Device for aligning a guide wire with a bone

Abstract

A device for aligning a guide wire with a bone. The device comprises: at least one superior jaw configurable to contact a portion of the bone; at least two inferior jaws configurable to contact different portions of the bone; a guide member configurable to align a guide wire to the bone; wherein the positions of the at least one superior jaw, at least one of the at least two inferior jaws, and the guide member are independently adjustable.

Description

[0001] ALIGNMENT DEVICE

[0002] FIELD OF THE INVENTION

[0003] The present disclosure relates to an alignment device, in particular an alignment device for aligning a guide wire with a bone. The present disclosure also relates to a method of setting an alignment device for aligning a guide wire with a bone.

[0004] BACKGROUND TO THE INVENTION

[0005] During a hip resurfacing operation, the head of the femur is retained and capped with a head implant with a spherical bearing of a similar size to the natural joint. The bone socket in the pelvis is reamed to approximately a hemispherical shape and a thin walled cup implant is fitted to completely reline the hip joint with an artificial bearing.

[0006] In order to regain natural range of motion and to ensure the bearing functions well over a long period of time, it is very important to position both the head and cup implants correctly relative to the natural bone and soft tissue structures. This is particularly challenging in the diseased hip where the head of the femur is often misshapen and the acetabular socket has migrated slightly out of position. This can be misleading when it comes to positioning the implant components. Furthermore, the surgeon has limited access and visibility during the operation, so it can be difficult to visualise anatomical landmarks and to judge the orientation of the bones.

[0007] When the surgeon positions a resurfacing head implant on the femur bone the following factors are considered. Firstly, the femoral head / neck size is considered: The choice of head implant size should be approximately the same as the natural head size, at the same time there must be enough bone available on the head to support the implant fully and it is vital that the cutters used to prepare the head do not encroach into the femoral neck (known as notching) as it weakens the bone and can cause femoral neck fracture postoperatively. Second, the varus / valgus angle is considered: This is the angle between the femur shaft axis and the head implant axis and should be in the range 135 to 145 degrees so that the load is transferred through the implant without putting undue stress on the bone. Thirdly, the version angle is considered. This is the forward tilt angle of the femoral neck relative to the frontal anatomical plane. It is unique for each patient and usually within the range 15 to 25 degrees. The surgeon will try to place the head axis according to the natural femoral neck version angle for a specific patient.

[0008] Patient specific guides are sometimes used in joint replacement operations to help position implants. The guides are defined and constructed preoperatively based on three-dimensional digital images of the patient's joints. The digital images of the patient's joint can be reconstructed from medical scans of the patient using commercially available computer aided design (CAD) and / or other specific planning software. The surgeon or skilled technician interacts with the software to place the implants in the desired positions relative to the patient’s scanned bones. A patient matched guide is then defined and constructed using rapid prototyping techniques such as SLS additive manufacture. These guides are devised to fit exactly with a patients exposed bone surfaces intraoperatively so that the implants can be directed exactly to their planned positions.

[0009] An advantage of a patient specific head guide for the resurfacing head is that the femoral head / neck size, the varus / varus angle, and the version angle may be resolved simultaneously according to a pre-operative plan as the guide fits exactly into a distinct position on the femur bone. However, a disadvantage is that these patient specific head guides can take time to prepare following planning and before the operation date, typically one to two weeks minimum. Furthermore, these patent specific head guides may require significant extra cost.

[0010] Pre-operative planning using digital templating with x-rays may be used to determine implant sizes and approximate positions. However, implementation of the plan is only by sensory evaluation intra-operatively, for example by visual comparison of the actual guides and implants with a 2d plan displayed onscreen in the operating theatre. Thus, achieving appropriate implant sizes and positions to a suitable degree of accuracy is difficult.

[0011] The present disclosure has been devised to mitigate or overcome at least some of the above-mentioned problems.

[0012] SUMMARY OF THE DISCLOSURE In accordance with a first aspect of the present disclosure, there is provided a device for aligning a guide wire with a bone, said device comprising: at least one superior jaw configurable to contact a portion of the bone; at least two inferior jaws configurable to contact different portions of the bone; a guide member configurable to align the guide wire with the bone; wherein the positions of at least one of the at least two inferior jaws and the guide member, and optionally the at least one superior jaw, are independently adjustable.

[0013] The proposed device may provide a means for aligning a guide wire with a bone, for example a guide wire with a femur, with a degree of accuracy that is equivalent to patient specific head guides currently used. Advantageously, the proposed device may provide such a means for aligning the guide wire with the bone without the additional time, expense, and complex logistics required to prepare and use patient specific head guides.

[0014] Preferably, the at least one of the inferior jaws, and optionally the at least one superior jaw, are moveable with respect to a longitudinal axis of the device; the at least one superior jaw is moveable away from or towards the at least two inferior jaws; and the guide member is angularly adjustable. Accordingly, the jaws may be moved or adjusted according to patient-specific requirements, and the angle of the guide member can be adjusted so as to properly align the guide wire with the bone. Advantageously, any shape of bone maybe accommodated by the proposed device via adjustment of the components.

[0015] The device preferably further comprises a centring element for maintaining a central position of the guide member between the at least one superior jaw and the at least two inferior jaws. The centring element may advantageously facilitate positioning of the guide wire centrally within, for example, the femoral neck of a femur bone.

[0016] Preferably, the device further comprises a frame, wherein the frame comprises: a central body for supporting the guide member; a first side for supporting the at least one superior jaw; and a second side for supporting the at least two inferior jaws; wherein the first side and the second side are arranged to move in parallel with respect to one another, such that the at least one superior jaw can be displaced with respect to the at least two inferior jaws. The frame may provide a means for more easily adjusting the positions of each component. Furthermore, the frame may provide a rigid structure for supporting the components of the device, which may advantageously minimise positional deviations for each components.

