Hip prosthesis.

The present invention relates to a hip prosthesis.

currently used in surgery of hip prostheses which consist of three parts namely an acetabular cup, a metal femoral tail comprising a neck and a spherical femoral head integral or independent col.Ces dentures can be attached to the bone or by seal with plastic cement directly without cement by various more or less valid means.

They all require a more or less substantial widening of the bone weakens the latter, in particular at the acetabulum. In addition, the sealing cement can cause loosening after a variable time.

The present invention aims to improve outcomes for hip prostheses by proposing a cementless acetabular prosthesis, anchoring requires no digging bone

To this end this hip prosthesis comprising a cup acetabular external metal, of substantially hémishpérique, fixed in the pelvic bone, a core acetabular internally plastic, fitted into the acetabular cup outer metal, a tail femoral shaft fitted into the femoral a spherical head femoral acetabular engaged in the core internal and neck connection between the femoral head and tail, is characterized in that the acetabular cup outer metal is secured to a metal fin plane s'encastrant friction hard in slot of the ilium, the map of this fin forming, with the opening plane of the acetabulum, an angle of 50 to 80 ° and preferably about 65 °.

The internal cotyloid core of polyethylene may be symmetrical or asymmetrical has a plane with an acetabulum opening plane forming an angle ranging from 90 to 120 ° with the axis of the core cotyloïdien.Cette characteristic corrects a possible defect of anteversion or retroversion of the acetabulum.

The femoral neck is preferably removable and may be bent at an angle varying from 10 ° to 30 °. This arrangement allows to adjust and possibly correct anteversion or retroversion of the femoral tail.

hereinafter be described, by way of nonlimiting examples, various embodiments of the present invention, with reference to the accompanying drawings wherein:<ul><li>Figure 1 is a profile view of an up hip prosthesis, in the fin plane of the outer acetabular cup.</li><li>Figure 2 is a front view of the hip prosthesis in place.</li><li>Figure 3 is a view of the iliac bone, showing the slot of the cutting plane for receiving the fin.</li><li>Figure 4 is an elevational view of the metallic external cotyloid cup of the hip prosthesis according to the invention perpendicularly to the plane of the lateral retinaculum.</li><li>5 is a sectional view taken along the line VV in Figure 4, the inner acetabular polyethylene core being shown up in the outer metal shell.</li><li>Figure 6 is a view of external acetabular cup, taken from the left in Figure 4 and looking at the fin by the slice.</li><li>Figures 7 and 8 are sectional views of various core x acetabular polyethylene.</li><li>Figures 9 and 10 are diagrams showing removable femoral necks.</li></ul>

The hip prosthesis according to the invention which is shown in Figures 1 and 2, comprises essentially five parts, namely a cup acetabular external métalliquel fixed in the pelvic bone 4, a core acetabular internal plastic 2, fitted into the metallic outer cup 1, a femoral tail fitted in the shaft 5 femoral, femoral head a spherical core 7 housed in the internal cotyloid in plastic 2 and a femoral neck 8 providing a connection between the head 7 and the tail femoral 5.

According to the invention the outer metal acetabular cup 1 is embedded in the ilium and the ischium by means of a fin 9 which extends towards the greater sciatic notch and which is contained in a diametral plane P (Figure 5 ) of the outer hemispherical acetabular cup 1. This plane P forms with the frontal plane P1 containing the opening of the acetabular cup, an angle ª which is between 50 and 80 ° and is preferably equal to 65 °. This spoiler 9, thin, is fixed by fitting into a slot of the bone width substantially equal to the thickness of the fin 9 slot in which it holds by simply rubbing.

To improve the fixing of the anchoring fin 9 may be provided, on its peripheral edge 9, a sawtooth cut 11. Also the flap 9 can be pierced by one or more holes 12 through which can reconstitute the bone, by strengthening and anchoring the acetabular cup 1.

According to an additional feature of the invention the internal cotyloid core 2 polyethylene has a frontal plane anteversion, that is to say the one containing the opening of the cup, which forms an angle ranging from 90 ° to 120 ° xy axis with acetabular core as shown in figures 7 and 8. This arrangement allows to better adapt the hip prosthesis according to the invention particular implantation conditions encountered.

Hip prosthesis according to the invention may also advantageously comprise, as shown in Figures 9 and 10, a femoral 8 independent removable neck of the femur shank 5 and therefore interchangeable. This interchangeable femoral neck 8 may be rectilinear, of variable length as is shown in Figure 9, or it may be angled, with an angle ranging from 10 to 30 ° to allow a modification of the angle anteversion of the neck if necessary.