Patent Application
20240041605
The present disclosure pertains to orthopedic implants including porous structures with varying surface roughness.
Certain orthopedic implants, such as prosthetic joint components used in joint replacement procedures, can be secured in the appropriate bone with cement, or by cementless fixation. In cementless fixation, the implant typically includes a porous structure that engages the native tissue when the implant is received in the prepared bone. For example, in a total hip replacement (hip arthroplasty) procedure, the acetabular cup can include a porous structure that engages the native tissue of the acetabular socket. The preparation is typically undersized relative to the size of the implant to facilitate an interference fit between the implant and the native tissue. The porous structure of the implant promotes stability by limiting movement of the implant relative to the bone to facilitate bone ingrowth. However, such porous structures typically have a uniformly high coefficient of friction with bone tissue, and strongly engage the bone upon surface contact. Thus, attempting to reposition such an implant after initial placement typically destroys the preparation by damaging the surrounding tissue, resulting in the need to remove the implant (often causing further tissue damage) and prepare the implantation site again. Accordingly, there exists a need for improved orthopedic implants configured for cementless fixation that permit in situ repositioning of the implant during implantation.
The present disclosure pertains to orthopedic implants including porous structures with varying surface roughness. In a representative example, an orthopedic implant comprises an implant body defining a longitudinal axis extending in a direction of implantation of the orthopedic implant, the implant body having a first end portion and a second end portion; and a porous structure extending circumferentially around the implant body, the porous structure comprising a first circumferentially-extending zone exhibiting a first coefficient of friction with bone tissue and a second circumferentially-extending zone exhibiting a second coefficient of friction with bone tissue, wherein the second coefficient of friction is greater than the first coefficient of friction; and wherein the first circumferentially-extending zone of the porous structure is offset from the second circumferentially-extending zone along the longitudinal axis such that during implantation of the orthopedic implant, the first circumferentially-extending zone of the porous structure contacts bone before the second circumferentially-extending zone of the porous structure.
In another representative embodiment, an orthopedic implant comprises an implant body defining a longitudinal axis extending in a direction of implantation of the orthopedic implant, the implant body having a first end portion and a second end portion. The implant body has a thickness dimension defined perpendicular to the longitudinal axis, the thickness dimension of the implant body increasing in a direction along the longitudinal axis from the first end portion to the second end portion. The implant body comprises a porous structure extending along the longitudinal axis, the porous structure comprising a plurality of struts arranged in a three-dimensional arrangement, the porous structure comprising a transition zone in which the porous structure gradually develops from a solid bulk material of the implant body over a selected distance.
In another representative embodiment, an orthopedic implant comprises an implant body defining a longitudinal axis extending in a direction of implantation of the orthopedic implant, the implant body having a first end portion and a second end portion; and a porous structure extending circumferentially around the implant body, the porous structure comprising a first circumferentially-extending zone exhibiting a first coefficient of friction with bone tissue and a second circumferentially-extending zone exhibiting a second coefficient of friction with bone tissue, wherein the second coefficient of friction is greater than the first coefficient of friction.
In another representative embodiment, an orthopedic implant comprises an implant body defining a longitudinal axis extending in a direction of implantation of the orthopedic implant, the implant body having a first end portion and a second end portion; the implant body having a thickness dimension defined perpendicular to the longitudinal axis, the thickness dimension of the implant body increasing in a direction along the longitudinal axis from the first end portion to the second end portion; and the implant body comprising a porous structure extending along the longitudinal axis, the porous structure exhibiting a coefficient of friction with bone tissue that decreases along the porous structure in a direction of implantation of the orthopedic implant.
In another representative embodiment, an orthopedic implant comprises an implant body comprising a solid substrate and a porous bone-contacting structure on the solid substrate, the porous bone-contacting structure comprising a plurality of angled strut members extending outwardly from the solid substrate of the implant body; wherein a first portion of the strut members of the porous bone-contacting structure extend from the solid substrate by a specified distance or less; and wherein a second portion of the strut members of the porous bone-contacting structure extend beyond the specified distance and comprise pointed end portions.
The foregoing and other objects, features, and advantages of the disclosed technology will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
Orthopedic implants for use in joint replacement procedures are typically configured to be held in place using bone cement or, alternatively, to be press-fitted into the bone and held in place by frictional engagement with the surrounding tissue. Such “cementless” implants can include one or a plurality of regions comprising a porous structure configured to exhibit a high coefficient of friction with bone or other native tissue, and to promote bone ingrowth for long term stabilization of the implant. In certain examples, such porous structures can comprise a three-dimensional scaffold and/or lattice comprising a plurality of angled, interconnected members, struts and/or rods, referred to hereinafter as strut members. The strut members can be arranged to define openings and/or pores between them, and throughout the extent of the three-dimensional porous structure. In certain embodiments, the three-dimensional porous structure can be formed using three-dimensional printing and/or additive manufacturing techniques.
In certain examples, the surface roughness of the three-dimensional porous structure can be varied at different locations on a porous structure of an implant to vary its adhesion with bone or other native tissue. For example, in certain embodiments the porous structure of an implant can be configured such that the surface of the porous structure comprises a plurality of regions or zones having different surface roughness values, and thereby exhibiting different coefficients of friction with bone or other native tissue. In certain embodiments, the porous structure can be configured such that its surface roughness, and thereby its coefficient of friction with bone or other native tissue, varies continuously along the surface of the porous structure in a particular direction, such as in the direction of implantation.
In certain embodiments, the strut members of the porous structure can be formed on a solid substrate of the implant body, and can extend outwardly from the solid substrate surface. In certain embodiments, the surface roughness of the three-dimensional porous structure can be at least partially determined based on end conditions and/or end structures of the strut members. For example, in certain embodiments the surface roughness of the three-dimensional porous structure can be at least partially determined by variation in length of strut members in the porous structure relative to a reference line, a reference plane, or a reference surface of the implant located a specified distance from the solid substrate surface. For example, the surface roughness can be varied by varying one or more of the following parameters: (a) the number of strut members that extend beyond, or end short of, the reference line/plane/surface; (b) the distance by which strut members extend beyond, or end short of, the reference line/plane/surface; and/or (c) the shape and/or dimensions (e.g., width, diameter, taper, angle, etc.) of the end portions of the strut members.
