge 422, 1422 to a second elongate edge 423, 1423 and that has an inner face 424, 1424 and an outer face 425, 1425. The elongate body has a proximal end 426, 1426 that can be provided with a handle and a distal end 427, 1427 that is blunt or that may be sharp.
In the first embodiment, as shown in
The first elongate body 1401 is provided with a first wire receiving slot 1408a and a second wire receiving slot 1408b. The first wire receiving slot 1408a is provided in a spaced relationship with the distal end 1407 and it is located towards the first elongate edge 1402. The first wire receiving slot 1408a runs from an open entrance to a closed end. The second wire receiving slot 1408b is provided in a spaced relationship with the distal end 1407 and it is located towards the second elongate edge 1403. The second wire receiving slot 1408b runs from an open entrance to a closed end.
The second elongate body 1421 is provided with a first wire receiving slot 1428a and a second wire receiving slot 1428b. The first wire receiving slot 1428a is provided in a spaced relationship with the distal end 1427 and it is located towards the first elongate edge 1422. The first wire receiving slot 1428a runs from an open entrance to a closed end. The second wire receiving slot 1428b is provided in a spaced relationship with the distal end 1427 and it is located towards the second elongate edge 1423. The second wire receiving slot 1428b runs from an open entrance to a closed end.
Each elongate body includes a tapered portion 1435 near to the location where the wire receiving slots are provided.
For each elongate body the first wire receiving slot 1408a, 1428a is defined between a first elongate outer wall and the first elongate edge, and the second wire receiving slot 1408b, 1428b is defined between a second elongate outer wall and the second elongate edge.
There is a first length of cutting wire 1413a having its first end secured in the first wire receiving slot 1408a of the first elongate body and having its second end secured in the first wire receiving slot 1428a of the second elongate body.
There is a second length of cutting wire 1413b having its first end secured in the second wire receiving slot 1408b of the first elongate body and having its second end secured in the second wire receiving slot 1428b of the second elongate body.
Each end of the medial cutting wire 1413a and the lateral cutting wire 1413b is crimped in a ferrule 1440 and is laser welded into its respective wire receiving slot.
In the configuration shown in
In the alternative configuration shown in
In the alternative configuration shown in
Likewise, whilst in the configuration shown in
In the first embodiment, as shown in
In the second embodiment, as shown in
There is a first wire guidance channel 408 provided in a spaced relationship with the distal end 407 and located within the first elongate body 401. The first wire guidance channel runs from an entrance 409 at the first elongate edge to an exit 410 at the second elongate edge.
Either the outer face 405 (embodiments of
There is a second wire guidance channel 428 provided in a spaced relationship with the distal end 427 and located within the second elongate body. The second wire guidance channel runs from an entrance 429 at the first elongate edge to an exit 430 at the second elongate edge.
Either the outer face 425 (embodiments of
The embodiment of
The embodiment of
In all the embodiments shown in
The universal handle 800 that can be used in the invention is shown in
The universal handle 800 is provided with a locking cap 804 which fits over the distal end of the body 801 and permits the enlarged head of the handle to be locked in place in the engagement recess 803. The locking cap 804 is provided with a dual slot 805, comprising a first elongate shaped slot 805a that can receive the enlarged head and allow it to pass therethrough, and a second elongate shaped slot 805b that can receive the neck and allow it to pass therethrough but that is too small to allow the enlarged head to pass therethrough. The first elongate shaped slot and the second elongate shaped slot overlap, with the elongate axis of the first elongate shaped slot being at an angle to the elongate axis of the second elongate shaped slot. Therefore the locking cap 804 can be placed over the distal end of the body with the first elongate shaped slot 805a aligned with the engagement recess and the enlarged head can pass through the first elongate shaped slot and into the engagement recess. Then the locking cap can be rotated such that the second elongate shaped slot 805b is aligned with the engagement recess, meaning that the enlarged head is locked into the engagement recess because it is too big to pass through the second elongate shaped slot. When it is desired to release the universal handle from the device, the locking cap can be rotated until the first elongate shaped slot is aligned with the engagement recess again.
