Prosthetic device for the temporomandibular joint and corresponding prosthetic assembly - Patents.com

Abstract

The prosthesis (10) for a temporomandibular joint comprises a first prosthetic element (11) connectable to a patient's mandibular condyle (112) and a corresponding second prosthetic element (12) connectable to a respective mandibular condyle of the patient. The invention also relates to a guide device (35) for creating an anchor seat (113) for positioning the first element, and a prosthetic assembly comprising the prosthesis (10) and the guide device (35).

Description

[Technical field]

[0001] The present invention relates to a prosthesis for the temporomandibular joint and to a corresponding prosthetic assembly comprising said prosthesis and a guide device for the preparation of a suitable bone seat. The above-described prostheses are particularly suitable for application in patients with non-extensive joint pathologies, for example in cases of osteoarthritis / osteoarthritis, condylar resorption, benign tumors, or where surgery has failed.

[0002] This solution may also be employed as the primary procedure in many patients where the traditional route would involve other attempts at functional joint arthroplasty, which usually end in failure. [Background technology]

[0003] Remodeling the temporomandibular joint is known to be problematic due to the complex role it plays within the stomatognathic system. The temporomandibular joint plays an essential role in chewing, speaking, supporting respiratory exchange, and swallowing, and is a secondary growth point in the jaw during prepuberty. Furthermore, the temporomandibular joint undergoes repeated cycles of loading / unloading more than any other joint in the body.

[0004] Due to the anatomical and biomechanical complexities of the temporomandibular joint, surgical procedures to correct the problem and associated pathologies are complex and currently highly invasive. The temporomandibular joint connects the mandible to the temporal bone, and in particular, connects the mandibular condyle to the mandibular fossa of the temporal bone.

[0005] A prosthesis for the temporomandibular joint therefore comprises two components, a condyle prosthesis and a mandibular fossa prosthesis, which in use are associated with the mandibular condyle and the mandibular fossa of the temporal bone, respectively, both components being made according to the specific requirements of the patient and his / her anatomy.

[0006] Before the application of these components, it is necessary to carry out a bone orthopedic procedure to prepare the condyle and the mandibular fossa to accommodate the respective prosthesis. For this purpose, guide devices may be provided that can facilitate the bone resection procedure carried out by the surgeon. Furthermore, it is necessary to use a conventional surgical burr, which causes scars (sometimes quite extensive) in and around the affected bone tissue.

[0007] Currently used prostheses are very bulky and require a very large installation space between the ramus and the base of the skull (necessary to allow insertion of the fossa and condylar prostheses), which often makes orthodontic surgery of the condyle (and mandibular fossa, if required) very extensive and invasive.

[0008] This limits the indication for prosthetic joint implants to only the most severe cases. The size of the current prostheses also makes the surgical procedure very invasive (an incision in front of the ear for insertion of the mandibular fossa prosthesis and an incision behind the jaw for insertion of the ramus / condyle prosthesis).

[0009] The invasive nature of current prosthetic devices and the surgical procedures for their installation lead to long patient hospital stays and potential complications. Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, a need exists for a complete prosthesis for application to the temporomandibular joint and corresponding prosthetic assembly that can overcome one or more of the shortcomings in the current art. In particular, one object of the present invention is to provide a prosthesis for the temporomandibular joint which can be implanted requiring only limited bone correction of the condyle (and possibly of the mandibular fossa).

[0011] Another object of the present invention is to provide a prosthesis for the temporomandibular joint that allows for the extension of surgical indications, and therefore applicability, to a larger number of patients compared to the use of conventional prostheses.

[0012] Another object of the present invention is to provide a temporomandibular joint prosthesis that is made of a limited number of components to simplify and speed its installation. Another object of the present invention is to provide a prosthetic assembly for the temporomandibular joint which is advantageously customised / personalised and patient specific, whilst simplifying the corresponding surgical technique and making it less invasive.

[0013] Applicant has conceived, tested and embodied the present invention to overcome the shortcomings of the current art and to obtain these and other objects and advantages. [Means for solving the problem]

[0014] The invention is set forth and characterized in the independent claims. The dependent claims describe further features of the invention and variants relative to the main inventive concept. In accordance with the above objectives, a temporomandibular joint prosthesis that overcomes the limitations of current technology and eliminates the drawbacks existing therein comprises a first prosthetic member connectable to a patient's mandibular condyle and a corresponding second prosthetic member connectable to a respective mandibular condyle cavity of the patient.

