Traumatic disruption of the acromioclavicular joint capsule is associated with pain and instability after the injury and may lead to degenerative joint disease. The objective of this study was to quantify the effect of transection of the acromioclavicular joint capsule on the kinematics and the in situ forces in the coracoclavicular ligaments in response to external loading conditions.
11 fresh-frozen human cadaveric shoulders were tested with use of a robotic/universal force-moment sensor testing system. The shoulders were subjected to 3 loading conditions (an anterior, posterior, and superior load of 70 N) in their intact state and after transection of the acromioclavicular joint capsule.
The large differences in the change of force in the conoid and trapezoid ligaments suggest that these ligaments should not be considered as one structure when surgical treatment is considered. Furthermore, transection of the capsule resulted in a shift of load to the coracoclavicular ligaments, which may render the intact coracoclavicular ligaments more likely to fail with anterior or posterior loading. The results of the present study also suggest that the intact coracoclavicular ligaments cannot compensate for the loss of capsular function during anterior-posterior loading as occurs in type-II acromioclavicular joint injuries.
Copyright remains with the authors and publisher.
Traumatic disruption of the acromioclavicular joint capsule is associated with pain and instability after the injury and may lead to degenerative joint disease. The objective of this study was to quantify the effect of transection of the acromioclavicular joint capsule on the kinematics and the in situ forces in the coracoclavicular ligaments in response to external loading conditions.
11 fresh-frozen human cadaveric shoulders were tested with use of a robotic/universal force-moment sensor testing system. The shoulders were subjected to 3 loading conditions (an anterior, posterior, and superior load of 70 N) in their intact state and after transection of the acromioclavicular joint capsule.
The large differences in the change of force in the conoid and trapezoid ligaments suggest that these ligaments should not be considered as one structure when surgical treatment is considered. Furthermore, transection of the capsule resulted in a shift of load to the coracoclavicular ligaments, which may render the intact coracoclavicular ligaments more likely to fail with anterior or posterior loading. The results of the present study also suggest that the intact coracoclavicular ligaments cannot compensate for the loss of capsular function during anterior-posterior loading as occurs in type-II acromioclavicular joint injuries.
Copyright remains with the authors and publisher.