Apparatus And Method For Positioning A Prosthesis

According to various embodiments, a multi-use tool may include a member having a first surface and a second surface. The first surface can engage at least one of a shell and/or bearing liner for insertion thereof. The second surface may engage at least one of a shell and/or bearing liner for removal thereof.

DETAILED DESCRIPTION

According to various embodiments, a multi-use tool20, as illustrated inFIGS. 1A and 1Bmay be used and provided for performing various interactions with an acetabular shell (as discussed herein) and a liner to be positioned within the acetabular shell (as discussed herein). The multi-use tool20may generally be provided to have an exterior geometry or a selected geometry that substantially matches at least one of an acetabular shell or an acetabular liner. As exemplarily illustrated, the multi-use tool20has an external wall22that is substantially annular. The external wall22is an exterior wall surface of an annular ring24that extends around the multi-use tool20. Positioned internal to the ring24is a central hub26and one or more spokes or arms28a,28b, and28cthat extend from the central hub26to an internal wall surface30of the ring24. The multi-use tool20, including the ring24, the central hub26, and the arms28a-28c, may define a first side, as illustrated inFIG. 1A, which can be an acetabular cup engaging side40. A second side50of the multi-use tool20, as illustrated inFIG. 1B, can be a liner engaging or positioning side50. As discussed herein, the multi-use tool20can engage various portions of an acetabular shell, a liner, and various handles or insertion handles, for positioning and/or removing at least one of the acetabular shell or the acetabular liner. The multi-use tool20can, therefore, be used for a plurality of purposes during a procedure to either place an acetabular shell and/or liner or remove at least one of the acetabular shell and/or liner.

The shell engaging side40can include a shell facing surface52which may or may not contact an acetabular shell, as discussed herein. An anti-rotation tab56a,56b, and56ccan be formed to extend from a raised portion of each of the respective arms28a-28c. Each of the anti-rotation tabs56a-56ccan engage at least one anti-rotation scallop or recess58of a acetabular shell60, as illustrated inFIG. 2. As discussed further herein, the anti-rotation tab56a-56ccan engage respective recesses58of the acetabular shell60to rotationally fix the shell60relative to the multi-use tool20. The anti-rotation tabs56a-56ccan be positioned within the respective recesses58at any selected orientation. That is, the multi-use tool20can be rotated relative to the shell60and the anti-rotation tabs56a-56ccan register in any selected three scallop recesses58of the shell60. Therefore, the multi-use tool20can be efficiently and quickly positioned relative to the shell60in any selected rotational position. Once the shell60is positioned relative to the multi-use tool such that the anti-rotation tabs56a-56care engaged or received within the scallop recesses58the shell60is unable to rotate relative to the multi-use tool20. It is understood, however, that the shell60and the multi-use tool20can include a keyed portion such as the multi-use tool20will engage the shell60in only a single orientation.

After positioning the multi-use tool20relative to the shell60, the anti-rotation tabs56a-56ccontact an internal surface of the scallop recess58. The scallop recesses can include those such as in the acetabular shell used with the RINGLOC® orthopedic prosthesis system sold by Biomet, Inc. having a place in Warsaw, Ind. Additionally, a surface of the arm facing the cup60can engage near the scallop recesses58to provide a surface area for impacting the shell60into a patient. According to various embodiments, the surface52of the ring24need not directly contact the shell60. It is understood, however, that the surface52of the ring24can engage the shell60if selected.

The central hub26can also include a threaded boss70that can have internal and/or external threads to engage a handle72. The handle72can have internal or external threads to engage the threaded boss70. Accordingly, the multi-use tool20can be axially fixed relative to the handle72for use of the multi-use tool relative to the shell60. Additionally, the handle72can be rotationally fixed relative to the multi-use tool20by a locking feature or locking thread, such as a counter-threaded nut to fix the handle72relative to the multi-use tool20.

The multi-use tool20, as illustrated inFIG. 1B, can also include a bearing facing an engaging side. The bearing engaging side50can include one or more shell interface tabs80a,80b, and80c. The tabs80a-80ccan engage recesses in the shell60, as discussed further herein. The tabs80a-80care illustrated as being substantially aligned with the arms28a-28c, but it is understood that this is not required.