[0017] In some embodiments, the parallel motion is provided by a displacement means arranged to move the first side and the second side with respect to one another. Advantageously, the at least one superior jaw may easily be separated or moved away from the at least two inferior jaws, thus making adjustment of the device according to specific patent requirements easier.

[0018] The frame preferably further provides the centring element for maintaining a central position of the guide member between the at least one superior jaw and the at least two inferior jaws. In particular, the displacement means preferably provides this centring element.

[0019] In some embodiments, the displacement means comprises a scissor clamp mechanism connecting the central body with the first side and the second side. The scissor clamp mechanism may advantageously provide a compact and smooth means for facilitating parallel motion of the at least one superior jaw and the at least two inferior jaws. The scissor clamp may additionally provide the centring element function, in which the central body (which supports the guide member) maintains a central position between the first side (which supports the at least one superior jaw), and the second side (which supports the at least two inferior jaws).

[0020] In some embodiments, the displacement means comprises a gear arrangement having a circular gear engaging first and second linear gears, wherein the circular gear is connected to the central body, the first linear gear is connected to the first side, and the second linear gear is connected to the second side. The gear arrangement may advantageously provide a means for separating the first side from the second side, whilst maintaining a central position of the central body. The displacement means may comprise more than one such gear arrangement to facilitate a secure connection between the central body, the first side, and the second side.

[0021] In some embodiments, the guide member is pivotally connected to the central body. Thus, an angle of the guide member with respect to the central body may easily be adjusted. By pivoting with respect to the central body, the angle of the guide member may more appropriately match up with an angle of insertion of the wire with respect to the bone.

[0022] In some embodiments, a pivoting centre of the guide member is projected to a virtual position, the virtual position located on a central axis of the central body. This projection of the pivoting centre of the guide member may be beneficial when soft tissue is present where the pivoting centre needs to be, particularly when the device is used in the anterior surgical approach.

[0023] While the at least one superior jaw can be fixed in respect of longitudinal movement, in some embodiments, the at least one superior jaw is slidably connected to the frame, such that the superior jaw can move along the longitudinal axis of the frame. Advantageously, the provision of a means for moving the at least one superior jaw along the longitudinal axis of the frame may provide an extra degree of freedom for altering the position of the at least one superior jaw. In particular, the at least one superior jaw may be moved along the longitudinal axis via the slidable connection, and may also be moved along an axis perpendicular to the longitudinal axis via the displacement means.

[0024] In some embodiments, the at least one superior jaw connects to the frame via a first connection means, the at least two inferior jaws connect to the frame via a second connections means, and the first connection means is incompatible with the second connection means. In this way, the at least one superior jaw may be connected to the frame at only the position of the frame in which the corresponding first connection means portion is located. In particular, since the first connection means is incompatible with the second connection means, the at least one superior jaw may not be connected to the frame at the second connection means. Similarly, the at least two inferior jaws may not be connected to the frame at the first connection means portion. This may advantageously facilitate faster assembly of the device in its correct arrangement, since the respective jaws may not be connected at points that are incompatible. Furthermore, assembly errors may be avoided and confusion may be reduced.

[0025] In some embodiments, the at least two inferior jaws comprise: a fixed jaw; and a moving jaw; wherein the moving jaw is slidably connected to the fixed jaw, such that the moving jaw can move relative to the fixed jaw. In this way, the at least two inferior jaws may be more easily positioned by sliding the moving jaw. Additionally, the at least two inferior jaws may require only a single connection point to the frame, thus improving the simplicity of the device. Furthermore, since only the moving jaw of the at least two inferior jaws is moved, the ease of set-up of the device is improved due to a reduction in setup parameters.

[0026] In some embodiments, the device further comprises a displacement gauge for determining a superior jaw position. Advantageously, the device may provide a means for more easily positioning the at least one superior jaw.

[0027] In some embodiments, the device further comprises a separation gauge for measuring a separation of the at least two inferior jaws. Advantageously, the device may provide a means for more easily positioning the at least two inferior jaws.

[0028] In some embodiments, the device further comprises an angular gauge for gauging an angle of the guide member with respect to a longitudinal axis of the device. Advantageously, the device may provide a means for more easily positioning the guide member.

[0029] In some embodiments, the device further comprises a locking means to prevent the jaws from moving away from the longitudinal axis of the device. Advantageously, the locking means may prevent the jaws from deviating from their intended or arranged positions once set.

[0030] In accordance with a second aspect of the present disclosure, there is provided a preoperative planning process for setting a device for aligning a guide wire with a bone, the process comprising the steps of: accessing image data of an image of said bone; identifying one or more positioning parameters based on the image data; and adjusting the device based on the one or more positioning parameters.

[0031] The pre-operative planning process may provide a means for determining an arrangement of the device ahead of use. The accuracy provided by such a process may be greater than existing digital templating processes, which require a visual comparison of the actual guides and implants with a 2d plan displayed onscreen in the operating theatre.

[0032] In some embodiments, identifying the one or more positioning parameters comprises: generating a digital template; superimposing the digital template over the image of said bone; determining a suitable position for the digital template; identifying one or more positioning points; and identifying the one or more positioning parameters based on the one or more positioning points. The digital template may advantageously provide a means for more easily determining the one or more positioning parameters.

