An orthopaedic implant

Abstract

An orthopaedic implant (10) including: a frame (100) for interfacing with bone or bone tissue, the frame (100) including: a central cavity (105) adapted to contain osteogenic material; and at least one opening (110) providing a dedicated delivery point for insertion of osteogenic material into the central cavity (105); and a plurality of panels (160) supported by the frame (100) and adapted to be in direct contact with the bone or bone tissue, wherein each panel (160) has a porous surface geometry, and wherein each panel (160) has a curved arrangement to provide the implant (10) with a substantially spherical shape, with the plurality of panels (160) being arranged to surround the central cavity (105) to provide a closed system.

Description

AN ORTHOPAEDIC IMPLANTFIELD

[0001] The present invention generally relates to an orthopaedic implant.

[0002] The invention has been developed primarily in relation to implants for treating bone defects in the lower limb areas, and will be described hereinafter with reference to these applications. However, it will be appreciated that the invention is not limited to this particular field of use, and may also be employed in orthopaedic applications in other limb areas.BACKGROUND

[0003] Bone defects in the lower limb areas, such as the hindfoot and tibia, commonly arise from various factors such as trauma, unsuccessful surgical procedures involving ankle replacements and fusions, bone diseases such as avascular necrosis, osteomyelitis, and Charcot arthropathy. These defects present significant challenges for patients, including prolonged disability, pain, discomfort, and the risk of amputation.

[0004] Conventional treatment options for managing large defects include bone transport, large allograft struts, femoral heads, and osteomyocutaneous flaps of the fibula. However, such treatment options often lead to non-union, necessitate multiple lengthy surgeries, and require prolonged external fixation, yielding inconsistent outcomes.

[0005] Known implants for treating bone defects are typically expensive and demand extensive preoperative planning. Additionally, such implants may not adequately address soft tissue constraints, accommodate irregular anatomical geometries, or provide secure graft containment architecture, and variable size options may not be available during surgery.SUMMARY

[0006] It is an object of the present invention to substantially overcome, or at least ameliorate, one or more of the disadvantages of existing arrangements, or at least provide a useful alternative to existing arrangements.

[0007] There is disclosed herein an orthopaedic implant including: a frame for interfacing with bone or bone tissue, the frame including: a central cavity adapted to contain osteogenic material; and at least one opening providing a dedicated delivery point for insertion of osteogenic material into the central cavity; and a plurality of panels supported by the frame and adapted to be in direct contact with the bone or bone tissue, wherein each panel has a porous surface geometry, and wherein each panel has a curved arrangement to provide the implant with a substantially spherical shape, with the plurality of panels being arranged to surround the central cavity to provide a closed system.

[0008] In some embodiments, the panels are integrally formed with the frame as a unified system.

[0009] In some embodiments, the panels extend from the frame so as to be flush with the surface of the frame, thereby providing a continuous spherical enclosure of the central cavity.

[0010] In some embodiments, the at least one opening is provided as two openings located on a hemisphere of the frame.

[0011] In some embodiments, a first of the two openings is located on an opposite side of the frame to a second of the two openings.

[0012] In some embodiments, the frame includes a plurality of elongated and interconnected arm portions defining the central cavity.

[0013] In some embodiments, some of the arm portions are arranged to extend in a first direction between an upper portion and a lower portion of the frame.

[0014] In some embodiments, some of the arm portions are arranged to extend in a second direction, with the second direction being transverse to the first direction.

[0015] In some embodiments, each arm portion of the frame has a curved arrangement to provide the frame with a substantially spherical shape, and wherein the at least one opening extends through a least one of the arm portions to be in communication with the central cavity.

[0016] In some embodiments, the porous surface geometry of each panel includes a plurality or network of non-uniform pores, wherein the pores extend through the panel to be in communication with the central cavity.

[0017] In some embodiments, the plurality or network of non-uniform pores forms a lattice structure.

[0018] In some embodiments, the non-uniform pores are configured in a randomised or biomimetic manner.

[0019] In some embodiments, one or more of the panels has a graded or hierarchical porosity of between approximately 60 and 80%.

[0020] In some embodiments, the porosity is approximately between approximately 60 and 70%.

[0021] In some embodiments, the porosity is approximately 63%.

[0022] In some embodiments, the porous surface geometry is macroporous, in which the panel has pore sizes ranging from between approximately 300 to 3,000 microns.

[0023] In some embodiments, the pore sizes are approximately 1,400 microns on average.

[0024] In some embodiments, the porous surface geometry is microporous, in which the panel has pore sizes ranging from between approximately 15 to 60 microns.

[0025] In some embodiments, the porous surface geometry is nanoporous.

[0026] In some embodiments, the at least one opening is located at an interface between two of the panels.

[0027] In some embodiments, the frame further includes one or more implant holder points, wherein each implant holder point includes at least one opening providing access to the central cavity.

[0028] In some embodiments, the implant is formed from a material having a modulus of elasticity approximating that of native bone.

[0029] In some embodiments, the implant has a diameter of between approximately 32 and 40 mm, and the central cavity is configured to accommodate a volume of osteogenic material ranging from between approximately 5 and 10 cubic centimetres.