The tabs80a-80ccan include dimensions that are appropriate for engaging recesses in the shell60. For example, a length and width of the tabs80a-80ccan be provided to engage the shell60in a manner to allow for a vibrational force to be transmitted to the shell, as discussed further herein. Moreover, the tabs80a-80ccan include a height to allow the tabs80a-80cto bottom out within the respective recesses310as discussed further herein.

Formed on the liner facing side50can be one or more non-metallic buffer members90a,90b, and90c. As discussed herein, a liner can be positioned against the buffers90a-90cto limit or eliminate contact with other portions of the multi-use tool20and, particularly, the material that forms the remainder of the multi-use tool20. The multi-use tool20can be formed of a material, such as a metal or metal alloy, and the buffers90a-90ccan be formed of a non-metallic material, such as a selected polymer, carbon material, fabric, etc. The non-metallic buffers90a-90ccan substantially eliminate scratching or transfer of metal particles between the liner and the multi-use tool20. Therefore, the buffers90a-90ccan eliminate or substantially minimize scratching of the liner by the multi-use tool20. This can also eliminate or substantially reduce wear debris that may be created due to contact between the multi-use tool20and a respective liner.

The multi-use tool20can further include a guide hole or guide-bore100. The guide-bore100is formed through the ring24of the multi-use tool20. As discussed further herein, the guide-bore100can be used to form a pilot hole or guide hole in a liner to assist in removal of the liner from the acetabular shell60. According to various embodiments, the guide-bore100can be formed at an angle, as discussed and illustrated further herein, relative to a central axis of the multi-use tool20.

With continuing reference toFIGS. 1A and 1B, and additional reference toFIG. 2, the multi-use tool can be used in one or more manners to insert the shell60. The shell60can be positioned within a pelvis112of a patient after selected preparation of an acetabulum110of the patient. As is generally understood in the art, the acetabulum110of the pelvis112can be prepared such as by reaming, resection, and the like. After appropriate preparation of the acetabulum110, the shell60can be positioned within the acetabulum110in a selected manner. As is generally known in the art, fixation of the acetabular shell60can be made with the acetabulum110. For example, the acetabular shell60can include at least one throughbore or passage hole116for allowing a screw to pass through the shell60to engage the acetabulum110. Additionally, the shell60can include an apical depression or throughbore118to assist in engaging an insertion tool.

According to various embodiments, the multi-use tool20may engage the anti-rotation scallops58of the shell60with the anti-rotation tabs56a-56c. The anti-rotation tabs56a-56cfix the shell60rotationally relative to the multi-use tool20. The handle or insertion rod72can threadably engage the multi-use tool20to axially and rotationally fix the multi-use tool20relative to the insertion rod72. The interconnection of the insertion rod72with the multi-use tool20allows for the multi-use tool20to hold the shell60in a selected orientation relative to the acetabulum110during an insertion. During an insertion or implantation, the insertion rod72can be impacted with an impaction hammer120on an impaction end122, as is generally known in the art. The multi-use tool20, however, can assist in holding the shell60in a selected orientation and/or location during of the tool20impaction with the impaction tool120.

With continuing reference toFIGS. 1A-2, and additional reference toFIG. 3, a quick connect member150can also be provided to engage the shell60. The engagement of the quick connect member150with the shell60can be at the apical hole118. The apical hole may include a ridge or groove160in a side wall162to receive projections or fingers164that extend from deflectable legs166. In one example, the ridge or groove can include an internal thread in the throughbore118. An appropriate number of the deflectable legs166can be formed to deflect relative to a body168during positioning of the quick insertion member150into the apical hole to engage the groove160. Spaced away from the deflectable legs160can be a multi-use tool connection section170. The multi-use tool connection section170that can include a groove172formed in a wall174of the quick connect member150. A deflectable or connection portion with the multi-use tool20at the hub70can engage the quick connect member150. Alternatively, or in addition to, the quick connect region of the multi-use tool hub70can be a threaded interconnection between the quick connect member150and the hub70.

