Flexible titanium alloy implants

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 processes for manufacturing such implants by rapid manufacturing to provide such implants with increased malleability.

BACKGROUND ART

[0002] In the field of rapid prototyping and additive manufacturing, many advances have been seen over the years, particularly for the rapid prototyping of articles such as prototype parts and mold dies. These advances have reduced manufacturing costs and time while improving the accuracy of the final product, as compared to conventional machining processes where material (e.g., metal) starts as a block of material and is subsequently machined down to the final product.

[0003] However, the main focus of rapid prototyping of three-dimensional structures such as surgical implants has been on increasing the density of structures produced by rapid prototyping. Examples of state-of-the-art 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. Particularly in the fields of selective laser sintering, selective laser melting, and 3D printing, improvements in the production of high-density parts have made these techniques useful for designing and accurately manufacturing articles such as high-density metal parts. However, these techniques often require post-forming treatments and / or finishing processes to provide prototyped parts with the mechanical properties (e.g., hardness, strength, malleability, toughness) necessary to meet the requirements demanded for various types of surgical implants.

SUMMARY OF THE INVENTION

MEANS FOR SOLVING THE PROBLEMS

[0004] According to one embodiment of the present disclosure, the embeddable device includes a portion configured such that, when measured by volume, at least the majority of the portion comprises a Ti64 (Ti-6Al-4V) alloy. Furthermore, this portion can be bent to a bending angle of at least about 50 degrees around a bending axis while maintaining structural integrity.

[0005] According to another embodiment of the present disclosure, the acetabular cage comprises 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 made of a Ti64 alloy. At least a portion of the flange can be bent to a bending angle of at least about 90 degrees around a bending axis while maintaining structural integrity.

[0006] According to additional embodiments of the present disclosure, a method for preparing an implant for implantation includes bending a portion of the implant to a bending angle of at least about 50 degrees around a bending axis. At least the majority of this portion, measured by volume, comprises a Ti64 alloy. This portion maintains structural integrity during and after the bending step. [Brief explanation of the drawing]

[0007] The above summary and the following detailed description of exemplary embodiments of this application will be better understood in conjunction with the accompanying drawings. For the purpose of illustrating the features of this application, exemplary embodiments are shown in the drawings. However, it should be understood that this application is not limited to the exact arrangements and means shown. These are shown in the drawings as follows: [Figure 1A] This is a perspective view of a surgical implant attached to a patient's anatomical structure according to one embodiment of the present disclosure. [Figure 1B] This is a perspective view of an implant attached to a patient's anatomical structure and a complementary second implant according to one embodiment of the present disclosure. [Figure 1C] Figure 1A is a perspective view of the implant shown. [Figure 1D]Figure 1A is another perspective view of the implant shown. [Figure 1E] These are perspective views of additional embodiments of surgical implants similar to the implant shown in Figure 1A, according to embodiments of the present disclosure. [Figure 1F] These are perspective views of additional embodiments of surgical implants similar to the implant shown in Figure 1A, according to embodiments of the present disclosure. [Figure 2A] Figure 1A is a perspective view of a partially fabricated version of the implant shown, in the construction direction of an example for a powder bed fabrication bed. [Figure 2B] This is a perspective view of a partially manufactured version of the implant shown in Figure 1A, shown in a different construction direction relative to the powder bed. [Figure 3A] These figures show enlarged views of exemplary grain structures of Ti64 alloys with increased malleability for use in implant construction. The grain structures shown in Figures 3A and 3B were produced in the same Ti64 material using slightly different custom heat treatment processes that allow for adjustment of the alpha phase lamellar size. For example, the average width of the alpha phase lamellae in Figure 3B is larger than that in Figure 3A. [Figure 3B] These figures show enlarged views of exemplary grain structures of Ti64 alloys with increased malleability for use in implant construction. The grain structures shown in Figures 3A and 3B were produced in the same Ti64 material using slightly different custom heat treatment processes that allow for adjustment of the alpha phase lamellar size. For example, the average width of the alpha phase lamellae in Figure 3B is larger than that in Figure 3A. [Figure 3C] Figure 3B shows an additional close-up view of the grain structure of a Ti64 alloy produced using the same custom heat treatment process used to generate the grain structure shown in Figure 3B. [Figure 3D] Figure 3B shows an additional close-up view of the grain structure of a Ti64 alloy produced using the same custom heat treatment process used to generate the grain structure shown in Figure 3B. [Figure 3E] This figure shows a magnified view of the crystal grain structure of a conventional sample of ISO 20160 alpha-beta titanium alloy. [Figure 4A] This chart shows the tensile test results of structural test members having a crystal grain structure substantially similar to that shown in Figures 3A-3B. [Figure 4B] This chart shows the tensile test results of structural test members having a crystal grain structure substantially similar to that shown in Figures 3A-3B. [Figure 5A] This chart compares bending test data of structural test members having a grain structure substantially similar to that shown in Figures 3A-3B with that of structural test members lacking the aforementioned grain structure. [Figure 5B] This is a photograph of the resulting bent structure test member, which has a grain structure substantially similar to the grain structure shown in Figures 3A-3B, after the bending test used to obtain the results shown in Figure 5A. [Figure 5C] These are photographs of the resulting bent structure test member, which lacks the grain structure shown in Figures 3A-3B, after the bending test used to obtain the results shown in Figure 5A. [Figure 5D] This chart compares additional bending test data for structural test members having a grain structure substantially similar to that shown in Figures 3A-3B with that of structural test members lacking the aforementioned grain structure. [Figure 6] This chart shows additional bending test data for structural test members of various thicknesses and with grain structures substantially similar to those shown in Figures 3A-3B. [Figure 7] This is an exploded perspective view of a surgical system having a flexible implant and a flexible, curable trial member according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0008] The present disclosure can be understood more readily by reference to the following detailed description, taken in connection with the accompanying drawings and examples, which form a part of the present disclosure. It is to be understood that the present disclosure is not limited to the particular apparatuses, methods, uses, conditions or parameters described and / or illustrated herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of examples 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 references to a specific numerical value include at least that specific value unless the context clearly dictates otherwise.