[0015] The first prosthetic component is configured to cooperate with the second prosthetic component to form the temporomandibular joint, and includes a protrusion that cooperates with the second prosthetic component to form the temporomandibular joint. In one aspect of the invention, the first prosthetic component comprises one or more anchor elements projecting from and attached to the recess, the anchor elements being received in the recess and having a main extension along a lateral-medial axis, the anchor elements being configured to be inserted into an engagement anchor seat present (or provided) on the mandibular condyle, and the engagement seat being at least partially open along the lateral-medial axis.

[0016] In this way, the first prosthetic element can be easily inserted in a direction parallel to the lateral-medial axis, making it possible to limit the removal of bone material from the patient to a minimum and at the same time greatly simplifying the surgical procedure. In addition, the minimal invasiveness of the surgical procedure and the resection of the condyle allows an extension of the surgical indication and therefore a much greater applicability compared to the use of conventional prosthetic devices.

[0017] In some embodiments, the first prosthetic component comprises a recess forming a mating seat having a shape that engages with the shape of the mandibular condyle, the recess being configured to cooperate with the second prosthetic component to form the temporomandibular joint, and the protrusion facing the recess.

[0018] In some embodiments, a guide device is provided for preparing an anchor seat for the prosthesis, particularly for positioning a first prosthesis component. The guide device comprises a central body positionable against at least the upper lateral part of the ramus, and a guide wall connected to the central body at its upper part and having a profile of the osteotomy to be performed on the condyle.

[0019] In one particular aspect of the invention, the guide device has a groove extending vertically towards the central body, the groove being open at the top and opening in a direction parallel to the lateral-medial axis.

[0020] Some embodiments of the invention include a prosthetic assembly, which is advantageously customized and patient-specific, provided with the prosthesis and corresponding guide device. [Brief description of the drawings]

[0021] [Figure 1] 1 is a perspective view of a temporomandibular joint prosthesis according to an embodiment described herein; FIG. [Diagram 2] FIG. 2 is a perspective view of the first prosthetic element of FIG. 1; [Diagram 3] FIG. 2 is a perspective view of the second prosthetic element of FIG. 1; [Figure 4] FIG. 3 is a side view of the anchor element of FIG. 2 . [Diagram 5] FIG. 2 is a perspective view showing the connection between the first prosthetic component and the mandibular condyle. [Figure 6] FIG. 2 is an exterior plan view of the first prosthetic component in use. [Figure 7] FIG. 1 is an inner plan view of a first prosthetic component in use; [Figure 8] FIG. 2 is a front view of the first prosthetic component in use. [Figure 9] 1 is a perspective view of a guide device according to embodiments described herein. [Figure 10] FIG. 10 is a perspective view showing the function of the guide device in FIG. 9 . [Figure 11] FIG. 10 is a perspective view showing the function of the guide device in FIG. 9 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] These and other aspects, features and advantages of the present invention will become apparent from the following description of some embodiments thereof, given by way of non-limiting example with reference to the attached drawings, in which:

[0023] To facilitate understanding, the same reference numbers are used, where possible, to identify identical common elements in the drawings. It will be understood that, for convenience, elements and features of one embodiment may be incorporated in other embodiments without further description.

[0024] Reference will now be made in detail to possible embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided for the purpose of illustrating the invention and is not to be understood as a limitation of the invention. For example, one or more features illustrated or described as part of one embodiment can be modified, adapted to, or associated with other embodiments to produce another embodiment. It is to be understood that the invention includes all such modifications and variations.

[0025] Before describing these embodiments, it should also be made clear that this description is not intended to limit the present application with respect to the details of the construction and arrangement of the components, as set forth in the following detailed description with accompanying drawings. Other embodiments are possible from this description and can be obtained or carried out in various other ways. It should also be made clear that the phraseology and terminology used herein are for the purpose of description only and should not be regarded as limiting.

[0026] Some embodiments described herein relate to a temporomandibular joint prosthesis 10 (FIGS. 1-7) and a guide device 35 (FIGS. 9-11) necessary to prepare a particular anchor seat 113 (FIG. 11) for the prosthesis 10, as described in more detail below. Other embodiments also include a prosthetic assembly, which is advantageously customized / personalized and patient-specific, and includes the prosthesis 10 and the guide device 35.

