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 a Ti64 (Ti-6AI-4V) alloy. Additionally, the portion is bendable about a bending axis to a bending 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 methods for rapidly manufacturing such implants and providing such implants with increased ductility. Background Art

[0002] Over the years, many advances have been made in the field of rapid prototyping and additive manufacturing, especially for the rapid prototyping of articles such as prototype parts and molded molds. These advances have reduced manufacturing costs and time while increasing the precision of the finished product compared to conventional machining processes such as those in which a material (e.g., metal) begins as a block of material and is then machined into a finished product.

[0003] However, rapid prototyping three-dimensional structures (such as surgical implants) have mainly focused on the density increase of rapid prototyping structures. The example of modern rapid prototyping / additive manufacturing technology includes 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 drawing. Especially in the field of selective laser sintering, selective laser melting and 3D printing, the improvement of high-density component production makes those technologies available for designing and accurately producing products such as high-density metal parts. However, those technologies usually require post-forming processing and / or finishing processes to provide the molded parts with the necessary mechanical properties (e.g., hardness, strength, ductility, toughness) required to meet the requirements required for various types of surgical implants. Summary of the invention

[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 a Ti64 (Ti-6Al-4V) alloy. Additionally, the portion can be bent about a bending axis to a bending angle of at least about 50 degrees 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 and for attachment to a portion of the ilium. The dome and the flange are constructed of a Ti64 alloy. At least a portion of the flange can be bent about a bending axis to a bending angle of at least about 90 degrees 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 around a bending axis to a bending angle of at least about 50 degrees. At least a majority of the portion as measured by volume comprises a Ti64 alloy. The portion maintains structural integrity during and after the bending step. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The foregoing summary of the invention and the following detailed description of exemplary embodiments of the present application will be better understood when read in conjunction with the accompanying drawings. In order to illustrate the characteristic parts of the present application, exemplary embodiments are shown in the accompanying drawings. However, it should be understood that the present application is not limited to the precise arrangements and means shown. In the accompanying drawings:

[0008] Figure 1A is a perspective view of a surgical implant attached to a patient's anatomy according to an embodiment of the present disclosure;

[0009] Figure 1B is a perspective view of an implant attached to a complementary second implant and to a patient's anatomy according to an embodiment of the present disclosure;

[0010] Figure 1C yes Figure 1A A perspective view of an implant illustrated in FIG.

[0011] Figure 1D yes Figure 1A Another perspective view of the implant illustrated in;

[0012] Figure 1E and Figure 1F are each according to an embodiment of the present disclosure and Figure 1A A perspective view of an additional embodiment of a surgical implant similar to the implant shown in ;

[0013] Figure 2A is shown in an example build orientation relative to an AM powder bed Figure 1A A perspective view of a partially manufactured version of the implant illustrated in FIG.

[0014] Figure 2B is shown in an alternative build orientation relative to the powder bed Figure 1A A perspective view of a partially manufactured version of the implant illustrated in FIG.

[0015] Figure 3A and Figure 3B shows an enlarged view of an exemplary grain structure of a Ti64 alloy having increased ductility for implant construction; Figure 3A and Figure 3B The grain structure shown in was produced in the same Ti64 material using a slightly different custom heat treatment process, which allows the size of the α-phase flakes to be customized; for example, Figure 3B The average width of the α-phase flakes in Figure 3A The average width of the α-phase flakes in

[0016] Figure 3C and Figure 3D shows the use for production Figure 3BAdditional magnified view of the grain structure of the Ti64 alloy produced by the same custom heat treatment process as the grain structure shown in;

[0017] Figure 3E An enlarged view showing the grain structure of a prior art sample of an ISO 20160 alpha+beta titanium alloy;

[0018] Figure 4A and Figure 4B is shown with FIG. 3A to FIG. 3B a graph of tensile test results of structural test members having a grain structure substantially similar to the grain structure illustrated in;

[0019] Figure 5A is to have FIG. 3A to FIG. 3B a graph of bend test data comparing a structural test member having a grain structure substantially similar to the grain structure illustrated in FIG. 1 to a structural test member lacking the aforementioned grain structure;

[0020] Figure 5B is used to generate Figure 5A The results of the bending test shown in the example have been FIG. 3A to FIG. 3B A photograph of a resulting flexural test member having a grain structure substantially similar to that illustrated in;

[0021] Figure 5C is used to generate Figure 5A The exemplified results are missing after the bending test FIG. 3A to FIG. 3B A photograph of the resulting flexural structure test member of the grain structure illustrated in;

[0022] Figure 5D is to have FIG. 3A to FIG. 3B a graph of additional bend test data comparing a structural test member having a grain structure substantially similar to the grain structure exemplified in FIG. 1 to a structural test member lacking the aforementioned grain structure; and