Varying the parameters above, or combinations thereof, can result in variations in the coefficient of friction of the surface of the porous structure with bone or other native tissue. This can allow certain porous structures of an implant, or portions of the surfaces of such porous structures, to exhibit a higher or lower coefficient of friction than others. In a representative embodiment, the strut members of a high-friction zone of a porous structure can have angular, irregular, and/or pointed end portions, and can end at various heights, thereby increasing the surface roughness of the zone. Conversely, the strut members of a low-friction zone of the porous structure can have rounded end portions, and/or can have heights that are the same or substantially the same as each other, thereby reducing the surface roughness of the zone.
Thus, according to the embodiments described herein, the surface of a porous structure of an implant can be configured such that region(s) of the porous structure that contact native tissue early in the implantation process can exhibit a relatively lower coefficient of friction than region(s) that contact the native tissue subsequently. For example, the portion(s) of a porous structure of an implant that contact native tissue only as the implant nears its final position can exhibit a relatively higher coefficient of friction than portions that contact tissue initially. This can be particularly useful, for example, when adjustment of the position and/or orientation of an implant relative to the bone may be indicated mid-placement, before final positioning of the implant. For example, with lower friction portions of the surface of the porous structure in contact with the native tissue, the implant can be rotated, moved proximally or distally, etc., more easily and with reduced damage to the tissue of the prepared implantation site. In certain embodiments, although different portions of the surface can have relatively higher or relatively lower surface roughness, the underlying three-dimensional porous structure can be the same, facilitating bone growth into all regions of the porous structure regardless of surface roughness and frictional engagement with the surrounding bone.
The porous structure embodiments described herein can also be applicable to any of a variety of implants for different orthopedic procedures, including hip arthroplasty, knee replacement, ankle replacement, elbow replacement, etc. For purposes of illustration, the orthopedic implants shown and described herein are configured for use in canine orthopedic procedures. However, the specific examples provided herein are not intended to be limiting, and the porous structure embodiments of the present disclosure can be adapted for use on orthopedic implants for a wide variety of human and/or veterinary orthopedic procedures.
In a total hip replacement procedure (also known as hip arthroplasty), the articular surfaces of the native hip joint are replaced with prosthetic implants that are secured to the pelvis and the femur to form a ball-and-socket joint. The prosthetic joint assembly typically includes a femoral hip step that is inserted into the canal of the femur, a femoral head typically including a spherical bearing or ball coupled to the femoral hip stem, and an acetabular cup that is inserted into the acetabulum of the pelvis and configured to receive the prosthetic femoral head. In a typical procedure, the femur is separated from the acetabulum, and the native femoral head is removed from the femur. The acetabulum is prepared using a multi-step reaming process to remove tissue and expose healthy bone, typically with a reamer that is smaller than the acetabular cup diameter. The acetabular cup implant is secured in the prepared acetabulum. In certain examples, the cup may be press-fitted into place (e.g., by impact), and/or may be cemented into the socket. The femur is axially reamed to create an opening into which the femoral stem prosthesis can be inserted. The femoral stem prosthesis can also be press-fitted and/or cemented into place, depending upon the particular indication. The prosthetic femoral head can be attached to the femoral stem prosthesis, and the femur can be maneuvered into place such that the prosthetic femoral head is received in the acetabular cup to form a prosthetic hip joint.
In the embodiment illustrated in
In certain examples, the porous structure can comprise a three-dimensional scaffold and/or lattice structure/arrangement comprising a plurality of angled, interconnected strut members. The strut members can be arranged to define openings and/or pores between them. For example,
As noted above, in certain embodiments the porous structure can be configured such that it exhibits a coefficient of friction with bone tissue that varies along the surface of the porous structure. Such variation can be continuous along the surface of the porous structure in a particular direction (e.g., in the direction of implantation), or in discrete regions or zones exhibiting different coefficients of friction with bone tissue.
For example,
The annular portion 114 of the main body 102 can comprise a relatively smooth surface. The main body 102 can further comprise a porous bone-contacting structure generally indicated at 116, which can cover the entire or substantially the entire outer surface of the main body 102 distally of the annular portion 114. In certain embodiments, the porous structure 116 can cover the hemispherical second end portion 108, and can extend across the equator 117 of the second end portion and cover at least a portion of the cylindrical first end portion 106.
In the illustrated embodiment, the porous structure 116 comprises two discrete, circumferentially extending surface regions referred to herein as zones or surface zones 116A and 116B. The first zone 116A is located proximally of the annular portion 114 (e.g., downwardly along the axis 110) and encompasses the equator 117 of the hemispherical second end portion 108. The second zone 116B is located proximally of the first zone 116A, and encompasses the pole or proximal end of the hemispherical second end portion 108.
In certain embodiments, the surface roughness of the first zone 116A can be different from the surface roughness of the second zone 116B. For example, in certain embodiments the surface roughness of the second zone 116B can be greater than the surface roughness of the first zone 116A. In certain embodiments, the struts in the first zone 116A can have a different edge condition, end condition, and/or end structure than the struts in the second zone 116B. For example,
In certain embodiments, the end portions 126 of the strut members 122A can be flat, smooth, and/or rounded such that deviation from the specified distance 124, and thus the surface roughness in the first zone 116A, can be relatively low. The strut members 122B in the second zone 116B can be longer than the struts 122A, and can extend beyond the specified distance X. In certain embodiments, the strut members 122B can also comprise relatively angular, jagged, irregular, and/or pointed end portions 128. Accordingly, the surface roughness of the second zone 116B can be greater than the surface roughness of the first zone 116A. The pointed, irregular shapes of the end portions 128 of the strut members 122B can also contribute to an increased coefficient of friction with bone tissue as compared to the first zone 116A.
Referring to
The surface roughness of the porous structure 116 can be determined in a variety of ways. For example, in certain embodiments the arithmetic mean roughness parameter Ra of the porous structure 116 can be determined along a mean line, such as the dashed line 124 at the specified distance X from the solid substrate 118. The surface roughness can also be determined or expressed according to any of various other parameters, such as the range roughness parameter Rt, the root mean squared roughness parameter Rq, or any of various surface area roughness parameters.