Accordingly, via the quick connect member150, the multi-use tool20may engage the shell60. When the quick connect member150has engaged both the multi-use tool20and the shell60, the shell60is also axially fixed relative to the multi-use tool20. Therefore, with the quick connect member150in place, when the insertion rod72is fixed to the multi-use tool20, the insertion rod72is also axially fixed relative to the shell60. With the quick connect member150, the rod72can be both axially and rotationally fixed to the shell60by interconnection with the multi-use tool20. As discussed above, the multi-use tool20includes the anti-rotation tabs56a-56cto rotationally fix the shell relative to the multi-use tool20and to the rod72. The quick connect member150may then axially fix the shell60relative to the multi-use tool20, and in turn to the insertion rod72, when the quick connect member150is used. It is understood, however, that the quick connect member150is not required to engage the shell60for insertion of the shell60. The multi-use tool20alone can then directly engage the shell60to rotationally fix the shell60relative to the multi-use tool20, and then, in turn, to the rod72. The user can determine the amount of fixation and limitation of motion between the shell60and the rod72by selection of use of the multi-use tool20alone, or the multi-use tool20used with the quick connect member150.

The shell60can have inserted therein a liner that is configured to articulate with a portion of a proximal femur, such as a natural proximal femur or a prosthetic proximal femur. The liner can be formed of a substantially hard and rigid material, including a ceramic material and/or a metal material. For example, a liner formed of ceramic in the C2a-Taper™ prosthesis system sold by Biomet, Inc. can be inserted into the shell60. A metal liner can include the cobalt-chromium alloy liner, such as that in the M2ATM-metal on metal articulation system, sold by Biomet, Inc., can also be positioned within the shell60to articulate with a selected proximal femur portion.

With continuing reference toFIGS. 1 and 3, and additional reference toFIG. 4, a liner formed of a hard material, referenced herein as a hard-liner200is illustrated. The hard-liner200can include a male taper202to engage a female taper (not specifically illustrated here) in the shell60to fix or engage the hard-liner200with the shell60. Hard-liners are generally known in the art and may include a male taper formed on the liner to engage a female taper in the shell, such as the C2a-Taper™ prosthesis system sold by Biomet, Inc. Accordingly, a description of the hard-liner and the shell taper configuration is not specifically included herein. Nevertheless, the multi-use tool20can be used to engage the hard-liner200, as discussed further herein.

Initially, with continuing reference toFIG. 4, the multi-use tool20can be used to engage the hard-liner200. As discussed above, the multi-use tool20can include at least the non-metallic buffer pads90a-90cto contact an upper rim210of the hard-liner200. The non-metallic buffer pads90a-90ccan be formed of a material that is softer than the hard-liner200and generally less able or likely to scratch or form debris when engaging the hard-liner200, relative to the other portions of the multi-use tool20. For example, various polymers can be used as a buffer or cushioning material for the buffers90a-90c. The buffers90a-90ccan be positioned to engage the rim210of the hard-liner200generally internally relative to the ring24of the multi-use tool20. As discussed inFIGS. 1A-1Band further illustrated inFIG. 4, the side50of the multi-use tool20that includes the buffers90a-90cis opposite of the side40that engages the shell60. Accordingly, the multi-use tool can be used to engage both the hard-liner200and the shell60for positioning of the shell60within the anatomy and/or the hard-liner200within the shell60.

The multi-use tool20, as discussed above, can include the threaded hub70that can engage a thread of a sleeve220. The thread of the sleeve220can be an internal or an external thread to mate with an internal or external thread, respectively, of the hub70. Accordingly, an external thread on the hub70and internal thread on the sleeve220is not required, but exemplarily illustrated herein. The sleeve220engages the multi-use tool20at a first end222. The sleeve220may define an internal bore or cannula that has a shoulder224, as illustrated inFIG. 5. The shoulder224may hold a spring226spaced a distance away from the first end222of the sleeve220. It is understood, however, that the shoulder224can be positioned at any point along the sleeve220. Having the shoulder224spaced a distance from the first end222can be selected for various purposes, such as manufacturing, positioning a second end230a selected distance from the first end222for use by a user, or other appropriate reasons.

The spring226can be pressed against the shoulder224by an internal rod240. The internal rod240can include a second shoulder242that engages the spring226to compress it against the first shoulder224. A user can press a plunger end246to compress the spring226against the first shoulder224. By compressing the spring226against the first shoulder224, the rod240may move generally in the direction of Arrow C to move a first rod end250relative to the first sleeve end222. The spring226may bias the internal rod240generally in a direction of Arrow D, which can generally be opposite to Arrow C. In turn, the internal rod240is biased towards the second end230of the sleeve220.

