Bendable titanium alloy implant

Abstract

An implantable device (2) includes a portion configured such that at least a majority of the portion, as measured by volume, comprises Ti64 (Ti-6AI-4V) alloy, and further, the portion is capable of bending about a bending axis to a bend angle of at least about 50 degrees while maintaining structural integrity.

Description

[Technical field]

[0001] The present invention relates to titanium alloy implants, and more particularly to a process for producing such implants by rapid manufacturing and providing such implants with increased malleability. [Background technology]

[0002] The field of rapid prototyping and additive manufacturing has seen many advancements over the years, particularly for rapid prototyping of articles such as prototype parts and mold dies. These advancements have reduced manufacturing costs and time while improving the accuracy of the final product compared to traditional machining processes, such as those in which a material (e.g., metal) begins as a block of material and is then machined into the final product.

[0003] However, the main focus of rapid prototyping of three-dimensional structures such as surgical implants has been to increase the density of the rapid prototyping-produced structures. Examples of modern rapid prototyping / additive manufacturing techniques include sheet lamination, adhesive bonding, laser sintering (or selective laser sintering), laser melting (or selective laser melting), photopolymerization, droplet deposition, stereolithography, 3D printing, fused deposition modeling, and 3D plotting. In particular, in the field of selective laser sintering, selective laser melting, and 3D printing, improvements in the production of high-density parts have made those techniques useful for designing and precisely manufacturing articles such as high-density metal parts. However, these techniques often require post-forming and / or finishing processes to provide the prototyped parts with the necessary mechanical properties (e.g., hardness, strength, malleability, toughness) required to meet the demands required for various types of surgical implants. Summary of the Invention [Means for solving the problem]

[0004] According to one embodiment of the present disclosure, an implantable device includes a portion configured such that at least a majority of the portion, as measured by volume, comprises Ti64 (Ti-6Al-4V) alloy, and further, the portion is capable of bending to a bend angle of at least about 50 degrees about a bending axis while maintaining structural integrity.

[0005] According to another embodiment of the present disclosure, an acetabular cage has a dome for insertion into the acetabulum and a flange integral with the dome for attachment to a portion of the ilium. The dome and flange are constructed from a Ti64 alloy. At least a portion of the flange is capable of bending about a bending axis to a bending angle of at least about 90 degrees while maintaining structural integrity.

[0006] According to an additional embodiment of the present disclosure, a method of preparing an implant for implantation includes bending a portion of the implant about a bend axis to a bend angle of at least about 50 degrees, where at least a majority of the portion, as measured by volume, comprises Ti64 alloy, where the portion maintains structural integrity during and after the bending step. [Brief description of the drawings]

[0007] The foregoing summary and the following detailed description of exemplary embodiments of the present application will be better understood when read in conjunction with the accompanying drawings. For the purpose of illustrating the features of the present application, illustrative embodiments are shown in the drawings. It should be understood, however, that the present application is not limited to the precise arrangements and instrumentalities shown. In the drawings: [Figure 1A] FIG. 1 is a perspective view of a surgical implant attached to a patient's anatomy according to one embodiment of the present disclosure. [Figure 1B] FIG. 2 is a perspective view of an implant attached to a complementary second implant and to a patient's anatomy according to one embodiment of the present disclosure. [Figure 1C] FIG. 1B is a perspective view of the implant shown in FIG. 1A. [Figure 1D]FIG. 1B is another perspective view of the implant shown in FIG. 1A. [Figure 1E] 1B is a perspective view of an additional embodiment of a surgical implant similar to the implant shown in FIG. 1A, each according to an embodiment of the present disclosure. [Figure 1F] 1B is a perspective view of an additional embodiment of a surgical implant similar to the implant shown in FIG. 1A, each according to an embodiment of the present disclosure. [Figure 2A] FIG. 1B is a perspective view of a partially fabricated version of the implant shown in FIG. 1A shown in an example build orientation relative to the additive manufacturing powder bed. [Figure 2B] FIG. 1B is a perspective view of a partially fabricated version of the implant shown in FIG. 1A shown in an alternative build orientation relative to the powder bed. [Figure 3A] 3A and 3B show close-up views of exemplary grain structures of Ti64 alloys having increased malleability for use in implant construction. The grain structures shown in FIGS. 3A and 3B were produced in the same Ti64 material using slightly different custom heat treatment processes that allow for tailoring the size of the alpha phase lamellae; for example, the average width of the alpha phase lamellae in FIG. 3B is larger than that in FIG. 3A . [Figure 3B] 3A and 3B show close-up views of exemplary grain structures of Ti64 alloys having increased malleability for use in implant construction. The grain structures shown in FIGS. 3A and 3B were produced in the same Ti64 material using slightly different custom heat treatment processes that allow for tailoring the size of the alpha phase lamellae; for example, the average width of the alpha phase lamellae in FIG. 3B is larger than that in FIG. 3A . [Figure 3C] FIG. 3C illustrates an additional close-up view of the grain structure of Ti64 alloy produced using the same custom heat treatment process used to produce the grain structure shown in FIG. 3B. [Figure 3D] FIG. 3C illustrates an additional close-up view of the grain structure of Ti64 alloy produced using the same custom heat treatment process used to produce the grain structure shown in FIG. 3B. [Figure 3E] FIG. 1 shows a close-up view of the grain structure of a prior art sample of ISO 20160 alpha + beta titanium alloy. [Figure 4A] 4 is a chart showing tensile test results of a structural test member having a grain structure substantially similar to the grain structure shown in FIGS. 3A-3B. [Figure 4B] 4 is a chart showing tensile test results of a structural test member having a grain structure substantially similar to the grain structure shown in FIGS. 3A-3B. [Figure 5A] 4 is a chart comparing bend test data of structural test members having a grain structure substantially similar to that shown in FIGS. 3A-3B with structural test members lacking such grain structure. [Figure 5B] FIG. 5B is a photograph of the resulting bent structural test member after bend testing used to obtain the results shown in FIG. 5A, having a grain structure substantially similar to that shown in FIGS. 3A-3B. [Figure 5C] 5B is a photograph of the resulting bent structural test member after bend testing used to obtain the results shown in FIG. 5A, lacking the grain structure shown in FIGS. 3A-3B. [Figure 5D] 4 is a chart comparing additional bend test data of structural test members having a grain structure substantially similar to that shown in FIGS. 3A-3B with structural test members lacking the aforementioned grain structure; [Figure 6] 4 is a chart showing additional bend test data for structural test members having various thicknesses and grain structures substantially similar to those shown in FIGS. 3A-3B. [Figure 7] FIG. 1 is an exploded perspective view of a surgical system having a bendable implant and a bendable hardenable trial member in accordance with an embodiment of the present disclosure; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present disclosure may be more readily understood by reference to the following detailed description in conjunction with the accompanying drawings and examples, which form a part of this disclosure. It is to be understood that the present disclosure is not limited to the specific apparatus, methods, applications, conditions or parameters described and / or shown herein, and the terminology used herein is for the purpose of describing specific embodiments by way of example only, and is not intended to limit the scope of the present disclosure. Also, as used in the specification, including the appended claims, the singular forms "a", "an", and "the" include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise.

