Abstract
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.
Claims
1. A hinge joint implant for an articulating two-component hinge joint, and arranged when in situ within a joint cavity to comprise a substantially at least hemi-spherocylindrical configuration, and further comprising: i) a sac formed of deformable material and comprising an outer layer; and ii) a filler inside the sac; 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 joint component surface it is in contact with, during articulation.
2. An implant as claimed in claim 1, wherein the implant does not move relative to the joint component surface at least partially due to coefficient of friction during articulation.
3. An implant as claimed in claim 1 or 2, wherein the implant does not move relative to the joint component surface at least partially due to an adhesive and/or mechanical fixture and/or a localised biological fixation.
4. An implant as claimed in any one of claims 1-3, wherein the implant comprises a substantially squashed spherocylindrical configuration.
5. An implant as claimed in any one of claims 1-4 and comprising a filler-filled implant of substantially capsule-like arrangement to be deformed when located in the joint cavity for articulated movement of the joint components.
6. An implant as claimed in claim 5, and arranged to exhibit the form substantially of a hemi-spherocylinder when compressed between the joint components.
7. An implant as claimed in claim 5 or 6 and comprising a gel-filled capsule.
8. An implant as claimed in any one of claims 5-7 and comprising a discrete pair of filler-filled implants.
9. An implant as claimed in claim 8, 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.
10. An implant as claimed in claim 1, 2 or 3, and comprising a substantially hollow spherocylindrical configuration.
11. An implant according to any preceding claim, wherein the sac includes an adhesive or mechanical fixture.
12. An implant according to any preceding claim, 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.
13. An implant according to any preceding claim, configured to be delivered minimally invasively/arthroscopically.
14. An implant according to any preceding claim, for inserting into a hinge joint in a hand, ankle, elbow, thumb, finger, or toe.
15. An implant according to any preceding claim, for inserting into a hinge joint in a finger.
16. An implant according to any preceding claim, wherein the hinge joint is an interphalangeal joint.
17. An implant according to claim 16, wherein the interphalangeal joint is a distal interphalangeal joint (DIP) and/or proximal interphalangeal joint (PIP).
18. An implant according to any preceding claim, wherein the sac comprises a polymer.
19. An implant according to claim 18, wherein the elastomeric polymer is selected from: polyhydroxyalkanoates, polycarbonate urethanes, polyurethane, urethane, silicones, polycarbonate urethane based silicones, and those based on cellulose.
20. An implant according to any preceding claim, comprising an external surface roughness or a coating to provide friction and/or act as an adhesive.
21. An implant according to any preceding claim, wherein the outer surface of the sac is coated with a coating material to facilitate bone and/or cartilage repair, and/or the filler material facilitates bone and/or cartilage repair.
22. An implant according to claim 21, wherein the coating material is pharmaceutically active; optionally wherein the coating material comprises stem cells and/or slow release.
23. An implant according to any preceding claim 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.
24. An implant according to any preceding claim for use in therapy.
25. An implant according to any preceding claim for use in the treatment or prophylaxis of a disease or condition in which the hinge joint is indicated.
26. An implant according to any preceding claim, wherein the implant is patient-specific.
27. An implant according to any preceding claim, and having regions of different wall thickness.
28. An implant according to claim 27 and comprising a dual thickness wall.
29. An implant according to claim 27 or 28 and having a wall with a localized region of increased thickness at a load-bearing region.
30. An implant according to claim 27, 28 or 29, wherein an edge of the thicker region serves to help define a fluid reservoir region within the implant.
31. An implant according to any preceding claim and including an engagement formation extending outwardly from the insert surface for assisting with locating and/or securing the insert to a bone of the joint.
32. An implant according to claim 31 wherein the engagement formation is arranged to be provided on a convex portion of the insert.
33. An implant according to claim 32, wherein the engagement formation comprises a flange or skirt.
34. An implant according to claim 31, 32 or 33, wherein the engagement formation extends in the order of 1 mm from main body of the insert.
35. An implant according to claim 31, 32, 33 or 34 wherein the engagement formation includes lug formations.
36. An implant according to claim 35, wherein the lug formations extend in the range 2 mm to 10 mm from the main body of the insert.
37. An implant according to any one or more of claims 31 to 36, wherein the engagement formation is formed at the join between pieces of an insert formed from multiple pieces.
