Patent Description:
The embodiments disclosed herein are generally directed towards three-dimensional porous structures for bone ingrowth and methods for producing said structures.

The field of rapid prototyping and additive manufacturing has seen many advances over the years, particularly for rapid prototyping of articles such as prototype parts and mold dies. These advances have reduced fabrication cost and time, while increasing accuracy of the finished product, versus conventional machining processes, such as those where materials (e.g., metal) start as a block of material, and are consequently machined down to the finished product.

Examples of modern rapid prototyping/additive manufacturing techniques include sheet lamination, adhesion bonding, laser sintering (or selective laser sintering), laser melting (or selective laser sintering), photopolymerization, droplet deposition, stereolithography, 3D printing, fused deposition modeling, and 3D plotting. Particularly in the areas of selective laser sintering, selective laser melting and 3D printing, the improvement in the production of high density parts has made those techniques useful in designing and accurately producing articles such as highly dense metal parts.

The additive manufacturing field has created orthopaedic prosthetic components that promote mammalian cell growth and regeneration. Current methods and geometries can control the pore size distribution, which exerts a strong influence on the ingrowth behavior of mammalian cells such as bone, and further produce porous structures having unit cell geometries with pore sizes and porosities simultaneously in the range believed to be beneficial for ingrowth while maintaining structural integrity during the manufacturing process (e.g., 3D printing).

<CIT> provides for the formation of molds for use in casting bone prostheses. The mold is printed and loose powder material which is not solidified or bonded within the casting mold is removed from about the casting mold. The mold may be shaken to dislodge and remove loose powder, or it may be immersed in a bath or solvent in which the loose powder material is washed away or dissolved while the solidified portions of the mold remain. Loose powder material which is difficult to remove completely because of its location within the casting mold may be more readily removed by subjecting the casting mold to ultrasonic or other high frequency vibration, followed by or concurrently with immersion in a bath or solvent.

The invention concerns a method for removing at least one particle from an additively manufactured orthopaedic prosthetic component as defined in claim <NUM>. The method includes the step of submerging at least a portion of the additively manufactured orthopaedic prosthetic component in a liquid. The method further includes the step of sonicating at least a portion of the additively manufactured orthopaedic prosthetic component so as to loosen the at least one particle. The method further includes the step of shaking the additively manufactured orthopaedic prosthetic component so as to evacuate the at least one particle from the additively manufactured orthopaedic prosthetic component.

In one aspect, the loosened at least one particle is detached from the orthopaedic prosthetic component but disposed in the orthopaedic prosthetic component. The shaking step may be performed while the at least one particle is submerged in the liquid. The sonicating step occurs at a sonication frequency, and shaking step occurs at a shaking frequency that is less than the sonication frequency. The liquid is polar in one embodiment. In another embodiment, the liquid is nonpolar or substantially nonpolar. In one aspect, the method can include the step of increasing a density of the liquid. In one aspect, the method can include the step of adding a salt to the liquid to increase the density. In another aspect, the method further includes the step of adding a dispersion agent to the liquid.

In one embodiment, the method includes the step of filtering the at least one particle from the fluid. The filtering step causes the liquid to flow through the filtration substrate, and prevents the at least one particle to flow through the filtration substrate during the causing step. The weight of the at least one particle is determined.

In another embodiment, a method is provided for evaluating an orthopaedic prosthetic component. The method for evaluating the orthopaedic prosthetic component can be performed individually, or in combination with any of the steps associated with the method for removing the at least one particle from the orthopaedic prosthetic component. The orthopaedic prosthetic component includes an additively manufactured structure having a at least one residual particle. The another embodiment or the embodiment method can include the step of obtaining a magnified image of at least a portion of a substrate and at least one particle supported by the substrate, such as the evacuated at least one particle supported by the substrate. The magnified image may be viewed on a display. The at least one particle may be surrounded by at least one boundary line on the image along a respective outer perimeter of the at least one particle. The method may further includes the step of determining at least one of <NUM>) a quantity of the at least one particle and/or a quantity of groups of the at least one particle, <NUM>) a size of the at least one particle, <NUM>) an aspect ratio of the at least one particle, and <NUM>) a weight of the at least one particle. In some embodiments, the method further includes the step of removing the at least one particle from the orthopaedic prosthetic component.

The method can further include the step of placing the substrate under a microscope so as to generate the magnified image.

In one aspect, the method further includes the step of thresholding the image so as to define the at least one boundary line, potentially wherein an area defined by the boundary represents at least one particle.

In one aspect, the at least one particle comprises a plurality of groups of particles spaced from each other in their respective entireties, and the method further includes the step of identifying a region of interest on the substrate that surrounds all of the particles prior to the surrounding step. The substrate can comprise a filter paper or any other substrate suitable for supporting the particles. In another aspect, the method further includes the step of thresholding the region of interest so as to surround the plurality of particles with respective boundary lines.

In one aspect, the method includes the step of scanning each at least one particle inside each respective at least one boundary line to determine a characteristic of the at least one particle, the at least one characteristic including at least one of <NUM>) a quantity of the at least one particle and/or the quantity of groups of the at least one particle, <NUM>) a size of the at least one particle, and <NUM>) an aspect ratio of the at least one particle. The method can include the step of comparing the determined characteristic against a predetermined threshold. In one aspect, the method further includes the step of providing illumination to the region of interest prior to the thresholding step. The illumination of the particles on the substrate can be adjusted to within a predetermined illumination range. The method may further comprise the step of placing the substrate under a microscope so as to generate the magnified image. The at least one particle may have been evacuated from an orthopaedic prosthetic component or from a plurality of orthopaedic prosthetic components.