The locking cap is spring loaded to assist with release. Therefore a torsion spring 806 is provided between the body 801 and the locking cap 804, which biases the locking cap away from the body.
The user can overcome that biasing force by pushing the locking cap onto the body. The locking cap can be held in place by the use of a securing means 807 (e.g. a locking pin and corresponding aperture) that connects the locking cap and the body.
The curette device that can be used in the invention is shown in
The curette device of the invention comprises an elongate body 200 in the form of a flat plate that extends from a first elongate edge 201 to a second elongate edge 202 and having a proximal end 203 that can be provided with a handle 203a and having a distal end 204 that is blunt. The handle 203a can be understood to have an enlarged head portion extending from a neck.
The curette device of the invention also comprises a first cutting portion 205 located at or near the distal end 204. This extends outwardly from the first elongate edge 201 of the elongate body. The cutting portion has a blunt edge 206 and a cutting edge 207 which meet at an angled cutting point 208. The blunt edge extends from a first location on the elongate body to the cutting point and the cutting edge extends from a second location on the elongate body to the cutting point, wherein the first location is closer to the distal end than the second location. Furthermore, the cutting edge is at an angle to the elongate axis of the curette device of from 50 to 85 degrees.
The curette device further comprises a second cutting portion 209, located between the second elongate edge 202 and the distal end 204 of the elongate body. In the embodiment illustrated, the second cutting portion 209 is provided on a curved edge that extends between the second elongate edge 202 and the distal end 204 of the elongate body. The second cutting portion is shown as comprising teeth, but alternatively or additionally, the second cutting portion may comprise a sharp edge.
Thus the curette device can be located in an access tunnel, with its elongate axis substantially aligned with the central axis running along the length of the tunnel, and with the distal end located at or near the distal (closed) end of the access tunnel, and then can be moved such that its elongate axis is angled with respect to the central axis running along the length of the tunnel, until the cutting edge contacts bony ingrowth located between the implant and the femoral cortex, and such that the curette device can then be withdrawn from the access tunnel whilst being retained in an angled position, such that as the device is withdrawn the cutting edge cuts away bony ingrowth located between the implant and the femoral cortex.
In the embodiment of
The elongate body 950 has a proximal end 953 that can be provided with a handle 954. The handle 954 can be understood to have an enlarged head portion extending from a neck.
The elongate body 950 has a distal end 955. A cutting portion is located at the distal end 955. The cutting portion comprises a first cutting face 956 and a second cutting face 957 which meet at an angled cutting point 958. The angled cutting point is located substantially centrally between the first elongate edge and the second elongate edge.
The first cutting face 956 extends at an angle of about 30 or about 45 degrees or about 60 degrees from the first elongate edge 951 when measured with respect to the elongate axis of the elongate body, and the second cutting face 957 extends at an angle of about 30 or about 45 degrees or about 60 degrees from the second elongate edge 952 when measured with respect to the elongate axis of the elongate body. In addition, the first cutting face 956 extends at an angle of about 30 or about 45 degrees or about 60 degrees from the lower face to the upper face, and the second cutting face 957 extends at an angle of about 30 or about 45 degrees or about 60 degrees from the lower face to the upper face.
The chevron chisel may optionally have a depth (the lower face to the upper face) of from 0.5 to 3 mm, e.g. 1 to 2 mm; it may be about 1 mm deep. The chevron chisel may optionally have a width (first elongate edge to a second elongate edge) of from 4 to 10 mm, e.g. 5 to 9 mm; it may be about 7 to 8 mm wide.
Embodiments of the targeting device that can be used in the invention are shown in
The targeting device comprises an anterior guide member 1. This comprises a first elongate body provided with a first angled channel 2 therein, running from an entrance 2a at the proximal end of the guide member to an exit 2b at the distal end of the guide member. The first angled channel is at an angle in the range of from 1 to 3 degrees to the elongate axis of the elongate body, ideally 2 degrees or 2.5 degrees or 3 degrees.
The first elongate body also has a first contact element in the form of a leg 3 at its distal end for contacting the shoulder of the femoral implant and for distancing the exit from the shoulder of the implant.
