Temporomandibular joint prosthesis and kit consisting of two temporomandibular joint prostheses

Abstract

The invention relates to a temporomandibular joint prosthesis (90, 902) comprising a first element (30, 302) that can be fastened to a first side of the lower jaw (40) and a second element (80, 802) that can be fastened to the first side of the cranium (50), wherein a joint head (42, 422) is formed at one end of the first element (30, 302), wherein a joint surface (82) is formed on the second element (80, 802), said joint surface forming an abutment of the joint head (42, 302), wherein the joint head (42, 422) and the joint surface (82, 822) predefine a rotational axis (A1, A2), wherein the first element (30, 302) and the second element (80, 802) are shaped such that, in the implanted state, the rotational axis (A1, A2) is pre-oriented at an angle to a frontal plane (F) of the patient. The invention also relates to a kit (K) consisting of two such temporomandibular joint prostheses (90, 902).

Description

[0001] Karl Leibinger Asset Management KLS0057P-WO GmbH & Co. KG 2025-09-03

[0002] - 1 -

[0003] Temporomandibular joint prosthesis and kit of two temporomandibular joint prostheses

[0004] The invention relates to a temporomandibular joint prosthesis, as well as a kit consisting of a first and a second such temporomandibular joint prosthesis.

[0005] The temporomandibular joint (TMJ) is one of the most frequently used joints in the human body. It plays a crucial role in the movement of the mandible (lower jaw), chewing, speaking, swallowing, and stress management. It is even constantly in motion during sleep due to the swallowing motion. For the TMJ to perform its movements, the shape of the articular surfaces, the condition of the teeth, tooth position, tooth shape, and the masticatory muscles must form a functional system. Due to the multitude of components, the TMJ is somewhat susceptible to dysfunction. The left and right TMJs always work together, forming a functional unit.

[0006] However, if disorders occur in the area of ​​the temporomandibular joint, such as...

[0007] Functional limitations or diseases can impair a patient's quality of life in everyday situations. Restoring proper joint structure is usually only possible through surgery, i.e., by resection of the affected joint and its replacement with a temporomandibular joint prosthesis.

[0008] From EP 2 114 309 A1 a prosthesis for use in the temporomandibular joint for connecting the mandibular bone to the temporal bone on the side of the skull is known.

[0009] The temporomandibular joint (TMJ), together with the geometry of the mandible and maxilla, defines the occlusion. Occlusion, in this context, refers to the contact between the teeth of the mandible and the teeth of the maxilla when the jaws are closed naturally. Therefore, when restoring the TMJ, it is crucial to ensure that the occlusion is not negatively affected or is improved as desired.

[0010] The object of the invention is therefore to provide a temporomandibular joint prosthesis with which a desired occlusion can be reliably achieved. Karl Leibinger Asset Management KLS0057P-WG GmbH & Co. KG 2025-09-03

[0011] - 2 -

[0012] The problem is solved by the features of claim 1. Advantageous embodiments result from the dependent claims, the description and the figures.

[0013] To solve the problem, a temporomandibular joint prosthesis with a first element and a second element is specified. The first element can be attached to the first side of the mandible and has a suitable shape for this purpose. The second element can be attached to the first side of the cranium and has a suitable shape for this purpose. A condylar head is formed at one end of the first element. An articular surface is formed on the second element, which provides a counter-surface for the condylar head.

[0014] The condyle and articular surface replicate the temporomandibular joint (TMJ) accordingly, such that they predefine an axis of rotation. A "predefining axis of rotation" in this context means that the axis of rotation is pre-defined but still possesses multiple degrees of freedom. In other words, the condyle and articular surface do not define a rigid axis of rotation that is fixed as a single degree of freedom for the joint. The first and second elements are shaped such that, in the implanted state, the axis of rotation is oriented obliquely to a frontal plane of the patient. The invention is based on the understanding that an axis of rotation oriented obliquely to the frontal plane results in an overdetermination of the overall axis of rotation of the mandible relative to the maxilla, which is helpful for improving occlusion.

[0015] Preferably, the axis of rotation in the implanted state has an angle of 10 to 25 degrees to the patient's frontal plane, more preferably an angle of 12 to 20 degrees, and most preferably an angle of 15 to 20 degrees. These angular ranges have proven advantageous for improving occlusion in simulations.

[0016] Preferably, the first and second elements are shaped specifically for the patient, for example, based on 3D scan data. This allows the unique anatomy to be taken into account when designing the first and second elements, making the occlusion particularly predictable and allowing it to be considered accordingly during the planning and fabrication of the temporomandibular joint prosthesis. Karl Leibinger Asset Management KLS0057P-WG GmbH & Co. KG 2025-09-03

[0017] - 3 -

[0018] If both temporomandibular joints (TMJs) need to be replaced, a kit consisting of a first and a second TMJ prosthesis is preferably used. The first TMJ prosthesis is designed to replace the TMJ on one side of the body. The second TMJ prosthesis is designed to replace the TMJ on the opposite side of the body. Both the first and second TMJ prostheses are designed as described above.

