A surgical JIG positioning system

Abstract

A SURGICAL JIG POSITIONING SYSTEM A surgical jig positioning system 100 comprising: a device 1 including an alignment mechanism 4, such as a plurality of slidable pins 8 each fixable in a defined set translation, for accurate positioning of the device 1 at a desired location and orientation on a bone surface 12; and a bracket 50 removably securable to the device 1 and comprising a planar portion 76 disposed along a predetermined plane relative to the device 1 when secured thereto for defining a cutting plane 200 through the bone surface 12 and for receiving a cutting slot 84 of a surgical jig 80 thereby to align the cutting slot 84 with the cutting plane 200.

Description

A SURGICAL JIG POSITIONING SYSTEM

[0001] This invention relates to a surgical jig positioning system for use as an attachment on a device to scan a bone surface.BACKGROUND

[0002] Orthopaedic implants such as joint replacements require the implant to be fixed in a precise position and orientation in order to function correctly, and to have good longevity. While experience and a pre-clinical plan can help a surgeon correctly perform a bone cut or hole or position the implant, precise positioning is not always possible, particularly where the surgeon does not have any further guidance whilst they are operating and must make a subjective assessment on where to position the implant. This approach can result in implant failure, and as the revision rate for total knee replacement is approximately 7%, in which more than 10% of the implant failure is due to malalignment of the implant, this causes considerable discomfort to the patient. In severe cases this requires revision surgery which results in further cost, inconvenience and discomfort for the patient.

[0003] It is known to use surgical jigs to guide surgical procedures, such as resection cuts or drilling of a bone. However, accurate positioning of such surgical jigs is difficult to achieve. Typically, a jig is positioned on a bone surface and is secured in position through surgical pins or screws inserted through corresponding securing holes through the jig and into the bone beneath. Different jigs may have different securing hole locations.

[0004] While 3D printed patient-specific instrumentation (PSI) - which may include patientspecific surgical jigs - computer navigation and robotic surgery are also options for positioning implants during surgery, both of these approaches are prohibitively expensive for the majority of hospitals. Furthermore, production of PSIs requires considerable experience to produce due to the need to generate a 3D model of the surgical site and the PSI from scan data. Further time and experience is also required to manufacture the PSI and the deliver the device to hospital. Often such scan data is obtained from a CT or MRI scan of the patient which is a further disadvantage of this approach.

[0005] One recent system to address some of these shortcomings, developed by the present inventors, is disclosed in WO2022 / 258956, the entire contents of which are incorporated herein by reference. The system disclosed in WO2022 / 258956 provides an attachment for use with a device to scan a surface, for example a bone surface, the attachment comprising: a first housing portion configured to releasably secure a device comprising a camera, a second housing portion connected to the first housing portion and having a wall defining an internal region of the second housing portion and an external regionof the second housing portion, and a plurality of pins slidably secured to the wall, each of the plurality of pins having a proximal end disposed in the internal region and a distal end disposed in the external region. Upon abutment of the distal end of each of the pins against a surface, the proximal end of each of the pins is configured to translate relative to the wall. When the device is secured to the first housing portion, the proximal ends of the plurality of pins are viewable by the camera.

[0006] Thus, the system of WO2022 / 258956 provides an accurate and cost-effective attachment for use with a device such as a smartphone to scan a surface. A smartphone typically includes one or more cameras, and / or one or more sensors (e.g. accelerometers, gyroscopes, lidar sensors), and / or one or more light sources, and so provides a single integrated device having hardware which enables the surgeon to scan the surface without needing other sensing aspects. The light source from the phone is able to illuminate the pins from within the housing, such that the camera can track the movement of the pins. When used in an operative setting to scan a bone surface, the attachment enables more accurate and efficient mapping and navigation of a surface in a considerably more cost- effective manner when compared to patient-specific instrumentation and traditional pre- surgical planning. A further advantage is the attachment can be used as part of existing surgical processes, and thus a surgeon does not need to learn additional techniques, contrary to use of surgical robots. Importantly, the attachment and mobile phone can function as a positioning system which helps a surgeon find a desired operating point quickly and accurately. Alternatively, when the system is used as a tomography system or a 3D contact scanner, it allows the user to obtain a 3D surface model of the bone without using a CT scanner.