[0033] In some embodiments, the digital template comprises an assistance overlay. The assistance overlay may provide assistance in determining the suitable position for the digital template. More particularly, the assistance overlay may convey the varus-valgus angle (or stem-shaft axis angle), which is an important angle for determining the suitable position of the digital template.

[0034] In some embodiments, identifying the one or more positioning parameters based on the one or more positioning points comprises: generating a second digital template; aligning the second digital template with the one or more positioning points; and identifying the one or more positioning parameters based on the position of the one or more positioning points with respect to the second digital template.

[0035] In some embodiments, the device is the device of the first aspect of the present disclosure. In some embodiments, the one or more positioning parameters comprise: an inferior jaw spacing; a superior jaw position; and a guide member angle. Thus, the proposed pre-operative planning process may be used to determine positions for the at least one superior jaw, the at least two inferior jaws, and the guide member of the device of the first aspect of the present disclosure. Advantageously, the device may be fully calibrated ahead of the procedure in which the guide wire is inserted into the bone.

[0036] It will be appreciated that any features described herein as being suitable for incorporation into one or more aspects or embodiments of the present disclosure are intended to be generalizable across any and all aspects and embodiments of the present disclosure. Other aspects of the present disclosure can be understood by those skilled in the art in light of the description, the claims, and the drawings of the present disclosure. The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claims.

[0037] BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0038] Figure 1 shows an isometric view of a head guide in accordance with a first aspect of the present disclosure;

[0039] Figure 2A shows a plan view of the head guide;

[0040] Figure 2B shows a plan view of the head guide in an alternative embodiment;

[0041] Figure 3 shows an exploded isometric view of the head guide with removable jaw subassemblies for both left and right hips;

[0042] Figure 4 shows an isometric view of the jaw sub-assemblies for a left hip via posterior approach;

[0043] Figure 5 shows an isometric view of the head guide with assembled jaw sub-assemblies for a left hip via posterior approach;

[0044] Figure 6 shows a frontal view of the head guide with assembled Jaw sub-assemblies;

[0045] Figure 7 shows an isometric view of the head guide assembled with jaw sub-assemblies clamped onto a right femur bone via a posterior approach;

[0046] Figure 8 shows a digital X-ray image with a resurfacing head template;

[0047] Figure 9 shows a digital X-ray image with the head template and 3 points added;

[0048] Figure 10 shows an additional template with scales and lines marked;

[0049] Figure 11 shows a digital X-ray image with both templates overlayed;

[0050] Figure 12 shows a digital X-ray image with both templates overlayed and an additional angle measurement; Figure 13 shows a digital X-ray image with the head template and various lines and measurements added;

[0051] Figure 14A shows a flow diagram of a pre-operative planning process for setting a device for aligning a guide wire with a bone, in accordance with a second aspect of the present disclosure; and

[0052] Figure 14B shows a flow diagram of sub-steps for identifying one or more positioning parameters.

[0053] Note that the drawings are schematic and accompany the description, illustrating preferred and exemplary embodiments and not necessarily being drawn to scale.

[0054] DETAILED DESCRIPTION

[0055] Head Guide

[0056] The present disclosure provides a device for aligning a guide wire with a bone.

[0057] Figure 1 shows an isometric view of the device, and more particularly a head guide 1 , in accordance with a first aspect of the present disclosure. Figure 2A shows a plan view of the head guide 1.

[0058] The head guide 1 comprises a frame having a central body 2, connected to a first side 3 and a second side 4.

[0059] The first side 3 and the second side 4 are arranged to move in parallel with respect to one another. The parallel action is provided by a displacement means arranged to move the first side 3 and the second side 4 with respect to one another.

[0060] The displacement means comprises a scissor clamp mechanism connecting the central body 2 with the first side 3 and the second side 4. The scissor clamp mechanism comprises a pair of tines 5; and a pair of cross members 6; wherein the tines 5 and the cross members 6 are arranged in a criss-cross pattern; and wherein the tines 5 are secured to the cross members 6 at a plurality of securing locations 7. At the securing locations 7, the pair of tines 5 are connected to the pair of cross members 6 via pins that facilitate pivoting of the tines 5 with respect to the cross members 6. There are eight securing locations 7 in the illustrated example.

[0061] To provide movement of the first side 3 and the second side 4 with respect to one another, the central body 2, the first side 3, and the second side 4 each comprise a slot 8 in which a respective pin 7 is located and guided. Pins 7 attached to the tines 5 occupy the slots 8 of the first side 3 and the second side 4, whilst a pin 7 attached to the cross members 6 occupies the slot 8 of the central body 2. The pins 7 traverse the guides 8 to allow for lengthening and shortening of the tines 5 and cross members 6 as the head guide 1 opens and closes. The displacement means thus allows for extension and contraction of the tines 5 and the cross members 6 along an axis. Notably, the first side 3 and the second side 4 remain parallel to the central body 2, and remain at an equal distance away from the central body 2.

[0062] An alternative displacement means is shown in Figure 2B, which shows a plan view of the head guide 1 in an alternative embodiment. The displacement means comprises a gear arrangement having a circular gear 101 engaging first 102 and second 103 linear gears, wherein the circular gear 101 is connected to the central body 2, the first linear gear 102 is connected to the first side 3, and the second linear gear is connected to the second side 4. Slots or undercuts 104 are provided in the first side 3 and second side 4 for receiving the opposing linear gears, such that a more compact configuration can be achieved.

[0063] A movement of one side, for example the first side 3 moving left in Figure 2B, causes a corresponding rotation of the circular gear 101 via engagement of the first linear gear 102 with the circular gear 101. Rotation of the circular gear 101 causes a corresponding, but opposite (i.e., to the right in the present example), movement of the second linear gear 103, thus providing separation of the first side with respect to the second side. Throughout said separation, the central body 2 maintains a central position between the first side 3 and the second side 4.