[0019] Preferably, the first and second elements of the first temporomandibular joint prosthesis in the kit are shaped such that the axis of rotation of the first prosthesis, when implanted, is pre-aligned at a first angle to the frontal plane. The first and second elements of the second temporomandibular joint prosthesis in the kit are shaped such that the axis of rotation of the second prosthesis, when implanted, is pre-aligned at a second angle to the frontal plane. The first and second angles are either equal or differ from each other by a maximum of five degrees. Simulations have shown that such an alignment of the first and second angles is advantageous for improving occlusion.

[0020] Preferably, the articular surface of the first temporomandibular joint prosthesis has the same shape as the articular surface of the second temporomandibular joint prosthesis. Alternatively or additionally, the condyle of the first temporomandibular joint prosthesis can have the same shape as the condyle of the second temporomandibular joint prosthesis. In other words, the pre-alignment of the respective axis of rotation is achieved not by the joint geometry itself, but by the alignment of the joint geometry. The identical joint geometry is clearly recognizable to the surgeon, allowing for minor intraoperative adjustments to the alignment.

[0021] Alternatively, the articular surface of the first temporomandibular joint prosthesis can have a different shape than the articular surface of the second temporomandibular joint prosthesis. Alternatively or additionally, the condyle of the first temporomandibular joint prosthesis can have a different shape than the condyle of the second temporomandibular joint prosthesis. In other words, the pre-alignment of the respective axis of rotation is additionally implemented through the joint geometry. Karl Leibinger Asset Management KLS0057P-WG GmbH & Co. KG 2025-09-03

[0022] - 4 -

[0023] Exemplary embodiments of the invention are described in detail with reference to the figures. The figures show:

[0024] Figs. 1 and 2 each show an isometric view of a temporomandibular joint prosthesis on a skull bone.

[0025] Fig. 3 is a schematic view from below of a kit consisting of two temporomandibular joint prostheses, and Fig. 4 is a schematic view from below of a

[0026] Temporomandibular joint prosthesis.

[0027] Fig. 1 shows an isometric view of a temporomandibular joint prosthesis 90, which connects a segment of the left half of the mandible 40 to the left side of the cranium 50, thus replicating the function of the natural left temporomandibular joint. The temporomandibular joint prosthesis 90 has a first element 30, which is attached to the mandible 40 at its distal end. The first element 30 has a corresponding geometry, in the example shown in Fig. 1, in the form of a structure following the anatomy of the mandible 40, with several holes for receiving screws (not shown in Fig. 1). At one end, the first element 30 has a condylar head 42. The condylar head 42 is received in an articular surface 82, which is part of a second element 80 of the temporomandibular joint prosthesis 90. The second element 80 is attached to the cranium 50 by several screws (not shown in Fig. 1).The condylar head 42 and articular surface 82 do not form a fixed axis of rotation for the mandible 40 relative to the cranium 50. Instead, the condylar head 42 and articular surface 82 form a joint geometry that, similar to the natural temporomandibular joint, has several degrees of freedom for movement. In the implanted state, the condylar head 42 is held in the articular surface 82 by muscles and tendons (not shown in Fig. 1).

[0028] Fig. 2 shows an isometric view of a temporomandibular joint prosthesis 902, which connects a segment of the right mandibular half 40 to the right side of the cranium 50, thus replicating the function of the natural right temporomandibular joint. The temporomandibular joint prosthesis 902 has essentially the same structure as the temporomandibular joint prosthesis 90 shown in Fig. 1, and accordingly comprises a first element 302 and a second element 802. The first element 302 is attached to the mandible 40 at one end. At the opposite end, the first element 302 has a condylar head 422. Karl Leibinger Asset Management KLS0057P-WO GmbH & Co. KG 2025-09-03

[0029] - 5 - The second element 802 is attached to the cranium 50 by several screws, not shown in Fig. 2. The condylar head 422 is received in an articular surface 822, which is part of the second element 802 of the temporomandibular joint prosthesis 902. The condylar head 422 and the articular surface 822 do not form a fixed axis of rotation for the rotation of the mandible 40 relative to the cranium 50. Instead, the condylar head 422 and the articular surface 822 form an articular geometry that, similar to the natural temporomandibular joint, has several degrees of freedom for movement. In the implanted state, the condylar head 422 is held in the articular surface 822 by muscles and tendons, not shown in Fig. 2.

[0030] Fig. 3 shows a schematic, not-to-scale, bottom view of a kit K, consisting of the temporomandibular joint prostheses 90, 902 shown in Figs. 1 and 2. The representation in Fig. 3 clearly shows that the condylar head 42, 422 and articular surface 82, 822 of the respective temporomandibular joint prosthesis 90, 902 are oriented obliquely to the frontal plane F of the patient. The oblique orientation of the condylar head 42 and the articular surface 82 at the angle W1 to the frontal plane F pre-aligns an axis of rotation A1 of the temporomandibular joint prosthesis 90. Similarly, the oblique orientation of the condylar head 422 and the articular surface 822 at the angle W2 to the frontal plane F pre-aligns an axis of rotation A2 of the temporomandibular joint prosthesis 902. This pre-alignment results in an overdetermination of the mandibular rotation relative to the cranium 50 (not shown in Fig. 3), which improves the occlusion. In the embodiment shown in Fig. 3, angles W1 and W2 are equal.In individual cases, a slight deviation of the angles W1, W2 can be chosen.

