Biomechanical Evaluation of a Single- Versus Double-Tunnel Coracoclavicular Ligament Reconstruction With Acromioclavicular Stabilization for Acromioclavicular Joint Injuries

Abstract

Background: An anatomic double-tunnel (DT) reconstruction technique has been widely adopted to reconstruct the ruptured coracoclavicular (CC) ligaments seen with high-grade acromioclavicular (AC) joint injuries. However, the anatomic DT reconstruction has been associated with the risk of clavicle fractures, which may be problematic, particularly for contact athletes. Purpose/Hypothesis: The purpose was to compare a single-tunnel (ST) CC ligament reconstruction for AC joint injuries with the native state as well as with the more established anatomic DT CC ligament reconstruction. The hypothesis was that ST CC ligament reconstruction would demonstrate biomechanical properties similar to those of the native state and the DT CC ligament reconstruction. Study Design: Controlled laboratory study. Methods: Eighteen fresh-frozen human cadaveric shoulders (9 matched pairs) with mean ± SD age of 55.5 ± 8.5 years underwent biomechanical testing. One specimen of each matched pair underwent a ST CC ligament reconstruction and the second, a DT CC ligament reconstruction. The ST and DT CC ligament reconstruction techniques involved a 5-mm distal clavicle excision, avoided coracoid drilling, and utilized a 3.0-mm suture anchor to fix the excess lateral limb to reconstruct the superior AC joint capsule. The ST CC ligament reconstruction technique additionally included a 1.3-mm suture tape to help avoid a sawing effect, as well as a dog-bone button over the clavicular tunnel to increase stability of the construct. All specimens were tested to 70 N in 3 directions (superior, anterior, and posterior) in the intact and reconstructed states. The ultimate load, yield load, stiffness, and mode of failure of the reconstructed specimens were tested. Results: There were no significant differences in translation at 70 N in the superior ( P = .31), anterior ( P = .56), and posterior ( P = .35) directions between the ST CC ligament reconstruction and the intact state. The ultimate load to failure, yield load, and stiffness in the ST and DT groups were also not significantly different. There were no distal clavicle fractures in load-to-failure testing in the ST or DT group. Conclusion: In this biomechanical study, ST CC ligament reconstruction demonstrates biomechanical properties comparable to the intact state. Additionally, use of the ST CC ligament reconstruction shows biomechanical properties similar to the DT CC ligament reconstruction technique while theoretically posing less risk of clavicle fracture. Clinical Relevance: This study suggests that the ST CC ligament reconstruction has biomechanical properties equivalent to the DT CC ligament reconstruction with less theoretical risk of clavicle fracture.