Headed screw construction for use in fixing the position of an intramedullary nail
First Claim
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1. A headed screw with a bone-engaging screw thread, comprising an elongate shank having an external thread for bone-engaged anchorage of said screw, and a drive head at one end of said shank, wherein:
- (a) the drive head (2) has an external thread (5) having a direction of thread advance which is opposite to the direction of shank-thread advance;
(b) the shank thread is at least at the opposite end of said shank; and
(c) the maximum diameter of the shank thread is the maximum diameter of the shank.
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Abstract
The invention relates to a headed screw for fixing an intramedullary nail in position. An external thread on the screw shank is provided over all, or a part of spaced parts, of the length of the shank. The screw head is provided with an external thread having a direction of helical advance which is opposite the direction of helical advance of the screw-shank thread.
358 Citations
9 Claims
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1. A headed screw with a bone-engaging screw thread, comprising an elongate shank having an external thread for bone-engaged anchorage of said screw, and a drive head at one end of said shank, wherein:
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(a) the drive head (2) has an external thread (5) having a direction of thread advance which is opposite to the direction of shank-thread advance; (b) the shank thread is at least at the opposite end of said shank; and (c) the maximum diameter of the shank thread is the maximum diameter of the shank. - View Dependent Claims (2, 3, 5)
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4. A headed screw with a bone-engaging screw thread, comprising an elongate shank having an external thread for bone-engaged anchorage of said screw, and a drive head at one end of said shank, wherein:
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(a) the drive head (2) has an external thread (5) having a direction of thread advance which is opposite to the direction of shank-thread advance; (b) the shank thread is at least at the opposite end of said shank and is limited to only a portion of the length of said shank; and (c) a second threaded portion of said shank is additionally provided near said one end.
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6. A headed screw with a bone-engaging screw thread, comprising an elongate shank having an external thread for bone-engaged anchorage of said screw, and a drive head at one end of said shank, wherein:
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(a) the drive head (2) has an external thread (5) having a direction of thread advance which is opposite to the direction of shank-thread advance; (b) the shank thread is at least at the opposite end of said shank; (c) a portion of shank is cylindrical; and (d) the thread at the opposite end of said shank has a maximum diameter that is at least no greater than the diameter of said cylindrical portion. - View Dependent Claims (7, 8)
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9. A headed screw with a bone-engaging screw thread, comprising an elongate shank having an external thread for bone-engaged anchorage of said screw, and a drive head at one end of said shank, wherein:
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(a) the drive head (2) has an external thread (5) having a direction of thread advance which is opposite to the direction of shank-thread advance; (b) the shank thread is only at the opposite end of said shank; (c) the remainder of said shank is cylindrical, and (d) the maximum diameter of the shank thread is no greater than the diameter of said cylindrical remainder.
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Specification