A prosthesis kit

Abstract

A prosthesis kit 100 for fixing a prosthesis to a bone, comprising: a mounting plate 200 for coupling to the bone; a prosthesis 102 for coupling to the mounting plate, comprising a body 104, shaped to

Description

TECHNICAL FIELD

[0001] The present invention relates to a prosthesis kit for fixing a prosthesis, such as a femoral implant, to a bone. BACKGROUND

[0002] Prosthetic implants can be used to partially or completely replace diseased and / or damaged joint tissue. Such implants may include articulating surfaces that replace the bone’s natural articulating surfaces. For example, an implant for a knee replacement may include a femoral implant and / or a tibial implant. A femoral implant may be implanted on the distal end of the femur and may replace the articulating surfaces of the femur. A tibial implant may be implanted on the proximal end of the tibia and may replace the articulating surfaces of the tibia. In operation, the articulating surfaces of the femoral implant articulate against the articulating surfaces of the tibial implant.

[0003] Various materials have been used for the femoral and tibial implants. For example, the implants may be made from metal, for instance, cobalt-chrome. Solid metal implants may have a significantly higher stiffness and tensile strength than bone. As a result, such metal implants can have an increased tendency to shield the underlying bone from stresses that would normally be applied to the joint during use. According to Wolff’s law, bone remodels in response to applied loads. If a bone is shielded from these loads, the bone will not be exposed to the stimulus required to maintain bone mass. This can lead to a loss of bone mass that may e.g. increase the chances of the implant coming loose. Knee implants formed from polymeric compositions may be formulated to have mechanical properties that are more compatible with the mechanical properties of bone.

[0004] To implant a femoral implant onto the distal femoral bone, the bone may need to be resected. Implants are typically initially held in position using a bone cement, e.g. polymethylmethacrylate (PMMA). Preparation and application of the bone cement in an operating theatre may add time and complexity to the surgical procedure. A bone cement fixation requires a mechanical bond to be formed between the cement and the bone, as well as a mechanical bond between the cement and the implant. In some instances, large loads transferred through the implant can cause one, or both, of these mechanical bonds to degrade, particularly over time. Furthermore, some patients may have adverse reactions to the bone cement.

[0005] Cementless implants may be used. Primary fixation of cementless implants may be obtained by the formation of compressive forces and subsequent shearing forces at the boneimplant interface during implantation. These compressive and shearing forces can be influenced by, for example, the interference fit and the frictional properties of the implant surface. The interference fit refers to the dimensional difference between the prepared bone cuts and the implant. The femoral bone may be cut slightly larger than the internal implant dimensions, resulting in a press fixation after implantation.

[0006] This disclosure aims to ameliorate the aforementioned disadvantages by providing an improved prosthesis kit and method for implantation. BRIEF SUMMARY

[0007] According to the present disclosure there is provided a prosthesis kit for fixing a prosthesis to a bone, comprising: a mounting plate for coupling to the bone; a prosthesis for coupling to the mounting plate, comprising a body, shaped to at least partially cover the mounting plate, and clips disposed on opposite sides of the body for engaging with mating surfaces of the mounting plate; wherein the prosthesis is configured to couple to the mounting plate by way of a snap fit connection between the clips and the mating surfaces of the mounting plate.

[0008] The prosthesis kit may be suitable for use in total or partial knee replacement surgeries.

[0009] The mounting plate may comprise an interior surface for engaging with an outer surface of the bone.

[0010] The mounting plate may be configured to at least partially surround a terminal end of the bone.

[0011] The bone may comprise a resected surface. The interior surface of the mounting plate may be configured to engage the resected surface.

[0012] The prosthesis may comprise or essentially consist of a prosthetic joint comprising an articulating surface shaped to interface with an opposing surface of a neighboring joint. The prosthesis may comprise or essentially consist of a femoral implant.

[0013] The prosthesis may be configured as any prosthetic implant suitable for a human or animal. For example, the prosthesis may comprise a prosthetic joint such as a tibial implant for fixing to a tibia.

[0014] The mounting plate may comprise an exterior facing surface and an interior surface configured to engage an outer surface of the bone.

[0015] An inner surface of the prosthesis may be shaped conformally to the exterior facing surface of mounting plate.

[0016] The prosthesis may be shaped to completely cover the mounting plate so that in use, the mounting plate is completely encapsulated between the bone and the prosthesis.

[0017] The mounting plate may comprise two arms: a first arm for engaging with a medial condyle of the bone; and a second arm for engaging with a lateral condyle of the bone.

[0018] The first arm may be connected to the second arm at a front of the mounting plate such that the mounting plate is V-shaped in top-view. The front of the mounting plate may be configured to attach to an anterior side of the bone e.g., at or proximal to the patellofemoral groove of the human femur. The rear of the mounting plate may be configured to attach to a posterior side of the bone e.g., a posterior side of the human femur.

[0019] The mounting plate may have an angular profile.

[0020] The mounting plate may comprise three panels which define termini of the mounting plate. The three panels may include: a first panel which defines the anterior hub for connecting to an anterior of the bone; and two second panels configured to connect to a posterior of the bone (e.g., at the medial condyle and lateral condyle respectively). The second panels may be coplanar with one another. The first panel may be arranged parallel to the second panels. This configuration may allow the mounting plate to be easily inserted onto the bone during installation (e.g., by hammering the mounting plate downwards along a major axis of the bone).

[0021] The first panel may be connected to each of the second panels by one or more intermediate panels. For example, the first panel may be connected to each of the second panels by a chain of consecutive intermediate panels (e.g., three consecutive intermediate panels). Each intermediate panel may define a 45° angle with each neighbouring panel such that the mounting plate profile is C-shaped in plan-view. As the resected surface may be cut to match the shape of the interior surface of the mounting plate, configuring the mounting plate in this way may minimise the complexity associated with resecting the bone as flat 45° angle cuts may be easier to re-produce accurately.

[0022] At least one intermediate panel may be arranged perpendicular to the first panel and the second panels. Such an intermediate panel may define a contact surface for hammering the mounting plate onto the bone. Providing a flat contact surface perpendicular to the direction of force transfer from the hammer may ease installation of the mounting plate and prevent damage to the mounting plate during installation.

[0023] The prosthesis may be configured such that when the body is linearly translated towards the mounting plate, the clips resiliently deflect outwards over the exterior facing surface of the mounting plate until the clips latch onto the mating surfaces of the mounting plate to couple the prosthesis to the mounting plate.

[0024] The mounting plate may be bound by a side surface which surrounds the mounting plate. The side surface may comprise the mating surfaces such that when the prosthesis is coupled to the mounting plate, the clips engage the side surface of the mounting plate.

[0025] The mounting plate may comprise one or more recesses for accommodating the clips. The or each recess may define one of the mating surfaces. The or each recess may extend through the full thickness of the mounting plate.

[0026] The mounting plate may have a greater stiffness than the prosthesis such that the prosthesis deflects as it is coupled to the mounting plate.

[0027] The mounting plate may comprise or essentially consist of a metal such as titanium, titanium alloy or steel. The interior surface of the mounting plate may comprise porous titanium to promote bone growth into the mounting plate.

[0028] The prosthesis may comprise one or more pins for insertion into one or more corresponding recesses in the bone.