A still further embodiment may provide a method for evaluating an orthopaedic prosthetic component, the method comprising the steps of: obtaining a magnified image of at least a portion of a substrate and at least one particle supported by the substrate, wherein the at least one particle has been removed from the an additively manufactured structure of the orthopaedic prosthetic component; viewing the magnified image on a display; surrounding the at least one particle with at least one boundary line on the image along a respective outer perimeter of the at least one particle, respectively; and determining at least one of <NUM>) a quantity of groups of the at least one particle, <NUM>) a size of the at least one particle, <NUM>) an aspect ratio of the at least one particle, and <NUM>) a weight of the at least one particle. The embodiment may further comprise the step of thresholding the image so as to define the at least one boundary line, wherein the boundary line surrounds an area that represents the particle, the method comprising the step of scanning the area so as to determine at least one of <NUM>) a quantity of groups of the at least one particle, <NUM>) the size of the at least one particle, and <NUM>) the aspect ratio of the at least one particle.

While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications and alternatives falling within the scope of the invention as defined by the appended claims. Further, the term "at least one" stated structure as used herein can refer to either or both of a single one of the stated structure and a plurality of the stated structure. Additionally, reference herein to a singular "a," "an," or "the" applies with equal force and effect to a plurality unless otherwise indicated. Similarly, reference to a plurality herein applies with equal force and effect to the singular "a," "an," or "the.

References in the specification to "one embodiment", "an embodiment", "an example embodiment", etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic.

Further, references in the specification to "about," "approximately," "substantially," derivatives thereof, and words of similar import, when used to describe one or more parameters including sizes, shapes, spatial relationships, distances, directions, and other similar parameters includes the stated parameter in addition to a range up to <NUM>% more and up to <NUM>% less than the stated parameter, including <NUM>% more and <NUM>% less, including <NUM>% more and <NUM>% less, including <NUM>% more and <NUM>% less.

The present disclosure relates to the additive manufacture of porous three-dimensional metallic structures for orthopaedic prosthetic components, and methods for analyzing the manufacture of such structures. The porous metallic structures promote hard or soft tissue interlocks between prosthetic components implanted in a patient's body and the patient's surrounding hard or soft tissue. For example, when included on an orthopaedic prosthetic component configured to be implanted in a patient's body, the porous three-dimensional metallic structure can be used to provide a porous outer layer of the orthopaedic prosthetic component to form a bone in-growth structure. Alternatively, the porous three-dimensional metallic structure can be used as an implant with the required structural integrity to both fulfill the intended function of the implant and to provide interconnected porosity for tissue interlock (e.g., bone in-growth) with the surrounding tissue. In various embodiments, the types of metals that can be used to form the porous three-dimensional metallic structures can include, but are not limited to, titanium, titanium alloys, stainless steel, cobalt chrome alloys, tantalum or niobium.

Referring now to <FIG>, an implantable apparatus such as an orthopaedic implant or prosthetic component <NUM> is illustrated. The prosthetic component <NUM> includes a base <NUM>, a porous three-dimensional structure or layer <NUM>, and a cone or stem <NUM> extending away from the base <NUM>. In the illustrative embodiment, the porous structure <NUM> surrounds a portion of the base <NUM> and a portion of the stem <NUM>. It should be appreciated that the porous structure <NUM> can be provided as a layer separate from the base <NUM> and/or the stem <NUM>. The porous structure <NUM> may also provide the entire structure of the prosthetic component <NUM> or as a coating that surrounds some or all of the base <NUM> and/or all of the stem <NUM>. As described in greater detail below, the porous structure includes a plurality of unit cells that define voids or spaces that permit the ingrowth of bone, thereby promoting fixation of the prosthetic component <NUM> to a patient's bone.

The orthopaedic implant <NUM> may be implanted into a tibial bone. For example, the stem <NUM> can be inserted into the tibial bone, with a ledge portion <NUM> of implant <NUM> resting against a proximal portion of the tibial bone. It should be appreciated that the various porous structures described herein may be incorporated into various orthopaedic implant designs, including, for example, a tibial prosthetic component or a femoral prosthetic component similar to the tibial and femoral components shown in <CIT>. The porous structures may also be included in other orthopaedic implant designs, including a patella component shaped to engage a femoral prosthetic component and prosthetic components for use in a hip or shoulder arthroplasty surgery.

It should also be noted, for the preceding and going forward, that the base <NUM> can be any type of structure capable of, for example, contacting, supporting, connecting to or with, or anchoring to or with components of various embodiments herein. The base <NUM> can include, for example, a metal or non-metal tray, a metal or non-metal baseplate, a metal or non-metal structure that sits on a tray, and so on. The types of metal that can be used to form the base <NUM> include, but are not limited to, titanium, titanium alloys, stainless steel, cobalt chrome alloys, tantalum or niobium.

In the illustrative embodiment, the stem <NUM> includes a solid region <NUM>, which is coated by a porous region <NUM> of the porous structure <NUM>. The solid region <NUM> of the stem <NUM> is anchored to the base <NUM> and extends outwardly from the porous structure <NUM> such that the porous structure <NUM> surrounds the region of stem <NUM> proximal to base <NUM>. In other embodiments, the stem <NUM> may be anchored to the porous structure <NUM>. The types of metal that can be used to form the stem <NUM> include, but are not limited to, titanium, titanium alloys, stainless steel, cobalt chrome alloys, tantalum or niobium.

Referring now to <FIG>, the porous structure <NUM> of the implant <NUM> can comprise a plurality of connected unit cells. Each unit cell defines a unit cell structure <NUM> that includes a plurality of lattice struts <NUM> so as to define a first geometric structure <NUM>. Each unit cell further defines a plurality of internal struts <NUM> that are disposed within the first geometric structure <NUM> so as to define a plurality of second geometric structures <NUM>. In one example, the first geometric structure <NUM> can include the plurality of lattice struts <NUM>. The lattice struts <NUM> cooperate to define the first geometry. Each second geometric structure <NUM> can be formed by a plurality of the internal struts <NUM> and a plurality of the lattice struts <NUM>. Each of the plurality of second geometric structures <NUM> can define an internal volume that is substantially equal to the internal volumes of the other second geometric structures <NUM>. In one example, the first geometric structure can be a rhombic dodecahedron, and the second geometric structure can be a rhombic trigonal trapezohedron. It should be appreciated, of course, that the first and second geometric structures can vary as desired. Further, it should be appreciated that the unit cells that make up the casing <NUM> can have any suitable alternative geometry as desired. For instance, in alternative embodiments, the unit cells can be defined by the plurality of lattice struts <NUM> without internal struts <NUM>. In other alternative embodiments, the unit cells can be defined by lattice struts <NUM> and internal struts <NUM> that define any suitable geometry, respectively, as desired. Examples of such alternative geometries are described in <CIT>.