[0009] The term "titanium-based", as used herein for 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 a value is expressed in approximate form by the preceding "about", it will be understood that the particular value forms another embodiment. All ranges are inclusive of the boundary values and are combinable.

[0011] As used herein with respect to dimensions, angles, ratios, and other geometric shapes, the terms "approximately", "about", and "substantially" take manufacturing tolerances into account. Further, the terms "approximately", "about", and "substantially" can include 10% greater or lesser than the specified dimension, ratio, or angle. Furthermore, the terms "approximately", "about", and "substantially" may equally apply to the specific value specified.

[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, without departing from the scope of the embodiments disclosed herein, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0013] Embodiments disclosed herein relate to surgical implants made of titanium alloy having excellent strength and increased malleability that allows the implant to be bent intraoperatively, such as to shape it to conform to the anatomical structure of the patient. The surgical implants disclosed herein are also suitable for rapid manufacturing by additive manufacturing processes and subsequent heat treatment processes, configured to provide manufactured implants with increased malleability. Titanium (Ti) and various titanium alloys, particularly Ti64 (titanium-aluminum-vanadium alloy, also represented as Ti-6Al-4V), possess mechanical properties that make titanium alloys desirable for surgical implants, including strength, lighter weight (lower density) compared to other implant materials (e.g., stainless steel), durability, resistance to repeated loading, ability to withstand deformation (e.g., during internal fixation to the patient's anatomical structure), corrosion resistance, biocompatibility, and the ability to bond with bone. While titanium alloy implants possess many of these excellent properties, they tend to be difficult to bend, particularly during intraoperative shaping processes to match the shape of the implant to the patient's anatomical structure. However, the titanium alloy implants disclosed herein have a grain structure that provides implants with increased malleability, allowing them to be bent during surgery, such as to shape the implant to the anatomical structure of the patient in question. Non-limiting examples of surgical implant types that would benefit from the malleable titanium alloys disclosed herein include acetabular cages, craniofacial (CMF) plates, and trauma bone plates. The embodiments illustrated below of the manufacturing, processing, and finishing processes for implants, as well as methods of implant use, 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] Referring to Figures 1A to 1C, an exemplary implant 2 for hip joint repair is shown. The illustrated implant 2, referred to herein as the "acetabular cage" 2, is configured to be attached to the acetabulum 5 for repairing various acetabular defects in the pelvis 3. The cage 2 includes a socket portion or "dome" 4 shaped for insertion and attachment into the acetabulum 5. The cage 2 includes a first flange 6 extending from the dome 4 and configured for attachment to the ilium 7 of the pelvis 3. The first flange 6 is also referred to herein as the "iliac flange" 6. The iliac flange 6, in a portion thereof adjacent to the dome 4, also defines a bent portion 8, particularly an S-shaped bent portion ("S-bent portion") 8. The S-bent portion 8 is configured to adapt to 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 to the dome 4. The neck 15 is configured to facilitate engagement between the iliac flange 6 and the acetabular rim 11, and further to facilitate bending and / or twisting of the iliac flange 6 to match the patient's anatomical structure. The cage 2 may also include an optional second flange 10 extending from the dome 4 at a position generally opposite to the iliac flange 6 and configured for attachment to the ischium 9 of the pelvis 3. The second flange 10 is also referred to herein as the "ischial flange" 10. In other embodiments, as shown in Figure 1E, the cage 2 may be formed to have the iliac flange 6 but lack the ischial flange.