The targeting device also comprises a posterior guide member 4, which comprises a second elongate body provided with a second angled channel 5 therein, running from an entrance 5a at the proximal end of the guide member to an exit 5b at the distal end of the guide member. The second angled channel is at an angle in the range of from 1 to 3 degrees to the elongate axis of the elongate body, ideally 2 degrees or 2.5 degrees or 3 degrees.
The posterior elongate body also has a second contact element in the form of a leg 6 at its distal end for contacting the surface of the shoulder of the implant and for distancing the exit from the shoulder of the implant.
In some embodiments, there is one angled channel 2 with entrance 2a in the anterior guide member and one angled channel 5 with entrance 5a in the posterior guide member. For example, the angled channels may each have a rectangular cross section. This is shown in
In some embodiments, there are two angled channels 2 with entrance 2a in the anterior guide member and two angled channels 5 with entrance 5a in the posterior guide member. For example, the angled channels may each have a circular cross section. The angled channels in the anterior guide member may be co-joined and the angled channels in the posterior guide member may be co-joined. This is shown in
In some embodiments, there are three angled channels 2 with entrance 2a in the anterior guide member and three angled channels 5 with entrance 5a in the posterior guide member. For example, there may be one channel having a rectangular cross section and two having a circular cross section in each of the anterior guide member and the posterior guide member. The angled channels in the anterior guide member may be co-joined and the angled channels in the posterior guide member may be co-joined. This is shown in
The targeting device may optionally also include receiving channels 2c, 5c, for receiving the anterior guide member interlocking component 705 and the posterior guide member interlocking component 706 of the external targeting device as shown in
In this embodiment, the targeting device includes a first receiving channel 2c adjacent to the first angled channel 2 and aligned therewith and includes a second receiving channel 5c adjacent to the second angled channel 5 and aligned therewith. The anterior guide member interlocking component 705 and the posterior guide member interlocking component 706 are then received in these channels respectively. The first and second receiving channels 2c, 5c are shown as circular in cross section and these may each have a diameter of from 2 to 4 mm, such as about 3 mm. However, other shapes could be envisaged, e.g. they could have a square cross section, and likewise other sizes could be envisaged. The first and second receiving channels 2c, 5c may be blind channels and may, for example, extend for a depth of from 25 to 40 mm, such as about 30 mm.
The targeting device also comprises an engagement member 7 for locating and engaging the targeting device on the shoulder of the implant. This comprises an elongate body with an engagement protrusion 8 at its distal end. The engagement protrusion 8 can be received in a recess portion R on the shoulder of the implant. The elongate body of the engagement member can be located between and aligned with the elongate body of the anterior guide member 1 and the elongate body of the posterior guide member 4, such that the elongate axes of the elongate bodies are substantially aligned, and with the angled channels 2, 5 converging in the direction of the distal end, ideally at a convergence angle of 4 to 6 degrees, e.g. 4 degrees or 6 degrees.
The elongate body of the engagement member 7 may be substantially block-shaped. It may be that the block includes a rod 14 extending therethrough, with the distal end of the rod providing the engagement protrusion 8 (see
In one embodiment, the targeting device comprises a first pair of parallel connector rails 509, 510, which comprises one proximal rail 509 and one distal rail 510 (see
The connector rails are slidably secured to the engagement member. Therefore the proximal connector rail 509 is received in proximal connection bores in the anterior guide member, in the engagement member, and in the posterior guide member, whilst the distal connector rail 510 is received in distal connection bores in the anterior guide member, in the engagement member, and in the posterior guide member (see
In yet another embodiment, the targeting device comprises a first pair of parallel connector rails 609, 610, which comprises one proximal rail 609 and one distal rail 610, and a second pair of parallel connector rails 611, 612, which comprises one medial rail 611 and one lateral rail 612 (see
The first pair of parallel connector rails 609, 610 is located at or near the midpoint between the medial face of the guide members and the lateral face of the guide members. The second pair of parallel connector rails 611, 612 is located at or near the midpoint between the proximal end of the guide members and the distal end of the guide members.
