Abstract
An inverse shoulder prosthesis includes a glenoid implant and a humerus implant. The glenoid implant has a glenoid body with a convex dome shaped articulating surface. The articulating surface extends along a center axis, has specific radii in sagittal and frontal planes, and is oriented towards the humerus. The humerus implant has a humeral body and a concave inlay. The concave inlay has a center axis oriented towards the glenoid of a shoulder and has a specific inner radius. The second radius of the glenoid implant is proportionately smaller than the inner radius of the inlay, ensuring a precise fit and function. This configuration allows for improved joint mechanics and stability.
Claims
1. An inverse shoulder prosthesis comprising: a glenoid implant comprising a glenoid body having an articulating surface, wherein the articulating surface: has a convex dome shape, defines a first right hand coordinate system having a first x-axis, a first y-axis, a first z-axis, and a first point of origin, the first z-axis extending along a center axis of the glenoid body, (1) extending into a positive direction of the first z-axis, in positive and negative directions of the first x-axis, and in positive and negative directions of the first y-axis, or (2) being oriented towards a humerus and having a base in an anterior-posterior and a lateral-medial direction, and (1) having a first radius in a plane defined by the first y-axis and the first z-axis, and a second radius in a plane defined by the first x-axis and the first z-axis, or (2) having a first radius in a sagittal plane, and a second radius in a frontal plane; and a humerus implant comprising a humeral body and an inlay, wherein the inlay: has a concave shape, has a second coordinate system having a second x-axis, a second y-axis, a second z-axis, and a second point of origin, the second z-axis extending along a center axis of the inlay, (1) extending into a negative direction of the second z-axis, or (2) having a center axis oriented towards a glenoid of a shoulder, and a base in an anterior-posterior direction and a craniocaudally direction, and having an inner radius, wherein the second radius is from 0.8 to 0.95 times of the first radius, and the first radius is smaller than the inner radius of the inlay.
2. The inverse shoulder prosthesis of claim 1, wherein the second radius is from 0.9 to 0.92 times of the first radius.
3. The inverse shoulder prosthesis of claim 1, wherein the first radius and a length of the glenoid body along the first z-axis are the same.
4. The inverse shoulder prosthesis of claim 1, wherein the glenoid implant is displaceable along the first x-axis within the inlay.
5. The inverse shoulder prosthesis of claim 1, wherein the second radius is from 0.5 mm to 7.5 mm smaller than the inner radius of the inlay.
6. The inverse shoulder prosthesis of claim 5, wherein the second radius is from 2.5 mm to 7.5 mm smaller than the inner radius of the inlay.
7. The inverse shoulder prosthesis of claim 1, wherein the first radius extends from the first point of origin to the articulating surface, and wherein the first radius is constant in the plane defined by the first z-axis and the first y-axis.
8. The inverse shoulder prosthesis of claim 1, wherein the second radius extends from the first point of origin to the articulating surface, and wherein the second radius increases along the articulating surface starting from the first x-axis towards the first z-axis.
9. The inverse shoulder prosthesis of claim 1, wherein a first angle is formed between the z-axis and the first radius.
10. The inverse shoulder prosthesis of claim 1, wherein a second angle is formed between the first z-axis and the second radius, and the second radius increases as the second angle approaches 90.
11. The inverse shoulder prosthesis of claim 1, wherein the inlay has at least one radius around the second z-axis.
Description
DESCRIPTION OF DRAWINGS
[0018] In the following the invention will be described by way of example, without limitation of the general inventive concept, on examples of embodiment with reference to the drawings.
[0019] FIG. 1 shows a cross sectional view of an embodiment of the glenoid implant in the y.sub.1-z.sub.1 plane.
[0020] FIG. 2 shows a cross sectional view of an embodiment of the glenoid implant in the x.sub.1-z.sub.1 plane.
[0021] FIG. 3 shows a cross sectional view of an embodiment of a humerus implant.
[0022] FIG. 4 shows a cross sectional view of another embodiment of a humerus implant.
[0023] FIG. 5 shows a cross sectional view of embodiment of an inverse shoulder prosthesis in the y.sub.1-z.sub.1 (frontal plane).
[0024] FIG. 6 shows a cross sectional view in the x.sub.1-z.sub.1 plane (transversal plane) of another embodiment of an inverse shoulder prosthesis.
[0025] FIG. 7 shows a schematic view of a schematic view of a cross sectional view of an embodiment of an inverse shoulder prosthesis.
