Prosthetic Component

Abstract

A prosthetic component (2) adapted to be mounted to a bone as part of a knee prosthesis comprises a spacing element for compensating resected bone. The prosthetic component (2) further comprises a main body (6) with a contact surface (7) configured to abut the spacing element and a fixation mechanism (9) for fixing the spacing element between the contact surface (7) and the bone.

The fixation mechanism (9) comprises a receiving portion (10) located at the contact surface (7). The fixation mechanism (9) further comprises an insert (11) for insertion into the receiving portion (10) and a fastening element adapted to engage with the insert (11). The receiving portion (10) is adapted to fix the insert (11) via a bayonet joint connection such that the fastening element, extending through the spacing element and engaging with the insert (11), fixes the spacing element to the contact surface (7).

Claims

1. Prosthetic component adapted to be mounted to a bone as part of a knee prosthesis, the prosthetic component comprising: a spacing element for compensating resected bone, a main body with a contact surface configured to abut the spacing element and a fixation mechanism for fixing the spacing element between the contact surface and the bone, wherein: the fixation mechanism comprises: a receiving portion located at the contact surface, an insert for insertion into the receiving portion and a fastening element adapted to engage with the insert, and wherein the receiving portion is adapted to fix the insert via a bayonet joint connection such that the fastening element, extending through the spacing element and engaging with the insert, fixes the spacing element to the contact surface.

2. Prosthetic component according to claim 1, wherein the insert has a cylindrical shape and comprises multiple protrusions which extend radially outward.

3. Prosthetic component according to claim 1, wherein the protrusions extend in opposing directions.

4. Prosthetic component according to claim 1, wherein the receiving portion comprises a non-cylindrical receiving opening which allows insertion of the insert into the receiving portion in a first position of the insert.

5. Prosthetic component according to claim 1, wherein the receiving portion comprises undercuts which are configured to prevent removal of the insert from the receiving portion in a second position of the insert.

6. Prosthetic component according to claim 2, wherein the receiving portion is configured such that upon movement of the insert from the first position into the second position the protrusions of the insert are brought into engagement with the undercuts of the receiving portion and the bayonet joint connection between the receiving portion and the insert is established.

7. Prosthetic component according to claim 6, wherein the second position is offset from the first position by an angle of between 80° and 100° around an axis of rotation which extends normal to the contact surface.

8. Prosthetic component according to claim 1, wherein the receiving portion is formed as a blind hole.

9. Prosthetic component according to claim 1, wherein the insert is a threaded insert and the fastening element is a screw.

10. Prosthetic component according to claim 1, wherein the prosthetic component is a tibial component and the bone to which the prosthetic component is adapted to be mounted is a tibia.

11. Prosthetic component according to claim 10, wherein the tibial component has an inlay receiving surface located opposite the contact surface, wherein the inlay receiving surface is adapted to abut an inlay which is configured to articulate with a femoral component in a knee prosthesis.

12. Prosthetic component according to claim 1, wherein the prosthetic component is a femoral component and the bone to which the prosthetic component is adapted to be mounted is a femur.

13. Knee prosthesis comprising a prosthetic component according to claim 1.

14. Prosthetic component according to claim 2, wherein the receiving portion comprises a non-cylindrical receiving opening which allows insertion of the insert into the receiving portion in a first position of the insert.

15. Prosthetic component according to claim 3, wherein the receiving portion comprises a non-cylindrical receiving opening which allows insertion of the insert into the receiving portion in a first position of the insert.

16. Prosthetic component according to claim 4, wherein the receiving portion is configured such that upon movement of the insert from the first position into the second position the protrusions of the insert are brought into engagement with the undercuts of the receiving portion and the bayonet joint connection between the receiving portion and the insert is established.

17. Prosthetic component according to claim 5, wherein the receiving portion is configured such that upon movement of the insert from the first position into the second position the protrusions of the insert are brought into engagement with the undercuts of the receiving portion and the bayonet joint connection between the receiving portion and the insert is established.

18. Prosthetic component according to claim 6, wherein the second position is offset from the first position by an angle of 90° around an axis of rotation which extends normal to the contact surface.

19. Prosthetic component according to claim 16, wherein the second position is offset from the first position by an angle of 90° around an axis of rotation which extends normal to the contact surface.

20. Prosthetic component according to claim 17 wherein the second position is offset from the first position by an angle of 90° around an axis of rotation which extends normal to the contact surface.

Description

[0025] The invention will now be described in connection in one exemplary embodiment shown in the Figures in which:

[0026] FIG. 1 shows a knee prosthesis in an isometric view,

[0027] FIG. 2 shows a perspective view of a tibial component with an insert,

[0028] FIG. 3 shows a sectional view of the insert of FIG. 2 inserted into a receiving portion,

[0029] FIG. 4 shows a perspective view of the tibial component of FIG. 2 together with a spacing element,

[0030] FIG. 5 shows a sectional view of the tibial component of FIG. 4 and a fixation mechanism and

[0031] FIG. 6 shows a sectional view of a tibial component of FIG. 5 together with a spacing element being fixed to the tibial component.