[0030] In some embodiments, the orthopaedic implant further includesa lumen extending through the central cavity of the frame and along a central axis thereof, wherein the lumen is adapted to provide access for insertion of an intramedullary nail therethrough.

[0031] In some embodiments, n the lumen has a diameter sized to receive a standard intramedullary nail.

[0032] There is also disclosed herein an adaptor sleeve for the orthopaedic implant as described above, the adaptor sleeve configured to be received in the lumen and including a collar and a body extending from the collar, the body including an inner bore sized to receive an intramedullary nail having a smaller diameter than the standard intramedullary nail, and the collar being adapted to engage an lower portion of the frame.

[0033] There is also disclosed herein a trial implant configured to match the orthopaedic implant as described above.BRIEF DESCRIPTION OF THE DRAWINGS

[0034] For a more complete understanding of the present invention, exemplary embodiments of the invention are explained in more detail in the following description with reference to the accompanying drawing figures, in which like reference signs designate like parts and in which:

[0035] Figure l is a schematic side view of an orthopaedic implant according to one embodiment;

[0036] Figure 2 is a schematic top view of the orthopaedic implant shown in Figure 1;

[0037] Figure 3 is a schematic isometric view of a frame of the orthopaedic implant shown in Figure 1;

[0038] Figure 4 is a schematic front view of an orthopaedic implant shown in Figure 1, with an example of a surface finish;

[0039] Figure 5 is a schematic front view of the orthopaedic implant shown in Figure 4;

[0040] Figure 6 is a schematic cross-sectional view of the orthopaedic implant shown in Figure 4;

[0041] Figure 7 is a schematic isometric view of a trial implant according to one embodiment;

[0042] Figures 8 and 9 are schematic side views of the trial implant shown in Figure 7;

[0043] Figure 10 is a schematic front view of the trial implant shown in Figure 7;

[0044] Figure 11 is a schematic cross-sectional view of the trial implant along line A-A of Figure 10; and

[0045] Figure 12 is a schematic perspective view of an adaptor sleeve for an orthopaedic implant according to one embodiment.DETAILED DESCRIPTION

[0046] In Figures 1 and 2 of the accompanying drawings, there is schematically depicted an embodiment of an orthopaedic implant 10. For the purposes of this specification, the orthopaedic implant 10 and various alternative embodiments will be described for use in treating lower limb defects, such as defects in the tibia and talar bones. It will, however, be appreciated that the orthopaedic implant 10 and various alternative embodiments may be adapted for treating bone defects in other areas of the body. In some examples, the orthopaedic implant 10 and various alternative embodiments may be used for treating upper limb defects.

[0047] The orthopaedic implant 10 includes a frame (or cage or truss structure) 100 for interfacing with bone or bone tissue. The frame 100 may serve as a scaffold to facilitate boneingrowth and osseointegration. The frame 100 may be constructed by 3D printing from an alloy, alloy compound material, composite material, or the like. In some embodiments, the frame 100 may be constructed from a titanium alloy metal material. It will, however, be appreciated that the frame 100 may be constructed using any other suitable method and from any other suitable material, depending on the design requirements of the implant 10 and / or the implant site. Generally, and as will be discussed in further detail below, it is envisaged that the various components of the implant 10 are to be constructed from a material having a modulus of elasticity approximating that of native bone.

[0048] Referring to Figure 3, the frame 100 includes a central cavity 105 and at least one opening 110 for providing access to the central cavity 105, with the central cavity 105 being adapted to contain osteogenic material (autograft or allograft material). Autograft material, in particular, is rich in native growth factors such as platelet-derived growth factor (PDGF), which plays a key role in early bone healing by stimulating osteoprogenitor chemotaxis, cell proliferation, angiogenesis, and extracellular matrix synthesis. It will be appreciated that the at least one opening 110 may provide a dedicated access / delivery point (graft port) and be strategically positioned to facilitate insertion of osteogenic material into the central cavity 105. The at least one opening may at least allow a surgeon to introduce the osteogenic material directly into central cavity 105 without requiring disassembly or excessive manipulation of the implant 10 during surgery. As such, the at least one opening 110 may allow for the retention of graft material within the central cavity 105 whilst at least permitting cellular migration and vascular infiltration necessary for bone healing. In some embodiments, the at least one opening 110 may be provided separately from a lumen of the implant 10, as will be described in further detail below.

