Patent Publication Number: US-2023137504-A1

Title: Dual mobility cup reverse shoulder prosthesis

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Patent Application No. 62/963,752 filed Jan. 21, 2020, and entitled, “Dual-Cup, Reverse Configuration Shoulder Prosthesis,” which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     Musculoskeletal disorders including osteoarthritis, rheumatoid arthritis, rotator cuff tears, and traumatic fractures can be debilitating for patients and their families. The impaired functioning of these systems can be a burden for these patients (e.g., causing pain or creating an inability to successfully complete tasks). In fact, musculoskeletal complaints are a major cause of work-related absence in developed countries. With an aging population and increases in lifestyle factors (e.g., increased obesity and lack of physical activity), musculoskeletal disorders are expected to increase drastically. 
     Shoulder implants are prostheses implanted to alleviate problems associated with shoulder joints, such as pain due to arthritis or other anatomical malformations. Typical total shoulder implants replace the natural glenohumeral interface of the shoulder with an artificial ball and socket joint. For example, a standard anatomical total shoulder arthroplasty involves replacing a patient&#39;s glenoid with a concave plastic component and the patient&#39;s humeral head with a convex metal component. Because typical total shoulder replacements rely heavily on properly functioning rotator cuff muscles, this type of implant does not work well (and is likely to fail) in individuals with severely weak or damaged rotator cuff muscles. 
     As an alternative to the typical total shoulder replacement, the reverse total shoulder arthroplasty (“RTSA”) was developed, which can work well (and minimize failure) in individuals with weak or damaged rotator cuff muscles. In a typical RTSA procedure, the natural glenohumeral interface is removed and is replaced with a convex part on the glenoid side of the shoulder, and concave part on the humeral side of the joint. Although more typical candidates for RTSA are those with cuff tear arthropathy, RTSA has been continually expanded to address various other conditions including severe proximal humeral fractures, glenoid and humeral bone loss, tumors, and failed shoulder arthroplasty (e.g., typically caused by dysfunction of rotator cuff muscles). Thus, the number of patients undergoing RTSA is only expected to increase over the years. For example, in 2011, about 21,692 people underwent reverse total shoulder arthroplasty in just the United States alone. 
     While RTSA procedures have generally been helpful for patients, they can be worse than typical total shoulder implants in some cases. Thus, it would be desirable to have improved systems and methods for reverse total shoulder prostheses. 
     SUMMARY OF THE DISCLOSURE 
     Some embodiments of the disclosure provide a reverse shoulder prosthesis system. The system can include a glenosphere configured to be securable to a scapula of a patient, the glenosphere can have a convex surface, a humeral socket having a concave surface, and a cup positioned between the convex surface of the glenosphere and the concave surface of the humeral socket. The cup can be moveable relative to the glenosphere and to the humeral socket. 
     In some embodiments, the system can include a humeral stem coupled to the humeral socket. The humeral stem can be configured to be secured to and within a humerus of the patient. 
     In some embodiments, the humeral socket is configured to be coupled to a humeral stem of a shoulder prosthesis system that has failed. 
     In some embodiments, the cup has a second concave surface and a second convex surface. The second concave surface of the cup and the convex surface of the glenosphere are configured to contact each other to define a first bearing surface as the cup moves relative to the glenosphere. The second convex surface of the cup and the concave surface of the humeral socket are configured to contact each other to define a second bearing surface as the humeral socket moves relative to the cup. 
     In some embodiments, the second concave surface of the cup has a first radius of curvature, and the second convex surface of the cup has a second radius of curvature. The first radius of curvature of the second concave surface can be smaller than the second radius of curvature of the second convex surface. 
     In some embodiments, the cup has a flange that extends circumferentially around a peripheral edge of the cup. The flange can extend radially away from a central axis of the cup. 
     In some embodiments, the humeral socket is configured to rotate relative to the cup in a first rotational direction until the humeral socket reaches the flange of the cup. 
     In some embodiments, a gap is defined between a surface of the flange and an edge of the humeral socket. In some embodiments, as the humeral socket rotates in a first rotational direction, the gap is minimized until the edge of the humeral socket contacts the surface of the flange. 
     In some embodiments, the flange is configured to prevent an edge of the humeral socket from rotating past an edge of the cup. 
     In some embodiments, when the edge of the humeral socket contacts the surface of the flange, the humeral socket and the flange are configured to prevent the humeral socket from moving further in the first rotational direction relative to the cup. 
     In some embodiments, the cup is configured such that when the edge of the humeral socket contacts the surface of the flange further rotation of the humeral socket in the first rotational direction causes the cup to rotate in the first rotational direction relative to the glenosphere. 
     In some embodiments, the flange includes an exterior concave surface that extends circumferentially around the cup. The concave surface of the humeral socket can have an arcuate lip that extends circumferentially around the humeral socket. The arcuate lip of the humeral socket can be configured to engage the exterior concave surface so that an outer surface of the flange is flush and aligned with an outer surface of the humeral socket. 
     In some embodiments, the system can include a baseplate coupled to the glenosphere. The flange of the cup is configured to prevent a peripheral edge of the humeral socket from contacting the baseplate. The flange of the cup is configured to prevent the peripheral edge of the humeral socket from contacting the glenosphere. 
     In some embodiments, the flange of the cup is configured to prevent the peripheral edge of the humeral socket from extending beyond the baseplate. 
     In some embodiments, the humeral socket is configured to rotate together with the cup, and is configured to rotate relative to the cup. 
     In some embodiments, the system can include a baseplate coupled to the glenosphere. The glenosphere can define a spherical portion that has a geometric center defined at an equator of the spherical portion. A distance between a coupling surface of the baseplate and the geometric center of the spherical portion can be a percentage of a radius of the glenosphere. The percentage can be between 20% and 70% 
     In some embodiments, the system can include a humeral stem coupled to the humeral socket. The humeral stem configured to be receivable within the humerus of the patient. A range of motion of the system can be greater than 60 degrees. The range of motion can be defined between a neutral position of the humeral stem relative to the glenosphere and a maximum rotational position of the humeral stem relative to the glenosphere. In the maximum rotational position, the cup can contact a baseplate or the end of the glenosphere. 
     In some embodiments, in the maximum rotational position a flange of the cup contacts the baseplate or the end of the glenosphere. 
     In some embodiments, the cup has opposing surfaces that are non-concentric. A thickness of the cup defined between the opposing surfaces varies based on an offset between the opposing surfaces. 
     In some embodiments, the system can include a baseplate coupled to the glenosphere. The cup can be configured to rotate relative to the glenosphere until the cup contacts the baseplate. 