[0009] The term "titanium-based," as used herein with respect to an object such as an implant, means composed predominantly of titanium (Ti) or a titanium alloy.

[0010] The term "plurality," as used herein, means more than one. When a range of values ​​is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed in an approximation form, by use of "about," it will be understood that the particular value forms another embodiment. All ranges are inclusive and combinable.

[0011] As used herein with respect to dimensions, angles, ratios, and other geometric features, the terms "approximately," "about," and "substantially" take into account manufacturing tolerances. Additionally, the terms "approximately," "about," and "substantially" may include 10% greater or less than the stated dimension, ratio, or angle. Additionally, the terms "approximately," "about," and "substantially" may equally apply to the specific values ​​stated.

[0012] Terms such as first, second, etc. may be used herein to describe various elements, but it should be understood that these elements should not be limited by these terms. These terms are used to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the embodiments disclosed herein.

[0013] The embodiments disclosed herein relate to surgical implants made of titanium alloys having superior strength and increased malleability that allows the implant to bend intraoperatively, such as to shape to correspond to an associated patient anatomy. The surgical implants disclosed herein are also suitable for rapid manufacturing by additive manufacturing processes followed by heat treatment processes that are configured to provide a manufactured implant with increased malleability. Titanium (Ti) and various titanium alloys, particularly Ti64 (titanium-aluminum-vanadium alloy, also designated Ti-6Al-4V), have mechanical properties that make them desirable for surgical implants, such as strength, lighter weight (low density) compared to other implant materials (e.g., stainless steels), durability, resistance to repeated loading, ability to withstand strain (e.g., during internal fixation to a patient's anatomy), corrosion resistance, biocompatibility, and ability to bond with bone. Although titanium alloy implants have many of these excellent properties, they tend to be difficult to bend, especially during the intraoperative shaping process to conform the shape of the implant to the patient's anatomy. However, the titanium alloy implants disclosed herein have a grain structure that provides the implant with increased malleability that allows for intraoperative bending, such as to shape the implant to the relevant patient anatomy. Non-limiting examples of types of surgical implants that would benefit from the malleable titanium alloys disclosed herein include acetabular cages, craniomaxillofacial (CMF) plates, and trauma bone plates. The illustrated embodiments of the implant manufacturing, processing, and finishing processes, and methods of implant use below refer to acetabular cages, but it should be understood that the processes, methods, and structures disclosed herein can be used for the construction and use of numerous other types of implants.

[0014] 1A-1C, an exemplary implant 2 for hip joint repair is shown. The illustrated implant 2 is referred to herein as an "acetabular cage" 2 and is configured for attachment to an acetabulum 5 for repair of various acetabular defects in a pelvis 3. The cage 2 includes a socket portion or "dome" 4 shaped for insertion and attachment within the acetabulum 5. The cage 2 includes a first flange 6 extending from the dome 4 and configured for attachment to an ilium 7 of the pelvis 3. The first flange 6 is also referred to herein as the "iliac flange" 6. The iliac flange 6 also defines a bend 8, specifically an S-shaped bend ("S bend") 8, at a portion thereof proximate the dome 4. The S bend 8 is configured to accommodate and generally conform to the geometry of the acetabular rim 11 and the body of the ilium 13. The iliac flange 6 may also define a neck 15 adjacent the dome 4. The neck 15 is configured to facilitate engagement of the iliac flange 6 with the acetabular rim 11 and also to facilitate bending and / or twisting of the iliac flange 6 to conform to the patient's anatomy. The cage 2 may also include an optional second flange 10 extending from the dome 4 at a location generally opposite the iliac flange 6 and configured for attachment to an ischium 9 of the pelvis 3. The second flange 10 is also referred to herein as the "sitz bone flange" 10. In other embodiments, as shown in FIG. 1E, the cage 2 may be formed to have the iliac flange 6 but lack an ischium flange.

[0015] It should be appreciated that the dome 4 may be configured to seat within the acetabulum 5 and contact the acetabular surface (e.g., the articular (lunate) surface, the acetabular fossa, and / or a reamed or otherwise surgically modified portion thereof), as shown in FIG. 1A, and may also be configured to seat within an acetabular cup 12 in direct contact with the acetabular surface, as shown in FIG. 1B. The cage 2 is malleable enough to allow the surgeon to manipulate, bend, and shape portions thereof to conform to the shape of the adjacent patient anatomy. In particular, the iliac flange 6 and optional ischium flange 10 may be bent and shaped to have contours that match the associated contours of the ilium 7 and ischium 9, respectively. One or more portions of the cage 2 may have geometric features that further facilitate bending. For example, the neck 15 of the iliac flange 6 is configured to facilitate bending, twisting, and shaping of the iliac flange 6.