[0031] Kit K, consisting of the two temporomandibular joint prostheses 90 and 902, is used when both temporomandibular joints need to be replaced. If only one of the two temporomandibular joints needs to be replaced, the healthy temporomandibular joint preferably remains in the patient. Fig. 4 shows a schematic, not-to-scale, bottom view of a single temporomandibular joint prosthesis 90 for such a case, in which the healthy temporomandibular joint (shown on the right in Fig. 4) remains in the patient. The first and second elements 30 and 80 of the temporomandibular joint prosthesis 90 are shaped such that the axis of rotation A1 is obliquely forward-oriented to a frontal plane F when implanted. Karl Leibinger Asset Management KLS0057P-WG GmbH & Co. KG 2025-09-03

[0032] - 6 -

[0033] Reference symbol list

[0034] 90, 902 Temporomandibular joint prosthesis

[0035] 30, 302 First element

[0036] 80, 802 Second Element

[0037] 42, 422 Joint head

[0038] 82, 822 articulating surface

[0039] A1, A2 axis of rotation

[0040] W1, W2 angles

[0041] F Frontal plane

[0042] 40 Lower jaw

[0043] 50 Cranium

[0044] K Kit

Claims

Karl Leibinger Asset Management KLS0057P-WG GmbH & Co. KG 2025-09-03 - 7 - Patent claims 1. Temporomandibular joint prosthesis (90, 902) comprising a first element (30, 302) attachable to a first side of the mandible (40) and a second element (80, 802) attachable to the first side of the cranium (50), wherein a condylar head (42, 422) is formed at one end of the first element (30, 302), wherein an articular surface (82) is formed on the second element (80, 802) which forms a counter-bearing of the condylar head (42), wherein the condylar head (42, 422) and the articular surface (82, 822) predefine an axis of rotation (A1, A2), characterized in that the first element (30, 302) and the second element (80, 802) are shaped such that the axis of rotation (A1, A2) is oblique to a frontal plane (F) of the implanted state. It is patient-oriented.

2. Temporomandibular joint prosthesis (90, 902) according to claim 1, characterized in that the axis of rotation (A1, A2) in the implanted state has an angle (W1, W2) of 10 to 25 degrees to the frontal plane (F) of the patient, preferably an angle (W1, W2) of 12 to 20 degrees, particularly preferably an angle (W1, W2) of 15 to 20 degrees.

3. Temporomandibular joint prosthesis (90, 902) according to claim 1 or claim 2, characterized in that the first element (30, 302) and the second element (80, 802) are shaped to be patient-specific.

4. Kit (K) comprising a first temporomandibular joint prosthesis (90) according to one of claims 1 to 3 and a second temporomandibular joint prosthesis (902) according to one of claims 1 to 3, wherein the first temporomandibular joint prosthesis (90) is configured to replace the temporomandibular joint on a first side of the body and the second temporomandibular joint prosthesis (902) is configured to replace the temporomandibular joint on a second side of the body opposite the first side of the body.

5. Kit (K) according to claim 4, characterized in that the first and second elements (30, 80) of the first temporomandibular joint prosthesis (90) are shaped such that the axis of rotation (A1) of the first temporomandibular joint prosthesis (90) is pre-aligned in the implanted state at a first angle (W1) to the frontal plane (F), wherein the first and second elements (302, 802) of the second temporomandibular joint prosthesis (902) are shaped such that the axis of rotation (A2) of the second Karl Leibinger Asset Management KLS0057P-WG GmbH & Co. KG 2025-09-03 - 8 - The temporomandibular joint prosthesis (902) in the implanted state is pre-aligned at a second angle (W2) to the frontal plane (F), wherein either the first angle (W1) is equal to the second angle (W2), or the first angle (W1) and the second angle (W2) differ from each other by a maximum of five degrees.

6. Kit (K) according to claim 4 or claim 5, characterized in that the articulating surface (82) of the first temporomandibular joint prosthesis (90) has the same shape as the articulating surface (822) of the second temporomandibular joint prosthesis (902), and / or the articulating head (42) of the first temporomandibular joint prosthesis (90) has the same shape as the articulating head (422) of the second temporomandibular joint prosthesis (902).

7. Kit (K) according to claim 4 or claim 5, characterized in that the articulating surface (82) of the first temporomandibular joint prosthesis (90) has a different shape than the articulating surface (822) of the second temporomandibular joint prosthesis (902), and / or the articulating head (42) of the first temporomandibular joint prosthesis (90) has a different shape than the articulating head (422) of the second temporomandibular joint prosthesis (902).

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