     In some embodiments, the glenosphere can include a stem positioned at an end of the glenosphere, and a bore directed through the stem. The system can include a baseplate configured to be secured to a scapula of a patient. The baseplate can be sized to nest within the bore of the glenosphere, and the baseplate can be configured to be coupled to the glenosphere. 
     In some embodiments, the stem is integrally formed with the glenosphere. 
     Some embodiments of the disclosure provide a reverse shoulder prosthesis system. The system can include a glenosphere configured to be securable to a scapula of a patient, the glenosphere having a convex surface, a humeral socket having a concave surface, and a cup positioned between the convex surface of the glenosphere and the concave surface of the humeral socket. The cup can be snap-fitted onto the glenosphere. 
     The foregoing and other aspects and advantages of the present disclosure will appear from the following description. In the description, reference is made to the accompanying drawings that form a part hereof, and in which there is shown by way of illustration one or more exemplary versions. These versions do not necessarily represent the full scope of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following drawings are provided to help illustrate various features of non-limiting examples of the disclosure, and are not intended to limit the scope of the disclosure or exclude alternative implementations. 
         FIG.  1    is a side view of a reverse shoulder prosthesis system in an assembled configuration. 
         FIG.  2 A  shows a front isometric view of a baseplate of the reverse shoulder prosthesis system of  FIG.  1   . 
         FIG.  2 B  shows a front view of the baseplate of  FIG.  2 A . 
         FIG.  3 A  shows an isometric view of an assembly including the baseplate coupled to a glenosphere. 
         FIG.  3 B  shows a front view of the assembly of  FIG.  3 A . 
         FIG.  4 A  shows an isometric view of another glenosphere. 
         FIG.  4 B  shows a side view of the glenosphere of  FIG.  4 A . 
         FIG.  5 A  shows a front isometric view of a cup of the reverse shoulder prosthesis system of  FIG.  1   . 
         FIG.  5 B  shows a front view of the cup of  FIG.  5 A . 
         FIG.  5 C  shows a cross-sectional view of the cup taken along line  5 C- 5 C of  FIG.  5 B . 
         FIG.  6 A  shows a front isometric view of a socket of the reverse shoulder prosthesis system of  FIG.  1   . 
         FIG.  6 B  shows another isometric view of the socket of  FIG.  6 A . 
         FIG.  6 C  shows a cross-sectional view of the socket taken along line  6 C- 6 C of  FIG.  6 A . 
         FIG.  7 A  shows an isometric view of a stem of the reverse shoulder prosthesis system of  FIG.  1   . 
         FIG.  7 B  shows a side view of the stem of  FIG.  7 A . 
         FIG.  7 C  shows a cross-sectional view of the stem taken along line  7 C- 7 C of  FIG.  7 B . 
         FIG.  8    shows an exploded view of the reverse shoulder prosthesis system of  FIG.  1   . 
         FIG.  9    shows the reverse shoulder prosthesis system of  FIG.  8    assembled. 
         FIG.  10 A  shows a cross-sectional view of the reverse shoulder prosthesis system of  FIG.  8    assembled and in one rotational position. 
         FIG.  10 B  shows another cross-sectional view of the reverse shoulder prosthesis system of  FIG.  8    assembled and in a second rotational position, different from the first rotational position. 
         FIG.  11 A  shows a cross-sectional view of the system of  FIG.  1    that has a cup without a flange, in a first rotational position. 
         FIG.  11 B  shows a cross-sectional view of the system of  FIG.  11 A  having the cup without the flange, in a second rotational position different from the first rotational position. 
         FIG.  12 A  shows a cross-sectional view of another glenosphere that has a baseplate coupled to an end of the glenosphere. 
         FIG.  12 B  also shows a cross-sectional view of the glenosphere interfaced with the cup, and coupled to the baseplate, all from the system of  FIG.  1   . 
         FIG.  13    shows a cross-sectional view of the baseplate, the glenosphere, the cup, and the socket, all from the system of  FIG.  1   . 
         FIG.  14    shows a diagram of a causal loop for main parameters in a reverse shoulder prosthesis system. 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENT DISCLOSURE 
     While RTSA procedures can reduce pain and provide relief, complication rates still remain undesirably high. For example, some sources of failure include the failure of the glenosphere (or the baseplate), infection, and dislocation of the humeral socket. However, even in patients without complications, typical RTSA procedures (and corresponding implants) can still present issues. For example, the functional range of motion of typical RTSA implants is significantly less than the functional range of motion of a typical shoulder joint—including a significantly limited internal rotation relative to the axial axis of the patient. 
     Some embodiments of the disclosure provide advantages to these issues (and others) by providing improved systems and methods for reverse total shoulder prostheses. In particular, some embodiments of the disclosure provide a reverse total shoulder implant that can include a glenosphere, a humeral socket, and a dual mobility cup located between the glenosphere and the humeral socket. The dual mobility cup provides advantages over conventional reverse total shoulder implants that include a glenosphere, a stationary liner, and a humeral socket. For example, in a conventional case, in order to increase the range of motion of the implant, the glenosphere is increased in size (radius) and/or center of rotation thereby increasing the articulating surface of the implant. However, by increasing the radius of the glenosphere and/or the center of rotation offset, there is an, increase in undesirable forces on the implant (e.g., increasing torque on the baseplate). 
     Because the dual mobility cup can advantageously articulate with both the glenosphere and the humeral socket, the range of motion for the implant is increased. In other words, the movement of the dual mobility cup with a surface of the glenosphere provides one range of motion for the implant, and the movement of the dual mobility cup with a surface of the humeral socket provides a second range of motion for the implant. These ranges of motion collectively provide an increased range of motion for the implant, which is larger (and more dynamic) than the conventional reverse total shoulder implants. Additionally, to provide a reasonable range of motion, the glenosphere of the conventional reverse total shoulder implant must be larger than the glenosphere of the reverse total shoulder implant of this disclosure. Thus, the smaller glenosphere of the reverse total shoulder implant of this disclosure allows for decreased undesirable stresses on the implant (e.g., a decrease in torque on the implant due to a decrease in the offset between the center of rotation of the glenosphere and the mounting location of the glenosphere). 
       FIG.  1    shows a side view of a reverse shoulder prosthesis system  100  for a reverse total shoulder replacement in an assembled configuration. The system  100  can include a baseplate  102 , a glenosphere  104  coupled to the baseplate  102 , a cup  106 , and a humeral component  108  having a socket  110  and a stem  112 . As shown, one end of the baseplate  102  is coupled to the glenosphere  104 , while an opposing end of the baseplate  102  can be coupled to a bone of a patient (e.g., the glenoid fossa of the scapula). In some cases, the baseplate  102  can be coupled to the bone using fasteners (e.g., screws, bolts, etc.), adhesives (e.g., cements), etc. For example, the fasteners can be inserted through the baseplate  102  and into the bone to mount the baseplate  102  to the bone of the patient. 