[0064] The displacement means comprises two such gear arrangements, a first being proximate a first end of the central body 2, and a second being proximate a second end of the central body 2. The head guide 1 further comprises a gripping means. The gripping means can allow the user to open and close the head guide 1 more easily. The gripping means comprises a loop 9, or pair of loops 9, each extending from distal ends of respective tines 5. Thus, the head guide 1 can be gripped like a pair of scissors, typically with forefinger and thumb occupying respective loops 10. The loops 9 comprise external tabs 10 for resting another finger for added stability.

[0065] The head guide 1 further comprises a locking means for locking the first side 3 and the second side 4 at a particular displacement. The locking means may comprise a ratchet arm 11 and a pawl 12. The ratchet arm 11 is pivotably attached to the first side 3, and engages with the pawl 12 attached to the second side 4 to hold the position of the sides when squeezed together with a finger grip. The ratchet arm 11 comprises an integral leaf spring 13 which biases the ratchet arm 11 to engage with the pawl 12, so the ratchet arm 11 engages and holds automatically as the head guide 1 closes. This enables the head guide 1 to be clamped around the femoral neck as will later be described. The ratchet arm 11 is released by pushing the ratchet arm 11 away from the pawl 12 against the light spring pressure provided by the leaf spring 13, and simultaneously opening the head guide 1 by extending the finger grip outwards.

[0066] The head guide 1 further comprises a guide member. In the present example, the guide member is a swing arm 16. The swing arm 16 is supported by the central body 2 via a securing means, such as securement screw 17. The swing arm 16 remains attached to central body 2 via undercuts 18 which engage with flanges 19 proximate a second end of the central body 2. The swing arm 16 moves in a rotating arc and can be locked in any position with the securement screw 17.

[0067] The head guide 1 further comprises an angular gauge for gauging an angle of the guide member (i.e., an angle of guide wire insertion) with respect to the longitudinal axis of the device. The central body 2 includes, proximate a first end of the central body 2, a protractor 15. The protractor 15 comprises a 90-degree angle marking in its central position, symmetrical increments, and 5 and 10 degrees markings away from the central position. The head guide 1 further comprises an angle indicator for clearly indicating the angle of insertion.

[0068] Typically, the swing arm 16 can be locked (e.g., via the securement screw 17) in 1- degree increments either side of the 90-degree central position. The protractor 15 comprises retaining means for preventing the swing arm 16 from disengaging fully from the protractor 15. The retaining means comprises one or more retaining pins 20. In the present example, the angle indicator is a visual indicator located on the swing arm 16. The visual indicator is a line or notch arranged to line up with an angular marking on the protractor 15.

[0069] The swing arm 16 comprises a guide tube 21 mounted below, and parallel to the swing arm 16. A drill guide 22 with a spiked end 23 fits through, and is accommodated by, the guide tube 21. In the 90-degree position, the drill guide 22 is parallel to, and centred between, the first side 3 and the second side 4.

[0070] As shown in Figure 2, due to mating curved surfaces 24 of the central body 2 and the swing arm 16, the pivoting centre of the swing arm 16 is projected to a virtual position 25 at the centre of curve radius 26. At this position, the axis 27 of the central body 2 and the axis 28 of the drill guide 22 coincide in all protractor positions. This position remains central between the 3-jaw grips as will be described later.

[0071] The head guide 1 further comprises a displacement gauge for gauging a superior jaw position. More particularly, the displacement gauge is for gauging a superior jaw position with respect to a longitudinal axis of the head guide 1. At least one of the first side 3 and the second side 4 comprises the displacement gauge. In the present embodiment, the first side 3 and the second side 4 both comprise the displacement gauge. In particular, the first side 3 and the second side 4 each comprise a letter scale 14 marked with letters A-L. The function of this letter scale 14 will become further apparent when the jaw subassemblies are attached as will later be described. Since both sides comprise the displacement gauge, superior jaws of differing orientation (e.g., for different surgical approaches and / or hip sides) are compatible with the head guide 1.

[0072] Before use of the head guide 1 for aligning a guide wire with a bone, jaw sub-assemblies are attached to the head guide 1.

[0073] Figure 3 shows an exploded isometric view of the head guide 1 with removable jaw subassemblies for both left and right hips. Figure 4 shows an isometric view of the jaw subassemblies for a left hip via posterior approach. Figure 5 shows an isometric view of the head guide 1 with assembled jaw sub-assemblies for a left hip via posterior approach. Figure 6 shows a frontal view of the head guide 1 with assembled Jaw sub-assemblies. As shown in figures 3 to 6, a pair of jaw sub-assemblies are attached to the head guide 1 before use. Depending on the surgical approach and the hip side being operated on, either one pair of jaw sub-assemblies or the other is used. Figure 3 shows both pairs of jaw sub-assemblies with dotted lines to show their locating positions on the head guide 1.

[0074] The jaw sub-assemblies are located in their respective locating positions via locating means. The locating means comprises a screw and corresponding screw receiver. For posterior surgical approach, a first jaw pair 29 is used for the left hip, and a second jaw pair 30 is used for the right hip. The anterior surgical approach is to the opposite side of the hip, and as such the second jaw pair 30 is used for left hip and the first jaw pair 29 is used for the right hip.

[0075] With reference to Figure 4, the first jaw pair 29 comprises: a superior jaw sub-assembly 32 marked ‘SUP’; and an inferior jaws sub-assembly 33 marked ‘INF’.

