Intraosseous screw for fixing a bone fragment or a transplant to a bone and method for manufacturing such an intraosseous screw
View Patent ↗An intraosseous screw includes at least one external thread, a receiving element extending into and parallel to the external thread, and connecting members connecting the individual screw threads of the external thread. The or each external thread has capillary through-channels that pass through the screw so as to end in the receiving element. The connecting members define a plurality of through-openings. The receiving element is shaped so as to be able to receive a cylindrical bone portion once the intraosseous screw has been screwed into the bone.
1. An intraosseous screw intended for fixing a bone fragment to a bone for an osteosynthesis or a transplant for a ligament surgery, the intraosseous screw comprising:
at least one outer threading, which is formed by a plurality of threads and which extends along an external helix around a longitudinal axis;
a housing which extends inside the outer threading and generally parallel to the longitudinal axis; and
connecting members arranged in such a manner as to connect the threads together;
wherein the connecting members comprise spacers, the spacers being formed by rods and arranged in such a manner as to define a multitude of through openings which open into the housing,
and wherein the housing delimits a hollow cylindrical volume which opens into at least one end of the outer threading, the hollow cylindrical volume being shaped in such a manner as to house, after screwing of the intraosseous screw into the bone, a cylindrical portion of bone.
2. The intraosseous screw according to claim 1 , wherein transverse dimensions of the housing are greater than 90% of a minimum dimension of an inner part of the outer threading.
3. The intraosseous screw according to claim 1 , wherein the hollow cylindrical volume opens at two opposed ends of the outer threading, in such a manner that, after screwing the intraosseous screw into the bone, the outer threading can house a portion of bone remaining secured to the bone.
4. The intraosseous screw according to claim 2 , wherein the hollow cylindrical volume of the housing has a diameter substantially equal to an inner diameter of the at least one end of the outer threading.
5. The intraosseous screw according to claim 1 , wherein the spacers intersect at least in pairs.
6. The intraosseous screw according to claim 5 , wherein the spacers comprise:
opposite spacers which generally extend along opposite helices which are oriented inversely to the external helix of said at least one outer threading; and
direct spacers which generally extend along direct helices which are oriented like the external helix of said at least one outer threading.
7. The intraosseous screw according to claim 1 , wherein said at least one outer threading has several capillary channels which cross said at least one outer threading in such a manner as to open into the housing.
8. The intraosseous screw according to claim 1 , wherein at least some of the spacers have through capillary channels in such a manner as to open into the housing.
9. The intraosseous screw according to claim 7 , wherein at least some elements from among said capillary channels and said through openings have shapes converging from an outer surface of the outer threading towards the housing and diverging from an outer surface of the outer threading towards the housing.
10. The intraosseous screw according to claim 1 , wherein said at least one outer threading and the connecting members are respectively composed of compressed fibers.
11. The intraosseous screw according to claim 10 , wherein the compressed fibers comprise fibers composed of lactic acid polymer (PLA).
12. The intraosseous screw according to claim 10 , wherein the compressed fibers further comprise fibers of strontium.
13. The intraosseous screw according to claim 1 , further comprising a screw head arranged in such a manner that the intraosseous screw can be tightened in a bore after previous removal of a portion of a generally cylindrical bone.
14. The intraosseous screw according to claim 1 , further comprising an inner threading which extends on the edges of the housing.
15. The intraosseous screw according to claim 1 , wherein each spacer extends between two consecutive threads.
16. The intraosseous screw according to claim 1 , wherein the spacers are configured in such a manner that the combined surface area of the through openings represents at least 50% of the surface delimited between the threads.
17. The intraosseous screw according to claim 1 , comprising at least 5 spacers, between two consecutive threads.
18. A manufacturing method, for manufacturing an intraosseous screw according to claim 1 , the manufacturing method comprising steps of projecting fibers in a mold a cavity of which defines the intraosseous screw.