In certain embodiments, the surface roughness of the first zone 116A can be such that the first zone 116A exhibits a coefficient of friction of 0.6 to 0.8 with cancellous bone tissue, such as 0.7 to 0.8, or 0.75 or less. In certain embodiments, the first zone 116A can exhibit a coefficient of friction of 0.6 to 0.8 with cancellous bone tissue, such as 0.7 to 0.8, or 0.75 or less. In certain embodiments, the surface roughness of the second zone 116B can be such that the second zone 116B exhibits a coefficient of friction of 0.8 to 1.0 with cancellous bone tissue, such as 0.85 to 0.95 or 0.8 or more. In certain embodiments, the second zone 116B can exhibit a coefficient of friction of 0.8 to 1.0 with cancellous bone tissue, such as 0.85 to 0.95 or 0.8 or more.
The extent of the first zone 116A and the second zone 116B as a proportion of the overall surface of the porous structure 116, and/or as a proportion of the overall height H of the implant, can vary. For example,
In certain embodiments, the height dimension y1 of the surface zone 130 can be 5% to 30% of the overall height H, such as 10% to 30%, 20% to 30%, 10% to 25%, or 10% to 20%. In certain embodiments, the height dimension y2 of the first zone 116A of the porous structure can be 10% to 50% of the overall height H, such as 10% to 40%, 20% to 50%, 20% to 40%, 10% to 30%, or 10% to 20%. In certain embodiments, the height dimension y3 of the second zone 116B of the porous structure can be 30% to 70% of the overall height H, such as 30% to 60%, 40% to 70%, or 40% to 60%. In particular embodiments, the height dimension y1 can be 20% of the overall height H, the height dimension y2 can be 30% of the overall height H, and the height dimension y3 can be 50% of the overall height H. In certain embodiments, the combined height dimensions y1 and y2 (e.g., collectively the “low friction” portion of the outer surface of the acetabular cup) can be 20% to 40% over the overall height H.
In use, varying the surface roughness of the implant body as described herein can allow rotation and/or reorientation of the implant about various axes after initial placement of the implant, and prior to impaction to its final position. In certain embodiments, by reducing the surface roughness of the portion(s) of the porous structure that contact native bone tissue first or early in the implantation process, the acetabular cup 100 can be rotated about nearly any axis.
For example,
Accordingly, the axis 110 of the acetabular cup 100 can be aligned with the axis 132 of the native acetabulum 131 by rotating the acetabular cup in the direction of arrow 134. In certain embodiments, this can be accomplished by tapping the acetabular cup with an impactor at the location and in the direction indicated by arrow 136. The aligned acetabular cup 100 and native acetabulum 131 are illustrated in
In certain embodiments, the solid shell 118 and the porous structure 116 can be made using three-dimensional printing or additive manufacturing techniques. For example, in certain embodiments the three-dimensional porous structure 116 can be formed on the solid shell 118 by applying metal powder or granules and sintering the powder together in a series of layers. In certain embodiments, the solid shell 118 can be molded or cast, and the porous structure 116 can be three-dimensionally printed on the surface of the solid shell 118. The variation in roughness between the various zones of the surface of the porous structure 116 can be provided by varying the shape and/or size of the end portions of the three-dimensionally printed struts in the various zones as described above.
In other embodiments, the porous structure 116 can have more than two zones, such as three zones, four zones, five zones, etc., each zone having a different surface roughness and/or exhibiting a different coefficient of friction with bone tissue. For example, the surface roughness of each zone can increase moving along the porous structure in the implantation direction. In yet other embodiments, the surface roughness can increase and decrease alternatingly along the surface of the porous structure in the implantation direction, depending upon the particular characteristics desired. The surface roughness of the porous structure 116 can also increase in the proximal direction from a first or minimum surface roughness at the distal edge of the porous structure 116 to a second or maximum surface roughness at the proximal edge (e.g., at the pole of the acetabular cup) in a continuous gradient.
Porous structures with varying surface roughness can also be implemented on femoral stem prostheses.
The proximal end portion 206 can have a region comprising a circumferentially-extending porous structure 210 configured to promote bone ingrowth to create mechanical interlocking between the femur and the femoral stem prosthesis, as described above. In the illustrated embodiment, the porous structure 210 can comprise a plurality of regions or zones having different surface roughness and/or exhibiting different coefficients of friction with bone material. In certain examples, portion(s) of the porous structure 210 that contact native bone tissue early in the implantation process can comprise a relatively low surface roughness. Portion(s) of the porous structure 210 that contact bone tissue later in the implantation process or at final impaction of the implant can comprise a relatively higher surface roughness, and can be offset longitudinally from the zones of lower surface roughness. For example, in the illustrated embodiment the porous structure 210 comprises a circumferentially-extending first or distal zone 210A having a relatively lower surface roughness, and a circumferentially-extending second or proximal zone 210B having a relatively higher surface roughness. Thus, the surface roughness and/or the coefficient of friction between the porous structure 210 and bone can decrease moving along the porous structure in the direction of implantation (e.g., downwardly along axis 212).
In certain embodiments, the distal zone 210A can extend along 70% to 90% of the overall axial length of the porous structure 210 (e.g., as measured along the longitudinal axis 212 of the stem member 202). In certain embodiments, the distal zone 210A can extend along 75% to 85% or 80% of the overall axial length of the porous surface 210. In certain embodiments, the proximal zone 210B can extend along 10% to 30% of the overall axial length of the porous structure 210, such as 15% to 25%, 10% to 20%, or 20% of the overall axial length of the porous structure 210.
In certain embodiments, the surface roughness of the distal zone 210A can be such that the distal zone 210A exhibits a coefficient of friction with cancellous bone tissue of 0.6 to 0.8, such as 0.7 to 0.8 or 0.75 or less, similar to the zone 116A of the acetabular cup 100. In certain embodiments, the distal zone 210A can exhibit a coefficient of friction with cancellous bone tissue of 0.6 to 0.8, such as 0.7 to 0.8 or 0.75 or less. In certain embodiments, the surface roughness of the proximal zone 210B can be such that the proximal zone 210B exhibits a coefficient of friction of 0.8 to 1.0 with cancellous bone tissue, such as 0.85 to 0.95 or 0.8 or more. In certain embodiments, the proximal zone 210B can exhibit a coefficient of friction of 0.8 to 1.0 with cancellous bone tissue, such as 0.85 to 0.95 or 0.8 or more.