[0029] The mounting plate may comprise one or more apertures. Each of the one or more apertures may be configured to receive a respective one of the one or more pins when the prosthesis is coupled to the mounting plate.

[0030] The mounting plate may comprise a plurality of apertures. Each of the plurality of apertures may perforate the full thickness of the mounting plate. The plurality of apertures may comprise a first set of apertures and a second set of apertures. The first set of apertures may comprise one or more apertures. The second set of apertures may comprise one or more apertures.

[0031] The prosthesis kit may comprise one or more fasteners, such as bone screws, for fixing the mounting plate to the bone. Each of the first set of apertures may be configured to receive a respective fastener of the one or more fasteners. Some of the first set of apertures may be located at the rear of the mounting plate while others of the first set of apertures may be located at the front of the mounting plate.

[0032] Some or all of the first set of apertures may comprise a recessed portion configured to receive a head of one of the one or more fasteners. For example, some or all of the first set of apertures may comprise a countersink or counterbore suitable for receiving the head of one of the one or more fasteners.

[0033] Each of the second set of apertures may be configured to receive a respective pin of the prosthesis. The pins may be suitable for aligning the prosthesis with respect to the mounting plate and the bone prior to securing the prosthesis to the mounting plate.

[0034] As the prosthesis may be coupled to the mounting plate and not directly to the bone, ribs / protrusions used to secure the prosthesis to the resected surface of the bone may not be required.

[0035] The inner surface of prosthesis may be substantially smooth. Beneficially, this may reduce manufacturing cost for the prosthesis kit and / or improve force transfer from the articulating surface of the prosthesis to the bone.

[0036] The prosthesis may comprise a femoral implant.

[0037] Each of the clips may be disposed on a peripheral edge of the prosthesis.

[0038] At least one of the clips may comprise a rib shaped protrusion. The rib shaped protrusion(s) may be curved.

[0039] The body may comprise a first condyle and a second condyle which branch from an anterior hub to form a curved V-shape.

[0040] The clips may comprise a first clip located at the first condyle, a second clip located at the second condyle and a third clip located at the anterior hub. The first condyle may be shaped as a medial condyle of a human femur. The second condyle may be shaped as a lateral condyle of a human femur. The first condyle and the second condyle may have a gap therebetween defining an intercondylar notch.

[0041] The first clip may comprise a curved rib which follows a profile of the first condyle. The second clip may comprise a curved rib which follows a profile of the second condyle.

[0042] The prosthesis may comprise or essentially consist of a polymer . For example, the prosthesis may comprise or essentially consist of polyaryletherketones (PAEK), such as polyetheretherketone (PEEK) or polyetherketoneketone (PEKK), polyphenylene sulphide (PPS), polyetherimide (PEI), polycarbonate (PC), polyethylene terephthalate (PET), polyamide (PA), poly(methyl methacrylate) or a combination thereof.

[0043] The prosthesis may consist of a single piece of integrally molded polymer, i.e., moulded as a single component.

[0044] The clips may comprise a polymer material. The polymer material may be polyaryletherketones (PAEK), such as polyetheretherketone (PEEK) or polyetherketoneketone (PEKK), polyphenylene sulphide (PPS), polyetherimide (PEI), polycarbonate (PC), polyethylene terephthalate (PET), polyamide (PA), poly(methyl methacrylate) or a combination thereof.

[0045] Each of the clips may comprise a leading surface and a trailing surface. The trailing surface may be shaped to inhibit decoupling of the prosthesis from the mounting plate. The leading surface may be sloped to facilitate coupling of the prosthesis to the mounting plate.

[0046] The mounting plate may comprise and exterior surface and an interior surface. The interior surface may be configured to engage an outer surface of the bone.

[0047] The mating surfaces may be perpendicular to each of the exterior surface and the interior surface. The mating surfaces may make an acute angle with the interior surface. The mating surfaces may make an obtuse angle with the exterior surface.

[0048] Trailing surfaces of the clips may be configured to be coplanar with and abut a respective mating surface of the mounting plate when the prosthesis kit is assembled.

[0049] The prosthesis may comprise a rim configured to abut the side surface of the mounting plate. The rim may bound the inner surface along its periphery. The rim may project substantially perpendicularly away from the inner surface.

[0050] The rim may be configured to align the prosthesis with respect to the mounting plate prior to securing the prosthesis to the mounting plate. The rim may be configured surround and cover the side surface of the mounting plate when the prosthesis kit is assembled.

[0051] The rim may partially overlap the side surface of the mounting plate. For example, the rim may discontinuously bound the inner surface. The rim may be configured to prevent the prosthesis from being slid off the mounting plate in a transverse direction (perpendicular to the major axis of the bone).

[0052] The prosthesis of the prosthesis kit may be according to any one or combination of the of the following statements.

[0053] According to the present disclosure there is also provided a prosthesis for coupling to a mounting plate attached to a bone such that the prosthesis is fixed to the bone, the prosthesis comprising: a body shaped to at least partially cover the mounting plate; and clips disposed on opposite sides of the body for engaging with mating surfaces of the mounting plate. The prosthesis may comprise a prosthetic joint comprising an articulating surface shaped to interface with an opposing surface of a neighboring joint.

[0054] The prosthesis may comprise a femoral implant.

[0055] Each of the clips may be disposed on a peripheral edge of the prosthesis.

[0056] At least one of the clips may comprise a rib shaped protrusion. The rib shaped protrusion(s) may be curved.

[0057] The body may comprise a first condyle and a second condyle which branch from an anterior hub to form a curved V-shape.

[0058] The clips may comprise a first clip located at the first condyle, a second clip located at the second condyle and a third clip located at the anterior hub. The first condyle may be shaped as a medial condyle of a human femur. The second condyle may be shaped as a lateral condyle of a human femur. The first condyle and the second condyle may have a gap therebetween defining an intercondylar notch. The clips may comprise a first clip located at the first condyle, a second clip located at the second condyle and a third clip located at the anterior hub. The first clip may comprise a curved rib which follows a profile of the first condyle. The second clip may comprise a curved rib which follows a profile of the second condyle.

[0059] The prosthesis may comprise or essentially consist of a polymer material. For example, the prosthesis may comprise or essentially consist of polyaryletherketones (PAEK), such as polyetheretherketone (PEEK) or polyetherketoneketone (PEKK), polyphenylene sulphide (PPS), polyetherimide (PEI), polycarbonate (PC), polyethylene terephthalate (PET), polyamide (PA), poly(methyl methacrylate) or a combination thereof.

[0060] The prosthesis may consist of a single piece of integrally molded plastic.

[0061] The clips may comprise a polymer material. The polymer material may be polyaryletherketones (PAEK), such as polyetheretherketone (PEEK) or polyetherketoneketone (PEKK), polyphenylene sulphide (PPS), polyetherimide (PEI), polycarbonate (PC), polyethylene terephthalate (PET), polyamide (PA), poly(methyl methacrylate) or a combination thereof.

[0062] Each of the clips may comprise a leading surface and a trailing surface. The trailing surface may be shaped to inhibit decoupling of the prosthesis from the mounting plate. . The leading surface may be sloped to facilitate coupling of the prosthesis to the mounting plate.

[0063] The mating surfaces may be perpendicular to each of the exterior facing surface and the interior surface. The mating surfaces may make an acute angle with the interior surface. The mating surfaces may make an obtuse angle with the exterior facing surface.