[0023] Figure 6 is shown with various thicknesses and with FIG. 3A to FIG. 3B a graph of yet additional bend test data for a structural test member having a grain structure substantially similar to the grain structure illustrated in FIG. 1 ; and

[0024] Figure 7 is an exploded perspective view of a surgical system having a bendable implant and a bendable, hardenable trial member according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] The present disclosure may be more readily understood with reference to the following detailed description in conjunction with the accompanying drawings and examples that form a part of the present disclosure. It should be understood that the present disclosure is not limited to the specific devices, methods, applications, conditions or parameters described and / or shown herein, and that the terms used herein are only used for the purpose of describing specific embodiments by way of example, and are not intended to limit the scope of the present disclosure. In addition, unless the context clearly indicates otherwise, as used in this specification (including the appended claims), the singular forms "a", "an" and "the" include the plural, and when referring to a specific numerical value, at least this specific value is included.

[0026] As used herein, the term "titanium-based" with respect to an object such as an implant means consisting primarily of titanium (Ti) or a titanium alloy.

[0027] As used herein, the term "plurality" means more than one. When a range of values ​​is expressed, another embodiment includes from one specific value and / or to other specific values. Similarly, when a value is expressed as an approximation using "about", it should be understood that the specific value of the value constitutes another embodiment. All ranges are inclusive and combinable.

[0028] As used herein, the terms "approximately," "about," and "substantially" with respect to dimensions, angles, ratios, and other geometric shapes take into account manufacturing tolerances. In addition, the terms "approximately," "about," and "substantially" may include 10% greater or less than the stated dimension, ratio, or angle. Furthermore, the terms "approximately," "about," and "substantially" may apply equally to the specific values ​​stated.

[0029] It should be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. Instead, these terms are used to distinguish one element from another element. 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.

[0030] Embodiments disclosed herein relate to titanium alloy surgical implants, which have excellent strength and increased ductility, which allows implants to bend during surgery, such as for being formed to correspond to associated patient anatomical structures. Surgical implants disclosed herein are also suitable for rapid manufacturing via additive manufacturing processes and subsequent heat treatment processes configured to provide increased ductility to manufactured implants. Titanium (Ti) and various titanium alloys (particularly Ti64 (titanium-aluminum-vanadium alloy, also expressed as Ti-6Al-4V)) have mechanical properties that make them desirable for surgical implants, including strength, lighter weight (lower density) compared to other implant materials (e.g., stainless steel), durability, resistance to repeated loads, ability to withstand strain (e.g., during internal fixation to patient anatomical structures), corrosion resistance, biocompatibility, and the ability to combine with bone. Although titanium alloy implants have many of these excellent properties, they are often difficult to bend, particularly during the intraoperative shaping process for matching implant shape with patient anatomical structures. However, the titanium alloy implants disclosed herein have grain structures that provide increased ductility to the implants, which allow intraoperative bending, such as for shaping the implants to associated patient anatomy. Non-limiting examples of surgical implant types that benefit from the ductile titanium alloys disclosed herein include acetabular cages, craniomaxillofacial (CMF) plates, and traumatic bone plates. Although the following illustrative embodiments of the manufacturing, processing, and finishing processes and methods used for implants relate to acetabular cages, it should be understood that the processes, methods, and structures disclosed herein can be used to construct and use many other types of implants.

[0031] refer to Figures 1A to 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 constructed 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 to be inserted and attached to the acetabulum 5. The cage 2 also includes a first flange 6, which extends from the dome 4 and is constructed to be attached 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 also defines a bend 8, particularly an S-shaped bend ("S-bend") 8, at a portion of the iliac flange near the dome 4. The S-bend 8 is configured to accommodate and roughly conform to the geometry of the acetabular rim (edge) 11 and the ilium body 13. The iliac flange 6 can also define a neck 15 adjacent to 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 match 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 to attach to the ischium 9 of the pelvis 3. The second flange 10 is also referred to herein as a "sciatic flange" 10. In other embodiments, such as Figure 1E As shown in , the cage 2 can be formed with an iliac flange 6 but lacking an ischial flange.

[0032] It will be appreciated that the dome 4 may be Figure 1A , and is configured to be seated within the acetabulum 5 and contact the acetabular surface (e.g., the articular (crescent) surface, the acetabular socket, and / or their reamed or otherwise surgically modified portions) as shown in FIG. Figure 1B 1 and 12. The cage 2 is further configured to be placed in an acetabular cup 12 as shown in the drawings, which in turn is in direct contact with the acetabular surface. The cage 2 has sufficient ductility to allow the surgeon to manipulate, bend and shape its portions so as to conform to the shape of the adjacent patient's anatomical structure. Specifically, the ilium flange 6 and the optional ischium flange 10 can be bent and shaped to have a profile that matches the associated profiles of the ilium 7 and ischium 9, respectively. One or more portions of the cage 2 can have geometric features that further promote bending. For example, the neck 15 of the ilium flange 6 is configured to promote bending, twisting and shaping of the ilium flange 6.

