• Clinics in Shoulder and Elbow
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• v.18 no.3
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• pp.152-158
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• 2015

Background: Acromioclavicular (AC) stability is maintained through a complex combination of soft-tissue restraints that include coracoclavicular (CC), AC ligament and overlying muscles. Among these structures, the role of the CC ligament has continued to be studied because of its importance on shoulder kinematics, especially after AC injury. This study was designed to determine the geometric change of conoid and trapezoid ligaments and resulting stresses on these ligaments according to various scapular motions. Methods: The scapuloclavicular (SC) complex was isolated from a fresh-frozen cadaver by removing all soft tissues except the AC and CC ligaments. The anatomically aligned SC complex was then scanned with a high-resolution computed tomography scanner into 0.6- mm slices. The Finite element model of the SC complex was obtained and used for calculating the stress on different parts of the CC ligaments with simulated movements of the scapula. Results: Average stress on the conoid ligament during anterior tilt, internal rotation, and scapular protraction was higher, whereas the stress on the trapezoid ligament was more prominent during posterior tilt, external rotation, and retraction. Conclusions: We conclude that CC ligament plays an integral role in regulating horizontal SC motion as well as complex motions indicated by increased stress over the ligament with an incremental scapular position change. The conoid ligament is the key structure restraining scapular protraction that might occur in high-grade AC dislocation. Hence in CC ligament reconstructions involving only single bundle, every attempt must be made to reconstruct conoid part of CC ligament as anatomically as possible.

• Clinics in Shoulder and Elbow
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• v.13 no.1
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• pp.34-39
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• 2010

Purpose: The purpose of this study was to present methods and results for the modified Phemister operation, with a suture anchor added for augmentation of the conoid ligament in cases of acute dislocation of the acromioclavicular joint. Materials and Methods: We evaluated 14 cases of acute dislocation of the acromioclavicular joint. This included 11 cases of Rockwood type 3, and 3 cases of type 5. The mean age of patients was 45.2 years. We operated on them using an anchor for augmentation of the conoid ligament in the modified Phemister operation. The average follow-up period was 14 months and post-operative clinical analysis was conducted using the Weitzman classification, VAS Score, Constant Score and KSS Score. Results: According to Weitzman scores, 13 cases were evaluated as excellent, and one case was good. They had mean joint ranges of forward elevation of $170.7^{\circ}$, lateral elevation of 166.4, external rotation of 68.2, and internal rotation to the level of T7. The mean VAS Score was 1.9, mean Constant Score 90.8, and the mean KSS Score 91. Radiologic analysis indicated that all cases had a good result. Conclusion: The modified Phemister operation with a suture anchor added for augmentation of the conoid ligament is very effective clinically in acute dislocations of the acromioclavicular joint.