[0007] Figures 1-3 illustrate aspects of the system of WO2022 / 258956. The system includes an attachment 1 and a mobile phone 2 contained within the attachment 1. The attachment 1 includes a phone case 3, a pin holder 4 and an ergonomic handle 5 between the phone case 3 and the pin holder 4 to aid a user’s grip of the system during use. The phone case 3, pin holder 4 and ergonomic handle 5 may be considered as different portions of a housing of the attachment 1. While an ergonomic handle 5 is disclosed, it would be apparent this was not essential to the function of the pin holder 4 or phone case 3 and may be omitted in some cases.

[0008] The camera 7 of the smartphone 2 is shown positioned over a viewing window of the phone case 3. This allows the camera to view an arrangement of pins 8 secured in the pin holder 4 through the viewing window. It is preferable that the camera can view the proximal ends 13 of the pins 8 for scanning the surface as will be explained below.

[0009] While a mobile phone 2, such as a smartphone, is illustrated, this is merely a particularly convenient example of a suitable device that could be used with the attachment 1 ; other devices having a camera and connected to a processor configured to process images obtained from the camera would also be suitable for use with the attachment. Similarly, while a phone case 3 is described, it would be apparent that any holder that can secure a device in the described manner would be suitable.

[0010] The pin holder 4 includes an arrangement of pins 8 arranged across a wall (not shown, but extending perpendicularly across the interior of the pin holder 4 relative to the pins), with the pins 8 having a proximal section located within an internal region of the pin holder 4 and a distal section external to the pin holder 4. The handle 5 connects the pin holder 4 to the phone case 3. Specifically, the handle 5 connects to the phone case 3 over the viewing window such that the pins 8 are visible to the camera through the handle 5. The direction in which the pins 8 translate can be considered as a sensing direction.

[0011] The pins 8 are secured to the wall and extend through the wall from the external region to the internal region. As the pins 8 are slidably secured to the wall, pressing the pins 8 against the distal femur 12 causes the pins 8 to translate further into the internal region of the pin holder 4. This translation within the pin holder 4 can then be observed by the camera to determine a corresponding distance at the position of the pin in the external region. The relative displacement between multiple pins 8, effectively scans the surface of the distal femur and can be used to derive the tomography of the bone surface 12. Pogo pins are suitable for use as the pins 8 of the attachment. The pogo pin has a proximal end 13, a distal end 14 and a spring, or similar resiliently deformable element, biased to urge the distal end 14 away from the proximal end 13. The distal end 14 is also shown having a rounded end for engaging the bony surface 14.

[0012] The pin holder 4 also includes a post 15 which may be shaped and sized for a particular bony surface 12. For example an attachment for use in spinal surgery may utilise a different post 15 compared to an attachment which is to be used in knee or hip or shoulder surgery. The attachment of WO2022 / 258956 is suitable for use in any primary skeletal surgery or orthopaedic surgery. The post 15 functions to position and / or orient the pin holder 4 in a known pose (i.e. position and orientation) relative to a distal end of the post 15. By removing one or more degrees of freedom of the attachment 1 , this reduces the effort, and consequently the uncertainty, in correctly positioning the pin holder 4. While an attachment 1 having a single post 15 is shown at the pin holder 4, two or more posts may be secured to a single attachment 1. The post 15 is also preferably releasably secured to the attachment 1 , for example via a threaded connection, to provide greater flexibility of the attachment 1 and its constituent components.

[0013] As the post 15 contacts the distal femur 12 at different positions across its surface, the tomography of the surface indicated by the pins 8 will change. The tomography indicated by the pins 8 will also be dependent on the orientation of the pin holder 4 and post 15 when the post 15 contacts the distal femur 12. Thus, by moving the system around the bone (or any other surface) at the same position or at different positions on the bone, a 3D model of the bone (or any other object) can be determined using the smartphone by capturing multiple continuous images of the pins 8.

[0014] This scanned tomography can then be compared with other pre-operative scans or 3D models obtained by other modalities, such as CT or MRI imaging, to provide “live” feedback to the user regarding the position and / or orientation of the attachment 1 in relation to the correct position determined in the pre-operative plan. Further relevant details are set out in WO2022 / 258956 but may not be material to the present invention.