[0016] 1C-1D, the cage 2 has a first or inner surface 14 configured to face the pelvis when implanted, and an opposing second or outer surface 16 configured to face away from the pelvis 3 when implanted. The cage 2 defines a thickness T measured along a direction perpendicular to corresponding portions of the inner surface 14 and the outer surface 16. The cage thickness T is preferably in the range of about 0.5 mm to about 3.0 mm, more particularly in the range of about 0.9 mm to about 2.2 mm, and even more particularly in the range of about 0.9 mm to about 1.5 mm. It should be understood that one or more portions of the cage 2 can have a reduced thickness relative to various other portions of the cage 2. In such embodiments, the portion having the reduced thickness can be configured to facilitate bending and shaping along such portion.

[0017] The cage 2 has a first or upper end 18 located at the end of the iliac flange 6 and a second or lower end 20 located at the end of the ischial flange 10 in embodiments having the ischial flange 10. In embodiments lacking an ischial flange, the lower end 20 of the cage 2 may be at the lowermost edge of the dome 4. The cage 2 has an anterior side 22 and an opposing posterior side 24. It should be understood that anatomical directional terms such as "medial," "lateral," "superior," "inferior," "anterior," and "posterior," when used herein with respect to an implant such as the acetabular cage 2, generally refer to the relative position of the implant as it is configured to face when implanted.

[0018] The cage 2 includes fixation features for attachment to bone. As shown in Figures 1D-1E, the dome 4, iliac flange 6, and optional ischial flange 10 can each include one or more respective fixation holes 26a,b for receiving a respective fixation member, such as a bone screw, for attaching the associated portion of the cage 2 to the underlying bone. For example, the iliac flange 6 and / or optional ischial flange 10 can include one or more flange holes 26a for attaching the respective flange 6, 10 to the underlying bone. One or more of the flange holes 26a can have internal threads for engaging with complementary threads on the exterior of the head of a set screw.

[0019] As shown in FIG. 1F, one or more of the flange holes 26a may extend through the respective flanges 6, 10 along a central hole axis 27 oriented at an angle A1 offset from a transverse axis 29 that extends orthogonally through the inner and outer surfaces 14, 16 of the cage 2 adjacent the hole 26a. Such holes 26a may be referred to as "tilted holes." It should be appreciated that one or more of the flange holes 26a, including the tilted and non-tilted holes 26a, may have threads or other locking structure for engaging in a locking manner with complementary threads on the head of a variable angle (VA) set screw, thereby providing VA fixation. It should be appreciated that the inclusion of at least one tilted flange hole 26a may provide significant advantages to the cage 2. One such advantage is that the angle A1 of the hole 26a may be adjusted to provide a target insertion trajectory for an associated bone screw. In this manner, the angle A1 may be adapted to adjust the insertion trajectory to a particular geometry of a target portion of a bone, thereby providing enhanced fixation with the target portion of a bone. For example, the angle A1 of the holes 26a on the iliac flange 6 can be tailored to provide an insertion trajectory that is tailored for the particular geometry of the target portion of the ilium, such as an insertion trajectory that is substantially parallel to the bone in the target iliac portion. In this manner, the angle A1 can be tailored to increase the efficiency with which the bone screw bites into or otherwise engages the target bone. Another advantage of the angled holes 26a is that the angle A1 can be tailored to reduce the amount of soft tissue disruption (e.g., dissection, resection, and / or retraction) adjacent the holes 26a. For example, the angle A1 of the holes 26a in the iliac flange 6 can be tailored to reduce the amount of gluteal muscle resection required to attach the iliac flange 6 to the associated portion of the ilium.

[0020] It should be appreciated that such VA locking holes 26a in the iliac and / or ischial flanges 6, 10 can be configured as more fully described in U.S. Pat. No. 10,772,665, published Sep. 15, 2020 in the name of Bosshard et al. ("Reference '665") and U.S. Pat. No. 11,013,541, published May 25, 2021 in the name of Bosshard et al. ("Reference '541"), the entire disclosures of each of which are incorporated herein by reference. Additionally or alternatively, one or more of the holes 26a in the iliac and / or ischial flanges 6, 10 can be VA locking holes 26a having a polygonal hole shape (when viewed in a reference plane perpendicular to the central axis of the respective hole), such as, for example, a triangular hole shape. For example, the iliac flange 6 and / or optional ischial flange 10 can include one or more triangular VA locking flange holes 26a, which can be configured as more fully described in U.S. Pat. No. 11,179,180, published November 23, 2021 in the name of Oberli et al. ("Reference '180"), and U.S. Patent Application Publication No. 2021 / 0015526(A1), published January 21, 2021 in the name of Oberli et al. ("Reference '526"), the entire disclosures of each of which are incorporated herein by reference. For embodiments of the cage 2 configured for use with an acetabular cup 12, the dome 4 can have one or more fixation holes 26b, which are preferably configured to align with one or more corresponding fixation holes in the acetabular cup 12.

[0021] Selected portions of the cage 2 can have gripping features to provide a stronger contact interface with the underlying bone. For example, one or more selected portions of the inner surface 18 can have ridges to press into the underlying bone in such a manner as to enhance fixation. Additionally or alternatively, the material of the cage 2 along one or more selected portions of the inner surface 18 can be porous, i.e., have a porous three-dimensional (3D) structure defining a multiplicity of holes, which can be tailored according to various design objectives, such as, by way of non-limiting example, to promote bone ingrowth into the holes to enhance post-operative fixation with the underlying bone. Features of the porous structure, including variations of such features, are described in more detail below.