[0064] Trailing surfaces of the clips may be configured to be coplanar with and abut a respective mating surface of the mounting plate when the prosthesis kit is assembled.

[0065] The prosthesis may be configured such that when the body is linearly translated m a first direction towards the mounting plate, the clips resiliently deflect outwards over the exterior facing surface of the mounting plate until the clips latch onto the mating surfaces of the mounting plate to couple the prosthesis to the mounting plate.

[0066] The prosthesis may comprise one or more pins for insertion into one or more corresponding recesses in the bone.

[0067] The prosthesis may comprise an inner surface. The inner surface of prosthesis may be substantially smooth. Beneficially, this may reduce manufacturing cost for the prosthesis kit and / or improve force transfer from the articulating surface of the prosthesis to the bone.

[0068] The prosthesis may be suitable for use in total or partial knee replacement surgeries.

[0069] The mounting plate may comprise an interior surface for engaging with an outer surface of the bone. The mounting plate may be configured to at least partially surround a terminal end of the bone. The bone may comprise a resected surface. The resected surface may be configured to engage the interior surface of the mounting plate.

[0070] The prosthesis may comprise or essentially consist of a prosthetic joint comprising an articulating surface shaped to interface with an opposing surface of a neighboring joint. The prosthesis may comprise or essentially consist of a femoral implant.

[0071] The prosthesis may be configured as any prosthetic implant suitable for a human or animal. For example, the prosthesis may comprise a prosthetic joint such as a tibial implant for fixing to a tibia.

[0072] An inner surface of the prosthesis may be shaped conformally to the exterior surface of mounting plate.

[0073] The prosthesis may be shaped to completely cover the mounting plate so that in use, the mounting plate is completely encapsulated between the bone and the prosthesis.

[0074] The prosthesis may be configured such that when the body is linearly translated towards the mounting plate, the clips resiliently deflect outwards over the exterior surface of the mounting plate until the clips latch onto the mating surfaces of the mounting plate to couple the prosthesis to the mounting plate.

[0075] The mounting plate may be bound by a side surface which surrounds the mounting plate. The side surface may comprise the mating surfaces such that when the prosthesis is coupled to the mounting plate, the clips engage the side surface of the mounting plate.

[0076] The mounting plate may comprise one or more recesses for accommodating the clips. The or each recess may define one of the mating surfaces. The or each recess may extend through the full thickness of the mounting plate. The mounting plate may be stiffer than the prosthesis such that the mounting plate is not configured to deform when the prosthesis is coupled to the mounting plate. The mounting plate may comprise or essentially consist of a metal such as titanium, titanium alloy or steel. The interior surface of the mounting plate may comprise porous titanium to promote bone growth into the mounting plate.

[0077] The prosthesis may comprise one or more pins for insertion into one or more corresponding recesses in the bone. The one or more pins may be suitable for aligning the prosthesis with respect to the mounting plate and the bone prior to securing the prosthesis to the mounting plate.

[0078] The prosthesis may comprise a rim configured to abut the side surface of the mounting plate. The rim may bound the inner surface along its periphery. The rim may project substantially perpendicularly away from the inner surface.

[0079] The rim may be configured to align the prosthesis with respect to the mounting plate prior to securing the prosthesis to the mounting plate. The rim may be configured surround and cover the side surface of the mounting plate when the prosthesis is coupled to the mounting plate.

[0080] The rim may be configured to partially overlap the side surface of the mounting plate. For example, the rim may discontinuously bound the inner surface. The rim may be configured to prevent the prosthesis from being slid off the mounting plate in a transverse direction (perpendicular to the major axis of the bone).

[0081] According to the present disclosure there is also provided a mounting plate for attaching a prosthesis to a bone, the mounting plate being attachable to the bone and comprising mating surfaces for coupling with clips of the prosthesis to form a snap fit connection.

[0082] The mounting plate may comprise an interior surface for engaging with an outer surface of the bone.

[0083] The mounting plate may be configured to at least partially surround a terminal end of the bone.

[0084] The bone may comprise a resected surface. The interior surface of the mounting plate may be configured to engage the resected surface.

[0085] The mounting plate may comprise an exterior facing surface and an interior surface configured to engage an outer surface of the bone.

[0086] The exterior facing surface of mounting plate may be shaped conformally to an inner surface of the prosthesis.

[0087] The mounting plate may comprise two arms: a first arm for engaging with a medial condyle of the bone; and a second arm for engaging with a lateral condyle of the bone. The first arm may be connected to the second arm at a front of the mounting plate such that the mounting plate is V-shaped in top-view. The front of the mounting plate may be configured to attach to an anterior side of the bone eg. at or proximal to the patellofemoral groove of the human femur. The rear of the mounting plate may be configured to attach to a posterior side of the bone e.g., a posterior side of the human femur.

[0088] The mounting plate may have an angular profile.

[0089] The mounting plate may comprise three panels which define termini of the mounting plate. The three panels may include: a first panel which defines the anterior hub for connecting to an anterior of the bone; and two second panels configured to connect to a posterior of the bone (e.g., at the medial condyle and lateral condyle respectively). The second panels may be coplanar with one another. The first panel may be arranged parallel to the second panels. This configuration may allow the mounting plate to be easily inserted onto the bone during installation (e.g., by hammering the mounting plate downwards along a major axis of the bone).

[0090] The first panel may be connected to each of the second panels by one or more intermediate panels. For example, the first panel may be connected to each of the second panels by a chain of consecutive intermediate panels (e.g., three consecutive intermediate panels). Each intermediate panel may define a 45° angle with each neighbouring panel such that the mounting plate profile is C-shaped in plan-view. As the resected surface may be cut to match the shape of the interior surface of the mounting plate, configuring the mounting plate in this way may minimise the complexity associated with resecting the bone as flat 45° angle cuts may be easier to re-produce accurately.

[0091] At least one intermediate panel may be arranged perpendicular to the first panel and the second panels. Such an intermediate panel may define a contact surface for hammering the mounting plate onto the bone. Providing a flat contact surface perpendicular to the direction of force transfer from the hammer may ease installation of the mounting plate and prevent damage to the mounting plate during installation.

[0092] The mounting plate may be bound by a side surface which surrounds the mounting plate. The side surface may comprise the mating surfaces such that when the prosthesis is coupled to the mounting plate, the clips engage the side surface of the mounting plate.

[0093] The mounting plate may comprise one or more recesses for accommodating the clips. The or each recess may define one of the mating surfaces. The or each recess may extend through the full thickness of the mounting plate.

[0094] The mounting plate may have a greater stiffness than the prosthesis such that the prosthesis deflects as it is coupled to the mounting plate.

[0095] The mounting plate may comprise or essentially consist of a metal such as titanium, titanium alloy or steel. The interior surface of the mounting plate may comprise porous titanium to promote bone growth into the mounting plate.

[0096] The prosthesis may comprise one or more pins for insertion into one or more corresponding recesses in the bone.

[0097] The mounting plate may comprise one or more apertures. Each of the one or more apertures may be configured to receive a respective one of the one or more pins when the prosthesis is coupled to the mounting plate.

