Polymer-based orthopedic screw and driver system with increased insertion torque tolerance and associated method for making and using same

• Main Authors: TENHUISEN KEVOR S, CONTILIANO JOSEPH H, YUAN J. JENNY
• Format: Patent
• Language: English
• Published: 04.05.2010
• Subjects: BANDAGES, DRESSINGS OR ABSORBENT PADS; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF,TUBULAR STRUCTURES OF THE BODY, E.G. STENTS; DIAGNOSIS; FILTERS IMPLANTABLE INTO BLOOD VESSELS; FIRST-AID KITS; FOMENTATION; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; HUMAN NECESSITIES; HYGIENE; IDENTIFICATION; MEDICAL OR VETERINARY SCIENCE; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; PROSTHESES; SURGERY; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ARTCOLLECTIONS [XRACs] AND DIGESTS; TREATMENT OR PROTECTION OF EYES OR EARS

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.