[0032] FIG. 1 shows a knee prosthesis 1 with a first prosthetic component formed as a tibial component 2, a second prosthetic component formed as a femoral component 3 and an inlay 4. The tibial component 2 and the femoral component 3 are adapted to be mounted onto a tibia (not shown) and a femur (not shown), respectively. The inlay 4 is located between the femoral component 3 and the tibial component 2 and is fixed to the latter. The femoral component 3 is adapted to articulate with the inlay 4 to allow a flexion of the knee prosthesis 1.

[0033] FIGS. 2 to 4 show the tibial component 2 in detail. The tibial component 2 comprises a spacing element 5 for compensating resected bone, in particular tibial bone. The tibial component 2 further comprises a main body 6 with a contact surface 7 configured to abut the spacing element 5 and an inlay receiving surface 8 located opposite the contact surface 7. The inlay receiving surface 8 is adapted to abut the inlay 4.

[0034] The tibial component 2 further comprises a fixation mechanism 9 for fixing the spacing element 5 to the main body 6. The fixation mechanism 9 includes a receiving portion 10 located at the contact surface 7, a threaded insert 11 for insertion into the receiving portion 10 and a fastening element formed as a screw 12. The screw 12 is adapted to be inserted into a throughole 21 extending through the spacing element 5 and to engage with the threaded insert 11. The insert 11 has a cylindrical shape and comprises two protrusions 13 extending radially outward in opposing directions at a lower end 23 of the insert 11. The protrusions 13 form an oval base 24 of the insert 11.

[0035] The receiving portion 10 is formed as a blind hole 14 which has a receiving opening 15 at the contact surface 7. The opening 15 is non-cylindrical, in particular oval, and allows insertion of the insert into the receiving portion 10 in a first position of the insert 11 (as shown in FIG. 2). The shape of the opening 15 corresponds to the shape of the oval base 24 of the insert 11.

[0036] The receiving portion 10 comprises undercuts 16, which are configured to prevent removal of the insert 11 from the receiving portion 10 in a second position of the insert 11 (as shown in FIG. 3) in a direction normal to the contact surface 7. The second position is off-set from the first position by an angel of 90 degrees around an axis of rotation 17 which extends normal to the contact surface 7. In order to move the insert 11 from the first position to the second position the insert 11 has to be turned clockwise along arrow A around the axis of rotation 17.

[0037] The contact surface 7 comprises opposing first markings 18 located in proximity to the receiving portion 10. The insert 11 comprises corresponding second markings 19 at its top end 20. The first and second markings 18, 19 are configured such that upon alignment of the first markings 18 with the second markings 19 the insert is in its second position (as shown in FIG. 3).

[0038] The receiving portion 10 is further configured such that upon movement of the insert 11 from the first position (as shown in FIG. 2) into the second position (as shown in FIG. 3) the protrusions 13 of the insert 11 are brought into engagement with the undercuts 16 of the receiving portion 10 and the bayonet joint connection between the receiving portion 10 and the insert 11 is established. Removal of the insert 11 from the receiving portion 10 in a direction normal to the contact surface 7 is prevented.

[0039] As can be seen in FIGS. 4 to 6 the screw 12 extends through the throughhole 21 of the spacing element 5 and engages with the threaded insert 11. The receiving portion 10 is further configured such that upon tightening of the screw 12 against the spacing element 5 the insert 11 is lifted along arrow B from a bottom 22 of the blind hole 14 towards the undercuts 16 of the receiving portion until the protrusions 13 of the insert 11 abut the undercuts 16 of the receiving portion 10. In other words, the receiving portion 10 is adapted to fix the insert 11 via a bayonet joint connection such that the screw 12, extending through the spacing element 5 and engaging with the insert 11, fixes the spacing element 5 to the contact surface 7.

REFERENCE NUMERALS

[0040] 1 knee prosthesis [0041] 2 tibial component (first prosthetic component) [0042] 3 femoral component (second prosthetic component) [0043] 4 inlay [0044] 5 spacing element [0045] 6 main body [0046] 7 contact surface [0047] 8 inlay receiving surface [0048] 9 fixation mechanism [0049] 10 receiving portion [0050] 11 insert [0051] 12 fastening element [0052] 13 protrusions [0053] 14 blind hole [0054] 15 receiving opening [0055] 16 undercuts [0056] 17 axis of rotation [0057] A arrow [0058] 18 first markings [0059] 19 second markings [0060] 20 top end [0061] 21 through hole [0062] 22 bottom [0063] B arrow [0064] 23 lower end (insert) [0065] 24 oval base (insert)