Referring now to <FIG>, the porous three-dimensional structure <NUM> can be fabricated using any suitable additive manufacturing process as desired, including any of the additive manufacturing processes described below. It is recognized that structures created using additive manufacturing processes can include residual particles as artifacts of the additive printing process. For instance, some additive manufacturing processes involve the deposition of a layer of powder onto a base, and fusing the layer of powder to the base. Subsequent layers of powder are deposited onto the respective preceding layers and subsequently fused to the previous layer to form the porous three-dimensional metallic structures. It is recognized that the manufactured porous three-dimensional structure <NUM> can include quantities of particles <NUM> that are to be removed prior to use. For instance, the completed part can include residual particles in the form of powder or other particulates. The residual powder can be the product of the additive manufacturing process, and can thus include, but are not limited to, titanium, titanium alloys, stainless steel, cobalt chrome alloys, tantalum or niobium. Alternatively or additionally, the particles can be soil or other debris that may reside on or in the manufactured structure <NUM>.

In order to prevent the orthopaedic prosthetic component <NUM> from being implanted in a mammalian body while containing these particles <NUM> that can subsequently become dislodged, it is desirable to remove the particles <NUM> from the component after the component has been manufactured and prior to implantation. It can be further desirable to analyze the removed particles for quality control purposes, and to ensure that the nature and quantity of the removed particles did not potentially compromise the structural integrity of the additively manufactured porous three-dimensional component.

Referring to <FIG> and <FIG>, a method <NUM> is provided for removing the residual particles <NUM> from the porous three-dimensional structure <NUM> for subsequent analysis. The method <NUM> can include the first step <NUM> of cleaning the prosthetic orthopaedic component <NUM> so as to remove the particles <NUM> from the component <NUM>. In some circumstances, the particles <NUM> can be adhered, bonded, or otherwise attached to the component <NUM> after the porous three-dimensional structure <NUM> has been manufactured. For instance, the particles <NUM> can be adhered, bonded, or otherwise attached to the base <NUM> and/or the stem <NUM>. Alternatively or additionally, the particles <NUM> can be adhered, bonded, or otherwise attached to the porous three-dimensional structure <NUM>.

The cleaning step <NUM> is configured to remove the particles <NUM> from the component <NUM>. In particular, referring to <FIG>, at least a portion of the orthopaedic prosthetic component <NUM> is submerged in a solvent <NUM> that is disposed in any suitable container <NUM>, such as a beaker or other suitable pourable container. The solvent <NUM> can be any suitable fluid such as a liquid. In some examples, the liquid can be nonpolar. For instance, the liquid can be water, such as deionized water in some embodiments. Alternatively, the liquid can be substantially polar. For instance, the liquid can be acetone or an alcohol, such as isopropyl alcohol (IPA). Alternatively, the liquid can be oil based. Thus, liquids of different viscosities can be provided. Liquids having high viscosities can increase the transportability of the particles <NUM> in the solvent <NUM>. The orthopaedic prosthetic component <NUM> is placed in the container <NUM> such that at least the porous three-dimensional structure <NUM> is submerged in the solvent <NUM>. In some embodiments, an entirety of the orthopaedic prosthetic component <NUM> can be submerged in the solvent <NUM>.

In some embodiments, it is desirable to remove the particles <NUM> from the component <NUM> so that the particles can be easily removed from the container <NUM>. Thus, one or more agents can be added to the solvent <NUM> as desired. For instance, a densifier can be added to the solvent <NUM> that increases the density of the solvent. In one example, the densifier is salt. Increasing the density of the solvent <NUM> increases the buoyancy of the particles <NUM> and reduces the tendency for the particles <NUM> to accumulate on the bottom of the container <NUM>. Further, increasing the density of the solvent <NUM> can increase the transportability of the particles <NUM> in the solvent <NUM>. In some embodiments, it is desirable to prevent or reduce aggregation of the particles <NUM> in the fluid. Thus, any suitable dispersion agent such as a detergent can be added to the solvent <NUM> as desired. The dispersing agent increases the dispersion of the particles <NUM> in the solvent <NUM>. Any one or more of these additives can be included in the solvent <NUM> as desired.

In some embodiments, for instance when it is desirable to analyze the particles <NUM> of a single orthopaedic prosthetic component <NUM>, the single orthopaedic prosthetic component <NUM> is placed in the container <NUM>. In other embodiments, a plurality of orthopaedic prosthetic components <NUM> can be placed in the container <NUM>. This embodiment can be particularly suitable when it is desired to efficiently analyze the particles <NUM> of a plurality of orthopaedic prosthetic components <NUM>. This embodiment can also be particularly suitable when it is desired to remove, but not analyze, the particles <NUM> from a plurality of orthopaedic prosthetic components <NUM>.

Next, referring to <FIG>, the cleaning step <NUM> includes the step <NUM> of loosening the attached particles <NUM> from the prosthetic orthopaedic component <NUM>. In one embodiment, the porous orthopaedic component <NUM> is sonicated to loosen the attached particles <NUM> from the prosthetic orthopaedic component <NUM>. In particular, a sonicator <NUM> may be used to subject the component <NUM> to high frequency vibration In the illustrative embodiment, the sonicator <NUM> is activated to deliver high frequency vibration to the porous orthopaedic component <NUM>. The sonicator <NUM> can be of the type that includes a sonication tank that contains a sonication liquid <NUM> configured to deliver the high frequency vibration to the container <NUM>. In some examples the high frequency vibration is delivered to the container <NUM> at an ultrasonic frequency. The sonication liquid can be water, such as reverse osmosis (RO) water.

