FR2939639A1 - Shoulder prosthesis for prosthetic assembly, has platform supported against proximal end of humeral prosthetic rod that is engaged in medullary cavity of humerus, and through holes distributed on periphery of proximal end of rod - Google Patents

Abstract

This shoulder prosthesis (2) comprises a prosthetic humeral stem (3) intended to be engaged in the medullary canal of a humerus (4), and a platform (6) intended to bear against the proximal end of the stem prosthetic humeral, the platform (6) comprising a plurality of through holes for the passage of suture son (13), the holes being intended to be distributed on the periphery of the proximal end of the prosthetic humeral stem.

Description

The present invention relates to a shoulder prosthesis. During fractures of the upper part of a humerus, and in particular of one of the tuberosities of the latter, it is known to bring the different bone fragments together and fix them around a shoulder prosthesis.

A shoulder prosthesis comprises in known manner a humeral part engaged in the medullary canal of the humerus and reproducing the upper end of the latter, and possibly a glenoid implant if the surface of the glenoid is damaged. The attachment of the various bone fragments is generally performed using suture son connecting the different bone fragments to the main body of the humerus. The fixation must be stable, that is to say, allow no mobility of the bone fragments relative to the main body of the humerus, to obtain a satisfactory bone consolidation. A first method of fixation of bone fragments is to drill through holes in a non-fractured area of the humerus, these through holes serving as attachment points for the sutures for connecting the different bone fragments to the main body of the bone. humerus However, such a method of fixation leads to degradation of the humerus and does not allow to ensure satisfactory fixation of bone fragments. A second method of fixing the bone fragments consists in implanting in the humerus a prosthetic humeral stem comprising an external fin, the fin comprising bores arranged to allow the passage of suture son.

However, the position of the fin and therefore the holes in the latter do not allow a satisfactory fixation of external bone fragments on the main body of the humerus because these external bone fragments are located in the same plane as the fin. In addition, the holes in the fin form sharp edges likely to cut the son of sutures engaged in these holes. The present invention aims to remedy all or part of these disadvantages. The technical problem underlying the invention therefore consists in providing a shoulder prosthesis which ensures satisfactory bone consolidation of the bone fragments of the humerus, while avoiding bone degradation of the humerus.

For this purpose, the present invention relates to a shoulder prosthesis comprising a prosthetic humeral stem intended to be engaged in the medullary canal of a humerus, characterized in that it comprises a platform intended to bear against the proximal end of the prosthetic humeral stem, the platform comprising a plurality of through holes for the passage of suture son, the holes being intended to be distributed on the periphery of the proximal end of the prosthetic humeral stem. The presence of a plurality of holes distributed over the periphery of the proximal end of the prosthetic humeral stem makes it possible to obtain suture fixation points distributed over the periphery of the prosthetic humeral stem, and thus to provide fixation. satisfactory bone fragments whatever their position. As a result, the prosthesis according to the invention provides satisfactory bone healing of the bone fragments of the humerus. Preferably, at least one of the through bores extends perpendicular to the support plane of the platform on the proximal end of the prosthetic humeral stem. Advantageously, the through holes are regularly distributed over the periphery of the platform. According to one embodiment of the invention, the ends of each hole are chamfered. According to another embodiment of the invention, the platform and the proximal end of the prosthetic humeral stem are arranged to prevent relative rotation between them. Advantageously, the platform has a closed contour. Preferably, the shoulder prosthesis comprises a strapping arranged to be sewn with needles and surgical sutures, the strapping being intended to be positioned around a non-fractured area of the humerus. The presence of such strapping makes it possible to obtain, with the platform, points for fixing the suture threads on either side of the bone fragments, and therefore to further improve the fixation of the latter. According to one embodiment of the invention, the strapping is a ribbon whose ends are intended to be folded towards one another so as to form a strapping.

Advantageously, the ribbon comprises an opening in which is intended to be introduced one end of the ribbon. Preferably, the opening is formed substantially at the end of the ribbon opposite to that intended to be introduced into the opening.

