Kinematic evaluation of the modified Weaver-Dunn acromioclavicular joint reconstruction.
BACKGROUND
Few reconstructive methods to treat displaced acromioclavicular separations have been evaluated using kinematic data.


OBJECTIVE
The modified Weaver-Dunn reconstruction restores intact acromioclavicular joint motion during passive scapular plane abduction.


METHODS
Controlled laboratory study.


METHODS
Acromioclavicular joint motion was recorded during passive humeral elevation in 3 states: an intact shoulder, an "injured" state in which the acromioclavicular and coracoclavicular ligaments were transected, and finally in a reconstructed state using a modified Weaver-Dunn reconstruction. Measurements were taken with an electromagnetic motion analysis system attached to rigid pins placed in the clavicle, scapula, humerus, and sternum during passive scapular plane humeral elevation.


RESULTS
Total translatory motion of the acromioclavicular joint in the cut state was significantly greater than both the intact and reconstructed states in the medial/lateral (intact, 4.3 mm; cut, 7.9 mm; reconstructed, 2.6 mm), anterior/posterior (intact, 4.8 mm; cut, 6.1 mm; reconstructed, 4.9 mm), and superior/inferior (intact, 4.1 mm; cut, 8.0 mm; reconstructed, 4.8 mm) directions. The maximum and minimum positions of the reconstructed state were significantly more anterior and inferior than in the intact state. A significant increase in acromioclavicular axial rotation was also found between the intact and cut state.


CONCLUSIONS
The modified Weaver-Dunn reconstruction was found to restore motion of the acromioclavicular joint to near-intact values, but created a more anterior and inferior position of the clavicle with respect to the acromion.


CONCLUSIONS
These kinematic data support the modified Weaver-Dunn reconstruction as a kinematically sound procedure to treat displaced acromioclavicular joint injuries.
Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, MN 55454, USA. lapra001@umn.edu
Robert F
RF
LaPrade
Daren J
DJ
Wickum
Chad J
CJ
Griffith
Paula M
PM
Ludewig
D000173:Acromioclavicular Joint / Q000293:injuries / Q000502:physiology* / Q000601:surgery*; D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D012783:Shoulder Dislocation / Q000601:surgery*