In certain embodiments, the native femur can be broached or reamed to create a canal that has a slightly smaller size (e.g., diameter) than the stem member 202. The stem member 202 can be inserted into the femoral canal to create an interference or frictional fit for establishing initial stability of the femoral stem prosthesis 200. As the stem member 202 is advanced into the femur, the relatively low roughness/friction distal zone 210A of the porous structure 210 can contact bone tissue of the femur before the relatively higher roughness/friction proximal zone 210B. In certain embodiments, at least the distal zone 210A, or both the proximal zone 210B and the distal zone 210A, can be primarily in shear.
In other embodiments, the porous structure 210 can comprise any number of zones having different roughness/frictional characteristics, as described above. The surface roughness of the porous structure 210 can also decrease in the distal direction from a first or maximum surface roughness at the proximal edge of the porous structure 210 to a second or minimum surface roughness at the distal edge in a continuous gradient.
In certain embodiments, the acetabular cup 100 and/or the femoral stem prosthesis 200 can be formed of any of various biocompatible metal materials. For example, in certain embodiments the prostheses can be formed of titanium alloys, such as ASTM F-136 (Ti-6Al-4V ELI Titanium Alloy). In other embodiments, the acetabular cup 100 and/or the femoral stem prosthesis 200 can be formed using other biocompatible metals such as cobalt chromium, stainless steel, and/or various composite materials or polymers.
As noted above, porous structures with zones of differing roughness as described herein can be applicable to a variety of other orthopedic implants. For example,
The first member 302 can comprise a porous structure 312 on the radially inner surface or aspect configured to contact the humerus when implanted. The porous structure 312 can comprise a three-dimensional porous structure according to any of the embodiments described herein. In certain embodiments, the porous structure 312 can have strut members with rounded end portions and relatively uniform height as described above with reference to
In certain embodiments, a medial portion or zone 314 of the porous structure 312 can comprise a relatively lower surface roughness and correspondingly lower coefficient of friction than a lateral portion or zone 316 of the porous structure. For example, in certain embodiments the lateral zone 316 of the porous structure 312 can comprise strut members with angular, pointed end portions and varying heights as described above with reference to
In certain embodiments, the radially outward aspect of the second member 304 can comprise a porous structure 318. In certain embodiments, the porous structure 318 can comprise a relatively low surface roughness and coefficient of friction with bone, or a medial zone and a lateral zone configured similarly to the medial and later zones described above with reference to the porous structure 312.
The first member 402 can be configured for implantation at the distal end portion of the tibia and/or the fibula. The second member 404 can be configured for implantation at the proximal end portion of the talus bone. The radially outward (e.g., dorsal or proximal) aspect of the first member 402 can comprise one or a plurality of portions including three-dimensional porous structures according to any of the embodiments described herein. For example, in the illustrated embodiment the first member 402 comprises two porous structures, a porous structure 414 on a medial aspect or end portion of the first member 402, and a porous structure 416 on a lateral aspect or end portion of the first member 402. The porous structures 414 and 416 can be configured according to any of the porous structure embodiments described herein. In certain embodiments, the porous structures 414 and/or 416 can extend onto the medial or lateral surfaces, respectively, of the first member 402.
In certain embodiments, the medial porous structure 414 and the lateral porous structure 416 can both comprise strut members with rounded end portions and relatively uniform heights such that the porous structures 414 and 416 have a relatively low surface roughness and a relatively low coefficient of friction with bone (e.g., 0.6 to 0.8, or 0.75 or less with cancellous bone). In certain embodiments, the surface roughness and the coefficients of friction of the porous structures 414 and 416 can be different. For example, in certain embodiments the surface roughness and coefficient of friction of the medial porous structure 414, which can encounter bone first as the implant 400 is implanted, can be lower than the surface roughness and coefficient of friction of the lateral porous structure 416. In certain embodiments, the lateral porous structure 416 can comprise strut members with pointed end portions and varying heights, resulting in a relatively high surface roughness and a relatively high coefficient of friction with cancellous bone (e.g., 0.8 to 1.0, or 0.8 or more).
In certain embodiments, one or both of the porous structures 414 and/or 416 can comprise multiple regions or zones having different surface roughness and corresponding coefficients of friction with bone, as described above. In certain embodiments, the second member 404 can comprise a plurality of porous structures such as the porous structure 418 visible in
When the stem member 504 is inserted into the prepared tibia, the porous structure 510 can contact the proximal end portion of the tibia, and the relatively high surface roughness of the porous structure 510 can frictionally engage the tibia to inhibit motion of the implant 500. In certain embodiments, the porous structure 510 can comprise zones of greater or reduced roughness, as described above.
The femoral implant prosthesis 520 can define a curved outer surface generally indicated at 532. The outer surface 532 can be continuous along the cranial portion 526, the base portion 524, and the caudal portion 528, and can be configured to engage the tibial prosthesis 500 of
The inner aspect of the U-shaped main body 522 can comprise a plurality of bone-contacting surfaces or facets. For example, the base portion 524 can comprise two inner surfaces 534 and 536 angled toward each other and meeting at an apex 538. The cranial portion 526 can comprise an inner surface 542, and the caudal portion 528 can comprise an inner surface 544 facing the inner surface 542 of the cranial portion 526 across the gap 540. In certain embodiments, each of the inner surfaces 534, 536, 542, and/or 544 can comprise three-dimensional porous structures configured according to any of the embodiments described herein. For example, in certain embodiments the porous structures of the surfaces 534 and 536 of the base portion 524 can comprise strut members with pointed end portions and varying heights such that the porous structures have a relatively high surface roughness, and a corresponding relatively high coefficient of friction with bone (e.g., 0.8 to 1.0, or 0.8 or more, with cancellous bone). In certain embodiments, the porous structures of the surfaces 542 and 544 of the cranial portion 526 and the caudal portion 528, respectively, can comprise strut members with rounded end portions and relatively uniform heights such that the porous structures have a relatively low surface roughness and a corresponding relatively low coefficient of friction with bone (e.g., 0.6 to 0.8, or 0.75 or less, with cancellous bone). In certain embodiments, the porous structures of the surfaces 534, 536, 542, and 544 can be a single, continuous porous structure.
