GLENOID COMPONENT FOR SHOULDER PROSTHESIS AND RELATED SHOULDER PROSTHESIS

Abstract

The present invention relates to a glenoid component (100, 600, 800, 1000, 1200) for shoulder prosthesis, comprising: a glenoid coupling surface (101, 1001), adapted to be fixed to a bone and comprising a first convex portion (102) having a first outer edge (103, 1003) which defines a development plane (104, 1004); a prosthetic coupling surface (105, 1005), opposite the glenoid coupling surface (101, 1001) and adapted to house a second prosthetic component of the shoulder prosthesis, the prosthetic coupling surface (105, 1005) comprising a second portion (106) having a second outer edge (107, 1007) which defines a reference plane (108, 1008); wherein the glenoid component (100, 1000) provides a predetermined offset (109, 809, 1009) between the development plane (104, 1004) and the reference plane (108, 1008), so as to define an increased thickness of the glenoid component (100, 1000) adapted to compensate for a bone deficit. The present invention also relates to a shoulder prosthesis.

Claims

1-12. (canceled)

13. A glenoid component for shoulder prosthesis, comprising: a glenoid coupling surface, for fixing to a bone and comprising a first convex portion having a first outer edge which defines a development plane; a prosthetic coupling surface, opposite said glenoid coupling surface for housing a second prosthetic component of said shoulder prosthesis, said prosthetic coupling surface comprising a second portion having a second outer edge which defines a reference plane; a substantially truncated cone-shaped glenoid coupling element, projecting from said glenoid coupling surface and for coupling to a bone pin of said shoulder prosthesis, said glenoid coupling element developing along an axis which is substantially perpendicular to said reference plane; wherein said glenoid component provides a predetermined offset between said development plane and said reference plane, wherein said predetermined offset is configured to vary a longitudinal distance along the perimeters of said first outer edge and of said second outer edge, defining an angle between said development plane and said reference plane, said predetermined offset defining an increased thickness of said glenoid component for compensating a bone deficit, wherein said first outer edge of said glenoid coupling surface is substantially circular, and wherein said second outer edge of said prosthetic coupling surface is substantially circular, so as to allow an orientation of the glenoid component in a continuous way, covering all types of bone defects over 360°.

14. The glenoid component according to claim 13, wherein said angle is comprised between 2° and 30°.

15. The glenoid component according to claim 13, wherein said angle is comprised between 5° and 25°.

16. The glenoid component according to claim 13, wherein said angle is available with increases by 5°.

17. The glenoid component according to claim 13, wherein said first convex portion provides a substantially constant curvature radius.

18. The glenoid component according to claim 17, wherein said second portion is concave.

19. The glenoid component according to claim 17, wherein said substantially constant curvature radius is comprised between 25 and 35 mm.

20. The glenoid component according to claim 17, wherein said substantially constant curvature radius is comprised between 27 and 30 mm.

21. The glenoid component according to claim 13, further comprising at least two holes for receiving fixing screws of said glenoid component of said shoulder prosthesis.

22. The glenoid component according to claim 21, wherein said at least two holes for housing respective angular locking screws.

23. The glenoid component according to claim 22, wherein said predetermined offset comprises a first offset at said at least two holes and a second offset at a glenoid coupling element.

24. The glenoid component according to claim 23, wherein said first offset comprises a first threaded portion for housing a peripherally threaded closure element.

25. The glenoid component according to claim 24, wherein said second offset comprises a second threaded portion for housing a head of a respective angular locking screw.

26. The glenoid component according to claim 13, wherein said glenoid coupling surface comprises a trabecular porous structure for increasing stability and osteo-integration of said glenoid component.

27. The glenoid component according to claim 13, further comprising retentive elements protruding from said prosthetic coupling surface

28. The glenoid component according to claim 27, wherein said retentive elements are configured to house and retain an anatomic liner.

29. The glenoid component according to claim 13, wherein a set of said glenoid components provides respective different predetermined offsets so as to define a plurality of different standard increased thicknesses for compensating different bone deficits.

30. A set of glenoid components according to claim 13, each glenoid component of said set providing a respective predetermined offset, so as to define a plurality of standard increased thicknesses for compensating different bone deficits.

