Multicenter, longitudinal study of acromioclavicular joint reconstruction techniques for restoring shoulder complex biomechanics and soft tissue health

PROJECT SUMMARY: Acromioclavicular joint (ACJ) injuries are one of the most prevalent shoulder injuries among young athletes participating in contact sports, which could have long-term impacts on shoulder health and function. ACJ reconstruction surgery is generally recommended for patients with high-grade injuries. Currently, there is limited

evidence supporting the selection of the optimal surgical technique for these patients. Surgical techniques in this context can be categorized as rigid and non-rigid fixations. Rigid fixations are falling out of favor with sports medicine doctors due to their inferior outcomes. Therefore, modern ACJ surgical repairs primarily focus on non-

rigid fixations, which can mimic the native anatomy and function of the disrupted joint better. Within non-rigid anatomical fixation, two sub-categories can be identified. The first, more conventional sub-category is to reconstruct only the vertical stabilizers of the ACJ (i.e., coracoclavicular ligaments). Lately, reconstructing the

ACJ capsule and the AC ligaments has received increased attention due to their distinct role in the horizontal stability of ACJ, which is critical to surgical success and better patient outcomes. So, the second sub-category emerged that combines acromioclavicular and coracoclavicular reconstruction to stabilize the joint more

completely. However, the benefits of this more complex procedure on shoulder mechanics and soft-tissue health have yet to be determined (Gap 1). Also, within the combined technique, controversy exists on whether to perform these repairs using suture techniques with bone tunnels (known to increase clavicle/coracoid fracture

risk) or to employ tunnel-free techniques that reduce the complication risks but may be less effective in restoring shoulder stability and range of motion (Gap 2). We address these gaps by a multi-center longitudinal study and test three groups of ACJ reconstructed patients receiving one of the following surgeries: 1) coracoclavicular reconstruction alone with bone tunnels, 2)

combined coracoclavicular and acromioclavicular reconstruction with, and 3) without bone tunnels. We will use advanced Dynamic Stereo X-ray and cutting-edge Ultrashort Echo Time Magnetic Resonance Imaging to compare shoulder mechanics and soft-tissue health between cohorts over time. Our central hypothesis is that

shoulder mechanics and soft-tissue health are better restored with the combined acromioclavicular and coracoclavicular reconstruction. Also, a less invasive tunnel-free combined reconstruction technique provides similar outcomes to that with bone tunnels. This research contributes significantly to the following areas: 1) the

effectiveness of critical surgical decisions to reconstruct ACJ will be rigorously examined on shoulder mechanics and soft tissue health over time to identify the gold-standard treatment. Specifically, we will corroborate: a) whether to concurrently reconstruct acromioclavicular and coracoclavicular structures and b) whether to use the

tunnel-free instead of bone tunnel technique. 2) to identify shortcomings that can be addressed with future developments, which can vertically advance the treatment of this frequent, potentially debilitating injury.