an orthopedic screw with an internal bore and mating driver has a bioabsorbable polymer component . to increase the torque tolerance of the screw and to minimize the likelihood of the driver stripping inside the bore of the screw , the screw and driver are heat treated together to shrink fit the screw onto the driver thereby increasing the driver - to - screw contact and distributing the loading force over a greater area to protect against material failure . the heat treatment involves heating the screw to an elevated temperature and holding that temperature for a period to promote stress relaxation and / or crystallization of the material .