Abstract:
Disclosed is a system for engaging a prosthesis and for implanting the same. The system can include a component or plurality of components to engage an acetabular prosthesis in both rotational and axial fixation. A method of using the insertion assembly is also disclosed. In addition, a method of assembling, disassembling, and cleaning the insertion assembly is disclosed.

Description:
FIELD 
     The subject disclosure relates to an instrument and method for positioning a prosthesis, and particularly to a method and apparatus for engaging and disengaging from an acetabular prosthesis. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     In performing a procedure on a patient, a prosthesis can be used to replace or augment a natural anatomical feature. For example, due to age, injury, disease, or other causes, a portion of the anatomy may need to be replaced or resurfaced. Examples include replacing an acetabulum on a patient either in conjunction with or separate from replacing or resurfacing a femoral head. An acetabular prosthesis is generally positioned within a prepared acetabulum. 
     Positioning an acetabular prosthesis within a prepared acetabulum can include various dexterous movements. The acetabular prosthesis is generally positioned within the acetabulum in a selected alignment and position. The alignment of the acetabular prosthesis can include rotational positioning that is generally selected to be relative to the natural anatomy. The prosthesis includes a central axis that must be aligned and positioned or is selected to be aligned and positioned with a portion of the natural anatomy. In positioning the acetabular prosthesis in the selected position, both position and axial alignment can be selected. 
     When positioning, the acetabular prosthesis also needs to be engaged into the acetabulum with a selected force to ensure proper seating and positioning of the acetabular prosthesis. Accordingly, positioning the acetabular prosthesis generally requires dexterity on the part of the user, such as a surgeon, to position the acetabular prosthesis appropriately in a patient&#39;s anatomy. Then a force is applied to assist in fixing the prosthesis in the pelvis. 
     SUMMARY 
     An instrument can include a threaded rod that can engage a prosthesis, such as an acetabular prosthesis. The threaded rod can be positioned inside of a through-bore in a handle member and engage a portion of the handle member to allow the acetabular prosthesis to be brought into contact with the handle member. Interconnection of the handle member and the threaded rod can hold the prosthesis both linearly and rotationally relative to an insertion assembly for positioning an acetabular prosthesis with adaptation. In other words, the connection of the threaded rod, the prosthesis, and the handle member can hold the prosthesis from axial movement relative to the handle member. Further, the prosthesis can be rotationally fixed relative to the handle member. 
     In a method of using the instrument, the threaded rod can engage the acetabular prosthesis at a first end and a second end can be received within the handle member to engage a mechanism therein to fix or move the rod assembly and the connected prosthesis into contact with the handle assembly. The interconnected prosthesis and handle assembly can then be used to position the prosthesis into a prepared acetabulum. The method can then reverse to allow for disconnection of the acetabular prosthesis by disengaging the threaded rod from the acetabular prosthesis and then disassembling the threaded rod from the handle. A procedure can then be completed by implanting additional components, such as a femoral component or a liner, and closing a patient. 
     A system to implant a prosthesis into a subject is disclosed, according to various embodiments. The system can include a handle member extending from a first end to a second end and defining a through-bore through at least a portion of the handle member and a threaded member extending from a first end to a second end, the threaded member having threads formed at the first end to threadably engage the prosthesis and a slotted region at the second end. A projection can be provided to extend into the through-bore formed in the handle member to engage the slotted region to hold the threaded member in the handle member. The slotted region includes a first portion and a second portion separate from the first portion that includes a complete groove extending about the threaded member. 