     The glenosphere  104  can be coupled to the baseplate  102  in various ways. For example, the glenosphere  104  can be coupled via an adhesive (e.g., cemented) to the baseplate  102 , can be coupled via fasteners to the baseplate  102 , or can be snap-fitted over the baseplate  102  (e.g., when an interior diameter of the glenosphere  104  has a larger diameter than the diameter of the baseplate  102 ). In some embodiments, the baseplate  102  can be nested entirely (or partially) within the glenosphere  104  so that the glenosphere  104  encapsulates the baseplate  102 . In other configurations, the baseplate  102  can be exteriorly located relative to the glenosphere  104 . In some embodiments, the baseplate  102  and the glenosphere  104  can both be formed of a metal (e.g., Titanium alloy, Cobalt Chromium alloy, etc.). 
     In some embodiments, the baseplate  102  and the glenosphere  104  can each include threads so that the glenosphere  104  can be threadingly engaged with the baseplate  102  to couple the glenosphere  104  to the baseplate  102 . For example, in some cases, the peripheral surface of the baseplate  102  can include threads and an interior surface of the glenosphere  104  can include threads. In this way, after the baseplate  102  is secured to the bone of the patient, the glenosphere  104  can be rotated to threadingly engage the baseplate  102  to secure the glenosphere  104  to the baseplate  102 . In some embodiments, the glenosphere  104  can be coupled to the baseplate  102  via a tapered engagement. For example, a taper (e.g., a Morse taper) of the glenosphere  104  and a taper (e.g., a Morse taper) of the baseplate  102  can be engaged together to couple the glenosphere  104  to the baseplate  102 . 
     The glenosphere  104  defines a spherical portion having an exterior surface  114  that is convex, which can interface and articulate with the cup  106 . The spherical portion of the glenosphere  104  also has a geometric center that is defined at the equator of the spherical portion. The distance from this geometric center and a surface of the bone that the baseplate  102  is coupled to (or the vertical surface of the baseplate  102  as shown in the view of  FIG.  1   ) defines a total offset of the glenosphere  104 . As described above, decreasing this offset can be desirable in that the torque and other forces provided to the baseplate  102  is also decreased, which can increase the longevity of the implant and decrease the likelihood of implant failure. 
     As illustrated, the cup  106  is positioned between the glenosphere  104  and the socket  110  of the humeral component  108 , and is configured to move relative to the glenosphere  104  and relative to the socket  110 . For example, the cup  106  has opposing surfaces  116 ,  118 , having opposing concavities. In particular, the surface  116  of the cup  106  is concave, while the surface  118  of the cup  106  is convex. The surface  116  of the cup  106  is an interior surface of the cup  106  that engages with the exterior surface  114  of the glenosphere  104  to provide a bearing surface in which the surface  116  of the cup  106  slides along the exterior surface  114  of the glenosphere  104 . In other words, the surface  116  of the cup  106  articulates with and relative to the exterior surface  114  of the glenosphere  104 . The surface  118  of the cup  106  is an exterior surface of the cup  106  that engages with an inner surface  120  of the socket  110  (e.g., which is concave) to provide a bearing surface in which the surface  118  of the cup  106  slides along the surface  120  of the socket  110  (or the surface  120  of the socket  110  slides along the surface  118 ). In other words, the surface  118  of the cup  106  articulates with and relative to the surface  120  of the socket  110 . 
     In some embodiments, the materials of the reverse shoulder prosthesis system  100  should have the strength to withstand the loads, biocompatibility for implantation inside the body (e.g., by being non-toxic), not cause adverse reactions in the receiving patient (e.g., corroding), and provide adequate wear characteristics for the bearing surfaces. In some cases, regulatory agencies, such as the U.S. Food &amp; Drug Administration, have specified the material options for the components of a typical reverse total shoulder prosthesis. For example, in some configurations, the socket  110  and the stem  112  can be configured as a monolithic piece, or two separate pieces that can be coupled together. In some cases, the cup  106  can be formed out of a polymer (e.g., polyethylene, or more specifically, ultra-high molecular weight polyethylene (“UHMWPE”)). In some configurations, the glenosphere  104  can be formed from a metal, such as a CoCrMo alloy, titanium alloy, or stainless steel, while the baseplate  102  (and fasteners, as appropriate) can also be formed from a metal (e.g., a titanium alloy, or stainless steel alloy). In some cases, some surfaces of the baseplate  102  can have surface modifications (e.g., etching). 
       FIG.  2 A  shows a front isometric view of the baseplate  102 , while  FIG.  2 B  shows a front view of the baseplate  102 . As shown, the shape of the baseplate  102  is circular and defined by a peripheral surface  122 ; however, in alternative configurations, the baseplate  102  can be shaped differently (e.g., square, octagonal, etc.). The baseplate  102  includes holes  124 ,  126 ,  128 ,  130 ,  132  that each extend entirely through the thickness of the baseplate  102  (e.g., from a coupling surface  134  to an opposite mounting surface). Each hole  124 ,  126 ,  128 ,  130 ,  132  is configured to receive a fastener (e.g., a fixation screw) so that the baseplate  102  can be secured to the bone of the patient. In some cases, the peripheral surface that defines each hole can include threading that can engage with a corresponding fastener. As shown, the holes  124 ,  126 ,  128 ,  130  are all substantially (e.g., deviating by less than 20%) identical in size, and the hole  132  can be larger than the holes  124 ,  126 ,  128 ,  130  (e.g., to receive a larger fastener). In some cases, the holes  124 ,  126 ,  128 ,  130 , rather than extending perpendicularly relative to the surface  134  of the baseplate  102 , can extend through the baseplate  102  at an angle relative to the surface  134  other than 90 degrees. 
       FIG.  3 A  shows an isometric view of an assembly including the baseplate  102  coupled to the glenosphere  104 , and  FIG.  3 B  shows a front view of the assembly of  FIG.  3 A . As shown in  FIGS.  3 A and  3 B , the holes of the baseplate  102  have been removed for visual clarity. In this configuration, a flat surface  136  of the glenosphere  104  is coupled to the coupling surface  134  of the baseplate  102  (e.g., with cement) so that the baseplate  102  is exteriorly positioned relative to the glenosphere  104 . 