[0076] The superior jaw sub-assembly 32 comprises a single jaw 34. The jaw 34 comprises: a flat body section 37; and a curved grip section 38 extending away from the body section 37, for example at 90 degrees to the body section 37. When attached to the frame of the head guide 1 , the superior jaw sub-assembly 32 is supported by the first side 3 (or the second side 4, depending on the surgical approach). The superior jaw sub-assembly may slidably connect to the frame, such that the superior jaw can move relative to the frame (i.e. , along the longitudinal axis). In particular, the body section 37 may be slidably attached to the first side 3 of the head guide 1 via a screw captive in a slot 36, and corresponding screw thread located on the head guide 1. The grip section 38 is positioned so it grips onto the superior femoral neck in use.

[0077] The body section 37 comprises a position indicator for indicating a position on the head guide 1. In particular, the top surface of the body section 37 comprises a window 41 with a central mark, which indicates a position along the displacement gauge (i.e., the letter scale 14). The body section 37 also comprises a gripping means, such as a textured grip. The body section 37 also comprises a plus symbol 42 visual indicator.

[0078] The inferior jaw sub-assembly 33 comprises: a fixed jaw 43; and a moving jaw 44. Both jaws 43, 44 comprise: a flat body section 45; and a curved grip section 46 extending away from the body section 45, for example at 90 degrees to the body section 45. The moving jaw body section 45 is positioned on top of the fixed jaw body section 45.

[0079] The fixed jaw 43 and the moving jaw 44 are connected via a connection means. The moving jaw 44 is slidably connected to the fixed jaw 43, such that the moving jaw 44 can move relative to the fixed jaw 43. The connection means comprises a screw 47 which passes through a hole on the fixed jaw 43, and a slot 48 on the moving jaw 44. The fixed jaw body section 45 attaches to the frame of the head guide 1 and the two grip sections 46 are positioned so they grip around the inferior femoral neck in use. When attached to the head guide 1 the two grip sections 46 are aligned with one another, but the spacing between them is variable.

[0080] The head guide 1 comprises a separation gauge for measuring displacement of the moving jaw 44 with respect to the fixed jaw 43. For example, the fixed jaw 43 comprises a measurement scale 50 in millimetres. The body section 45 of the moving jaw 44 has a tapered end 52 where the measurement scale 50 can be read-off. A cut-away 53 of the body section 45 of the moving jaw 44 allows the dimension numerals to be seen clearly as the scale is read-off.

[0081] The top surface of the body section 45 of the moving jaw 44 has a textured grip. The measurement scale 50 directly indicates jaw grip spacing (distance between grip centres).

[0082] To avoid errors, the jaw sub-assemblies comprise indicators to ensure that the jaw subassemblies are assembled in their correct pairs. The indicator may comprise a visual indicator for recognition purposes. For example, the first jaw pair 29 comprise a triangle symbol, whilst the second jaw pair 30 comprise a circle symbol. These symbols are located on the respective screws in the present example.

[0083] Furthermore, to avoid errors, the jaw sub-assemblies comprise location indicators to ensure that the jaw sub-assemblies are assembled in their correct positions on the head guide 1. For example, two different connection means are used for each jaw subassembly of a pair of jaw sub-assemblies. In particular, using the first jaw pair 29 as an example, the superior jaw sub-assembly 32 connects to the frame via a first connection means, the inferior jaw sub-assembly 33 connects to the frame via a second connections means, and the first connection means is incompatible with the second connection means. More particularly, the first connection means comprises a screw 35 arranged to engage with a corresponding first female screw thread on the first side 3. The second connection means comprises a screw 47 arranged to engage with a corresponding second female screw thread on the second side 4. The female screw threads are dimensioned such that only corresponding screw threads can fit. Thus, the screw 35 is incompatible with the female screw thread of the second side 4, and vice versa, and the first jaw pair 29 can only be assembled in the correct positions, with jaw grip sections 38, 46 forming an inward facing circle. The screw 35 and first female screw thread are of a first size, for example M6, whilst the screw 47 and second female screw thread are of a second size, for example M8.

[0084] Figure 5 shows the head guide 1 with the first jaw pair 29 assembled. The superior jaw 32 is slidably adjustable on the second side 4 and can be locked in position by tightening the screw 35. The letter in the window 41 indicates the position it is set to (in this case position ‘E’).

[0085] The inferior fixed jaw 43 is in a fixed location but remains loose until the screw 47 is tightened. The moving jaw 44 is slidably adjustable to alter the spacing of the two inferior grip sections 46. The spacing distance between grip centres is indicated by the measurement scale 50. Both jaws are locked firmly in position by tightening the screw 47. The inferior jaw grips 46 remain in-line with one another and parallel to the central body 2 as they side through their range of adjustment.

[0086] Figure 6 shows that when viewed from the front, the drill guide axis 55 is centred relative to the grip section of the jaws 38, 46. This is the case in any position of opening and closing of the head guide 1 and in all adjustment positions.

[0087] Figure 7 shows the assembled head guide 1 clamped onto a femur bone 57, with the swing arm 16 positioned at 88 degrees (indicated by the angle indicator). The head guide 1 is clamped in a stable position with all three jaws 34, 43, 44 gripping around the femoral neck 58. A guide wire 59 is inserted into the drill guide 22 and partially drilled into the femur bone 57. As described above, the head guide 1 is set up so that the guide wire passes centrally into the femoral neck.