The container <NUM> is placed in the in the sonicator <NUM> such that the container <NUM> is disposed in the sonication liquid <NUM> at a position that prevents the sonication liquid <NUM> from entering the container <NUM> during use. The sonicator <NUM> is activated to deliver high frequency vibration to the container <NUM> at any suitable sonication frequency for any suitable duration at any suitable temperature. The temperature can be any suitable temperature as desired. In one example, the temperature can be between about <NUM> degrees F to approximately <NUM> degrees F. For instance, the temperature can be room temperature, such as approximately <NUM> degrees F. The sonication frequency can be within a range from approximately <NUM> to approximately <NUM>, or any suitable frequency as desired. In one example, the range of sonication frequencies can be from approximately <NUM> to approximately <NUM>. During operation, the sonicator <NUM> delivers the high frequency vibration to the sonication liquid <NUM> which, in turn, delivers the high frequency vibration to the container <NUM> and solvent <NUM>. In particular, the sonication frequency causes cavitation in the solvent <NUM>, which drives the solvent to create forces onto the residual particles that cause the particles to loosen from the prosthetic orthopaedic component <NUM>.

Further, the sonication process can include delivering high frequency vibrations to the container at a plurality of sonication frequencies. For instance, the sonicator <NUM> can deliver a first high frequency vibration to the container <NUM> at a first sonication frequency. Next, the sonicator <NUM> can then deliver a second high frequency vibration to the container <NUM> at a second sonication frequency. The second sonication frequency can be greater than the first sonication frequency. Next, the sonicator <NUM> can then deliver a third high frequency vibration to the container <NUM> at a third sonication frequency. The third sonication frequency can be greater than the second sonication frequency. In one example, the first sonication frequency is one of approximately <NUM> and <NUM>. The second sonication frequency is approximately <NUM>. The third sonication frequency is approximately <NUM>. The first, second, and third sonication frequencies can be delivered for any suitable time duration as desired. In one example, the time direction can be approximately <NUM> minutes, though longer or shorter time durations are also envisioned. It is recognized that lower sonication frequencies are more suitable to loosen large particles, and higher sonication frequencies are more suitable to loosen small particles.

Because the orthopaedic prosthetic component <NUM> is disposed in the container <NUM> during the sonication process, the residual particles <NUM> can be easily retrieved from the container <NUM> if desired. Alternatively, it should be appreciated that the orthopaedic prosthetic component <NUM> can be placed directly into the sonication liquid <NUM>, and disposed in the sonication liquid <NUM> during the sonication process.

Referring now to <FIG>, and as described above, the sonication has caused residual particles <NUM> that were attached to the prosthetic orthopaedic component <NUM> to become detached and loosened from the prosthetic orthopaedic component <NUM>. Further, it is recognized that in some examples at least some of the particles <NUM> can be free from attachment to the prosthetic orthopaedic component <NUM>, but lodged in the component <NUM>, prior to the cleaning step <NUM>. It is appreciated, however, that at least some of the loosened particles <NUM> may not be evacuated from the orthopaedic prosthetic component <NUM>. For instance, the loosened particles <NUM> may be trapped in the orthopaedic prosthetic component. In one example, the internal struts <NUM> and lattice struts <NUM> can prevent the loosened particles <NUM> from traveling out of the prosthetic orthopaedic component <NUM>, and in particular out of the porous three-dimensional structure <NUM>.

Accordingly, referring now to <FIG> and <FIG>, the cleaning step <NUM> can include a step <NUM> of evacuating the particle <NUM> from the orthopaedic prosthetic component <NUM>. The loosened particles <NUM> may have become loosened during the sonicating step. Alternatively, as noted above, some or all the particles <NUM> may have been loose from the orthopaedic prosthetic component prior to sonicating. The evacuating step can include the step of shaking the container <NUM> in order to cause the loose particles <NUM> to flow out from the prosthetic orthopaedic component <NUM> in the solvent <NUM>.

The shaking step can include the step of attaching the container <NUM> to a support member <NUM> of a shaker apparatus <NUM>. In one embodiment, the container <NUM> can be placed in the support member <NUM>, such that the support member <NUM> firmly supports the container <NUM>. Thus, as the support member <NUM> causes the container <NUM> to shake, the support member <NUM> prevents unintended movement of the container <NUM> during the shaking step. Thus, the shaking step can transport the particles away from the prosthetic orthopaedic component <NUM>. During operation, the shaker apparatus <NUM> causes the support member <NUM> to shake the container <NUM>. Shaking of the container <NUM> causes the solvent <NUM> to flow inside the container <NUM>, which drives the particles <NUM> to evacuate the prosthetic orthopaedic component <NUM>. The shaking step can be performed for any duration of time as desired, such as approximately ten minutes in one example. After the shaking step has been completed, the loosened particles <NUM> that have been evacuated from the prosthetic orthopaedic component <NUM> are suspended in the solvent <NUM> in one embodiment. In other embodiments, at least some of the loosened particles <NUM> can be disposed on the base of the container <NUM>, and subsequently removed from the container <NUM>. The shaking step can cause the container <NUM> to undergo repeated physical reciprocal motion at a shaking frequency of between approximately <NUM> and approximately <NUM> reciprocal (e.g., back and forth) movements per minute, such as between approximately <NUM> and <NUM> reciprocal movements per minutes, for instance approximately <NUM> reciprocal movements per minute. Thus, the shaking frequency is less than the sonication frequency. It is appreciated that the shaking frequency can be adjusted depending on many factors, such as the geometry of the orthopaedic prosthetic component <NUM> and various characteristics of the particles. During operation, the shaking frequency causes a gentle cavitation in the solvent <NUM>, which creates a flow exchange between the solvent <NUM> within the orthopaedic prosthetic component <NUM> and the solvent that surrounds the orthopaedic prosthetic component <NUM>. The solvent <NUM> within the orthopaedic prosthetic component <NUM> can contain one or more residual particles <NUM> that have loosened from the orthopaedic prosthetic component <NUM> during the sonication step. The flow exchange causes the solvent <NUM> within the orthopaedic prosthetic component <NUM>, and thus the loosened particles <NUM> disposed in the solvent <NUM>, to be transported out of the prosthetic orthopaedic component <NUM>.