     In some embodiments, the glenosphere  104  can define a glenosphere center of rotation offset, which can be the height of the truncated section of the sphere that comprises the glenosphere  104 . In other words, the glenosphere center of rotation offset can be defined between an end surface of the truncated end of the glenosphere  104  (e.g., the flat surface  136 ) and the equator of the glenosphere  104 . In some cases, the glenoid center of rotation can be defined as the thickness of the baseplate  102 . In some embodiments, the center of rotation offset of the glenosphere  104  can be defined as the sum of the glenosphere center of rotation offset and the glenoid center of rotation offset (e.g., the thickness of the baseplate  102 ). 
     In some embodiments, a radius of the glenosphere  104  can be in a range between 16 mm and 18 mm. In more specific cases, the radius of the glenosphere  104  can be less than 16 mm, or substantially less than 16 mm (e.g., deviating by 20%). 
       FIG.  4 A  shows an isometric view of another glenosphere  144 , and  FIG.  4 B  shows a side view of the glenosphere  144 . The glenosphere  144  may be a different configuration than a glenosphere  104  described above with respect to  FIGS.  1 - 3 B , but can be implemented with the system  100 . In other words, the glenosphere  144  can replace the glenosphere  104  in the system  100  of  FIG.  1   . Similarly to the glenosphere  104 , the glenosphere  144  also has a spherical portion  146 , but also has a stem  148  extending from the spherical portion  146 , which is cylindrical in shape. As shown, the stem  148  is integrally formed with the spherical portion  146 , however, in alternative configurations the stem  148  can be coupled to the spherical portion  146 . The glenosphere  144  also includes a bore  150  directed through one end of the glenosphere  144 , opposite the end of the spherical portion  146 . In particular, the bore  150  can be defined by a peripheral surface  152 , extending through the entirety of the stem  148 , and in some cases, past the stem  148  and partially into the spherical portion  146 . In some embodiments, the bore  150  extends only partially through the stem  148 . As shown, the bore  150  is cylindrical in shape, however, in other configurations, the bore  150  can have other shapes. The diameter of the bore  150  can be the same (or substantially similar) as the diameter of the baseplate  102  so that, when assembled, the baseplate  102  nests entirely within the bore  150  of the glenosphere  144 . Thus, the diameter (or perimeter) of the stem  148  of the glenosphere  144  can be larger than the diameter (or perimeter) of the baseplate  102 . 
     In some embodiments, the peripheral surface  152  that defines the bore  150  can contact the peripheral surface  122  of the baseplate  102  when the system  100  is assembled. In some configurations, the peripheral surface  152  of the glenosphere  144  can include threads and the peripheral surface  122  of the baseplate  102  can include threads so that the peripheral surface  152  can threadingly engage the peripheral surface  122  of the baseplate  102  to secure the glenosphere  144  to the baseplate  102 . As shown in  FIG.  4 B , the spherical portion  146  defines a geometric center  156  that is located at the equator  158  of the spherical portion  146 . The perpendicular distance  160 , also known as the glenosphere center of rotation offset, as illustrated in  FIG.  4 B  between the equator  158  (or the geometric center  156 ) of the spherical portion and an end of the spherical portion  146  connected to the stem  148  can be a percentage of the radius  162 . In some embodiments, this percentage can in a range that is between a value close to 0% (e.g., 0% exclusive, or within a few percentages of 0%), corresponding to a glenosphere center of rotation offset  160  of slightly larger than 0 mm (e.g., 0 mm exclusive), and a value close to 100% (e.g., 100% exclusive, or within a few percentages of 100%). In some embodiments, this percentage can be in a range between 20% and 70%. In some specific cases, such as when the radius  162  is 16 mm, the glenosphere center of rotation offset  160  can be greater than and close to 4 mm (e.g., 4 mm exclusive, or a few percentages of and above 4 mm). In other specific cases, such as when the radius  162  is 18 mm, the glenosphere center of rotation offset  160  can be lower than and close to 10 mm (e.g., 10 mm exclusive, or a few percentages of and below 10 mm). 
       FIG.  5 A  shows a front isometric view of the cup  106 ,  FIG.  5 B  shows a front view of the cup  106 , and  FIG.  5 C  shows a cross-sectional view of the cup taken along line  5 C- 5 C of  FIG.  5 B . As described above, the cup  106  has opposing surfaces  116 ,  118  which can collectively define a thickness  164  of the cup  106 . Because the surfaces  116 ,  118  have different radii of curvature, the thickness of the cup  106  varies from one side of the cup  106  to another (e.g., with reference to the orientation shown in  FIG.  5 C , the thickness is generally non-uniform increasing from the upper annular portion toward the lower base of the cup  106 ). In other words, the surface  116  has a first radius of curvature that corresponds to the radius of curvature of the glenosphere  104 , while the surface  118  has a second radius of curvature that corresponds to the radius of curvature of the socket  110 . In one embodiment, the opposing surfaces  116 ,  118  of the cup  106  are described as generally non-concentric, such that the thickness of the cup  106  defined at points between the opposing surfaces  116 ,  118  varies based on the offset between the opposing surfaces  116 ,  118  at that point. In some embodiments, and as illustrated, the first radius of curvature of the surface  116  is smaller than the second radius of curvature of the surface  118 . In some configurations, the cup  106  can be snap-fitted on the glenosphere  104  (e.g., the dimensions of the surface  116  of the cup  106  and the surface  114  of the glenosphere  104  enable a snap-fitted engagement between these components), while the socket  110  may not be snap-fitted with the surface  118  of the cup  106 . In some embodiments, the bearing surface between the surface  116  of the cup  106  and the glenosphere  104  can be semi-constrained, while the bearing surface between the surface  118  of the cup  106  and the surface  120  of the socket  110  can be non-constrained. Thus, the bearing interface between the surface  118  of the cup  106  and the surface  120  of the socket  110  can slide more easily than the bearing surface between the surface  116  of the cup  106  and the glenosphere  104 . 
     In some embodiments, as shown in  FIGS.  5 A- 5 C , the cup  106  can include a flange  166  that extends circumferentially around a peripheral edge of the cup  106 , and that extends radially away from a central axis  168  of the cup  106 . In some cases, and as illustrated, the flange  166  extends circumferentially around the entire axis  168 . In other cases, the flange  166  can extend partially around the entire axis  168 , in a discontinuous manner around the axis  168  (e.g., the flange  166  having one or more gaps at points around the axis  168 ). In some embodiments, the flange  166  can define a concave exterior surface  170  that also extends circumferentially around the cup  106  (e.g., around the entire axis  168 ). 
