Technical Field The present invention relates to a button-shaped plate, or miniplate, for tying suturing threads in reconstructive surgery of tendon-bone lesions, particularly for massive lesions of the shoulder rotator cuff.

Background Art It is known that massive lesions of the shoulder rotator cuff cause pain and functional limitation of the shoulder; such lesions often cause the retraction of the tendon and the separation of its end from the humerus.

The surgical procedure for this problem essentially consists in passing suturing threads through the end of the tendon, inserting into the humerus, at the tendon reinsertion region (where the tendon must anchor to the bone), by means of a large needle, the pairs of ends of each thread, making the pairs of ends exit from the outer surface of the bone (after perforating, with the needle, the external cortex of the proximal end of the humerus) and tying together the pairs of ends of all the threads.

In order to achieve effective partial or full suture of the cuff it is necessary to provide an effective initial resistance, minimize tendon-bone diastasis and maintain durable mechanical stability in order to allow natural healing of the surfaces; in practice, the pairs of ends of the threads must be pulled firmly and be tied together under tension.

The tension of the threads can cause, during the operation or thereafter, the breakage of the cortical surface, due to the fact that bone often has, in the anchoring seat, osteoporosis deriving from lack of movement.

Miniplates are known which have been devised in order to obviate this drawback and are adapted to rest against the surface of the humerus, in the region where the pairs of threads are made to exit, and are crossed by a plurality of small holes through which the pairs of threads are made to exit

and then tied together.

Such known miniplates have shortcomings due to the fact that, also because of the imperfect alignment between the exit points of the pairs of threads and the holes of the plate, said plate does not adhere perfectly to the surface of the bone while the knots are being tied; on one hand, this causes less tension of the suturing threads and therefore less tendon-bone contact; and on the other hand, it entails the possibility of friction and wear of the threads between the bone edge and the edge of the holes of the plate.

Disclosure of the Invention The aim of the present invention is to obviate the above cited shortcomings and to meet the mentioned requirements, by providing a button-shaped plate for reconstructive surgery of tendon-bone lesions, particularly for massive lesions of the shoulder rotator cuff, which remains perfectly in contact with the surface of the humerus during tying of the knots and has no surfaces which can cut the suturing threads.

Within this aim, an object of the present invention is to provide a structure which is simple, relatively easy to provide in practice, safe in use, effective in operation, and relatively low in cost.

This aim and this and other objects which will become better apparent hereinafter are achieved by the present button-shaped plate for reconstructive surgery of tendon-bone lesions, particularly for massive lesions of the shoulder rotator cuff, characterized in that it has two holes which are adapted to be crossed by pairs of suturing threads, said holes being extended, on the face designed to rest against the humerus, by respective short portions of cannulas adapted to engage in corresponding holes formed beforehand in the surface of bone.

Brief description of the Drawings Further characteristics and advantages of the invention will become better apparent from the detailed description of a preferred but not exclusive embodiment of a button-shaped plate for reconstructive surgery of tendon-

bone lesions, particularly for massive lesions of the shoulder rotator cuff, according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is a front view of a button-shaped plate for reconstructive surgery of tendon-bone lesions, particularly for massive lesions of the shoulder rotator cuff ; Figure 2 is a sectional side view, taken along the line II-II of Figure 1, of said button-shaped plate; Figure 3 is a sectional bottom view of the plate; Figure 4 is a sectional top view, taken along the line IV-IV of Figure 1; Figures 5a, 5b and 5c are views of the successive steps of the application of the plate according to the invention.

Ways to carrying out the Invention With reference to the figures, 1 generally designates a button-shaped plate for reconstructive surgery of tendon-bone lesions, particularly for massive lesions of the shoulder rotator cuff, according to the invention.

The plate 1 is rectangular, with rounded corners 2, and has two holes 3 and 4 which are designed to be crossed by pairs of suturing threads F.

The holes 3,4 on the face designed to rest against the humerus are extended by respective short portions of cannulas 5 and 6 which are designed to engage in corresponding holes P formed beforehand in the surface of the bone 0.

In order to reduce the possibility of cutting the threads, the holes of the cannulas are slightly inclined with respect to the axis of said cannulas; for the same reason, at the ends of the cannulas 5 and 6 the edges 3a, 4a of the holes 3 and 4 are conveniently rounded; the outer surface of the plate has, between the holes 3 and 4, a channel 9 having a rounded profile in order to keep the threads and the knot of the threads in a protected position.

At the centerline of the longer sides, the button-shaped plate is crossed by two small holes 7 and 8 which allow to grip it with a gripping tool.

The operation of the invention and the application method are as follows: by using a template which reproduces the relative distance of the holes, the surface of the outer cortex of the proximal end of the humerus (P of Figure 5a) is perforated beforehand; the button-shaped plate is rested against the humerus so that the cannulas are inserted in the holes P formed earlier; by using a tough curved needle, the pairs of ends of the threads F coupled to the end of the tendon are inserted in the humerus (Figure 5b) in the tendon reinsertion area, which has been freshened in order to accelerate the process for bonding the tendon to the bone; the threads are made to exit through each one of the holes of the button-shaped plate; once at least one pair of threads for each hole has passed through, the pairs of threads are subjected to traction and are tied together (Figure 5c): if required, another button- shaped plate is used and arranged in another suitable position of the surface of the humerus.

It has thus been observed that the invention achieves the proposed aim and object.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

All the details may furthermore be replaced with other technically equivalent ones.

In practice, the materials used, as well as the shapes and the dimensions, may be any according to requirements without thereby abandoning the scope of the protection of the appended claims.

The disclosures in Italian Patent Application No. BO200OA000322 from which this application claims priority are incorporated herein by reference.