31. A shoulder prosthesis comprising: a glenoid component according to claim 13; at least one second prosthetic component connected to said glenoid component.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The invention is illustrated with reference to the following figures, given by way of non-limiting example, in which:

[0053] FIGS. 1A and 1B illustrate front and rear perspective views of an embodiment of a glenoid component according to the present invention;

[0054] FIG. 2 illustrates a possible coupling of the glenoid component of FIG. 1 with a bone pin;

[0055] FIGS. 3A and 3B illustrate an exemplifying coupling of the glenoid component of FIGS. 1A and 1B on a scapula;

[0056] FIG. 4 illustrates a side view of the glenoid component of FIGS. 1A and 1B;

[0057] FIG. 5 illustrates possible variants of the glenoid component of FIGS. 1A and 1B;

[0058] FIG. 6 illustrates a further variant of a glenoid component of FIGS. 1A and 1B;

[0059] FIG. 7 illustrates the glenoid component of FIGS. 1A and 1B coupled with fixing screws;

[0060] FIG. 8 illustrates a second embodiment of a glenoid component according to the present invention;

[0061] FIG. 9 illustrates a side view of the glenoid component of FIG. 8;

[0062] FIG. 10 illustrates an exploded view of an exemplifying shape of the glenoid part of a reverse shoulder prosthesis comprising the glenoid component of FIGS. 1A and 1B;

[0063] FIGS. 11A and 11B illustrate front and rear perspective views of a further embodiment of a glenoid component according to the present invention;

[0064] FIGS. 12A and 12B illustrate front and rear perspective views of a variant of the glenoid component of FIGS. 11A and 11B;

[0065] FIG. 13 illustrates possible variants of the glenoid component of FIGS. 11A and 11B;

[0066] FIG. 14 illustrates a possible coupling with an anatomic liner of the glenoid component of FIGS. 11A and 11B;

[0067] FIG. 15 illustrates an exploded view of a further exemplifying shape of the glenoid part of a reverse shoulder prosthesis comprising the glenoid component of FIGS. 11A and 11B;

[0068] FIGS. 16A and 16B illustrate a further exemplifying coupling of the glenoid component of FIGS. 11A and 11B on a scapula;

[0069] FIG. 17 illustrates a perspective view of a further embodiment of a glenoid component according to the present invention;

[0070] FIG. 18 illustrates a further perspective view of the variant of FIG. 17 coupled with a fixing screw;

[0071] FIGS. 19A and 19B illustrate a perspective view and a sectional view of the variant of FIG. 17 coupled with a fixing screw.

[0072] In the different figures, analogous elements will be identified by analogous reference numbers.

DETAILED DESCRIPTION

[0073] With reference to the enclosed Figures, reference number 100 globally indicates an embodiment of a glenoid component for a shoulder prosthesis made according to the present invention.

[0074] FIG. 1 represents an embodiment of the glenoid component 100 comprising a glenoid coupling surface 101, adapted to be fixed to a bone. The glenoid coupling surface 101 comprises a first convex portion 102 having a first outer edge 103 which defines a development plane 104. The glenoid component 100 further comprises a prosthetic coupling surface 105, opposite the glenoid coupling surface 101 and adapted to house a second prosthetic component of the shoulder prosthesis. The second prosthetic component is preferably a humeral component of the shoulder prosthesis.

[0075] The prosthetic coupling surface 105 comprises a second portion 106 having a second outer edge 107 which defines a reference plane 108. The second portion 106 is preferably concave.

[0076] The glenoid component provides a predetermined offset 109 between the development plane 104 and the reference plane 108.

[0077] Furthermore, the glenoid component 100 comprises a substantially truncated cone-shaped glenoid coupling element 110, protruding from the glenoid coupling surface 101. The glenoid coupling element 110 may be made integral or removable with respect to the body of the glenoid component 100.

[0078] As visible in FIG. 2 the glenoid coupling element 110 is adapted to be coupled to a bone pin 111. Since this coupling is of the modular type, preferably a conical coupling of the morse cone type, there is the possibility of using bone pins 111 of various length, based on the bone quality and on the stability desired by the surgeon during the operation. The freedom of use with the same glenoid component 100 is consequently maximum for a surgeon. The glenoid coupling element 110 develops along an axis that is substantially perpendicular to the reference plane 108.