[0015] WO2022 / 258956 discloses that once the pin holder 4 has been accurately positioned on the bony surface 12, the user is able to lock the pins 8 in position via a locking mechanism connected to the pin holder 4. The illustrated locking mechanism includes a locking key 16 arranged to slide a locking plate (not shown in Figs. 1-3 here, but extending internally across the interior of the pin holder, parallel to the wall through which the pins translate) into engagement with the pins 8 to lock the pins 8 in position. The pins 8 extend through respective slots formed in the locking plate and when the locking plate is in an unlocked position, the pins 8 are free to move relative to the locking plate. When the locking plate is moved to the locked position, the slots through which the pins 8 extend engage the pins 8 to lock the pins in position.

[0016] WO2022 / 258956 further discloses that once the pins 8 are locked in position, holes formed in the wall of the pin holder 4 may act as guide holes to guide further components to pre-determined positions on the bony surface 12. The pin holder 4, therefore, effectively becomes a patient-specific surgical guide which can be used to guide surgical devices, such as drill bits, to desired positions on the bony surface 12. However, the attachment 1 avoids the need and technical skill required to manufacture a customised patient-specific surgical guide, as the pins 8 can be locked in position once the attachment 1 is correctly positioned. A further advantage of the attachment 1 is the ability to separate the pin holder 4 from the phone case 3 and / or handle 5, as the pin holder 4 is releasably secured to the attachment 1. Once the pins 8 are locked in position, there may be no further need for the mobile phone 2 and / or handle 5 as the pin holder 4 has been guided to the correct position. As such, the surgeon can simply detach the phone case 3 from the handle 5 and / or pin holder 8 to improve access to the surgical site.

[0017] Whereas the system disclosed in WO2022 / 258956 may be suited to use as a patient-specific surgical guide for certain procedures, such as drilling into the bone surface, it is not suited for use in guiding a resection cut across the bone surface - which would typically be in a plane substantially perpendicular to the pins.

[0018] Accordingly, there is a need for a system for accurately and inexpensively positioning a surgical jig on a bone surface, particularly a surgical jig with a cutting slot for guiding a resection cut across the bone surface.

[0019] Moreover, since there is no single standard surgical jig, it would be beneficial to provide a universal system that can be used to position a number of different surgical jigs.BRIEF SUMMARY OF THE DISCLOSURE

[0020] Viewed from a first aspect, the present invention provides a surgical jig positioning system comprising: a device including an alignment mechanism for accurate positioning of the device at a desired location and orientation on a bone surface; and a bracket removably securable to the device and comprising a planar portion disposed along a predetermined plane relative to the device when secured thereto for defining a cutting plane through the bone surface and for receiving a cutting slot of a surgical jig thereby to align the cutting slot with the cutting plane.

[0021] Thus, the present invention provides an accurate and cost-effective, universal mechanism for positioning any surgical jig at a defined location and orientation to ensure that the cutting slot thereof is aligned with a desired cutting plane.

[0022] The bracket may include a resiliently deflectable member for snap-fit gripping engagement with a corresponding portion of the device. The corresponding portion of the device may comprise a boss including a slot therein into which the resiliently deflectable member is received.

[0023] In certain embodiments, the bracket may include a clip member and a spacer member. The clip member may include a central boss with a slot defined therein, and the resiliently deflectable member may comprise a pair of resiliently deflectable arms extending from the central boss for a snap-fit gripping engagement around the device. The device may include an outer housing having a groove defined therein, and wherein the resiliently deflectable arms are received in the groove when engaged around the device. In other embodiments, the bracket comprises a unitary member, effectively comprising both the clip member and the spacer member as a single part.

[0024] The bracket (or, where comprising separate parts, specifically the spacer member) may include a tab, an arm extending at a defined angle from the tab, and said planar portion extending at a defined angle from the arm. The defined angle of the arm relative to the tab may be substantially perpendicular. The defined angle of the planar portion relative to the arm may be substantially perpendicular. Where the clip member includes a central boss with a slot defined therein, the spacer member may be removably engageable with the clip member through slidable insertion of the tab into the slot of the central boss.

[0025] The system may further comprise at least one additional bracket (or, where comprising separate parts, specifically at least one additional spacer member) defining a different predetermined plane of the planar portion thereof relative to the device. For example, the additional bracket(s) (or spacer member(s) thereof) may have arms of differing lengths and / or may include different defined angles between the arm and the tab and / or between the arm and the planar portion.