According to one embodiment of the invention, the end of the ribbon intended to be introduced into the opening has a smaller section than that of the ribbon. According to another embodiment of the invention, the end of the ribbon opposite to that intended to be introduced into the opening comprises gripping means. According to yet another embodiment of the invention, the ribbon is a textile ribbon. Preferably, the ribbon comprises a wire extending therealong. Advantageously, the shoulder prosthesis comprises a prosthetic humeral head intended to be fixed on the proximal end of the prosthetic humeral stem, the platform being intended to be clamped between the prosthetic humeral head and the prosthetic humeral stem. The present invention also relates to a prosthetic assembly comprising a prosthesis according to the invention and at least one suture comprising, at one of its ends, a surgical needle. According to one embodiment of the invention, the end of the suture opposite the needle comprises a loop arranged to allow the passage of the surgical needle. According to another embodiment of the invention, both ends of the suture are attached to the needle. Anyway, the invention will be better understood with the aid of the description which follows with reference to the appended schematic drawing showing, by way of non-limiting example, an embodiment of this shoulder prosthesis. Figure 1 is an exploded view, in perspective, of a shoulder prosthesis according to the invention. Figure 2 is a perspective view of the prosthesis of Figure 1 in the use position. Figure 3 is a top view of the ribbon of the prosthesis of Figure 1.

Figures 4 and 5 are views of the ribbon in different steps of forming the strapping. Figure 6 is a top view of a suture according to a first embodiment of the invention.

Figure 7 is a top view of a suture according to a second embodiment of the invention. Figures 1 and 2 show a shoulder prosthesis 2 comprising a prosthetic humeral stem 3 intended to be engaged in the medullary canal of a humerus 4. Advantageously, the prosthetic humeral stem 3 is fixed in the medullary canal of the humerus by orthopedic cement. The prosthetic humeral stem 3 is preferably made of titanium alloy or stainless steel. It should be noted that the proximal end 5 of the prosthetic humeral stem 3 is intended to protrude from the humerus 4.

The shoulder prosthesis 2 also comprises a platform 6 intended to bear against the proximal end 5 of the prosthetic humeral stem. The platform 6 is advantageously made of very high molecular weight polyethylene or metal, for example titanium alloy or stainless steel.

The platform 6 has a closed contour complementary to that of the proximal end 5 of the prosthetic humeral stem 3. This closed contour is substantially oblong so as to prevent relative rotation between the platform 6 and the prosthetic humeral stem 3. The platform 6 comprises a plurality of through holes 7 for the passage of needles and suture son, the holes 7 being distributed on the periphery of the platform 6. Preferably, the platform comprises between 5 and 12 through holes 7. Each through hole 7 extends perpendicularly to the support plane of the platform 6 on the proximal end 5 of the prosthetic humeral stem 3. It should be noted that the ends of each piercing 7 are chamfered so as not to form sharp edges likely to cut the son of sutures engaged in this piercing through. The shoulder prosthesis 2 further comprises a strapping 8 intended to be positioned around a non-fractured area of the humerus 4 and arranged to be sewn with needles and surgical sutures.

As shown in FIG. 3, the strapping is a ribbon 8 made of biocompatible braided or knitted fabric, the ends of which are intended to be folded towards each other so as to form a strapping. Advantageously, the ribbon 8 is resorbable and is for example made of polylactide (PLA) or L pure polylactide (PLLA). However, the ribbon 8 may not be absorbable. When it is not absorbable, the ribbon 8 is preferably made of polyester terephthalate, polyethylene or polyvinylidene fluoride. The width of the ribbon 8 is preferably between 5 and 20 mm, while its length is preferably between 10 and 20 cm.