[0049] In the depicted embodiment, the frame 100 includes four openings 110 (collectively openings 110a, 110b, 110c, 1 lOd) that provide access to the central cavity 105, with two of the openings 110a and 110b located on an upper hemisphere or section 111 of the frame 100 and another two of the openings 110c and 1 lOd located on a lower hemisphere or section 112 of the frame 100. The two openings 110a and 110b on the upper hemisphere 111 may oppose each other (i.e. locatable on opposite sides of a central axis 135 of the frame 100) and likewise, the two openings 110c and 1 lOd on the lower hemisphere 112 may oppose each other. For example, a first 110a of the two openings on the upper hemisphere 111 may be located on a firstside 113 of the frame 100, and a second 110b of the two openings may be located on a second side 114 of the frame, with the first side 113 being opposite the second side 114. The positioning of openings 110 on opposing sides 113, 114 within the same hemisphere may at least provide a built-in feedback mechanism: for example, graft material may be inserted into one of the openings 110 on the upper hemisphere, and once graft material begins to emerge from the opposing opening 110 on the upper hemisphere, it provides a visual confirmation that the central cavity 105 has been fully packed to indicate that the entire upper hemisphere is completely filled. Accordingly, the arrangement of the openings 110 may at least provide a real-time and controlled visual confirmation of adequate graft delivery, minimising the risk of underfilling, and improving consistency across procedures. By enabling a controlled and complete graft fill, the implant 10 may at least maximise the biological potential of the implanted material, promoting a dense, well-distributed scaffold of autograft or allograft that supports angiogenesis, osteoconduction, and osseointegration. This arrangement may thus contribute effectively to the healing environment, thereby improving the likelihood of robust fusion and long-term implant success.

[0050] It will be understood that the use of the terms “upper” and “lower” is intended to be understood in relation to the orientation of the implant shown in the accompanying drawings, and not to place any limitations on the orientation of the implant at an actual implant site. It will also be appreciated that the number and / or configuration of the openings 110 are not necessarily limited to the number and / or configuration as shown in the drawings or described above, and may be adjusted depending on the design requirements of the implant 10 and / or the implant site. In some embodiments, the frame 100 may include less than four openings 110. In other embodiments, the frame 100 may include more than four openings 110.

[0051] As best shown in Figure 3, the frame 100 may include a plurality of interconnected arm portions 115 which define the central cavity 105. The arm portions 115 may thus at least partially surround or form the boundaries of the central cavity 105. Each arm portion 115 may have a curved arrangement to provide the frame 100 with a substantially spherical or spheroid shape to at least maximise the contact or surface area coverage at the bone-implant interface. In the interest of clarity, not all arm portions 115 are accorded a reference numeral in the accompanying drawings. It will be understood that the arm portions 115 of the frame 100 may be the generally elongated portions of the frame 100. In the depicted embodiment, some of thearm portions 115 may be arranged to extend in a first (longitudinal) direction between an upper portion 120 and a lower portion 125 of the frame 100, and some of the arm portions 115 may additionally be arranged to extend in a second direction, with the second direction being transverse to the first direction. As such, an arm portion 115 that extends in the first direction may cross-connect with an arm portion 115 that extends in the second direction. An arm portion 115 that extends in the second direction may provide the connection between two of the arm portions 115 that extend the first direction. It will be appreciated that the number and / or configuration of the arm portions 115 are not necessarily limited to the number and / or configuration as shown in the drawings or described above, and may be adjusted depending on the design requirements of the implant 10 and / or the implant site. For example, the frame 100 may include any number of arm portions 115 and the overall geometry thereof may be adjusted depending on the design requirements of the implant 10 and / or the implant site.

[0052] It is envisaged that the implant 10 may be provided in a range of predetermined or off- the-shelf sizes / diameters. Providing the implant 10 with readily available modular sizing options may at least enable intraoperative flexibility by allowing for real-time intraoperative adjustment. Having a range of predetermined or off-the-shelf sizes may also at least reduce or altogether eliminate the delays associated with custom implant manufacturing. To this end, the frame 100 (and / or the implant 10 as a whole) may have a predetermined outer diameter of between approximately 28 and 44 mm. In some embodiments, the frame 100 and / or the implant 10 may have a predetermined outer diameter of between approximately 32 and 40 mm. With these predetermined outer diameters, the central cavity 105 may be configured to accommodate a volume or volumes of graft (osteogenic material) ranging from between approximately 5 and 10 cubic centimetres (CCs), depending on the implant size / diameter. For example, an implant 10 having a 36 mm diameter may hold approximately 7.5 CC of graft material, enabling treatment of larger bone defects and supporting complete biological fill across the central cavity 105.

[0053] Each arm portion 115 may have a length of between approximately 0.5 and 20 mm, a width of between approximately 0.5 and 3 mm, and a depth or thickness of between approximately 0.5 and 2 mm. In some embodiments, each arm portion 115 may have a length of approximately 20 mm, a width of approximately 2 mm, and a depth or thickness ofapproximately 1 mm. It will be understood that the dimensions of each arm portion 115 may depend on the required overall size of the implant 10.

[0054] The at least one opening 110 may extend through one of the arm portions 115 of the frame 100 to be in communication with the central cavity 105. As discussed above, the frame 100 may include any number of openings 110 that provide access to the central cavity 105, and the frame 100 may also include any number of arm portions 115 extending in a longitudinal and / or transversal direction. As such, it will be understood that in some embodiments, not all of the arm portions 115 will include or define an opening 110. In the example shown, four of the longitudinally-extending arm portions 115 each include an opening to provide two openings 110a, 110b on the upper hemisphere 111 and two openings 110c, 1 lOd on the lower hemisphere 112. Each opening 110 may have a circular shape or cross-section and may have a diameter of between approximately 8 and 10 mm. In some embodiments, each opening 110 may have a diameter of approximately 10 mm. It will be understood that the dimensions of each opening 110 may depend on the required overall size of the implant 10, noting that in at least an embodiment, each opening 110 should be small enough to retain graft material yet sufficiently open to permit cellular migration, osteoblast and osteoclast activity, and vascular infiltration.