[0026] The alignment mechanism may include a plurality of slidable pins that can each be fixed in a defined set translation relative to the bone surface. An example of such an alignment mechanism is the pin holder of WO2022 / 258956.

[0027] The alignment mechanism may include at least one fixed alignment feature. An example of such a fixed alignment feature is the or each post of WO2022 / 258956.

[0028] There is also disclosed a kit comprising a surgical jig positioning system as described herein, and a surgical jig including a cutting slot for receipt on the planar portion of the bracket. Optionally, the kit may comprise multiple different brackets for defining different cutting planes relative to the device; and comprise multiple surgical jigs for different applications.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:Figures 1 & 2 illustrate side and back views of a known exemplary system for scanning and for attachment to a bone surface, engaged on the bone surface (here illustrated as the surface of a distal femur);Figure 3 illustrates a cross-sectional side view of the known exemplary system for scanning and for attachment to the bone surface (here also illustrated as the surface of a distal femur), disengaged therefrom;Figure 4 illustrates a side perspective view of an exemplary system according to a first embodiment, comprising a surgical jig positioning attachment in the form of a bracket portion, with surgical jig engaged therewith, as secured to a system for scanning and for attachment to a bone surface;Figure 5 illustrates individual elements of the exemplary system of Fig. 4: the surgical jig positioning attachment and associated clip, the surgical jig, and a detachable portion of the system for scanning and for attachment to a bone surface;Figure 6 illustrates the surgical jig positioning attachment and associated clip in assembled form;Figure 7 illustrates the surgical jig positioning attachment and associated clip in assembled form, together with the surgical jig;Figure 8 corresponds to a portion of Fig. 1 and illustrates the exemplary system of Fig. 4 in use to accurately position the surgical jig on the bone surface (here illustrated as the surface of a distal femur) for subsequent resection thereof;Figure 9 illustrates a side elevation view of an exemplary system according to a second embodiment, comprising a surgical jig positioning attachment, with surgical jig engaged therewith, as secured to a system for scanning and for attachment to a femoral bone surface;Figure 10 illustrates individual elements of the exemplary system of Fig. 9: the surgical jig positioning attachment in the form of a bracket portion, and the femoral surgical jig;Figure 11 illustrates individual elements of the exemplary system of Fig. 9: the bracket portion and a detachable portion of the system for scanning and for attachment to a bone surface;Figure 12 illustrates the surgical jig positioning attachment and associated bracket portion of the second embodiment in assembled form, together with the femoral surgical jig;Figure 13 corresponds to Figure 12, but showing the system in a first position at a surgical site (here illustrated as the anterior surface of a distal femur);Figure 14 corresponds to Figure 13, but showing the system in a second position at the surgical site, with the femoral surgical jig accurately positioned on the femoral bone surface (for subsequent resection thereof);Figure 15 corresponds to Figure 14, but from a perspective view;Figure 16 corresponds to Figures 14 and 15, from an alternative side elevation view and showing a drill bit being inserted through the femoral jig into the bone;Figure 17 depicts a third embodiment for application to a tibial bone surface, being an alternative configuration of the system of the second embodiment, and comprising an alternative bracket portion, and a tibial surgical jig;Figures 18A and 18B illustrate respective right- and left- hand versions of the bracket portion and associated tibial surgical jig;Figure 19 illustrates the system of Figure 17 in a first position at a surgical site (here illustrated as the surface of a proximal tibia), prior to positioning of the tibial surgical jig on to the bracket portion; andFigure 20 corresponds to Figure 19, but showing the system in a second position at the surgical site, with the tibial surgical jig accurately positioned on the tibial bone surface (for subsequent resection thereof).DETAILED DESCRIPTION

[0030] A surgical jig positioning system 100 according to a first embodiment is described and illustrated by reference to the accompanying figures 4 to 8. The system comprises a bracket portion 50 that is removably securable to an alignment mechanism 4 for accurate positioning of a device 1 at a desired location and orientation on a bone surface 12. In particular, the bracket portion 50 is for secure, removable attachment to the pin holder 4 of the system of WO2022 / 258956, which in turn is removably connected to the handle 5 and the phone case 3 with phone 2 within, as described above. The handle 5 may include an optional, removable portion 5b, located towards the pin holder portion for ergonomic gripping and manipulation of the system 100 by a user. Different removable portions 5b may be provided, for example having different sizes or shapes to better suit a particular user’s ergonomic requirements.

