Patent ID: 8075604

Claim:
A bone screw, comprising: a threaded shank including a distal end portion and a proximal end portion, said threaded shank defining a first threaded section extending from said distal end portion toward said proximal end portion and adapted for anchoring in cancellous bone, said threaded shank defining a second threaded section extending contiguously from said first threaded section toward said proximal end portion and adapted for engagement in cortical bone, said second threaded section comprising a finer thread pattern relative to said first threaded section, and wherein said threaded shank defines an inner thread root diameter that uniformly increases along a first portion of said first threaded section from a location adjacent said distal end portion to a mid-section of said threaded shank and uniformly increases along a second portion of said second threaded section from said mid-section to a location adjacent said proximal end portion, said first and second threaded sections extend substantially continuously and contiguously along a length of said threaded shank portion; and wherein said threaded shank includes a first threading extending from said distal end portion toward said proximal end portion and including a single helical thread pattern defining said first threaded section for anchoring in the cancellous bone, said threaded shank including a second threading cooperating with said first threading to provide a double helical thread pattern defining said second threaded section for engagement in the cortical bone, and wherein said first threading has a first thread pitch, said second threading having a second thread pitch substantially equal to said first thread pitch.