In vitro evaluation of veterinary and human suture anchors in metaphyseal bone of the canine tibia

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The objectives of this study were to evaluate 6 soft tissue, orthopedic fixation devices with respect to 1) load to failure, 2) mode of failure, and 3) ease of insertion. Canine cadaveric tibias were harvested for this experimental laboratory biomechanical study. Five of each of the following fixation devices were evaluated in bone: 3.5 mm cortical screw, 4.0 mm cancellous screw, BoneBiter #5, IMEX 4.0 mm, IMEX 4.7 mm, and TwinFix 5.0 mm suture anchors. Tensile load was applied by an Instron 8821 biomechanical testing machine parallel to the axis of anchor insertion at a rate of 12.5 mm/second until failure occurred. BoneBiter was the most difficult anchor to insert successfully. Mean ± SD loads to failure were: cancellous screw (711 ± 193 N), IMEX 4.7 mm - 18g wire (661 ± 163 N), IMEX 4.0 mm -18g wire (661 ± 165 N), cortical screw (635 ± 184 N), BoneBiter #5 - Kevlar suture (393 ± 109 N), and TwinFix 5.0 mm - #2 polyester (267 ± 73 N). No significant differences were noted among the cortical screw, cancellous screw, IMEX 4.7 mm and 4.0 mm, all of which were significantly (p < .001) greater than BoneBiter and TwinFix. Failure modes were pullout of bone, suture-wire breakage, eyelet breakage, or no failure to 1000N: screws (18,0,0,2), IMEX (18,1,1,0), BoneBiter (2,8,0,0), and TwinFix (0,10,0,0).