In this regard, the sonication step can be referred to as a high frequency vibration of the prosthetic orthopaedic component which can be defined by the sonication frequency as described above, and the shaking step can be referred to as a low frequency vibration of the prosthetic orthopaedic component which can be defined by the shaking frequency as described above. The low frequency of vibration is less than the high frequency vibration. For instance, the high frequency vibration can be greater than <NUM> times the low frequency vibration, for instance greater <NUM> times the low frequency vibration. Thus, the method can include the step of subjecting at least a portion of the prosthetic orthopaedic component <NUM> up to an entirety of the prosthetic orthopaedic component to the high frequency of vibration so as to loosen at least one of the attached particles <NUM> from the prosthetic orthopaedic component <NUM>, and subsequently subjecting the at least a portion of the prosthetic orthopaedic component <NUM> up to an entirety of the prosthetic orthopaedic component to the low frequency of vibration so as to evacuate the loosen at least one of the attached particles <NUM> from the orthopaedic prosthetic component <NUM>.

Referring again to <FIG>, while the cleaning step <NUM> can include the sonicating and shaking steps <NUM> and <NUM> in one examples, other methods are contemplated for loosening and evacuating the particles <NUM> from the prosthetic orthopaedic component <NUM>. For instance, a stream of liquid or other vacuum mechanism can be directed at the prosthetic orthopaedic component <NUM> at a force and for a duration sufficient to loosen and evacuate the particles <NUM> from the prosthetic orthopaedic component <NUM>. The stream of liquid or vacuum can replace either or both of the sonicating and shaking steps. Of course, it can be desirable to place a container at a location that receives the particles <NUM> that are removed in response to the stream of liquid. Once the particles <NUM> have been collected in a suitable container, the method <NUM> can proceed to step <NUM> of filtering the particles <NUM> from the solvent <NUM>.

Referring now to <FIG> and <FIG>, a filtration assembly <NUM> is configured to filter the removed particles <NUM> from the solvent <NUM>. In particular, the solvent <NUM> can be driven through a filtration substrate <NUM>, such that the particles <NUM> accumulate on the substrate <NUM>. The substrate <NUM> is thus porous with respect to the solvent <NUM>, but nonporous with respect to the particles <NUM>. Further, the filtration assembly <NUM> can include an air pressure source in the form of an air pump <NUM> that delivers air pressure to the solvent <NUM> that drives the solvent through the substrate <NUM>. In one embodiment, the air pressure source <NUM> is a vacuum that delivers negative pressure to the solvent <NUM>, thereby drawing the solvent <NUM> through the substrate <NUM> as the solvent is delivered to the substrate <NUM>. Alternatively, the air pressure source can be a positive air pump that forces the solvent <NUM> through the substrate <NUM> as the solvent is delivered to the substrate <NUM>.

Prior to the filtration step, the filtration substrate <NUM> is weighed. As will be described in more detail below, knowing the weight of the filtration substrate <NUM> provides for a more accurate subsequent determination of the weight of the particles <NUM>. The filtration assembly <NUM> further includes a porous support member <NUM> that is configured to support the filtration substrate <NUM>. In particular, the filtration substrate <NUM> is placed on top of the porous support member <NUM>. The filtration substrate <NUM> can further be fastened, such as clamped, to the porous support member <NUM>. The porous support member <NUM> is porous to air and the solvent <NUM>, such that the solvent that is drawn through the filtration substrate <NUM> is also drawn through the porous support member <NUM>. In one example, the porous support member <NUM> can be a screen or mesh. The filtration substrate <NUM> can be configured as filter paper.

The porous support member <NUM> can be in fluid communication with a first container <NUM> that is configured to receive the solvent <NUM> that passes through the porous support member <NUM>. For instance, the porous support member <NUM> can be supported directly or indirectly by the first container <NUM>. Further, in one embodiment the filtration assembly <NUM> includes an inlet <NUM> that is configured to receive the solvent <NUM> and particles <NUM>, and directs the solvent <NUM> to travel through the porous support member <NUM> and into the first container <NUM>. The filtration assembly <NUM> can further include a trap container <NUM> that is in fluid communication with the first container <NUM>. In particular, the filtration assembly <NUM> includes a drain and a first conduit <NUM> that extends from the drain of the first container <NUM> to an inlet of the trap container <NUM>. When the level of liquid in the first container <NUM> rises to the level of the drain, the liquid in the first container <NUM> travels along the conduit <NUM> from the first container <NUM> to the trap container <NUM>. The inlet of the trap container <NUM> can be disposed below the outlet of the first container <NUM>.

The filtration assembly <NUM> further includes an air pump <NUM> that is in fluid communication with the trap container <NUM>. For instance, the filtration assembly <NUM> can include a second conduit <NUM> that extends from the trap container <NUM> to the air pump <NUM>. The filtration assembly <NUM> can further include a trap filter <NUM> disposed in the second conduit <NUM> that allows air to pass through, but is nonporous with respect to the solvent <NUM> and water.

During operation, the solvent <NUM> and particles <NUM> contained therein are delivered to the inlet <NUM>. The inlet can be configured as a funnel or any suitable container with an open end that receives the liquid and particles <NUM> disposed in the liquid. Thus, the solvent <NUM> can be poured from the container <NUM> (see <FIG>) into the inlet, such that the solvent <NUM> and the particles <NUM> are delivered to filtration substrate <NUM>. If desired, an additional quantity of liquid, sch as deionized water, can be sprayed or squirted against the interior walls of the container <NUM> and emptied into the inlet <NUM>. Thus, particles <NUM> that might have still remained on a wall of the container <NUM> is delivered into the funnel. Because the filtration substrate <NUM> is not sufficiently porous to allow the particles <NUM> to pass through, the particles <NUM> amass on an outer surface of the filtration substrate <NUM> as the liquid flows through the filtration substrate <NUM>.

