Biomechanical comparison of double versus triple button reconstruction techniques in patients with acromioclavicular joint dislocation.

BACKGROUND: Although many techniques are used to treat the acromioclavicular (AC) joint dislocations, minimal invasive or arthroscopic coracoclavicular ligament reconstructions became popular recently. In this study, authors compared the biomechanical results of double versus triple button reconstruction techniques. METHODS: Three-dimensional solid modeling of the shoulder girdle was carried out using virtual finite element modeling. AC joint dislocation was applied to the reference model, and these models were repaired by double and triple button techniques, respectively. Maximum equivalent stresses on buttons and sutures as well as displacements and reaction forces on AC joint were evaluated. RESULTS: Triple button model was more stable during flexion and abduction when compared with double button technique. CONCLUSION: Mimicking conoid ligament has a crucial mission more particularly against resistance during frontal plane actions, but the absence of the trapezoid ligament causes increasing the posterior displacement of the distal clavicle during the flexion of GH joint.