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.] Suture anchors, also called bone or tissue anchors, provide orthopedic surgeons a mechanism for secure fixation of soft tissues to bone. A human system (TwinFix[superscript TM]) has been validated for clinical use by both in vitro and in vivo testing, and is considered to have acceptable strength to allow for appropriate healing in common indications. Therefore, implants determined to be as strong as or stronger than the TwinFix system in this model are likely to be of adequate strength to facilitate desired healing for similar applications in small animal surgery. The objectives of this study were to evaluate 6 soft tissue 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 both the proximal and distal metaphyseal bone: 3.5 mm cortical screw (10 mm), 4.0 mm cancellous screw (10 mm), BoneBiter[superscript TM] #5, IMEXTM 4.0 mm (6 mm), IMEXTM 4.7 mm (6 mm), and TwinFix[superscript TM] Ti 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.