[0031] The bracket portion 50 comprises a clip member 60 formed of a central boss 62 from which extends a pair of resiliently deflectable arms 64 for a snap-fit gripping engagement around the pin holder 4. The arms 64 each have a profile substantially matching at least a respective portion of an outer surface of the pin holder 4. To aid in secure positioning and to prevent slippage, the arms 64 are preferably received in a corresponding grooved portion 4b of the outer surface of the pin holder 4. The clip member 60 may be removed from the snap-fit engagement by pulling the clip member 60 away from the pin holder 4 (or vice versa), thus urging the arms 64 to deflect to release. The centralboss 62 has an outwardly-facing slot 66. The clip member 50 may be formed of a plastic material.

[0032] The bracket portion 50 further comprises a spacer member 70, which includes a tab 72 for receipt in the slot 66 of the central boss 62 of the clip member 60, an arm 74 extending substantially perpendicularly from the tab 72, and a planar portion or plate 76 extending substantially perpendicularly from the arm 74 and thus parallel with and away from the tab 72. The tab 72 is slidable into and out of engagement with the slot 66 for attachment / release of the spacer member 70 to / from the clip member 60. It is typically a friction fit, although it will be understood that other releasable means of engagement are readily envisaged. As illustrated, the spacer member 70 is metal, formed by cutting and folding a sheet of stock material. It will be understood, however, that other materials and manufacturing techniques are also viable.

[0033] As best seen by reference to figure 8, the arrangement of the spacer member 70 when engaged with the clip member 60 and as attached to the pin holder 4 provides that the plate 76 is disposed along a defined plane 200 relative to the pin holder 4. Since, as described in WO2022 / 258956, the pins 8 can be fixed in position to define an accurate location of the pin holder on the bone surface 12, it can be assured that the defined plane 200 is thus accurately positioned relative to the bone surface. As explained more fully below, this is especially important for defining an accurate cutting plane for a resection cut through the bone surface. It will be understood that although the bracket portion 50 is described in the context of the specific system of WO2022 / 258956, that it could be applied to any alignment mechanism for accurate positioning of a device at a desired location and orientation on a bone surface.

[0034] The bracket portion 50 is used to position a surgical jig 80 at a desired location and orientation on the bone surface 12. In particular, a jig 80 comprising a body 82 through which is defined a cutting slot 84 may be received on the plate 76 of the spacer member 70 by sliding the cutting slot 84 on to the plate 76. This ensures that the cutting slot 84 is aligned with the desired cutting plane 200.

[0035] As illustrated, the cutting plane 200 is parallel to the base of the pin holder 4 and the clip member 60. The length of the arm 74 of the spacer member 70 defines how far beneath the pin holder 4 the cutting plane 200 will be positioned. Accordingly, different spacer members 70 having arms 74 of different lengths may be provided.

[0036] It will be appreciated that the cutting plane 200 could be oriented at other angles too, which would be defined by the angle of the plate 76 of the spacer member relative to the clip member 60. That differing angle may be achieved through providing different spacer members 70 having plates 76 at different angles relative to the associated arm 74, or byhaving the arms 74 at different angles relative to the associated tab 72, or a combination of the two. Alternatively or in combination, the differing angle could be achieved through a different angle of the slot 66 in the central boss 62 of the clip member 60, in which case different clip members 60 could be provided.

[0037] While the bracket portion 50 has been described as a two-part item, it will be understood that it could be formed as a unitary piece instead. It could be formed entirely from suitable plastic or metals, for example.

[0038] In use, a clinician would locate the pin holder 4 on the bone surface, for example through the defined positions of the pins 8 and other positioning aids as described by reference to WO2022 / 258956. The pin holder 4 is typically separated from the remainder of the system (the handle 5 and connected phone case 3 and phone 2) at this stage. The pin holder 4 may be temporarily fixed in position, for example by securing screws or pins passed through into the bone surface 12. The bracket portion 50 is attached to the pin holder 4, either before fixing the pin holder 4 in position or once it is fixed in place. The spacer member 70 may be attached to the clip portion 60 prior to attaching the clip portion to the pin holder 4 or once attached.