[0055] The implant 10 may further include a lumen 130 that is formed in or extends through the central cavity 105 of the frame 100. In the depicted embodiment, the lumen 130 extends along the central axis 135 of the frame 100 between the upper portion 120 and the lower portion 125. The lumen 130 may be defined by a central cylindrical wall 140 of the frame 100. One or more of the arm portions 115 may be connected to (or integrally formed with) the cylindrical wall 140 (for example, at or around the upper portion 120 and the lower portion 125 of the frame 100). It will be appreciated that the lumen 130 may be adapted to provide access for insertion of an intramedullary nail or rod through the frame 100 and the overall implant 10. The lumen 130 may have a circular cross-section and may have a diameter of between approximately 10 and 20 mm. In some embodiments, the lumen 130 may have a diameter of between approximately 10 and 16 mm. In some embodiments, the lumen 130 may have a diameter of between approximately 13 and 14 mm. It will be understood that the dimensions of the lumen 130 may depend on the required overall size of the implant 10. It is envisaged that in some embodiments, the lumen 130 may be provided as a universally-sized lumen adapted to accommodate a standard intramedullary nail (understood to be approximately 13 mm in diameter) together withan adaptor sleeve system for smaller nails (e.g. 11 mm, 10 mm, 9 mm) as will be described in further detail below.

[0056] The frame 100 may further include one or more implant holder points 150. Each implant holder point 150 may include at least one opening 155 providing access to the central cavity 105. The at least one opening 155 may be threaded or unthreaded to accommodate a surgical tool. The one or more implant holder points 150 may be provided on one or more of the arm portions 115 of the frame 100, whereby the at least one opening 155 is formed in or extends through the arm portion 115. In the depicted embodiment, the frame 100 includes two implant holder points 150. As discussed above, the frame 100 may include any number of arm portions 115. As such, it will be understood that in some embodiments, not all of the arm portions 115 will include or define an implant holder point 150. In the depicted embodiment, each implant holder point 150 includes a threaded opening and an unthreaded opening located adjacent either side of the threaded opening. The threaded opening may have a circular cross-section and may have a diameter of between approximately 3 and 5 mm. The unthreaded openings may each have a circular cross-section and may have a diameter of between approximately 2.5 and 3 mm. In some embodiments, the unthreaded opening may have a diameter of approximately 2.7 mm. It will, however, be appreciated that the number and / or configuration of the implant holder points 150 are not necessarily limited to the number and / or configuration as shown in the drawings or described above, and may be adjusted depending on the design requirements of the implant 10 and / or the implant site. It will also be understood that the dimensions of each opening 155 may depend on the required overall size of the implant 10.

[0057] Returning to Figures 1 and 2, the orthopaedic implant 10 further includes a plurality of panels (or outer members or coverings) 160 supported by the frame 100. The panels 160 are adapted to be in direct contact with the bone. The panels 160 may be integrally formed with the frame 100 (e.g. by 3D printing the panels 160 and the frame 100 as a unified or singular system). In the same manner, the panels 160 may be integrally formed with the plurality of arm portions 115. The panels 160 may extend from the frame 100 along an outer surface so as to be flush with the outer surface of the frame 100. The arrangement of the panels 160 and the frame 100 may thereby provide an uninterrupted or continuous spherical enclosure of the central cavity 105. It will be appreciated that this arrangement may also at least maximise the contact or surface area coverage of the panels 160 with the bone to facilitate bone-implant integration.With the arrangement of the panels 160, the implant 10 may also be provided as a closed system, which has higher ongrowth and ingrowth potential relative to open systems such as traditional truss or lattice systems. In other embodiments, the panels 160 may be separately formed from the frame 100 or the plurality of arm portions 115. In the depicted embodiment, the implant 10 includes eight panels 160 supported by the frame 100, with four of the panels 160 supported by the upper hemisphere or section 111 of the frame 100 and another four of the panels 160 supported by lower hemisphere or section 112 of the frame 100. It will, however, be appreciated that the number and / or configuration of the panels 160 are not necessarily limited to the number and / or configuration as shown in the drawings or described above, and may be adjusted depending on the design requirements of the implant 10 and / or the implant site. In some embodiments, the implant 10 may include less than eight panels 160. In other embodiments, the implant 10 may include more than eight panels 160.

[0058] Each panel 160 may have a curved arrangement to provide the implant 10 with a substantially spherical or spheroid shape to at least maximise the contact or surface area coverage at the bone-implant interface. Each panel 160 may have an overall shape that is curved or may include one or more curved surface portions.

