BACKGROUND: The clinical experience of the treatment of the sternoclavicular joint dislocation and peripheral fracture is relatively lacking, but its incidence is increasing yearly. At present, there are few studies on the anatomy and biomechanics of the sternoclavicular joint in and outside China, and no systematic anatomical measurements of the sternoclavicular joint are reported.
OBJECTIVE: To provide a biological reference for the clinical diagnosis and treatment of sternoclavicular joint dislocation or peripheral fractures by studying the anatomy and biomechanics of the sternoclavicular joint.
METHODS: (1) A total of 16 specimens (32 sides) of adult antiseptic and moist cadaveric specimens were selected. The complete manubrium, bilateral clavicle and surrounding tissues of sternoclavicular joint were anatomically separated, and repair to bone-ligament-bone specimen models. (2) The areas of manubrium articular surface and the medial clavicular articular surface of all specimens were measured by the ink pattern combined with grid counting method. (3) The morphological features of the anterior and posterior sternoclavicular ligaments of the specimens in this group were observed, and the length, width and thickness were measured and analyzed statistically. (4) The left and right sternoclavicular joints of each specimen were randomly paired into A and B groups. Group A received simply cutting of anterior sternoclavicular ligament. Group B received simply cutting of posterior sternoclavicular ligament. Before and after cuting off the ligament, the anterior and posterior load experiments were performed on the anatomical sites with the same force arm length and perpendicular to the distal clavicle. The angles of joints and load-angle regression line slopes were compared between the two groups in the anterior and posterior directions load.
RESULTS AND CONCLUSION: (1) The area of articular surface of manubrium (239.00±28.78 mm
2) was smaller than the area of medial articular surface of the clavicle (482.56±44.89 mm
2), and the difference was statistically significant (
t=-40.105,
P < 0.001). (2) The length, width and thickness of the anterior sternoclavicular ligament were (17.56±1.94 mm), (15.54±1.42 mm) and (1.93±0.32 mm), and the length, width and thickness of the posterior sternoclavicular ligament were (17.21±1.86 mm), (15.97±1.17 mm), and (2.07±0.29 mm) respectively; there was no significantly statistical difference in the length, width and thickness between them (
P > 0.05). (3) Before cutting the ligaments, when the loads were 2, 4, 6, 8, and 10 N, the angle backwards of joint caused by loads in the forward direction was less than the angle of forwards of joints caused by loads in the backward direction, but only when the loads were 6, 8, and 10 N, the difference between them was statistically significant (
P < 0.05). The slope of the regression line of load-angle for the loads in the forward direction was less than the slope of the regression line of load-angle for the loads in the backward direction, with statistical difference (
F=31.413,
P < 0.001). After the ligaments were cut, when the loads were 2, 4, 6, 8 and 10 N in the forward direction in group A and group B, the backward angulation of joint in group A was less than that in group B (
P < 0.05). The slope of the load-angled regression line in group A was less than that in group B (
F=52.224,
P < 0.001). When the loads in the backward direction in group A and group B were 2, 4, 6, 8 and 10 N, the forward angulation of joint in group A was greater than that in group B (
P < 0.05), and the slope of the load-angled regression line in group A was greater than that in group B (
F=12.503,
P=0.008). (4) These results suggest that contact area between the articular surface of the medial clavicle and the articular surface of the manubrium is narrow, which determines the instability of the joint itself. The sternoclavicular ligament is extremely important for maintaining the joint stability. The forward angulation of joint restriction effect of sternoclavicular ligament was weaker than that of the backward angulation, also because of the joint in the anatomical position of the natural forward angulation, so the sternoclavicular joint was prone to anterior dislocation. It is necessary to pay attention to the repair and reconstruction of sternoclavicular ligament when sternoclavicular joint dislocation or peripheral fractures are treated by operations.
中国组织工程研究杂志出版内容重点:人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程