DETAILED DESCRIPTION
[0026] In FIG. 1 a cross sectional view of an embodiment of a glenoid implant 100 is shown. FIG. 1 shows a view of a glenoid implant 100 in the y.sub.1-z.sub.1 plane of an embodiment. The glenoid implant 100 may include a glenoid body 110, a first articulating surface 120, an attachment section 130 and an adapter 140. The glenoid body 110 may be convex. The first articulating surface 120 may be convex and dome shaped. The first articulating surface may have a first coordinate system (x.sub.1,y.sub.1,z.sub.1). The first coordinate system may have a first x-axis x.sub.1 152, a first y-axis y.sub.1 154, a first z-axis z.sub.1 156 and a first point of origin 158. The first articulating surface 120 may extend into the directions of the first x-axis x.sub.1 152, the first y-axis y.sub.1 154, and the first z-axis z.sub.1 156. The extension of the articulating surface 120 and therefore of the glenoid body 110 along the first y-axis y.sub.1 154 may be greater than the extension of the articulating surface 120 and therefore of the glenoid body 110 along the first x-axis x.sub.1 152. The glenoid body may be convex and may extend along the positive direction of the first z-axis z.sub.1 156. The first z-axis z.sub.1 156 may the center axis of the glenoid body 110. The first z-axis z.sub.1 156 may the center axis of the articulating surface 120. The first z-axis z.sub.1 156 may the center axis of the glenoid implant 100. The articulating surface 120 may have at least one first radius 162. The at least one first radius 162 may not vary in the z.sub.1-y.sub.1 plane. A first angle 172 may be located between the first z-axis z.sub.1 156 and the least one first radius 162. The first angle 172 may be 90 when z.sub.1 156=0 and 0 when y.sub.1 154=0. The first angle 172 may have a range of 180. The first angle 172 may have a range of at least 160. The first angle 172 may be 90 when y.sub.1 154=0 and 0 or 180 when z.sub.1 156=0. The first angle 172 may be 90 when y.sub.1 154=0 and 0 or at least 160 when z.sub.1 156=0. The glenoid body 110 may have a half spherical shape in the z.sub.1-y.sub.1 plane. The first articulating surface 120 may be the outer surface of the glenoid body 110. The glenoid implant 100 may have an attachment section 130 in the negative direction of the z-axis z.sub.1 156. The attachment section 130 may be connected to the glenoid body 110. Opposing to the first articulating surface 120 may be an attachment section 130 and an adapter 140. The attachment section 130 may be in a recess, for example a conical recess, adapted to hold the attachment section 130. The attachment section 130 may be connected to the glenoid body 110 by a loose or a fixed connection. The attachment section and the glenoid body may be monolithic, the attachment section may be part of the glenoid body. The adapter 140 may be connected to the glenoid body 110 opposing to the first articulating surface 120. The adapter 140 may be connected to the glenoid body 110 by a loose or a fixed connection.
[0027] FIG. 2 shows a cross sectional view of the glenoid implant 100 of the embodiment of FIG. 1 in the x.sub.1-z.sub.1 plane. The glenoid implant 100 may include a glenoid body 110, a first articulating surface 120, an attachment section 130 and an adapter 140. The first articulating surface 120 may have at least one second radius 164 in the x.sub.1-z.sub.1 plane. A second angle 174 may be located between the first z-axis z.sub.1 156 and the least one second radius 164. The second angle 174 may be 90 when z.sub.1=0 and 0 when x.sub.1 152=0. The second angle 174 may have a range of 180. The second angle 174 may have a range of at least 160. The second angle 174 may be 90 when x.sub.1 152=0 and 0 or 180 when z.sub.1=0. The second angle 174 may be 90 when x.sub.1 152 0 and 0 or at least 160 when z.sub.1=0. The at least one second radius 164 may vary depending on the second angle 174. The at least one second radius 164 may be smallest, when the second angle 174 is 0 (164.sub.1) and may be largest when the second angle 174 is 90 (164.sub.n). When 174 is 90, the at least one second radius 164 may correspond to the at least one first radius 162. In other words, when 174 is 90 the at least one second radius 164 and the at least one first radius 162 may be the same. The first articulating surface 120 may have the shape of a half ellipsoid and preferably of a half three-axial ellipsoid in the z.sub.1-x.sub.1 plane. The glenoid body 110 may have a half-ellipsoid, preferably of a half three-axial ellipsoid, cross sectional area in a plane defined by the first x-axis and the first z-axis.
[0028] In FIG. 3 a cross sectional view of an embodiment of a humerus implant 200 is shown. FIG. 3 shows a view of a humerus implant 200 in the y.sub.2-z.sub.2 plane of an embodiment. The humerus implant 200 may include prosthesis cup 210, an inlay 220 and a prosthesis stem 230. The inlay 220 may have a second articulating surface 225. The inlay 220 may have a concave shape. The inlay 220 may be located inside the prosthesis cup 210. The inlay 220 may be connected to the prosthesis cup 210 be a loose or fixed connection. The prosthesis cup 210 may be connected to the prosthesis stem 230. The prosthesis cup 210 may be connected to the prosthesis stem 230 by a loose or a fixed connection. The prosthesis cup 210 and the prosthesis stem 230 may be monolithic. The inlay 220 may have a second coordinate system (x.sub.2, y.sub.2, z.sub.2) with a second x-axis x.sub.2 252, a second y-axis y.sub.2 254, a second z-axis z.sub.2 256 and a second point of origin 258. The inlay 220 may extend into the directions of the second x-axis x.sub.2 252, the second y-axis y.sub.2 254, and the second z-axis z.sub.2 256. The second z-axis z.sub.2 256 may be the center axis of the inlay 220. The inlay 220 may extend into the negative direction of the second z-axis z.sub.2 256. The inlay 220 may have a second articulating surface 225. The inlay 220 may have at least one inner radius 262. The center of origin of the at least one inner radius 262 may be the point of origin of the second coordinate system. The at least one inner radius 262 may extend from the second point of origin to the second articulating surface 225. The inlay 220 may have at least a first inner radius and a second inner radius. The first inner radius may be located in a plane defined by the second x-axis x.sub.2 252 and the second z-axis z.sub.2 256. The second inner radius may be located in a plane defined by the second y-axis y1 154 and the second z-axis. The second inner radius may be smaller than the first inner radius.