The connector rails are slidably secured to the engagement member. Therefore the proximal connector rail 609 is received in proximal connection bores in the anterior guide member, in the engagement member, and in the posterior guide member, whilst the distal connector rail 610 is received in distal connection bores in the anterior guide member, in the engagement member, and in the posterior guide member (see
As shown in
The targeting device also comprises an adjustment system, which may be a double ended screw 13 that can adjust the distance between the elongate body of the anterior guide member 1 and the elongate body of the engagement member 7, so as to move the anterior guide member between a release position and a holding position and can simultaneously adjust the distance between the elongate body of the posterior guide member 4 and the elongate body of the engagement member 7, so as to move the posterior guide member between a release position and a holding position.
The double ended screw 13 can be received in a first engaging bore 13a in the anterior guide member, a second engaging bore 13c in the posterior guide member and a non-engaging bore 13b in the engagement member.
In the embodiment shown in
In the embodiment shown in
The double ended screw 13 does not engage with the non-engaging bore 13b in the engagement member. The non-threaded section in the middle of the double ended screw will be located in the non-engaging bore. Therefore the double ended screw extends through the engagement member but is not attached to the engagement member.
The double ended screw 13 does engage with the engaging bore 13a in the posterior guide member and does engage with the engaging bore 13c in the anterior guide member. The threaded portions at the two ends of the double ended screw are received in and engage with these engaging bores 13a, 13c. Therefore in use the double ended screw is attached to the anterior guide member and to the posterior guide member.
A key 600 may be provided that has a distal end 600a which engages with and rotates the double ended screw 13 (see
The use of a double ended screw means that the anterior guide member 1 and the posterior guide member 4 can be simultaneously moved closer to or away from the engagement member 7 by the same distance.
Therefore when the anterior guide member and the posterior guide member are connected by the connector rails, via the engagement member, the elongate axes of the elongate bodies are substantially aligned and the angled channels converge in the direction of the distal end, such that the engagement protrusion can be located in a recess portion on the shoulder of the implant, with the anterior guide member and the posterior guide member in their release positions, and then the adjustment member can be used to move the anterior guide member towards its holding position until the first contact element contacts the surface of the shoulder of the implant, with the exit of the first angled channel lying spaced from the implant, and to simultaneously move the posterior guide member towards its holding position until the second contact element contacts the surface of the shoulder of the implant, with the exit of the second angled channel lying spaced from the implant.
The angled channel in the anterior guide member may be an integral part of the guide member. In other words, the angled channel is fixed within the anterior guide member. Likewise, the angled channel in the posterior guide member may be an integral part of the guide member. In other words, the angled channel is fixed within the posterior guide member.
The targeting device may be used in combination with a medial targeting device 700, as shown in
When a medial targeting device 700 is used, the targeting device is provided with an alignment slot 517 located at the proximal end of the engagement member 7 (See
The medial targeting device 700 is in the form of a plate, which has an enlarged head 700a at the proximal end and an elongate body 700b that extends to the distal end. The enlarged head 700a is circular and is sized and shaped to be received in the alignment slot 517 of the engagement member 7 (see
In use (see
The side extension device 2000 can be formed from a side plate 2001 (e.g., 1 mm thick 420 hardened stainless steel) which is welded to a block 2002 (e.g., 5 mm thick 420 hardened stainless steel). The side plate 2001 suitably extends 20 mm beyond the welded block 2002.
The block 2002 includes an angled cut out 2003, so as to provide a 45-degree angled surface.
The block 2002 optionally also includes two holes 2004 on its inner face 2002a. As described below, these are required if the side extension device 2000 is to be used in combination with a central extension device. The holes 2004 are inclined 6 degrees distally.
The side extension device 2000 is available in a right-handed and a left-handed configuration.
Both the right-handed and left-handed side extension devices 2000 can be hammered into the femur at the bone implant interface at the shoulder of the implant, such that the side plates 2001 rest on the anterior and posterior aspects of the top of the shoulder of the implant respectively.
