humeral anchoring element for shoulder prosthesis

Abstract

The invention relates to a humeral anchoring element (2) for a humeral joint part (4, 4') of a shoulder prosthesis, the humeral anchoring element (2) being characterized in that it comprises: - a main body (8) intended to be inserted inside a humerus (16) from a resected metaphyseal surface (10), and - a proximal collar (12) forming a proximal end of the humeral anchoring element (2) and placed at one end of the main body (8), a proximal face (14) of the proximal collar (12) extending into the humerus (16) and below the resected metaphyseal surface (10). Figure for abstract: figure 1

Description

Title of the invention: humeral anchoring element for shoulder prosthesis

[0001] The present invention relates to a humeral anchoring element allowing the anchoring to a humerus of a humeral articular part of a shoulder prosthesis.

[0002] It is well known to anchor a humeral joint part by means of a tapered medullary rod that this part comprises. The medullary rod has a flared proximal part, intended to be placed at the level of the bone metaphysis, and a tapered distal part intended to be inserted into the medullary canal up to the level of the diaphysis. Such a joint part with a medullary rod can however be difficult to implant when the bone is not of good quality, particularly in the case of osteoporosis in an elderly patient. The same is true in the case of revision of a previously implanted prosthesis, this previous implantation having already led to more or less significant bone removal. In either case, fixation of the joint part relative to the bone may not be perfect and may not perfectly withstand the repeated stresses undergone by the prosthesis over time.

[0003] In another case, and for a patient with healthy bone (for example, a younger patient) but a joint worn by numerous stresses (for example, due to work or sports) and / or for whom an intervention at the level of the rotator cuff muscles is not or no longer possible, the improvement in the hold of the prostheses over time makes it possible to carry out a prosthesis placement using an anchoring element without a medullary rod. This is due to the fact that it is possible to stabilize the prosthesis without having to look for an anchoring point low enough in the diaphyseal part of the humerus because the epiphysis and the metaphysis are of good quality. The anchoring element then extends into the metaphyseal part of the bone, after resection of the humeral head.

[0004] In both cases, the stacking of the elements forming the humeral joint part can lead to a displacement of the center of rotation of the humerus joint towards the glenoid. This is not optimal because, without a prosthesis, the center of rotation of the anatomical joint is located at the level of the humerus and not the glenoid. The installation of a prosthesis can therefore lead to a displacement of the center of rotation of the joint to create a situation which does not reproduce the anatomical joint situation.

[0005] The present invention aims in particular to remedy this drawback by providing a humeral anchoring element making it possible to maintain a positioning of the center of rotation of the joint as close as possible to an anatomical reality. of the joint.

[0006] To this end, the invention relates to a humeral anchoring element for a humeral joint part of a shoulder prosthesis, the humeral anchoring element comprising: - a main body intended to be inserted inside a humerus from a resected metaphyseal surface, and - a proximal collar forming a proximal end of the humeral anchoring element and placed at one end of the main body, a proximal face of the proximal collar extending into the humerus and below the resected metaphyseal surface.

[0007] Thus, the anchoring element is placed entirely inside the humerus and below the resected metaphyseal surface. This makes it possible to move the entire humeral joint part towards the humerus, whether the prosthesis is an anatomical prosthesis (anchoring element intended to receive a replacement humeral head) or a reverse shoulder prosthesis (anchoring element intended to receive a cup). This movement of the joint towards the humerus allows, when this is not the case for a prosthesis according to the prior art, a movement of the center of rotation of the joint towards the humerus so as to reproduce an anatomical situation in which the center of rotation of the joint is located at the level of the humerus and not at the level of the glenoid.

[0008] According to other optional characteristics of the humeral anchoring element taken alone or in combination: - The proximal collar is intended to extend substantially parallel to a plane in which the resected metaphyseal surface extends, - the proximal face of the proximal collar is intended to extend into the humerus at a distance of between 1 and 10 millimeters below the resected metaphyseal surface, preferably between 1 and 5 millimeters below the resected metaphyseal surface, - the main body is intended to extend only in a metaphyseal part of the humerus, the main body comprising a peripheral retention system formed by several peripheral anchoring plates separated from each other and intended to extend from the proximal collar towards a distal part of the humerus, two adjacent peripheral anchoring plates extending in planes not parallel to each other, - the peripheral anchoring plates extend in a direction substantially perpendicular to a plane in which the proximal face of the proximal collar extends, - the peripheral anchor plates are of irregular width along their direction of extension, - the main body comprises at least one stabilizing pad intended to extend from the proximal collar towards a distal part of the humerus, - the stabilizing pad extends in a direction substantially perpendicular to a plane in which the proximal face of the proximal collar extends, - the stabilizing pad comprises retention grooves extending substantially parallel to a longitudinal axis of the stabilizing pad, - the stabilization pad is a hollow body open at its distal end and comprises a plurality of through-holes provided in its wall, - the stabilizing pad is a hollow tubular body open at its proximal end and includes a thread provided on an internal surface of the stabilizing pad, and - the stabilizing pad comprises at least one lateral crown extending from an external face of the stabilizing pad in a direction substantially perpendicular to a longitudinal axis of the stabilizing pad.