[0029] In FIG. 4 a cross sectional view of another embodiment of a humerus implant 200 is shown. FIG. 4 shows a view of a humerus implant 200 in the x.sub.2-z.sub.2 plane. The humerus implant 200 may include prosthesis cup 212 and an inlay 220. The prosthesis cup 212 may be connected to prosthesis stem (not shown). The inlay 220 may have a second articulating surface 225. The inlay of this embodiment may correspond to the inlay of the embodiment of FIG. 3 in the x.sub.2-z.sub.2 plane.
[0030] FIG. 5 shows a cross sectional view of embodiment of an inverse shoulder prosthesis 300 in the y.sub.1-z.sub.1 (frontal plane). The inverse shoulder prosthesis 300 may include a glenoid implant 100 and a humerus implant 200. The glenoid implant 100 may include a glenoid body 110, a first articulating surface 120, an attachment section 130, at least one first radius 162, an adapter 140. The humerus implant 200 may include a prosthesis cup 210, an inlay 220, a second articulating surface 225, at least one inner radius 262 and a prosthesis stem 230. The glenoid body may have a half spherical cross section. The at least one first radius 162 may be a spherical radius. The at least one first radius 162 may match the inner radius 262. The first articulating surface 120 and the second articulating surface 225 may form a bearing. The matching radii may accomplish an angular rolling-movement in the y.sub.1-z.sub.1 plane. In an embodiment, the inner radius 262 may be 19.7 mm and the at least one first radius 162 may be 19.5 mm. The y.sub.1-z.sub.1 plane may be the frontal plane of the inverse shoulder prosthesis 300.
[0031] In FIG. 6 a cross sectional view in the x.sub.1-z.sub.1 plane (transversal plane) of another embodiment of an inverse shoulder prosthesis 300 is shown. The inverse shoulder prosthesis 300 may include a glenoid implant 100 and a humerus implant 200. The glenoid implant 100 may include a glenoid body 110, a first articulating surface 120, an attachment section 130, at least one second radius 164, an adapter 140. The humerus implant 200 may include a prosthesis cup 210, an inlay 220, a second articulating surface 225, at least one inner radius 262 and a prosthesis stem 230 (not shown). The at least one second radius 164 may be smaller than the at least one inner radius 262. There may be a mismatch between the at least one second radius 164 and the at least one inner radius 262 The mismatch may be in a range of 2.5 mm-7.5 mm. The mismatch may be in the transversal plane of the inverse shoulder prosthesis 300. This mismatch may allow an oscillation in the transversal plane. This oscillation may be a translational movement. The mismatch may enable a translational movement of the humerus implant 200 along the x-axes, resulting in a roll and glide movement of the inverse shoulder prosthesis 300. This mismatch may further enable an anatomically correct external and internal rotation of the inverse shoulder prosthesis 300. Furthermore, the mismatch may improve the axial rotation of the humerus implant 200. Due to the morphology of the glenoid body 110, a combined roll-slide mechanism may occur in the glenohumeral joint during rotation, while a roll-mechanism may occur during arm elevation due to the spherical shape of the glenoid body 110 in the y-z plane. In an embodiment, the inner radius 262 may be 19.7 mm and the at least one second radius 162 may be 17 mm.
[0032] FIG. 7 shows a schematic view of a schematic view of a cross sectional view of an embodiment of an inverse shoulder prosthesis 300. FIG. 7 shows the possible oscillation curve of the humerus implant 200. Due to the mismatch 400 between the radii of the inlay 220 and the first articulating surface 120, there may be a roll and glide movement of the joint. Due to this roll and glide movement, a greater range of motion of the prosthesis may be accomplished.
LIST OF REFERENCE NUMERALS
[0033] 100 glenoid implant [0034] 110 glenoid body [0035] 120 first articulating surface [0036] 130 attachment section [0037] 140 adapter [0038] 152 first x-axis/x.sub.1 [0039] 154 first y-axis/y.sub.1 [0040] 156 first z-axis/z.sub.1 [0041] 158 first point of origin [0042] 162 first radius [0043] 164 second radius [0044] 172 first angle [0045] 174 second angle [0046] 200 humerus implant [0047] 210 humeral body [0048] 212 prosthesis cup [0049] 220 inlay [0050] 225 second articulating surface [0051] 230 prosthesis stem [0052] 252 second x-axis/x.sub.2 [0053] 254 second y-axis/y.sub.2 [0054] 256 second z-axis/z.sub.2 [0055] 258 second point of origin [0056] 262 inlay radius [0057] 300 inverse shoulder prosthesis [0058] 400 Mismatch