The air pump <NUM> is activated so as to induce a negative pressure that drives the solvent <NUM> and any additional liquid disposed in the inlet <NUM> (collectively referred to as liquid) through the filtration substrate <NUM>. In particular, the negative pressure induced by the pump <NUM> is in fluid communication with the filtration substrate <NUM> through the first container <NUM>, the first conduit <NUM>, the trap container <NUM>, and the second conduit <NUM>. The particles <NUM> remain on the filtration substrate <NUM> as the liquid flows through the filtration substrate <NUM>. The liquid flows from the filtration substrate <NUM> through the porous support member <NUM>, and into the first container <NUM>. If the liquid rises in the first container <NUM> to a level equal to the drain of the first container <NUM>, the liquid travels through the conduit <NUM> into the trap container <NUM>, thereby maintaining a negative pressure differential across the filtration substrate <NUM> as induced by the air pump <NUM>. Once the liquid has been drained from the inlet <NUM>, additional liquid such as deionized water can be sprayed or squirted to the walls of the funnel in order to ensure that particles <NUM> that remain on the funnel walls are delivered to the filtration substrate <NUM>. The air pump <NUM> can be deactivated once substantially all liquid has been removed from the funnel.

Next, referring again to <FIG>, it is recognized that the particles <NUM> and the filtration substrate <NUM> are wet after completion of the filtering step <NUM>. Therefore, the particles <NUM> are dried at step <NUM>. In particular, as illustrated in <FIG>, the filtration substrate <NUM> is removed from the filtration assembly and placed into an oven <NUM> that can heat the filtration substrate <NUM> to a temperature for a duration of time that is suitable to dry the substrate <NUM> and the particles <NUM> disposed on the substrate. In particular, the filtration substrate <NUM> is removed from the filtration assembly <NUM> and placed on an optical support member <NUM>. In one embodiment, the support member <NUM> is configured as an optically transparent support member <NUM>. For instance, as shown on <FIG>, the optically transparent support member <NUM> can be a glass slide. As will be described in more detail below, the glass slide <NUM> is optically transparent that is suitable to allow the particles <NUM> to be examined under a microscope. The glass slide <NUM> supports a bottom surface of the filtration substrate <NUM>, while the particles <NUM> are disposed on a top surface of the filtration substrate <NUM> that is opposite the bottom surface.

Referring again to <FIG>, the oven <NUM> is heated to any temperature suitable for drying the liquid from the filtration substrate <NUM>. For instance, the oven can be heated to any temperature that ranges from approximately <NUM> degrees F to approximately <NUM> degrees F. It can be desirable to heat the oven to a low temperature setting for the purposes of drying the liquid from the filtration substrate <NUM>, particularly when the liquid is water. Accordingly, in one example, the oven can be set to a range from approximately <NUM> degrees F to approximately <NUM> degrees F, such as approximately <NUM> degrees F. Once the oven <NUM> has reached the desired temperature, the glass slide <NUM> and filtration substrate <NUM> are placed into the oven <NUM> for a duration suitable to allow the liquid to dry. For instance, the duration of time can be approximately ten minutes or until the filtration substrate <NUM> and particles <NUM> have dried.

Next, referring to <FIG>, the drying step <NUM> can further include the step of desiccating the filtration substrate <NUM> and the particles <NUM>. In particular, the glass slide <NUM> is removed from the oven <NUM> and placed in a desiccator <NUM> to remove remaining moisture from the filtration substrate <NUM> and particles <NUM>. The temperature of the desiccator <NUM> is brought to room temperature to correspondingly bring the substrate <NUM> and particles <NUM> to room temperature and ensure an accurate subsequent weight measurement. Once the glass slide <NUM> has been removed from the desiccator <NUM>, the filtration substrate <NUM> is weighed. The difference in weight of the filtration substrate <NUM> prior to the filtering step <NUM> and after the drying step <NUM> provides a filtration substrate <NUM> weight difference that provides the weight of the particles <NUM>. The weight of the particles <NUM> can correspond to the particles <NUM> of a single prosthetic orthopaedic component <NUM>. Alternatively, as described above, a plurality of prosthetic orthopaedic components <NUM> can be placed in the container <NUM>. Thus, the weight of the particles <NUM> can correspond to the particles of a plurality of orthopaedic components <NUM>.

Next, referring to <FIG>, a method <NUM> of analyzing the prosthetic orthopaedic component <NUM>, and in particular particles <NUM> from the prosthetic orthopaedic component <NUM>, can be performed after the method <NUM> has been completed. The method can determine at least one or more characteristic to all of the characteristics of <NUM>) the quantity of particles <NUM> disposed on the filtration substrate <NUM>, <NUM>) the sizes of the particles <NUM>, and <NUM>) the aspect ratios of the particles <NUM>. Additionally, the weight of the at least one particle <NUM> can be determined in the manner described above. As will be appreciated from the description below, the method <NUM> includes the step of viewing the particles <NUM> under microscope. Accordingly, as illustrated in <FIG>, after the filtration substrate <NUM> supporting the particles <NUM> has been weighed, the filtration substrate <NUM> is placed between optically transparent support members <NUM> so as to define a sample <NUM>, which can be configured as glass slides as described above. Thus, the bottom surface of the filtration substrate <NUM> is supported by a first glass slide <NUM>, and a second glass slide <NUM> can cover the top surface of the filtration substrate <NUM>. The second glass slide can be attached to the first glass slide, so that the filtration substrate <NUM> is captured between the first and second glass slides <NUM>. The first and second glass slides <NUM> are then attached to each other, for instance using any suitable adhesive <NUM> such as tape. While it is appreciated that the particles <NUM> can be disposed on the filtration substrate <NUM> when placed under the microscope in one example, it should be appreciated that the particles <NUM> can be transferred from the filtration substrate <NUM> to any alternative substrate suitable for supporting the particles <NUM> as desired.

As illustrated in <FIG>, a particle analysis station <NUM> includes a microscope <NUM>, an input device <NUM>, and a display <NUM>. The input device <NUM> can be configured as a joystick <NUM>, a keyboard <NUM>, a mouse, any suitable alternative input device, or any desired combination thereof. The particle analysis station <NUM> further includes a processor that is in data communication with the input device <NUM> and the display <NUM>. The processor is configured to operates a stored program that is configured to analyze the particles placed under the microscope <NUM>. The stored program can be a Filtrex software program commercially available by Microvision Instruments having a place of business in Evry, France, or any suitable alternative software configured to perform an analysis of the particles as will now be described.