[0009] The invention also relates to a humeral joint part of a shoulder prosthesis comprising a humeral anchoring element according to the invention.

[0010] The humeral joint part may comprise a replacement humeral head, and advantageously a spacer placed between the humeral anchoring element and the replacement humeral head.

[0011] Alternatively, the humeral joint part may comprise a cup for receiving a glenosphere.

[0012] The invention also relates to a shoulder prosthesis comprising a humeral joint part according to the invention.

[0013] The shoulder prosthesis can be an anatomical prosthesis or a reverse prosthesis. Brief description of the figures

[0014] The invention will be better understood on reading the following description given solely by way of example and with reference to the appended drawings in which:

[0015] [Fig-1] is a first perspective view of a humeral anchoring element according to the invention,

[0016] [Fig.2] is a second perspective view of a humeral anchoring element according to the invention,

[0017] [Fig.3] is a side view of a humeral anchoring element according to the invention,

[0018] [Fig.4] is a longitudinal sectional view of a humeral anchoring element according to the invention,

[0019] [Fig.5] is an exploded and perspective view of a humeral joint part according to a first embodiment of the invention,

[0020] [Fig.6] is an assembled and side view of the humeral joint part according to the first embodiment of the invention,

[0021] [Fig.7] is an exploded and perspective view of a humeral joint part according to a second embodiment of the invention,

[0022] [Fig.8] is an exploded and perspective view of a reverse shoulder prosthesis according to the invention,

[0023] [Fig.9] is an assembled and side view of a reverse shoulder prosthesis according to the invention,

[0024] [Fig. 10] is a side view of a humeral joint part according to the second embodiment of the invention implanted in a humerus. Detailed description

[0025] Reference is now made to Figures 1 to 4 illustrating a humeral anchoring element 2 of a humeral articular part 4 or 4' (see Figures 5 to 9) of a shoulder prosthesis (see Figures 8 and 9: exploded and assembled views of a reverse shoulder prosthesis). By humeral anchoring element is meant a part of a humeral articular part intended to be implanted in a cavity formed in a proximal end of a humerus, whether the humeral articular part is that of an anatomical or reverse shoulder prosthesis. The humeral anchoring element 2 can be made from a biocompatible metal such as a titanium alloy or stainless steel.

[0026] The humeral anchoring element 2 comprises a main body 8 intended to be inserted inside the humerus from a resected metaphyseal surface 10 (see [Fig.10]). It also comprises a proximal collar 12 placed at a proximal end of the main body 8 and which may be intended to extend substantially parallel to the resected metaphyseal surface 10.

[0027] A proximal face 14 of the proximal collar 12 extends into the humerus and below the resected metaphyseal surface 10. This means that the proximal end of the humeral anchoring element 2, intended to be placed as close as possible to the proximal end of the humerus, is located inside the humerus and below the plane formed by the resected metaphyseal surface 10. This makes it possible, as explained above, to “bury” the humeral anchoring element 2 in the humerus and therefore to move the humeral joint part and consequently the shoulder prosthesis towards the humerus, thus making it possible to place the center of rotation of the joint as close as possible to the humerus.

[0028] The proximal face 14 of the proximal collar 12 may for example extend into the humerus at a distance of between 1 and 10 millimeters below the surface resected metaphyseal 10, preferably between 1 and 5 millimeters below the resected metaphyseal surface.

[0029] The proximal collar 12 has a diameter of between 30 and 48 millimeters.

[0030] Advantageously, the main body 8 extends only in a meta portion physeal of the humerus 16. This means that the anchoring element 2 is devoid of a medullary anchoring rod. This is particularly advantageous, as explained above, for patients with a healthy metaphyseal part of the humerus and which can serve as an anchoring base for the humeral anchoring element 2 which will in particular be able to be placed in support against the calcar of the humeral head which is advantageously preserved at the time of bone resection.

[0031] The main body 8 may comprise a peripheral anchoring system formed by several peripheral anchoring plates 18 separated from each other, five in the example shown in the figures, intended to extend from the proximal collar 12 towards a distal part of the humerus 16. In the example illustrated, the latter extend from the proximal collar 12 substantially perpendicularly to a plane in which the proximal face 14 of the proximal collar 12 extends, two adjacent peripheral anchoring plates 18 extending in planes that are not parallel to each other. The advantage of using a peripheral anchor is to carry out said anchoring in the cortical part of the humerus which is the densest part of the bone. Thus, the anchoring of the humeral anchoring element 2 in the humerus 16 is optimized by interaction with the hardest part of the humerus 16.The placement of peripheral anchor plates 18 with adjacent plates not extending in mutually parallel planes makes it possible to prevent rotation of the anchor element 2 in the humerus 16.