[0027] Hereinafter, the terms proximal, distal, anterior, posterior, medial, and lateral are defined as standardly used by those skilled in the art to denote particular planes or orientations with respect to bones, anatomical parts, prosthetic devices and components thereof, or other elements, according to reference to natural anatomical relative positions, or directional terms relative thereto, of the human and / or animal body.

[0028] With particular reference to FIG. 1, the temporomandibular joint connects the mandible 111 to the temporal bone 110, and in particular connects the mandibular condyle (FIG. 5; hereinafter, condyle) 112 to the mandibular glenoid fossa (hereinafter, glenoid fossa) of the temporal bone 110.

[0029] The prosthesis 10 thus comprises a first prosthetic member 11 connectable to a patient's condyle 112 and a corresponding second prosthetic member 12 connectable to a respective glenoid cavity of the patient. In particular, the condyle 112 is suitably shaped to receive the first prosthetic member 11, as described in more detail below.

[0030] The first prosthetic part 11 comprises a recess 13 forming a coupling seat 14 having a shape that engages with the shape of the condyle 112 shaped as described above. The first member 11 includes a protruding portion 15 facing the recessed portion 13. The protruding portion 15 is configured to be coupled to the second prosthetic member 12 to form a temporomandibular joint.

[0031] The first prosthetic component 11 includes one or more anchor elements 16 that protrude from and are attached to at least the recess 13. The anchor elements 16 have an overall size to be substantially received within the recess 13.

[0032] The anchor element 16 has a main extension along a latero-medial axis X. In particular, hereinafter, the term "later-medial" is intended to indicate a direction from a lateral region towards a region located in the adjacent part of the medial plane of the patient's body.

[0033] The anchor element 16 is configured to be inserted into an engaging anchor seat 113 (FIG. 11) created on the patient's condyle 112 which is shaped to follow the profile of the guide device 35, as described below.

[0034] The coupling seat 14 is at least partially open along the lateral-medial axis X to allow coupling of the first prosthetic component 11 and the condyle 112 in a direction parallel to the lateral-medial axis (extending from the outside to the inside) in one possible application (FIGS. 2, 5 and 7-8). In the embodiment described herein, the coupling seat 14 has a shape that substantially engages the connecting upper portion of the condyle 112.

[0035] The specific geometry of the prosthesis 10, and in particular of the first prosthesis part 11 with its anchor elements 16 inserted in an lateral-medial direction, makes it possible to limit the removal of bone material from the patient to a minimum, and at the same time to greatly simplify and make the surgical procedure less invasive, since only one access route has to be made, via an incision in front of the ear.

[0036] In some embodiments described herein, particularly with reference to Figures 2, 5 and 8, the first prosthetic element 11 further comprises an external lateral portion 17 configured to be coupled laterally to the condyle 112. The external lateral portion 17 has an extension, such as to allow for lateral abutment during positioning of the first prosthetic element 11 along the lateral-medial axis X and to allow fixation thereof.

[0037] The first prosthetic element 11 can be configured as a condyle prosthesis, which is configured to at least partially cover the patient's condyle 112. This first prosthetic element 11 is envisaged as a cover prosthesis, the purpose of which is to preserve as much as possible the original bone part of the condyle 112. Preferably, this condyle prosthesis can be used in cases of non-diffuse pathologies, which in fact are the most common occurrence of such pathologies.

[0038] In particular, the first prosthetic element 11 is configured to cover the lateral, upper (usually connected to the fossa) and possibly the anterior and posterior surfaces of the condyle 112. As is evident, in the mode of insertion of the first prosthetic element 11, i.e. in a direction parallel to the lateral-medial axis X, it is not provided to cover the medial part of the condyle 112 (FIGS. 7-8).

[0039] 2, the first prosthetic element 11 comprises an outer shell 18 having an upper wall 19 and an outer lateral wall 20 arranged at an incline relative to the upper wall 19. The inclination of the outer lateral wall 20 is essentially given by the anatomy of the patient's ramus 114. In the example embodiment described herein, this inclination is approximately 90° or slightly less.

[0040] The upper wall 19 is shaped such that it forms a recess 13 at its bottom and a protrusion 15 at its top (FIGS. 2 and 7). The upper wall 19 is configured to at least partially cover the condyle while leaving its interior medial portion substantially open. To this end, the outer shell 18 is open at the bottom and along the lateral-medial axis X in the region facing the outer lateral wall 20 and the end of the upper wall 19.