     In some embodiments, the cup  106  can define a cup center offset  167  (or, in other words, shift), which can be the offset between the geometric centers of rotation of the inner surface  116  and the outer surface  118  of the cup  106  (e.g., because the surface  116 ,  118  are non-concentric). In some embodiments, the cup  106  can define a cup depth of coverage  173 , which can be the distance between an entrance plane  171  of the cup  106  and the center of the inner surface  116 . 
       FIG.  6 A  shows a front isometric view of the socket  110 ,  FIG.  6 B  shows another isometric view of the socket  110 , and  FIG.  6 C  shows a cross-sectional view of the socket  110  taken along line  6 C- 6 C of  FIG.  6 A . Along with the surface  120  that is an interior concave surface, the socket  110  can also include an exterior convex surface  172 , a lip  174  that extends circumferentially around the entire socket  110 , and protrusions  176 ,  178 . The lip  174  can have an arcuate convex surface  180  that also extends circumferentially around the entire socket  110 , and which can be flush with the surface  120  of the socket  110 . As shown, the protrusion  176  extends downwardly from a flat surface  182  that is located on an opposing end of the socket  110  away from the lip  174 , along a central axis  184  of the socket  110  that bisects opposing sides of the socket  110 . The protrusion  178  also extends downwardly from the flat surface  182  and is positioned laterally of the protrusion  176 . Although the protrusions  176 ,  178  are illustrated as having a frustoconical shape, in other configurations, the protrusions  176 ,  178  can have other shapes. Additionally, although the protrusion  176  is illustrated as being longer and having a larger diameter than the protrusion  176 , in other configurations, the protrusions  176 ,  178  can have different diameters and lengths. 
     In some embodiments, the protrusions  176 ,  178  have tapered surfaces. For example, as illustrated, the protrusion  176  has tapered surfaces  186 ,  188 , while the protrusion  178  has tapered surfaces  190 ,  192 . In particular, the tapered surface  186  is situated at an interface between an end of the protrusion  176  and the flat surface  182 , and the tapered surface  188  is situated at a free end of the protrusion  176 . Similarly, the tapered surface  190  is situated at an interface between an end of the protrusion  178  and the flat surface  182 , and the tapered surface  192  is situated at a free end of the protrusion  178 . The tapered surfaces  186 ,  188 ,  190 ,  192  can provide an interface that allows the protrusions  176 ,  178  to be coupled to the humeral stem  112  (or a different humeral stem, such as an existing humeral stem of a total shoulder replacement system that has failed). In some cases, the tapered surfaces  186 ,  188 ,  190 ,  192  can be Morse tapers. In some embodiments, the tapered surfaces  186 ,  188 ,  190 ,  192  can be tapered at the same angle, or in other cases, can each be tapered at different angles. 
       FIGS.  7 A and  7 B  each show different views of the stem  112 , while  FIG.  7 C  shows a cross-sectional view of the stem  112  taken along line  7 C- 7 C of  FIG.  7 B . The stem  112  can include a neck  195 , an arm  197  coupled to and extending from the neck  195 , and bores  196 ,  198 . The neck  195  can have an end surface  200  that is angled relative to a length of the arm  197  that extends from the neck  195  in a straight manner (e.g., the surface  200  is flat and forms an angle with the length of the arm  197  indicated in  FIG.  7 B  as the angle θ). In some embodiments, the end surface  200  contacts the flat surface  182  of the socket  110  when the socket  110  is coupled to the stem  112 . In some cases, a smaller humeral neck-shaft angle (e.g., angle θ when the socket  110  is coupled to the stem  112 ) contributes to a reduction in adduction deficit. Each of the bores  196 ,  198  are directed through and extend past the end surface  200  of the neck  195 , and correspond respectively to the shape of the protrusions  176 ,  178  of the socket  110 . For example, the bores  196 ,  198  are illustrated as also being frustoconical to match the protrusions  176 ,  178 , however, the bores  196 ,  198  can be shaped differently if the protrusions  176 ,  178  are shaped differently. 
     As shown in  FIG.  7 C , an end of the bore  196  (opposite its open end) has a tapered surface  202  that extends circumferentially around the entire bore  196 , and an end of the bore  198  (opposite its open end) has a tapered surface  204  that extends circumferentially around the entire bore  196 . When the socket  110  is coupled to the humeral stem  112 , the protrusion  176  is inserted into the bore  196  and the tapered surface  188  of the protrusion  176  engages with the tapered surface  202  of the bore  196  to secure the protrusion  176  within the bore  196 . Similarly, when the socket  110  is coupled to the humeral stem  112 , the protrusion  178  is inserted into the bore  198  and the tapered surface  192  of the protrusion  178  engages with the tapered surface  204  of the bore  198  to secure the protrusion  178  within the bore  198 . Although not shown, opposing ends of the bores  196 ,  198  can also have tapered surfaces that each engage with the respective tapered surfaces  186 ,  190  of the corresponding protrusions  176 ,  178 . 
     In some embodiments, as shown in  FIG.  7 A , the arm  197  of the stem  112  can have slots  206 , each of which can be situated between tapered surfaces  208  of the arm  195  (e.g., the tapered surface  208  being tapered along the length of the arm  195  until reaching a tip  210  of the arm  195 ). The arm  197  is configured to be inserted into the humeral canal of the humerus of the patient to secure the stem  112 . In some cases, the arm  197  can be dimensioned so that the arm  197  can be secured within the humeral canal without the use of adhesives (e.g., cement). For example, the surfaces of the arm  197  can engage the inner surfaces of the humeral canal to provide an interference fit. In other cases, the arm  197  can be cemented within the humeral canal with an adhesive. 
     In the illustrated embodiment, the stem  112  includes holes  212 ,  214  that are directed through a bridge  217  located between recesses  216 ,  218 . The holes  212 ,  214  are illustrated as having the same size and shape (e.g., being circular), however the holes  212 ,  214  can take on other shapes. In some cases, the holes  212 ,  214  can each provide a mounting location for sutures. For example, sutures can be inserted through a respective hole  212 ,  214  inserted into a soft tissue structure, and tied at the respective hole  212 ,  214  to secure the soft tissue structure to the neck  195  of the stem  112 . In some cases, the holes  212 ,  214  can be used for suturing the stem  112  with fractured humerus bone tissue, or when seen necessary for better positioning and stability of the stem  112 . In some embodiments, a surface  220  extending between the surface  200  and the arm  197  can have a radius of curvature that can be adjusted based on desired design parameters of the stem  112 . 