[0033] Reference now Figure 1C to Figure 1D, the cage 2 has a first surface or inner surface 14 configured to face the pelvis when implanted and an opposite second surface or outer surface 16 configured to face away from the pelvis 3 when implanted. The cage 2 defines a thickness T measured between corresponding portions of the inner surface 14 and the outer surface 16 in a direction orthogonal to the corresponding portions. The cage thickness T is preferably in the range of about 0.5 mm to about 3.0 mm, and 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 can have a reduced thickness relative to various other portions of the cage 2. In such embodiments, the portions having a reduced thickness can be configured to facilitate bending and shaping along such portions.

[0034] 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 an ischial flange 10. In embodiments lacking an ischial flange, the lower end 20 of the cage 2 may be located at the lowermost edge of the dome 4. The cage 2 also has an anterior side 22 and an opposing posterior side 24. It should be understood that when anatomical directional terms such as "medial", "lateral", "superior", "inferior", "anterior", and "posterior" are used herein with reference to an implant (such as the acetabular cage 2), these anatomical directional terms generally refer to the relative positioning of the implant as the implant is configured to be oriented when implanted.

[0035] The cage 2 includes fixing features for attachment to bone. Figure 1D to Figure 1E As shown in , the dome 4, the iliac flange 6, and the optional ischial flange 10 can each include one or more corresponding fixation holes 26a, 26b for receiving corresponding fixation members (such as bone screws) for attaching the associated portion of the cage 2 to the underlying bone. For example, the iliac flange 6 and / or the optional ischial flange 10 can include one or more flange holes 26a for attaching the corresponding flange 6, 10 to the underlying bone. The one or more flange holes 26a can also have internal threads for locking with complementary threads on the exterior of the head of the locking screw.

[0036] like Figure 1FAs shown in FIG. 1 , one or more flange holes 26a can extend through the respective flanges 6, 10 along a central hole axis 27 oriented to be offset from a transverse axis 29 at an angle A1 that extends orthogonally through the inner and outer surfaces 14, 16 of the cage 2 adjacent the hole 26a. Such holes 26a can be referred to as "angled holes". It should also be appreciated that one or more flange holes 26a (including angled holes and non-angled holes 26a) can have threads or other locking structures for engaging complementary threads on the head of a variable angle (VA) locking screw in a locking manner to provide VA fixation with the variable angle (VA) locking screw. It should be appreciated that including at least one angled 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 customized to provide a target insertion trajectory for an associated bone screw. In this way, the angle A1 can be adapted to customize the insertion trajectory to a specific geometry of a target portion of the bone, which can provide enhanced fixation with 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 customized for the specific geometry of the target portion of the ilium, such as an insertion trajectory that is substantially parallel to the bone material at the target ilium portion. In this way, the angle A1 can be adapted to improve the efficiency of the bone screw biting into the target bone or otherwise engaging the target bone. Another advantage of the angled hole 26a is that the angle A1 can be adapted to reduce the amount of soft tissue disruption (e.g., cutting, resection and / or retraction) adjacent to the hole 26a. For example, the angle A1 of the hole 26a in the iliac flange 6 can be customized to reduce the amount of gluteal muscle resection required to attach the iliac flange 6 to the associated portion of the ilium.

[0037] It should be understood that such VA locking holes 26a in the iliac flange 6 and / or the ischial flange 10 can be constructed as more fully described in U.S. Patent 10,772,665, issued on September 15, 2020 in the name of Bosshard et al. (“the '665 reference”); and U.S. Patent 11,013,541, issued on May 25, 2021 in the name of Bosshard et al. (“the '541 reference”), the entire disclosure of each of which is hereby incorporated by reference herein. Additionally or alternatively, one or more of the holes 26a in the iliac flange 6 and / or the ischial flange 10 can be a VA locking hole 26a having a polygonal hole shape (such as a triangular hole shape) (as viewed in a reference plane orthogonal to the central axis of the corresponding hole). 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 may be constructed as more fully described in U.S. Patent No. 11,179,180, issued on November 23, 2021 in the name of Oberli et al. (“the '180 reference”); and U.S. Patent Publication No. 2021 / 0015526A1, issued on January 21, 2021 in the name of Oberli et al. (“the '526 reference”), the entire disclosure of each of which is hereby incorporated by reference herein. For embodiments of the cage 2 configured for use with the acetabular cup 12, the dome 4 may 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.