[0059] Each panel 160 may have a porous surface geometry including a plurality or network of non-uniform pores 165 forming a lattice structure, as shown in the non-limiting example of Figures 4 to 6. It will be understood that the non-uniform pores 165 are configured in a randomised or biomimetic manner, thereby being distinct from a conventional mesh structure, which typically includes openings having a uniform shape or size throughout the mesh. The pores 165 may extend through the panel 160 to be in communication with the central cavity 105 and may also be provided continuously across the surface of the panel 160. When the panels 160 are integrally formed with or extend from the frame 100, the plurality or network of non- uniform pores 165 may also extend continuously across the surface of the overall implant 10, thereby maximising the contact or surface area coverage of the panels 160 with the bone to facilitate bone apposition and ensuring uninterrupted contact with the bone. The arrangement of the pores 165 may thus at least promote even load distribution and minimise micromotion at the bone-implant interface, which are factors that are understood to be critical in preventing fibrous tissue formation and facilitating early osseointegration.

[0060] Each panel 160 may have a porosity of between approximately 60 and 80 %. In some embodiments, each panel 160 may have a porosity of between approximately 60 and 70 %. In some embodiments, each panel 160 may have a porosity of approximately 63 % continuously across its surface. It is understood that porosity levels within these ranges are superior to conventional open-structured designs, which typically provide only partial surface coverage with large, uniform voids between struts, thus limiting the available surface area for bone ongrowth and reducing the extent of direct implant-bone contact.

[0061] It will be appreciated that the surface geometry of each panel 160 may incorporate graded or hierarchical porosity including macroporous (which refers to the pore size(s) in the panel), microporous (which refers to a surface roughness of the panel), and / or nanoporous (which may be included for beneficial effects on biofilm and infection resistance). In a macroporous surface geometry, the non-uniform pore sizes may range from between approximately 300 to 3,000 microns. In some embodiments, the average pore size may be approximately 1,400 microns. In a microporous surface geometry, the pore sizes may range from between approximately 15 to 60 microns. The panels 160 may additionally include a surface finish.

[0062] It will be appreciated that the graded or hierarchical porosity of the panels 160 may at least allow for enhanced osteoblast adhesion and extracellular matrix deposition. It is understood that these characteristics may support robust bone ongrowth across the entire surface of the implant 10. With this characteristics, the implant 10 may at least seek to achieve superior initial fixation and promote higher fusion rates, particularly in demanding load-bearing orthopaedic applications. Furthermore, the graded or hierarchical porosity of the panels 160 is designed to be small enough to retain graft material within the implant 10, yet sufficiently open to permit cellular migration, osteoblast and osteoclast activity, and vascular infiltration. This may at least enable a higher density of graft to be securely packed within the implant 10, creating an optimal osteoinductive and osteoconductive environment. Additionally, this secure graft containment may at least promote the localised accumulation of regenerative cytokines, such as PDGF, supporting angiogenesis and driving the full cascade of bone healing, remodeling, and implant stabilisation. This biologically responsive design seeks to enhance the efficiency and success of osseous integration, particularly in large defect or revision scenarios where graft retention is critical.

[0063] Each panel 160 may have a height of between approximately 15 and 20 mm, a width of between approximately 10 and 25 mm, and a depth or thickness of between approximately 1 and 2 mm. In some embodiments, each panel 160 may have a height of approximately 20 mm, a width of approximately 25 mm, and a depth or thickness of between approximately 1.5 and 1.7 mm. It will be understood that the dimensions of each panel 160 may depend on the required overall size of the implant 10.

[0064] As shown in the depicted embodiment, the panels 160 are supported by (or extend from) the frame 100 and are arranged to surround or enclose the central cavity 105 to provide a closed lattice structure or system. It will be appreciated that the closed lattice structure or system may at least provide or facilitate a secure graft containment architecture within the structure of the implant 10. Unlike open lattice designs which lack defined structural boundaries and often allow graft migration or loss, the closed panel -based configuration of the implant 10 may at least prevent escape of graft material, conserving what is often a costly and finite biological resource. The secure graft containment provided by the closed lattice structure or system of the implant 10 may also promote the localised accumulation of PDGF, for example, supporting angiogenesis and driving the full cascade of bone healing, remodeling, and implant stabilisation. This biologically responsive design may at least enhance the efficiency and success of osseous integration, particularly in large defect or revision scenarios where graft retention is critical.

[0065] Furthermore, the closed lattice structure or system of the implant 10 may at least enable a complete circumferential coverage, ensuring that the entire surface of the implant 10 is available for uniform and rapid cellular attachment, osteoblast proliferation, and extracellular matrix deposition. The spherical, closed structure of the implant 10 is also designed to maximise the volume of graft (osteogenic material) contained in the central cavity 105 relative to the external footprint of the implant 10. In other words, the implant 10 may accommodate a higher concentration of osteogenic material to enhance the biological potential of the implant, without increasing its overall size.

[0066] Each panel 160 may be arranged to accommodate access to the central cavity 105. For example, the at least one opening 110 of the frame 100 may be located at an interface between two of the panels 160. Each end opening of the lumen 130 may also be located at an interface between four of the panels 160. The one or more implant holder points 150 may also be located at an interface between two of the panels 160. It will, however, be appreciated that thearrangement of the panels 160 relative to the frame 100 and components thereof is not necessarily limited to the arrangement as shown in the drawings or described above, and may be adjusted depending on the design requirements of the implant 10 and / or the implant site.