     In some embodiments, a bore  201  can be directed through a top surface of the neck  195  of stem  112 . The bore  201  can be dimensioned and shaped to receive a tool (e.g., a post), which can provide an interface for directing the stem  112  into the patient&#39;s humerus, without potentially damaging the stem  112 . For example, with the tool in mating engagement with the bore  201 , a hammer (or other tool) can strike the tool to advance the stem  112  into the humerus of the patient without contacting the stem  112  with the hammer. In other embodiments, the bore  201  can be threaded to threadingly engage a tool that can be pulled to retreat the stem  112  out of the humerus (e.g., to more easily remove the implant, if the implant has failed). 
     In some embodiments, when the socket  110  is coupled to the stem  112 , via the protrusions  176 ,  178  and corresponding bores  196 ,  198 , the socket  110  (more specifically, the flat surface  182 ) is oriented and aligns with the angle θ (e.g., the angle that the surface  200  is oriented along). Additionally, in some cases, the protrusions  176 ,  178  (or other coupling components) of the socket  110  provide a modularity feature that allows the socket  110  to be fixed on stems of an anatomical total shoulder replacement (e.g., during the revision of a failed anatomical total shoulder replacement (“TSA”)). In this way, if an anatomical total shoulder arthroplasty fails, the humeral stem from the failed total shoulder arthroplasty implant system can be utilized, and thus prevents the removal of this stem (e.g., which may decrease surgical complications, and quicken the surgical process of the reverse shoulder implant). In some embodiments, the socket  110  can be coupled to the stem  112  (or other stems, such as of a failed anatomical total shoulder arthroplasty implant system) in other ways, such as mechanical fasteners, adhesives (e.g., cement), etc. 
     In some embodiments, although not shown, the socket  110  can include a spacer (not shown) between the base of the socket  110  (e.g., between the flat surface  182  of the socket  110 ) and the end surface of the stem  112  (e.g., the surface  200  of the stem  112 ) to lengthen the humerus (e.g., when a smaller stem is preferred). This can provide a desirable surgical option during a reverse shoulder arthroplasty procedure. For example, the spacer can lengthen the humeral stem, and can add more lateralization for the socket  110  (e.g., when the socket  110  is coupled to the stem  112 ). In some embodiments, the spacer, when placed, can engage with the protrusions  176 ,  178  of the socket  110 , and the spacer can engage with the bores  196 ,  198  of the stem  112  so that the socket  110  is indirectly engaged with the socket  112 . In other cases, the protrusions  176 ,  178  can be made longer in length (than as illustrated) so that when a spacer is placed between the socket  110  and the stem  112 , the protrusions  176 ,  178  are still able to properly engage the bores  198 ,  196  of the stem  112 . 
       FIG.  8    shows an exploded view of the reverse shoulder prosthesis system  100 , showing relative orientations of the glenosphere  104 , the cup  106 , the socket  110 , and the stem  112 . As shown, the baseplate  102  is coupled to the glenosphere  104 , the cup  106  is engaged with the glenosphere  104  (e.g., snap-fitted), the socket  110  is coupled to the stem  112  (e.g., by seating the protrusion  176  within the bore  196  and the protrusion  178  within the bore  198 , although other coupling configurations can be used such as fasteners), and the socket  110  is engaged with the cup  106 . 
       FIG.  9    shows the reverse shoulder prosthesis system  100  assembled, demonstrating how the components move to provide a larger range of motion (e.g., which can be defined from an end of the stem  112  relative to the baseplate  102 ) compared to conventional systems. For example, as shown in  FIG.  9   , the cup  106  articulates with both the glenosphere  104  and the socket  110  to provide an increased total range of motion of the system  100  (e.g., the scapulohumeral range of motion during abduction). In some embodiments, the cup  106  also provides a more dynamic adjustment of positions as compared to a typical reverse total shoulder implant. For example, in the typical reverse total shoulder implant, the entire mobility lies on the interface between the glenosphere and the humeral socket, as no cup is provided between the components. However, in the reverse should prosthesis system  100  described herein, the system  100  has two bearing surfaces, with one bearing surface between the glenosphere  104  and the cup  106 , and with a second bearing surface between the cup  106  and the socket  110 . Not only does this provide an increased range of motion, but this also provides a more dynamic adjustment of positions. 
     In some embodiments, a healthy shoulder abduction involves the motion of humerus and scapula approximately in the ratio of 2:1 (e.g., the glenohumeral versus the scapulothoracic). That is, for every two degrees of abduction by the humerus (indicated as ROM 2  on  FIG.  9   ), the scapula moves by one degree (indicated as ROM 1  on  FIG.  9   ). Typically, however, standard reverse shoulder designs have a ratio that is closer to 1:1, which leads to an average total abduction range of motion (“ROM”) of 120 degrees (e.g., with 60 degrees from the scapula and another 60 degrees from the prosthesis). The reverse shoulder prosthesis system  100  with the cup  106  can provide an increased range of motion of the implant that exceeds these values to increase the total abduction range of motion (indicated as ROM on  FIG.  9   ). For example, the range of motion of the system (e.g., ROM 2 ) can be larger than 60 degrees, and the ratio of the range of motion of the humerus to the range of motion of the scapula can be larger than 1:1. In some cases, the ratio of the range of motion of the humerus to the range of motion of the scapula for the system can be substantially (e.g., ±20%) close to the 2:1 ratio. 
       FIGS.  10 A and  10 B  show cross-sectional views of the reverse shoulder prosthesis system  100  assembled and in two different rotational positions. In some embodiments, as the stem  112  is rotated in a first rotational direction  222  (e.g., by the patient moving their arm), the socket  110  moves relative to the cup  106  and the cup  106  moves relative to the glenosphere  104 . In some embodiments, the movement between the socket  110  and the cup  106  occurs simultaneously with the movement between the cup  106  and the glenosphere  104 , which can provide enhanced dynamics of the system  100  as opposed to previous reverse shoulder implants (e.g., the system  100  can absorb forces from movement of the stem  112  and translate them into movement of the cup  106  and the socket  110 , providing less undesirable forces to the system  100 ). As the stem  112  is continually rotated in the first rotational direction  222 , a gap between the lip  174  and the flange  166  decreases until the lip  174  of the socket  110  contacts and interfaces with the flange  166  of the cup  106 . At this point, when the lip  174  of the socket  110  contacts the flange  166 , further relative rotation between the socket  110  and the cup  106  is prevented. Rather, when the lip  174  contacts the flange  166  the socket  110  and the cup  106  rotate together (e.g., along the first rotational direction  222 ).  FIG.  10 A  in particular shows when the lip  174  contacts the flange  166 , and in particular shows the arcuate convex surface  180  of the lip  174  seating with the concave surface  170  of the flange  166 . Additionally, and as illustrated, when the lip  174  contacts the flange  166 , the exterior surface  172  of the socket  110  is flush and aligns with the exterior surface  226  of the flange  166 . 
