FR2675041A3 - Fixation bracket for the male part of a hip prosthesis ball joint - Google Patents

Abstract

The present invention relates to the fixation brackets for the male part of a femoral prosthesis ball joint, capable of being fixed in the medullary cavity of a femur. The fixation bracket 1 according to the invention is characterised essentially by the fact that it comprises a shaft 4 and a fixation head 5 integral, via its base 15, with an end 6 of the shaft, the fixation head being capable of cooperating with the male part of the ball joint and defining a fixation axis 11, the shaft 4 comprising two consecutive parts 7, 8 which join in a junction section 10, a first part 7 of curved shape and a second part 8 which is substantially rectilinear and has a cross-section increasing from its free end as far as the junction section, the curved part 7 of the shaft being delimited laterally, on its side 13 situated in its concave face, by a concave surface 14 connecting the junction section 10 to the base 15 of a fixation head 5, and, on its side 12 situated in its convex face, by two consecutive surfaces, namely a convex surface 16 and a concave surface 17, connecting the junction section 10 to the base 15 of the fixation head.

Description

Male part fixing lug
a femoral prosthesis
The present invention relates to the fixing lugs for the ball joints of prostheses of the femoral type, in 1 instance for the male part of these ball joints.

It is already known a certain number of embodiments of fixing lugs to support the male part of a prosthetic ball joint of the femoral type, that is to say of legs intended for 8trie arranged by plugging in the medullary canal of the femur. Current embodiments include a tail terminated by a fixing head on which is disposed, generally by a conical type embedding, the male part of a ball joint essentially consisting of a portion of a sphere,
The problems which arise for the fixing of such a leg in a femur are the adaptation to the real shape and to the dimensions of lotos, the solidity and the duration of the fixing as it is. quite obvious that one cannot often intervene to consolidate it, but also the perfect positioning of the leg in laos, in particular compared to the iliac bone.

 These tabs are thus formed to meet as many of the conditions defined for their use as possible.

However, despite all the care taken in their definition, the prostheses of which these legs are a part are sometimes subjected to much more intense efforts than those which were normally expected.

 The present invention therefore aims to achieve a leg structure for hip prosthesis, which adapts perfectly to the medullary canal of the femur and can withstand very great efforts, so as not to be able to undergo parasitic depressions.

 More specifically, the subject of the present invention is a fixing lug for the male part of a femoral prosthesis ball, capable of being fixed in the medullary canal of a femur, said lug comprising at least one tail and a fixing head. secured by its base to one end of said shank, the fixing head being able to cooperate with the male part of the ball joint and defining a fixing axis, said shank comprising two consecutive parts joining in a substantially junction section planar, a first part of curved shape and a second part substantially rectilinear along a direction axis and having a section increasing from its free end to said junction section, characterized in that the curved part of the tail is delimited laterally , on its side located in its concave face, by a concave surface connecting the junction section to the base of said fixing head and, s on its side situated in its convex face, by two consecutive surfaces respectively convex and concave connecting said junction section to the base of said fixing head.

 Other characteristics and advantages of the present invention will appear during the following description given with reference to the drawing annexed by way of illustration, but in no way limiting, in which the single figure represents a side view of an embodiment of a tab according to the invention.

 The single figure shows a fixing lug 1 for the male part of a ball joint of a femoral prosthesis. This leg 1 essentially comprises two elements, a #premier element constituting a tail 4 able to be inserted into the medullary canal of a femur, and a second constituting a fixing head 5 secured, by its base 15, to one end 6 of the tail 4, this head 5 being intended to cooperate in a known manner with the male part of the ball joint, for example a portion of sper.

 The tail 4 is essentially constituted by an oblong piece comprising two consecutive parts joining in a substantially flat junction section 10. A first part 7, that of which the end opposite the junction section is merged with the end 6 of the tail secured to the fixing head, is of curved shape. The second part 8 is substantially rectilinear along a direction axis 9 and of a section increasing from its free end to the junction section 10. The direction axis 9 is substantially perpendicular to the junction section of the two parts of tail.

 The fixing head 5 defines a fixing direction along an axis 11 which, in known manner, makes with the direction axis 9 a determined physiological angle.

 According to an important characteristic of the invention, the curved part 7 is delimited laterally, on its first side 13 situated in its concave face, by a concave surface 14 connecting the junction section 10 to the base 15 of the fixing head 5 and , on its second dimension '12 located in its convex face, by two consecutive surfaces respectively convex 16 and concave 17 connecting the junction section to the base 15 of the fixing head.

 Thanks to the structure of its tail, in particular of the curved part 7, the femoral prosthesis leg according to the invention can be perfectly implanted in the medullary canal and can resist parasitic forces of insertion into this canal. In fact, the concave surface 14 on the first side 13 and the convex surface 16 on the second side 12 laterally hold the tab, while the concave surface 17 on this second side 12 allows the tab to rest either on the portion d 'upper epiphysis of the femur which was kept by the practitioner during the operation for the placement of the prosthesis, ie on the upper edge of the hard bone of the diaphysis. This concave surface 17 thus acts jointly with the rectilinear part 8 of the tail, of substantially conical shape, to ensure longitudinal retention of the tab and prevent it from sinking into the medullary canal when the prosthesis is subjected to longitudinal stresses. intense sinking.

Claims (1)

 CLAIM  Fixing tab (1) for the male part of a femoral prosthesis ball, capable of being fixed in the medullary canal of a femur, said tab comprising at least one tail (4) and a fixing head (5) integral , by its base (15), of one end (6) of said tail, the fixing head being able to cooperate with the male part of the ball joint and defining a fixing axis (11), said tail comprising two consecutive parts (7,8) joining along a substantially planar junction section (10), a first part (7) of curved shape and a second part (8) substantially rectilinear along a direction axis (9) and having a section increasing from its free end up to said junction section, characterized in that the curved part (7) of the tail is delimited laterally, on its side (13) located in its concave face, by a concave surface (14) connecting the junction section (10) at the base (15) of said fixing head tion (5) and, on its side (12) located in its convex face, by two consecutive surfaces respectively convex (16) and concave (17) connecting said junction section (10) to the base (15) of the head fixing (5).