[0041] The outer lateral wall 20 has its main development along the ramus 114 and is substantially parallel or sub-parallel to the median plane of the body. Optionally, the external lateral wall 20 may be provided with one or more through holes 21 for the insertion of attachment elements, such as screws 22 (see, for example, Figs. 2 and 5-6). The screws 22 make it possible to obtain a primary fixation of the first prosthetic part 11 to the patient's mandibular condyle, at least during the period of osseointegration. The dimensions and length of the screws 22 vary according to the configuration and dimensions of the condyle.

[0042] In this embodiment described herein, and with particular reference to Figures 2 and 7, the outer shell 18 also comprises a pair of opposing walls, anterior wall 23 and posterior wall 24, which are adapted to at least partially encase the condyle anteriorly and posteriorly to ensure greater fixation. The anterior wall 23 and posterior wall 24 are connected at their upper portions to the upper wall 19, on one and the other side of the upper wall 19, respectively, and laterally to the outer lateral wall 20.

[0043] Although the top wall 19, the outer side walls 20, and the front and rear walls 23, 24 have been described as separate and distinct elements, it will be appreciated that they may be integrated and one may be an extension of the other according to their geometric shapes and mutual arrangement as described.

[0044] In some embodiments described herein, the anchor element 16 is configured as a plate 25, which is attached with its upper part to the upper wall 19, on the side of the recess 13 and laterally to the external side wall 20. However, it is not excluded that the plate 25 can only be attached to the upper part 19. The plate 25 can also be formed as a wall, a bulkhead, a suitably shaped ridge protruding from the upper wall 19.

[0045] In particular, the plate 25 projects in a direction substantially perpendicular to the upper wall 19 (FIGS. 2 and 7). The plate 25 divides the coupling seat 14 substantially into two parts, each of which can be placed on a part of the condyle 112 that lies in the face of the anchor seat 113 (FIG. 11).

[0046] The plate 25 has a longitudinal extension or length L in the direction of the external-internal axis X that is approximately equal to the extension of the upper wall 19 in the direction of the external-internal axis X (FIG. 2). However, it is not excluded that the plate 25 has a shorter length L. Obviously, a larger length L provides a larger effective surface area in contact with the bone of the condyle for better integration and fixation.

[0047] The plate 25 has a height H (FIG. 4) proportional to the depth of the anchor seat 113 (FIG. 11) provided on the condyle 112. For example, the height H can have a minimum value of 4 mm, but can also be greater.

[0048] The plate 25 has a thickness W1 (FIG. 7) that is significantly smaller than the length L. For example, the thickness W1 can vary between about 1 mm and about 4 mm. Preferably, the thickness W1 is comprised between about 2 mm and about 3 mm.

[0049] Advantageously, the plate 25 is configured to promote primary fixation of the prosthesis, regeneration of cancellous bone, and osseointegration with the cortical bone of the condyle 112 . In particular, the plate 25 can have a substantially rectangular shape and can be provided with major and minor grooves to promote primary fixation of the prosthesis, regeneration of cancellous bone, and osseointegration with the cortical bone of the condyle 112.

[0050] In one embodiment (FIGS. 2 and 4), the plate 25 is provided with a number of teeth 26 suitably spaced to form large grooves as described above to promote bone growth therein during use in order to ensure greater stability of the first prosthetic element 11. For example, the plate 25 and the teeth 26 form a comb-like configuration.

[0051] The plate 25 may be provided with a chamfer 29 that may facilitate the insertion of the first prosthetic element 11 in the lateral-medial direction in the anchor seat 113 on the condyle 112. In this case (FIG. 4), the shape of the plate 25 may be trapezoidal, and the inclined surface forming the chamfer 29 may have more than one inclination or may be formed by a curved surface.

[0052] In some embodiments, the first prosthetic element 11 is made of a biocompatible material (e.g. titanium or its alloys, or other possible known or unknown biocompatible materials). Advantageously, the connection surface of this first prosthetic element 11 can be treated to be as smooth as possible (e.g. mirror-like) in order to reduce friction during articulation to a minimum.