[0032] Advantageously, the peripheral anchoring plates 18 may be of irregular width along their direction of extension. This is observed in the figures in which recesses 20 are present on either side of the peripheral extension plates 18 on the sides of the latter. These irregularities make it possible to ensure good anchoring of the humeral anchoring element 2 in the bone.

[0033] Preferably, one or more portions of the sides of the peripheral anchoring plates extend in a direction parallel to a direction of extension of the proximal face 14 of the proximal collar 12. This is visible in the figures in which each side of each peripheral anchoring plate 18 comprises three portions extending in such a direction. This once again promotes the anchoring of the anchoring element 2 in the humerus 16.

[0034] The length of the peripheral anchoring plates 18 is advantageously between 12 and 20 millimeters.

[0035] The main body 8 may comprise a stabilizing pad 22, placed in position central in the example of the figures, intended to extend from the proximal collar 12 towards a distal part of the humerus 16. In the example illustrated, the latter extends from the proximal collar 12 substantially perpendicularly to a plane in which the proximal face 14 of the proximal collar 12 extends. This stabilizing stud 22 has the purpose of preventing the anchoring element 2 and therefore the articular part 4 or 4' from tipping over in the humerus 16.

[0036] The length of the stabilizing pad is advantageously between 14 and 30 millimeters.

[0037] The stabilizing pad 22 may advantageously comprise retention grooves 24 extending substantially parallel to a longitudinal axis of the stabilizing pad 22. The latter make it possible to optimize the anti-rollover function of the stabilizing pad 22.

[0038] The stabilizing pad 22 may further be a hollow body open at its distal end (potentially at its proximal end and at its distal end) and comprise through-orifices 26 formed in its wall. These allow the interior of the stabilizing pad 22 to be connected to the exterior of the latter. This allows bone colonization and vascularization of the portion of bone located inside the stabilizing pad 22. This vascularization allows a consistent bone to be maintained inside the stabilizing pad 22, which optimizes the stabilization of the humeral anchoring element 2 in the humerus 16 by allowing anchoring from the inside of the stabilizing pad 22.

[0039] The stabilizing stud 22 may furthermore be a hollow body open at its proximal end (potentially at its proximal end and at its distal end) and comprise a thread 27 provided on an internal surface of the stabilizing stud 22. This thread 27 allows the removal of the humeral anchoring element 2 from the humerus 16 if necessary and by screwing in a tool for extracting the humeral anchoring element 2. It would be possible to use a fixing system other than a thread, such as a system of notches or notches.

[0040] The stabilizing pad may further comprise at least one lateral crown 25 (two in the figures) extending from an external face of the stabilizing pad 22 in a direction substantially perpendicular to a longitudinal axis of the stabilizing pad 22. It also makes it possible to optimize the anchoring of the humeral anchoring element 2 in the bone. The lateral crown 25 may further comprise notches aligned with the retention grooves 24 in order to preserve the function of the latter. The retention grooves are generally not continuous in order to have bone positioned between the portions of retention grooves 24 in order to further avoid rotation of the humeral anchoring element 2.

[0041] The humeral anchoring element 2 may further comprise a recess 28 able to form a conical fixation system intended to receive another part of a humeral articular part 4 or 4' (cup or spacer) as will be described later.

[0042] The proximal collar 12 may further comprise suture holes 46 (illustrated in FIGS. 1 to 4) making it possible to attach the soft parts of the bone to the humeral anchoring element 2.

[0043] [Fig. 5] illustrates a humeral joint part 4 according to a first embodiment of the invention and in the case where the shoulder prosthesis is an anatomical prosthesis, that is to say reproducing the shape of the anatomical joint. The humeral joint part 4 comprises, in addition to the humeral anchoring element 2, a spacer 30 intended to be arranged in the recess 28. The spacer 30 comprises a fixing stud 32 intended to receive a replacement humeral head 34.

[0044] [Fig. 6] illustrates a humeral joint part 4 according to the first embodiment of the invention and in the case where the shoulder prosthesis is an anatomical prosthesis, the humeral joint part 4 being assembled. The spacer 30 is placed in the recess 28 and the receiving stud 32 is inserted into a fixing orifice provided in the replacement humeral head 34.

