Anatomical and radiological study of coracoclavicular ligament reconstruction

Abstract

Background Occurring in almost all age groups, acromioclavicular joint dislocation is a common type of injury in orthopedics with 15-45 years old as the age range with the highest incidence.The core pathological change of acromioclavicular joint dislocation is a rupture ofcoracoclavicular ligament, which in turn causes the instability of acromioclavicular joint and the displacement of distal clavicle relative to acromion.Consequently, a series of clinical symptom is resulted.Clavicular hook plate fixation was used to be applied in the treatment of acromioclavicular joint dislocation. However, there are complications such as the stress fractures of hook plate, the wear of acromion and the loss of reduction after plate removal. Currently, minimally invasive arthroscopyassisted Endobutton fixation has become the prior choice for the treatment of this disease.The key of the procedure is thein-depth understandingofthe anatomy and imaging of trapezoid ligament and conoid ligament. Objective To measure the radiological parameters of coracoclavicular ligament bone tunnel under different fluoroscopic positions in order to provide the anatomic basis for clinical coracoclavicular ligament reconstruction. Methods Twenty-two cadaver specimens of shoulder jointwere used to measure the direction, width of footprint and angle under perspective position of two parts of the coracoclavicular ligament (trapezoid ligamentand conoid ligament) . Results The widths of trapezoid ligament footprint were (26.2±1.2) mm on the clavicle side and (22.7±1.6) mm on the coracoid side.The widths of conoid ligament footprintwere (24.6±1.4) mm on the clavicle side and (19.2±1.6) mm on the coracoid side.Radiological measurementof ligament angulation: the angle between trapezoid ligament and the longitudinal axis of clavicle was (81±4) ° on the anteroposterior view of scapula. Lateral argumentation (83±3) °for trapezoid ligamentand (70±6) ° for conoid ligament. Adjacent relationship with surgical marker: the distances between trapezoid ligament and the midpoint of long axis conoid ligament footprint were (21.9±4.8) mm on the clavicle side and (15.7±1.6) mm on the coracoid side. Conclusion The widths of trapezoid ligament and conoid ligamentfootprints are relatively constant. The angle of trapezoid ligamentinsertion is variable, while the angle of conoid ligament insertion is relatively constant. The anatomic characteristics of coracoclavicularligament can be taken for reference during the anatomic reconstruction of acromioclavicular joint. Key words: Coracoclavicular joint; Trapezoid ligament; Conoid ligament; Reconstruction