[0038] Selected portions of the cage 2 may have gripping features for providing a stronger contact interface with the underlying bone. For example, one or more selected portions of the inner surface 18 may have ridges thereon for pressing into the underlying bone in a manner that enhances fixation. Additionally or alternatively, the cage 2 material along one or more selected portions of the inner surface 18 may be porous, i.e., may have a porous three-dimensional (3D) structure defining a plurality of pores that may be tailored according to various design objectives, such as, by way of non-limiting example, for promoting bone ingrowth into the pores for enhanced postoperative fixation with the underlying bone. The porous structure, including variations of such features, is described in more detail below.

[0039] Implants of the present disclosure, such as the cage 2 of the embodiments illustrated herein, are composed of a titanium alloy, and in particular, of a titanium-aluminum-vanadium alloy: Ti-6Al-4V ("Ti64"). This particular titanium alloy (Ti64) is advantageous for the construction of the implant because Ti64 is stronger and better resistant to fatigue than titanium (including various grades of "commercially pure" titanium (Ti-CP)) and other titanium alloys. However, prior art implants composed of Ti64, such as acetabular cages, are difficult to bend, particularly difficult to bend by physicians during surgery, and particularly in the absence of crack formation at the bending area. The heat treatment processes discussed below have demonstrated the ability to increase the ductility of implants composed of Ti64, such that these cages 2 can be bent, for example, by physicians during surgery without losing structural integrity. In this way, the inventors have discovered a technology that allows the strength and durability of Ti64 to be used in surgical implants (e.g., acetabular cages 2) that are also bendable, representing a significant advance in the field of surgical implants.

[0040] 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 will now be described.

[0041] The geometry of the cage 2 may 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 may be employed to create a physical version of the cage 2 having the geometry and features of the 3D virtual model. The 3D virtual model of the cage 2 may optionally be designed with the aid of patient scan data of the specific anatomical structure to which the cage 2 will be attached. By way of non-limiting example, such patient scan data may include a series of CT scan slices of the acetabulum and adjacent portions of the ilium 7 and ischium 9. Specifically, the iliac flange 6 and optional ischium flange 10 may be customized in the 3D virtual space so that the contours of the flanges 6, 10 correspond to the contours of the corresponding portions of the ilium 7 and ischium 9 to which the flanges will be attached. After the 3D virtual model of the cage 2 is created, a rapid additive manufacturing process may be employed to create the cage 2 having the customized patient-specific 3D virtual geometry.

[0042] The cage 2 can be constructed using a laser-activated PBF process, which can also be referred to as a laser fusion process, which encompasses selective laser sintering (SLS) and selective laser melting (SLM) processes. A non-limiting example of a laser fusion process for constructing the cage 2 will now be described. First, a thin layer of powder is dispensed on a workbench (commonly referred to as a "build platform") so that at least one powder layer forms a powder bed. The powder comprises constituent particles of Ti64 material, which may have various sizes, size distributions, and geometries, and these powder properties may be selected based on parameters that are favorable to the favorable melting of the constructed cage 2 and the melted grain structure. As used herein, the term "build" and its derivatives refer to a structure formed by fusing particles within a powder bed together by a PBF process. Selected areas of the top surface ("build surface") of the powder layer are fused by exposure to a directed energy source (commonly a laser beam). Thus, the exposure pattern of the laser beam forms a cross-section of a three-dimensional object. The cage 2 is constructed by continuous fusion of the cross-sections so formed stacked in a layer-by-layer manner in a vertical direction. Between the fusion of each layer, the build platform is incrementally moved downward and a new layer of powder is deposited onto the build surface. These steps (e.g., lowering the workbench, distributing a new layer of powder on top of the powder bed, and exposing the new layer of powder to the laser source 1) are repeated layer by layer as needed to manufacture the cage 2 as a plurality of successively fused cross-sectional layers. It should be appreciated that the laser fusion process may also be characterized as a 3D printing process. Therefore, the term "build" may be used synonymously with the term "print" herein.