[0022] The implants of the present disclosure, such as the cage 2 of the embodiment illustrated herein, are constructed from a titanium alloy, specifically a titanium-aluminum-vanadium alloy: Ti-6Al-4V ("Ti64"). This particular titanium alloy (Ti64) is advantageous for constructing implants because Ti64 is stronger and more resistant to fatigue than titanium (including grades of "commercially pure" titanium (Ti-CP)) and other titanium alloys. However, prior art implants, such as acetabular cages, constructed from Ti64 are difficult to bend intraoperatively, particularly by a surgeon, without forming cracks, particularly in the bending region. The heat treatment process described below demonstrates the ability to increase the malleability of implants constructed from Ti64, such that these cages 2 can be bent intraoperatively, for example, by a surgeon, without losing structural integrity. In this manner, the inventors have discovered a technique that allows the strength and durability of Ti64 to be employed in a surgical implant (e.g., acetabular cage 2) that is also bendable, which represents a significant advancement in the art of surgical implants.

[0023] The use of Ti64 as the implant material also allows the cage 2 to be rapidly manufactured by an additive manufacturing process, such as a laser-activated powder bed fusion (PBF) process, which forms the cage 2 into the desired pre-operative shape. Features of the implant manufacturing and finishing process are described below.

[0024] The geometry of the cage 2 can be created in a three-dimensional (3D) virtual space, thereby providing a 3D virtual model of the cage 2. After the 3D virtual model of the cage 2 is created, a rapid additive manufacturing process can be used to create a physical version of the cage 2 with the geometry and features of the 3D virtual model. The 3D virtual model of the cage 2 can optionally be designed with the aid of patient scan data of the particular anatomical structure to which the cage 2 is to be attached. Such patient scan data can include, as a non-limiting example, a series of CT scan cross-sections of the acetabulum and adjacent portions of the ilium 7 and ischium 9. In particular, the iliac flange 6 and optional ischium flange 10 can be tailored in the 3D virtual space to have contours that correspond to the contours of the portions of the ilium 7 and ischium 9 to which the flanges 6, 10 are attached, respectively. After the 3D virtual model of the cage 2 is created, a rapid additive manufacturing process can be used to create the cage 2 with the tailored patient-specific 3D virtual geometry.

[0025] The cage 2 can be constructed using a laser-activated PBF process, which may also be referred to as a laser melting process, including selective laser sintering (SLS) and selective laser melting (SLM) processes. A non-limiting example of a laser melting process for constructing the cage 2 is described below. First, a thin layer of powder is distributed on a worktable (often referred to as a "build platform") such that at least one powder layer forms a powder bed. The powder includes constituent particles of Ti64 material, which may be particles of various sizes, size distributions, and geometric shapes, and the properties of the powder can be selected based on parameters that result in a preferred fusion and fused grain structure of the constructed cage 2. As used herein, the terms "build," "built," and their derivatives refer to a build formed by fusing together particles in a powder bed by a PBF process. Selected areas of the top surface of the powder layer (the "build surface") are melted by exposure to a directed energy source, typically a laser beam. Thus, the exposure pattern of the laser beam forms a cross section of a three-dimensional object. The cage 2 is built up by successive fusion of the so-formed cross-sections stacked layer by layer along the vertical direction. Between the fusion of each layer, the build platform is incremented downwards and a new layer of powder is deposited on the build surface. These steps (e.g., lowering the worktable, dispensing a new layer of powder on the powder bed, and exposing the new layer of powder to the laser source 1) are repeated layer by layer as necessary, resulting in the creation of the cage 2 as a plurality of successively fused cross-section layers. It is to be understood that the laser fusion process can also be characterized as a 3D printing process. Thus, the term "built" can be used synonymously with the term "printed" herein.

[0026] During the PBF process, the cage 2 can be built in various orientations in the power bed. Two non-limiting examples of such build orientations are shown in Figures 2A-2B. As shown in Figure 2A, the cage 2 can be built with the outer surface 16 facing down (and the inner surface 14 facing up) the powder bed. Alternatively, as shown in Figure 2B, the cage 2 can be built with the front side 22 facing down (and the rear side 24 facing up) in the powder bed. In either of these build orientations (as well as other build orientations), the cage 2 can be built down on a base member 30 of stock material, which can be used as a support structure during post-build processes and then removed. As shown, the cage 2 can be built in the powder bed without fastener holes, which can then be formed in the cage 2 during a machining process, such as with a multi-axis computer numerically controlled (CNC) machine. In other embodiments, the cage 2 can be constructed with fixation holes that can be further machined and finished in a subsequent machining process. During the PBF process, the dome 4 can optionally be constructed without a support structure (i.e., stock material) underneath the dome 4 as shown. In other embodiments, the dome 4 can be constructed with a support structure underneath it that is subsequently removed.

[0027] Preferably, the majority of the cage 2 can be constructed to have a solid structure (e.g., have a packing density of 100 percent). In such embodiments, one or more portions of the cage 2 can have a packing density of less than 100 percent, such as a packing density ranging from about 50 percent to about 99.9 percent, and thus can have a lower density than the solid portions. The packing density of less than 100 percent in such one or more portions can be caused by such portions being porous. For example, such one or more portions of the inner surface 14 of the cage 2 can be porous as described above to promote bone growth into such surface portions of the cage 2. Such porous portions of the cage 2 can be produced by rapid manufacturing according to techniques and features more fully described in U.S. Patent Application No. 17 / 732,750, filed on April 29, 2022 in the name of Kavanagh et al., the entire disclosure of which is incorporated herein by reference.