[0079] In the present embodiment the glenoid component 100 comprises four through-holes 112, adapted to house fixing screws of the glenoid component 100. A recess 113 with a preferably substantially parallelepiped section at the glenoid coupling surface 101 corresponds to each hole 112. Furthermore, preferably around the glenoid coupling element 110 a circular recess 114 in connection with the recesses 113 is provided.

[0080] In FIGS. 3A and 3B a possible exemplifying application of the glenoid component 100 on a scapula is visible. In the present exemplifying and non-limiting embodiment both the first outer edge 103 of the glenoid coupling surface 101 and the second outer edge 107 of the prosthetic coupling surface 105 are substantially circular. The present configuration allows an orientation of the glenoid component 100 in a continuous way, which covers all types of defects over 360°. Nothing prevents the use of different conformations. For instance, it is possible to provide a first outer edge 103 of the glenoid-shaped glenoid coupling surface 101, which represents the optimal condition for a prosthesis of the anatomic type, wherein the humeral head articulates on the glenoid surface.

[0081] However, this exemplifying solution is only suitable for reverse prosthesis. Reverse prosthesis means a prosthesis that does not rely on the action of the rotator cuff muscles but relies on the deltoid muscle. In other words, it is a prosthesis with the head on the scapular glenoid that articulates on a spherical liner positioned on the humeral part, using the lever arm of the deltoid. This type of prostheses are used in patients with irreparable injuries of the rotator cuff with loss of function and strength of the shoulder, precisely, in which it is not possible to adopt the rotator cuff muscles to make the shoulder prosthesis work.

[0082] FIG. 4 represents a side view of the glenoid component 100 in which the first convex portion 102 is particularly visible, said first portion 102 preferably providing a curvature radius R that is substantially constant, preferably comprised between 25 and 35 mm, more preferably between 27 and 30 mm. Said conformation allows replicating the bone curvature radius of the original glenoid in the best possible way and obtaining a correct seat for the glenoid component 100 using the same tool for all of the configurations.

[0083] Furthermore, the embodiment represented in FIG. 4 has a predetermined offset 109 configured to vary a longitudinal distance along the perimeters of the first outer edge 103 and of the second outer edge 107, thus defining an angle α between the development plane 104 and the reference plane 108.

[0084] FIG. 5 represents different variants of said embodiment. Considering that in all cases it is necessary to establish the right correction, the glenoid component 100 according to the different variants provides different inclinations of the development plane 104 of the first convex portion 102 and thus from different angles α, to be considered based on the severity of the defect. It should be borne in mind that even an excessive correction with respect to the neutral position (in which a patient is in an upright position with the limb under examination adducted along the side and with the palm of his hand facing the lateral side of the corresponding lower limb) may also cause problems in the medium-long term to the patient.

[0085] As stated, the first portion 102 of the glenoid coupling surface 101 is convex with a curvature radius R that is constant for all of the configurations to use the same tool, which in the present case is represented by a cutter with the same curvature radius. It is therefore sufficient to orient the cutter in the correct way based on the defect. In particular, FIG. 5 represents variants with angles 0° to 25° with increases by 5°. Clearly, said representation is only illustrative and non-limiting of the scope of protection defined by the appended claims. This example is selected since the angles represented are the most frequent and an increase by 5° between one variant and the other is considered the minimum appreciable. As stated, however, it is possible to make the glenoid component 100 with all possible intermediate angles, based on the surgeon's specific needs, such as 17.5° or 12° angles. For glenoid components 100 with greater angulations longer bone pins 111 are used, as the added material part covers a part of the exposed surface of the pin.

[0086] Preferably, the glenoid component 100 is not made with angles greater than 30°, preferably not greater than 25°, to avoid mechanical strength complications of the glenoid component 100 increasing the lever arm between point of application of force and bone. Generally, to correct very severe deficits, such as with an angle of 35°, it is preferable to use a glenoid component 100 combined with a preliminary milling operation on an inclined axis, with respect to the eroded surface. However, nothing prevents the provision of a more resistant glenoid component 100 and adopting higher angles of the development plane 104.