[0067] It is envisaged that the implant 10 may include radio-opaque markers (not shown) to allow for intraoperative X-ray assessment of the implant alignment to ensure correct positioning of a trial implant and ultimately the definitive implant. This arrangement may also allow for the correct positioning of the trial implant prior to the insertion of a guidewire for the intramedullary nail or rod through the lumen 130. The intramedullary nail or rod may be passed through the implant 10 so as to provide definitive fixation.

[0068] The material of the frame 100 and panels 160 may have a modulus of elasticity approximating that of native bone, thereby reducing mechanical mismatch (commonly observed with conventional implants). Having a modulus of elasticity closer to that of native bone may also facilitate more natural load transfer across the bone-implant interface, mitigating stress shielding, and promoting physiological bone remodeling. By preserving mechanical stimulation of the surrounding bone, the implant 10 may enhance biological fixation through improved ongrowth and / or ingrowth. This may at least result in superior integration, reduced risk of implant loosening, and improved long-term stability. Unlike conventional implants, which typically utilise high-stiffness lattice or solid metal constructs, the implant 10 intentionally balances structural integrity with biomechanical harmony. The implant 10 may thus allow for durable, load-sharing performance, especially in demanding load-bearing orthopaedic applications.

[0069] An example of a trial implant 200 is shown in Figures 7 to 11. It is envisaged that the trial implant 200 and embodiments thereof may be constructed to match the eventual or definitive implant (e.g. the implant 10 described above) and may thus include one or more of the features discussed above in relation to the implant 10. The trial implant 200 may be formed from a titanium material, for example, and may be sterilised and reused. The trial implant 200 may include a body 202 having a shape and / or size that corresponds to the shape and / or size of the definitive implant. For example, in the embodiment depicted, the body 202 has a substantially spherical or spheroid shape. The body 202 may also have an outer diameter that corresponds to the outer diameter of the definitive implant. As briefly noted above, one or moreradio-opaque orientation markers 205 may be provided at various positions on an outer surface 210 of the body 202 of the trial implant 200.

[0070] Similar to the implant 10, the trial implant 200 may include a lumen 215 that is formed in or extends through a central cavity 220 of the trial implant 200. The lumen 215 may have a diameter that is larger than a diameter of the intramedullary nail or rod. In one example, the lumen 215 may have diameter that is approximately 4 mm larger than a diameter of the intramedullary nail or rod. It will be appreciated that the dimensions of the lumen 215 may be adjusted depending on the design requirements of the trial implant 200 or of the implant 10 itself.

[0071] The trial implant 200 may also include one or more openings 225 providing access to the central cavity 220, and the openings 225 may be threaded. The trial implant 200 may also include one or more radio-opaque horizon markers 230 located adjacent one or more of the associated openings 225 and / or the lumen 215. It will be appreciated that the radio-opaque markers may at least facilitate accurate placement of the trial implant 200, as well as appropriate positioning for the reaming of the canal.

[0072] In Figure 12, there is schematically depicted an optional adaptor sleeve 300 configured for insertion at least partially into the lumen 130 of the frame 100. As discussed above, in some embodiments of the implant 10, the lumen 130 may be provided as a universally-sized lumen adapted to receive or accommodate a standard intramedullary nail (understood to be approximately 13 mm in diameter), and the adaptor sleeve 300 may thus be used to accommodate smaller nails (e.g. 11 mm, 10 mm, 9 mm). For the purposes of this specification, it will be understood that the term “smaller nail” will be used to describe a nail that has a diameter that is smaller relative to a diameter of a standard nail.

[0073] The adaptor sleeve 300 may include a collar or flange 305 and a body 310 extending longitudinally from the collar 305. The body 310 may be formed as hollow cylinder having an inner bore 315 with a diameter Di that corresponds to a diameter of a smaller nail (e.g. 11 mm, 10 mm, 9 mm) to receive the smaller nail. The body 310 may have an outer diameter Dothat corresponds to a diameter of the lumen 130, so as to allow the body 310 to fit snugly or securely within the lumen 130. When the body 310 is inserted into the lumen 130, the central axis 135 of the frame 100 may be aligned with a central longitudinal axis 320 of the adaptor sleeve 300.

[0074] The collar 305 may have an outer diameter that is larger than the outer diameter Doof the body 310. The collar 305 may engage the lower (inferior) portion 125 of the frame 100 around the lumen 130. The collar 305 may thus be included to control insertion depth of the adaptor sleeve 300, ensure proper seating and coaxial alignment of the nail with the implant 10, and / or maintain a snug fit of the adaptor sleeve 300 with the lumen 130.

[0075] The adaptor sleeve 300 may be formed from a material that corresponds to the material of the frame 100. Accordingly, like the frame 100, the adaptor sleeve 300 may be constructed by 3D printing from an alloy or alloy compound material or composite material. In some embodiments, the adaptor sleeve 300 may be constructed from a titanium alloy metal material.

[0076] It will be appreciated that the inclusion of the adaptor sleeve 300 may at least allow for the use of a single implant 10 with a standard lumen diameter whilst providing for compatibility with multiple nail sizes, thereby avoiding the need to manufacture implants 10 with different lumen diameters. This arrangement may also provide intraoperative flexibility, simplify inventory, and preserve load-sharing mechanics between the implant 10 and the intramedullary nail.