Referring now to <FIG>, the method <NUM> can include the step <NUM> of obtaining an image <NUM> of the particles <NUM> on the filtration substrate <NUM>. In particular, the obtained image <NUM> can be a magnified image <NUM> of at least a portion of the filtration substrate <NUM> and the particles <NUM> supported on the filtration substrate <NUM>. In some embodiments, it is desirable for the magnified image <NUM> to include an entirety of the filtration substrate <NUM> to ensure that the image <NUM> includes all particles <NUM> supported by the filtration substrate <NUM>. For instance, the filtration substrate <NUM> and the particles <NUM> are placed under the microscope <NUM>. In one example, the sample <NUM> can be placed under the microscope <NUM>, such that the filtration substrate <NUM> and the particles <NUM> are in the field of view. The microscope <NUM> thus creates the magnified image <NUM> and outputs the magnified image <NUM> to the processor, which in turn outputs the magnified image <NUM> to the display <NUM>.

The microscope <NUM> has settings that can be adjusted so as to provide a desirable image <NUM>. For instance, the magnification can be set as desired, along with illumination that is applied to the filtration substrate and the particles <NUM>. In one example, the magnification can be set at <NUM> times or any suitable alternative magnification as desired. Further, it can be desirable to provide substantially uniform illumination to the filtration substrate <NUM>. The substrate <NUM> and the particles <NUM> can be illuminated by the microscope <NUM> under reflected light illumination. In one embodiment, the filtration substrate <NUM> and the particles <NUM> can be illuminated by the microscope <NUM> under reflected light illumination differential interference contrast microscopy (DIC). The particles <NUM> are brought into focus on the image <NUM>, such that the particles <NUM> are visually distinguishable from the filtration substrate <NUM> on the image <NUM>.

The software or other software can receive information regarding the sample <NUM>. For instance, the user can input a unique identified or the sample <NUM>. Further, the user can input the weight change of the filtration substrate <NUM> as described above, along with the number of prosthetic orthopaedic implants <NUM> from which the particles <NUM> supported by the filtration substrate <NUM> were removed.

Next, referring again to <FIG> and <FIG>, the method <NUM> can include the step <NUM> of identifying a region of interest <NUM> that includes the plurality of particles <NUM>. The region of interest <NUM> can include all particles <NUM> that are supported by the filtration substrate <NUM>. The user can input the region of interest <NUM> on the image <NUM>. The plurality of particles <NUM> can be arranged in groups <NUM> of particles that are spaced from each other in their respective entireties. The quantity of groups <NUM> of particles <NUM> can be determined as the number of areas defined inside respective boundary lines described above. Alternatively, at least one of the groups <NUM> of particles <NUM> can define a single particle <NUM>. In one example, the user can identify the outer perimeter <NUM> of the filtration substrate <NUM> as defining the region of interest <NUM>. Alternatively, the user can identify any suitable shape inside the outer perimeter <NUM> as the region of interest <NUM>. The user can draw a continuous shape that encloses the region of interest <NUM>, or can identify a plurality of points that lie on a continuous shape that defines the region of interest <NUM>. The focus and illumination described above remains applied to the region of interest <NUM>, or can be adjusted if desired to within a predetermined illumination range.

Next, referring to <FIG> and <FIG>, at step <NUM> a threshold is applied to the image <NUM> so as to identify an outer perimeter of each of the groups of at least one particle <NUM>. In particular, a color threshold can be applied to the image <NUM> inside the region of interest <NUM> so as to surround each of the groups <NUM> of particles <NUM> with a respective boundary line <NUM>. In one example, the boundary lines <NUM> can substantially extend along the outer perimeters of the groups <NUM> of particles <NUM>, respectively. Accordingly, the software identifies the particles as the area surrounded by the boundary lines <NUM>. Otherwise stated, the area defined inside the boundary lines <NUM> represent the respective at least one particle <NUM> or group <NUM> of particles <NUM>. Analysis on size and shape of the groups <NUM> of particles <NUM> can thus be performed based on a corresponding analysis of the area surrounded by the boundary lines <NUM>. In one example, the color threshold can be a gray threshold. In particular, it is recognized that in grayscale, the filtration substrate <NUM> media has a lighter grayscale hue than the particles <NUM>. Thus, the thresholding can be set to eliminate images lighter than the threshold setting. The software can display a thresholding selection bar that can be adjusted until only the perimeters of the groups <NUM> of particles <NUM> are identified. It should be appreciated that while the thresholding is performed in grayscale in one example, the thresholding can be performed for any suitable color as desired based on the color of the particles <NUM> and the substrate <NUM> that supports the particles <NUM>. Further, while the thresholding eliminates images lighter than the threshold setting in one example, the thresholding can alternatively eliminate images darker than the threshold setting in other examples, depending on the colors and hues of the particles <NUM> and the substrate <NUM>.

Referring again to <FIG>, once the perimeters of the groups <NUM> of particles <NUM> have been identified at the thresholding step <NUM>, the method <NUM> advances to step <NUM> whereby an analysis of the groups of particles <NUM> can be performed. In particular, the software can scan the area inside each of the boundary lines <NUM> generated during the thresholding step <NUM>. In this regard, the software can determine a quantity of the groups <NUM> of at least one particle <NUM>. Further, the software can measure a size of each of the groups <NUM> of at least one particle <NUM>. For instance, the software can determine a distance of the perimeters, respectively, of the groups <NUM>. Further, the software can determine respective two perpendicular dimensions of the groups <NUM> of particles <NUM>, respectively. The dimensions can be oriented along the upper surface of the filtration substrate <NUM>. Further, the dimensions can include a first dimension that extends along a direction of greatest length of the groups <NUM> of particles <NUM>, respectively. The dimensions can include a second dimension that is substantially perpendicular to the first direction. In this manner, the respective aspect ratio of each of the groups <NUM> of particles <NUM> can be determined. Further an area of each of the groups <NUM> of particles <NUM> can be measured along the upper surface of the filtration substrate <NUM>. Thus, a cumulative area of all particles <NUM> can be calculated as the sum of the areas of all of the groups <NUM> of particles <NUM>.