The targeting device can then be placed on top of the right-handed and left-handed side extension devices 2000, so that it is still positioned on the femur, but in an elevated manner due to the extra height provided by the two blocks 2002.
The cut out 2003 is positioned lateral to the implant, such that angled channel of the targeting device is lying in line with it.
The targeting device is then clamped tight onto the side extension devices 2000.
As noted above, the side plates 2001 rest on the anterior and posterior aspects of the top of the shoulder of the implant respectively. Thus, it will be appreciated that when a pair of right-handed and left-handed side extension devices 2000 are used, these create a width between their respective side plates 2001 that is determined by the dimensions of the implant below. The targeting device must be able to be positioned onto the side extension devices 2000 and therefore the width between their respective side plates 2001 cannot exceed the maximum opening dimension between the contact elements (legs 3 and 6) on the targeting device (20 mm).
Therefore, for larger implants, a different solution is used. In this regard, a central extension device 2500 is used in combination with one of the side extension devices 2000. The central extension device 2500 is shown in
The central extension device 2500 comprises a block 2501 having a side face 2502 from which two lugs 2503 project. The two lugs 2503 are shaped and sized so that they can be received in the respective two holes 2004 on the side extension device 2000.
The central extension device 2500 can therefore be attached to a side extension device 2000 by insertion of the two lugs 2503 into the two holes 2004 in the side extension device.
The side extension device 2000 should be chosen as being left-handed or right-handed based on which side of the implant is most easily accessible.
The side extension device 2000 plus attached central extension device 2500 can be positioned by inserting the side plate 2001 on the most accessible side, by hammering into the femur at the bone implant interface at the shoulder of the implant, as before.
Due to the holes 2004 in the side extension device 2000 being inclined 6 degrees distally, when the side extension device 2000 and central extension device 2500 are attached together, the anterior surface of the side extension device 2000 and the posterior surface of the central extension device 2500 will converge by 6 degrees. In other words, the holes 2004 will be pointing downwards by 6 degrees and thus when the two lugs 2503 of the central extension device 2500 are engaged into the holes 2004 a 6 degree convergence can be achieved.
The targeting device can then be placed on top of the side extension device 2000 and the central extension device 2500, so that it is still positioned on the femur, but in an elevated manner due to the extra height provided by the block 2002 and the block 2501.
The targeting device is then clamped tight onto the side extension device 2000 and the central extension device 2500.
The medial targeting device 700 (
An external targeting device of the invention is shown in
The targeting device interlocking portion 701 comprises a planar support body 704 provided with an anterior guide member interlocking component 705 and a posterior guide member interlocking component 706.
The anterior guide member interlocking component 705 comprises a first locking pin that extends from the planar support body in the same plane and can be received in the first angled channel. The posterior guide member interlocking component 706 comprises a second locking pin that extends from the planar support body in the same plane and can be received in the second angled channel. The location of the posterior guide member interlocking component 706 is fixed. A channel 707 is provided in the planar support body and the anterior guide member interlocking component 705 is provided with an engaging pin 708 that engages with and can slideably move along the channel and can be secured at any location therein. Thus the distance between the anterior guide member interlocking component 705 and the posterior guide member interlocking component 706 can be varied.
The alignment portion 702 comprises a planar elongate body 702a having an angled tip 702b at the distal end. The holding arrangement comprises a pivot nut, a pivot washer, and a locking screw that can be rotated from an open position where pivoting can occur to a locked position where pivoting is prevented. The holding arrangement therefore holds the planar elongate body and the planar support body in the same plane, but permits the pivotal movement of the planar elongate body relative to the planar support body within that plane.
In use, the first locking pin can be received in the first angled channel of the targeting device, and the second locking pin can be received in second angled channel of the targeting device, such that the planar support body is aligned with the anterior-posterior plane in which the first and second angled channels lie, and such that the planar elongate body is consequently also aligned with the anterior-posterior plane in which the first and second angled channels lie, such that the planar elongate body can be pivoted relative to the planar support body until the angled tip is alongside the implant and the plane of the angled tip can be compared to the centreline in the anterior-posterior plane, as determined via x-ray.
