Acromioclavicular dislocation is one of the common clinical injuries, accounting for about 9% of shoulder injuries, and about 9.2 out of 1 000 people occur acromioclavicular dislocation every year. There are many surgical options for acromioclavicular dislocation, including Kirschner wire, tension band, hook plate, etc. However, according to the anatomical characteristics of the acromioclavicular joint, the main structures to maintain its stability are the acromioclavicular ligament and the coracoclavicular ligament, which also includes the trapezoid ligament and the conical ligament. Therefore, reconstruction of the coracoclavicular ligament at the anatomical position has the advantage of biomechanics. Its strength is closer to that of the coracoclavicular ligament itself, which has gradually become a new method for the clinical treatment of acromioclavicular dislocation. Patients with coracoclavicular ligament reconstruction at non-anatomic locations were found to have tunnel enlargement during follow-up. Tunnel enlargement can increase the risk of coracoid process or clavicle fracture, further leading to loss of reduction and redislocation after surgery, which rarely attracts doctors' attention in clinical practice. Therefore, to improve surgical skills, reduce postoperative complications, and relieve patients' pain and economic burden, it is of certain importance to study the coracoclavicular ligament anatomy.

To explore the feasibility and clinical significance of magnetic resonance imaging (MRI) imaging in measuring coracoclavicular ligament anatomical data.

From June 2020 to May 2021, 54 patients (36 males and 18 females) with a mean age was 39.76 years underwent shoulder joint MRI. The PACS software was used to measure the coracoclavicular ligament data, and the SPSS23 was used to analyze and compare the data between males and females. All patients were divided into three groups according to ages: 18-44 years old group, 45-59 years old group, and≥60 years old group, and the data differences were compared between groups. Pearson correlation analysis was used to calculate the relationship between the coracoclavicular ligament lengths, widths, distances to the distal clavicle, and the body heights and weights.