[0053] In particular, the plate 25 can be made of titanium, the surface of which can preferably be treated to increase the contact surface with the bone and promote osseointegration with the bone. For example, the surface of the plate 25 can be treated by sandblasting with hydroxyapatite and acid passivation (RBM). In a possible embodiment, the plate 25 can alternatively have an at least partially porous or lattice-like structure (e.g. reproducing the trabecular structure of the bone, which may be related to some of the dense material) for the purpose of osseointegration.

[0054] Optimal osseointegration is also promoted by surgical site preparation with piezosurgery, where bone tissue is preserved and much less damaged than with conventional cutters for bone orthodontic site preparation.

[0055] In some embodiments, the first prosthetic element 11 can be produced by a Selective Laser Melting (SLM) process or a Direct Metal Laser Sintering (DMSL) process, or by an Electron Beam Melting (EBM) technique, or generally by a suitable "additive manufacturing" or 3D printing technique based on the specific anatomical needs of the patient. Such techniques are advantageous, for example, when the first prosthetic element 11, and in particular the plate 25, at least partially has, for example, a porous or lattice-like structure, for example columns (which may be associated with parts of a dense material).

[0056] In the embodiment shown in Figures 1 and 3, the second prosthetic member 12 may be configured as a socket prosthesis that is configured to cover the mandibular socket of the patient. The second prosthetic element 12 comprises a connection portion 30 capable of cooperating with the convex portion 15 of the first prosthetic element 11 in use, and a zygomatic projection portion 31 capable of covering the patient's zygomatic arch in use.

[0057] The connecting portion 30 has a convex connecting surface 32 shaped to engage the protrusion 15 . The upper portion of connecting portion 30 (which in use rests against the patient's mandibular glenoid) has a shape which traces the pre-existing (or surgically shaped) bone surface of the glenoid.

[0058] The second prosthetic element 12 can be fixed to the temporal bone by means of screws 34. For this purpose, both the connection part (its outermost part) and the zygomatic process part 31 can be provided with through holes 33 for the screws 34. In the example described here, the zygomatic process part 31 is fixed with three screws 34.

[0059] In some embodiments, the second prosthetic member 12 is made of a biocompatible material (eg, ultra-high molecular weight polyethylene (UHMWPE), or other possible known or unknown biocompatible materials).

[0060] 9 to 11, a guide device (in this particular case a surgical template) 35 comprises a central body 36 capable of wrapping at least the upper lateral part of the ramus and a guide wall 37 attached at its upper part to the central body 36 and having the profile of the osteotomy to be performed on the patient's condyle 112. In particular, the central body 36 may be suitable to partially wrap the anterior and posterior surfaces of the condyle 112 for better positioning.

[0061] The surgical template 35 has an open-top central vertical slot 38. The central vertical slot 38 divides the guide wall 37 into a first guide branch 37a and a second guide branch 37b. In the examples described herein, the guide wall 37 has a substantially curved profile, however, it is not excluded that the guide wall 37 may have a square profile or any other profile suitable for making the bone correction procedure as minimally invasive as possible.

[0062] The vertical groove 38 opens in an orientation parallel to the lateral-medial axis X to prepare the anchor seat 113 in the patient's condyle 112 to enable the surgeon to perform a vertical osteotomy.

[0063] The guide groove 38 may also extend partially into the central body 36 . The groove 38 is open at the top and has an end or bottom 39 which can function as an abutment for a scalpel during preparation of the anchor seat 113 (FIG. 11).

[0064] The groove 38 has a depth D approximately equal to the height H of the plate 25 of the first prosthetic component 11 and a width W2 equal to or less than the thickness W1 of the plate 25 (FIG. 11). Furthermore, the groove 38 may be slightly tapered from its upper opening to its distal end 39.

[0065] The surgical template 35 comprises one or more prepared holes 40 prepared through the central body 36. The prepared holes 40 allow corresponding holes to be prepared in the patient's condyle 112 for placing screws that serve to attach the first prosthetic element 11 following fixation of the surgical template 35. In a possible implementation, the prosthetic element of the condyle (i.e. the condyle 112) can be modeled and shaped on its outer lateral side to accommodate more attachment screws. For this purpose, the use of a dedicated template can also be provided.

[0066] In operation, after identification of the portion of the condyle 112 to be removed, a surgical template 35 with a profile appropriately shaped according to the anatomical needs of the patient is placed on the condylar ramus 114 and attached by screws (not shown) (FIG. 10). Subsequently, a first osteotomy is performed according to the profile of the guide wall 37, then a second vertical osteotomy is performed along the groove 38 to create an anchor seat 113 (FIG. 11) for receiving the plate 25. Preferably, the osteotomy is performed with a scalpel with a piezo handle to ensure that the accuracy of the cut is maximized.