[0015] It should be understood that the dome 4 can 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 portion thereof that has been reamed or otherwise surgically modified), as shown in Figure 1A, and can also be configured to seat within the acetabular cup 12 that is in direct contact with the acetabular surface, as shown in Figure 1B. The cage 2 is malleable enough to allow the surgeon to manipulate, bend, and shape portions of it to conform to the shape of the adjacent patient's anatomical structure. In particular, the iliac flange 6 and the optional ischial flange 10 can be bent and shaped to have contours that match the relevant contours of the ilium 7 and ischium 9, respectively. One or more portions of the cage 2 can 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] Referring here to Figures 1C to 1D, the cage 2 has a first surface or inner surface 14 configured to face the pelvis when implanted, and a second surface or outer surface 16 on the opposite side configured to face away from the pelvis 3 when implanted. The cage 2 defines a thickness T measured along a direction perpendicular to them between 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 specifically in the range of about 0.9 mm to about 2.2 mm, and more specifically 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 may have a reduced thickness compared to various other portions of the cage 2. In such embodiments, portions having reduced thickness may be configured to facilitate bending and shaping along such portions.

[0017] The cage 2 has a first end or upper end 18 located at the end of the iliac flange 6, and a second end or lower end 20 located at the end of the ischial flange 10 in embodiments having the ischial flange 10. In embodiments lacking the ischial flange, the lower end 20 of the cage 2 may be at the lowest edge of the dome 4. The cage 2 has an anterior side 22 and an opposite posterior side 24. When terms indicating anatomical directions such as “medial,” “lateral,” “super,” “down,” “anterior,” and “posterior” are used herein in reference to implants such as the acetabular cage 2, it should be understood that they generally refer to the relative position of the implant such that it is configured to face that direction when the implant is embedded.

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

[0019] As shown in Figure 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 the transverse axis 29, which extends orthogonally through the inner and outer surfaces 14, 16 of the cage 2 adjacent to the hole 26a. Such holes 26a may be called “inclined holes”. It should be understood that one or more flange holes 26a, including inclined and non-inclined holes 26a, may have threads or other locking structures 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 understood that including at least one inclined flange hole 26a can provide significant advantages to the cage 2. One such advantage is that the angle A1 of the hole 26a can be adjusted to provide a target insertion trajectory for the associated bone screw. In this configuration, the angle A1 may be suitable for adjusting the insertion trajectory to a specific geometric shape of the target portion of the bone, thereby providing enhanced fixation to the target portion of the bone. For example, the angle A1 of the hole 26a on the iliac flange 6 can be adapted to provide an insertion trajectory that is tailored to the specific geometry of the target portion of the ilium, such as an insertion trajectory that is substantially parallel to the bone material in the target iliac portion. In this configuration, the angle A1 can be adapted to increase the efficiency of the bone screw biting into or otherwise engaging with the target bone. Another advantage of the inclined hole 26a is that the angle A1 can be adapted to reduce the amount of soft tissue destruction (e.g., incision, excision, and / or contraction) adjacent to the hole 26a. For example, the angle A1 of the hole 26a in the iliac flange 6 can be adapted to reduce the amount of gluteal muscle resection required to attach the iliac flange 6 to the relevant portion of the ilium.

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

[0021] Selected portions of the cage 2 may 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 may have ridges for pressing into the underlying bone in a manner that enhances fixation. Additionally or alternatively, the material of the cage 2 along one or more selected portions of the inner surface 18 may be porous, i.e., it may have a porous three-dimensional (3D) structure defining a very large number of holes, which can be adjusted according to various design purposes, such as, in non-limiting examples, to promote internal bone growth into the holes to enhance postoperative fixation with the underlying bone. Features of the porous structure, including variations of such features, will be described in more detail below.

[0022] The implants of this disclosure, such as cage 2 in the embodiments illustrated herein, are composed of titanium alloys, particularly titanium-aluminum-vanadium alloy: Ti-6Al-4V ("Ti64"). This particular titanium alloy (Ti64) is advantageous for the construction of implants because Ti64 is stronger and more fatigue-resistant than titanium (including the "commercially pure" titanium (Ti-CP) grade) and other titanium alloys. However, conventional implants composed of Ti64, such as acetabular cages, are difficult for surgeons to bend during surgery, particularly in bending areas, without forming cracks. The heat treatment process described below demonstrates the ability to increase the malleability of implants composed of Ti64 so that these cages 2 can be bent during surgery, for example, by a surgeon, without losing structural integrity. In this way, the inventors have discovered a technique that makes it possible to employ the strength and durability of Ti64 in surgical implants (e.g., acetabular cage 2) that are also bendable, which represents a significant advance in the field of surgical implant technology.