As discussed above the sleeve220can engage the boss70of the multi-use tool20. The rod240can pass through the sleeve220and also through the central bore of the multi-use tool20. The rod240, therefore, can engage a suction cup or attachment member260. The suction cup member260can include a suction cup portion262that is formed as a suction cup member. The suction cup member260may be formed by silicone or rubberized polymer material that may deflect and engage the hard-liner200. As is generally known in the art, the hard-liner200can include an internal surface that can be an internal articulating surface270that is substantially smooth. The suction cup or attachment member262may engage the internal surface270of the hard-liner200to hold the hard-liner200relative to the multi-use tool20, such as with engagement to the buffer members90a-90c. The multi-use tool20after having engaged the hard-liner200with the suction cup member260is illustrated inFIG. 5. Illustrated inFIG. 6is after the suction cup member260is disengaged from the hard-liner200, which may be after the hard-liner200has been positioned in the shell60.

The engaging member260can include a rod connection portion280which may include an internal thread282to engage an external thread284of the rod240. It is understood that other connections between the rod240and the liner engaging member260may also be provided. For example, a snap fit, a friction/interference connection, or other connections can also be provided. Nevertheless, the assembly can be formed such that the sleeve220can engage the multi-use tool20with a first connection and the rod240can pass through the sleeve220and the multi-use tool20. Once the rod240is placed through the sleeve220and tool20it may engage the liner engaging member260. Moving the internal rod240relative to the sleeve220may allow the suction member260to press against and engage the liner200. Once engaged with the engagement member260, the rod240can be released and the spring may then bias the rod240and move the hard-liner200against the multi-use tool20, as illustrated inFIG. 5. Once the liner200is engaged against the multi-use tool20, the liner200can be positioned within the acetabular shell60. It is understood that the acetabular shell60can be positioned within the acetabulum110of the pelvis prior to positioning the liner200within the shell60.

As illustrated inFIGS. 5 and 6, the multi-use tool20can engage the shell60such that there is a gap300between the ring24and the upper rim of the shell60. The gap300is due to the length of the tabs80a-80bthat have engaged respective pockets310of the shell60. It is understood that a respective number or complementary number of pockets are formed in the shell60based upon the number of tabs80of the multi-use tool20, and only one is illustrated here for the purposes of the current disclosure. Nevertheless, any appropriate number such as 2, 3, 4 or more may be provided. Nevertheless, the tabs80a-80ccan engage their respective pockets310a-310cto hold the ring24of the multi-use tool20a selected distance away from the shell60. The tabs80a-80c, however, may bottom out and engage the pockets310a-310cof the shell60to substantially ensure that the ring24of the multi-use tool20is substantially square or aligned with the shell60.

The squaring of the multi-use tool20with the shell60can include ensuring that the male taper202of the liner200is square or aligned with a female taper320of the shell60. The female taper320can define a central or perpendicular axis320athat may be aligned with a central or perpendicular axis202aof the male taper202at insertion of the hard-liner200into the shell60. By ensuring that the axes320aand202aare substantially aligned, the liner200may seat properly and fully within the shell60. By ensuring a proper seat of the liner200within the shell60, a substantially reduced possibility of fracture or breaking of the liner200can occur. Accordingly, the liner200can be engaged against the multi-use tool20, via the buffer members90a-90c, to ensure that the liner200is square with the multi-use tool20. The multi-use tool20can then engage the shell60via the tabs80a-80cand the pockets310a-310cto ensure that the multi-use tool20is square and aligned with the shell60. In this way, as the liner200is square and aligned with a multi-use tool20, and the multi-use tool20is square and aligned with the shell60, the liner200is squared and aligned with the shell60.

As illustrated inFIG. 5, once the shell is aligned with the liner200, the central rod240can be compressed, generally in the direction of Arrow C, to move the liner200into the shell60. Once the liner200is engaged in the shell60, the rod240can be released from the force that moves it in the direction of Arrow C. Removing the force will allow the spring226to bias the rod240generally in the direction of Arrow D, as illustrated inFIG. 6. As the liner200is seated within the shell60, a force of the suction cup portion262of the engagement member260can be overcome by the biasing force of the spring226and the suction cup member262can disengage the liner200, as illustrated inFIG. 6. The tabs80a-80cwill then be easily disengaged from the pockets310a-310cof the shell60. This can allow the liner200to be properly seated in a substantially squared and aligned manner and orientation with the shell60during positioning of the liner200within the shell60.

