Implant removal tool
An implant removal tool designed for efficient and precise removal of an acetabular cup or similar implants is disclosed. The tool includes an outer shaft and an internal shaft configured to move relative to the outer shaft. The internal shaft is operably connected to a cutting assembly comprising multiple inwardly curving, wedge-shaped blades. The blades transition from a retracted position to a closed position, forming a semicircular cutting path slightly larger than the outer diameter of the implant. This configuration allows for controlled rotation of the blades around the implant's outer surface, effectively severing surrounding bone while minimizing damage to adjacent bone and soft tissues. The tool may include interchangeable components to accommodate implants of varying sizes, ensuring adaptability across surgical scenarios. Additional features, such as a helical thread mechanism or drill compatibility, enhance usability and precision during revision surgeries.
1 . An implant removal tool, comprising:
an outer shaft defining an internal lumen and including a plurality of slots extending through a wall of the outer shaft proximate a distal end of the outer shaft, each slot of the plurality of slots having a length extending parallel to a central longitudinal axis of the outer shaft;
an internal shaft residing at least partially within the outer shaft and configured to move relative to the outer shaft, wherein a distal end of the internal shaft includes a stem bordered by opposing structural shoulders;
a cutting assembly in operable communication with the internal shaft, the cutting assembly including a plurality of blades with each blade having an inwardly curving, wedge shape that tapers along a length so as to progressively reduce a circumferential extent and terminate in a sharp point for cutting bone, wherein the cutting assembly further includes a translation-support structure having one or more inwardly extending retention members that extend through the plurality of slots and abut the stem between the opposing structural shoulders such that translation of the internal shaft caused translation of the translation-support structure and rotation of the plurality of blades;
wherein the plurality of blades are moveable between a retracted position and a closed position, wherein the plurality of blades establish a distal-most end of the tool when in the closed position;
wherein manipulation of the internal shaft causes the plurality of blades to transition between the retracted position and the closed position.
2 . The tool of claim 1 , further including a handle extending laterally from an outer surface of the outer shaft.
3 . The tool of claim 1 , wherein the internal shaft further includes a shank extending proximally from a proximal end of the outer shaft and the shank is configured to operably engage a drill or hammer drill or receive an impact from a percussion device.
4 . The tool of claim 1 , further including:
a helical thread on an internal surface of the outer shaft;
a corresponding helical thread on an external surface of the internal shaft;
whereby rotation of the internal shaft relative to the outer shaft causes the internal shaft to move in a longitudinal direction relative to the outer shaft.
5 . The tool of claim 1 , wherein the cutting assembly further includes:
one or more support arms extending between the translation-support structure and the plurality of blades such that translation of the translation-support structure causes rotation of the plurality of blades;
wherein each of the one or more support arms extending between the translation-support structure and the plurality of blades includes one or more rotational axes and each rotational axis is non-intersecting with a central longitudinal axis of the internal shaft.
6 . The tool of claim 5 , wherein each of the one or more support arms comprises a first arm segment pivotably attached to the translation-support structure and a second arm segment pivotably attached to the outer shaft, the first arm segment being pivotably attached to the second arm segment at a pivot joint.
7 . The tool of claim 6 , wherein the first arm segment and the second arm segment are laterally and radially offset from the central longitudinal axis of the internal shaft.
8 . The tool of claim 1 , wherein an outermost lateral expanse of the cutting assembly is established by diametrically opposed outer surfaces of a pair of blades from the plurality of blades.
9 . The tool of claim 1 , wherein each blade in the plurality of blades has a curvature that generally matches a curvature of a predetermined implant.
10 . The tool of claim 1 , wherein a single cutting path of each blade of the plurality of blades is configured to extend around a curvature of a semispherical implant in an amount that is equal to or less than approximately 50% and equal to or greater than approximately 25% of an outer surface of the semispherical implant.
11 . An implant removal tool, comprising:
an outer shaft defining an internal lumen and including an alignment structure secured to a distal end of the outer shaft, the outer shaft further including a plurality of slots extending through a wall of the outer shaft proximate the distal end and providing access to the internal lumen;
an internal shaft residing at least partially within the outer shaft and configured to move relative to the outer shaft, wherein a distal end of the internal shaft includes a stem bordered by opposing structural shoulders;
a cutting assembly in operable communication with the internal shaft, the cutting assembly including a plurality of blades, wherein the plurality of blades are moveable between a retracted position and a closed position in which the plurality of blades establish a distal-most end of the tool;
wherein the alignment structure is configured to be received within an internal cavity of a semispherical implant to align the implant removal tool relative to the semispherical implant while the plurality of blades are in the retracted position;
wherein the plurality of blades comprises three or more blades;
wherein the cutting assembly further includes a translation support structure having one or more inwardly extending retention members that extend through the plurality of slots and abut the stem between the opposing structural shoulders such that translation of the internal shaft causes translation of the translation-support structure and rotation of the plurality of blades;
wherein movement of the internal shaft relative to the outer shaft causes the plurality of blades to transition between the retracted position and the closed position.