     According to various embodiments, a system to implant a prosthesis into a subject is disclosed. The system can include a handle member extending from a first end to a second end and defining a through-bore through at least a portion of the handle member; and a threaded member extending from a first end to a second end. The threaded member can include a thread formed at the first end to threadably engage the prosthesis. The threaded member can further include a slotted region at the second end including a first portion that is discontinuous about the threaded member formed by at least a first slot wall and a second slot wall, wherein a first opening is formed through a first slot wall and a second opening through the second slot wall with a short groove defined between the first slot wall and the second slot wall extending a part of a distance around the threaded member between the first opening and the second opening and a second portion that includes a long groove extending completely about the threaded member. The system can also include a projection member extending into the through-bore formed in the handle member to engage the slotted region to hold the threaded member in the handle member. The projection is operable to engage both the first portion that is discontinuous to limit a rotation of the threaded member within the handle member and the second portion that includes the long groove to allow a complete rotation of the threaded member within the handle member. 
     According to various embodiments, a method of implanting a prosthesis into a subject is disclosed. The method can include providing a handle member extending from a first handle end to a second handle end and having a through-bore through at least a portion of the handle member and providing a threaded member extending from a first threaded member end to a slotted region at a second threaded member end for positioning into the through-bore. The threaded member can include a thread formed at the first threaded member end to threadably engage the prosthesis. The threaded member can further include a slotted region at the second threaded member end including a first portion that is discontinuous about the threaded member formed by at least a first slot wall and a second slot wall, wherein a first opening is formed through the first slot wall and a second opening is formed through the second slot wall with a short groove defined between the first slot wall and the second slot wall extending at least a part of a distance around the threaded member between the first opening and the second opening and a second portion that includes a long groove extending completely about the threaded member. The method can further include providing a projection member extending into the through-bore to engage the slotted region to hold the threaded member in the handle member. The projection can be operable to engage the first portion direct movement of the threaded member within the handle member and engage the second portion that includes the long groove to allow a complete rotation of the threaded member within the handle member. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  is an exploded view of an insertion assembly, accordingly to various embodiments; 
         FIG. 2  is a detailed cross-sectional view of the handle member of the insert assembly according to  FIG. 1 ; 
         FIG. 3  is a detailed cross-sectional view of a different prospective of the handle member of the insertion assembly of  FIG. 1 ; 
         FIG. 4A  is a detailed perspective view of a slotted portion of the threaded rod of the insertion assembly according to  FIG. 1 ; 
         FIG. 4B  is an alternative perspective view of the slotted end of the threaded rod of the insertion assembly according to  FIG. 1 ; 
         FIG. 5  is a cross-sectional perspective view of the insertion assembly of  FIG. 1 ; 
         FIG. 6  is a detailed perspective phantom view of the insertion assembly of  FIG. 1 ; 
         FIG. 7  is a detailed cross-sectional view of the insertion assembly of  FIG. 1 ; 
         FIG. 8  is an environmental view of the insertion assembly and an attached acetabular prosthesis; 
         FIG. 9A  is a perspective view of a portion of an insertion assembly according to various embodiments; 
         FIG. 9B  is a perspective view of a portion of an insertion assembly according to various embodiments; and 
         FIG. 10  is a detailed cross-sectional view of the insertion assembly of  FIG. 9 . 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully with reference to the accompanying drawings. 
     With reference to  FIGS. 1 ,  2 ,  3 ,  4 A, and  4 B, an inserter assembly  20  is illustrated. The inserter assembly  20  can generally include a handle or graspable member  22  including a graspable portion  24  near a first end and a prosthesis engaging region  26  at a second end. Generally, the prosthesis engaging end  26  can include a selected or keyed shape to assist in resisting rotation of a prosthesis relative to the graspable member  22 , as discussed further herein. The keyed shape can include generally non-circular shapes, such as a square or other shape with at least one flat side. 
