Orthopedic fastener

摘要

An orthopedic fastener has a head and a shank. The shank has a leading end portion adjacent a distal tip and a trailing end portion adjacent a head. An intermediate portion is positioned between the leading and trailing end portions. At the intermediate portion, the shank increases in diameter. The leading end portion has a first thread which includes one or more self-tapping cutting grooves extending adjacent the distal tip and through a plurality of the first threads. The intermediate portion has second threads extending toward the head from the leading end portion. The second threads of the intermediate portion are larger in outer diameter than the first threads in the leading end portion. The intermediate portion has one or more cutting grooves traversing at each of a leading transition at the leading end portion and at a trailing transition.

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 step up diameter transition at the leading end portion and a second trailing transition at the trailing end portion, starting at the first step up diameter transition at the leading end portion of 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 step up diameter transition, the intermediate portion has a second thread extending from the first leading transition through the second trailing transition, and the intermediate portion has the 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 but of the same pitch as the first threads in the leading end portion, the first leading step up diameter transition having one or more self-tapping cutting grooves extending from at least a first thread in the first leading step up diameter transition through at least one of said second threads to initiate tapping of the larger second threads into cortical bone, the trailing end 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 one of said second threads in the second trailing transition through at least one of the third threads to initiate tapping of the second and third threads into cortical bone and wherein the one or more cutting grooves in combination with the second and third threads form threads in the bone to hold the fastener, wherein the second threads are of a same outer diameter as the third threads in the trailing end portion, the combination of the second threads and third threads intertwined in the trailing end portion being the same size to facilitate entry of the screw into the bone.