[0077] Various forms of the implant and embodiments thereof described above may have one or more of the following advantages. The implant may be supplied as an off-the-shelf, 3D printed alternative to conventional fixed or custom implants. It is understood that such custom implants typically entail high costs, extensive planning, and lengthy production times ranging from 6 to 12 weeks. Moreover, custom implants may not be viable options in all geographic regions. Custom implant sizing may also be difficult to judge due to the inability to estimate the soft tissue constraints. Multiple custom sizes are typically required to be made to account for the variability in soft tissue constraints. Custom implants also typically fail to account for intraoperative variability, particularly soft tissue anomalies, contractures, or unexpected bony defects. In contrast, various forms of the off-the-shelf implant arrangement and embodiments thereof described herein may at least offer flexibility, immediate availability, and modular sizing options conducive to soft tissue closure, which is critical in complex limb salvage scenarios. Furthermore, the availability of an off-the-shelf implant may at least enable single-stage procedures in complex revisions such as total ankle replacements and non-unions, as opposed to the two-stage approach necessitated by the unavailability of the custom implants. The availability of a single stage, off-the-shelf implant may also allow for more immediate treatmentat a lower cost in both elective and urgent cases, decrease potential deconditioning of a patient, and may also allow a patient to have a more rapid return to function. The provision of an off- the-shelf implant may also allow for more modularity and intraoperative flexibility whilst preserving bone stocks, and may also allow for the preservation of soft tissue tension and constraints.

[0078] The spherical or spheroid arrangement of the implant is also understood to be more ideal than other shapes, as it may at least allow for ease of positioning in flexion, extension, varus, and valgus, thereby improving bone preparation and optimising implant placement for superior functional outcomes. The overall implant arrangement may thus enable patients to maintain leg length, alleviate pain, correct deformity and salvage their limbs, ultimately preventing the need for amputations. Furthermore, the spherical or spheroid arrangement of the implant with the panel coverage, combined with the secure graft containment architecture, may at least allow for better accommodation to irregular anatomical geometries. This clinical utility, when considered alongside the other features, further differentiates the implant from conventional arrangements.

[0079] The porous surface geometry may serve as a scaffold to facilitate bone growth and osseointegration, with the porosity promoting both osteointegration and infection resistance. The presence of the various openings or windows may permit the introduction of allograft or autograft materials into the central cavity, with the secure containment promoting localised accumulation of regenerative cytokines such as PDGF, supporting angiogenesis and driving the full cascade of bone healing, remodeling, and implant stabilisation. The porous network may also at least support vascular infiltration, nutrient diffusion, and the migration of osteogenic and remodeling cells, creating a sustained environment for bone regeneration. One or more of the above arrangements described above may thereby promote quicker recovery times compared to existing methods, provide a stable surface conducive to bone ingrowth, and reduce the morbidity associated with donor sites. By combining graft containment, load transfer, and biological integration within a unified structure, the implant may at least foster early mechanical stability, accelerated bone ingrowth, and long-term fixation.

[0080] As discussed above, the implant may be supplied in a range of off-the-shelf sizes and the inclusion of radio-opaque markers may also allow for a series of trial implants and for intra operative assessment of the best size to fit the bone defect whilst ensuring the soft tissues are not compromised. This may also allow for the correct positioning of the trial prior to the insertionof the guidewire for the intramedullary nail or rod. In addition, the availability of trial implants permits accurate bone and soft tissue preparation, facilitating tension-free wound closure, which is a critical requirement in limb salvage procedures, especially around the ankle where the soft tissue envelope is thin and prone to dehiscence, necrosis, and infection. The design of the implant may at least mitigate this risk, enabling better clinical outcomes. It is understood that the surgical method for implantation is reproducible and should be feasible for any experienced orthopaedic surgeon to perform. Accordingly, one or more of the above arrangements described above may at least significantly reduce the operative times required for many patients, streamlining the surgical process, and potentially enhancing overall patient outcomes.

[0081] Although specific embodiments of the invention are illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternative and / or equivalent implementations exist. It should be appreciated that the exemplary embodiment or exemplary embodiments are examples only and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.

[0082] It will also be appreciated that in this document the terms “comprise”, “comprising”, “include”, “including”, “contain”, “containing”, “have”, “having”, and any variations thereof, are intended to be understood in an inclusive (i.e. non-exclusive) sense, such that the process, method, device, apparatus or system described herein is not limited to those features or parts or elements or steps recited but may include other elements, features, parts or steps not expressly listed or inherent to such process, method, article, or apparatus. Furthermore, the terms “a” and “an” used herein are intended to be understood as meaning one or more unless explicitly stated otherwise. Moreover, the terms “first”, “second”, etc. are used merely as labels, and are not intended to impose numerical requirements on or to establish a certain ranking of importance of their objects.