     The insertion assembly  20  also includes a threaded rod member  30  that extends from a first end  32  to a second end  34 . The second end  34  can include an external thread  36  that can engage a prosthesis, such as an acetabular prosthesis  40 , in an internally threaded bore  42 . The threaded bore  42  can include a through-bore or a blind bore formed into the acetabular prosthesis  40 . Additionally, the threaded rod  30  can engage an internal surface of the acetabular prosthesis  40  to allow for manipulation of the acetabular prosthesis  40 , particularly when the threaded rod  30  is assembled into the graspable or handle member  22 , as discussed further herein. The acetabular prosthesis  40  can further include a depression or portion to engage the keyed shape of the handle member  22 . Also, it is understood, that any other appropriate prosthesis or member can engage the handle member; other examples include a femoral prosthesis or a humeral prostheses. Also, non-medical members can be engaged, such as a machine part that is to be held relative to an tool for assembly or use. 
     The handle member  22  can further include an impaction end or portion  50  that can be impacted with a mallet  52  or other appropriate surgical impaction tool. As discussed further herein, the prosthesis  40  can be engaged relative to the handle member  22  and the impaction tool  52  can be used to impact the acetabular prosthesis  40 . Further, the graspable portion  24  can be formed of an appropriate material to assist grasping by a user. For example, the graspable portion  24  can be formed of or covered with a soft or malleable material, such as a natural or synthetic rubber. In addition, the graspable portion can include ridges, knurls, or other detents or shapes to assist in grasping the graspable portion  24 . 
     The handle member  22  can define a through-bore or cannula  56 . The bore  56  can extend through the entirety of the handle member  22  such that the threaded rod  30  can extend into the handle member  22  through the cannula  56 , as discussed further herein. The threaded rod  30  can be inserted into the handle member  22 , generally, through the end including the impaction portion  50 . The threaded rod  30  can then be manipulated to engage the prosthesis  40 . 
     With particular reference to  FIGS. 2 and 3 , and continued reference to  FIG. 1 , the cannula  56  through the handle member  22  can be defined or formed through an outer wall  58  of the handle member  22 . The wall  58  with the handle member  22  can further include at least a shoulder or protrusion  60  that extends into the cannula. The shoulder can be formed at a transition in internal diameters of the cannula  56 . The cannula  56  can include a first internal diameter  62  near the prosthesis engaging end  26  and a second greater diameter  64  closer to the impaction portion  50 . The shoulder  60  can engage a complimentary or extending shoulder  66  of a bottom surface or slot wall  68  of a slot region or portion  70  of the threaded rod  30 , as discussed further herein. 
     Additionally, a protruding member or protrusion  74  can extend a distance  76  into the internal diameter  64  of the cannula  56 . The protrusion  74  can extend the distance  76  into the cannula  56  to engage the slotted region  70  of the threaded rod  30 . The protrusion  74  can be formed as a separate member that is inserted into a passage or bore  78  of the handle member  22 . It is understood, however, that the protruding member  74  can also be formed integrally with the handle member  22  as a single piece. Also, the distance  76  that the protrusion extends can be selected based on an amount of resist selected to maintain the threaded rod  30  in the handle member  22 . 
     The threaded rod  30  that includes the slot region  70  can generally include a double-“J” or double-bayonet slot configuration. In the double-J slot configuration, a first entry passage or opening  80  is formed through the slot wall  68  that leads into a first circumferential groove or path  82 . The slot wall  68  can also be referred to as a slot wall and the first groove  82  can be a short or non-complete circumferential groove defined at least in part by the slot wall  68 . The short groove  82  is a partial circumferential passage. 
     The short groove  82  passes at least a certain distance around the threaded rod  30  to a second passage or opening  84 . Generally, however, the short groove  82  does not circumscribe the threaded rod  30 . A second passage or opening  84  can open from the short groove  82  and into a long groove  86 . The long groove or complete path  86  is a complete circumferential passage or path that surrounds the entire circumference of the threaded rod  30 . The complete path  86  is defined as an area of clearance or uninterrupted area between a second slot region ledge  88  and a third or proximal ledge  90 . The second opening is through the second slot wall  88 . It is understood, however, that the short groove  82  can be a complete groove (i.e. a groove that completely circumscribes the threaded rod  30 ) as long as the first opening  80  is not aligned with the second opening  84 . 
