Metatarsal arthroplasty devices, systems, and methods
Implants, systems, instruments, methods, and kits for metatarsophalangeal joint arthroplasty may include metatarsal arthroplasty implants, repositioning guides, broach tools, inserter tools, and sterilizable packaging configured to facilitate metatarsal arthroplasty surgical procedures. The metatarsal arthroplasty implants may generally include an articular member having a convex articular surface, a concave bone-facing surface opposite the convex articular surface, and at least one side surface intermediate the convex articular surface and the concave bone-facing surface, as well as a central shaft sized for insertion into a metatarsal bone having a central shaft longitudinal axis, a central shaft proximal end coupled to the concave bone-facing surface of the articular member, and a central shaft distal end extending away from the concave bone-facing surface of the articular member along the central shaft longitudinal axis.
1 . A metatarsal arthroplasty implant comprising:
an articular member comprising:
a convex articular surface;
a concave bone-facing surface opposite the convex articular surface; and
at least one side surface intermediate the convex articular surface and the concave bone-facing surface;
a central shaft sized for insertion into a metatarsal bone comprising:
a central shaft longitudinal axis;
a central shaft proximal end coupled to the concave bone-facing surface of the articular member;
a central shaft distal end extending away from the concave bone-facing surface of the articular member along the central shaft longitudinal axis; and
a plurality of barbs formed in the central shaft and shaped to resist removal of the central shaft from the metatarsal bone; and
at least one anti-rotation pin spaced apart from the central shaft and sized for insertion into the metatarsal bone adjacent the central shaft, the at least one anti-rotation pin comprising:
an anti-rotation pin longitudinal axis, wherein the anti-rotation pin longitudinal axis is substantially parallel to the central shaft longitudinal axis;
an anti-rotation pin proximal end coupled to the concave bone-facing surface of the articular member;
an anti-rotation pin distal end extending away from the concave bone-facing surface of the articular member along the anti-rotation pin longitudinal axis;
at least one barb formed in the at least one anti-rotation pin that is shaped to resist removal of the at least one anti-rotation pin from the metatarsal bone; and
at least one rib member extending to connect the at least one anti-rotation pin to the central shaft, the at least one rib member coupling a proximal portion of the at least one anti-rotation pin to a proximal portion of the central shaft;
wherein:
the central shaft is longer than the at least one anti-rotation pin;
each of the barbs of the central shaft and the anti-rotation pin is shaped to resist removal from the metatarsal bone; and
each of the barbs of the central shaft and the anti-rotation pin comprises a tapered leading end configured to facilitate insertion into the metatarsal bone.
2 . The metatarsal arthroplasty implant of claim 1 , wherein:
the articular member further comprises a plurality of notches formed in the at least one side surface with undercut surfaces extending below the convex articular surface configured to facilitate installation and removal of the metatarsal arthroplasty implant from the metatarsal bone.
3 . The metatarsal arthroplasty implant of claim 1 ,
wherein the at least one rib member is further coupled with the concave bone-facing surface.
4 . The metatarsal arthroplasty implant of claim 1 , wherein a first cross-sectional diameter of the central shaft proximal end is greater than a second cross-sectional diameter of the central shaft distal end.
5 . The metatarsal arthroplasty implant of claim 1 , wherein the barbs of the central shaft extend circumferentially about the central shaft longitudinal axis such that the central shaft comprises a plurality of substantially circular cross-sectional shapes taken transverse the central shaft longitudinal axis.
6 . A metatarsal arthroplasty implant comprising:
an articular member comprising:
a convex articular surface;
a concave bone-facing surface opposite the convex articular surface; and
at least one side surface intermediate the convex articular surface and the concave bone-facing surface;
a central shaft sized for insertion into a metatarsal bone comprising:
a central shaft longitudinal axis;
a central shaft proximal end coupled to the concave bone-facing surface of the articular member;
a central shaft distal end extending away from the concave bone-facing surface of the articular member; and
a plurality of barbs formed in the central shaft and shaped to resist removal of the central shaft from the metatarsal bone, each of the barbs having a tapered leading end configured to facilitate insertion of the central shaft into the metatarsal bone; and
at least one anti-rotation pin spaced apart from the central shaft and sized for insertion into the metatarsal bone adjacent the central shaft, the at least one anti-rotation pin comprising:
an anti-rotation pin longitudinal axis, wherein the anti-rotation pin longitudinal axis is substantially parallel to the central shaft longitudinal axis;
an anti-rotation pin proximal end coupled to the concave bone-facing surface of the articular member;
an anti-rotation pin distal end extending away from the concave bone-facing surface of the articular member; and
at least one barb shaped to resist removal of the at least one anti-rotation pin from the metatarsal bone, the at least one barb having a tapered leading end configured to facilitate insertion of the anti-rotation pin into the metatarsal bone; and
at least one rib member that radially projects from and couples a proximal portion of the central shaft to a proximal portion of the at least one anti-rotation pin;
wherein:
the central shaft is longer than the at least one anti-rotation pin;
the rib member comprises a height parallel to the central shaft longitudinal axis;
the rib member further comprises a width perpendicular to the height; and
the height at the proximal portion of the central shaft is less than a length of the central shaft and greater than the width.
7 . The metatarsal arthroplasty implant of claim 6 , wherein a first height of the at least one rib member proximate the central shaft is greater than a second height of the at least one rib member proximate the at least one anti-rotation pin.
8 . The metatarsal arthroplasty implant of claim 7 , wherein the at least one rib member comprises a substantially straight leading edge that extends between the first height and the second height of the at least one rib member.
9 . The metatarsal arthroplasty implant of claim 6 , wherein:
the at least one anti-rotation pin comprises three anti-rotation pins that are radially spaced apart from each other about the central shaft; and
the at least one rib member comprises three rib members that each radially project from the central shaft to couple with one of the three anti-rotation pins.
10 . The metatarsal arthroplasty implant of claim 9 , wherein the three anti-rotation pins are equally spaced apart from each other about the central shaft at 120 degree angles.
11 . The metatarsal arthroplasty implant of claim 1 , wherein the at least one anti-rotation pin comprises three anti-rotation pins that are radially spaced apart from each other about the central shaft.