[0023] The use of Ti64 as an implant material also makes it possible to manufacture the cage 2 by rapid manufacturing through additive manufacturing processes, such as laser-activated powder bed fusion (PBF) processes, which form the cage 2 into the desired preoperative shape. The characteristics of the implant manufacturing and finishing processes are described below.

[0024] The geometric shape of cage 2 is created in a three-dimensional (3D) virtual space, thereby providing a 3D virtual model of cage 2. After the 3D virtual model of cage 2 is created, a physical version of cage 2 having the geometric shape and features of the 3D virtual model can be manufactured using a rapid additive manufacturing process. The 3D virtual model of cage 2 can optionally be designed with the assistance of patient scan data of the specific anatomical structure to which cage 2 will be attached. Such patient scan data may, as a non-limiting example, include a series of CT scan cross-sections of the acetabulum and the adjacent portions of the ilium 7 and ischium 9. In particular, the iliac flange 6 and the optional ischial flange 10 can be adjusted in the 3D virtual space to have contours corresponding to the contours of the respective portions of the ilium 7 and ischium 9 to which flanges 6 and 10 will be attached. After the 3D virtual model of cage 2 is created, a cage 2 with the adjusted patient-specific 3D virtual geometry can be manufactured using a rapid additive manufacturing process.

[0025] Cage 2 can be constructed using a laser-activated PBF process, also known as a laser melting process, which encompasses selective laser sintering (SLS) and selective laser melting (SLM) processes. A non-limiting example of a laser melting process for constructing Cage 2 is described below. First, thin powder layers are distributed onto a workbench (often called a “build platform”) so that at least one powder layer forms a powder bed. The powder contains constituent particles of Ti64 material, which can be 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 mean a structure formed by fusing the particles in the powder bed together by the PBF process. A selected area of ​​the top surface of the powder layer (the “build surface”) is melted by exposure to a directional energy source, typically a laser beam. Thus, the exposure pattern of the laser beam forms a cross-section of the three-dimensional object. Cage 2 is constructed by continuous fusion, stacking the thus formed cross-sections layer by layer along the vertical direction. Between the fusions of each layer, the construction platform is incremented downward, and a new layer of powder is deposited on the construction surface. These steps (e.g., lowering the workbench, distributing the new powder layer onto the powder bed, and exposing the new powder layer to the laser source 1) are repeated layer by layer as needed, resulting in the creation of cage 2 as multiple cross-sectional layers that are continuously fused. It should be understood that the laser fusion process can also be characterized as a 3D printing process. Therefore, the term “constructed” can be used herein synonymously with the term “printed.”

[0026] During the PBF process, the cage 2 can be constructed in various orientations on the power bed. Two non-limiting examples of such construction orientations are shown in Figures 2A and 2B. As shown in Figure 2A, the cage 2 can be constructed such that the outer surface 16 faces downwards towards the powder layer (and the inner surface 14 faces upwards towards the powder layer). Alternatively, as shown in Figure 2B, the cage 2 can be constructed such that the front side 22 faces downwards (and the rear side 24 faces upwards) on the powder bed. In either of these construction orientations (and in the other), the cage 2 can be constructed with the base member 30 of the stock material facing downwards, which can be used as a support structure during the post-construction process and subsequently removed. As shown, the cage 2 can be constructed on the powder bed without fixing holes, which can then be formed in the cage 2 during a machining process, for example, by a multi-axis computer numerical control (CNC) machine. In other embodiments, the cage 2 may be constructed to have fixing holes, which may be further machined and finished in subsequent machining processes. During the PBF process, the dome 4 may optionally be constructed without a support structure (i.e., stock material) beneath it, as shown in the figure. In other embodiments, the dome 4 may be constructed to have a support structure beneath it, which is subsequently removed.