38. Use of an implant according to any preceding claim for inserting into a hinge joint.
39. Use of an implant according to claims 1-37 for treating arthritis, and/or torn or damaged cartilage.
40. A method of locating an implant 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.
41. A method as claimed in claim 40, wherein the implant during location, and after subsequent compression, maintains substantially an at least hemi-spherocylindrical configuration.
42. A method as claimed in claim 40 or 41, wherein the implant comprises a filler-filled capsule maintaining substantially a capsule configuration during location and after subsequent compression.
43. A method as claimed in claim 40, wherein the implant comprises a filler-filled capsule arranged to be deformed from a capsule configuration during said compression.
44. A method as claimed in any one or more of claims 40-43, wherein the implant is retained in location at least partially by the coefficient of friction between outer surface of the implant and the surface of the joint components.
45. A method as claimed in any one or more of claims 40-44, 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.
46. A method as claimed in claim 45, wherein the adhesive material is delivered while the implant is in situ.
47. A method as claimed in claim 45, 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.
48. 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 any one of claims 1-37.
49. A method for forming the implant according to any one of claims 1-37 from one or more pieces.
50. A method according to claim 49, wherein the implant is manufactured from two or more pieces that are subsequently welded together.
Description
[0077] Aspects and embodiments of the present invention will now be described further, by way of example, with reference to the accompanying drawings, in which:
[0078] FIG. 1: FIG. 1A shows a view of the back section of the hinge joint implant having a hemi-spherocylindrical or spherocylindrical configuration, and FIGS. 1B and 1C depict three-dimensional views of the hinge joint implant having a capsule spherocylindrical before being squashed into a hemi-spherocylinder configuration;
[0079] FIG. 2: illustrates a hinge joint implant within a joint cavity between two joint components;
[0080] FIG. 3: is a view of the hinge joint implant having a hemi-spherocylindrical shape prior to implantation with a hollow centre;
[0081] FIG. 4: is a further illustration of a longitudinal cross-section of a hinge joint implant having a hemi-spherocylindrical configuration;
[0082] FIG. 5: FIG. 5A illustrates a hinge joint without an implant in place and then, and FIG. 5B shows a comparative hinge joint to FIG. 5A additionally with an implant in place;
[0083] FIG. 6: FIGS. 6A to 6D illustrate multiple front and back section views of a hinge joint implant, and with a sac and filler are also shown in FIGS. 6F and 6H;
[0084] FIG. 7: illustrates positioning of an implant within the joint cavity;
[0085] FIG. 8: illustrates multiple views of a hinge joint implant at different time points during flexion and extension of a simulated hinge joint;
[0086] FIG. 9: illustrates multiple front, back, and side views of joint components with which the invention interrelates;
[0087] FIG. 10: illustrates front, back, and side views of an embodiment of a capsule-shaped spherocylindrical implant;
[0088] FIG. 11: illustrates front, back, and side views of an embodiment of a capsule-shaped spherocylindrical implant wherein the implant is compressed/squashed;
[0089] FIG. 12: illustrates an example of a filler-filled capsule-implant;
[0090] FIG. 13: illustrates a double-implant in unsquashed and squashed (natural/deformed) spherocylindrical configuration;
[0091] FIG. 14: illustrates comparative configurations of the implant of the invention, specifically (A) a hemi-spherocylindrical; (B) a hemi-prolate spheroid; and (C) a spherical cap shape;
[0092] FIG. 15: illustrates various angles of flexion between the joint components when the implant is without a skirt and within the joint space between two joint components;
[0093] FIG. 16: illustrates various angles of flexion between the joint components when the implant is with a skirt and within the joint space and between two joint components;
[0094] FIG. 17: further illustrates how the dual thickness implant of the invention fits and functions between two joint components; and
[0095] FIG. 18: illustrates the skirted implant and when it is between two articulating joint components.
