Surgical fastener with selectively coated ridges

A screw for surgical use, comprising:

• an elongated screw body having a distal end and a proximal end and defining a root portion on its exterior surface extending between said distal and proximal ends, said screw body further defining a helical thread traversing said root portion and extending outwardly from said screw body, said thread having a crest portion with edges bounded by slope portions extending inwardly from said crest edges distal and proximal to said root portion;
• means, disposed at said proximal end, for engaging a driver to enable rotatable insertion of said screw body into a tissue of a patient;
• and
• a biocompatible coating disposed on said crest portion and at least part of said distal and proximal slope portions but not on at least part of said root portion, said coating having a selected coefficient of friction different from that of said exterior surface of said screw body to modify driver torque to be applied for insertion of said screw.