[0043] In the PBF process, the cage 2 can be built in a variety of orientations in the power bed. Two non-limiting examples of such build orientations are FIG. 2A to FIG. 2B As shown in Figure 2A As shown in , cage 2 can be constructed so that outer surface 16 faces downward in the powder bed (and so that inner surface 14 faces upward in the powder bed). Figure 2BAs shown in , the cage 2 can be constructed so that the front side 22 faces downward in the powder bed (and so that the rear side 24 faces upward in the powder bed). At any of these build orientations (and in other build orientations), the cage 2 can be constructed as a base member 30 with raw material below, which can be used as a support structure and subsequently removed during the post-build process. As shown, the cage 2 can be constructed in the powder bed without fixing holes, which can then be formed in the cage 2 during the machining process, such as by a multi-axis computer numerical control (CNC) machine. In other embodiments, the cage 2 can be constructed with fixing holes, which can be further machined and finished in a later machining process. During the PBF process, as shown, the dome 4 can optionally be constructed without a support structure (i.e., raw material) below the dome 4. In other embodiments, the dome 4 can be constructed with a support structure below, which is subsequently removed.

[0044] Preferably, a majority of the cage 2 can be constructed to have a solid structure (e.g., having a 100% packing density). In such embodiments, one or more portions of the cage 2 can have a packing density of less than 100% (such as a packing density in the range of about 50% to about 99.9%), and thus can have a density less than the solid portion. In such one or more portions, a packing density of less than 100% can result from such portions being porous. For example, as described above, such one or more portions of the inner surface 14 of the cage 2 can be porous to promote bone growth into such surface portions of the cage 2. Such porous portions of the cage 2 can be rapidly manufactured according to the techniques and features more fully described in U.S. patent application Ser. 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.

[0045] After the cage 2 is constructed, the cage 2 is subjected to one or more treatment processes, such as one or more heat treatment processes, for modifying the grain structure of the Ti64 implant material as printed in a manner that increases the ductility of the cage 2, particularly for allowing the surgeon to bend portions of the cage 2 during surgery without cracking, breaking, or otherwise causing mechanical failure of such portions. Specifically, the Ti64 grain structure is modified from the as printed metastable martensitic structure to a lamellae α+β phase having a customizable lamellae size to provide the increased ductility disclosed herein. Reference is now made to FIG. 3A to FIG. 3D , shows the resulting grain structure of a Ti64 sample printed and processed according to the embodiments herein. For example, Figure 3A and Figure 3BA magnified view of an exemplary grain structure of a corresponding printed Ti64 alloy sample produced using Ti64 powder having the same properties and subjecting the printed sample to a slightly different custom heat treatment process is shown. As can be seen, Figure 3B The average width of the α-phase flakes α in the Figure 3A The average width of the α-phase flakes α in , indicating that the size of the α-phase flakes α can be tailored (in particular, can be increased), which has been observed to increase ductility. Figure 3C and Figure 3D , the attached enlarged view shows the use of Figure 3B It will be appreciated that the α phase lamellae α have an increased width Wα that is greater than the width of the prior art Ti64 grain structure.

[0046] The processing techniques herein allow the production of nanostructured products having increased size (including increased width Wα) ( Figure 3D )) of the α-phase flakes α, which produces a more ductile material, but at the expense of material strength. It has been observed that cylindrical samples of printed, processed Ti64 produced according to the embodiments herein experienced elongation in the range of 15% to 23% during testing, which is a significant improvement over prior art Ti64. For comparison, Figure 3E The grain structure (including thin sections) of a sample of ISO 20160 alpha+beta titanium alloy is shown. Figure 3E The image shown in is photomicrograph A11 from ISO 20160-2006 taken at 200x magnification.

[0047] The constructed, processed cage 2 may undergo additional processes as desired, such as one or more machining, polishing, roughening and / or coating processes. For example, by way of non-limiting example, one or more additional holes may be formed in the cage 2, such as by drilling, milling, stamping and cutting. It should be appreciated that holes may be formed on the cage in order to improve the bendability of the cage 2 at portions adjacent the holes. Additionally, the constructed, processed cage 2 may undergo additional machining processes, such as wire electrical discharge machining (wire EDM), for contour cutting of the cage 2, including for removing support structures.

[0048] The constructed, processed cage 2 exhibits material properties of superior ductility compared to prior art Ti64 parts of similar thickness. FIG. 4A to FIG. 4B , shows two sets of tensile test results for printed and finished Ti64 tensile bars produced using a custom heat treatment. Figure 4AIn, six (6) samples of printed, processed Ti64 cylinders were subjected to tensile testing at room temperature to measure the following four (4) qualities: (1) Ultimate tensile strength (measured in megapascals (MPa)); (2) Yield strength at 0.2% deflection (also known as 0.2% assurance test) (measured in MPa); (3) Percent elongation after break; and (4) Percent reduction in area. For comparison purposes, the minimum tensile requirements for these four qualities according to ASTM F3001-14. Class A are also listed. Figure 4B In the present invention, three (3) samples of the printed and processed Ti64 cylinders were subjected to similar tensile tests to measure various qualities, including Figure 4A The same four (4) qualities are measured in the test: (1) Ultimate Tensile Strength ("UTS") (measured in MPa); (2) Yield Strength (measured in MPa) at 0.2% deflection ("0.2% Assurance Test"); (3) Percent Elongation after Break (Elongation A%); and (4) Percent Reduction in Area ("Reduction in Area Z%). It should be understood that Figure 4B The sample experience shown in Figure 4A The samples represented in Figure 5 had slightly different heat treatment parameters. FIG. 4A to FIG. 4B The results shown in demonstrate that the printed, processed Ti64 samples measured significantly higher elongations, specifically about 15% to about 23%, with only a modest sacrifice in yield strength and ultimate tensile strength. It should be noted that the elongation of 15% to 23% represents a significant advantage over prior art 3D printed Ti64 constructs.

