| 主权项 |
1. An orthopedic fastener comprising:
a head; a shank, the shank extending from the head to a distal tip, the shank having a leading end portion adjacent the distal tip and a trailing end portion adjacent the head and an intermediate portion positioned between the leading and trailing end portions, the intermediate portion has a pair of transitions, a first leading transition at the leading end portion and a second trailing transition at the trailing end portion, at the intermediate portion the shank increasing in diameter to a larger diameter; and wherein the leading end portion has a first thread extending adjacent the distal tip through to at least the first leading transition, the intermediate portion has a second thread extending from the first leading transition to the second trailing transition, and the intermediate portion has a second thread extending toward the head from the intermediate portion, the second thread of the intermediate portion being larger in outer diameter than the first threads in the leading end portion, the first leading transition having one or more self-tapping cutting grooves extending from at least a first thread in the first leading transition through at least one of said second threads to initiate tapping of the larger second threads into cortical bone, the third portion has a third thread extending from the second trailing transition toward the head, the third thread having one or more cutting grooves extending from at least a second thread in the second trailing transition through at least one of the third threads to initiate tapping of the third thread into cortical bone and wherein the one or more cutting grooves in combination with the threads form threads in the bone to hold the fastener, wherein the leading end portion has one or more cutting grooves adjacent the distal tip and extending from at least a first thread in the leading end portion. |