[0087] Moreover, the increased thickness of the glenoid components shown in FIG. 5 are defined by a maximum offset between the glenoid coupling surface and the prosthetic coupling surface that ranges from about: 10% for 0°, 20% for 5°, 25% for 10°, 33% for 25°, 43% for 20°, 50% for 25° with respect to the respective diameter of the glenoid component.

[0088] The position of the convexity curvature center of the glenoid component 100 is selected, in the various configurations, in order to ensure the desired angle α and at the same time to ensure a minimum thickness of the glenoid component 100, still in order to avoid any mechanical seal problems.

[0089] In the present case with a first circular outer edge 103 and second circular outer edge 107 it is sufficient to position the thickest part of the glenoid component 100 along the direction of the bone deficit.

[0090] FIG. 6 further represents a variant 600 of the glenoid component 100 in which a porous/trabecular structure 601 is provided on the glenoid coupling surface 101, in order to increase the stability and osteo-integration of the glenoid component 100 at the bone. A trabecular structure is a structure that incorporates that characteristic of bone tissue, with lamellae arranged forming intercommunicating cavities.

[0091] As stated and as most visible in FIG. 7, the glenoid component 100, in the present embodiment, has four holes 112 adapted to house fixing screws 715 to the bone surface. In said embodiment the four holes 112 allow choosing the position and the optimal number of fixing screws 715 for the fixing even in the case of glenoid component 100 oriented along hybrid defects, for instance an inferior-posterior deficit inclined by 45°.

[0092] FIG. 8 represents a different embodiment 800 in different variants. In said embodiment the predetermined offset 809 is configured to maintain a longitudinal distance substantially constant along the perimeters of the first outer edge 803 and of the second outer edge 807, wherein said development plane 104 and said reference plane 108 are substantially parallel to each other. Said embodiment is particularly suitable in the case of central erosions of the glenoid. Indeed, under this condition, after an on-axis milling operation that eliminates the deficit part, a glenoid component 800 is required, which is increased not angularly but in terms of flat thickness, which brings the milled articular surface back to the same original height. The variants represented in FIG. 8 differ from each other in the different thicknesses S.

[0093] The glenoid coupling surface 801, as visible in FIG. 9, has in this case as well a first convex portion 802, with a constant curvature radius R. The convexity curvature center is, in this case, always in axis with the glenoid component 800. Therefore, in the preparatory phase, the seat for the glenoid component 800 is made with a cutter with the same radius R, seat which is positioned coaxially and actuated until the central defect is eliminated. Additionally to its use to compensate for central bone deficits, the present embodiment is suitable for correctly tensioning the soft tissues. Preferably, to avoid mechanical seal drawbacks, the present embodiment is made with thicknesses that are not too high.

[0094] Moreover, the increased thickness of the glenoid components shown in FIG. 8 are defined by a maximum offset provided by respective predetermined offsets 809 between the development plane defined by the first outer edge 803 and the reference plane defined by the second outer edge, that ranges from about: 9%, 18%, 25% with respect to the respective diameter of the glenoid component.

[0095] In that respect, the ‘normal’ thickness of a glenoid component is defined by an offset of about 9% of the diameter of the glenoid component, while the increased thickness of the glenoid components is defined by larger offsets, preferably larger than 15%, more preferably larger than 25%, as also exemplified with reference to FIG. 5 above.

[0096] Preferably the longitudinal distance is comprised between 2 and 10 mm, more preferably comprised between 4 and 6 mm.

[0097] However, nothing prevents the use of more resistant components with different thicknesses, included in the scope of protection defined by the appended claims.

[0098] FIG. 10 represents an exploded view of an exemplifying shape of the glenoid part of a reverse shoulder prosthesis comprising a glenoid component 100 comprising a glenoid coupling element 110 and grafted with fixing screws 715, a bone pin 111 and a prosthetic hemisphere 116.

