Skafoid kaynamamalar›nda tespit yöntemlerinin karfl›laflt›r›lmas›: Biyomekanik çal›flma

Objectives: The purpose of this study was to analyzethe relative biomechanical stability of three types ofinternal fixation with cancellous bone graft in a cadaver-ic, scaphoid nonunion model.Materials and methods: A scaphoid nonunion modelwas created by removing a volar wedge of bone from thewaist of the scaphoid in 18 fresh frozen human cadavers.Cancellous sawbone graft was inserted into the osteotomysite and three groups of six cadavers were randomized forinternal fixation with a pair of parallel, 0.045-inch K-wires, a Mini Acutrakscrew, or a Standard Acutrakscrew,respectively. The potted specimens were tested using anInstron Tensile Testing machine by applying force to thedistal pole of the scaphoid. The load and stiffness were cal-culated at 2-mm and 4-mm displacements. Results: Both the Mini and Standard Acutrak screwswere statistically stronger and stiffer at 2-mm displace-ment than the pair of parallel K-wires. No statisticallysignificant difference was noted between the Standardand Mini screws at 2-mm displacement. At higher loads(4-mm displacement), the Standard Acutrak screw exhib-ited significantly greater strength and stiffness than theMini Acutrakscrew. Conclusion: Due to increased strength of fixation andstiffness, and with an additional advantage of interfrag-mentary compression, the Standard Acutrak screw fol-lowed by the Mini Acutrakscrew may be a better optionthan a pair of parallel K-wires in the treatment ofscaphoid nonunions.