In certain embodiments, a width or thickness dimension W of the main body 522 measured in the cranial-caudal direction (e.g., perpendicular to the longitudinal axis 546) can increase from the base portion 524 moving along the longitudinal axis 546 of the implant in the direction indicated by arrow 548, which can be the implantation direction. Accordingly, the surface roughness/coefficient of friction of the porous structures can decrease moving in the implantation direction as the thickness dimension W increases. As the femoral implant prosthesis is advanced over the distal end portion of the femur, the porous structures at the surfaces 542 and 544 can contact bone tissue initially, followed by the surfaces 534 and 536 at final impaction/placement of the implant. The surfaces 542 and 544 can slide along native bone tissue of the femur during placement, aided by the relatively low surface roughness/friction of the porous structures. Once at its final position, the higher roughness/friction porous structures at the surfaces 534 and 536 can contact the bone and aid in retaining the implant in place. As in the previously described embodiments, the three-dimensional porous structures can provide for bone ingrowth at each of the surfaces 534, 536, 542 and 544 independent of the surface roughness of the porous structures to facilitate long term stability of the implant. At its final position, the surfaces 542 and 544 can be primarily in shear, and the surfaces 534 and 536 can be primarily in compression.
In certain embodiments, the porous structures of any or all of the surfaces 534, 536, 542 and/or 544 can comprise zones of varying surface roughness/friction, as described above. For example, in certain embodiments one or more of the surfaces 534, 536, 542 and/or 544 can comprise a lower roughness zone at a dorsal or proximal end of the surface (e.g., along the axis 546) where initial contact with bone is made during implantation, and a higher roughness zone at a ventral or distal end of the surface. In certain embodiments, the surface roughness of the porous structures can increase along the surfaces 534, 536, 542 and/or 544 in a distal direction in a continuous gradient.
The following example describes a representative test apparatus and method by which the coefficient of friction of a porous structure, such as any of the porous structures described herein, can be determined with respect to bone tissue.
The coefficient of static friction between the material of the test specimen 602 and the material of the surface layer 612 of the platform 608 can be determined by placing the disk 600 on the platform 608 with the test specimen 602 in contact with the surface layer 612. The platform 608 can then be inclined relative to the base 606 by rotating the free end of the platform upwardly in the direction indicated by arrow 616, and noting the angle of the platform at which the disk 600 begins to slide along the surface layer 612.
The normal force FN can be determined by the following equation: FN=mg sin θ, where m is the mass of the disk 600 and g is the acceleration due to gravity.
The friction force Ff can be determined by the following equation: Ff=mg cos θ.
The coefficient of static friction can be determined by the following equation:
Returning to
In a test, the test member 600A began to slide along the surface layer 612 at an angle of approximately 54°. The coefficient of static friction between the porous tantalum structure of the test member 600A and the polyurethane foam imitation cancellous bone material of the surface layer 612 was determined to be approximately 0.9.
In a test, the test member 600B began to slide along the surface layer 612 at an angle of approximately 51°. The coefficient of static friction between the relatively high surface roughness three-dimensional porous structure of test member 600B and the polyurethane foam imitation cancellous bone material of the surface layer 612 was determined to be approximately 0.87.
In a test, the test member 600C began to slide along the surface layer 612 at an angle of approximately 43°. The coefficient of static friction between the relatively low surface roughness three-dimensional porous structure of test member 600C and the polyurethane foam imitation cancellous bone material of the surface layer 612 was determined to be approximately 0.72.
In a test, the test member 600D began to slide along the surface layer 612 at an angle of approximately 41°. The coefficient of static friction between the sintered titanium beads of the test member 600D and the polyurethane foam imitation cancellous bone material of the surface layer 612 was determined to be approximately 0.7. The results of each test are illustrated graphically in the chart of
The three-dimensional porous structure embodiments and their placement at various locations on orthopedic implants as described herein can provide a number of significant advantages over existing orthopedic implants. For example, varying length of the strut members and the shape of their end portions to vary the surface roughness of the porous structure allows the coefficient of friction of the porous structure with bone to be controlled. Thus, one or more portions of a porous structure located on an implant surface which contacts native bone tissue early in the implantation process can have a relatively low surface roughness (e.g., struts of the porous structure can have rounded end portions and a generally uniform height), and a correspondingly low coefficient of friction with bone. This can facilitate not only insertion of the implant into the bone, but also repositioning of the implant mid-implantation because the relatively low coefficient of friction between the porous structure and the bone tissue reduces damage to the preparation as the implant is adjusted.
Additionally, one or more portions of a porous structure located on implant surfaces that come into contact with bone at or near the final position of the implant can have a relatively high surface roughness (e.g., struts of the porous structure can have angled and/or pointed end portions, and varying heights), and a correspondingly higher coefficient of friction with bone. Thus, when driven or impacted to its final position, these higher surface roughness zones of the porous structure can engage native bone tissue with a relatively high coefficient of friction to retain the implant at its final position. Because both the low surface roughness and the high surface roughness portions of the porous structure can have the same or similar cellular configuration/geometry (e.g., the same or similar strut diameter, pore size, etc.), bone can grow into all zones of the porous structure regardless of the surface roughness of the various zones to promote long term fixation of the implant. The shape of the struts of the porous structure, and thus the surface roughness and coefficient of friction, can be precisely controlled using additive manufacturing techniques when the porous structure is formed.
In certain examples, a porous structure such as shown in
In certain examples, a porous structure such as shown in
In certain examples, various porous lattice structures can be formed in different regions on the surface of an implant. The porous structures can also transition from a relatively low friction configuration to a relatively high friction configuration over a selected distance, and in one or a plurality of directions (e.g., in the direction of implantation). The surface of an implant can also transition from a solid bulk material to a porous structure over a selected distance, and in one or a plurality of directions. For example,
This transition can be accomplished by varying the diameter of the struts in a gradient that extends in a particular direction or directions. For struts with longitudinal axes oriented in the selected direction, the diameter of the struts can vary along their axes. For struts oriented in other directions, the diameter of the struts can change by a selected amount in increments moving in the selected direction. For example, with reference to
For example, the struts oriented parallel to the direction of the transition such as strut 804 can vary from a relatively thick first diameter at one end of the transition zone 810 to a thinner second diameter. In certain examples, the second diameter can be a specified diameter of the struts in the fully developed porous lattice, where, for example, a specified gap and/or pore size is achieved in the porous structure. In at least a portion of the transition zone 810, the diameter of the struts can be sufficient to close the pores between the struts while still exhibiting strut-like structure on the surface. Stated differently, the initial diameter of the struts can be sufficiently large such that the struts at least partially merge together. As the diameter of the struts decreases in the selected direction (e.g., along arrow 802), gaps and/or open volumes can appear between the struts and gradually grow in size until the lattice structure is fully developed with a specified strut diameter and pore size.