[0039] The surgical jig 80 is slid on to the plate 76 of the spacer member 70. Once in position, the jig 80 can be secured in the known manner through surgical pins or screws 90 inserted through corresponding securing holes 86 through the jig and into the bone 11 beneath (see figure 8). Numerous different jigs are available and there is no single, common design. Accordingly, different jig manufacturers might have different sizes of the surgical pins (or pin holes diameter) and differing dimensions between the cutting slot 84 and the surgical pin holes 86. Because the jig 80 is positioned by reference to its cutting slot 84, the present positioning system has universal application to any surgical jig with such a cutting slot 84.

[0040] With the jig 80 secured in position, the bracket portion 50 and the alignment mechanism (i.e. the pin holder 4) can be removed, either together as a unit or individually. This leaves just the surgical jig 80 in a fixed position at a defined location and orientation with the cutting slot 84 aligned with the desired cutting plane 200, so the clinician is free to proceed with a resection procedure by inserting a cutting device, such as a circular saw, through the cutting slot 84.

[0041] A surgical jig positioning system 100’ according to a second embodiment is described and illustrated by reference to the accompanying figures 9 to 20. The system 100’ is broadly similar to the system 100 of the first embodiment as described above, but has a differently configured bracket portion. The reference numbers for the bracket portionof the second embodiment will thus correspond to those of the first embodiment, but suffixed with a prime (’) as appropriate.

[0042] The system 100’ comprises a bracket portion 50’ that is removably securable to an alignment mechanism 4’ for accurate positioning of a device T at a desired location and orientation on a bone surface 12. The pin holder 4’ may be removably connected to the handle 5’ and the phone case 3’ with phone 2 within. The pin holder 4’ includes wings 4c projecting from opposed sides thereof for receiving bone screws 110 to secure the pin holder 4’ in position once aligned on the bone surface 12. The pin holder 4’ also includes a central boss 4d projecting from a forward side thereof and comprising a slot 4e for receiving the bracket portion 50’. As illustrated, the slot 4e comprises an inverted ‘II’ shape - having a horizontal top portion and a pair of vertical portions extending from opposed ends thereof. It will be understood that other shapes and configurations would be possible.

[0043] The bracket portion 50’ comprises an integrated clip and spacer member, which includes a tab 72’ for receipt in the slot 4e of the central boss 4d of the pin holder 4’ (specifically into the horizontal top portion of the slot), an arm 74’ extending substantially perpendicularly from the tab 72’, and a planar portion or plate 76’ extending substantially perpendicularly from the arm 74’ and thus parallel with and away from the tab 72’. A pair of resiliently deflectable arms 64’ extend rearwardly from the arm 74’ parallel to the tab 72’. The tab 72’ and resiliently deflectable arms 64’ are slidable into and out of engagement with the slot 4e for attachment / release of the integrated clip and spacer member 70’ to / from the pin holder 4’. The engagement is typically a friction fit between the tab 72’ and the slot 4e, with the resiliently deflectable arms 64’ providing a click-fit releasable engagement with the vertical portions of the slot 4e. Other releasable means of engagement are readily envisaged, however. The bracket portion 50’ may be removed from the snap-fit engagement by pulling away from the pin holder 4’ (or vice versa), thus urging the arms 64’ to deflect and overcoming the frictional engagement of the tab 72’ with the slot 4e to release. The bracket portion 50’ is metal, formed by cutting and folding a sheet of stock material. It will be understood, however, that other materials and manufacturing techniques are also viable.

[0044] Thus, rather than being removably attached to an exterior surface of the pin holder and comprising a two-part construction of separable clip and spacer members, the bracket portion 50’ of the second embodiment is a unitary piece that is removably attached to a boss on the pin holder 4’.

[0045] The bracket portion 50’ is used to position a surgical jig 80’ at a desired location and orientation on the bone surface 12. In the illustrated example of Figures 9 to 16 the surgical jig 80’ is a femoral jig for defining a resection cutting plane through the distal femoral bone surface. The jig 80’ comprises a body 82’ through which is defined a cutting slot 84’that may be received on the plate 76’ of the bracket portion 50’ by sliding the cutting slot 84’ on to the plate 76’, thus ensuring that the cutting slot 84’ is aligned with the desired cutting plane 200.