[0028] After the cage 2 is constructed, it is subjected to one or more treatment processes, such as, for example, one or more heat treatment processes, to modify the grain structure of the as-printed Ti64 implant material in a manner that increases the malleability of the cage 2, and in particular to allow a surgeon to intraoperatively bend a portion of the cage 2 without cracking, breaking, or otherwise mechanically failing such portion. In particular, to provide the increased malleability disclosed herein, the Ti64 grain structure is modified from an as-printed metastable martensitic structure to a lamellar alpha + beta phase with tunable lamella size. Referring now to Figures 3A-3D, the resulting grain structures of Ti64 samples printed and processed according to embodiments herein are shown. For example, Figures 3A and 3B show close-up views of exemplary grain structures of respective printed Ti64 alloy samples made by using Ti64 powder with the same properties and subjecting the printed samples to slightly different custom heat treatment processes. It can be seen that the average width of the alpha phase lamellae α in Figure 3B is larger than that in Figure 3A, suggesting that it is possible to tailor the size of the alpha phase lamellae α, particularly by increasing their size, which has been observed to increase malleability. Referring now to Figures 3C and 3D, additional close-ups show the grain structure produced using the same custom heat treatment process used to produce the grain structure shown in Figure 3B. It can be seen that the alpha phase lamellae α have an increased width Wα that is larger than the prior art Ti64 grain structure.

[0029] The treatment process herein allows for the production of alpha phase lamellae α with increased size, such as increased width Wα (FIG. 3D), which results in a more malleable material, albeit at the expense of material strength. Cylindrical specimens of printed and processed Ti64 made according to embodiments herein have been observed to undergo elongation in the range of 15%-23% during testing, which is a significant improvement over prior art Ti64. For comparison, FIG. 3E shows the grain structure (including lamellae) of a specimen of ISO 20160 alpha + beta titanium alloy. The image shown in FIG. 3E is a micrograph A11 from ISO 20160-2006 taken at 200x magnification.

[0030] The constructed and processed cage 2 may be subjected to further processes, such as one or more machining, polishing, roughening, and / or coating processes, as needed. For example, one or more additional holes may be formed in the cage 2, such as by drilling, milling, punching, cutting, and the like, as non-limiting examples. It should be understood that holes may be formed in the cage 2 for the purpose of increasing the flexure of the cage in a portion adjacent the hole. Additionally, the constructed and processed cage 2 may be subjected to additional machining processes, such as wire electrical discharge machining (wire EDM), to profile cut the cage 2, such as to remove support structures.

[0031] The constructed and processed cage 2 demonstrates material properties with superior malleability over prior art Ti64 components of similar thickness. Referring now to Figures 4A-4B, two sets of tensile test results are shown for printed and finished Ti64 tensile test bars made with tailored heat treatments. In Figure 4A, six specimens of printed and processed Ti64 cylinders were subjected to room temperature tensile testing to measure four qualities: (1) ultimate tensile strength (measured in megapascals (MPa)), (2) yield strength at 0.2% offset (also called 0.2% proof test) (measured in MPa), (3) elongation after break (%), and (4) area reduction (%). For comparison purposes, the minimum tensile requirements for these four qualities according to ASTM F3001-14 Class A are also listed. In FIG. 4B, three specimens of the printed and processed Ti64 cylinders were subjected to similar tensile testing to measure, among other qualities, the same four qualities measured in FIG. 4A: (1) ultimate tensile strength ("UTS") (measured in MPa), (2) yield strength at 0.2% offset ("0.2% proof test") (measured in MPa), (3) elongation after break ("elongation A%), and (4) percent area reduction ("area reduction Z%). It should be understood that the samples depicted in FIG. 4B were subjected to slightly different heat treatment parameters than the samples depicted in FIG. 4A. The results shown in FIGS. 4A-4B demonstrate that the printed and processed Ti64 samples measured significantly higher elongations, specifically elongations of about 15% to about 23%, at the slight expense of yield strength and ultimate tensile strength. Note that elongation of 15-23% represents a significant advantage over prior art 3D printed Ti64 constructs.

[0032] 5A-5C, there are shown results of three-point bend tests performed on five different specimens of plate test coupons: (1) "Ti CP2 Anneal 1.34mm" (annealed commercially pure (CP) grade 2 titanium having a thickness of 1.34mm), (2) "Ti CP2 Stress Relief 1.34mm" (stress relieved commercially pure (CP) grade 2 titanium having a thickness of 1.34mm), (3) "Ti CP2 Anneal 1.57mm" (annealed commercially pure (CP) grade 2 titanium having a thickness of 1.57mm), (4) "Ti64 CHT 1.34mm" (heat treated (custom heat treated (CHT)) Ti64 alloy having a thickness of 1.34mm), and (5) "Ti64 HIP 1.34mm" (heat treated by hot isostatic pressing (HIP) Ti64 alloy having a thickness of 1.34mm). Test coupons for samples (1)-(5) were rapidly manufactured using a laser melting PBF process at approximately 50 mm length and 20 mm width. Each sample was subjected to a bend displacement target of 8 mm, corresponding to a bend angle of more than 90 degrees, using a test setup consistent with the requirements of ASTM E290, and displacement versus applied force was plotted. Additionally, bend tests were performed by bending the test coupons around a 5 mm diameter mandrel.