[0098] The mounting plate may comprise a plurality of apertures. Each of the plurality of apertures may perforate the full thickness of the mounting plate. The plurality of apertures may comprise a first set of apertures and a second set of apertures. The first set of apertures may comprise one or more apertures. The second set of apertures may comprise one or more apertures.

[0099] Each of the first set of apertures may be configured to receive a respective fastener (such as a bone screw). Some of the first set of apertures may be located at the rear of the mounting plate while others of the first set of apertures may be located at the front of the mounting plate.

[0100] Some or all of the first set of apertures may comprise a recessed portion configured to receive a head of a fastener. For example, some or all of the first set of apertures may comprise a countersink or counterbore suitable for receiving the head of a fastener.

[0101] Each of the second set of apertures may be configured to receive a respective pin of the prosthesis. The pins may be suitable for aligning the prosthesis with respect to the mounting plate and the bone prior to securing the prosthesis to the mounting plate.

[0102] According to the present disclosure there is provided a method of fixing a prosthesis to a bone comprising the steps of: attaching a mounting plate to the bone; coupling the prosthesis to the mounting plate, the prosthesis comprising a body shaped to at least partially cover the mounting plate and clips disposed on opposite sides of the body for engaging with mating surfaces of the mounting plate to form a snap fit connection between the clips and the mating surfaces of the mounting plate.

[0103] Coupling the prosthesis to the mounting plate may involve translating the body linearly towards the mounting plate thereby resiliently deflecting the clips outwards over an exterior facing surface of the mounting plate until the clips latch onto the mating surfaces of the mounting plate to couple the prosthesis to the mounting plate.

[0104] The method may comprise the step of resecting a portion of the bone to form a resected surface configured to receive the mounting plate.

[0105] Attaching the mounting plate to the bone may involve fixedly coupling the mounting plate to the bone such that the interior surface abuts the resected surface of the bone.

[0106] The step of attaching the mounting plate to the bone may be completed before the step of coupling the prosthesis to the mounting plate.

[0107] The method may further include drilling one or more holes in the bone for receiving a respective one of the one or more pins.

[0108] Drilling one or more holes in the bone may be completed before or after the bone is resected to form the resected surface. The one or more holes may be drilled in the bone after the mounting plate has been attached to the bone.

[0109] Features discussed in relation to each aspect of the invention are to be understood to be applicable to any other aspect of the invention unless the context clearly indicates otherwise. [OHO] Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims. Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

[0111] FIG. 1 illustrates a prosthesis kit. [0H2] FIG. 2 illustrates the mounting plate of the prosthesis kit before the mounting plate is attached to a bone.

[0113] FIG. 3 illustrates the mounting plate of FIG. 2 being fixed to the bone.

[0114] FIG. 4A shows a front view of the mounting plate of FIG. 2 fixed to the bone.

[0115] FIG. 4B illustrates a rear view of the mounting plate of FIG. 2 fixed to the bone. [0H6] FIG. 5 illustrates the prosthesis kit of FIG. 1 during assembly.

[0117] FIG. 6A shows a front view of a prosthesis.

[0118] FIG. 6B shows a side view of the prosthesis of FIG. 6A.

[0119] FIG. 6C shows a rear view of the prosthesis of FIG. 6A.

[0120] FIG. 7 shows a cross-sectional view of the prosthesis kit of FIG. 1.

[0121] FIG. 8 illustrates a method of fixing a prosthesis to a bone. DETAILED DESCRIPTION

[0122] FIG. 1 shows a prosthesis kit 100 that includes a prosthesis 102 and a mounting plate 200 for coupling the prosthesis 102 to a bone 300. In this example, the mounting plate 200 is configured to at least partially surround a terminal end 302 of the bone 300.

[0123] The prosthesis 102 comprises a body 104 which is shaped to at least partially cover the mounting plate 200. In some examples, the prosthesis 102 may be shaped to completely cover the mounting plate 200 so that in use, the mounting plate 200 is completely encapsulated between the bone 300 and the prosthesis 102.

[0124] In the example shown in FIG. 1, the mounting plate 200 comprises and an interior surface 204 configured to engage an outer surface of the bone 300, and an exterior surface 202 opposite the interior surface 204.

[0125] An inner surface 106 of the prosthesis 102 is shaped conformally to the exterior surface 202 of mounting plate 200. As shown in FIG. 1, when the prosthesis kit 100 is assembled, the prosthesis 102 covers the exterior surface 202 of the mounting plate 200. A side surface 206 of the mounting plate 200 connects the exterior surface 202 to the interior surface 204. When the prosthesis kit 100 is assembled, at least part of the side surface 206 may be exposed, or the prosthesis 102 may cover the side surface 206 as described further below.

[0126] The prosthesis 102 comprises clips 108 disposed on opposite sides 112, 116 of the body 104 for engaging with mating surfaces 208 of the mounting plate 200. Specifically, the prosthesis 102 comprises at least one first clip 110 arranged at a first side 112 of the prosthesis 102 for coupling to a first mating surface 210 at a rear 212 of the mounting plate 200. The prosthesis 102 comprises at least one second clip 114 arranged at a second side 116 of the prosthesis 102 for coupling to a second mating surface 214 at a front 216 of the mounting plate 200. In this example, the mating surfaces 208 form part of the side surface 206 of the mounting plate 200.

[0127] The first clip(s) 110 and the second clip(s) 114 are arranged on opposite sides of the prosthesis 102 and arranged to engage opposite ends 212, 216 of the mounting plate 200 to couple the prosthesis 102 to the mounting plate 200. As will be described in more detail later on, the prosthesis 102 is configured to couple to the mounting plate 200 by way of a snap fit connection between the clips 108 and the mating surfaces 208 of the mounting plate 200.

[0128] In this example, the prosthesis 102 is a prosthetic joint comprising an articulating surface 118 shaped to interface with an opposing surface of a neighboring joint (not shown) such as a prosthetic tibial joint or a natural tibial joint. The prosthesis kit 100 may be suitable for use in total or partial knee replacement surgeries.

[0129] In this example, the prosthesis 102 comprises a femoral implant. The prosthesis 102 includes a first condyle 120 and a second condyle 122 which each branch from an anterior hub 124 of the prosthesis 102. As shown in FIG. 1, the anterior hub 124 forms the second side 116 of the prosthesis 102 while the first condyle 120 and the second condyle 122 project away from the anterior hub 124 towards the first side 112 of the prosthesis 102. The first condyle 120 may be shaped as a medial condyle of a human femur while the second condyle 122 may be shaped as a lateral condyle of a human femur.

[0130] The first condyle 120 and the second condyle 122 project away from the anterior hub 124 to form an arcuate V-shape. The first condyle 120 and the second condyle 122 have a gap therebetween defining an intercondylar notch. While in the present example the prosthesis 102 is configured as a femoral implant, in other examples the prosthesis 102 may be configured as any prosthetic implant suitable for a human or animal. For example, the prosthesis 102 may comprise a prosthetic joint such as a tibial implant for fixing to a tibia.

[0131] FIG. 2 to FIG. 5 show different stages of fixing the prosthesis kit 100 to the bone 300.

[0132] FIG. 2 shows the bone 300 and the mounting plate 200 of the prosthesis kit 100 before the mounting plate 200 is attached to the terminal end 302 of the bone 300.