[0046] As illustrated, the cutting plane 200 is parallel to the base of the pin holder 4’ and the tab 72’. The length of the arm 74’ of the bracket portion 50’ defines how far beneath the pin holder 4’ the cutting plane 200 will be positioned. Accordingly, different bracket portions 50’ having arms 74’ of different lengths may be provided.

[0047] It will be appreciated that the cutting plane 200 could be oriented at other angles too, which would be defined by the angle of the plate 76’ relative to the tab 72’. That differing angle may be achieved through providing different bracket portions 50’ having plates 76’ at different angles relative to the associated arm 74’, or by having the arms 74’ at different angles relative to the associated tab 72’, or a combination of the two. Alternatively or in combination, the differing angle could be achieved through a different angle of the slot 4e in the central boss 4d of the pin holder 4’, in which case different pin holders 4’ could be provided.

[0048] Use of the system 100’ substantially corresponds to use of the system 100 as described by reference to Figure 8 above. The arrangement of the bracket portion 50’ when engaged with the pin holder 4’ provides that the plate 76’ is disposed along a defined plane 200 relative to the pin holder 4’, thereby defining an accurate location of the pin holder on the bone surface 12. As before, the pin holder 4’ is separable from the handle 5’ so that once the pin holder 4’ is secured in position e.g. by the screws 110, the handle 5‘ and attached phone holder 3’ and phone 2 can be taken away so as not to obscure vision of the site. The bracket portion 50’ is attached to the pin holder 4’, either before fixing the pin holder 4’ in position or once it is fixed in place.

[0049] The surgical jig 80’ is slid on to the plate 76’ of the bracket portion 50’. This may be done after the bracket portion 50’ has been secured in position (by virtue of its attachment to the pin holder 4’) so that the jig 80’ does not encumber that positioning or may be preattached. Once in position, the jig 80’ can be secured in the known manner through surgical pins or screws inserted through corresponding securing holes 86’ through the jig and into the bone 11 beneath. The bone 11 may first be drilled using a drill bit 150 (see Figure 16).

[0050] Numerous different jigs are available and there is no single, common design. Accordingly, different jig manufacturers might have different sizes of the surgical pins (or pin holes diameter) and differing dimensions between the cutting slot 84’ and the surgical pin holes 86’. Because the jig 80’ is positioned by reference to its cutting slot 84’, the present positioning system has universal application to any surgical jig with such a cutting slot 84’.

[0051] In the foregoing, the surgical jig 80; 80’ has been for alignment of a resection cut through a distal femoral bone surface. It will be understood that the invention has wider application to other surfaces. One example is the proximal tibial bone surface, and in particular for defining a resection cutting plane therethrough.

[0052] A surgical jig positioning system 100” according to a third embodiment and directed to such a tibial bone resection is described and illustrated by reference to the accompanying figures 17 to 20. The system 100” is broadly similar to the system 100’ of the second embodiment as described above, but has a different bracket portion 50” and the associated surgical jig 80” is specifically for alignment of a resection cut 300 through a proximal tibial bone surface. For brevity, like parts will not be described again. The reference numbers for the bracket portion 50” of the third embodiment will thus correspond to those of the second embodiment 50’, but suffixed with a double prime (") as appropriate.

[0053] The pin holder 4’ is identical to that of the second embodiment, and the upper part of the bracket portion 50” comprising the tab 72’ and’ resiliently deflectable arms 64” likewise corresponds, for removable attachment with the slot 4e of the boss 4d. However, rather than extending substantially perpendicularly from the tab and the end of the boss 4d all the way to the plate in a straight line, the arm 74” is kinked, bending back under the boss 4d with a series of bends so that at least a rear portion of the plate 76” is overlapping with the pin holder 4’. This enables the tibial jig 80” to be better positioned adjacent the tibial bone surface 112. Also, rather than a substantially rectangular plate 76; 76’, the plate 76” is profiled with curved edges to more closely correspond to the adjacent portion of the tibial bone surface. The tibial jig 80” has a matching profile. In each of Figures 17, 18A, 19 and 20, the tibial jig 80” and the corresponding bracket portion 50” are left-handed versions, for use on a patient’s left knee. It will be understood that symmetrical versions, for use on a patient’s right knee, can also be provided, as illustrated in Figure 18B.