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

[0028] After cage 2 is constructed, cage 2 is subjected to one or more processing processes, such as one or more heat treatment processes, in order to modify the grain structure of the as-printed Ti64 implant material in a manner that increases the malleability of cage 2, in particular to allow the surgeon to bend that portion of cage 2 in surgery without causing cracks, breakage, or other mechanical failures in that portion. Specifically, in order to provide the increased malleability disclosed herein, the grain structure of Ti64 is changed from the as-printed metastable martensite structure to a lamellar alpha+beta phase with adjustable lamellar size. Referring here to Figures 3A-3D, the resulting grain structures in Ti64 samples printed and processed according to embodiments herein are shown. For example, Figures 3A and 3B show enlarged views of exemplary grain structures of respective printed Ti64 alloy samples, prepared by using Ti64 powder having 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 lamellars α in Figure 3B is larger than that in Figure 3A, suggesting that the size of the alpha phase lamellars α can be adjusted, particularly increased (which has been observed to increase malleability). Referring here to Figures 3C and 3D, additional enlarged views show the grain structure produced using the same custom heat treatment process used to produce the grain structure shown in Figure 3B. It should be understood that the alpha phase lamellars α have a larger increased width Wα than the conventional Ti64 grain structure.

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

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

[0031] The constructed and treated cage 2 demonstrates superior malleability compared to conventional Ti64 components of similar thickness. Referring here to Figures 4A-4B, two sets of tensile test results are shown for printed and finished Ti64 tensile test rods fabricated using a modified heat treatment. In Figure 4A, six specimens of printed and finished Ti64 cylinders were subjected to tensile tests at room temperature to measure the following four qualities: (1) ultimate tensile strength (measured in megapascals (MPa)), (2) yield strength at 0.2% offset (also known as the 0.2% proof stress test) (measured in MPa), (3) elongation after fracture (%), and (4) area loss (%). For comparison, the minimum tensile requirements for these four qualities, according to ASTM F3001-14 Class A, are also listed. In Figure 4B, three printed and treated Ti64 cylinder specimens were subjected to similar tensile tests, measuring the same four qualities as those measured in Figure 4A: (1) ultimate tensile strength ("UTS") (measured in MPa), (2) yield strength at a 0.2% offset ("0.2% proof stress test") (measured in MPa), (3) elongation after fracture ("elongation A%"), and (4) area loss percentage ("area loss Z%"). It should be noted that the specimens shown in Figure 4B were subjected to slightly different heat treatment parameters than those shown in Figure 4A. The results shown in Figures 4A and 4B demonstrate that the printed and treated Ti64 specimens measured significantly higher elongation, specifically elongation of approximately 15% to 23%, at the slight expense of yield strength and ultimate tensile strength. It should be noted that an elongation of 15-23% represents a significant advantage over prior art 3D-printed Ti64 structures.

[0032] Referring here to Figures 5A-5C, the results of three-point bending tests performed on five different samples of plate-shaped test coupons are shown: (1) "Ti CP2 Annealed 1.34mm" (annealed commercial pure (CP) grade 2 titanium with a thickness of 1.34mm), (2) "Ti CP2 Stress Relaxed 1.34mm" (stress relaxed commercial pure (CP) grade 2 titanium with a thickness of 1.34mm), (3) "Ti CP2 Annealed 1.57mm" (annealed commercial pure (CP) grade 2 titanium with a thickness of 1.57mm), (4) "Ti64 CHT 1.34mm" (heat-treated (custom heat-treated (CHT)) Ti64 alloy with a thickness of 1.34mm), and (5) "Ti64 HIP 1.34mm" (heat-treated by hot isostatic pressing (HIP) Ti64 alloy with a thickness of 1.34mm). The test coupons for samples (1) to (5) were fabricated by rapid manufacturing using a laser melting PBF process, with a length of approximately 50 mm and a width of 20 mm. Each sample was subjected to a bending displacement target of 8 mm, corresponding to a bending angle of more than 90 degrees, using a test setup consistent with the requirements of ASTM E290, and the displacement versus applied force was plotted. Furthermore, bending tests were performed by bending the test coupons around a mandrel with a diameter of 5 mm.

[0033] As shown in Figure 5A, specimen (4) (Ti64 CHT 1.34 mm) was able to bend to a full test displacement (equal to a minimum bending angle of 90 degrees) with a maximum applied force of approximately 3.25 kN, which is sufficient for cage 2 (especially its flange) of the same thickness to be bent intraoperatively by a surgeon to match the shape of cage 2 to the anatomical structure of the relevant patient. These results are comparable to those of specimens made of commercially pure titanium, especially considering the increased strength of Ti64 compared to commercially pure titanium. As shown in Figure 5B, the three test subjects of specimen (4) coupon showed clean bending and maintained structural integrity (meaning the specimen showed no signs of mechanical failure such as cracking, delamination, or other failure modes). As demonstrated in these tests, the hot-pressed (HIP) Ti64 specimen experienced crack fracture at a displacement of approximately 3.75 mm (applied force of approximately 2.75 kN), as shown in Figure 5A, and the crack can be seen in Figure 5C. These results demonstrate that implants constructed from Ti64 and custom heat-treated have superior bending properties compared to those constructed from HIP Ti64.

