Biomechanics of a new technique for minimal-invasive coracoclavicular ligament reconstruction.

Abstract

PURPOSE: To evaluate the biomechanical properties of a new coracoclavicular (CC) ligament reconstruction using a subcoracoidal flip button and a tendon graft compared to an augmented tendon loop and a synthetic coracoclavicular ligament reconstruction. METHODS: A porcine metatarsalia model was used to assess supero-inferior fixation strength of (1) a new technique using an augmented tendon graft and a subcoracoidal flip button in a lifting block fashion, (2) an augmented tendon loop around the coracoid base and (3) a synthetic coracoclavicular ligament augmentation technique. Cyclic loading from 20 to 70&#xa0;N for 1,000 cycles was performed, followed by a load-to-failure protocol. RESULTS: All specimens of the three different groups survived the cyclic loading protocol. The maximum loads to failure under superior loading conditions were 760&#xa0;&#xb1;&#xa0;78&#xa0;N for group 1, 702&#xa0;&#xb1;&#xa0;48&#xa0;N for group 2 and 1117&#xa0;&#xb1;&#xa0;91&#xa0;N for group 3. The synthetic coracoclavicular ligament augmentation technique revealed significantly higher maximum loads compared to the other groups (p&#xa0;<&#xa0;0.001). The augmented tendon graft/flip button construct had higher maximum loads than the augmented tendon loop (n.s.). No significant differences were found for stiffness and elongation behaviour among the 3 tested groups. CONCLUSION: The results suggest that the described technique is an alternative option to reconstruct the CC ligaments in AC joint instability in a minimal-invasive technique. Under superior loading conditions, the biomechanical properties exhibited by this novel technique were comparable to those of the tendon loop around the coracoid base.