[0099] In the event that the surgeon deems it necessary to use an anatomical prosthesis and not a reverse prosthesis, for example in the case of a young patient with an intact rotator cuff, a further embodiment of glenoid component 1000 is provided, which is represented in two different variants in FIGS. 11A and 11B, and 12A and 12B.

[0100] In particular, FIGS. 11A and 11B represent a configuration for bone deficits in the inferior-superior direction (I-S), whereas FIGS. 12A and 12B represent a configuration for anterior-posterior bone deficits (A-P).

[0101] As it may be seen, this embodiment in both the represented variants provides both the first outer edge 1003 of the glenoid coupling surface 1001 and the second outer edge 1007 of the substantially oval-shaped prosthetic coupling surface 1005. Two variants are required since it is not possible to rotate the glenoid component 1000 due to asymmetry issues analogously to the embodiment with circular outer edges 103 and 107.

[0102] As this is an anatomic prosthesis, the glenoid component 1000 must be positioned vertically on the glenoid to anatomically reproduce the surface. In the case of hybrid defects, for instance upper-posterior with a 45° inclination, it is therefore necessary to select one of the two conditions, either posterior or superior, and prepare the seat with a milling operation until the defect is eliminated. Alternatively, however, it is possible to develop a dedicated glenoid component 1000 for a specific bone deficit.

[0103] Even in this embodiment the glenoid component 1000 comprises a substantially truncated cone-shaped glenoid coupling element 1010, protruding from the glenoid coupling surface 1001 and being adapted to be coupled to a bone pin 1111, and which develops along an axis that is substantially perpendicular to a un reference plane 1008. Even in this embodiment it is possible to modularly couple a bone pin 1111 of various lengths. It is possible to adopt the same glenoid component both in a configuration of the reverse type, as well as in the case of an anatomical prosthesis, since the geometry of the glenoid coupling element 1000 is similar. This is particularly useful in the event that a conversion is required, namely a transition to an implant of the reverse type after a first implant of the anatomical type.

[0104] The glenoid component 1000, as visible in FIG. 13, provides same features as the previous embodiments. In particular, variants with a predetermined offset 1009 configured to vary a longitudinal distance along the perimeters of a first outer edge 1003 and a second outer edge 1007, defining an angle α between a development plane 1004 and a reference plane 1008, are visible. Even in this case an angle α range comprised between 5° and 25° is preferable, but nothing prevents the adoption of different angles.

[0105] Variants with a predetermined offset 1009 configured to maintain the longitudinal distance along the perimeters of the first outer edge 1003 and the second outer edge 1007 substantially constant, in cases of central erosion, are further visible. Even in this case a range of longitudinal distance comprised between 4 mm and 6 mm is preferable, but nothing prevents from providing different longitudinal distances.

[0106] In all cases a constant curvature radius R is provided, with the same characteristics regarding the convexity curvature center described for the corresponding embodiments described above.

[0107] Retentive elements 1110 protruding from the prosthetic coupling surface 1001 are preferably further provided.

[0108] Said retentive elements 1110 are preferably adapted, as visible in FIG. 14, to house and retain an anatomic liner 1113, namely a coating will replicate the surface on which the humeral head will articulate. Said element protects and reduces the impact and allows the coupling between humeral head and glenoid. Preferably the anatomic liner 1111 is made of polyethylene. In FIG. 14 it is further visible that the present embodiment, given the particular conformation, allows the use of two fixing screws 1115 and thus provides only two holes 1112.

[0109] FIG. 15 represents an exploded view of an exemplifying shape of the glenoid part of a reverse shoulder prosthesis comprising a glenoid component 1000 comprising a glenoid coupling element 1010 and grafted with fixing screws 1115, a bone pin 1111 and a prosthetic hemisphere 1116.

[0110] In FIGS. 16A and 16B a possible exemplifying application of the glenoid component 1000 on a scapula is visible. It is possible to make the glenoid component 1000 of various length and width dimensions in order to replicate the correct geometry of the glenoid for the anatomical implant, and to consequently adopt anatomical liners of different sizes.

[0111] In case the surgeon provides for the use of an angular locking screw, an alternative embodiment 1200 is further provided as represented in FIGS. 17, 18, 19A and 19B, in which the holes 112 are suitable for housing respective angular locking screws 1201.

