| 摘要 |
<p>The invention relates to a bioresorbable self-tapping cannulated screw made of a composite material of the polymer-ceramics type, i.e. poly-L-lactic acid and tricalcium beta-phosphate, for the fixation of soft tendinous tissues or bone-tendon-bone grafts during joint reconstruction surgery. According to the invention, the screw () comprises, at its distal end which represents the screw tip, a cone-shaped zone () provided with a double-pitch thread with three self-tapping channels () of constant depth, stretching all along the said zone. At the proximal end, the screw has a cylindrical shape () of a length which is equal with two thirds of its total length, provided with a double thread having a constant pitch allover its length, continued up to 1 mm from the proximal end (), so that the screw can be completely inserted into the bone. In the truncated cone-shaped part of the screw, the thread () is more aggressive in order to easily penetrate the cortical bone, while, in the cylindrical part, the thread () has a larger leading angle in order to prevent the graft damage. The screw is cannulated, having inside a hexagonal channel whose size is variable along the screw length.</p> |
