A biomechanical comparison of EndoButton versus suture anchor repair of distal biceps tendon injuries

The purpose of this study was to compare suture anchor and EndoButton repair of distal biceps injuries in a human bone-tendon model. Right and left arm repairs were alternately performed with either the EndoButton or 2 single-loaded 5-mm suture anchors. Each construct was cyclically loaded by use of a servohydraulic materials testing machine. Initial and final displacements were recorded. All repairs were then loaded to ultimate failure. Ten millimeters of displacement was designated the clinical failure point. The EndoButton group had more stiffness than the suture anchor group during initial cyclic loading (P = .01). There were no differences in final displacement measured after cyclic loading (2.06 mm for suture anchors and 2.58 mm for EndoButton). The EndoButton group had a 16% greater ultimate tensile load than the suture anchor group (274.77 N vs 230.06 N). The EndoButton group also had a 16% higher load to clinical failure (249.95 N vs 209.56 N). These differences were not statistically significant. The EndoButton and suture anchors provide comparable fixation strength for the repair and rehabilitation of distal biceps tendon ruptures.