If the plane of the angled tip is not aligned with the centreline in the anterior-posterior plane, the location of the targeting device can be adjusted until the angled tip does align with the centreline in the anterior-posterior plane.
The brace targeting device 3000 provides an alternative way to create access tunnels anteriorly and posteriorly, using a chevron chisel 3708 (such as the chevron chisel shown in
The brace targeting device 3000 comprises a targeting device interlocking portion 3701, an alignment portion 3702, and a holding arrangement 3703 for holding and pivoting the alignment portion 3702 relative to the targeting device interlocking portion 3701. A brace sleeve 3707 is releasably connected to the targeting device interlocking portion 3701.
The targeting device interlocking portion 3701 comprises a planar support body 3704 provided at its distal end with an interlocking component 3705.
The interlocking component 3705 engages and locks with engagement component 3706. The engagement component 3706 is fixedly attached to brace sleeve 3707. The interlocking component 3705 and the engagement component 3706 provide the releasable connection between the brace sleeve 3707 and the targeting device interlocking portion 3701.
The alignment portion 3702 comprises a planar elongate body 3702a having an angled tip 3702b at the distal end.
The holding arrangement 3703 comprises a pivot nut, a pivot washer, and a locking screw that can be rotated from an open position where pivoting can occur to a locked position where pivoting is prevented. The holding arrangement 3703 therefore holds the planar elongate body and the planar support body in the same plane, but permits the pivotal movement of the planar elongate body relative to the planar support body within that plane.
The brace sleeve 3707 is suitably a spring-loaded brace sleeve as described in relation to
The elongate cavity of the brace sleeve 3707 is slightly wider than width of the chevron chisel that it is intended to be used with. The elongate cavity of the brace sleeve 3707 may suitably have a depth of 1.2 mm to 1.5 mm to allow easy passage of the chevron chisel whilst stopping distortion of the chevron chisel.
The engagement component 3706 is fixedly attached to the brace sleeve 3707, e.g. by welding. The engagement component is suitably an open-ended box (e.g. 20 mm to 30 mm in length) that can slidably receive the interlocking component 3705. The engagement component 3706 has an elongate axis that is aligned with the elongate axis of the cavity of the brace sleeve 3707.
The interlocking component 3705 is suitably a rectangular cross section solid bar that is slightly smaller in cross-section than the open-ended box engagement component 3706. Thus the solid bar interlocking component 3705 can be slid into the open-ended box engagement component 3706 and pushed until there is secure engagement.
In use, a chisel or osteotome is used (ideally 1 mm thickness) to clear a 1 mm to 2 mm deep space at the bone-implant interface from the shoulder of the implant, along the central sagittal axis of the implant.
The brace sleeve 3707 is provided in a form where it has been released from the targeting device interlocking portion 3701. A chevron chisel 3708, such as the chevron chisel shown in
The chevron chisel is then engaged into the space that has already been created between the implant and femur. The chevron chisel is aligned in the sagittal axis of the femur.
The brace sleeve 3707 is then secured to the targeting device interlocking portion 3701 of the brace targeting device 3000 by sliding the solid bar interlocking component 3705 into the open-ended box engagement component 3706 and pushing until there is secure engagement.
The planar elongate body 3702a having an angled tip 3702b is used to align the trajectory of the chevron chisel in the brace sleeve. In this regard, the chevron chisel is hammered distally into the bone implant interface, keeping the trajectory true by making sure the angled tip 3702b always remains in the middle of the medio-lateral diameter of the femur.
The chevron chisel is advanced to just beyond the distal tip of the implant, thus creating an access tunnel. The chevron chisel is left in situ and the brace targeting device 3000, including the brace sleeve 3707, is removed.
A second chevron chisel can then be inserted into brace sleeve 3707 and secured therein by the spring-loading mechanism, as before.
Using the chevron chisel already in situ as a line of sight, the second chevron chisel is hammered in on the other side of the implant to create a second access tunnel.
Both the chevron chisels are then removed, and the surgical procedure is carried out further as described previously, with use of the hook curette, medial-lateral clearance device (optional) and wire delivery device.
