Hip prosthesis.

DESCRIPTION

The present invention relates to a hip prosthesis.

A hip prosthesis is currently used in surgery that consists of three pieces, namely a cotyloid cupoula, a femoral metabolic tail, comprising a neck and a spherical femoral head in solidarity or independent of the neck. These prostheses can be fixed to the bone either by anchoring thanks to the plastic cement or directly without cement by various means or less valid.

They all need a more or less important cupping of the bone that makes this last fragile, particularly at the level of the cootilla. In addition, the anchor with cement can carry de-shredding after a variable time.

The present invention aims to improve the results of hip prostheses by proposing a cotyloid prosthesis without cement whose anchorage does not require any bone cupping.

For this purpose, this hip prosthesis comprising a metabolic external cotyloid cuópula, in a substantially hemispherical manner, fixed in the iliac bone, an internal cotyloid bone of ploastic matter, embedded in the metabolic external cotyloid cupoula, a femoral tail embedded in the femoral diaphysis , a spherical femoral head fitted in the internal cotyloid bone and a neck of union between the head and the femoral tail, It is characterized in that the external metabolic cotyloid cupoula is in solidarity with a flat spoiler that is embedded by hard friction in a groove of the iliac bone, the plane of this spoiler forms with the opening plane of the cootilla an angle that ranges from 50 to 80 ° and preferably about 65 °.

The internal cotyloid bone in polyethylene can be symmetric or auon has an asymmetrical plane with an opening plane of the cootilla that makes an anonum that varies from 90^° to 120^° Cotyloid bone cone. This feature makes it possible to correct an eventual defect of anteversion or retroversion of the cootilla.

The femoral neck is preferably mobile and can be angled in an anonum that varies from 10^° to 30^°. This provision allows adjusting and possibly correcting a anteversion or a retroversion of the femoral tail.

Various forms of execution of the present invention, in relation to the annexed drawing in which:

Figure 1 is a profile view of a hip prosthesis in place, in the plane of the outer cotyloid cupola aleroon.

Figure 2 is a front view of the hip prosthesis in place.

Figure 3 is a view of the iliac bone, showing the cut plane of the groove intended to receive the spoiler.

Figure 4 is an elevational view of the metabolic external cotyloid cuópula of the hip prosthesis following the invention, perpendicular to the plane of the external spoiler.

Figure 5 is a sectional view taken in line with the VV line of Figure 4, the internal cotyloid bone in polyethylene was represented in its place in the external metal dome.

Figure 6 is a view of the external cotyloid dome, taken from the left on Figure 4 and looking at the wing by the cut.

Figures 7 and 8 are sectional views of various cotyloid bones in polyethylene.

Figures 9 and 10 are schematic views illustrating mobile femoral necks.

The hip prosthesis followed the invention that was represented in figures (1) and (2), essentially comprising five pieces, namely a metabolic external cotyloid cupoula (1) fixed in the iliac bone (4), an internal cotyloid bone in plastic material (2), embedded in the external metabolic cupoula (1), a femoral tail (5) embedded in the femoral diaphysis (6), a spherical femoral head (7) housed in the internal cotyloid bone in plastics (2) and a femoral neck (8) that ensures the union between the head (7) and the femoral tail (5).

The invention was followed by the external metal-shaped cotyloid dome (1) was embedded in the iliac wing and in the ischium by means of an aileron (9) that extends into the large ciaotic incisor and is contained in a diametral plane P (Figure 5) of the external (1) hemispherical cotyloid cuópula. This plane P forms, with the frontal plane P1 containing the opening of the cootilla, an aongle "a" that was shared between 50^° y80^° and that preferably equals 65^°. This spoiler (9), of soft thickness, was fixed by fitting into a bone groove of length substantially equal to the thickness of the spoiler (9), groove in which it is maintained by simple friction.

In order to improve the fixation of this anchor wing (9), a saw-shaped cut (11) can be provided at its peripheral edge (9). In addition, the wing (9) can be drilled with one or more holes (12) through which the bone can be reconstituted, thus reinforcing the anchoring of the cotyloid cupoula (1).

A complementary characteristic of the invention followed the internal cotyloid bone (2) in polyethylene has a frontal plane of anteversion, that is, the one that contains the opening of the cootilla, which makes an oangle that can vary from 90^° to 120^° with the xy axis of the cotyloid bone as represented in the firas (7) and (8). This arrangement allows the hip prosthesis to be better adapted according to the invention to the particular implantation conditions found.

The hip prosthesis followed the invention can also advantageously admit, in the way that it was represented in figures (9) and (10), a mobile femoral neck (8) independent of the femoral tail (5) and therefore interchangeable. This interchangeable femoral neck (8) can be rectilonear, of a variable length in the way that it is represented in figure (9) or auon can be bent, with an angle ranging from 10^° a30^°, in order to allow a modification of the anteversion angle of the neck if necessary.

012 398