       FIG.  10 B  specifically shows the system  100  at a humeral range of motion limit for the stem  112 , which in this case is a maximum abduction position of the stem  112 . From the position of the system  100  illustrated in  FIG.  10 A , the stem  112  is further rotated in the first rotational direction  222  until the cup  106  contacts the baseplate  102 . At this point, because the flange  166  of the cup  106  prevents further advancement of the socket  110  along the first rotational direction  222 , the socket  110  is situated away from and does not contact either the baseplate  102  or the bone that the baseplate  102  is secured to (e.g., the scapula). Thus, the flange  166  of the cup  106  can prevent the socket  110  from contacting the bone that the baseplate  102  is connected to, or the baseplate  102  (e.g., minimizing or preventing impingement of the implant with surrounding bone tissue at a maximum range of motion, such as the maximum abduction position). In other words, the flange  166  of the cup  106  prevents the socket  110  from advancing past the flange  166  and thus prevents the socket  110  from advancing past the baseplate  102  and contacting the bone. While the dynamics of rotation described herein are made with simplified reference to the two-dimensional representation of, for instance,  FIGS.  10 A and  10 B , the rotational dynamics provide for relative rotation in multiple directions (e.g., three degrees of freedom, including combinations of pitch, yaw, and roll). 
     In some embodiments, the flange  166  of the cup  106  can also prevent contact between the socket  110  and the glenosphere  104 . For example, beginning at the position of the system  100  illustrated in  FIG.  10 A , if the flange  166  of the cup  106  were removed and the stem  112  rotated in the first rotational direction  222 , only the socket  110  may rotate (or may rotate past the cup  106 ). In this case, the interior surface  120  of the socket  110  may contact the glenosphere  104 , which can cause a degrading of these surfaces that can, over time, cause components of the system  100  to not move as intended. Additionally, because the socket  110  and the glenosphere  104  can both be formed of metal, the contact between the two can create undesirable metal on metal interface (e.g., which can potentially undesirably discharge metal ions that can be toxic or that can damage surrounding tissue or entire systems). 
     More specifically,  FIGS.  11 A and  11 B  show cross-sectional view of the system  100  that has a cup  106  without the flange  166 .  FIG.  11 A  shows the system in a maximum abduction position, where the socket  110  is in contact with the baseplate  102  and extends past the baseplate  102  to be in contact with the bone that the baseplate  102  is secured to (not shown). The flange  166  can mitigate this issue by ensuring that the socket  110  does not extend beyond the flange  166 , thereby inhibiting impingement of the implant with the bone. Additionally,  FIG.  11 B  shows the system rotated in the first rotational direction  222 , with the socket  110  extending past a peripheral edge of the cup  106  to contact the glenosphere  104 . The flange  166  can ensure that the cup  106  moves with the socket  110  as the socket  110  engages with the flange  166  during shoulder movement, preventing such contact between the socket  110  and the glenosphere  104 . 
       FIG.  12 A  shows a cross-sectional view of another glenosphere  105 , including a baseplate  103  coupled to an end of the glenosphere  105 . In some embodiments, the glenosphere  105  can define a glenosphere center of rotation  107  defined between an end surface of the truncated end of the glenosphere  105  and an equator  109  of the glenosphere  105 , and the thickness of the baseplate  103  can define a center of rotation offset shift  111 . The sum of the glenosphere center of rotation  107  and the center of rotation offset shift  111  can define the center of rotation offset  113  of the glenosphere  105 .  FIG.  12 B  also shows a cross-sectional view of the glenosphere  104  interfaced with the cup  106 , and coupled to the baseplate  102 . Similar to the glenosphere  105  of  FIG.  12 A , an end surface of the baseplate  102  and the equator of the glenosphere  104  can define a COR offset shift of the glenosphere  104  (e.g., the sum between the glenosphere center of rotation and the center of rotation offset shift provided by the baseplate  102 ). In some cases, commercially available reverse shoulder systems lateralize their designs by increasing the COR offset of the glenosphere (e.g., by increasing the size of the glenosphere). However, too much lateralization increases the stress on the baseplate-glenoid interface. The non-concentric design of the cup  106  (e.g., the inner surface  116  and the outer surface  118  being non-concentric) creates a lateral shift in the center of rotation for the socket  110  while minimizing (and preferably without adding) additional stress on the baseplate. 
     Additionally, as described above, increasing the center of rotation offset has advantages (e.g., increased range of motion) and disadvantages (e.g., increased stresses on the fixation location on the bone), which creates a trade-off. However, the inclusion of the cup  106  largely eliminates this trade-off. For example, both systems of  FIG.  12 A and  12 B  have a similar range of motion. However, the first COR of the first system of  FIG.  12 A  is larger than the second COR of the second system of  FIG.  12 B . Thus, with the inclusion of the cup  106  to provide a greater range of motion, the glenosphere  104  can be made smaller to minimize COR offset. 
       FIG.  13    shows a cross-sectional view of the baseplate  102 , the glenosphere  104 , the cup  106 , and the socket  110 . As shown, the socket  110  has a depth (D 1 ) defined between the minima of the surface  120  and a peripheral edge of the socket  110  (e.g., an end of the lip  174 ), while the cup  106  has a depth (d 2 ) defined between the minima of the surface  116  and a peripheral edge of the cup  106  (e.g., an end of the flange  166 ). As also shown, the glenosphere  104  has a radius (R 2 ), and the exterior surface  118  of the cup  106  also has a radius (R 1 ). In some embodiments, the socket  110  can be designed to have the depth (D 1 ) that is based on a specified D 1 /R 1  ratio, which corresponds to the depth dl over the radius of the cup contacting surface (i.e., R 1 ). This creates a semi-constrained interface between the cup  106  and the socket  110 . The d 1 /R 1  ratio of the socket  110  can determine the degree of stability and the range of motion of the shoulder joint. In some cases, the D 1 /R 1  ratio can be about (e.g., ±40 percent) or exactly equal to 0.45. In other cases, the D 1 /R 1  ratio can be substantially 0.45. The glenosphere  104  can also be designed to have radius R 2 , and the cup  106  can have a depth (i.e., D 2 ) that can both result in a specific D 2 /R 2  ratio. In some embodiments, this D 2 /R 2  ratio can create a constrained interface between the glenosphere  104  and the cup  106 . 
     EXAMPLES 
     The following examples have been presented in order to further illustrate aspects of the disclosure, and are not meant to limit the scope of the disclosure in any way. The examples below are intended to be examples of the present disclosure and these (and other aspects of the disclosure) are not to be bounded by theory. For example, the specific dimensions of any particular implementation of the concepts described in connection with the example reverse shoulder prosthesis system  100  may be tailored to the anatomy of any particular patient. 