[0088] The gripping sections 38, 46 of all three jaws 34, 43, 44 are shaped such that they at least partially conform to the shape and / or angle of the bone when in position. Such a shaping assists in locating the implant on a natural angle. The skilled person will be aware of suitable shapes of the gripping sections to allow for configuration of the device along the angle of the bone. For example, the gripping sections may be crescent shaped and curving inwards, so that they grip around the approximately elliptical cross-section of the femoral neck. Further jaw shapes may be envisaged (e.g. V-shaped, U-shaped, etc.). The two inferior jaws 43, 44 are spaced apart so that they take-up the natural angle of the inferior femoral neck in the coronal (frontal) plane. In addition, the spaced apart jaws take up the natural version angle (slightly forward tilting angle) of the femoral neck relative to the coronal plane. The angle of guide wire insertion can be fine-tuned, so that:

[0089] • The 90-degree position of the angular gauging means is exactly aligned with the two inferior jaws 43, 44, and therefore also aligned with the inferior femoral neck.

[0090] • Up to 12 degrees above 90 degrees (plus side of scale) is in more valgus (or vertical) angle relative to the inferior femoral neck.

[0091] • Up to 12 degrees below 90 degrees (minus side of scale) is in more varus (or horizontal) angle relative to the inferior femoral neck.

[0092] In use, when the device is in position on the bone, it is important that the at least two inferior jaws both contact the bone. With the two inferior jaws in position on the bone, the angle for the axis of the head implant can be accurately set / fixed. The superior jaw effectively acts as an anchor, and can be positioned along any part of the bone on the opposite side of where the at least two inferior jaws are positioned. The parallel movement of the superior and inferior jaws towards each other to grip the bone ensures that each of the jaws is brought into contact with the bone at the desired position to ensure the angle of the guide member is correct.

[0093] Pre-operative Planning Process

[0094] The present disclosure also provides a pre-operative planning process for planning or determining jaw gripping positions for achieving a desired position of a head implant. Planning can be carried out either before or during a hip replacement operation. The process is executed both to determine size of the implants and to plan their positions. The plans can be accessible in the operating theatre and are referred to and / or sometimes modified during the operation. Programs for pre-operative planning include TraumaCAD Digital Orthopedic Templating (Brainlab AG Munich) and Orthoplan 2.0 (Radlink Inc). Figure 14A shows a flow diagram of the pre-operative planning process 1400 for setting a device for aligning a guide wire with a bone.

[0095] To illustrate the pre-operative planning process 1400, an example of setting the head guide 1 for aligning the guide wire 59 with the femur bone 57 will be discussed.

[0096] Step 1402 of the pre-operative planning process 1400 comprises accessing image data of an image of said bone. The image data may be any suitable image data, for example 2D or 3D image data. The image data may be present in data files accessible by a computing device. The image data may also be captured and immediately uploaded to the computing device for access. The image data may be captured by any suitable image capturing device, such as an X-ray detector, and uploaded to a suitable image processing means, such as TraumaCAD. It is preferable that an X-ray image is used, because parameters may be more easily identifiable, as discussed further below.

[0097] In the present example, image data of the femur bone 57 is accessed. Figure 8 shows a 2D X-ray image of the femur bone 57. The X-ray image may be captured at any time preceding the pre-operative planning process 1400, but it may be advantageous to use image data that is most recently captured.

[0098] Step 1404 of the pre-operative planning process 1400 comprises identifying one or more positioning parameters based on the image data obtained from the image of said bone.

[0099] In the context of the present example, the head guide 1 aligning the guide wire 59 with the femur bone 57, the one or more positioning parameters include: an inferior jaw spacing; a superior jaw position; and a guide member angle. The inferior jaw spacing corresponds to a spacing between the fixed jaw 43 and the moving jaw 44, for example as indicated by the second separation gauge (i.e., the measurement scale 50). The superior jaw position corresponds to a position of the superior jaw 34 with respect to a longitudinal axis of the head guide 1 , for example as indicated by the displacement gauge (i.e., the letter scale 14). The guide member angle corresponds to an angle of the guide member with respect to the longitudinal axis of the device, for example as indicated by the angular gauge (i.e., the protractor 15).

[0100] Identifying the one or more positioning parameters comprises the sub-steps, as shown in Figure 14B: generating 1404A a digital template; superimposing 1404B the digital template over the image of said bone; determining 1404C a suitable position for the digital template; identifying 1404D one or more positioning points; and identifying 1404E the one or more positioning parameters based on the one or more positioning points.

[0101] Generating 1404A the digital template may comprise receiving a user input; and generating the digital template based on the user input. The user input may comprise a selection of a digital template from a pre-defined set of digital templates.

[0102] In the present example, the digital template is a digital template of a resurfacing head implant for a femur bone. Figure 8 shows a digital template of a resurfacing head implant 59 superimposed 1404B onto the X-ray image of the femur bone. The head implant 59 is shown in outline cross-section.

[0103] The digital template may further comprise an assistance overlay. Figure 8 shows an example assistance overlay comprising: a first line 60 extending from the central axis of the head implant 59; a second line 61 defining a femur shaft axis; and an angle 62 between the first line 60 and the second line 61. The angle 62 between these two lines is shown to be 143 degrees. The angle 62 is the varus-valgus angle, sometimes referred to as the stem-shaft axis. The angle 62 is an important angle for determining the suitable position of the digital template (i.e. , the resurfacing head implant 59).

[0104] Determining 1404C the suitable position for the digital template may comprise receiving a user input; and repositioning the digital template based on the user input. The user input may comprise a click and drag operation by a cursor. Determining the suitable position for the digital template may be easier with the assistance overlay on the image of said bone.

