Implant
The present invention is directed to a hinge joint implant ( 40 ) configured to fit in a joint cavity and which can comprise, when in situ, an at least hemi-spherocylindrical configuration, and further a hinge joint implant configured to fit in a joint cavity wherein the implant can extend around the sides of a joint component which may be a bone and/or cartilage. The invention further provides the use of a hinge joint implant according for treating arthritis, and/or torn cartilage, and a method for manufacturing a hinge joint implant from one or more pieces.
1 . A hinge joint implant for an articulating two-component hinge joint, the implant comprising:
i) a sac formed of deformable material and comprising an outer layer; and
ii) a filler inside the sac;
wherein, the implant comprises a spherocylindrical configuration when in a non-compressed condition, and comprises a deformed spherocylindrical configuration comprising a substantially hemi-spherocylindrical configuration when in a compressed condition by being located in situ within a joint cavity defined by the articulating two-component hinge joint, and wherein the filler comprises a material with a coefficient of friction that allows opposite sides of the sac to move relative to one another when a force is applied to the joint, and an outer surface of the sac is arranged not to move relative to the naturally occurring joint component surface it is in contact with, during articulation, and wherein the amount of filler material is just sufficient to allow the relative movement within the sac.
2 . An implant as claimed in claim 1 , wherein the outer surface of the sac arranged not to move relative to the joint component surface does not move relative to the joint component surface at least partially due to the group consisting of: coefficient of friction during articulation, an adhesive, a mechanical fixture, a localised biological fixation, and combinations thereof.
3 . An implant as claimed in claim 1 , wherein the deformed spherocylindrical configuration comprises a substantially squashed spherocylindrical configuration or comprises a substantially hollow spherocylindrical configuration.
4 . An implant as claimed in claim 1 comprising a discrete pair of filler-filled implants, and arranged such that each of the pair of filler-filled implants is arranged to be deformed by a respective condyles of the joint components.
5 . An implant according to claim 1 , wherein the sac includes an adhesive or mechanical fixture.
6 . An implant according to claim 1 , wherein the implant comprises a thickness from about 0.01 mm to about 1.5 mm or from about 0.05 mm to about 0.8 mm.
7 . An implant according to claim 1 , for inserting into a hinge joint in a hand, ankle, elbow, thumb, finger, or toe, optionally wherein when the hinge joint is in a finger, the hinge joint is an interphalangeal joint comprising at least one of a distal interphalangeal joint (DIP) and a proximal interphalangeal joint (PIP).
8 . An implant according to claim 1 , wherein the sac comprises a polymer, optionally wherein the elastomeric polymer is selected from: polyhydroxyalkanoates, polycarbonate urethanes, polyurethane, urethane, silicones, polycarbonate urethane based silicones, and those based on cellulose.
9 . An implant according to claim 1 , comprising an external surface roughness or a coating to at least one of provide friction and act as an adhesive.
10 . An implant according to claim 1 , wherein the outer surface of the sac is coated with a coating material, and at least one of the coating material and the filler material facilitates at least one of bone and cartilage repair, optionally wherein the coating material is pharmaceutically active.
11 . An implant according to claim 1 wherein the filler material comprises a phospholipid, an elastomer, a gel, a hyaluronic acid based hydrogel, a natural polymer, and/or an alginate-based hydrogel.
12 . An implant according to claim 1 , having regions of different wall thickness comprising a dual thickness wall, with a localized region of increased thickness at a load-bearing region, wherein an edge of the load-bearing region serves to help define a fluid reservoir region within the implant.
13 . An implant according to claim 1 and including an engagement formation for assisting with at least one of locating and securing the insert to a bone of the joint, wherein the engagement formation is arranged to be provided on a convex portion of the insert, and comprises a flange or skirt extending from a main body of the insert, and optionally wherein the engagement formation includes lug formations, optionally wherein the lug formations extend in the range 2 mm to 10 mm from the main body of the insert.
14 . A method of locating the implant of claim 1 within a hinge joint cavity including manipulating joint components and associated ligaments of the hinge joint and subsequently allowing the joint components to compress the implant for articulated movement of the joint.
15 . A method as claimed in claim 14 , wherein the implant during location, and after subsequent compression, maintains a substantially hemi-spherocylindrical configuration.
16 . A method as claimed in claim 14 , wherein the implant is retained in location at least partially by an adhesive material between the outer surface of the implant and the surface of the joint components, and wherein the adhesive material is delivered while the implant is in situ, optionally wherein the adhesive material is delivered by way of a bore provided through the joint component and opening beneath the surface of the in situ implant.
17 . A method of treating or prophylaxis of a disease or condition in which the hinge joint is indicated in a patient in need thereof, comprising administering the implant according to claim 1 , optionally wherein the disease or condition is at least one of arthritis, and torn or damaged cartilage.
18 . A method for forming the implant according to claim 1 from two or more pieces that are subsequently welded together.