[0049] Reference now FIG. 5A to FIG. 5C, shows the results of three-point bending tests performed on five different samples of plate-like test specimens: (1) "Ti CP2 Annealed 1.34mm" - annealed commercially pure (CP) grade 2 titanium with a thickness of 1.34mm; (2) "Ti CP2 Stress Relieved 1.34mm" - stress relieved commercially pure (CP) grade 2 titanium with a thickness of 1.34mm; (3) "Ti CP2 Annealed 1.57mm" - annealed commercially 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" - Ti64 alloy heat treated via hot isostatic pressing (HIP) with a thickness of 1.34mm. The test specimens of samples (1) to (5) were rapidly manufactured using a laser fusion PBF process and were approximately 50mm in length and 20mm in width. Using a test apparatus that complies with ASTM E290 requirements, each sample was subjected to a bending displacement target of 8 mm (which would be equivalent to a bending angle of more than 90 degrees), and a graph of displacement versus applied force was plotted. In addition, a bend test was performed by bending the test specimen around a mandrel having a 5 mm diameter.

[0050] like Figure 5A As shown in , sample (4) (Ti64 CHT 1.34mm) was able to bend to the full test displacement (equal to a minimum bend angle of 90 degrees) with a maximum applied force of about 3.25 kN, which is satisfactory for a cage 2 (particularly its flanges) of the same thickness to be bent intraoperatively by a surgeon (such as to conform the shape of the cage 2 to the associated patient anatomy). These results compare favorably with samples of commercially pure titanium, particularly in view of the increased strength of Ti64 relative to commercially pure titanium. As Figure 5B As shown in , three test specimens of sample (4) specimens showed clean bends and had maintained structural integrity (meaning that the specimens showed no signs of any mechanical failure, such as cracking, delamination, or other failure modes). As also demonstrated in these tests, the hot isostatically pressed (HIP) Ti64 sample experienced cracking failure at approximately 3.75 mm displacement (applied force of approximately 2.75 kN), as shown in Figure 5A As shown in Figure 5C These results demonstrate that implants constructed from Ti64 and custom heat treated have superior flexural properties to implants constructed from HIP Ti64.

[0051] Reference now Figure 5D , further bending tests indicated that cage thickness is an important factor for bendability. Figure 5D The results shown in are based on the above reference FIG. 5A to FIG. 5CSimilar three-point bending tests were performed on three different test specimens discussed: (6) “Ti64 CHT 1.34mm” – 1.34mm thick (similar to Figure 5A The results are as follows: (1) "Ti64 CHT 1.64 mm" - a heat treated Ti64 alloy having the same sample parameters as the samples shown in (4); (7) "Ti64 CHT 1.64 mm" - a heat treated Ti64 alloy having a thickness of 1.64 mm; and (8) "Ti CP2 Annealed 1.89 mm" - 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 sample from 1.34 mm to 1.64 mm (an increase of 0.3 mm) may cause failure at approximately 5 mm displacement (and 4.0 kN bending force). 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 the optional ischial flange 10) should be formed to a thickness less than 1.64 mm and preferably closer to 1.5 mm.

[0052] Reference now Figure 6 , further bend testing indicated that implant thicknesses up to about 1.5 mm could be bent to a target test displacement of about 8 mm (equivalent to a bend angle of greater than 90 degrees using a test apparatus conforming to ASTM E290 requirements) without failure. In these bend tests, four (4) sample groups of test specimens having thicknesses of 0.9 mm, 1.1 mm, 1.3 mm, and 1.5 mm, respectively, experienced the same FIG. 5A to FIG. 5D The three-point bend test discussed is similar to the three-point bend test. Figure 6 Each sample set shown in comprises eight (8) test specimens of corresponding thickness.As shown, each of these sample sets was able to achieve the target test displacement (8 mm, 90+ degrees) without failure.