The ribbon 8 comprises an oblong aperture 9 forming a buttonhole formed substantially at one end of the latter. The opening 9 extends perpendicular to the plane defined by the ribbon 8 and has a width substantially corresponding to half the width of the ribbon 8. The ribbon 8 comprises, at its end opposite the opening 9 forming a buttonhole, an end portion 10 having a width less than that of the main portion of the ribbon 8, the width of this end portion 10 substantially corresponding to that of the opening 9 so as to allow insertion of the end portion 10 in the latter.

The end of the ribbon 8 turned on the side of the buttonhole opening 9 comprises breakable gripping means arranged to allow to exert traction on the ribbon 8. The gripping means comprise a pull wire 11 secured to the end ribbon turned towards the opening 9.

Advantageously, when it is not absorbable, the ribbon 8 comprises a metal wire extending along the latter, preferably in the middle. This wire constitutes a radiographic marker for detecting a possible movement of the ribbon, or even its rupture. The shoulder prosthesis 2 also comprises a prosthetic humeral head 12 intended to be implanted on the proximal end 5 of the prosthetic humeral stem 3, the platform 6 being intended to be sandwiched between the prosthetic humeral head 12 and the prosthetic humeral stem 3 The present invention also relates to a prosthetic assembly comprising a shoulder prosthesis 2 and several suture threads 13, 13 ', two embodiments of these suture threads being respectively shown in FIGS.

Each suture 13, 13 'may be made of absorbable material, for example polyester terephthalate, polybutylene or polyamide, or nonabsorbable material, for example lactomer or polydlyoaxone.

The length of each suture 13, 13 'is preferably between 30 and 90 mm and the diameter of the latter is advantageously between 0.5 and 2 mm. Each suture 13, 13 'has at one of its ends a surgical needle 14 curved extending preferably on a semicircle or a quarter circle. Each surgical needle 14 advantageously has a radius of curvature of between 12 and 26 mm. Each surgical needle 14 is preferably made of stainless steel. According to the first embodiment shown in FIG. 6, the two ends of the suture 13 are crimped onto the surgical needle 14. Such suture threads 13 make it easier to knot the yarn at the end of the insertion of this thread. last, two strands of son being available when the suture is cut under the needle. According to the second embodiment shown in FIG. 7, the end of the suture 13 'opposite to the surgical needle 14 comprises a loop 15 arranged to allow the passage of the surgical needle 14. The method of using the prosthetic assembly according to the invention will now be described. The method of using the prosthetic assembly comprises the following steps: a) positioning the ribbon 8 around a non-fractured portion of the humerus 4, preferably at the upper edge of the insertion of the large pectoral b) fold the ends of the ribbon 8 towards each other, c) insert the end portion 10 of the ribbon into the opening 30 forming the buttonhole 9, d) stretch the ribbon 8 by simultaneously exerting a pull on the pull wire 11 and on the end portion 10, as shown in FIG. 4, e) fold the end portion 10 on the ribbon 8, as shown in FIG. 5, f) sew the end portion 10 on the ribbon 8 so as to form a strapping around the humerus 4, g) cut the traction wire 11, h) engaged the prosthetic humeral stem 3 in the medullary canal 5 of the humerus 4 which was eventually prepared to receive it, i) introduce a suture thread e 13 'in a through hole 7 of the platform 6, j) pass the surgical needle 14 suture 13' in the loop 15 of the latter and exert a traction on the needle so as to fix the thread suture on the platform 6, k) repeat as much faith as necessary steps i) and j), I) position the platform 6 on the proximal end 5 of the prosthetic humeral stem 3, m) position the bone fragments of the humerus on the latter, n) fix the bone fragments 16 on the main part of the humerus 4 by surrounding them with the suture son 13 'fixed on the platform 6, the end of each suture 13' comprising the surgical needle 14 being knotted either in a piercing 7 of the platform 6 or on the strapping 8, 20 o) cutting each suture 13 'at its surgical needle 14 so as to remove the latter p) forcing the prosthetic humeral head 12 into an opening opening 17 formed in the proximal end 5 of the prosthetic humeral stem 3. It should be pointed out that steps i) and j) would be different if suture threads 13 were used in place of suture threads 13 ' . The possibility of securing sutures on the platform 6 and on the strapping 8 makes it possible to obtain anchoring points for the threads on either side of the bone fragments 16, and therefore to improve the fixation of these on The humerus 4 results in stable fixation of the bone fragments, and thus satisfactory bone healing of the humerus. It should be noted that the shoulder prosthesis 2 according to the invention also makes it possible to avoid perforation in the healthy parts of the humerus in order to fix the various bone fragments 16, and therefore a degradation of the latter.