[0033] As shown in FIG. 5A, specimen (4) (Ti64 CHT 1.34 mm) can be bent to the full test displacement (equivalent to a minimum bending angle of 90 degrees) at a maximum applied force of about 3.25 kN, which is sufficient for a cage 2 (particularly its flanges) with the same thickness to be bent intraoperatively by a surgeon, such as to match the shape of the cage 2 to the relevant patient anatomy. These results compare favorably to commercially pure titanium specimens, especially considering the increased strength of Ti64 over commercially pure titanium. As shown in FIG. 5B, three test subjects of the specimen (4) coupons exhibited clean bending and maintained structural integrity (meaning that the specimens did not show any signs of mechanical failure, such as cracks, delamination, or other failure modes). As also demonstrated by these tests, the hot isostatically pressed (HIP) Ti64 specimens experienced crack failure at a displacement of about 3.75 mm (applied force of about 2.75 kN), as shown in FIG. 5A, and the cracks can be seen in FIG. 5C. These results demonstrate that implants constructed from Ti64 and custom heat treated have superior bending properties to those constructed from HIP Ti64.

[0034] Referring now to FIG. 5D, further bending tests indicate that the cage thickness is a significant factor in bendability. The results shown in FIG. 5D are for three different test coupons: (6) “Ti64 CHT 1.34mm” (a heat treated Ti64 alloy having a thickness of 1.34mm (same specimen parameters as specimen (4) shown in FIG. 5A), (7) “Ti64 CHT 1.64mm” (a heat treated Ti64 alloy having a thickness of 1.64mm), and (8) “Ti CP2 Annealed The results are based on similar three-point bending tests described above with reference to FIGS. 5A-5C performed on Ti64 heat treated specimens (annealed commercially pure (CP) grade 2 titanium having a thickness of 1.89 mm). These results demonstrate that increasing the thickness of the Ti64 heat treated specimens from 1.34 mm to 1.64 mm (an increase of 0.3 mm) can cause failure at approximately 5 mm of displacement (and 4.0 kN of bending force). These results indicate that for acetabular cages 2 constructed of this material (heat treated Ti64), the portions of the cage 2 adapted for flexion (e.g., the iliac flange 6 and / or optional ischial flange 10) should be formed with a thickness less than 1.64 mm, and preferably closer to 1.5 mm.

[0035] Referring now to FIG. 6, further bending tests show that implant thicknesses up to about 1.5 mm can be bent to a target test displacement of about 8 mm (equivalent to a bend angle of greater than 90 degrees, using a test setup consistent with the requirements of ASTM E290) without fracture. In these bending tests, four sample groups of test coupons having thicknesses of 0.9 mm, 1.1 mm, 1.3 mm, and 1.5 mm, respectively, were subjected to a three-point bending test similar to that described above with reference to FIGS. 5A-5D. Each sample group shown in FIG. 6 included eight test coupons of the respective thickness. As shown in the figure, each of these sample groups was able to achieve the target test displacement (8 mm, 90+ degrees) without fracture.

[0036] As mentioned above, the bendable Ti64 acetabular cage 2 disclosed herein provides the strength and other related advantages of Ti64 while also allowing the surgeon to bend portions of the cage 2 intraoperatively as needed to conform to the patient's anatomy. During a hip joint repair surgery, such as surgery to treat an acetabular defect, such as a Type 2A, Type 2B, Type 2C, Type 3A, or Type 3B acetabular defect, the surgeon can expose and prepare the acetabulum to receive an acetabular cup 12, such as by removing soft tissue from the acetabulum and surrounding area and optionally reaming the acetabulum. With the acetabulum prepared, the surgeon can insert the cup cavity cup 12 into the acetabulum in a desired orientation. The surgeon may then move the acetabular cage 2 into position adjacent the cup 12, specifically by bringing the dome 4 of the cage 2 into contact with or at least close to the concave exposed surface of the cup 12 such that at least one of the holes 26b in the dome 4 is aligned with at least one corresponding hole in the cup 12. With the cage 2 in such position, the surgeon may bend and shape the iliac flange 6 to have a contour approximately equal to the contour of the portion of the ilium that it will contact.

[0037] It should be appreciated that the surgeon does not need to maintain the cage 2 in contact or proximity to the cup 2 while bending the iliac flange 6 into the desired shape. The surgeon may choose to move the cage 2 into a position to visually reference the iliac flange 6 against the corresponding portion of the ilium, and then move the cage 2 to a more comfortable position to perform the bend. This bending and shaping process may also be iterative, whereby the surgeon may bring the cage 12 into contact and / or proximity with the cup 12 to visually reference the iliac flange 6 against the corresponding portion of the ilium, then move the cage 2 into a more comfortable position to perform the bend, return the cage 2 to contact or proximity with the cup to further visually reference the iliac flange 6 against the corresponding portion of the ilium, and repeat these steps until a satisfactory contour and shape is imparted to the iliac flange 6.

[0038] Additionally, if the selected cage 2 includes an ischial flange 10, the surgeon can bend and shape the ischial flange 10 to have a contour approximately equal to the contour of the portion of the ischial bone that the ischial flange 10 contacts. It is understood that the surgeon can use similar steps to shape the ischial flange 10 as described above to shape the iliac flange 6. To attach the cage 2 and cup 12 to the acetabulum, the surgeon can insert a locking member, such as a bone screw, through one or more of the aligned holes in the dome 4 and cup 12. The surgeon can also insert one or more additional locking members, such as a bone screw, through one or more holes 26a in the iliac flange 6 and into the underlying bone to attach the iliac flange to the corresponding portion of the ischial bone. If the selected cage 2 includes an ischial flange 10, the surgeon can also insert one or more additional locking members, such as a bone screw, through one or more holes 26a in the ischial flange 10 and into the underlying bone to attach the ischial flange 10 to the corresponding portion of the ischial bone. Additionally or alternatively, if the selected cage 2 includes an ischial flange 10, the surgeon may insert a portion, and up to the entirety, of the ischial flange 10 into the ischial bone, such as by drilling or otherwise forming a slot or opening in the ischial bone and inserting the ischial flange 10 therein. It should be appreciated that the surgeon may choose to attach a particular portion of the cage 2 to an underlying bone, such as the dome 4, and mold a separate portion of the cage 2, such as the iliac flange 6 and / or the ischial flange 10, to the corresponding bone.

