Abstract
Purpose This study aimed to assess the biomechanical stability of a novel internal fixation system of EndoButton plate combined with suture anchor in treating acromioclavicular joint dislocation in the cadaveric specimens. In addition, it provides a new method for the clinical treatment of acromioclavicular joint dislocation. Methods Twelve complete shoulder joint specimens were randomly divided into groups A, B, C, and D (n = 3). Firstly, a quasi-static non-destructive circulation experiment was carried out of coracoclavicular ligament until its function failed. Four different internal fixation materials were used to reduce and fix the acromioclavicular joint. Group A was treated with 3.5 mm clavicular hook locking compression plates, Group B with 5 mm suture anchor Group C with 10 mm Endo-button plate, and Group D with a novel combination of 5 mm suture anchor and 10 mm Endo-button plate. Fluoroscopy was performed to undertake the X-ray of the restored acromioclavicular joint, to evaluate the internal fixation position and acromioclavicular joint reduction. Finally, the shoulder joint was fixed firmly on an electronic universal testing machine (100KN) with a self-made stationary fixture, to conduct a destructive static tensile mechanical test of each specimen vertically at a 100 mm/min load speed. The stress-deformation curve was recorded using a computer connected with the universal mechanical testing machine, and the failure strength and reasons for internal fixation were also recorded. Results The average load-to-failure of the coracoclavicular ligament in groups A, B, C, and D was 373.4 ±0.57 N, 373.6 ±0.62 N, 374.4 ±0.68 N, and 373.9 ±0.15 N, respectively (P>0.05). After internal fixation failure, Group A showed two specimens with clavicular fracture, and one with acromial fracture, with an average load-to-failure of 409.8 ±2.92 N. Group B and D showed three specimens with prolapse of anchor, with average load-to-failure of 293.5 ±4.10 N and 374.2 ±0.40 N, respectively. Group C showed three specimens with basilar coracoid fracture, with average load-to-failure of 373.2 ±2.35 N. Statistical differences existed in the biomechanical load of internal fixation failure among the four groups. Group D was statistically different from Group A and Group B, but not Group C. Conclusion The newly designed EndoButton plate combined with suture anchor for coracoclavicular ligament reconstruction was found to boast simple operation and has high feasibility. Thus it was found effective in the reduction of acromioclavicular joint and treatment of acromioclavicular joint dislocation and fitted the biomechanical characteristics of the acromioclavicular joint.
Hook plate fixation with and without coracoclavicular ligament augmentation with suture anchors for acute acromioclavicular joint dislocation