     In some embodiments, the specifications detailed herein cover a shoulder prosthesis for reverse shoulder arthroplasty. Some goals of the reverse shoulder implant described herein are to improve the functional outcome of currently available implants. For example, this system aims to increase the range of motion of the joint, mitigate the risk of joint dislocation by increasing stability, and reduce scapular bone impingement. 
     In some embodiments, a larger contact surface area for the socket is desirable for scapular impingement reduction and better external/internal rotation, while a smaller glenosphere is desirable to achieve a better fixation on the glenoid fossa during surgery. Commercially available glenospheres can either focus on improving fixation by having smaller sizes, or reducing scapular impingement by having larger glenospheres. The dual mobility cup liner described herein eliminates the tradeoff between impingement and fixation through its design by combining both benefits. 
     The outer surface of the dual mobility cup liner can have a diameter that matches the size of commercially available glenospheres. However, in some cases, due to the increased range of motion provided by the dual mobility cup, the glenosphere can even be made smaller in size. In this way, the smaller glenosphere can be attached to the glenoid fossa of the patient through its baseplate, while still maintaining a larger contact surface for the socket. 
     In some embodiments, the stability of the replaced joint can be increased by tensioning the deltoid muscle. While commercially available reverse shoulder implants can implement this by having an additional spacer component, the non-concentricity of the dual mobility cup liner inherently contributes to lengthening the humerus and thereby tensioning the deltoid. 
     In some embodiments, the system described herein can increase joint range of motion by adding to the overall COR offset through the non-concentricity of the dual cup, and can increase the arc of contact of a smaller glenosphere. Abduction impingement caused by larger glenospheres of commercially available implants can also be reduced (e.g., due to the use of smaller glenosphere for this design), which can provide an increase in the impingement free range of motion. 
     In some embodiments, complex relationships between the design parameters, biomechanics, surgical procedures, and the outcomes for a reverse shoulder prosthesis system are to be considered. While all the design parameters may not have equal weight of contribution to the outcomes, it is worth looking at the effects. Range of motion, adduction deficit, and stability are some of the outcomes to consider. 
       FIG.  14    shows a diagram of a causal loop for main parameters in a reverse shoulder prosthesis system. In some cases, an increase in the lateralization of the glenoid system increases the range of motion of the implant and decreases the adduction deficit. This is usually achieved by increasing the COR offset of the glenosphere, which facilitates a larger arc of contact for the socket. The increase in COR offset also increases external rotation. However, this increase in the offset increases torque on the baseplate, which over time, increases the probability of fractures at the baseplate-glenoid bone interface. In some cases, this probability can be reduced by inferiorly tilting the baseplate during reverse shoulder arthroplasty procedure. 
     In some cases, an increase in the glenosphere diameter contributes to an increase in the arc of contact for the socket, thereby increasing the range of motion, and decreasing the adduction deficit. This case is applicable when the depth of the socket is constant. However, the increase in glenosphere diameter decreases the passive internal rotation and also makes it challenging for fixation during surgery. 
     In some cases, another factor governing the increase in impingement free range of motion and decrease in adduction deficit is the decrease in the humeral stem neck-shaft angle. It is also possible to achieve a decrease in the adduction deficit by lateralizing the humerus with the use of a spacer, thus reducing scapular impingement. 
     In some cases, lateralizing the humerus increases the compressive force of the deltoid muscle, which in turn increases the stability of the joint. The compressive force of the deltoid muscle can be increased by elongating the muscle through inferior glenosphere placement during the surgery. Some studies have shown that placing the glenoid system of the reverse shoulder implant inferiorly contributes to the increase in the range of motion. Increasing stability can also be accomplished by an increase in the d/R ratio, however, this will result in a reduction in the range of motion. 
     The dual mobility cup liner component, as described herein, increases the COR offset without changing the COR offset of the glenosphere, at least maintains the same arc of contact as that of commercial glenospheres while decreasing the size of the glenosphere, and lateralizes the humeral component and increases stability through deltoid tensioning. 
     The present disclosure has described one or more preferred embodiments, and it should be appreciated that many equivalents, alternatives, variations, and modifications, aside from those expressly stated, are possible and within the scope of the invention. 
     It is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the accompanying description or illustrated in the accompanying drawings. Given the benefits of this disclosure, one skilled in the art will appreciate that the disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
     As used herein, unless otherwise limited or defined, discussion of particular directions is provided by example only, with regard to particular embodiments or relevant illustrations. For example, discussion of “top,” “front,” or “back” features is generally intended as a description only of the orientation of such features relative to a reference frame of a particular example or illustration. Correspondingly, for example, a “top” feature may sometimes be disposed below a “bottom” feature (and so on), in some arrangements or embodiments. Further, references to particular rotational or other movements (e.g., counterclockwise rotation) is generally intended as a description only of movement relative to a reference frame of a particular example of illustration. 
     In some implementations, devices or systems disclosed herein can be utilized or installed using methods embodying aspects of the disclosure. Correspondingly, description herein of particular features, capabilities, or intended purposes of a device or system is generally intended to inherently include disclosure of a method of using such features for the intended purposes, a method of implementing such capabilities, and a method of installing disclosed (or otherwise known) components to support these purposes or capabilities. Similarly, unless otherwise indicated or limited, discussion herein of any method of manufacturing or using a particular device or system, including installing the device or system, is intended to inherently include disclosure, as embodiments of the disclosure, of the utilized features and implemented capabilities of such device or system. 
     As used herein, unless otherwise defined or limited, ordinal numbers are used herein for convenience of reference based generally on the order in which particular components are presented for the relevant part of the disclosure. In this regard, for example, designations such as “first,” “second,” etc., generally indicate only the order in which the relevant component is introduced for discussion and generally do not indicate or require a particular spatial arrangement, functional or structural primacy or order. 
     As used herein, unless otherwise defined or limited, directional terms are used for convenience of reference for discussion of particular figures or examples. For example, references to downward (or other) directions or top (or other) positions may be used to discuss aspects of a particular example or figure, but do not necessarily require similar orientation or geometry in all installations or configurations. 
     This discussion is presented to enable a person skilled in the art to make and use embodiments of the disclosure. Given the benefit of this disclosure, various modifications to the illustrated examples will be readily apparent to those skilled in the art, and the generic principles herein can be applied to other examples and applications without departing from the principles disclosed herein. Thus, embodiments of the disclosure are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein and the claims below. The detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected examples and are not intended to limit the scope of the disclosure. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of the disclosure. 
     Various features and advantages of the disclosure are set forth in the following claims.