Joint surface replacement system
Inventors
Vitale, Glenn C. • Parisi, Michael • CONLAN, WAYNE
Assignees
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Publication Number
US-11051946-B2
Publication Date
2021-07-06
Expiration Date
Abstract
The present invention relates to an articular joint replacement system. The system has first and second components. Each component has a tapered head piece for covering the end of a bone and for acting as an articular surface, an integrally formed screw stem having a length sufficient to extend into the medullary canal, and inwardly angled bone grips affixed to the underside of the head piece to allow solid fixation to the bone by compression press fit. The head piece of the first component is provided with a shaped exterior surface which complements the shaped exterior surface of the head piece of the second component and which allows motion in three planes.
Core Innovation
The invention relates to an articular surface replacement system in which an articular surface replacement component is implanted into an end of a first bone. The component includes an exterior articular surface defined by a convex head piece sized and configured to cover the end of the first bone, with an interior convex surface and an exterior convex surface connected by an outer periphery, and the convex head piece mates with a corresponding concave head configuration to provide an articular surface replacement.
The component has a centrally located stem extending from the convex head piece and a plurality of threads extending around the stem, with an integrally formed screw means adapted for fixation into the medullary canal. Anti-rotation locking is provided by a plurality of scalloped anti-rotation bone grips residing only in and around the peripheral edge and in and around the peripheral region of the interior surface, leaving portions of a smooth contiguous interior surface area between adjacent grips.
The disclosure further includes a sharp peripheral edge for engaging the bone, with head edge geometry designed to reduce lateral shear and loosening and to avoid articular interference. The described arrangement is intended to preserve subchondral bone and soft tissues while replacing cartilage, and to provide firm fixation for the implant.
Claims Coverage
The document provides two independent claims, each directed to an articular surface replacement component implanted into an end of a bone and specifically configured for a metatarsal component implanted into a metatarsal bone. Both independent claims share the core architecture of a convex head piece with an anti-rotation scalloped grip arrangement and a centrally located stem with threads, while one independent claim additionally specifies a sharp peripheral edge.
Convex head piece with smooth contiguous interior surface and peripheral edge
An exterior articular surface defined by a convex head piece dimensioned to cover the end of the first bone, the convex head piece having an interior convex surface, an exterior convex surface, and an outer periphery connecting the interior and exterior convex surfaces, wherein the interior surface of the convex head piece is a smooth contiguous surface area.
Scalloped anti-rotation bone grips confined to peripheral edge and interior regions
A plurality of scalloped anti-rotation bone grips in the peripheral edge of the convex head piece for gripping the end of the first bone and allowing solid fixation thereto, wherein the scalloped anti-rotation bone grips reside only in and around the peripheral edge of the convex head piece and at the interior surface of the convex head piece, whereby portions of the smooth contiguous surface area of the interior surface resides between adjacent scalloped anti-rotation bone grips.
Centrally located stem with circumferential threads
A centrally located stem extending from the convex head piece and a plurality of threads extending around the stem.
Sharp peripheral edge for engaging the bone
A sharp peripheral edge of the outer periphery for engaging the bone.
Metatarsal component for metatarsal bone implantation
Wherein the articular surface replacement component comprises a metatarsal component and the first bone comprises a metatarsal bone.
Scalloped anti-rotation bone grips depth range
Scalloped anti-rotation bone grips integrally formed with and residing in and around the peripheral edge and at a periphery of the interior surface of the convex head piece to a depth ranging from 0.5 mm to 1 mm, whereby portions of the smooth contiguous surface area of the interior surface resides between adjacent scalloped anti-rotation bone grips.
Across the two independent claims, the main claim coverage centers on an implantable metatarsal articular surface replacement component with a convex head piece defining a smooth contiguous interior surface, anti-rotation scalloped bone grips positioned in and around the peripheral edge and interior periphery with smooth surface regions between grips, and a centrally located stem with threads. One claim further requires a sharp peripheral edge for engaging the bone, and both specify a metatarsal/metatarsal-bone context, with the depth range of the scalloped grips recited in the second independent claim.
Stated Advantages
Low-mass/low weight to reduce breakage.
Replacement of cartilage only.
Three-plane motion.
Firm fixation.
Elimination of detritic synovitis.
Preservation of subchondral bone and soft tissues.
Radiographic visibility.
Reduced need for silicone/glues/grommets/in-growth jackets.
Documented Applications
Joint surface replacement system using matched partially spherical/tapered head components with convex/concave mating for articular surface replacement.
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