[0096] As illustrated in FIGS. 1A, 1B and 1C, the implant 10 of the present invention can comprise a hemi-spherocylindrical or a spherocylindrical configuration. It will be understood that the implant is illustrated from a back section view in FIG. 1A and three-dimensional views in FIGS. 1B and 1C. It will also be understood that the Figure is not to scale and the thickness of implant is such that it can be inserted into a hinge joint. Further, it will be understood that the respective thicknesses of the sac layers and the filler may vary depending on the embodiment of the invention, for example when the filler is enclosed in a “sandwich” within the sac layers and the implant comprises a hollow concave space versus when the filler occupies the entire internal space of the implant and fills the capsule
[0097] An exploded view of the implant 20 that extends beyond the joint cavity and located between two joint components which are two bone components 25 and 30 are illustrated in FIG. 2. The implant 20 may be of a consistent thickness throughout the implant or may have regions of different thicknesses, such as for example a dual thickness, or thicker or thinner in the central region (20a) than at the rim (20b). Initially, the implant 10 could be manufactured prior to creating the hemi-spherocylindrical configuration of the hinge joint implant 20 shown in FIG. 2. The joint components comprise for example, bones with/without cartilage 25 and 30. Generalised structures of the bones are shown to have either a concave 25 or a convex-end 30 surface. The implant 20 is shown to comprise a rim 20b and a central region 20a, and the curved ends of the implant 20 are shown to be configured such that they extend over the sides of the bone-end that has a convex-shape 30.
[0098] FIG. 3 is a three-dimensional representation of an example of a substantially hemi-spherocylindrical implant 20 of the present invention which comprises a concave region 22. The final shape of the implant will depend on the deformation in the joint during articulation. The concave region 22 can be suitably configured to extend over a joint component, for example a convex bone.
[0099] As illustrated in FIG. 4, a transverse cross section of an implant 40 embodying the present invention is shown which reveals the outer sac layer 42, and the filler 46 enclosed between the sac layers. The implant 40 is also shown to have a hollow centre. The sac 40 is made of suitable material, and a filler 42 made of suitable material and which is shown to be completely enclosed within the sac.
[0100] FIG. 5A depicts a representation of a hinge joint without an implant in which the joint component bones with/without cartilage 45 and 55 and ligaments 50 can be seen and FIG. 5B shows the hinge joint comprising an implant 60 embodying the invention, a convex bone 55 joint component, and a corresponding concave bone 45 joint component, wherein the ligaments 50 have not been compromised and remain intact. Thus, the minimally invasive implant 60 is another embodiment of the invention resulting in preservation of the ligaments during insertion into a patient. Thus the implant can be situated such that the ligaments 50 are not compromised. The hinge joint implant 60 is configured such that it fits within the joint cavity and the implant may extend over the ends of the convex bone with/without cartilage 55. FIG. 5B also shows the geometry and the kinematics of the implant 60 are controlled anatomically.
[0101] FIG. 6 illustrates a front, back, and side representations of an implant 70 embodying the invention in a state of motion between a convex bone with/without cartilage 65 and a concave bone with/without cartilage 75 as joint components. The implant 70 is positioned within the joint cavity and extending around the end of a joint component surface which is convex-shaped, for example bone and/or cartilage 65. The implant is shown in motion during flexion and extension of the hinge joint. FIGS. 6E to 6H additionally show side views of the implant 70 between bones 65 and 75 at the hinge joint during flexion and extension. The implant 70 comprising the sac 72 envelops a filler 74.
[0102] FIG. 7 illustrates an alternative embodiment of the implant of the invention 80 wherein the implant has a pre squashed spherocylindrical configuration and an outer sac layer and a filler that occupies or fills the entire implant. For example, the implant 80 is a gel-filled capsule. The implant 80 is shown in an exploded view at a joint cavity between joint components that are a convex bone with/without cartilage 85 and a concave bone with/without cartilage 90. It will be understood that the illustration is not to scale but represents the relative positioning of the implant between the joint components. As illustrated, the implant can fit entirely within the cavity and not extend around the sides of a joint component surface, such as bone with/without cartilage 85.
[0103] FIG. 8 represents another alternative embodiment wherein the implant of the invention 80 is shown to be located between joint components, a convex bone with/without cartilage 85 and a concave bone with/without cartilage 95, and functions through a caterpillar-track type motion and the implant 80 is shown to entirely fit within the joint cavity between the bones at the joint.
[0104] As is illustrated in FIG. 9, an implant of the invention 105 can comprise two separate pieces which are both spherocylindrical in configuration and when positioned under each of the condyles of the joint component bone with/without cartilage, for example between bones with/without cartilage 95 and 100 take on a deformed configuration 105a. The bones with/without cartilage 95 and 100 are provided with a two-piece implant 105 comprised of two pieces that are separate and optionally joined to each other, which have a spherocylindrical configuration and comprise a sac enveloping a filler. The implant 105 functions by improving hinge joint articulation by offering a caterpillar-track type motion.