The length and width of the trapezoid ligament were (17.23±2.74) mm and (4.72±1.24) mm. The length and width of the conoid ligament were (11.80±2.69) mm and (6.14±1.76) mm. The length of the acromioclavicular ligament of the upper bunch was (15.13±3.36) mm, and the length of the acromioclavicular ligament of the lower bunch was (7.63±2.45) mm. The distance from the trapezoid ligament to the lateral end of the clavicle was (19.31±3.14) mm, and the distance from the conoid ligament to the lateral end of the clavicle was (37.40±3.81) mm. The angle between the trapezoid ligament and horizontal plane was (41.58±13.28) °, and the angle between the trapezoid ligament and sagittal plane was (48.42±13.28) °. The angle between the conoid ligament and horizontal plane was (63.30±15.92) °, and the angle between the conoid ligament and sagittal plane was (26.71±15.92) °. The angle between the trapezoid ligament and the conoid ligament was (69.21±18.04) °. Among men, the length and width of the trapezoid ligament were (17.49±2.92) mm and (4.94±1.27) mm, and the length and width of the conoid ligament were (12.14±2.94) mm and (6.22±1.78) mm. The length of the acromioclavicular ligament of the upper bunch was (15.44±3.56) mm, and the length of the acromioclavicular ligament of the lower bunch was (7.61±2.49) mm. The distance from the trapezoid ligament to the lateral end of the clavicle was (19.73±3.10) mm, and the distance from the conoid ligament to the lateral end of the clavicle was (38.54±4.06) mm. The angle between the trapezoid ligament and horizontal plane was (42.49±15.05) °, and the angle between the trapezoid ligament and sagittal plane was (47.51±15.05) °. The angle between the conoid ligament and horizontal plane was (61.24±13.67) °, and the angle between the conoid ligament and sagittal plane was (28.76±13.67) °. The angle between the trapezoid ligament and the conoid ligament was (70.98±18.50) °. Among women, the length and width of the trapezoid ligament were (16.72±2.31) mm and (4.29±1.10) mm, and the length and width of the conoid ligament were (11.13±2.02) mm and (5.99±1.76) mm. The length of the acromioclavicular ligament of the upper bunch was (14.50±2.90) mm, and the length of the acromioclavicular ligament of the lower bunch was (7.66±2.43) mm. The distance from the trapezoid ligament to the lateral end of the clavicle was (19.58±3.42) mm, and the distance from the conoid ligament to the lateral end of the clavicle was (36.14±3.18) mm. The angle between the trapezoid ligament and horizontal plane was (39.78±8.85) °, and the angle between the trapezoid ligament and sagittal plane was (50.22±8.85) °. The angle between the conoid ligament and horizontal plane was (67.41±19.45) °, and the angle between the conoid ligament and sagittal plane was (22.59±19.45) °. The angle between the trapezoid ligament and the conoid ligament was (65.65±17.02) °. In the 18-44 years old group, the length and width of the trapezoid ligament were (17.39±2.92) mm and (4.83±1.25) mm, and the length and width of the conoid ligament were (11.93±2.88) mm and (5.95±1.62) mm. The length of the acromioclavicular ligament of the upper bunch was (14.88±3.21) mm, and the length of the acromioclavicular ligament of the lower bunch was (7.18±2.31) mm. The distance from the trapezoid ligament to the lateral end of the clavicle was (19.61±3.30) mm, and the distance from the conoid ligament to the lateral end of the clavicle was (38.07±4.04) mm. The angle between the trapezoid ligament and horizontal plane was (44.67±15.57) °, and the angle between the trapezoid ligament and sagittal plane was (45.33±15.57) °. The angle between the conoid ligament and horizontal plane was (59.07±16.06) °, and the angle between the conoid ligament and sagittal plane was (30.93±16.06) °. The angle between the trapezoid ligament and the conoid ligament was (69.82±20.31) °. In the 45-59 years old group, the length and width of the trapezoid ligament were (16.61±2.41) mm and (4.69±1.28) mm, and the length and width of the conoid ligament were (11.31±2.31) mm and (6.44±1.84) mm. The length of the acromioclavicular ligament of the upper bunch was (15.86±3.60) mm, and the length of the acromioclavicular ligament of the lower bunch was (8.18±2.69) mm. The distance from the trapezoid ligament to the lateral end of the clavicle was (19.90±3.28) mm, and the distance from the conoid ligament to the lateral end of the clavicle was (37.43±3.89) mm. The angle between the trapezoid ligament and horizontal plane was (37.86±8.87) °, and the angle between the trapezoid ligament and sagittal plane was (52.14±8.87) °. The angle between the conoid ligament and horizontal plane was (68.56±12.37) °, and the angle between the conoid ligament and sagittal plane was (21.44±12.37) °. The angle between the trapezoid ligament and the conoid ligament was (68.55±15.53) °. In the ≥60 years old group, the length and width of the trapezoid ligament were (19.61±2.11) mm and (4.13±1.14) mm, and the length and width of the conoid ligament were (13.59±3.21) mm and (5.87±2.47) mm. The length of the acromioclavicular ligament of the upper bunch was (12.87±2.05) mm, and the length of the acromioclavicular ligament of the lower bunch was (7.77±1.72) mm. The distance from the trapezoid ligament to the lateral end of the clavicle was (18.97±2.01) mm, and the distance from the conoid ligament to the lateral end of the clavicle was (37.12±4.29) mm. The angle between the trapezoid ligament and horizontal plane was (40.44±13.82) °, and the angle between the trapezoid ligament and sagittal plane was (49.56±13.82) °. The angle between the conoid ligament and horizontal plane was (63.92±26.69) °, and the angle between the conoid ligament and sagittal plane was (26.09±26.69) °. The angle between the trapezoid ligament and the conoid ligament was (68.53±18.53) °. There was a statistical difference in the distance from the conoid ligament to the lateral end of the clavicle between males and females (P<0.05) . There was a statistical difference in the trapezoid ligament length between the 45-59 years old group and the ≥60 years old group (P<0.05) . There was a statistical difference in the angle between the conoid ligament and horizontal plane between the 18-44 years old group and the 45-59 years old group (P<0.05) . There were statistical differences in the angle between the conoid ligament and sagittal plane between the 18-44 years old group and the 45-59 years old group (P<0.05) . The correlation coefficient between the body height and the distance from the conical ligament to the lateral end of the clavicle was 0.417, which was positive (P<0.05) .

The data of coracoclavicular ligament measured by MRI images provided an accurate basis for anatomic reconstruction of the coracoclavicular ligament. Preoperative MRI measurement of anatomical data of the coracoclavicular ligament on the healthy side can guide the intraoperative personalized anatomic construction of the affected side, which is innovative to some extent.