In certain examples, a pore size of the lattice can be 0.1 mm to 2 mm, such as 0.1 mm to 1.5 mm, 0.5 mm to 2 mm, 0.5 mm to 1.5 mm, 0.1 mm to 1 mm, etc. In a particular example, the struts oriented parallel to the direction of the transition along arrow 802 can vary from a first diameter of 0.6 mm to a second diameter of 0.3 mm over a distance of 1 mm to 50 mm, such as 1 mm to 40 mm, 1 mm to 30 mm, 1 mm to 20 mm, 1 mm to 10 mm, 1 mm to 5 mm, 10 mm to 50 mm, 10 mm to 40 mm, 10 mm to 30 mm, 10 mm to 20 mm, etc., along the arrow 802. For struts in other orientations such as 806 and 808, the strut diameter can decrease from a first diameter of 0.6 mm to a second diameter of 0.3 mm in increments of 0.1 mm to 20 mm, such as 1 mm to 20 mm, 1 mm to 10 mm, 1 mm to 5 mm, 1 mm to 3 mm, 1 mm to 2 mm, 0.5 mm to 20 mm, 0.5 mm to 10 mm, 0.5 mm to 5 mm, 0.5 mm to 3 mm, 0.5 mm to 2 mm, 0.5 mm to 1 mm etc., over sequential rungs of struts in the direction of arrow 802.
In certain examples, transition zones such as the transition zone 810 can exhibit a coefficient of friction with bone of 0.2 to 0.6, such as 0.2 to 0.5, 0.2 to 0.4, 0.3 to 0.6, 0.3 to 0.5, etc.
The porous structures above can be incorporated into any of the orthopedic implants described herein. For example,
The porous lattice structure 906 can comprise a plurality of zones configured to exhibit different coefficients of friction with bone. The zones can incorporate various of the porous lattice structures described above with reference to
In the illustrated example, the low friction zone 914 can be a transition zone similar to
Line 924 indicates the cross-sectional plane at which the porous lattice structure 906 reaches a set of specified parameters for strut diameter and pore size. The plane 924 indicates the beginning of the moderate friction zone 916. In certain examples, the porous structure in the moderate friction zone 916 can be configured similarly to the structure described with reference to
Line 926 indicates the cross-sectional plane at which the porous structure 906 transitions to a high friction configuration. The plane 926 can thus mark the beginning of the high friction zone 918. In certain examples, the porous structure in the high friction zone 918 can be configured similarly to the structure described with reference to
The various zones 914-918 of the porous structure can extend at least partially around the perimeter and/or circumference of the implant body. In the example illustrated in
The porous structure 906 can extend along a length L defined in a direction parallel to the arrow 923 (e.g., in the direction of the decrease in the strut diameter). The low friction zone 914 can thus extend a distance A in the direction of arrow 923. The moderate friction zone 916 can extend a distance B in the direction of arrow 923. The high friction zone 918 can extend a distance C in the direction of arrow 923. In certain examples, A+B+C=L.
In certain examples, the length A of the low friction zone 914 can be 5% to 50% of the overall length L of the porous structure 906, 5% to 40% of the overall length L of the porous structure 906, 5% to 30% of the overall length L of the porous structure 906, 5% to 20% of the overall length L of the porous structure 906, 5% to 10% of the overall length L of the porous structure 906, 10% to 50% of the overall length L of the porous structure 906, 10% to 40% of the overall length L of the porous structure 906, 10% to 30% of the overall length L of the porous structure 906, 10% to 20% of the overall length L of the porous structure 906, 20% to 50% of the overall length L of the porous structure 906, 20% to 40% of the overall length L of the porous structure 906, 20% to 30% of the overall length L of the porous structure 906, 30% to 50% of the overall length L of the porous structure 906, 30% to 40% of the overall length L of the porous structure 906, etc. In one particular example, the length A of the low friction zone 914 can be 33% of the overall length L of the porous structure 906.
In certain examples, the length B of the moderate friction zone 916 can be 5% to 50% of the overall length L of the porous structure 906, 5% to 40% of the overall length L of the porous structure 906, 5% to 30% of the overall length L of the porous structure 906, 5% to 20% of the overall length L of the porous structure 906, 5% to 10% of the overall length L of the porous structure 906, 10% to 50% of the overall length L of the porous structure 906, 10% to 40% of the overall length L of the porous structure 906, 10% to 30% of the overall length L of the porous structure 906, 10% to 20% of the overall length L of the porous structure 906, 20% to 50% of the overall length L of the porous structure 906, 20% to 40% of the overall length L of the porous structure 906, 20% to 30% of the overall length L of the porous structure 906, 30% to 50% of the overall length L of the porous structure 906, 30% to 40% of the overall length L of the porous structure 906, etc. In one particular example, the length B of the moderate friction zone 916 can be 33% of the overall length L of the porous structure 906.
In certain examples, the length C of the high friction zone 918 can be 5% to 50% of the overall length L of the porous structure 906, 5% to 40% of the overall length L of the porous structure 906, 5% to 30% of the overall length L of the porous structure 906, 5% to 20% of the overall length L of the porous structure 906, 5% to 10% of the overall length L of the porous structure 906, 10% to 50% of the overall length L of the porous structure 906, 10% to 40% of the overall length L of the porous structure 906, 10% to 30% of the overall length L of the porous structure 906, 10% to 20% of the overall length L of the porous structure 906, 20% to 50% of the overall length L of the porous structure 906, 20% to 40% of the overall length L of the porous structure 906, 20% to 30% of the overall length L of the porous structure 906, 30% to 50% of the overall length L of the porous structure 906, 30% to 40% of the overall length L of the porous structure 906, etc. In one particular example, the length C of the high friction zone 918 can be 33% of the overall length L of the porous structure 906.