[0133] Prior to fitting the mounting plate 200 to the bone 300, an outer surface of the terminal end 302 may be resected to form a resected surface 304. Resecting the terminal end 302 may be necessary to remove damaged bone to provide a stable foundation for fitting the mounting plate 200. In this example, the bone 300 is a femur and the resected surface 304 spans a medial condyle and a lateral condyle of the bone 300.

[0134] The interior surface 204 of the mounting plate 200 may be shaped to match the resected surface 304. In this example, the mounting plate 200 comprises two arms: a first arm 218 for engaging with the resected surface 304 at the medial condyle; and a second arm 220 for engaging with the resected surface 304 at the lateral condyle. The front 216 of the mounting plate 200 may be configured to attach to an anterior side of the bone 300. A rear 212 of the mounting plate 200 may be configured to attach to a posterior side of the bone 300. The first arm 218 is connected to the second arm 220 at the front 216 of the mounting plate 200 such that the mounting plate 200 is V-shaped in top-view. As shown in FIG. 2, the mounting plate 200 is defined by a 3D profile which is generally C-shaped in plan-view.

[0135] The mounting plate 200 comprises one or more apertures 226. In this example, the mounting plate 200 comprises a plurality of apertures including a first set of apertures 228 and a second set of apertures 230. Each of the apertures 226 may perforate the full thickness of the mounting plate 200. Each of the first set of apertures 228 and the second set of apertures 230 may comprise one or more apertures. In this example, the first set of apertures 228 comprises five apertures while the second set of apertures 230 comprises two apertures.

[0136] Each of the first set of apertures 228 is configured to receive a fastener 232, such as a bone screw, for securing the mounting plate 200 to the bone 300. The fasteners 232 are not shown in FIG. 2 but can be seen in FIG. 3 to FIG. 5.

[0137] As will be described later on with reference to FIG. 5, the prosthesis 102 may comprise one or more pins 126 which project away from the inner surface 106. Each of the second set of apertures 230 is configured to receive a respective pin 126 of the prosthesis 102. The pins 126 may serve to align the prosthesis 102 with respect to the mounting plate 200 and the bone 300 prior to securing the prosthesis 102 to the mounting plate 200.

[0138] One or more holes 306 may be drilled in the bone 300 for receiving a respective one of the pins 126. Each of the second set of apertures 230 of the mounting plate 200 may be configured to align with a respective one of the holes 306 when the mounting plate 200 is attached to the bone 300. In this example, the holes 306 have been drilled prior to fitting the mounting plate 200 to the bone 300. In other examples, some or all of the holes 306 may be drilled after the mounting plate 200 has been placed on the bone 300.

[0139] In some examples, one or more pilot holes (not shown) may be drilled in the bone 300 for receiving a respective fastener 232. The pilot holes may be positioned to align with a respective one of the first set of apertures 228. Such pilot holes may be drilled prior to fitting the mounting plate 200 to the bone 300 or after the mounting plate 200 has been placed on the bone 300 but before the mounting plate 200 has been secured to the bone 300 by way of the fasteners 232.

[0140] In this example, the mounting plate 200 is formed from a series of straight planar sections 222 connected by a series of straight parallel edges 224. The planar sections 222 are arranged such that the mounting plate 200 has an angular C-shape in plan-view. An angularly profiled mounting plate 200 such as this may prevent shearing between the mounting plate 200 and the terminal end 302 of the bone 300. Shearing forces may be propagated to the bone 300 and at each edge 224 which can relieve stresses on the fasteners 232 and prevent stress concentration at the fasteners 232.

[0141] In this example, the mounting plate 200 comprises three panels which define termini of the mounting plate 200. The three panels include: a first panel 240 which defines the anterior hub 124 for connecting to an anterior of the bone 300; and two second panels 242 configured to connect to a posterior of the bone 300 at the medial condyle and lateral condyle respectively. The second panels 242 are coplanar with one another and the first panel 240 is arranged parallel to the second panels 242. This configuration may allow the mounting plate 200 to be easily inserted onto the bone 300 during installation (e.g., by hammering the mounting plate 200 downwards along a major axis 308 of the bone 300).

[0142] The first panel 240 may be connected to each of the second panels 242 by one or more intermediate panels 244. In this example, the first panel 240 is connected to each of the second panels 242 by a chain of three consecutive intermediate panels 244. As such, the mounting plate 200 comprises six intermediate panels 244 in total: two intermediate panels 244 being connected to the first panel 240; two intermediate panels 244 being connected to the second panel 242; and two ‘central’ intermediate panels 244 connected therebetween.

[0143] Each intermediate panel 244 makes a 45° angle with each neighbouring panel such that the mounting plate 200 profile is generally C-shaped in plan-view. As the resected surface 304 must be cut to match the shape of the interior surface 204 of the mounting plate 200, configuring the mounting plate 200 in this way may minimise the complexity associated with resecting the bone 300 (as flat 45° angle cuts may be easier to re-produce accurately).

[0144] As shown in FIG. 2, the two central intermediate panels 244 are arranged perpendicular to the first panel 240 and the second panels 242. These two intermediate panels 244 may define a contact surface for hammering the mounting plate 200 onto the bone 300. Providing a flat contact surface perpendicular to the direction of force transfer from the hammer may ease installation of the mounting plate 200 and prevent damage to the mounting plate 200 during installation.

[0145] FIG. 3 shows the mounting plate 200 being fixed to the bone 300. As described earlier, the prosthesis kit 100 may comprise one or more fasteners 232 such as bone screws for fixing the mounting plate 200 to the bone 300. In this example, the prosthesis kit 100 comprises five fasteners 232, one for each of the first set of apertures 228.

[0146] Some of the first set of apertures 228 are located at the front 216 of the mounting plate 200 while others of the first set of apertures 228 are located at the rear 212 of the mounting plate 200. When the fasteners 232 are screwed into the bone 300, each end of the mounting plate 200 is compressed against the bone 300. The mounting plate 200 may be caused to deflect as the fastener 232 are tightened so that the mounting plate 200 can conform to the resected surface 304 of the bone 300. In this way, the mounting plate 200 can deform to accommodate for differences between the shape of the resected surface 304 and the interior surface 204 of the mounting plate 200. For example, the mounting plate 200 may essentially consist of a thin plate having a thickness of less than: 5 mm, 4 mm or 3 mm. In a preferred embodiment the mounting plate 200 may have a thickness of 3 mm. Providing a thin mounting plate 200 may minimise stress shielding from the mounting plate 200 allowing the bone 300 to strengthen according to Wolffs law.

[0147] Some or all of the first set of apertures 228 may comprise a recessed portion 236 configured to receive a head 234 of a fastener 232. For example, some or all of the first set of apertures 228 may comprise a countersink or counterbore for receiving a head 234 of a screw.

[0148] In the example shown in FIG. 3, each of the second set of apertures 230 consists of a through hole having a constant internal diameter along its length. In some examples, openings of each of the second set of apertures 230 may be shaped to accommodate a profile of the pin 126 of the prosthesis 102. For example, the or each pin 126 may have a stepped profile and each of the second set of apertures 230 may be stepped such that the inner surface 106 of the prosthesis 102 lies flush against the exterior surface 202 of the mounting plate 200 when the prosthesis kit 100 is assembled.