[0034] Referring to Figure 5D, further bending tests show that cage thickness is a key factor in flexibility. The results shown in Figure 5D are for three different test coupons: (6) "Ti64 CHT 1.34mm" (a heat-treated Ti64 alloy with a thickness of 1.34mm (same sample parameters as sample (4) shown in Figure 5A)), (7) "Ti64 CHT 1.64mm" (a heat-treated Ti64 alloy with 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 Figures 5A-5C, performed on annealed commercial pure (CP) grade 2 titanium with a thickness of 1.89 mm. These results demonstrate that increasing the thickness of the heat-treated Ti64 specimen from 1.34 mm to 1.64 mm (an increase of 0.3 mm) can cause fracture at a displacement of approximately 5 mm (and a bending force of 4.0 kN). These results indicate that, for an acetabular cage 2 constructed of this material (heat-treated Ti64), the portion of the cage 2 adapted for bending (e.g., the iliac flange 6 and / or an optional ischial flange 10) should be formed with a thickness of less than 1.64 mm, preferably close to 1.5 mm.

[0035] Referring to Figure 6, further bending tests showed that implant thicknesses up to approximately 1.5 mm could be bent to a target test displacement of approximately 8 mm (equivalent to a bending angle greater than 90 degrees, using a test setup consistent with the requirements of ASTM E290) without breakage. In these bending tests, four sample groups of test coupons with thicknesses of 0.9 mm, 1.1 mm, 1.3 mm, and 1.5 mm were subjected to the same three-point bending tests as described above, with reference to Figures 5A-5D. Each sample group shown in Figure 6 contained eight test coupons of their respective thicknesses. As shown in the figure, each of these sample groups was able to achieve the target test displacement (8 mm, 90+ degrees) without breakage.

[0036] As mentioned above, the flexible Ti64 acetabular cage 2 disclosed herein provides the strength and other relevant advantages of Ti64, and also allows the surgeon to bend a portion of the cage 2 during surgery if it is necessary to match the patient's anatomical structure. During hip repair surgery, such as surgery to treat acetabular defects, including type 2A, type 2B, type 2C, type 3A, or type 3B acetabular defects, the surgeon can expose and prepare the acetabulum to receive the acetabular cup 12 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-hole cup 12 into the acetabulum in the desired orientation. Subsequently, the surgeon can move the acetabular cage 2 to a position adjacent to the cup 12, in particular 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 of the dome 4 aligns with at least one corresponding hole of the cup 12. With the cage 2 in such a position, the surgeon can bend and shape the iliac flange 6 so that it has a contour approximately equal to the contour of the portion of the ilium with which it is in contact.

[0037] It should be understood that the surgeon does not need to maintain the cage 2 in contact with or close to the cup 2 while bending the iliac flange 6 into the desired shape. The surgeon may choose to move the cage 2 to a position where the iliac flange 6 is visually referenced relative to the corresponding portion of the ilium, and then move the cage 2 to a more comfortable position for bending. This bending and shaping process can also be repeated, thereby allowing the surgeon to bring the cage 12 into contact with and / or close to the cup 12 in order to visually reference the iliac flange 6 relative to the corresponding portion of the ilium, then move the cage 2 to a more comfortable position for bending, and then return the cage 2 to contact with or close to the cup in order to further visually reference the iliac flange 6 relative to the corresponding portion of the ilium, and these steps can be repeated until a satisfactory contour and shape is imparted to the iliac flange 6.

[0038] Furthermore, if the selected cage 2 includes an ischial flange 10, the surgeon can bend and shape the ischial flange 10 so that it has a contour approximately equal to the contour of the portion of the ischium that the ischal flange 10 contacts. It should be understood that the surgeon can use steps similar to those described above for shaping the iliac flange 6 to shape the ischial flange 10. To attach the cage 2 and cup 12 to the acetabulum, the surgeon can insert locking members, such as bone screws, through one or more of the aligned holes in the dome 4 and cup 12. To attach the iliac flange to the corresponding portion of the ilium, the surgeon can also insert one or more additional locking members, such as bone screws, into the underlying bone through one or more holes 26a in the iliac flange 6. If the selected cage 2 includes an ischial flange 10, the surgeon can also insert one or more additional locking members, such as bone screws, into the underlying bone through one or more holes 26a in the ischial flange 10 to attach the ischial flange 10 to the corresponding portion of the ischium. Additionally or alternatively, if the selected cage 2 includes an ischial flange 10, the surgeon may insert part and, at most, all of the ischial flange 10 into the ischium by drilling or otherwise creating a slot or opening in the ischium and inserting the ischial flange 10 therein. It should be understood that the surgeon may choose to attach a specific portion of the cage 2 to a lower layer of bone such as the dome 4 and to shape separate portions of the cage 2, such as the iliac flange 6 and / or ischial flange 10, to the corresponding bone.