[0105] In the present example, with use of the assistance overlay, the resurfacing head implant axis 60 should be positioned as close to vertical as possible, so the varus-valgus angle 62 is at least greater than 130 degrees and preferably within the range 135 - 145 degrees. Thus, the first line 60 and the second line 61 assist in determining the suitable position of the digital template. Additional assistance overlay features may be used, for example additional lines.

[0106] Identifying 1404D the one or more positioning points may be achieved by receiving a user input; and generating the one or more positioning points based on the user input. Alternatively, the one or more positioning points may be identified using a suitable algorithm.

[0107] In the present example of the head guide 1 for aligning the guide wire 59 with a femur bone 57, a first positioning point, a second positioning point, and a third positioning point are identified. Figure 9 shows a digital X-ray image including the first, second, and third positioning points. The positioning points were added following a user input, for example following a click operation at the respective positions of the image. The first point 63 corresponds to the fixed jaw 43 of the inferior jaw sub-assembly 33; a second point 64 corresponds to the moving jaw 44 of the inferior jaw sub-assembly 33; and a third point 65 corresponds to the jaw 34 of the superior jaw sub-assembly 32. The first point 63 is positioned in the nook at the head-neck junction of the femur bone. The second point 64 is spaced as far apart as possible from first point 63, as close as possible to the lesser trochanter 66 and within the confines of capsule (soft tissue) attachments to the lesser trochanter 66. The third point is positioned in a nook at the shortest distance across the neck from the first point 63. All three positions are easy to locate on an X-ray planner.

[0108] Identifying 1404E the one or more positioning parameters based on the one or more positioning points may be achieved automatically, for example using an algorithm that extrapolates the positioning parameters based on the positioning points.

[0109] Identifying 1404E the one or more positioning parameters based on the one or more positioning points may alternatively be achieved manually by: generating a second digital template; aligning the second digital template with the one or more positioning points; and identifying the one or more positioning parameters based on the position of the one or more positioning points with respect to the second digital template.

[0110] In the context of the head guide 1 aligning the guide wire 59 with the femur bone 57, the second digital template is a digital template comprising a first scale and a second scale. Figure 10 shows a second digital template 67 comprising a first scale 68; a second scale 69; a first line 70 extending perpendicular from a first edge of the first scale 68; and a second line 71 extending perpendicular from a second edge of the second scale 69. The first scale 68 corresponds to a separation between the inferior jaws 43, 44. The first scale 68 is a millimetre scale 68. The second scale 69 corresponds to a position of the superior jaw 34. The second scale 69 is a letter scale 69. The second scale 69 is centred on the first line 70. Aligning the second digital template 67 with the one or more positioning points comprises aligning the first scale 68 with the first point 63 and the second point 64. This template can be moved and angled independently of the head implant template which remains in the fixed (planned) position. Figure 11 shows the second digital template 67 superimposed onto the X-ray image, with the first scale 68 aligned with the first point 63 and the second point 64. The first scale 68 is positioned such that the zero position overlays the first point 63. Due to this alignment, the second scale 69 overlays the third point 65.

[0111] Thus, the one or more positioning parameters can be identified 1404E based on the position of the second digital template. In particular, the inferior jaw spacing (i.e., the distance between the first point 63 and the second point 64) can be determined from the first scale 68. As shown in Figure 11 , the distance between the first point 63 and the second point 64 is 31 mm. Thus, the inferior jaw spacing is 31 mm. The superior jaw position is the position of the third point 65 with respect to the second scale 69. Thus, the superior jaw position is ‘C’. The swing arm angle is determined as an angle 73 between the second line 71 and the head implant axis 60. Thus, the swing arm angle is 88 degrees.

[0112] Figure 13 shows how, even without the second digital template, manual measurements can be taken within the planning programs from which the head guide settings can be derived. However, some interpretation of the superior measurement is required via a look-up table, in this case, to determine that 5.1 mm (74) is closest to position ‘C’ on the letter scale. Thus, the use of the second digital template may be advantageous with respect to the accuracy of the head guide settings.

[0113] Step 1406 of the pre-operative planning process 1400 comprises adjusting the device based on the one or more positioning parameters.

[0114] In the context of the head guide 1 aligning the guide wire 59 with the femur bone 57, the inferior jaw spacing; the superior jaw position; and the swing arm angle are used to set the head guide 1. In particular, the inferior jaw spacing can be adjusted until the measurement scale 50 reads 31 mm, the superior jaw position can be adjusted until it reads ‘C’, and the guide member angle can be adjusted until the guide member aligns with 88 degrees on the protractor 15. Thus, the jaw gripping positions will correspond closely to the positions of the three- points identified on the X-ray planner when the head guide 1 is clamped on the femoral neck. When the guide wire 59 is drilled into the femur 57, it should correspond closely to the axis 60 of the resurfacing head template as planned. The purpose of the head guide 1 is to position the head axis central within the femoral neck and at the appropriate varus-valgus angle, exactly as per the X-ray planning.

[0115] Some embodiments may assign computer processing tasks to recipient processors, for example, but not limited to CPUs, GPUs, DSPs, GP-GPUs, quantum processor and / or processors optimised for artificial intelligence tasks. In such embodiments, the processors are the recipients and the processing tasks are the opportunities. In such embodiments, in for example, a complex cloud computing infrastructure, a large number of tasks, of differing types, requiring execution may be received and a large number of processors may be housed within the cloud computing infrastructure.

[0116] The description provided herein may be directed to specific implementations. It should be understood that the discussion provided herein is provided for the purpose of enabling a person with ordinary skill in the art to make and use any subject matter defined herein by the subject matter of the claims.