As goes without saying, the invention is not limited to the sole embodiment of this shoulder prosthesis, described above as an example, it encompasses all the variants. This is particularly the case that the holes 7 could be regularly distributed on the periphery of the platform 6.

Claims (18)

REVENDICATIONS1. Prosthetic shoulder (2) comprising a prosthetic humeral stem (3) intended to be engaged in the medullary canal of a humerus (4), characterized in that it comprises a platform (6) intended to bear against the proximal end (5) of the prosthetic humeral stem, the platform (6) comprising a plurality of through bores (7) for the passage of suture threads (13, 13 '), the bores being intended to be distributed over the periphery of the proximal end of the prosthetic humeral stem. 2. Shoulder prosthesis according to claim 1, wherein the axis of at least one of the through holes (7) extends perpendicularly to the support plane of the platform (6) on the proximal end ( 5) of the prosthetic humeral stem (3). 3. Shoulder prosthesis according to claim 1 or 2, wherein the through holes (7) are distributed on the periphery of the platform (6). 4. Shoulder prosthesis according to one of claims 1 to 3, wherein the ends of each bore (7) are chamfered. 5. Shoulder prosthesis according to one of claims 1 to 4, wherein the platform (6) and the proximal end (5) of the prosthetic humeral stem (3) are arranged to prevent relative rotation between them. The shoulder prosthesis according to one of claims 1 to 5, wherein the platform (6) has a closed contour. 7. Shoulder prosthesis according to one of claims 1 to 6, which comprises a strapping (8) arranged to be sewn with needles and surgical sutures, the strapping being intended to be positioned around a non-surgical area. fractured humerus (4). 30 8. Shoulder prosthesis according to claim 7, wherein the strapping is a ribbon (8) whose ends are intended to be folded towards each other so as to form a strapping. 9. The shoulder prosthesis according to claim 8, wherein the ribbon (8) comprises an aperture (9) in which is intended to be introduced an end (10) of the ribbon. 10. Shoulder prosthesis according to claim 9, wherein the opening (9) is formed substantially at the end of the ribbon opposite to that intended to be introduced into the opening (9). The shoulder prosthesis according to claim 9 or 10, wherein the end of the ribbon (8) for insertion into the aperture (9) has a smaller cross-section than that of the ribbon. 12. Shoulder prosthesis according to claim 9 to 11, wherein the end of the ribbon (8) opposite to that intended to be introduced into the opening (9) comprises gripping means (11). 10 13. Shoulder prosthesis according to one of claims 8 to 12, wherein the ribbon (8) is a textile ribbon. The shoulder prosthesis according to one of claims 8 to 13, wherein the ribbon (8) comprises a wire extending therealong. The shoulder prosthesis according to one of claims 1 to 14, which comprises a prosthetic humeral head (12) intended to be fixed on the proximal end of the prosthetic humeral stem (3), the platform (6) being intended to be clamped between the prosthetic humeral head and the prosthetic humeral stem. 16. Prosthetic assembly comprising a shoulder prosthesis (2) according to one of claims 1 to 15, and at least one suture (13, 13 ') having, at one of its ends, a surgical needle (14). The prosthetic assembly of claim 16, wherein the end of the suture (13 ') opposite the surgical needle (14) comprises a loop (15) arranged to allow passage of the surgical needle (14). ). The prosthetic assembly of claim 16, wherein both ends of the suture (13) are attached to the needle (14).