The Biomechanical Experiment And Clinical Study Of Coracoclavicular Ligament Reconstruction In The Treatment Of Dislocation Of Acromioclavicular Joint

Objective Through the anatomic study of the bone and ligament structure of the acromioclavicular joint in normal cadavers and the biomechanical test,the effects of the ligaments around the acromioclavicular joint on the stability of the acromioclavicular joint were understood,providing the anatomical and biomechanical basis for the clinical treatment of acromioclavicular joint dislocation.At the same time,a variety of biomechanical studies were conducted on the choice of internal fixation for the dislocation of acromioclavicular joint,to test the biomechanical stability of the new anchor-loop internal fixation system for the treatment of acromioclavicular joint dislocation,and to provide a new method for the clinical treatment of acromioclavicular joint dislocation.Methods The distribution,appearance and attachment area of 12 acromioclavicular ligaments were observed.The length,Angle and the distance from the most lateral point to the distal end of the clavicle were measured in the coronal and sagittal positions of the clavicular attachment area of the conical and trapeziate ligaments.Subsequently,12 complete shoulder joint specimens were randomly divided into four groups of A,B,C and D,with 3 specimens in each group.Group A retained the acromioclavicular ligament;Group B retained the coracoid ligament;The trapeziate ligament was preserved in group C.Group D retained the conical ligament.Using self-made fixed clamp and tensile connection device will shoulder joint firmly fixed on a mechanical test machine,with 100 mm/min load rate on the ligament in the vertical direction were destructive static stretching mechanics,computer records in connection with the biomechanical testing machine and drawing load-displacement curve,record each ligament rupture strength.Four different internal fixation materials were used to restore and fix the acromioclavicular joint.Group A was A 3.5mm clavicular hook locking compression plate;Group B is 5mm soft tissue wire anchor;Group C is 10 mm Endobutton steel plate;Group D is a new anchor-loop steel plate(5mm soft tissue tape anchor +10mm Endobutton steel plate).Then the internal fixation position and the reduction of acromioclavicular joint were evaluated by X-ray fluoroscopy.Finally,the mechanical testing machine was used to measure the destructive static tensile mechanics of each experimental specimen in the vertical direction.The computer connected with the biomechanical testing machine was used to record and describe the load-displacement curve,and the failure strength and failure reason of each group internal fixation were recorded.Results Coracoclavicular ligament: the conical ligament starts from the inner side of the coracoid process base,and is fan-shaped upward in the coronal plane,ending at the conical nodule of the clavicle,with a length of 10.6±0.66 mm.The coronal and sagittal lengths of the clavicular attachment area were 13.4±0.35 mm and 5.8±0.18 mm.The distance from the outermost point to the distal end of the clavicle was 35.5±1.71 mm.Coronary position Angle,sagittal position Angle of 6.2±0.25 °and 11.3±1.81 °.The trapezius ligament is lateral,arising from most of the medial front of the coracoid process,passing outwards and upwards in the sagittal plane and ending at the trapezius ridge on the subclavian surface.The length is 12.5±0.44 mm.The coronal and sagittal lengths of the clavicular attachment area were 14.2±3.56 mm and 8.7±0.24 mm.The distance from the outermost point to the distal end of the clavicle was 23.6 1.86 mm.Coronal,sagittal position Angle of 38.7±0.38 °and 6.9±0.35 °.The average breaking forces of acromioclavicular ligament,coracoid clavicular ligament,trapeziate ligament and conical ligament were 201.3±1.91 N,374.6±1.15 N and 192.3±4.26 N,345.7±1.14 N,respectively.Comparing the mechanical data of the four groups,the P values were all less than 0.05.In the clavicular hook locking compression plate group,the average tension of internal fixation failure was 409.8±2.92 N.Two specimens were clavicular fractures and one was acromial fracture.The average tensile force of internal fixation failure in the soft tissue band wire anchor group was 293.5±4.10 N,and the three specimens were all anchor protrusions.The Endobutton plate group had an average internal fixation failure tension of 373.2±2.35 N,and all 3 specimens were fracture of coracoid process base.The mean tension of internal fixation failure of anchor-loop steel plate group was 374.2±0.40 N,and all 3 specimens were anchor protrusions.The biomechanical loads of internal fixation failure in the four experimental groups were statistically different.Compared between groups,the biomechanical load of internal fixation failure in group D was statistically different from that in group A and group B,but not from that in group C.Conclusion The acromioclavicular ligament(conical ligament,trapeziate ligament)and acromioclavicular ligament have different roles and contributions in maintaining the stability of acromioclavicular joint.About 65% of the stability of acromioclavicular joint is provided by acromioclavicular ligament.In anatomical reconstruction,the trapeziate ligament and the conical ligament should be treated differently.The role of conical ligament is more prominent,and the anatomical reconstruction of conical ligament is more important in the reconstruction of coracoclavicular ligament.Meanwhile,the acromioclavicular ligament should be repaired in the first stage as far as possible.The newly designed anchor loop plate can effectively reduce the acromioclavicular joint,which conforms to the biomechanical characteristics of acromioclavicular joint.With simple operation,it can effectively treat the dislocation of acromioclavicular joint and has a high feasibility.