Cyclical loading of coracoclavicular ligament reconstructions - A comparative biomechanical study

Background: Reconstruction for injuries to the acromioclavicular joint remains controversial. Hypothesis: A coracoclavicular ligament reconstruction with a semitendinosus tendon would have superior performance to the classic coracoacromial ligament transfer with or without augmentation. Study Design: Controlled laboratory study. Methods: Five cadaveric shoulders were used to reconstruct the coracoclavicular ligaments with 3 methods: coracoacromial ligament transfer without augmentation, coracoacromial ligament transfer augmented with No. 5 Ethibond suture, and a semitendinosus tendon. Each reconstruction was cyclically loaded at 40 N to 80 N for 2500 cycles, then from 40 N to 210 N for 2500 cycles, followed by loading to failure. The number of cycles to 50% and 100% loss of acromioclavicular joint reduction were recorded. Results: During the 40 N to 80 N-loading cycle, the coracoacromial transfer without augmentation failed (15 16 cycles). The augmented coracoacromial ligament transfer and the semitendinosus reconstruction did not fail (P = .008). During the 40 N to 210 N-loading cycle, the augmented coracoacromial ligament transfer failed (207 399 cycles). The semitendinosus reconstruction survived through both loading cycles (P < .01). Conclusion: Coracoclavicular ligament reconstruction with a semitendinosus graft is a biomechanically superior construct in a cyclically loaded setting to a coracoacromial ligament transfer augmented with a No. 5 Ethibond suture. Clinical Relevance: The semitendinosus graft is a strong, biologic option for reconstruction of the coracoclavicular ligaments.