[0045] [Fig. 7] illustrates a humeral joint part 4' according to a second embodiment of the invention. In this embodiment, the humeral joint part 4' is that of a reverse shoulder prosthesis 6 visible in [Fig. 8]. A cup 36 is intended to be mounted on the humeral anchoring element 2. This cup 36 comprises, at its end placed facing the glenoid, a concave surface intended to receive a glenosphere 40 (visible in Figures 8 and 9). Cups of different heights can be used with the same humeral anchoring element 2.

[0046] In this embodiment, a base 38 of the cup 36 is intended to be placed in the recess 27. The base 38 may be conical in shape and be quite wide, for example with a diameter at the gauge plane of between 15 and 30 millimeters.

[0047] The cup 36 is advantageously as wide as possible in order to provide the deepest possible concave surface. This makes it possible to have a layer of polyethylene in the concave surface, with a thickness for example equal to 4 millimeters, against which the glenosphere 40 is placed while allowing the glenosphere 40 to be placed as deep as possible in the concave surface.

[0048] Figures 8 and 9 illustrate a reverse shoulder prosthesis 6, respectively in exploded view ([Fig.8]) and in assembled view ([Fig.9]). It comprises the humeral articular part 4', and a glenoid articular part comprising in the illustrated example the glenosphere 40, a metaglene 42 intended to be fixed in the glenoid and on which the glenosphere 40 is fixed. Several anchoring screws 44 are intended to be used to fix the metaglene 42 in the glenoid.

[0049] [Fig. 10] illustrates, as described above, a proximal portion of a humerus 16 having a resected metaphyseal surface 10 and a humeral articular part 4' according to the second embodiment of the invention. As can be seen in the figure, the entirety of the anchoring element 2 is arranged inside the humerus 16, the proximal face 14 of the proximal collar 12 extends below a plane in which the resected metaphyseal surface 10 extends. List of references

[0050] 2: humeral anchoring element

[0051] 4, 4': humeral articular part

[0052] 6: reverse shoulder prosthesis

[0053] 8: main body

[0054] 10: resected metaphyseal surface

[0055] 12: proximal collar

[0056] 14: proximal face

[0057] 16: humerus

[0058] 18: peripheral anchoring plates

[0059] 20: recesses

[0060] 22: stabilization stud

[0061] 24: retention grooves

[0062] 25: lateral crowns

[0063] 26: through holes

[0064] 27: tapping

[0065] 28: recess

[0066] 30: spacer

[0067] 32: fixation stud

[0068] 34: replacement humeral head

[0069] 36: cup

[0070] 38: base

[0071] 40: glenosphere

[0072] 42: metaglene

[0073] 44: anchoring screw

[0074] 46: suture holes

Claims

Claims

1. Humeral anchoring element (2) of a humeral joint part (4, 4') of a shoulder prosthesis, the humeral anchoring element (2) being characterized in that it comprises: - a main body (8) intended to be inserted inside a humerus (16) from a resected metaphyseal surface (10), and - a proximal collar (12) forming a proximal end of the humeral anchoring element (2) and placed at one end of the main body (8), a proximal face (14) of the proximal collar (12) extending into the humerus (16) and below the resected metaphyseal surface (10).

2. Humeral anchoring element (2) according to claim 1, wherein the main body (8) is intended to extend only in a metaphyseal part of the humerus (16), the main body (8) comprising a peripheral anchoring system formed by several peripheral anchoring plates (18) separated from each other and intended to extend from the proximal collar (12) towards a distal part of the humerus (16), two adjacent peripheral anchoring plates (18) extending in planes not parallel to each other.

3. A humeral anchoring element (2) according to claim 2, wherein the peripheral anchoring plates (18) are of irregular width along their direction of extension.

4. A humeral anchoring element (2) according to any preceding claim, wherein the main body comprises at least one stabilizing stud (22) intended to extend from the proximal collar (12) towards a distal portion of the humerus (16).

5. A humeral anchoring element (2) according to claim 4, wherein the stabilizing stud (22) comprises retention grooves (24) extending substantially parallel to a longitudinal axis of the stabilizing stud (22).

6. Humeral anchoring element (2) according to any one of claims 4 or 5, in which the stabilizing stud (22) is a hollow body open at its distal end and comprises a plurality of through-orifices (26) formed in its wall.

7. Humeral anchoring element (2) according to any one of claims 4 to 6, in which the stabilizing stud (22) is a hollow body of tubular shape open at its proximal end and comprises a thread (27) provided on an internal surface of the stabilizing stud (22).

8. Humeral anchoring element (2) according to any one of claims 4 to 7, wherein the stabilizing pad (22) comprises at least one lateral crown (25) extending from an external face of the stabilizing pad (22) in a direction substantially perpendicular to a longitudinal axis of the stabilizing pad (22).

9. Humeral joint part (4, 4') comprising a humeral anchoring element (2) according to any one of the preceding claims.

10. Shoulder prosthesis comprising a humeral joint part according to claim 9.

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