[0083] List of reference numerals10 Orthopaedic implant 150 Implant holder point100 Frame 155 Opening105 Central cavity 160 Panels110 Openings 165 Pores110a First opening 200 Trial implant110b Second opening 202 Body110c Third opening 205 Radio-opaqueHOd Fourth opening orientation markers111 Upper hemisphere of frame 210 Outer surface of body112 Lower hemisphere of frame 215 Lumen113 First side of frame 220 Central cavity114 Second side of frame 225 Openings115 Arm portions 230 Radio-opaque horizon markers120 Upper portion of frame 300 Adaptor sleeve125 Lower portion of frame 305 Collar or flange130 Lumen 310 Body135 Central axis 315 Inner bore140 Cylindrical wall 320 Central longitudinal axis

Claims

CLAIMS1. An orthopaedic implant including: a frame for interfacing with bone or bone tissue, the frame including: a central cavity adapted to contain osteogenic material; and at least one opening providing a dedicated delivery point for insertion of osteogenic material into the central cavity; and a plurality of panels supported by the frame and adapted to be in direct contact with the bone or bone tissue, wherein each panel has a porous surface geometry, and wherein each panel has a curved arrangement to provide the implant with a substantially spherical shape, with the plurality of panels being arranged to surround the central cavity to provide a closed system.

2. The orthopaedic implant according to claim 1, wherein the panels are integrally formed with the frame as a unified system.

3. The orthopaedic implant according to claim 1 or 2, wherein the panels extend from the frame so as to be flush with the surface of the frame, thereby providing a continuous spherical enclosure of the central cavity.

4. The orthopaedic implant according to any one of the preceding claims, wherein the at least one opening is provided as two openings located on a hemisphere of the frame.

5. The orthopaedic implant according to claim 4, wherein a first of the two openings is located on an opposite side of the frame to a second of the two openings.

6. The orthopaedic implant according to any one of the preceding claims, wherein the frame includes a plurality of elongated and interconnected arm portions defining the central cavity.

7. The orthopaedic implant according to claim 6, wherein some of the arm portions are arranged to extend in a first direction between an upper portion and a lower portion of the frame.

8. The orthopaedic implant according to claim 7, wherein some of the arm portions are arranged to extend in a second direction, with the second direction being transverse to the first direction.

9. The orthopaedic implant according to any one of claims 6 to 8, wherein each arm portion of the frame has a curved arrangement to provide the frame with a substantially spherical shape, and wherein the at least one opening extends through a least one of the arm portions to be in communication with the central cavity.

10. The orthopaedic implant according to any one of the preceding claims, wherein the porous surface geometry of each panel includes a plurality or network of non-uniform pores, wherein the pores extend through the panel to be in communication with the central cavity.

11. The orthopaedic implant according to claim 10, wherein the plurality or network of non- uniform pores forms a lattice structure.

12. The orthopaedic implant according to claim 10 or 11, wherein the non-uniform pores are configured in a randomised or biomimetic manner.

13. The orthopaedic implant according to any one of the preceding claims, wherein one or more of the panels has a graded or hierarchical porosity of between approximately 60 and 80%.

14. The orthopaedic implant according to claim 13, wherein the porosity is approximately between approximately 60 and 70%.

15. The orthopaedic implant according to claim 13 or 14, wherein the porosity is approximately 63%.

16. The orthopaedic implant according to any one of the preceding claims, wherein the porous surface geometry is macroporous, in which the panel has pore sizes ranging from between approximately 300 to 3,000 microns.

17. The orthopaedic implant according to claim 16, wherein the pore sizes are approximately 1,400 microns on average.

18. The orthopaedic implant according to any one of the preceding claims, wherein the porous surface geometry is microporous, in which the panel has pore sizes ranging from between approximately 15 to 60 microns.

19. The orthopaedic implant according to any one of the preceding claims, wherein the porous surface geometry is nanoporous.

20. The orthopaedic implant according to any one of the preceding claims, wherein the at least one opening is located at an interface between two of the panels.

22. The orthopaedic implant according to any one of the preceding claims, wherein the frame further includes one or more implant holder points, wherein each implant holder point includes at least one opening providing access to the central cavity.

23. The orthopaedic implant according to any one of the preceding claims, wherein the implant is formed from a material having a modulus of elasticity approximating that of native bone.

23. The orthopaedic implant according to any one of the preceding claims, wherein the implant has a diameter of between approximately 32 and 40 mm, and the central cavity is configured to accommodate a volume of osteogenic material ranging from between approximately 5 and 10 cubic centimetres.

24. The orthopaedic implant according to any one of the preceding claims, further including a lumen extending through the central cavity of the frame and along a central axis thereof, wherein the lumen is adapted to provide access for insertion of an intramedullary nail therethrough.

25. The orthopaedic implant according to claim 24, wherein the lumen has a diameter sized to receive a standard intramedullary nail.

26. An adaptor sleeve for the orthopaedic implant according to claim 25, the adaptor sleeve configured to be received in the lumen and including a collar and a body extending from the collar, the body including an inner bore sized to receive an intramedullary nail having a smallerdiameter than the standard intramedullary nail, and the collar being adapted to engage an lower portion of the frame.

27. A trial implant configured to match the orthopaedic implant according to any one of the preceding claims.

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