[0112] According to said embodiment, the predetermined offset 109 at the prosthetic coupling surface 105 of the glenoid component 1200 comprises a first offset 109A at the holes 112 and a second offset 109B, at the glenoid coupling element 110. The first offset 109A is preferably comprised between 1 mm and 7 mm, even more preferably between 2 mm and 4 mm. In this embodiment, it is observed that the first offset 109A represents an additional thickness, whereas the second offset 109B substantially corresponds to the entire thickness 109 of the other embodiments previously described. The first offset 109A thus acts as an additional thickness and allows introducing a locking element for the angular locking screws 1201.

[0113] The portion of the glenoid component 1200 comprising the glenoid coupling element 110 remains unchanged by not introducing any lateralization, whereas the glenoid component 100 provides an offset at the holes 112 that is configured to provide a space for poly-axial locking of the screws 1201.

[0114] As better visible in the sectional view of FIG. 19B, the first offset 109A comprises in this embodiment a first threaded portion 1202, adapted to house a closure element 1203 that is peripherally threaded. The peripherally threaded closure element 1203 is similar to a threaded covering and locking cap for the screw 1201.

[0115] The second offset 109B comprises a second threaded portion 1204 adapted to receive a head 1205 of one of the angular locking screws 1201. In the embodiment illustrated, the figures in particular represent a hemispherical head of the screw 1201 with hexagonal recess in which a related peripherally threaded closure element 1203 is inserted, said embodiment being, as stated, exemplifying and non-limiting.

[0116] Specifically, the fixing screw 1201 is oriented and screwed in the same way as the previously described embodiments, while the closure element 1203 will allow its angular locking once introduced. The closure element 1203 is thus screwed until it abuts onto the head of the angle locking screw 1201, compressing and locking it polyaxially.

[0117] Clearly, the present solution may be applied at all of the holes 112 or at a subset thereof.

[0118] In a variant, nothing prevents from providing a second non-threaded offset 109B and only providing a first threaded offset 109A, in particular in the case of not particularly accentuated angles desired for the screw 1201, angles for which the same screw 1201 is mostly protruding.

[0119] It is further possible to provide a further variant with a different locking solution, for example by adopting fixing screws with an oversized head comprising an expandable elastic element. In this case, the poly-axial locking of the screw 1201 could be obtained by expanding the elastic element within the first offset 109A, without the need for the latter to provide threaded portions.

[0120] The present invention further provides at least one shoulder prosthesis comprising a glenoid component according to one of the embodiments and variants of the invention and at least one related prosthetic component associated with the glenoid component, such as for instance the above-described anatomic liner 1113.

[0121] Advantageously, the present invention allows for a range of possibilities in correcting bone deficits with standard and tested elements as suitable for the specific clinical conditions of a patient.

[0122] Furthermore, the present invention combines peculiarities under different conditions, with different characteristics for specific bone deficits, and a universality of use in particular by providing a surface adapted to couple on the convex glenoid with constant radius, so as to allow the adoption of a single tool by of a surgeon in the preparatory phase.

[0123] Advantageously, the present invention is suitable for different conditions of bone deficits, whether due to angular erosion or due to central erosion.

[0124] Advantageously, the present invention allows optimizing time and precision of surgical operations peculiar to the shoulder.

[0125] Still advantageously, the present invention provides a relatively simple and intuitive application for a surgeon.

[0126] Still advantageously, the present invention provides for coupling with existing devices, such as bone pins, also allowing a coupling with several bone pins of various lengths with a single glenoid component.

[0127] Finally, advantageously the present invention does not have particularly complex structural characteristics, making it suitable for large-scale production, with obvious impact also from an economic point of view.

[0128] It should also be noted that the different embodiments each further present specific and peculiar advantages as described.

[0129] It is evident that, where there are no technical incompatibilities evident to the skilled person, the configurations of specific elements described with reference to certain embodiments can be used in other embodiments described herein.

[0130] For instance, it is possible to use a trabecular-porous structure 601 even in the embodiment with an oval peripheral structure.

[0131] The embodiments described herein are therefore to be understood as illustrative and non-limiting examples of the invention.