In addition to insertion of the hard-liner200, with the tabs80a-80c, the multi-use tool20can assist in removal of the hard-liner200as well. Once the hard-liner200is seated and engaged in the shell60, the taper of the hard-liner200is engaged with the taper of the shell60. A selected vibration induced in the shell60, however, can disengage the hard-liner200from the taper connection with the shell60.

Once the hard-liner200is disengaged from the taper connection, the hard-liner200can be removed from the shell60. Removal of the hard-liner200from the shell60can be according to various mechanisms such as manual manipulation with a digit of a user or a grasping tool. Additionally, a suction cup member, similar to that used for insertion of the hard-liner200, can be used to engage the hard-liner200to remove it from the shell60. Accordingly, the multi-use tool20can be used for both insertion and removal of the hard-liner200from the shell60.

The multi-use tool20, as illustrated inFIG. 7can be used in conjunction with a pilot bore drill400to form a pilot hole in a soft-liner420that has been positioned in the shell60. The soft liner420can be formed of a selected material, such as a polymer, including a high molecular weight polyethylene, or other selected material generally used for forming acetabular bearing liners of the shell60for an acetabular prosthesis. The soft-liner can be formed to have a central axis420a. The pilot hole drill400can include a drill shaft430and a drill tip432. The drill tip432can be of a selected length to pass through the guide-bore100of the multi-use tool20to engage the soft liner420to form a pilot bore454(illustrated inFIGS. 8 and 9) therein. For example, the drill tip432can include a length to extend through the multi-use tool20and engage the soft liner420for a selected distance, such as about 3 mm to about 10 mm. In addition, the guide-bore100can include a longitudinal axis440that is formed at an angle to a central axis20aof the multi-use-tool20and/or the soft-liner axis420a. Therefore, when the multi-use tool20is positioned on the shell60, as illustrated inFIG. 8, the axis440of the guide-bore100is angled relative to the central axis of the multi-use tool20. Again, the multi-use tool20may engage the shell60via the tabs80a-80cthat engage the pockets310a-310cof the shell60at the rim. The multi-use tool20can be positioned relative to the shell60with the insertion rod72or any other selected member that can engage the multi-use tool20.

The guide-bore100can allow the drill bit tip432to engage the soft liner420along the axis440of the guide-bore100such that a straight line along the axis440engages the interior surface of the shell60at a point450closer to the apical hole118than a locking or engagement groove452within the shell60. Accordingly, the axis440intersects the interior surface of the shell60in a position that does not interfere with any locking portions of the shell60. Generally, a taper locking portion to engage a hard-liner is also positioned further toward the rim of the shell60than the apical hole118. Thus, the pilot bore454can be formed in the soft liner420using the drill tip432through the guide-bore100.

Once the pilot bore454is formed within the soft liner420, the drill400can be removed, with reference toFIG. 9, and the multi-use tool20can also be removed from the shell60. Turning reference toFIGS. 10 and 11, the pilot bore454formed within the soft liner420can guide a soft liner removal tool460into the pilot bore454generally along the axis440anow defined by the pilot bore454. The axis440a, being substantially identical to the axis440of the pilot bore454, ensures that the liner removal tool460engages the shell60at the position450spaced away from the locking groove452of the shell60.

The removal tool60can include a thread or spiral groove462that can engage the liner420during insertion of the liner removal tool460. The removal tool460can also include a sharpened tip464that can further engage and pass through the soft liner420. As the removal tool460moves along the axis440a, it will engage the shell60at or near the point450. Due to the threads462on the removal tool460, the liner420will begin to move generally in the direction of Arrow E towards the rim and away from the apical hole118of the shell60. This allows the liner420to be removed from the shell60due to movement along the removal tool460. The movement of the liner420will disengage any liner engagement or locking mechanism with the shell60and the liner420can then be removed from the shell60, as illustrated inFIG. 11.

The removal tool460engages the shell60away from regions where a liner would engage and be locked into the shell60. Because the removal tool460engages the shell60away from locking portions for the liner420or the hard-liner200, a new liner or revision liner can be positioned within the shell60without requiring replacement of the shell60. The guide-bore100allows for the formation of the pilot hole454in a selected orientation relative to the shell60to ensure that the removal tool460does not engage the shell60at a position that would damage or affect locking portions of the liner and shell60engagement.