The method <NUM> can further include the step of comparing the at least one determined characteristic to a predetermined threshold. If the determined characteristic is greater than the threshold characteristic, the prosthetic orthopaedic component <NUM> can be discarded. If the determined characteristic is within the threshold characteristic, the prosthetic orthopaedic component <NUM> can be used as an anatomical implant. For example, if the quantity of determined particles <NUM> is greater than a predetermined quantity of approved particles <NUM>, the prosthetic orthopaedic component <NUM> can be deemed unsuitable for implantation. Similarly, if the determined weight of the particles <NUM> is greater than a predetermined weight, the prosthetic orthopaedic component can be deemed unsuitable for implantation.

As described above, the porous structure <NUM> can be manufactured using any suitable additive manufacturing process that involve the use of digital 3D design data to build up a metal component up in layers by depositing successive layers of material. Additive manufacturing processes can include, only by way of example, powder bed fusion printing method (e.g., melting and sintering), cold spray 3D printing, wire feed 3D printing, fused deposition 3D printing, extrusion 3D printing, liquid metal 3D printing, stereolithography 3D printing, binder jetting 3D printing, material jetting 3D printing, and so on.

In various examples, a method for producing the porous three-dimensional structure <NUM> comprises depositing and scanning successive layers of metal powders with a beam to form the porous three-dimensional structure. The beam (or scanning beam) can be an electron beam. The beam (or scanning beam) can be a laser beam. The metal powders can be sintered to form the porous three-dimensional structure. Alternatively, the metal powders can be melted to form the porous three-dimensional structure. The successive layers of metal powders can be deposited onto a solid base (see above for discussion regarding base).

Another method for producing the porous three-dimensional structure <NUM> comprises applying a stream of metal particles at a predetermined velocity onto a base to form the porous three-dimensional structure. The predetermined velocity can be a critical velocity required for the metal particles to bond upon impacting the base. The critical velocity is greater than <NUM>/s in some embodiments. The method can further include applying a laser at a predetermined power setting onto an area of the base where the stream of metal particles is impacting.

Another method for producing the porous three-dimensional structure <NUM> comprises introducing a continuous feed of metal wire onto a base surface and applying a beam at a predetermined power setting to an area where the metal wire contacts the base surface to form a porous three-dimensional structure comprising a plurality of unit cells and having predetermined geometric properties. The beam (or scanning beam) can be an electron beam. The beam (or scanning beam) can be a laser beam. The types of metal wire that can be used include, but are not limited to, titanium, titanium alloys, stainless steel, cobalt chrome alloys, tantalum or niobium wire.

Another method for producing the porous three-dimensional structure comprises introducing a continuous feed of a polymer material embedded with metal elements onto a base surface. The method can further comprise applying heat to an area where the polymer material contacts the base surface to form a porous three-dimensional structure comprising a plurality of unit cells and having predetermined geometric properties. The continuous feed of the polymer material can be supplied through a heated nozzle thus eliminating the need to apply heat to the area where the polymer material contacts the base surface to form the porous three-dimensional structure. The method can further comprise scanning the porous three-dimensional structure with a beam to burn off the polymer material. The beam (or scanning beam) can be an electron beam. The beam (or scanning beam) can be a laser beam.

Another method for producing the porous three-dimensional structure <NUM> comprises introducing a metal slurry through a nozzle onto a base surface. The nozzle is heated at a temperature required to bond metallic elements of the metal slurry to the base surface. In various examples, the metal slurry is an aqueous suspension containing metal particles along with one or more additives (liquid or solid) to improve the performance of the manufacturing process or the porous three-dimensional structure. In various examples, the metal slurry is an organic solvent suspension containing metal particles along with one or more additives (liquid or solid) to improve the performance of the manufacturing process or the porous three-dimensional structure.

Another method for producing the porous three-dimensional structure <NUM> comprises introducing successive layers of molten metal onto a base surface to form the porous three-dimensional structure. The molten metal can be introduced as a continuous stream onto the base surface. The molten metal can also be introduced as a stream of discrete molten metal droplets onto the base surface.

Another method for producing the porous three-dimensional structure <NUM> comprises applying and photoactivating successive layers of photosensitive polymer embedded with metal elements onto a base surface.

Another method for producing the porous three-dimensional structure comprises depositing and binding successive layers of metal powders with a binder material to form a porous three-dimensional structure comprising a plurality of unit cells and having predetermined geometric properties. The method can further include sintering the bound metal powder with a beam. The beam (or scanning beam) can be an electron beam. The beam (or scanning beam) can be a laser beam. The method can further include melting the bound metal powder with a beam. The beam (or scanning beam) can be an electron beam. The beam (or scanning beam) can be a laser beam.

Another method for producing the porous three-dimensional structure <NUM> comprises depositing droplets of a metal material onto a base surface, and applying heat to an area where the metal material contacts the base surface. The heat can be applied using a beam (or scanning beam) that can be an electron beam. The beam (or scanning beam) can be a laser beam. The deposited droplets of metal material can be a metal slurry embedded with metallic elements. The metal material can be a metal powder.

While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such an illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments have been shown and described and that all changes and modifications that come within the scope of the invention are desired to be protected.

Claim 1:
A method for removing at least one particle [<NUM>] from an additively manufactured orthopaedic prosthetic component [<NUM>] configured to be implanted in a patient's body, the method comprising the steps of:
submersing at least a portion of the additively manufactured orthopaedic prosthetic component [<NUM>] in a liquid [<NUM>];
sonicating at least a portion of the additively manufactured orthopaedic prosthetic component [<NUM>] with a high frequency vibration so as to loosen the at least one particle [<NUM>]; and
shaking the additively manufactured orthopaedic prosthetic component [<NUM>] to a low frequency vibration that is less than the high frequency vibration so as to evacuate the loosened at least one particle [<NUM>] from the additively manufactured orthopaedic prosthetic component [<NUM>].