[0053] As mentioned above, the bendable Ti64 acetabular cage 2 disclosed herein provides the strength of Ti64 and other associated benefits while also allowing the surgeon to bend portions of the cage 2 as needed during surgery to correspond to the patient's anatomy. For example, during hip revision surgery, such as surgery for treating 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 the acetabular cup 12, such as by removing soft tissue from the acetabulum and surrounding areas and optionally reaming the acetabulum. With the acetabulum prepared, the surgeon can insert the cup 12 having the cup aperture into the acetabulum in a desired orientation. Subsequently, the surgeon can move the acetabular cage 2 into a position adjacent to the cup 12, particularly by bringing the dome 4 of the cage 2 into contact with or at least in close proximity with 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 this orientation, the surgeon can bend and shape the iliac flange 6 so that the contour of the iliac flange 6 approximates the contour of the portion of the ilium that the iliac flange will contact.

[0054] It should be appreciated that the surgeon need not maintain the cage 2 in contact with or in close proximity to the cup 2 while bending the iliac flange 6 to the desired shape. The surgeon may choose to bring the cage 2 into such a position to visually reference the iliac flange 6 relative to the corresponding portion of the ilium, and then bring the cage 2 into a more comfortable position for performing the bend. This bending and shaping process may also be iterative, whereby the physician may bring the cage 12 into contact with and / or in close proximity to the cup 12 to visually reference the iliac flange 6 relative to the corresponding portion of the ilium, and then may bring the cage 2 into a more comfortable position for performing the bend, and may return the cage 2 to contact with or in close proximity to the cup to further visually reference the iliac flange 6 relative to the corresponding portion of the ilium, and repeat these steps until a satisfactory contour and shape is implanted into the iliac flange 6.

[0055] Additionally, where the selected cage 2 includes an ischial flange 10, the surgeon may bend and shape the ischial flange 10 so that the contour of the ischial flange 10 approximates the contour of the portion of the ischium that the ischial flange will contact. It should be appreciated that the surgeon may shape the ischial flange 10 using steps similar to those used to shape the iliac flange 6 as described above. To attach the cage 2 and cup 12 to the acetabulum, the surgeon may 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 also inserts 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 ilium. If the selected cage 2 includes an ischial flange 10, the surgeon may 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 ischium. Additionally or alternatively, when the selected cage 2 includes an ischial flange 10, the surgeon may insert a portion of the ischial flange 10, and up to the entire ischial flange 10, into the ischium, such as by drilling or otherwise forming a slit or opening in the ischium and inserting the ischial flange 10 into the slit or opening. It should be appreciated that the surgeon may choose to attach some portion of the cage 2 to the underlying bone (such as the dome 4) and form separate portions of the cage 2 (such as the iliac flange 6 and / or the ischial flange 10) to the corresponding bone.

[0056] Reference now Figure 7The trial system 100 for shaping the acetabular cage 2 may include a trial member 52 that is configured to be manipulated, bent, or otherwise shaped in a manner that is substantially conformal to an associated 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 match the contour of the underlying anatomical structure. 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 curved / contoured shape. In this way, the surgeon may employ 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 may be used in its first state to conform to the acetabulum (or the cup 12 disposed in the acetabulum) and adjacent portions of the ilium and optionally the ischium. Specifically, when in its first state, the surgeon may bend the trial member 52 to fit around adjacent portions of the ilium and the acetabulum and around an optional ischium profile to which the cage 2 is desired to be attached. After the trial component 52 has a form-fitting shape, the surgeon may allow the trial component 52 to transition to the second state. After the trial component 52 is in the second state, the surgeon may remove the trial component 52 from the underlying anatomical structure and employ the trial component 52 as a visual reference for bending the corresponding portion of the acetabular cage 2 into the desired shape. As referenced to the trial component 52, after the cage 2 is in the desired shape, the cage 2 may be placed against and attached to the associated anatomical structure (and / or associated cup 12). It should be appreciated that the bending and shaping process of the cage 2 using the trial component 52 may be performed iteratively, whereby the surgeon may bend a portion of the cage 2 based on a visual reference to the associated portion of the trial component 52 and place the bent portion of the cage 2 in contact with or in close proximity to the associated anatomical structure to visually reference the cage 2 shape against the associated anatomical structure, and then move the cage 2 away from the patient's anatomy for further visual reference utilizing the trial component 52 and subsequent bending.