[0105] FIG. 10 illustrates an implant of the invention 115 comprising an outer sac layer 117 and a filler 119 that completely occupies the internal space of the implant such that it fills the entire capsule. FIGS. 10D to 10F represent side-views of the same. FIG. 11 depicts the implant 115 positioned in an articulating two component joint. FIG. 11C illustrates the implant 115 having a deformed configuration and FIGS. 11D to 11F represent side-views of the same. The filler 117 comprises for example a gel, between the articulating joint components 110 and 120 at the hinge joint.
[0106] In one embodiment in FIG. 12 the implant can comprises a filler-filled capsule implant 135 which is gel-filled and with a substantially spherocylindrical configuration with an at least approximately cylindrical main body portion. The illustration is in an unsquashed spherocylindrical configuration 135 in FIG. 12A and in a squashed or slightly squashed spherocylindrical configuration 137 in FIG. 12B between the joint surface components 130 and 140, in which each component is for example a bone and/or cartilage in a hinge joint cavity. Bone 130 is shown to comprise a convex-end surface.
[0107] In an alternative embodiment in FIG. 13A the implant can take the form of at least a pair of implant members of substantially spherocylindrical configuration 150, although truncated with respect to the embodiment of FIG. 12, and which in one embodiment can approximate to a near oval or spherical shape/configuration. Once in location for use during joint articulation the pair of implant members adopt compressed/deformed configuration 155 as illustrated in FIG. 13B and squashed/compressed/deformed between the joint surface components 145 and 160, in which each component is for example a bone and/or cartilage in a hinge joint cavity. The bone 145 as illustrated comprises condyles.
[0108] As shown in FIG. 14, the implant with a (A) hemi-spherocylinder, (B) hemi-prolate spheroid, or (C) spherical cap shape is squashed to produce a caterpillar motion to simulate movement in a hinge joint. This geometry would be very suitable for small joints that are of a hinge configuration such as the metacarpophalangeal (MCP) proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints.
[0109] In one embodiment, as shown in FIG. 15, the implant 215 f the invention can have a dual thickness which permits joint articulation between the two joint components 210 and 220 and as an example of an implant with regions of different thickness as discussed in detail above The implant is shown to facilitate various angles of flexion such as 0° and 70°. The implant is also shown to have a localised thicker region (217) in the load bearing area, and lubricant reservoirs 218 thereby formed at the extremities of the implant 215.
[0110] FIG. 16 represents an embodiment of the implant of the invention 215 comprising a flange or skirt formation 217 on the implant. FIGS. 16A to 16C show how the implant with a flange/skirt formation 217 functions between the two joint components 210 and 220 during articulation. The flange/skirt 217 can serve to locate and/or assist the retention of the implant in position relative to the adjacent bone. Any form of connection/fixture arrangement to the bone can also be provided by way of the flange/skirt 217. Specifically, FIG. 16A shows the skirt-bearing implant positioned between the joint components 210 and 220 when the angle of flexion is 0°, whereas FIG. 16B illustrates how the skirted implant 215 facilitates movement of the joint components 210 and 220 when the angle of flexion is 70°.
[0111] FIG. 17 further represents an embodiment of the implant of the invention 230 comprising a dual thickness fits between the joint components 210 and 220. FIG. 17A illustrates the dual thickness implant 230 with a thicker middle region and thinner extremities which is shaped to fit around the sides of the convex joint component 210, and how that would work during flexion wherein the angle is >0°. FIG. 17B illustrates the dual thickness implant 230 in situ between the joint components 210 and 220, wherein the angle of flexion is 0°.
[0112] In a specific embodiment, the implant of the invention comprises a flange/skirt 217 as illustrated in FIG. 18. Several views of the implant 215 comprising a skirt 217 are shown in FIG. 18. The skirted implant is also shown between two joint components 210 and 220. The height to—which the skirt/flange 217 employed in any embodiment of the invention extends from the body of the implant 215 can advantageously be in the order of 1 mm. As illustrated, the flange/skirt can also be provided at the point of connection of two pieces of a multi-piece implant. The joint can be formed by any suitable process including laser-welding. Also, although not illustrated, the flange/skirt can exhibit lug or ear portion extending a yet greater distance from the implant 215 body. Such distance can be in the range 2 mm to 10 mm, and particularly in the order of 5 mm. These lugs/ears can advantageously further assist with the locating and securing of the implant relative to the adjoining bone of the joint.
