Fastener, particularly suited for orthopedic use

An orthopedic fastener for joining a first body structure member to a second body structure member, comprising:

• a head portion structurally adapted for receiving a force axially applied to said orthopedic fastener to drive said fastener into one of said first and second body structure members;
• a tip portion structurally adapted for leading said fastener into one of said body structure members;
• and
• a shank portion comprising a threaded portion, said threaded portion comprising a thread-bearing zone including threads having a profile which includes a radially extending butt surface, radially extending outwardly from said shank portion of said fastener, and an outwardly flared portion, flared outwardly along a predetermined path from said shank portion to said radially extending portion, the intersection between said flared portion and said butt surface defining the major diameter of said threads in said thread-bearing zone, and a thread-free zone circumferentially spaced about said shank portion, said thread-bearing zone and said thread-free zone together comprising the entire circumference of said shank portion, each of said zones occupying a predetermined angular displacement about said shank portion of said fastener, the ratio of said thread-bearing zone to said thread-free zone being such that said shank portion is structurally adapted to be driven into either of said first and said second body structure members by the application of an axial force to said fastener and to secure said first body structure member to said second body structure member by rotating said fastener, after being so driven, through a predetermined angular displacement to secure said thread-bearing zone in at least one of said body structure members, said fastener when joining said first and second body structure members passing through at least one said first and second body structure members and into the other, and wherein said major diameter increases for a predetermined length between said tip portion and a predetermined location of maximum major diameter and gradually decreases from said predetermined location toward said head portion so that the varying diameter thus defined aids in the extraction of said orthopedic fastener.

A fastener for use in joining a first member to a second member, comprising:

• a head portion structurally adapted for receiving a force axially applied to said fastener to drive said fastener into one of said first and second members;
• a tip portion structurally adapted for leading said fastener into one of said first and second members;
• a shank portion comprising a threaded portion, said threaded portion comprising a thread-bearing zone including threads having a profile which includes a radially extending butt surface, radially extending outwardly from said shank portion of said fastener, and an outwardly flared portion, flared outwardly along a predetermined path from said shank portion to said radially extending butt surface, the intersection between said flared portion and said butt surface defining the major diameter of said threads in said threaded zone, and a thread-free zone circumferentially spaced about said shank portion, said thread-bearing zone and said thread-free zone together comprising the entire circumference of said shank portion, each of said zones occupying a predetermined angular displacement about said shank portion of said fastener, the ratio of said thread-bearing zone to said thread-free zone being such that said shank portion is structurally adapted to be driven into either of said first and said second members by the application of an axial force to said fastener and to secure said first member to said second member by rotating said fastener, after being so driven, through a predetermined angular displacement to secure said thread-bearing zone in at least one of said members, and wherein said major diameter increases for a predetermined length between said tip portion and a predetermined location of maximum major diameter and gradually decreases from said predetermined location toward said head portion so that the varying diameter thus defined aids in the extraction of said fastener, and wherein said radially extending butt surfaces of said thread profile on the lower portion of said fastener between said predetermined location and said tip are located on the side of said thread profile facing said head portion, while said butt surfaces of said thread profile between said predetermined location and said thread profile between said predetermined location and said head portion are on the side of said thread profile facing said tip.