[0039] Referring here to Figure 7, the trial system 100 for shaping the acetabular cage 2 may include a trial member 52, which is configured to be manipulated, bent, or otherwise shaped in a substantially conformal manner with the relevant anatomical structure 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 conform to the contour of the anatomical structure beneath it. 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 configuration, the surgeon can use the trial member 52 during surgery 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 fit the acetabulum (or the cup 12 placed therein) and the adjacent portions of the ilium and optionally the ischium. In particular, the surgeon can bend the trial member 52 to form-fit around the acetabulum and ilium and optionally the ischium adjacent to the acetabulum where the cage 2 is to be attached, while it is in its first state. After the trial member 52 has a form-fit shape, the surgeon can move 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 anatomical structure and use the trial member 52 as a visual reference for bending the corresponding portion of the acetabular cage 2 into the desired shape. After the cage 2 has taken the desired shape, as referenced with respect to the trial member 52, the cage 2 can be positioned and attached to the relevant anatomical structure (and / or the relevant cup 12).It should be understood that the bending and shaping process of the cage 2 using the test member 52 can be repeated, thereby allowing the surgeon to bend a portion of the cage 2 based on a visual reference to the relevant portion of the test member 52, positioning the bent portion of the cage 2 in contact with or close to the relevant anatomical structure in order to visually reference the shape of the cage 2 with respect to the relevant anatomical structure, and then, for further visual reference with the test member 52, the cage 2 may be moved away from the patient's anatomical structure and then bent.

[0040] The test member 52 may be made of a material that can be activated to transition from a first state to a second state within a period suitable for bending and shaping during surgery, as per instructions. Preferably, the material of the test member 52 is also suitable for rapid manufacturing. Non-limiting examples of such materials that are suitable for rapid manufacturing and can be activated to the first or second state include polymer materials, e.g., polylactic acid (PLA), poly(lactic acid-coglycolic acid) (PLGA), and metals, e.g., titanium (e.g., commercially pure titanium), titanium alloys, stainless steel, and other medical-grade metals. PLA, PLGA, and similar polymer materials can be 3D printed in a neutral state and can be activated to a first (malleable) state by heating the material above its glass transition temperature. While in this first state, the surgeon can bend, shape, or otherwise form-fit the test member 52 to the corresponding anatomical structure. The material is then solidified (i.e., cured) in the molded form, thereby providing a cured and molded trial member 52 that can be used as a visual and tactile reference when a surgeon bends and shapes the cage 2. In other embodiments, the material for the trial member 52 can be activated to a first or second state by the application of UV light or other energy. In yet another embodiment, the material for the trial member 52 does not need to be 3D printable, but can instead be formed from a stock sheet material that can be cut, trimmed, or otherwise molded to resemble the geometric shape of the cage 2. In other embodiments, the trial member 52 can be formed from a stock sheet of PLA, PLGA, or similar material, which is placed in a mold manufactured by rapid manufacturing (e.g., 3D printed) and then molded in the mold to replicate the shape of the cage 2. In some embodiments, the material for the trial member 52 may be substantially transparent when in a neutral state and / or a first state. In further embodiments, the stock sheet may be constructed from titanium, titanium alloy, stainless steel, or another medical-grade metal.It should also be understood that the test member 52 does not need to have fixing holes 26a, b formed therein. Materials such as PLA and PLGA are useful candidates for the constituent materials of the test member 52 because they can be 3D printed into the shape of the cage 2 or into a mold for vacuum forming the test member 52, can be supplied in sheet form, and are substantially transparent in a neutral state. It should also be understood that the cage 2 and one or more test members 52 can be included together in a kit, in which case each test member 52 may be a single-use test member.

[0041] It should be understood that the various parameters of the implants described above, as well as the related techniques for constructing, processing, machining, bending, and shaping these implants, are provided as exemplary features for adapting the implants to substantially conform to the patient's anatomical structure. These parameters can be adjusted as necessary without departing from the scope of this disclosure.