[0149] FIG. 4A and FIG. 4B show the mounting plate 200 fixed to the bone 300. As shown, when the fasteners 232 are installed, the head 234 of each fastener 232 abuts a recessed portion of a respective one of the first set of apertures 228 to secure the mounting plate 200 to the resected surface 304. Each of the recessed portions are configured to accommodate the head 234 of a respective fastener 232 such that when the fasteners 232 are installed, the fasteners 232 are flush with the exterior surface 202 of the mounting plate 200.

[0150] In an alternate example, the first set of apertures 228 may not comprise recessed portions and the heads 234 may abut the exterior surface 202 to secure the mounting plate 200 to the bone 300. In such an example, the inner surface 106 of the prosthesis 102 may have one or more recesses to accommodate the heads 234, allowing the inner surface 106 to sit flush against the exterior surface 202 of the mounting plate 200.

[0151] FIG. 5 shows the prosthesis 102 being fixed to the mounting plate 200. The inner surface 106 of the prosthesis 102 is shaped conformally to the exterior surface 202 of mounting plate 200. In this example, the mounting plate 200 has an angular inner surface 106 which is shaped to mate with the exterior surface 202 of the mounting plate 200.

[0152] As shown in FIG. 5, in this example the inner surface 106 of the prosthesis 102 comprises a plurality of struts 128. The struts 128 may increase the structural rigidity of the prosthesis 102 while minimising its weight.

[0153] In other examples, the inner surface 106 may not comprise any struts 128. For example, the inner surface 106 may be substantially smooth. In known prostheses where the prosthesis is mounted directly onto the bone, the underside of the prosthesis may have indentations for receiving bone cement for fixing the prosthesis to the bone. In this present invention, the prosthesis 102 is configured to connect to the mounting plate 200 by way of a snap fit connection. As such, it may be possible to fix the prosthesis 102 to the bone 300 without the use of bone cement or indentations in the inner surface 106 of the prosthesis 102. Beneficially, this may reduce manufacturing cost for the prosthesis kit 100 and improve force transfer from the articulating surface 118 of the prosthesis kit to the bone 300.

[0154] The prosthesis 102 may comprise a rim 130 configured to abut the side surface 206 of the mounting plate 200. The rim 130 bounds the inner surface 106 along its periphery. The rim 130 may project substantially perpendicularly away from the inner surface 106. For example, the rim 130 may project 1 mm away from the inner surface 106. The rim 130 may be configured to abut the side surface 206 of the mounting plate 200 to align the prosthesis 102 with respect to the mounting plate 200 prior to securing the prosthesis 102 to the mounting plate 200.

[0155] When the prosthesis kit 100 is assembled, the rim 130 may surround and cover the side surface 206 of the mounting plate 200. In some examples, the mounting plate 200 may be completely enclosed by the bone 300 and the prosthesis 102 so that none of the mounting plate 200 is exposed to surrounding tissue in use. In other examples, the rim 130 may partially overlap the side surface 206 of the mounting plate 200 (e.g., discontinuously bound the inner surface 106). The rim 130 may prevent the prosthesis 102 from being slid off the mounting plate 200 in a transverse direction (perpendicular to the major axis 308).

[0156] As mentioned previously, the prosthesis 102 may comprise one or more pins 126 which project away from the inner surface 106. In this example, the prosthesis 102 comprises two pins 126 which are located along the first condyle 120 and the second condyle 122 respectively. The pms 126 project perpendicularly away from the inner surface 106 and substantially parallel to a length of the bone 300.

[0157] Each of the second set of apertures 230 of the mounting plate 200 is configured to receive a respective pin 126 of the prosthesis 102. The pins 126 serve to align the prosthesis 102 with respect to the mounting plate 200 and the bone 300 prior to securing the prosthesis 102 to the mounting plate 200. In this example, a length of the pins 126 is greater than a thickness of the mounting plate 200. When the prosthesis 102 is attached to the mounting plate 200, the pins 126 project through the second set of apertures 230 to directly couple the prosthesis 102 to the bone 300. The pins 126 may act to transmit force from the articulating surface 118 of the prosthesis 102 to the bone 300 thereby alleviating stress shielding of the mounting plate 200.

[0158] The prosthesis 102 comprises a polymer material such as a polymer suitable for biomedical applications e.g., polyaryletherketones (PAEK).

[0159] In contrast, the mounting plate 200 may comprise or essentially consist of a metal such as titanium, titanium alloy or a steel alloy. In a preferred embodiment, the mounting plate 200 consists of titanium or a titanium alloy and at least the interior surface 204 of the mounting plate 200 may comprise porous titanium to promote bone growth into the mounting plate 200.

[0160] As the prosthesis 102 is couplable to the mounting plate 200 which is made from a dissimilar material, the different material requirements of these components may be satisfied while minimising manufacturing cost. For example, providing a metal mounting plate 200 may allow for structurally secure fixation of the prosthesis 102 to the bone 300. This may minimise or prevent aseptic loosening caused by movement of the bone 300 relative to the prosthesis kit 100 at the resected surface. In contrast, the prosthesis 102 may consist of a single piece of integrally molded polymer. Utilising polymer materials in the prosthesis 102 may be beneficial, eliminating or ameliorating the perceived feeling of cold associated with metallic prostheses and the pain associated therewith. It may be advantageous for at least the articulating surface 118 of the prosthesis 102 to be made from polymer to absorb shock associated with external loading of the joint.

[0161] In other examples, only part of the prosthesis 102 may be polymeric. For example, the clips 108 may comprise a polymer while the body 104 comprises a different material such as a polymer having a greater stiffness or a metal. During assembly, the body 104 of the prosthesis 102 is linearly translated towards the mounting plate 200, in a direction substantially parallel to the major axis 308 of the bone 300. For example, the prosthesis kit may be hammered (downwards in FIG. 5) towards the mounting plate 200. The clips 108 on either side 112, 116, of the body 104 resiliently deflect outwards over the exterior surface 202 of the mounting plate 200. When the clips 108 reach the mating surfaces 208 of the mounting plate 200, they snap back inwards, latching onto the mating surfaces 208 to couple the prosthesis 102 to the mounting plate 200.

[0162] The mounting plate 200 may have a higher stiffness than the polymer material of the prosthesis 102. In this way, the prosthesis 102 deforms in preference to the mounting plate 200 when the prosthesis 102 is coupled to the mounting plate 200. For example, the mounting plate 200 may comprise or essentially consist of a metal such as titanium. The inner surface 106 of the prosthesis 102 may be sized slightly smaller than the exterior surface 202 of the mounting plate 200 so that when the prosthesis kit 100 is assembled, the prosthesis 102 applies a compressive force to the mounting plate 200. Such designed misfit may further secure the prosthesis 102 to the mounting plate 200.

[0163] The thickness of the mounting plate 200 may be selected to withstand the compressive force of the prosthesis 102 during and after assembly, without deflecting. This may ensure that the compressive force from the prosthesis 102 is not transferred to the bone 300.