[0039] 7, a trial system 100 for shaping the acetabular cage 2 can include a trial member 52 configured to be manipulated, bent, or otherwise shaped in a substantially conformal manner with associated anatomical structures to assist the surgeon in bending the cage 2 into a similar shape. The trial member 52 is preferably configured to transition from a neutral state to a first state in which the trial member 52 can be easily bent to match the contours of the underlying anatomical structures. The trial member 52 is also preferably configured to transition from the first state to a second state in which the trial member 52 substantially maintains its bent / contoured shape. In this manner, the surgeon can use the trial member 52 intraoperatively to assist in patient-specific bending and shaping of the acetabular cage 2. For example, the trial member 52 can be used in its first state to conform to the acetabulum (or cup 12 disposed therein) and adjacent portions of the ilium and, optionally, the ischium. In particular, the surgeon can bend the trial member 52 while in its first state to form-fit around the adjacent portions of the acetabulum and ilium and optionally ischium to which attachment of the cage 2 is desired. After the trial member 52 has a form-fitting shape, the surgeon can transition the trial member 52 to a second state. After the trial member 52 is in the second state, the surgeon can remove the trial member 52 from the underlying anatomy and use the trial member 52 as a visual reference to bend the corresponding portions of the acetabular cage 2 into the desired shape. After the cage 2 has the desired shape as referenced to the trial member 52, the cage 2 can be positioned in and attached to the associated anatomy (and / or associated cup 12).It will be appreciated that the bending and shaping process of cage 2 using trial members 52 may be performed iteratively, whereby the surgeon may bend a portion of cage 2 based on visual reference to an associated portion of trial member 52, position the bent portion of cage 2 in contact with or close to the associated anatomical structure to visually reference the shape of cage 2 relative to the associated anatomical structure, and then move cage 2 away from the patient's anatomy for further visual reference with trial member 52, followed by bending.

[0040] The trial member 52 can be constructed of a material that can be activated on command to transition from a first state to a second state within a period of time suitable for intraoperative bending and molding. Preferably, the material of the trial member 52 is also suitable for rapid manufacturing. Non-limiting examples of such materials that are suitable for rapid manufacturing and can also be activated to a first or second state include polymeric materials, such as polylactic acid (PLA), poly(lactic-co-glycolic acid) (PLGA), and the like, as well as metals, such as titanium (e.g., commercially pure titanium), titanium alloys, stainless steel, and other medical grade metals. PLA, PLGA, and similar polymeric materials can be 3D printed in a neutral state and activated to a first (malleable) state by heating the material above its glass transition temperature. While in this first state, the surgeon can bend, mold, or otherwise form-fit the trial member 52 to the corresponding anatomical structure. The material is then solidified (i.e., cured) in the molded form, thereby providing a hardened, molded trial member 52 that the surgeon can use as a visual and tactile reference when bending and shaping the cage 2. In other embodiments, the material for the trial member 52 can be activated to the first or second state by application of UV light or other energy. In yet other embodiments, the material for the trial member 52 need not be 3D printable, but instead can be formed from a stock sheet material that can be cut, trimmed, or otherwise shaped to resemble the geometry of the cage 2. In other embodiments, the trial members 52 can be formed from stock sheets of PLA, PLGA, or similar material that are placed into a rapidly manufactured (e.g., 3D printed) mold and then molded in the mold to a shape that replicates the shape of the cage 2. In some embodiments, the material of the trial member 52 can be substantially transparent when in a neutral state and / or first state. In yet other embodiments, the stock sheet may be constructed from titanium, a titanium alloy, stainless steel, or another medical grade metal.It should also be understood that the trial members 52 need not have fixation holes 26a,b formed therein. Materials such as PLA and PLGA are valuable candidates for the construction of the trial members 52 because they can be 3D printed into the shape of the cage 2 or into a mold for vacuum forming the trial members 52, can be provided in sheet form, and are substantially transparent in a neutral state. It should be understood that the cage 2 and one or more trial members 52 can be included together in a kit, in which each trial member 52 can be a single-use trial member.

[0041] It should be understood that the various parameters of the implants described above, and associated techniques for constructing, processing, machining, bending, and shaping these implants, are provided as exemplary features for adapting the implant to substantially fit a patient's anatomy, and these parameters can be adjusted as needed without departing from the scope of the present disclosure.

[0042] It should be further understood that when a numerical preposition (e.g., "first," "second," "third") is used herein in reference to an element, component, dimension, or feature thereof (e.g., a "first" flange, a "second" flange, a "first" condition, a "second" condition), such numerical preposition is used to distinguish that element, component, dimension, and / or feature from another such element, component, dimension, and / or feature, and is not limited to the particular numerical preposition used in that instance. For example, a "first" member could also be referred to as a "second" member in a different context without departing from the scope of the present disclosure, so long as that element, component, dimension, and / or feature remains appropriately distinguished in the context in which the numerical preposition is used.

[0043] Although the present disclosure has been described in detail, it should be understood that various changes, substitutions, and alterations may be made herein without departing from the spirit and scope of the present invention as defined by the appended claims. Moreover, the scope of the present disclosure is not intended to be limited to the specific embodiments described herein. In particular, one or more of the features from the foregoing embodiments may be used in other embodiments herein. As one skilled in the art would readily appreciate from the process, any now existing or later developed machine, manufacture, composition of matter, means, method, or step that performs substantially the same function or achieves substantially the same result as the corresponding embodiment described herein may be utilized in accordance with the present disclosure.