The coefficient of friction of the porous structure can thus decrease moving along the stem of the implant in the direction of implantation (e.g., downwardly along the longitudinal axis in
In certain examples, the porous structure can comprise multiple transition zones in which the porous lattice gradually develops along multiple axes and/or originates from multiple planes in different orientations. For example,
In certain examples, the porous lattice structures described herein can be shaped and sized to conform to the shape or outer profile of a particular implant. For example,
The porous structure 1106 can comprise a plurality of zones exhibiting different coefficients of friction with bone, as described previously. For example, the porous structure 1106 can comprise a first, relatively low friction zone 1108 at the upper latitudes of the cup, a second, moderate friction zone 1110 at the middle latitudes of the cup, and a third, relatively high friction zone 1112 at the equatorial latitudes of the cup. In the illustrated example, the low friction zone 1108 can include a transition region 1114 in which the struts decrease in diameter moving along their axes from the pole toward the equator of the cup. In certain examples, the low friction zone 1108 can include a cap or region 1116 of solid material at the pole of the cup. The transition zone 1114 can begin at the circumferential edge 1118 of the cap 1116 and can extend in a direction toward the equator.
A latitudinal line 1120 can indicate the end of the low friction zone 1108 and the start of the moderate friction zone 1110. Struts in the moderate friction zone 1110 can be shaped and sized similarly to those describe above with reference to
A latitudinal line 1122 can indicate the end of the moderate friction zone 1110 and the start of the high friction zone 1112. Struts in the high friction zone 1112 can be shaped and sized similar to those described above with reference to
In the illustrated embodiment, the second end portion 1104 can include a circumferential rim or ring 1124 of solid material at the equator of the cup, although other configurations are possible. The rim 1124 can form the lower or distal circumferential boundary of the high friction zone 1112.
In certain examples, the various zones of the porous structure 1106 can extend along portions of the overall height of the acetabular cup similar to the embodiment of
In certain examples, the moderate friction zone 1110 can be 5% to 60% of the overall height of the acetabular cup as measured along the longitudinal axis, such as 5% to 50%, 5% to 40%, 5% to 30%, 5% to 20%, 5% to 10%, 10% to 60%, 10% to 50%, 10% to 40%, 10% to 30%, 10% to 20%, 20% to 60%, 20% to 50%, 20% to 40%, 20% to 30%, 30% to 60%, 30% to 50%, 30% to 40%, 40% to 60%, etc., of the overall height of the cup as measured along the longitudinal axis (see
In certain examples, the high friction zone 1112 can be 5% to 50% of the overall height of the acetabular cup as measured along the longitudinal axis, such as 5% to 40%, 5% to 30%, 5% to 20%, 5% to 10%, 10% to 50%, 10% to 40%, 10% to 30%, 10% to 20%, 20% to 50%, 20% to 40%, 20% to 30%, 30% to 50%, 30% to 40%, etc., of the overall height of the cup as measured along the longitudinal axis (see
In certain examples, the porous lattice structures above can be formed using any of a variety of additive manufacturing processes, such as direct metal laser sintering, electron beam melting, etc.
In view of the above described implementations of the disclosed subject matter, this application discloses the additional examples enumerated below. It should be noted that one feature of an example in isolation or more than one feature of the example taken in combination and, optionally, in combination with one or more features of one or more further examples are further examples also falling within the disclosure of this application.
Example 1. An orthopedic implant, comprising: an implant body defining a longitudinal axis extending in a direction of implantation of the orthopedic implant, the implant body having a first end portion and a second end portion; and a porous structure extending circumferentially around the implant body, the porous structure comprising a first circumferentially-extending zone exhibiting a first coefficient of friction with bone tissue and a second circumferentially-extending zone exhibiting a second coefficient of friction with bone tissue, wherein the second coefficient of friction is greater than the first coefficient of friction; and wherein the first circumferentially-extending zone of the porous structure is offset from the second circumferentially-extending zone along the longitudinal axis such that during implantation of the orthopedic implant, the first circumferentially-extending zone of the porous structure contacts bone before the second circumferentially-extending zone of the porous structure.
Example 2. The orthopedic implant of any example herein, particularly example 1, wherein: the porous structure comprises a plurality of struts arranged in a three-dimensional arrangement; and the first circumferentially-extending zone comprises a transition zone in which a diameter of the struts decreases from a first diameter to a second diameter that is less than the first diameter.
Example 3. The orthopedic implant of any example herein, particularly example 2, wherein the diameter of the struts decreases in a direction that is at an angle to the longitudinal axis of the implant body.
Example 4. The orthopedic implant of any example herein, particularly example 2 or example 3, wherein the porous structure further comprises a second transition zone, and a diameter of struts in the second transition zone decreases in a different direction than in the first transition zone.
Example 5. The orthopedic implant of any example herein, particularly any one of examples 1-4, wherein struts of the second circumferentially-extending zone comprise a specified diameter along their lengths.
Example 6. The orthopedic implant of any example herein, particularly any one of examples 1-5, wherein the porous structure further comprises a third circumferentially-extending zone exhibiting a third coefficient of friction with bone that is higher than the first coefficient of friction and higher than the second coefficient of friction.
Example 7. The orthopedic implant of any example herein, particularly example 6, wherein struts of the third circumferentially-extending zone comprise a plurality of prominences and recesses that increase the third coefficient of friction.
Example 8. The orthopedic implant of any example herein, particularly any one of examples 1-7, wherein strut members of the first circumferentially-extending zone and/or the second circumferentially-extending zone comprise rounded end portions.
Example 9. The orthopedic implant of any example herein, particularly any one of examples 6-8, wherein end portions of the strut members of the third circumferentially-extending zone are pointed.
Example 10. The orthopedic implant of any example herein, particularly any one of examples 6-9, wherein strut members of the second circumferentially-extending zone and/or the third circumferentially-extending zone extend radially outwardly beyond strut members of the first circumferentially-extending zone.
Example 11. The orthopedic implant of any example herein, particularly any one of examples 1-10, wherein: the first circumferentially-extending zone of the porous structure exhibits a coefficient of friction with cancellous bone tissue of 0.2 to 0.5; and the second circumferentially-extending zone of the porous structure exhibits a coefficient of friction with cancellous bone tissue of 0.4 to 0.6.
Example 12. The orthopedic implant of any example herein, particularly any one of examples 6-11, wherein the third circumferentially-extending zone of the porous structure exhibits a coefficient of friction with cancellous bone tissue of 0.7 to 1.1.
Example 13. The orthopedic implant of any example herein, particularly any one of examples 6-12, wherein the orthopedic implant is an acetabular cup, and the third circumferentially-extending zone of the porous structure is disposed at least partially on the second end portion.