[0042] Where numerical prepositions (e.g., "first," "second," "third") are used in this specification with respect to elements, components, dimensions, or features thereof (e.g., "first" flange, "second" flange, "first" state, "second" state), it should be further understood that such numerical prepositions are used to distinguish such element, component, dimension, and / or feature from another such element, component, dimension, and / or feature, and are not limited to the specific numerical preposition used in that case. For example, a "first" member may be referred to as a "second" member in a different context without departing from the scope of this disclosure, as long as the element, component, dimension, and / or feature remains appropriately distinguishable in the context in which the numerical preposition is used.

[0043] While this disclosure has been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Furthermore, the scope of this disclosure is not intended to be limited to the specific embodiments described herein. In particular, one or more features from the embodiments described above may be used in other embodiments herein. Compositions, means, methods, or processes of machines, products, materials that currently exist or will be developed that perform substantially the same function or achieve substantially the same results as the corresponding embodiments described herein may be used in accordance with this disclosure, as will be readily apparent to those skilled in the art from the processes.

[0044] [Implementation Method] (1) An implantable device, An embeddable device comprising a portion, the portion having at least a majority of which, when measured by volume, comprises a Ti64 alloy, and the portion being able to bend to a bending angle of at least about 50 degrees around a bending axis while maintaining structural integrity. (2) The embeddable device according to Embodiment 1, wherein the portion can be bent to a bending angle of at least about 70 degrees around the bending axis while maintaining structural integrity. (3) The embeddable device according to Embodiment 1, wherein the portion can be bent to a bending angle of at least about 90 degrees around the bending axis while maintaining structural integrity. (4) The embeddable device according to Embodiment 1, wherein a portion of the device is made of a Ti64 alloy. (5) The implantable device according to Embodiment 1, wherein the portion has a thickness in the range of approximately 0.5 mm to approximately 3.0 mm.

[0045] (6) The embeddable device according to Embodiment 5, wherein the thickness is in the range of approximately 0.9 mm to approximately 1.5 mm. (7) The embeddable device according to Embodiment 1, wherein the portion comprises laser-melted particles of a Ti64 alloy having an alpha-beta phase lamellar grain structure. (8) Acetabular cage, A dome for insertion into the acetabulum, A flange for attaching to a part of the ilium, The flange and the dome are integral to each other, An acetabular cage in which the dome and the flange are made of Ti64 alloy, and at least a portion of the flange can be bent to a bending angle of at least about 90 degrees around a bending axis while maintaining structural integrity. (9) The acetabular cage according to Embodiment 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) The acetabular cage according to Embodiment 8, wherein the cage is composed of laser-melted particles of Ti64 alloy.

[0046] (11) The acetabular cage according to Embodiment 10, wherein the cage has a total filling density of at least 95 percent. (12) The acetabular cage according to Embodiment 8, wherein the flange defines a first surface and a second surface opposite to the first surface, the flange defines at least one hole extending between the first surface and the second surface 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 to a transverse axis substantially perpendicular to the first surface and the second surface at a position adjacent to the at least one hole. (13) A method for manufacturing an implant for implantation, A method comprising the step of bending a portion of the implant to a bending angle of at least about 50 degrees around a bending axis, wherein at least the majority of the portion, when measured by volume, comprises a Ti64 alloy, and the portion maintains structural integrity during and after the bending step. (14) The method according to embodiment 13, wherein the bending step includes bending the portion to a bending angle of at least about 90 degrees around the bending axis. (15) The method according to 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 each other 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 the step of bending one or more additional portions of the implant to have a shape substantially conforming to the anatomical structure of a patient, wherein the one or more additional portions of the implant are substantially made of Ti64. (17) The method of Embodiment 16, further comprising the step of shaping the trial implant to conform to the anatomical structure of the patient before the bending step and the further bending step. (18) The method of Embodiment 17, further comprising a step of transitioning the trial implant from a neutral state to a malleable state before the molding step, wherein the molding step is performed while the trial implant is in the malleable state. (19) The method of Embodiment 18, further comprising the step of moving the trial implant from the malleable state to a substantially rigid state in which the trial implant substantially maintains its shape, after the molding step. (20) The method according to Embodiment 19, further comprising the step of visually referring to the shape of the trial implant while performing the bending step and the further bending step, wherein the bending step and the further bending step are performed to bring the implant closer to the shape of the trial implant.

Claims

[Claim 1] It is an acetabular cage, A dome for insertion into the acetabulum, A flange for attaching to a part of the ilium, The flange and the dome are integral to each other, The dome and the flange are made of Ti64 alloy, and at least a portion of the flange has a thickness in the range of 0.9 mm to 1.5 mm. Acetabular cage, 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 surface and the second surface 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 to a transverse axis substantially perpendicular to the first surface and the second surface at a position adjacent to the at least one hole.

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