[0067] It will be apparent that modifications and / or additions may be made to the temporomandibular joint prosthesis and corresponding prosthetic assembly described above without departing from the field and scope of the invention as defined by the claims.

[0068] Furthermore, although the invention has been described with respect to some specific examples, it is clear to those skilled in the art that many other equivalent forms of prosthetic devices for temporomandibular joints and corresponding prosthetic assemblies are obtainable which have the features set out in the claims and which therefore fall within the scope of protection defined by the claims.

[0069] In the following claims, the references within parentheses are for ease of reading only and are not to be considered as limiting factors with respect to the scope of protection claimed by a particular claim.

Claims

1. A prosthesis (10) for a temporomandibular joint, comprising a first prosthetic part (11) connectable to a mandibular condyle (112) of a patient and a corresponding second prosthetic part (12) connectable to a respective mandibular condyle of the patient, said first prosthetic part (11) being adapted to cooperate with said second prosthetic part (12) to form said temporomandibular joint, said first prosthetic part (11) comprising a recess (13) forming a coupling seat (14) having a shape that engages with the shape of said mandibular condyle, said first prosthetic part (11) comprising:

1. A prosthesis comprising one or more anchor elements (16) protruding from and attached at least to said recess (13), said anchor elements (16) being housed within said recess (13), said anchor elements (16) having a main extension along a lateral-medial axis (X) and configured to be inserted into an engaging anchor seat (113) present on said mandibular condyle (112), said coupling seat (14) being at least partially open along said lateral-medial axis (X).

2. 2. The prosthesis of claim 1, wherein the first prosthesis part (11) further comprises an external lateral part (17) configured to be coupled laterally to the condyle (112).

3. 3. The prosthesis according to claim 1 or 2, wherein the first prosthesis element (11) comprises an outer shell (18) having an upper wall (19) and an outer side wall (20) arranged at an angle to the upper wall (19), the outer shell (18) being open at the bottom and also open along the outer-internal axis (X) in the region facing the outer side wall (20) and the end of the upper wall (19).

4. 4. The prosthesis according to claim 3, wherein the anchor element (16) is configured as a plate (25), the plate being fixed with its upper part against the upper wall (19) on the side of the recess (13), the plate (25) protruding laterally against the outer lateral wall (20) and in a direction substantially perpendicular to the upper wall (19).

5. A prosthetic device as described in claim 4, wherein the length of the plate (25) in the direction of the lateral-medial axis (X) is approximately equal to the length of the upper wall (19) in the direction of the lateral-medial axis (X).

6. 6. The prosthesis of claim 5, wherein the plate (25) is configured to promote primary fixation of the prosthesis, regeneration of cancellous bone and osseointegration with the cortical bone of the condyle (112).

7. 7. The prosthesis of claim 6, wherein the plate (25) is provided with major and minor grooves for promoting cancellous bone regeneration and osseointegration with the cortical bone of the condyle (112).

8. 8. The prosthesis of claim 7, wherein said plate (25) is provided with a plurality of teeth (26) suitably spaced to define said grooves.

9. 9. A guide device for preparing an anchor seat (113) for a prosthesis according to any one of claims 1 to 8, comprising a central body (36) which can be positioned at least against an upper lateral part of the ramus, and a guide wall (37) connected to said central body (36) at an upper part and having a profile of a bone orthopedic procedure to be performed on said condyle (112), said guide device having a groove (38) extending vertically from said guide wall (37) towards said central body (36), said groove (38) being open at the upper part and opening in a direction parallel to an lateral-medial axis (X), said groove (38) having a depth (D) approximately the same as a height (H) of a plate (25) which serves as an anchor element (16) of the prosthesis.

10. 10. The guide device according to claim 9, wherein the groove (38) divides the guide wall (37) into a first guide branch (37a) and a second guide branch (37b).

11. A guide device according to claim 9 or 10, wherein the groove (38) has an end or bottom portion (39) capable of acting as an abutment for a scalpel.

12. A prosthetic assembly for a temporomandibular joint, comprising a prosthesis (10) according to any one of claims 1 to 8 and a guide device (35) according to any one of claims 9 to 11.

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