     As discussed further herein, the projection member  74  can pass through the slot region  70  by passing through the first opening  80 , moving into and through the short groove  82 , and then through the second opening  84  into the complete circumferential area or passage  86 . As discussed further herein, the threaded rod  30  can be rotated completely, at least once and generally multiple times, when the projection  74  is positioned in and riding within the complete circumferential passage  86 . The double-“J” slot configuration is to provide a serpentine path for the projection  74  such that the threaded rod  30  can be efficiently maintained within the handle member  22 . Thus, as discussed above, the short groove  82  can be provided to circumscribe the threaded rod  30  so long as the two openings  80 ,  84  are not aligned along the length of the threaded rod  30 . When the openings  80 ,  84  are not aligned then the threaded rod  30  must be rotated for the threaded rod  30  to move relative to the projection  74 . 
     A tool engaging region or portion  96  can be defined by an end of the threaded rod  30  to manipulate and twist the threaded rod  30  relative to the handle member  22 . An insertion or driver tool  100  that engages the tool engagement region  96  can be formed to pass through at least a portion of the cannula  56  to engage the threaded rod  30  when it is positioned within the cannula  56 . The driving tool  100  can include a driving tip  102  that engages the tool engaging region  96  of the threaded rod  30 . The driving tip  102  can be any appropriate shape, such as a hex-drive, cruciform, or other driving shape. As illustrated the driving tip  102  can be a rounded or curved hex shaped drive. The driver tool  100  can include a handle  104  to be grasped by a user to rotate the driver instrument  100  to rotate the threaded rod  30 . 
     With continuing reference to  FIGS. 1-4B  and additional reference to  FIGS. 5 ,  6 , and  7 , the threaded rod  30  can be positioned into the handle member  22  by insertion into the cannula  56 , such as through an opening  105 . The projection member  74  can engage the first opening  80  and pass there through. The projection member  74  can engage or move through the opening  80  by rotating the threaded rod  30 , such as with the driving tool  100 , to align the opening  80  with the projection  74 . 
     While continuing to move the threaded rod  30  generally in the direction of Arrow A, the insertion or driving instrument  100  can be used to rotate the threaded rod  30  to move the threaded rod  30  relative to the projection member  74  such that the projection member  74  rides or moves within the semi-circumferential passage  82 . After a selected amount of rotation, such as a one-quarter (e.g. about 90 degrees of rotation) to about three-quarters (e.g. about 270 degrees of rotation), including about one-half rotation (e.g. about 180 degrees of rotation) of the threaded rod  30 , the projection member  74  can be aligned with the second opening  84 . The driving member  100  can apply axial force and rotation motion substantially simultaneously, thus, when the projection  74  is aligned with the opening  84  the projection  74  will move through the opening  84  and into the complete circumferential groove or passage  86 . The interactions of the projection  74  and the slot portion  70  are illustrated generally in  4 A- 7 . 
     Once the projection member  74  is within the complete circumferential passage  86 , the threaded rod can be rotated 360° around its axis while it is within the cannula  56  of the handle member  22 . When the threaded rod  30  is rotated relative to the handle member  22 , the threaded end or thread  36  of the rod  30  can be threaded into the threaded bore  42  of the acetabular prosthesis  40 . The threaded rod  30  is generally rotated within the cannula  56  of the handle member  22  with the driver  100 . The driver  100  can be manipulated from an exterior of the handle member  22  through an opening  105  in the handle member  22 , as illustrated in  FIG. 5 . 