[0117] It should be intended that the subject matter of the claims not be limited to the implementations and illustrations provided herein, but include modified forms of those implementations including portions of implementations and combinations of elements of different implementations in accordance with the claims. It should be appreciated that in the development of any such implementation, as in any engineering or design project, numerous implementation-specific decisions should be made to achieve a developers’ specific goals, such as compliance with system-related and business related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort may be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having benefit of this disclosure.

[0118] Reference has been made in detail to various implementations, examples of which are illustrated in the accompanying drawings and figures. In the detailed description, numerous specific details are set forth to provide a thorough understanding of the disclosure provided herein. However, the disclosure provided herein may be practiced without these specific details. In some other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure details of the embodiments.

[0119] It should also be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element. The first element and the second element are both elements, respectively, but they are not to be considered the same element.

[0120] The terminology used in the description of the disclosure provided herein is for the purpose of describing particular implementations and is not intended to limit the disclosure provided herein. As used in the description of the disclosure provided herein and appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term “and / or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The terms “includes,” “including,” “comprises,” and / or “comprising,” when used in this specification, specify a presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0121] As used herein, the term “if” may be construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” may be construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context. The terms “up” and “down”; “upper” and “lower”; “upwardly” and “downwardly”; “below” and “above”; and other similar terms indicating relative positions above or below a given point or element may be used in connection with some implementations of various technologies described herein.

[0122] While the foregoing is directed to implementations of various techniques described herein, other and further implementations may be devised in accordance with the disclosure herein, which may be determined by the claims that follow. Although the subject matter has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

CLAIMS1 . A device for aligning a guide wire with a bone, said device comprising: at least one superior jaw configurable to contact a portion of the bone; at least two inferior jaws configurable to contact different portions of the bone; a guide member configurable to align a guide wire to the bone; wherein the positions of at least one of the at least two inferior jaws and the guide member, and optionally the at least one superior jaw, are independently adjustable.

2. The device of claim 1 , wherein: the at least one of the inferior jaws, and optionally the at least one superior jaw, are moveable with respect to a longitudinal axis of the device; the at least one superior jaw is moveable away from or towards the at least two inferior jaws; and the guide member is angularly adjustable.

3. The device of claim 1 or claim 2, further comprising a centring element for maintaining a central position of the guide member between the at least one superior jaw and the at least two inferior jaws.

4. The device of claim 2 or claim 3, further comprising a frame, wherein the frame comprises: a central body for supporting the guide member; a first side for supporting the at least one superior jaw; and a second side for supporting the at least two inferior jaws; wherein the first side and the second side are arranged to move in parallel with respect to one another, such that superior jaw can be displaced with respect to the at least two inferior jaws.

5. The device of claim 4, wherein the guide member is pivotally connected to the central body.

6. The device of claim 5, wherein a pivoting centre of the guide member is projected to a virtual position, the virtual position located on a central axis of the central body.

7. The device of any of claims 4 to 6, wherein the parallel motion is provided by a displacement means arranged to move the first side and the second side with respect to one another.

8. The device of claim 7, wherein the displacement means comprises a scissor clamp mechanism connecting the central body with the first side and the second side.

9. The device of claim 7, wherein the displacement means comprises a gear the displacement means comprises a gear arrangement having a circular gear engaging first and second linear gears, wherein the circular gear is connected to the central body, the first linear gear is connected to the first side, and the second linear gear is connected to the second side10. The device of any of claims 4 to 9, wherein the at least one superior jaw is slidably connected to the frame, such that the superior jaw can move along the longitudinal axis of the frame.11 . The device of any of claims 4 to 10, wherein the at least one superior jaw connects to the frame via a first connection means, the at least two inferior jaws connect to the frame via a second connections means, and the first connection means is incompatible with the second connection means.

12. The device of any preceding claim, wherein the at least two inferior jaws comprise: a fixed jaw; and a moving jaw; wherein the moving jaw is slidably connected to the fixed jaw, such that the moving jaw can move relative to the fixed jaw.

13. The device of any preceding claim, further comprising a displacement gauge for determining a superior jaw position; and / or a separation gauge for measuring a separation of the at least two inferior jaws.

14. The device of any preceding claim, further comprising an angular gauge for gauging an angle of the guide member with respect to a longitudinal axis of the device.

15. The device of any preceding claim, further comprising a locking means to prevent the jaws from moving away from the longitudinal axis of the device.

16. The device of any preceding claim, wherein the at least one superior jaw and the at least two inferior jaws are shaped to at least partially conform to the shape of the bone.

17. A pre-operative planning process for setting a device for aligning a guide wire with a bone, the process comprising the steps of: accessing image data of an image of said bone; identifying one or more positioning parameters based on the image data; and adjusting the device based on the one or more positioning parameters.

18. The pre-operative planning process of claim 17, wherein identifying the one or more positioning parameters comprises: generating a digital template; superimposing the digital template over the image of said bone; determining a suitable position for the digital template; identifying one or more positioning points; and identifying the one or more positioning parameters based on the one or more positioning points.

19. The pre-operative planning process of claim 18, wherein the digital template comprises an assistance overlay.

20. The pre-operative planning process of claim 18 or claim 19, wherein identifying the one or more positioning parameters based on the one or more positioning points comprises: generating a second digital template; aligning the second digital template with the one or more positioning points; and identifying the one or more positioning parameters based on the position of the one or more positioning points with respect to the second digital template.

21. The pre-operative planning process of any of claims 17 to 20, wherein the device is the device of any of Claims 1 to 16.

22. The pre-operative planning process of claim 21 , wherein the one or more positioning parameters comprise: an inferior jaw spacing; a superior jaw position; and a guide member angle.

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