[0057] The trial member 52 can be made of a material that can be activated to transform from a first state to a second state based on a command and within a time period suitable for intraoperative bending and shaping. Preferably, the material used for 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 the first state or the second state include polymer materials, such as polylactic acid (PLA), poly (lactic acid-co-glycolic acid) (PLGA), etc.; and metals, such as 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 (ductile) state by heating the material above its glass transition temperature. When in this first state, the surgeon can bend, shape or otherwise conform the trial member 52 to the corresponding anatomical structure. Thereafter, the material will solidify (i.e., harden) in the formed form, thereby providing a hardened formed trial member 52, which the surgeon can use as a visual and tactile reference when bending and shaping the cage 2. In other embodiments, the material for the test member 52 can be activated to the first state or the second state by applying UV light or other energy. In yet other embodiments, the material for the test member 52 need not be 3D printable, but can be formed by a raw sheet that can be cut, trimmed or otherwise shaped to be similar to the geometry of the cage 2. In other embodiments, the test member 52 can be formed by a raw sheet of PLA, PLGA or similar material, which is placed in a rapid manufacturing (e.g., 3D printing) mold and then molded in the rapid manufacturing mold to a shape that replicates the shape of the cage 2. In some embodiments, the material of the test member 52 can be substantially transparent when in a neutral state and / or a first state. In other embodiments, the raw sheet can be composed of titanium, titanium alloys, stainless steel or other medical grade metals. It should also be understood that the test member 52 does not have to have fixed holes 26a, 26b formed therein. Materials such as PLA and PLGA are good candidates for the constituent materials of the test component 52 because they can be 3D printed into the shape of the cage 2 or 3D printed into a mold for vacuum forming the test component 52, these materials 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 test components 52 can be included together in a kit, wherein each test component 52 can be a single-use test component.

[0058] It should be appreciated that the various parameters of the implant described above and the related techniques for constructing, processing, machining, bending and shaping these implants are provided as exemplary features for adapting the implant to be substantially conformable to the patient's anatomical structure. These parameters may be adjusted as desired without departing from the scope of the present disclosure.

[0059] It should be further understood that when a numerical preposition (e.g., "first," "second," "third") is used herein with reference to an element, component, dimension, or feature thereof (e.g., a "first" flange, a "second" flange, a "second" state, a "first" state), such numerical preposition is used to distinguish the element, component, dimension, and / or feature from another such element, component, dimension, and / or feature and is not limited to the specific numerical preposition used in that context. For example, a "first" member may also be referred to as a "second" member in different contexts without departing from the scope of the present disclosure, as long as the element, component, dimension, and / or feature remains appropriately distinguished in the context in which the numerical preposition is used.

[0060] Although the present disclosure has been described in detail, it should be understood that various changes, substitutions and modifications may be made herein without departing from the spirit and scope of the present invention as defined by the appended claims. In addition, the scope of the present disclosure is not intended to be limited to the specific embodiments described in this specification. Specifically, one or more of the features from the features of the aforementioned embodiments may be used in other embodiments herein. It will be readily understood by those of ordinary skill in the art that existing or later developed processes, machines, manufactures, material compositions, devices, methods or steps that perform substantially the same functions as the corresponding embodiments described herein or achieve substantially the same results may be utilized according to the present disclosure.

Claims

1. An implantable device comprising: A portion, wherein at least a majority of the portion as measured by volume comprises a Ti64 alloy, wherein the portion is 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 claim 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 claim 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. The implantable device of claim 1, wherein the portion is composed 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 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-fused particles of a Ti64 alloy having an α+β phase lamellar grain structure.

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

9. The acetabular cage of claim 8, wherein the 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 of claim 8, wherein the cage is comprised of laser fused particles of Ti64 alloy.

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

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

13. A method of preparing an implant for implantation, the method comprising: A portion of the implant is bent about a bending axis to a bend angle of at least about 50 degrees, wherein at least a majority of the portion as measured by volume comprises a Ti64 alloy, and the portion maintains structural integrity during and after the bending step.

14. The method of claim 13, wherein the bending step comprises bending the portion about the bending axis to a bend angle of at least about 90 degrees.

15. The method of claim 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.

16. The method according to claim 13, further comprising: One or more additional portions of the implant are bent so as to have a shape that is substantially conformable to the patient's anatomy, wherein the one or more additional portions of the implant are substantially composed of Ti64.

17. The method according to claim 16, further comprising: Prior to the bending step and the further bending step, the trial implant is shaped to conform to the patient anatomy.

18. The method according to claim 17, further comprising: Prior to the shaping step, the trial implant is transformed from a neutral state to an extensible state, wherein the shaping step is performed while the trial implant is in the extensible state.

19. The method according to claim 18, further comprising: After the shaping step, the trial implant is transformed from the ductile state to a generally rigid state in which the trial implant substantially retains its shape.

20. The method according to claim 19, further comprising: The shape of the trial implant is visually referenced while performing the bending step and the further bending step, wherein the bending step and the further bending step are performed to make the implant approximate the shape of the trial implant.

Images