     As the threaded rod  30  is threaded into the acetabular prosthesis  40 , the acetabular prosthesis can be moved in the direction of Arrow B towards the shaped end or prosthesis engaging end  26  of the handle member  22 . As the prosthesis engaging end  26  includes at least a flat side or a keyed portion  112 , the acetabular prosthesis  40  can include a complementary depression or passage  110  to engage or interact with a flat or keyed portion  112  of the prosthesis engaging end  26  of the handle member  22 . The rotation of the threaded rod  30  and the interaction of the threads  36  of the threaded rod  30  and the threaded bore  42  of the acetabular prosthesis  40  can interact to move the acetabular prosthesis  40  into a tight and fixed engagement relative to the keyed portion  112  of the handle member  22 . Accordingly, the acetabular prosthesis  40  can be rotationally fixed relative to the handle member  22  due to the interaction and complementary configuration of the acetabular prosthesis  40  keyed depression  110  and the handle member keyed portion  112 . Additionally, due to the threaded engagement of the threaded rod  30  with the acetabular prosthesis  40  and the positioning of the shoulder  60  within the cannula  56  of the handle member  22  and the complementary shoulder  66  of the threaded rod  30 , the acetabular prosthesis  40  is also substantially axially fixed relative to the handle member  22 . The projection  74  within the continuous or circumferential groove  86  assists in holding the threaded rod  30  within the handle member  22 . 
     Due to the connection of the acetabular prosthesis  40  with the handle member  22  and the threaded rod  30 , a user can control both position and version (i.e., rotational control) of the acetabular prosthesis  40  during an implantation procedure. As illustrated in  FIG. 8 , the acetabular prosthesis  40  can be positioned into a prepared acetabulum  120  of a pelvis  122 . The pelvis  122  can be in appropriate subject, such as a human subject. The mallet  52  can be used to impact the acetabular prosthesis  4  through the insertion assembly  20 , including the handle member  22 . Again, the handle member  22  is substantially in direct contact with the acetabular prosthesis  40  due to the connection of the threaded rod  30  and the handle member  22 , as discussed above. Accordingly, the impaction from the mallet  52  is directed substantially through the handle member  22  onto and into the acetabular prosthesis  40  to drive the acetabular prosthesis  40  into the prepared acetabulum  120 . 
     Once the acetabular prosthesis  40  is properly or selectively positioned within the acetabulum  120 , the insertion assembly  20  can be removed from the acetabular prosthesis  40 . Substantially in reverse of the connection process discussed above, the driving tool  100  can be passed through the cannula  56  to engage the threaded rod  30  at the tool engaging region  96  to unthread the threaded rod  30  from the acetabular prosthesis  40 . Once the threaded rod  30  is disengaged from the acetabular prosthesis  40 , the insertion assembly  20  can be removed from the acetabular prosthesis  40  as a single unit as the threaded rod  30  is captured within the insertion handle member  20  by the projection  74  in the substantially continuous groove or passage  86 . 
     Once removed from the acetabular prosthesis  40 , the insertion assembly  20  can then be disassembled for cleaning. The insertion assembly  20  can be disassembled into substantially two components by moving the threaded rod  30  such that the projection  74  passes first through the second opening  84 , is then rotated through the short groove  82 , and then through the first opening  80 . Once the projection is moved through the first opening  80  and generally out of the slot region  70 , the threaded rod  30  can be withdrawn from the insertion handle member  22  substantially through the opening  105  near the impaction plate  50 . Accordingly, the two members, including the handle member  22  and the substantially solid threaded rod  30 , can be cleaned in an appropriate manner, such as with a cleaning solution and/or an autoclave or similar heat sterilization or chemical sterilization system. 
     According to various embodiment, as illustrated in  FIGS. 9 and 10 , an insertion assembly  200  is illustrated. The insertion assembly  200  can include portions that are similar to that illustrated and discussed relative to the insertion assembly  20  above. Those portions that are substantially similar will be discussed only briefly here. For example, the insertion assembly  200  can include a handle member  202  that includes a graspable region or portion  204  similar to the graspable region  24  discussed above. An impaction plate  206  can also be provided at an end of the handle member  202 . 