Example 14. The orthopedic implant of any example herein, particularly example 13, wherein a height of the third circumferentially-extending zone of the porous structure measured along the longitudinal axis is 10% to 40% of an overall height of the acetabular cup measured along the longitudinal axis.
Example 15. The orthopedic implant of any example herein, particularly any one of examples 6-12, wherein the orthopedic implant is a femoral stem prosthesis, and the third circumferentially-extending zone of the porous structure is at a proximal end of the porous structure.
Example 16. The orthopedic implant of any example herein, particularly example 15, wherein a height of the third circumferentially-extending zone of the porous structure measured in a direction of the strut diameter decrease in the transition zone is 10% to 40% of an overall height of the porous structure measured in the direction of the strut diameter decrease in the transition zone.
Example 17. An orthopedic implant, comprising: an implant body defining a longitudinal axis extending in a direction of implantation of the orthopedic implant, the implant body having a first end portion and a second end portion; the implant body having a thickness dimension defined perpendicular to the longitudinal axis, the thickness dimension of the implant body increasing in a direction along the longitudinal axis from the first end portion to the second end portion; and the implant body comprising a porous structure extending along the longitudinal axis, the porous structure comprising a plurality of struts arranged in a three-dimensional arrangement, the porous structure comprising a transition zone in which the porous structure gradually develops from a solid bulk material of the implant body over a selected distance.
Example 18. The orthopedic implant of any example herein, particularly example 17, wherein the porous structure exhibits a coefficient of friction with bone tissue that decreases along the porous structure in a direction of implantation of the orthopedic implant.
Example 19. The orthopedic implant of any example herein, particularly example 17 or example 18, wherein a diameter of the struts of the transition zone decreases in a direction that is at an angle to the longitudinal axis of the implant body.
Example 20. The orthopedic implant of any example herein, particularly example 17 or example 18, wherein: the transition zone is a first zone of the porous structure and exhibits a first coefficient of friction with bone; and the porous structure further comprises a second zone and a third zone, the second zone being offset from the first zone in the direction of implantation and the third zone being offset from the second zone in the direction of implantation such that the second zone is between the first zone and the third zone, and such that the first zone contacts bone before the second zone of the porous structure during implantation; wherein the third zone exhibits a coefficient of friction with bone tissue that is greater than a coefficient of friction with bone tissue exhibited by the second zone.
Example 21. The orthopedic implant of any example herein, particularly example 20, wherein struts of the second zone comprise a specified diameter along their lengths.
Example 22. The orthopedic implant of any example herein, particularly any one of examples 20-21, wherein struts of the third zone comprise a plurality of prominences and recesses that increase the third coefficient of friction.
Example 23. The orthopedic implant of any example herein, particularly any one of examples 20-22, wherein: the first zone of the porous structure exhibits a coefficient of friction with cancellous bone tissue of 0.2 to 0.5; the second zone of the porous structure exhibits a coefficient of friction with cancellous bone tissue of 0.4 to 0.6; and the third zone of the porous structure exhibits a coefficient of friction with cancellous bone tissue of 0.7 to 1.1.
Example 24. The orthopedic implant of any example herein, particularly any one of examples 20-23, wherein the first zone, the second zone, and the third zone of the porous structure each extend at least partially around a perimeter of the implant body.
For purposes of this description, certain aspects, advantages, and novel features of the embodiments of this disclosure are described herein. The disclosed methods, apparatus, and systems should not be construed as being limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed embodiments, alone and in various combinations and sub-combinations with one another. The methods, apparatus, and systems are not limited to any specific aspect or feature or combination thereof, nor do the disclosed embodiments require that any one or more specific advantages be present or problems be solved.
Although the operations of some of the disclosed embodiments are described in a particular, sequential order for convenient presentation, it should be understood that this manner of description encompasses rearrangement, unless a particular ordering is required by specific language set forth below. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed methods can be used in conjunction with other methods.
As used in this disclosure and in the claims, the singular forms “a,” “an,” and “the” include the plural forms unless the context clearly dictates otherwise. Additionally, the term “includes” means “comprises.” Further, the terms “coupled” and “associated” generally mean electrically, electromagnetically, and/or physically (e.g., mechanically or chemically) coupled or linked and does not exclude the presence of intermediate elements between the coupled or associated items absent specific contrary language.
In some examples, values, procedures, or apparatus may be referred to as “lowest,” “best,” “minimum,” or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many alternatives can be made, and such selections need not be better, smaller, or otherwise preferable to other selections.
In the description, certain terms may be used such as “up,” “down,” “upper,” “lower,” “horizontal,” “vertical,” “left,” “right,” and the like. These terms are used, where applicable, to provide some clarity of description when dealing with relative relationships. But, these terms are not intended to imply absolute relationships, positions, and/or orientations. For example, with respect to an object, an “upper” surface can become a “lower” surface simply by turning the object over. Nevertheless, it is still the same object.
Unless otherwise indicated, all numbers expressing angles, dimensions, quantities of components, forces, moments, molecular weights, percentages, times, and so forth, as used in the specification or claims are to be understood as being modified by the term “about.” Accordingly, unless otherwise indicated, implicitly or explicitly, the numerical parameters set forth are approximations that can depend on the desired properties sought and/or limits of detection under test conditions/methods familiar to those of ordinary skill in the art. When directly and explicitly distinguishing embodiments from discussed prior art, the embodiment numbers are not approximates unless the word “about” is recited.
Although there are alternatives for various components, parameters, operating conditions, etc., set forth herein, that does not mean that those alternatives are necessarily equivalent and/or perform equally well. Nor does it mean that the alternatives are listed in a preferred order unless stated otherwise.
As used herein, values or terms modified by the term “substantially” mean±10% of the stated value.
In view of the many possible embodiments to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated embodiments are only examples and should not be taken as limiting the scope of the disclosure. Rather, the scope of the disclosure is at least as broad as the following claims and their equivalents. We therefore claim as all that comes within the scope and spirit of these claims.
The present application is a continuation of International Application No. PCT/US2022/024836, filed Apr. 14, 2022, which claims the benefit of U.S. Provisional Application No. 63/175,018, filed on Apr. 14, 2021, each of which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63175018 | Apr 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2022/024836 | Apr 2022 | US |
| Child | 18485626 | US |