12 . The tool of claim 11 , further including a handle extending laterally from an outer surface of the outer shaft.
13 . The tool of claim 11 , wherein the internal shaft further includes a shank extending proximally from a proximal end of the outer shaft, and the shank is configured to operably engage a drill or hammer drill or receive an impact from a percussion device.
14 . The tool of claim 11 , further including:
a helical thread on an internal surface of the outer shaft;
a corresponding helical thread on an external surface of the internal shaft;
whereby rotation of the internal shaft relative to the outer shaft causes the internal shaft to move relative to the outer shaft.
15 . The tool of claim 11 , wherein the cutting assembly further includes:
one or more support arms extending between the translation-support structure and the plurality of blades such that translation of the translation-support structure causes rotation of the plurality of blades;
wherein each of the one or more support arms extending between the translation-support structure and the plurality of blades includes one or more rotational axes and each rotational axis is non-intersecting with a central longitudinal axis of the internal shaft.
16 . The tool of claim 15 , wherein each of the one or more support arms comprises a first arm segment pivotably attached to the translation-support structure and a second arm segment pivotably attached to the outer shaft, the first arm segment being pivotably attached to the second arm segment at a pivot joint, and wherein the first arm segment and the second arm segment are laterally and radially offset from the central longitudinal axis of the internal shaft.
17 . The tool of claim 11 , wherein each blade in the plurality of blades has a curvature that generally matches a curvature of the semispherical in implant.
18 . The tool of claim 11 , wherein each of the plurality of blades has a shape such that a single cutting path of each blade a single cutting path of each blade of the plurality of blades is configured to extend around a curvature of the semispherical implant in an amount that is equal to or less than approximately 50% and equal to or greater than approximately 25% of an outer surface of the semispherical implant.
19 . The tool of claim 11 , wherein each of the plurality of blades tapers along a length so as to progressively reduce a circumferential extent and terminate in a sharp point for cutting bone.
20 . An implant removal tool, comprising:
a cutting assembly having a plurality of blades with each blade having an inwardly curving, wedge shape that tapers to a sharp point for cutting bone;
wherein the plurality of blades are moveable between a retracted position and a closed position, whereby each blade of the plurality of blades creates a single cutting path from transition of the plurality of blades from the retracted position to the closed position;
wherein each blade of the plurality of blades includes a sharpened side leading to the sharp point and the sharpened side is configured to slide overtop or below an adjacent blade of the plurality of blades when the plurality of blades are moved into the retracted position, and wherein each blade of the plurality of blades includes an L-shaped cutout;
wherein the tool is operably configured such that the single cutting path of each blade of the plurality of blades is configured to extend around a curvature of a semispherical implant in an amount that is equal to or less than approximately 50% and equal to or greater than approximately 25% of an outer surface of the semispherical implant to facilitate cutting bone and tissue surrounding the semispherical implant.
21 . The tool of claim 20 , further including:
an outer shaft;
an internal shaft residing at least partially within the outer shaft and configured to move in a longitudinal direction relative to the outer shaft;
wherein the internal shaft further includes a shank extending proximally from a proximal end of the outer shaft.
22 . The tool of claim 21 , further including:
a helical thread on an internal surface of the outer shaft;
a corresponding helical thread on an external surface of the internal shaft;
whereby rotation of the internal shaft relative to the outer shaft causes the internal shaft to move in the longitudinal direction relative to the outer shaft.
23 . The tool of claim 20 , wherein the cutting assembly further includes:
a translation-support structure in operable engagement with an internal shaft such that translation of the internal shaft causes translation of the translation-support structure; and
one or more support arms extending between the translation-support structure and the plurality of blades such that translation of the translation-support structure causes rotation of the plurality of blades;
wherein each of the one or more support arms extending between the translation-support structure and the plurality of blades includes one or more rotational axes and each rotational axis is non-intersecting with a central longitudinal axis of the internal shaft.