     The handle member  202  can include an arcuate portion or member  210 . The arcuate member  210  can be an extended or prosthesis engaging portion or member that is defined by a curve or an arc having a radius  212 . The arcuate member  210  can assist in allowing for placement of the acetabular prosthesis  40  substantially around a minimally dislocated femur to allow for a less invasive procedure, including less disruption of soft tissue and a smaller incision. The arcuate member  210  can define a cannula  222  along a selected length of the arcuate member  210 . A depression or groove  220  can be defined through at least a portion of the arcuate member  210 . The groove  220  can extend to the cannula or through-bore  222  defined through an end  224  of a wall  226  of the arcuate member  210 . Near the end  224  can be a prosthesis engaging keyed surface  228  that can have a substantially keyed or non-circular configuration similar to the end  26  of the insertion assembly  20 , discussed above. 
     A projection  230  can extend a distance  232  into the cannula  222  similar to the projection  74 , discussed above. A threaded rod  240 , as illustrated in  FIG. 10 , can be positioned in the cannula  222  and manipulated substantially similarly to the threaded rod  30  discussed above. The threaded rod  240 , however, can include a length that is shorter than the threaded rod  30  discussed above to fit within the cannula  222  and allow the driving instrument  100  to engage a tool engaging end  242  through the groove  220 . 
     The threaded rod  240  can include a threaded end  246  that includes threads  248  similar to the thread of the threaded rod  30  discussed above. The threads  248  can be manipulated to engage the prosthesis  40 . As discussed above, rotating the threaded rod  240  to engage the acetabular prosthesis  40  can move the prosthesis  40  to engage the end  224  of the handle member  22 . 
     The threaded rod  240  can also include a slot region  250  similar, or even identical, to the slot region  70  of the threaded rod  30 , discussed above. The slot region  250  can include a first slot opening  252  through which the projection member  230  can pass into a semi-circumferential passage or short groove  254 . The threaded rod  240  can then be rotated until the projection member  230  is able to pass through a second opening  256 . 
     Once the projection member  230  is through the second opening  256 , the threaded rod  240  can be moved relative to the projection member  230  to allow the projection member  230  to pass into an uninterrupted area  258  that is an area of clearance that is opposite the threaded end  246 . The area of clearance  258  can be defined beyond a first wall  260  of the threaded rod  240  that is opposite the threaded end  246 . The area of clearance  258  can be considered a complete path or long groove that allows rotation of the threaded rod  240 . Accordingly, once the projection member  230  is beyond the end wall  260  and in the area of clearance  258 , the threaded rod  240  can be rotated 360° at least one time, and generally a plurality of times, to turn the threads  248  to engage the threaded bore  42  of the prosthesis  40 . 
     By rotating the threaded rod  240 , the threaded rod  240  can be engaged and disengaged from the prosthesis  40  similar to the process of the threaded rod  30 , discussed above. The insertion assembly  200  can, therefore, be operated substantially similar to the insertion assembly  20  discussed above save for the configuration of the arcuate portion  210  and the shortened length of the threaded rod  240  due to the positioning of the cannula  222  substantially only at an end of the arcuate member  210 . 
     Accordingly, the insertion assemblies  20 ,  200  can be used to insert the acetabular prosthesis  40 , or any appropriate member or prosthesis, while having substantially both axial positional control and version (i.e., rotational) control of the acetabular prosthesis  40 . While having at least the two degrees of freedom of control of the acetabular prosthesis  40 , the acetabular prosthesis  40  can be substantially precisely positioned within the prepared acetabulum  120  of the pelvis  122 . It is understood that a procedure can further include removing the insertion assemblies  20 ,  200 , as discussed above, and positioning a liner within the acetabular prosthesis  40 , reducing a femur into the acetabular prosthesis  40 , either with a natural femoral head or a femoral prosthesis member, or any other appropriate procedure step. Regardless, the insertion assemblies  20 ,  200  can include substantially two components that can be efficiently disassembled for ease of cleaning and efficiently assembled for engagement of an acetabular prosthesis in both rotational and axial position control. 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.