[0164] Coupling the prosthesis 102 to the mounting plate 200 rather than coupling the prosthesis 102 directly to the bone 300, ensures external loads applied to the prosthesis 102 during use can be spread over the terminal end 302 of the bone 300. Were the clips 108 instead directly coupled to the bone 300, they may act as stress concentrators which could further degrade the bone 300 at the connection sites thereby risking detachment of the prosthesis 102. As the prosthesis kit 100 is designed for indirect attachment of the prosthesis 102 to the bone 300, the prosthesis 102 can be more easily replaced without damaging the bone 300. Articulating surfaces 118 may wear over the lifetime of the prosthesis 102. If and when the prosthesis 102 requires replacement, the prosthesis 102 can be replaced with a new similar prosthesis to be mounted on the existing mounting plate 200. This may be beneficial in view of existing implants which couple directly to the bone 300 and typically require extensive bone 300 excision to remove the implant and any bone cement. As such, the prosthesis kit 100 may have an improved lifetime and, where replacement is required, be replaced using less invasive means than previously possible.

[0165] In some embodiments, one or more recesses (not shown) may be provided in the mounting plate 200 for accommodating the clips 108, each recess defining one of the mating surfaces 208. In the example shown in FIG. 5, no such recesses are provided and the clips 108 are positioned at terminal ends of the body 104 to engage the side surface 206 of the mounting plate 200 when the prosthesis kit 100 is assembled. Providing recesses in the mounting plate 200 may reduce the structural integrity of the mounting plate 200. As such, where recesses are provided in the mounting plate 200, the thickness of the mounting plate 200 may be greater to ensure sufficient structural integrity. Where no recesses are provided in the mounting plate 200, the minimum required thickness of the mounting plate 200 is reduced. Such a reduced thickness mounting plate 200 may be beneficial, limiting stress shielding of the bone 300.

[0166] FIG. 6A to FIG. 6C provide three different views of the prosthesis 102. In these figures, the prosthesis 102 is shown in isolation from other components of the prosthesis kit 100, so that the structure of the prosthesis 102 is not obscured. As shown, each of the clips 108 are disposed on a peripheral edge 132 of the prosthesis 102 which bounds the inner surface 106.

[0167] Two first clips 110 are provided on the first side 112 of the prosthesis 102 for coupling to the rear 212 of the mounting plate 200. The two first clips 110 are located at rear ends 134 of the first condyle 120 and the second condyle 122 respectively. The first clips 110 may be shaped to securely fix the prosthesis 102 to the mounting plate 200 during axial loading, parallel to the major axis 308 (as shown by first arrow 601), and during transverse loading, perpendicular to the major axis 308 (shown by second arrow 602). At least one of the clips 108 may be curved. This may prevent the prosthesis 102 from being slid off the mounting plate 200 in a transverse direction. In this example, each of the first clips 110 consists of a rib, m particular an arcuate rib. The curvature of the arcuate ribs matches the curvature of the peripheral edge 132 at that location i.e., the arcuate rib at the first condyle 120 follows a profile of the first condyle 120 while the arcuate rib at the second condyle 122 follows a profile of the second condyle 122.

[0168] The at least one second clip 114 is arranged at the second side 116 of the prosthesis 102 for coupling to the second mating surface 214 at the front 216 of the mounting plate 200. In this example, one second clip 114 is provided. The second clip 114 is located at the anterior hub 124 and spans front ends 136 of the first and second condyle 122, opposite the rear ends 134.

[0169] As shown m FIG. 5, at the front 216 of the mounting plate 200 the side surface 206 comprises a flat portion 238 which defines the second mating surface 214. The at least one second clip 114 is shaped to mate with the second mating surface 214. When the second clip 114 engages with the second mating surface 214 of the mounting plate 200, a portion of the anterior hub 124 extends beyond the mounting plate 200.

[0170] In other examples, the side surface 206 at the front 216 of the mounting plate 200 may comprise two undulations (not shown) which follow the profile of the first condyle 120 and the second condyle 122 respectively. In such examples, two or more second clips 114 may be provided at the second side 116 of the prosthesis 102 for mating with the two undulations. For example, one second clip 114 may be located at the front end 136 of the first condyle 120 and another second clip 114 located at the front end 136 of the second condyle 122.

[0171] FIG. 7 shows a cross-sectional view of the assembled prosthesis kit 100. As shown, each of the clips 108 comprise a leading surface 138 and a trailing surface 140.

[0172] In use, each of the the trailing surfaces 140 abut a respective one of the mating surfaces 208 of the mounting plate 200. Trailing surfaces 140 and mating surfaces 208 may be angled to inhibit decoupling of the prosthesis 102 from the mounting plate 200. For example, as shown in FIG. 7, the mating surfaces 208 may be perpendicular to each of the exterior surface 202 and the interior surface 204. In other examples, the mating surfaces 208 may make an acute angle with the interior surface 204 and / or make an obtuse angle with the exterior surface 202. Trailing surfaces 140 of the clips 108 are configured to be coplanar with and abut the respective mating surfaces 208 of the mounting plate 200 when the prosthesis kit 100 is assembled. Angling the mating surfaces 208 of the mounting plate 200 and the trailing surfaces 140 of the clips 108 in this way may inhibit decoupling of the prosthesis 102 from the mounting plate 200, ensuring the prosthesis 102 remains securely attached to the mounting plate 200 during use.

[0173] The leading surfaces 138 of the clips 108 may be shaped to aid sliding of the prosthesis 102 down onto the mounting plate 200. For example, the leading surface 138 of each clip 108 may make an acute angle with the trailing surface 140 of that clip 108. This may minimise the force required to connect the prosthesis 102 to the mounting plate 200 during assembly, reducing the likelihood of misalignment.

[0174] For all or some clips 108, the leading surface 138 and the trailing surface 140 may be contiguous, as shown by the first clip 110 in FIG. 7. Alternately, the leading surface 138 and the trailing surface 140 of any clip 108 may not be contiguous. For example, the leading surface 138 may be separated from the trailing surface 14 as shown by the second clip 114 in FIG. 7.

[0175] FIG. 8 shows a flow diagram illustrating a method of fixing a prosthesis to a bone using a mounting plate. In this example, the prosthesis, mounting plate and bone are the prosthesis 102, mounting plate 200 and bone 300 described in relation to FIG. 1 to FIG. 7.

[0176] A first step 801 of the method 800 involves attaching the mounting plate 200 to the bone 300. For example, the mounting plate 200 may be fixedly attached to the bone 300 by way of one or more fasteners 232 such as bone screws. Each of the fasteners 232 may be received in a respective one of the first set of apertures 228 and be screwed into the bone 300. In some examples, one or more pilot holes may be drilled in the bone 300 for receiving a respective fastener 232. The pilot holes may be positioned to align with a respective one of the first set of apertures 228. Such pilot holes may be drilled prior to fitting the mounting plate 200 to the bone 300 or after the mounting plate 200 has been placed on the bone 300 but before the mounting plate 200 has been secured to the bone 300 by way of the fasteners 232.

[0177] A second step 802 of the method 800 includes coupling the prosthesis 102 to the mounting plate 200. When the prosthesis is coupled to the mounting plate 200, clips 108 of the prosthesis 102 engage with mating surfaces 208 of the mounting plate 200 to form a snap fit connection between the clips 108 and the mating surfaces 208 of the mounting plate 200.

