title: Can the carbon fiber rods for the Hoffmann II external fixation system be reused?
abstract: The Hoffman II External Fixator is the external fixation system used by the United States Army during Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF). To our knowledge, there have been no studies comparing the bending strength or stiffness of new to used or reprocessed rods. The purpose of our study was to determine if there was any difference in bending strength or stiffness of these rods.  Used rods were obtained from soldiers serving in OIF/OEF. The bending strength and stiffness of these rods was determined using 4-point bending. The location of rod failure was noted. Testing conditions simulated those utilized by the manufacturer for release of new rods.  There was no statistically significant difference in bending strength. There was a 6% difference in bending stiffness between new and used rods. Thirteen total used/refurbished rods broke at locations of previous clamping, the remainder breaking at one of the loading points on the testing jig.   The difference in bending stiffness among new, reprocessed, and used rods was only 6%. The clinical significance of this is unknown. There was no difference amongst the groups in bending strength.  Rods recovered from soldiers serving in OIF/OEF appear to be safe for reuse.
authors: Carl R. Darnall Army Medical Center, Fort Hood, TX, USA. justin.robbins@amedd.army.mil
authors: Justin
authors: J
authors: Robbins
authors: Tad L
authors: TL
authors: Gerlinger
authors: John A
authors: JA
authors: Ward
mesh_terms: D001672:Biocompatible Materials; D002244:Carbon; D000077482:Carbon Fiber; D016267:External Fixators / Q000592:standards*; D008422:Materials Testing; D008887:Military Medicine; D012086:Reoperation / Q000295:instrumentation; D013314:Stress, Mechanical
chemical_list: D001672:Biocompatible Materials; D000077482:Carbon Fiber; D002244:Carbon