Viscoelastic behavior and structural properties of the coracoclavicular ligaments

Abstract

During contact sports such as football, hockey or rugby, the coracoclavicular ligaments are commonly ruptured. Currently, the limited biomechanical data on the properties and function of these ligaments have led to debate on the "gold standard" treatment for these injuries. Therefore, the objective of this study was to characterize the geometry, viscoelastic behavior and structural properties of the coracoclavicular ligaments (n=11). The trapezoid and conoid were found to have similar length (9.6+/-4.4 vs. 11.2+/-4.1 mm) and cross-sectional area (103+/-43 vs. 69+/-51 mm2), respectively (P>0.05). Static and cyclic stress relaxation tests were then performed, followed by uniaxial tensile testing with the insertions of each ligament aligned to ensure a uniform distribution of load across the fibers. No significant differences were observed for the trapezoid and conoid during the static (36+/-8% vs. 31+/-7%) and cyclic (23+/-12% vs. 16+/-6%) stress relaxation tests, respectively (P>0.05). Similarly, no statistically significant differences were found between the trapezoid and conoid for linear stiffness (83+/-40 vs. 70+/-23 N mm(-1)), ultimate load (312+/-133 vs. 266+/- 108 N), energy absorbed at failure (820+/-576 vs. 752+/- 410 N mm), percent elongation (74+/-47% vs. 62+/-22%) and elongation at failure (5.8+/-2.2 vs. 6.1+/-1.6 mm), respectively (P>0.05). A comparison of our data to previous studies suggests that the complex fiber orientation of these ligaments has a significant role in determining the maximum load that can be transferred between the clavicle and scapula by each bone-ligament-bone complex. Our findings also further confirm the functional role of the coracoclavicular ligaments in supporting the upper extremity, and provide data for reconstruction and rehabilitation protocols as well as computational models.

Medial coracoclavicular ligament revisited: an anatomic study and review of the literature

“…The trapezoid ligament expanded to 2.15 cm at the clavicular level, a similar feature that we found at the level of MCCL attachment to coracoid process. The CCL geometry in another study gave somewhat smaller dimensions and, interestingly, no significant differences could be demonstrated between conoid and trapezoid ligament [4]. On the other hand, Ockert et al found the ligaments to be larger than in the previous two studies, precisely distinguishing the 3D components-length, width, and depth [15].…”

“…In the report of Satler et al [17] the histological sections included the plenitude of the acromioclavicular joint with the surrounding ligaments, in order to study better the anatomical relationships of the structures in question. Based on tensile testing and not on histology, no statistically significant differences could be demonstrated for all structural properties between the conoid and trapezoid ligament [4]. A comprehensive immunochemistry study, carried out on CCL complex, revealed fibrocartilage at the level of both clavicular and coracoid entheses, considering it a consequence of adaptation to compression and shear forces [15].…”

Coracoclavicular ligament reconstruction: biomechanical comparison of tendon graft repairs to a synthetic double bundle augmentation

“…We have not addressed parameters such as failure under anterior and posterior loading and rotational motion. However, the stability in the frontal plane has been evaluated to be the limiting capacity of a coracoclavicular augmentation, while the coracoclavicular ligaments serve as the main stabilizer in the superio-inferior direction [5][6][7]. The parameters studied were chosen because they seem to be most relevant to the clinical process.…”

“…The distance between the inferior cortex of the clavicle bone and the superior cortex of the coracoid bone was standardized: 10 mm in the superio-inferior direction and 6 mm in the anterio-posterior direction, resulting in spatial distance of 12 mm. These distances as well fit the physiologic dimensions [5,12,26]. All bones were stored at -20°C temperature.…”

Relative contribution of acromioclavicular joint capsule and coracoclavicular ligaments to acromioclavicular stability

“…2,[4][5][6][7][11][12][13][14]17,23 However, these anatomic and biomechanical studies were typically performed on an isolated structure and do not provide insight into the complex interplay between the AC joint capsule and CC ligaments. In addition, there are no direct comparisons of the biomechanical characteristics or relative contribution of these structures to AC joint stability.…”