It will be appreciated from the above discussion in the context of using the brace targeting device 3000 to provide and position a chevron chisel (which has an elongate body) that any other device with a similar size elongate body could also be provided and positioned using the brace targeting device.
In particular, it is envisaged that the brace targeting device 3000 can be used with a wire delivery device of the invention, e.g., a device 1400 according to the first embodiment as shown in
The planar elongate body 3702a of the targeting device, having angled tip 3702b, can be used to align the trajectory of the elongate body 1401, 1421, in the brace sleeve. In this regard, the elongate body can be hammered distally, keeping the trajectory true by making sure the angled tip 3702b always remains in the middle of the medio-lateral diameter of the femur.
It will be appreciated that only one of the two elongate bodies of the wire delivery device needs to be secured inside the elongate cavity of the brace sleeve 3707; the second elongate body is attached to the first elongate body via the medial and lateral cutting wire arcs and can be positioned using the first elongate body as a line of sight.
The medial-lateral clearance device that can be used in the invention is shown in
The medial-lateral clearance device comprises an elongate body 300 having a proximal end 301 that can be provided with a handle 301a and having a distal end 302 that is blunt or may be sharp. If it is sharp, it may for example be a chevron shape. The elongate body is in the shape of a flat plate that extends from a first elongate edge 303 to a second elongate edge 304. The handle 301a can be understood to have an enlarged head portion extending from a neck.
In the embodiment of
The medial-lateral clearance device of the invention also comprises a cutting portion 305 extending outwardly from the elongate body and located at or near the distal end 302. The cutting portion has an inner surface 306 that is flat and which connects with the first elongate edge of the elongate body at a substantially 90 degree angle. In
The cutting portion has an outer surface 307 that comprises an angled cutting face 308 that is located towards the distal end of the elongate body. The inner surface meets the angled cutting face at a cutting edge 309, at an angle of from 20 to 70 degrees. This provides a sharp and chisel shaped end.
Thus the distal end of the flat plate elongate body can be located in a space at the bone-implant interface, at or near to the shoulder portion of the implant, with the flat plate being parallel to either the anterior surface or the posterior surface, and with the flat inner surface of the cutting portion aligned with either the medial or lateral surface of the implant, such that the medial-lateral clearance device can then be pushed in the direction of the distal end of the implant, with the flat plate elongate body remaining alongside the respective anterior or posterior surface, in the space at the bone-implant interface, whilst the angled cutting face cuts away bony ingrowth located at said medial or lateral surface of the implant as the device is pushed towards the distal end of the implant.
It will be appreciated that a pair of such medial-lateral clearance devices should be provided: one where the flat plate cutting portion is 90 to 110 degrees clockwise from the flat plate elongate body and one where the flat plate cutting portion is 90 to 100 degrees anticlockwise from the flat plate elongate body.
In addition, for both the “left handed” version and the “right handed” version, two or more different sizes may be provided.
A brace sleeve 750 that can be used in the invention is shown in
The brace sleeve 750 comprises two elongate faces 751, 752 which are joined at one elongate edge 753 and are open at the opposite elongate edge and at both the two ends, so as to create an elongate cavity between the two faces within which an elongate body can be slidably received. The brace sleeve can slide onto and over an elongate body to provide additional strength and resistance to bending during use. The brace sleeve can cover some, most or all of the length of an elongate body of any of the devices described above.
The two elongate faces may be flat and parallel to one another. However, in the illustrated embodiment, one of the elongate faces 752 flares outwardly towards the open elongate edge. This can assist with ease of placing the brace sleeve onto the elongate body, because it means that the open “mouth” of the brace sleeve is larger than the closed edge.
The brace sleeve 1750 comprises two elongate faces 1751, 1752 which are joined at one elongate edge 1753 and are open at the opposite elongate edge and at both the two ends, so as to create an elongate cavity between the two faces within which an elongate body can be slidably received.
The brace sleeve can slide onto and over an elongate body to provide additional strength and resistance to bending during use. The brace sleeve can cover some, most or all of the length of an elongate body of any of the devices described above.