[0044] [Embodiment] (1) An implantable device comprising: 1. An implantable device comprising: a portion, at least a majority of the portion, as measured by volume, comprising Ti64 alloy, the portion being capable of bending about a bending axis to a bend angle of at least about 50 degrees while maintaining structural integrity. (2) The implantable device of embodiment 1, wherein the portion is capable of bending about the bending axis to a bending angle of at least about 70 degrees while maintaining structural integrity. (3) The implantable device of embodiment 1, wherein the portion is capable of bending about the bending axis to a bending angle of at least about 90 degrees while maintaining structural integrity. (4) An implantable device as described in embodiment 1, wherein the portion is made of Ti64 alloy. (5) The implantable device of embodiment 1, wherein the portion has a thickness in the range of about 0.5 mm to about 3.0 mm.

[0045] (6) The implantable device of embodiment 5, wherein the thickness is in the range of about 0.9 mm to about 1.5 mm. (7) The implantable device of claim 1, wherein the portion comprises laser melted particles of Ti64 alloy having an alpha + beta phase lamellar grain structure. (8) An acetabular cage comprising: a dome for insertion into the acetabulum; a flange for attachment to a portion of the ilium; wherein the flange and the dome are integral with one another; An acetabular cage, wherein the dome and the flange are constructed from a Ti64 alloy, and at least a portion of the flange is capable of bending about a bending axis to a bending angle of at least about 90 degrees while maintaining structural integrity. (9) The acetabular cage of claim 8, wherein at least a portion of the flange has a thickness in the range of about 0.9 mm to about 1.5 mm. (10) An acetabular cage as described in embodiment 8, wherein the cage is composed of laser melted particles of Ti64 alloy.

[0046] (11) An acetabular cage as described in embodiment 10, wherein the cage has an overall packing density of at least 95 percent. (12) The acetabular cage of embodiment 8, wherein the flange defines a first surface and a second surface opposite the first surface, the flange defines at least one hole extending between the first and second surfaces and configured to receive a bone fixation member for attaching the flange to a bone, and the at least one hole extends along a central hole axis oriented at an angle relative to a transverse axis substantially perpendicular to the first and second surfaces at a location adjacent the at least one hole. (13) A method for producing an implant for implantation, comprising the steps of: 1. A method comprising bending a portion of the implant about a bend axis to a bend angle of at least about 50 degrees, wherein at least a majority of the portion, as measured by volume, comprises Ti64 alloy, and wherein the portion maintains structural integrity during and after the bending step. 14. The method of claim 13, wherein the bending step includes bending the portion about the bending axis to a bend angle of at least about 90 degrees. (15) The method of embodiment 14, wherein the implant is an acetabular cage having a dome for insertion into the acetabulum and a flange for attachment to a portion of the ilium, the dome and the flange being integral with one another, and the portion having a thickness in the range of about 1.2 mm to about 1.5 mm.

[0047] (16) The method of embodiment 13, further comprising bending one or more additional portions of the implant to have a shape that substantially conforms to a patient's anatomy, wherein the one or more additional portions of the implant are substantially made of Ti64. 17. The method of claim 16, further comprising the step of shaping the trial implant to fit the patient's anatomy prior to the bending and further bending steps. 18. The method of claim 17, further comprising the step of transitioning the trial implant from a neutral state to a malleable state prior to the shaping step, the shaping step being performed while the trial implant is in the malleable state. 19. The method of claim 18, further comprising, after the shaping step, transitioning the trial implant from the malleable state to a substantially rigid state in which the trial implant substantially maintains its shape. (20) The method of embodiment 19, further comprising the step of visually referencing the shape of the trial implant while performing the bending and further bending steps, the bending and further bending steps being performed to approximate the shape of the trial implant.

Claims

1. 1. An implantable device comprising:

1. An implantable device comprising: a portion, at least a majority of said portion, as measured by volume, comprising Ti64 alloy, said portion being capable of bending about a bending axis to a bend angle of at least about 50 degrees while maintaining structural integrity.

2. 10. The implantable device of claim 1, wherein said portion is capable of bending about said bending axis to a bend angle of at least about 70 degrees while maintaining structural integrity.

3. 10. The implantable device of claim 1, wherein said portion is capable of bending about said bending axis to a bend angle of at least about 90 degrees while maintaining structural integrity.

4. The implantable device of claim 1 , wherein said portion is comprised of a Ti64 alloy.

5. The implantable device of claim 1 , wherein the portion has a thickness in the range of about 0.5 mm to about 3.0 mm.

6. The implantable device of claim 5 , wherein the thickness ranges from about 0.9 mm to about 1.5 mm.

7. 10. The implantable device of claim 1, wherein said portion comprises laser melted grains of Ti64 alloy having an alpha+beta phase lamellar grain structure.

8. 1. An acetabular cage comprising: a dome for insertion into the acetabulum; a flange for attachment to a portion of the ilium; wherein the flange and the dome are integral with one another; An acetabular cage, wherein the dome and the flange are constructed from a Ti64 alloy, and at least a portion of the flange is capable of bending about a bending axis to a bending angle of at least about 90 degrees while maintaining structural integrity.

9. The acetabular cage of claim 8 , wherein said at least a portion of said flange has a thickness in the range of about 0.9 mm to about 1.5 mm.

10. The acetabular cage of claim 8 , wherein the cage is constructed from laser melted particles of Ti64 alloy.

11. The acetabular cage of claim 10 , wherein the cage has an overall packing density of at least 95 percent.

12. 9. The acetabular cage of claim 8, wherein the flange defines a first surface and a second surface opposite the first surface, the flange defines at least one hole extending between the first and second surfaces and configured to receive a bone fixation member for attaching the flange to a bone, the at least one hole extending along a central hole axis oriented at an angle relative to a transverse axis substantially perpendicular to the first and second surfaces at a location adjacent the at least one hole.

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