[0054] As illustrated, the cutting plane 300 is parallel to the base of the pin holder 4’ and the tab 72”. The length of the arm 74” of the bracket portion 50” defines how far beneath the pin holder 4’ the cutting plane 300 will be positioned. Accordingly, different bracket portions 50” having arms 74” of different lengths may be provided.

[0055] It will be appreciated that the cutting plane 300 could be oriented at other angles too, which would be defined by the angle of the plate 76” relative to the tab 72”. That differing angle may be achieved through providing different bracket portions 50” having plates 76” at different angles relative to the associated arm 74”, or by having the kinked portions of the arms 74” at different angles, or a combination of the two. Alternatively or in combination, the differing angle could be achieved through a different angle of the slot 4e inthe central boss 4d of the pin holder 4’, in which case different pin holders 4’ could be provided.

[0056] With the jig 80’ or 80” secured in position, the bracket portion 50’ or 50” and the alignment mechanism (i.e. the pin holder 4’) can be removed, either together as a unit or individually. This leaves just the surgical jig 80’ or 80” in a fixed position at a defined location and orientation with the cutting slot 84’ or 84” aligned with the desired cutting plane 200 or 300. The clinician is then free to proceed with a resection procedure by inserting a cutting device, such as a circular saw, through the cutting slot 84’ or 84”.

[0057] Whereas the present system has been described primarily in the context of application to resection cuts on a femoral bone surface 12, or a tibial bone surface 112, as useful for hip or knee surgery, it will be understood that the system can be used more broadly for application to other bone surfaces, such as for use in shoulder or spinal surgery, for example.

[0058] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0059] Features, integers, characteristics, or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS1. A surgical jig positioning system comprising: a device including an alignment mechanism for accurate positioning of the device at a desired location and orientation on a bone surface; and a bracket removably securable to the device and comprising a planar portion disposed along a predetermined plane relative to the device when secured thereto for defining a cutting plane through the bone surface and for receiving a cutting slot of a surgical jig thereby to align the cutting slot with the cutting plane.

2. The surgical jig positioning system of claim 1, wherein the bracket includes a resiliently deflectable member for snap-fit gripping engagement with a corresponding portion of the device.

3. The surgical jig positioning system of claim 2, wherein the corresponding portion of the device comprises a boss including a slot therein into which the resiliently deflectable member is received.

4. The surgical jig positioning system of claim 1 or claim 2, wherein the bracket includes a clip member and a spacer member.

5. The surgical jig positioning system of claim 4, when dependent on claim 2, wherein the clip member includes a central boss with a slot defined therein, and the resiliently deflectable member comprises a pair of resiliently deflectable arms extending from the central boss for a snap-fit gripping engagement around the device.

6. The surgical jig positioning system of claim 5, wherein the device includes an outer housing having a groove defined therein, and wherein the resiliently deflectable arms are received in the groove when engaged around the device.

7. The surgical jig positioning system of any preceding claim, wherein the bracket includes a tab, an arm extending at a defined angle from the tab, and said planar portion extending at a defined angle from the arm.

8. The surgical jig positioning system of claim 7, wherein the defined angle of the arm relative to the tab is substantially perpendicular.

9. The surgical jig positioning system of claim 7 or claim 8, wherein the defined angle of the planar portion relative to the arm is substantially perpendicular.

10. The surgical jig positioning system of any of claims 7 to 9, when dependent on claim 5, wherein the spacer member is removably engageable with the clip member through slidable insertion of the tab into the slot of the central boss.

11. The surgical jig positioning system of any of claims 7 to 10, further comprising at least one additional bracket defining a different predetermined plane of the planar portion thereof relative to the device.

12. The surgical jig positioning system of any preceding claim, wherein the alignment mechanism includes a plurality of slidable pins that can each be fixed in a defined set translation relative to the bone surface.

13. The surgical jig positioning system of any preceding claim, wherein the alignment mechanism includes at least one fixed alignment feature.

14. A kit comprising: a surgical jig positioning system of any preceding claim; and a surgical jig including a cutting slot for receipt on the planar portion of the bracket.

15. The kit of claim 14, comprising multiple different brackets for defining different cutting planes relative to the device; and comprising multiple surgical jigs for different applications.

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