Biomechanical evaluation of the long head of the biceps brachii tendon fixed by three techniques: a sheep model☆

OBJECTIVE To evaluate the biomechanical properties of the fixation of the long head of the biceps brachii into the humeral bone with suture anchors, interference screw, and soft tissue suture, comparing strength, highest traction load, and types of fixation failure. METHODS Thirty fresh-frozen sheep shoulders were used, separated into three groups of ten for each technique. After fixation, the tendons were subjected to longitudinal continuous loading, obtaining load-to-failure (N) and displacement (mm). RESULTS The mean load-to-failure for suture anchors was 95 ± 35.3 N, 152.7 ± 52.7 N for interference screw, and 104.7 ± 23.54 N for soft tissue technique. There was a statistically significant difference (p < 0.05), with interference screw demonstrating higher load-to-failure than suture anchor fixation (p = 0.00307) and soft tissue (p = 0.00473). The strength of interference screw was also superior when compared with the other two methods (p = 0.0000127 and p = 0.00000295, respectively). There were no differences between suture anchors and soft tissue technique regarding load-to-failure (p = 0.9420) and strength (p = 0.141). CONCLUSION Tenodesis of the long head of the biceps brachii with interference screw was stronger than the suture anchors and soft tissue techniques. The other two techniques did not differ between themselves.