[0178] The second step 802 may involve translating the body 104 towards the mounting plate 200 thereby resiliently deflecting the clips 108 outwards over an exterior surface of the mounting plate. For example, the prosthesis 102 may be hammered along the major axis 308 towards the mounting plate 200 to mount the prosthesis 102 to the mounting plate 200. When the prosthesis 102 is coupled to the mounting plate 200, the clips 108 latch onto the mating surfaces 208 of the mounting plate 200 to couple the prosthesis 102 to the mounting plate 200. In this example, the first step 801 is completed before the second step 802. In other examples, the second step 802 may be completed before the first step 801. For example, the prosthesis 102 may be coupled to the mounting plate 200 by way of the snap fit connection and then the mounting plate attached to the bone 300 e.g., by hammering the mounting plate 200 onto the terminal end 302 of the bone 300. For example, the mounting plate 200 may comprise one or more nails projecting from the interior surface 204 for fixedly attaching the mounting plate 200 to the bone.

[0179] The method 800 may further comprise a preceding step 810 which precedes the first step 801. The preceding step 810 may involve resecting a portion of the bone 300 to form a resected surface 304 configured to receive the mounting plate 200. Resecting the bone may remove damaged bone surface unsuitable for securely fastening the mounting plate 200 thereto.

[0180] Where the prosthesis 102 comprises one or more pins 126 for aligning the prosthesis 102 with respect to the mounting plate 200, the mounting plate 200 comprises a second set of apertures 230 for receiving the one or more pins. In such an example, the preceding step 810 or the first step 801 may further include drilling one or more holes 306 in the bone 300 each for receiving a respective one of the one or more pins 126. Drilling one or more holes 306 may be completed before or after the bone 300 is resected to form the resected surface 304. In some examples, the holes 306 may be drilled after the mounting plate 200 has been attached to the bone 300.

[0181] Features described in conjunction with a particular aspect, embodiment or example of the disclosure 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 the method 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 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 the method so disclosed.

Claims

1. A prosthesis kit for fixing a prosthesis to a bone, comprising:a mounting plate for coupling to the bone;a prosthesis for coupling to the mounting plate, comprising a body shaped to at least partially cover the mounting plate, and clips disposed on opposite sides of the body for engaging with mating surfaces of the mounting plate;wherein the prosthesis is configured to couple to the mounting plate by way of a snap fit connection between the clips and the mating surfaces of the mounting plate.

2. The prosthesis kit of claim 1, wherein the mounting plate comprises an interior surface for engaging with an outer surface of the bone, optionally wherein the mounting plate is configured to at least partially surround a terminal end of the bone.

3. The prosthesis kitof claim 2, wherein the mounting plate further comprises an exterior surface, and wherein an inner surface of the prosthesis is shaped conformally to the exterior surface of mounting plate.

4. The prosthesis kit of claim 3, wherein the prosthesis is configured such that when the body is linearly translated towards the mounting plate, the clips resiliently deflect outwards over the exterior surface of the mounting plate until the clips latch onto the mating surfaces of the mounting plate to couple the prosthesis to the mounting plate.

5. The prosthesis kit of any one of claims 1 to 4, wherein the prosthesis comprises a prosthetic joint comprising an articulating surface shaped to interface with an opposing surface of a neighbouring joint, optionally wherein the prosthesis comprises a femoral implant.

6. The prosthesis kit of any preceding claim, wherein the mounting plate comprises a side surface which surrounds the mounting plate and comprises the mating surfaces such that when the prosthesis is coupled to the mounting plate, the clips engage the side surface of the mounting plate.

7. The prosthesis kit of any preceding claim, wherein the mounting plate has a greater stiffness than the prosthesis such that the prosthesis deflects as it is coupled to the mounting plate,optionally wherein the mounting plate comprises or essentially consists of a metal such as titanium, and optionally wherein the prosthesis comprises or essentially consists of a polymer.

8. The prosthesis of any preceding claim, wherein the prosthesis comprises one or more pins for insertion into one or more corresponding recesses in the bone and wherein the mounting plate comprises one or more apertures configured to receive a respective pin when the prosthesis is coupled to the mounting plate.

9. A prosthesis for coupling to a mounting plate attached to a bone such that the prosthesis is fixed to the bone, the prosthesis comprising:a body shaped to at least partially cover the mounting plate; andclips disposed on opposite sides of the body for engaging with mating surfaces of the mounting plate when the prosthesis is coupled to the mounting plate.

10. The prosthesis of claim 9, wherein the prosthesis comprises a prosthetic joint comprising an articulating surface shaped to interface with an opposing surface of a neighboring joint, optionally wherein the prosthesis comprises a femoral implant.

11. The prosthesis of claim 9 or 10, wherein each of the clips are disposed on a peripheral edge of the prosthesis.

12. The prosthesis of any one of claims 9 to 11, wherein at least one of the clips comprises a rib shaped protrusion.

13. The prosthesis of claim 12, wherein at least one of the rib shaped protrusions are curved.

14. The prosthesis of any one of claims 10 to 14, wherein the body comprises a first condyle and a second condyle which branch from an anterior hub to form a curved V-shape and wherein the clips comprise a first clip located at the first condyle, a second clip located at the second condyle and a third clip located at the anterior hub.

15. The prosthesis of claim 14, wherein the first clip comprises a curved rib which follows a profile of the first condyle and the second clip comprises a curved rib which follows a profile of the second condyle.

16. The prosthesis of any one of claims 10-16, wherein the prosthesis comprises or essentially consists of a polymer material, optionally wherein the prosthesis comprises polyaryletherketones (PAEK), such as polyetheretherketone (PEEK) or polyetherketoneketone (PEKK), polyphenylene sulphide (PPS), polyetherimide (PEI), polycarbonate (PC), polyethylene terephthalate (PET), polyamide (PA), poly(methyl methacrylate) or a combination thereof.

17. The prosthesis of any one of claims 10-17, wherein each of the clips comprises a leading surface and a trailing surface, the trailing surfaces being shaped to inhibit decoupling of the prosthesis from the mounting plate.

18. The prosthesis of any one of claims 10-18, wherein the prosthesis is configured such that when the body is linearly translated in a first direction towards the mounting plate, the clips resiliently deflect outwards over the exterior surface of the mounting plate until the clips latch onto the mating surfaces of the mounting plate to couple the prosthesis to the mounting plate.

19. The prosthesis of any one of claims 10-19, further comprising one or more pins for insertion into one or more corresponding recesses in the bone.

20. The prosthesis of any one of claims 10-20, wherein an inner surface of prosthesis is substantially smooth.

21. A mounting plate for attaching a prosthesis to a bone, the mounting plate being attachable to the bone and comprising mating surfaces for coupling with clips of the prosthesis to form a snap fit connection.

22. The mounting plate of claim 21, wherein the mounting plate comprises an interior surface for engaging with an outer surface of the bone.

23. The mounting plate of claim 22, wherein the mounting plate is configured to at least partially surround a terminal end of the bone.

24. The mounting plate of claim 21 or 22, wherein the mounting plate comprises two arms: a first arm for engaging with a medial condyle of the bone; and a second arm for engaging with a lateral condyle of the bone.

25. A method of fixing a prosthesis to a bone comprising the steps of:attaching a mounting plate to the bone;coupling the prosthesis to the mounting plate, the prosthesis comprising a body shaped to at least partially cover the mounting plate and clips disposed on opposite sides of the body for engaging with mating surfaces of the mounting plate to form a snap fit connection between the clips and the mating surfaces of the mounting plate.30

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