Orthopedic implant in the form of a plate to be fixed between two bone parts

The invention relates to a plate fixed between two bone parts by way of screws engaged in holes formed in the thickness of the plate. The plate comprises an angled member or rib which is inclined according to an angle of between about 30° and 60° in relation to the plane defined by the plate. The angled member or rib has a hole for engaging a screw and is located in the central part of the width, over a determined part of the length of the plate, so that the screw brings the two bone parts into a compressive position.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US national phase of PCT application PCT/FR2009/051879, filed 2 Oct. 2009, published 8 Apr. 2010 as 2010/037985, and claiming the priority of French patent application 0856694 itself filed 2 Oct. 2008, whose entire disclosures are herewith incorporated by reference.

The invention relates to the technical field of orthopedic implants.

More particularly, the invention relates to a plate for arthrodesis or osteosynthesis adapted to be fixed between two bone parts.

In a manner known to one having ordinary skill in the art, this type of plate generally has holes for engaging screws, allowing arthrodesis between two bones or osteosynthesis between two bone fragments. This is, for example, the case for bones of the hand or foot, without however excluding other applications, particularly in the field of the spine. Depending on the pathology to be treated, these plates can have a general rectilinear or other geometric shapes.

From this state of the art, one of the objects the invention proposes to attain is to improve, in a sure and efficient manner, compression in a precise direction between the bone parts subjected to the plate.

To attain the given object to enhance the compression between the two relative bone parts, according to the invention, the plate has a formation that orients at least one screw at an angle with respect to a plane defined by the plate, the angle being between about 30° and 60°.

According to an advantageous embodiment, the formation is a tab that is angled according to an angle between 30° and 60°, and having a hole for engaging the screw. The angled tab results from a cut out and a deformation of a portion of the plate.

In another embodiment, the formation is a hole angled at an angle between 30° and 60° for engaging the screw.

Considering the problem to be solved, the formation is located on a determined portion of the length of the plate so that the screw ensures the compression of the two bone parts.

According to the invention, the plate1has at least one formation1aadapted to enable the positioning of at least one screw2, at an angle α of between 30° and 60° with respect to a plane of the plate (FIG. 2).

In one embodiment, the formation1ais an angled tab cut out and deformed from the plate. For example, the deformation is made with a cutting-punching operation. This angled tab has a hole1a1for a screw2. The angled tab1ais positioned along the length of the plate so that after the screw2is fitted to it, the screw ensures the compression together of the two bone parts, as indicated below in the description.

In another embodiment, to allow for an angular orientation of the screw2according to an angle between about 30° and 60° , the formation1acan be formed as an angled hole. It must be noted that the tab1aenables adaptation of the angle as a function of the pathology to be treated, given that it is possible to deform this tab at will. In other words, the angle can be adjusted over a few degrees by the surgeon in the operating room, using an appropriate tool.

With reference toFIGS. 3 and 4that show the positioning of the plate1between two bone parts O1and O2:Once the osteotomies have been carried out, a template of the plate, which does not have a guide formation, enables the position of this tab to be determined.After determining the position of the tab, the surgeon makes a corresponding recess with the appropriate rasp.Once the plate having the tab has been positioned, the surgeon sets one or two screws3, on a side of the site of the osteosynthesis of the arthrodesis toward the tab. A temporary fastening pin can, possibly, be positioned in an complementary lug.The screw2is then engaged in the hole1a1of the tab1ato place the fracture in compression.Once the compression has been done, the surgeon can screw one or several other additional fastening screws3and remove the temporary pin.

In a known manner, this plate1has smooth and/or threaded holes for the fastening screws3set in the bone parts O1and O2to engage in, as shown inFIGS. 3 and 4.

Similarly, the plate1can have at least one hole1cfor a pin for temporarily positioning the plate1. Advantageously, the plate1can have a guide1cfor the insertion of a pin on the side of one of the bone parts O1and another guide1dfor the insertion of another pin on the side of the other bone part O2.

Considering the effect of the desired compression, such as indicated above, the guide1cis a circular hole whose diameter corresponds substantially to that of the pin4, whereas the other guide1dcan be an elongated slot.

These provisions thus enable the bone to slide under the plate1as the screws are set, while ensuring compression along a precise direction, generally axially or parallel to the plate. The pins are of any known and appropriate type, and perfectly known to one having ordinary skill in the art.

The plate1can have several shapes, so that the holes1ain particular can be aligned or arrayed, all or in part, according to the corners of a triangle or of a quadrilateral. These provisions, in triangle or in quadrilateral, of the screws, improve the stability of its mounting.

It must be noted also that the plate1, no matter its shape, can be longitudinally bent so as to adapt to the curvature of the bone, consequently enabling the screws2to form an angle between them.

The advantages are readily apparent from the description.