The two elongate faces may be flat and parallel to one another, as illustrated.
The brace sleeve 1750 is provided with a securing system in which ball bearings 1754 (e.g. four ball bearings) are provided under a flat spring (e.g. a flat steel spring). This provides a spring-loaded effect, such that when an elongate body is placed inside the elongate cavity, it is clamped in place.
The brace sleeve 1750 may be provided in different lengths, e.g. there may be an 80 mm length and a 140 mm length version.
The width of the cavity may, for example, be from 1.3 mm to 1.9 mm, e.g. 1.5 mm; this can be chosen to suit the thickness of the elongate body to be received.
The ball bearings may have a diameter of 3 mm to 5 mm, e.g., about 4 mm. The flat spring may, for example, be about 0.5 mm thick.
The ball bearing and spring arrangement holds the elongate body, e.g. the elongate body of a chevron chisel inside the brace sleeve, and stops the brace sleeve coming away from the device when the brace is not held by the surgeon.
A brace sleeve 1850 may alternatively be provided in multiple sections, e.g. two or three or four sections, as shown in
In this illustrated embodiment there are three brace sections 1850a, 1850b and 1850c, each of which may be, e.g. about 50 mm long. They each have an internal space sized for receiving an elongate body, such as the elongate body of a chevron chisel, inside the brace sleeve. For example, the internal space may measure about 1.4 mm×8.5 mm.
One or more of the brace sections 1850a may be provided with a spring locking mechanism, e.g. as shown and described in
In one embodiment, one of the brace sections 1850c may be provided adjacent to a brace targeting device, e.g. as shown and described in
All of the brace sections 1850a, 1850b and 1850c can be slid off the elongate body of any of the devices described above and shown in the preceding drawings, in a proximal direction. This can, for example, be carried out as the device is advanced into the bone-implant interface. Any universal handle would of course need to be removed before sliding the brace section off the elongate body.
A moulded brace support is also provided by the present invention. This brace support can be injection molded, which facilitates the use of medical grade plastics. The moulded brace support can be made from any suitable medical grade plastic. It will be appreciated that the plastic should be soft enough that it can form a foldable hinge.
The moulded brace support is designed to provide structural support for (a) the elongate body of any of the devices described above and shown in the preceding drawings, except for the targeting device which it will be appreciated does not have an elongate body; and (b) a brace targeting device, e.g. as shown and described in
The moulded brace support is shown in
The base portion 1952 is located centrally in the unfolded configuration as shown in
The base portion 1952 is provided with a pair of arms 1952a which together define a receiving portion 1952b in which a portion of the brace targeting device can be received. The cavity-defining portion 1953 is provided with a cut-out cavity 1956 within which an elongate body can be slidably received.
When the moulded brace support 1950 is in its folded configuration, as shown in
In the folded configuration, the cavity-defining portion 1953 is folded on top of the base portion 1952 using hinge 1954, and the locking portion 1951 is folded on top of cavity-defining portion 1953 using hinge 1955. The cavity 1956 is then located and defined between the cavity-defining portion 1953 and the base portion 1952. This cavity 1956 is an elongate cavity within which an elongate body, such as the elongate body of a chevron chisel, can be slidably received. The pair of arms 1952a define the receiving portion 1952b in which an upright portion of the brace targeting device can be slidably received.
The moulded brace support 1950 can therefore be folded and locked in place over an elongate body, as the elongate body of a chevron chisel, to provide additional strength and resistance to bending during use. The moulded brace support can cover some, most or all of the length of an elongate body of any of the devices described above. The moulded brace support also receives and supports the brace targeting device.
It will be appreciated that the brace targeting device may also have some of its component parts injection moulded; for example, the alignment portion 3702 (comprising planar elongate body 3702a having an angled tip 3702b at the distal end) can be injection moulded, e.g. from medical grade plastics. However, it is also envisaged that the brace targeting device is made entirely from metal, e.g. stainless steel.
| Number | Date | Country | |
|---|---|---|---|
| 63231867 | Aug 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/GB2022/052076 | Aug 2022 | WO |
| Child | 18437966 | US |
