Weaver-Dunn

Objective:
The purpose of this study was to
evaluate the ability of the
Weaver-Dunn reconstruction of the
Acromioclavicular (AC) joint to
recreate normal passive AC joint
motion.

Methods:
Four intact hemi-torsos were used
in this study to provide a complete
shoulder girdle and musculature.
Both shoulders of each specimen
were tested. 2.0 mm k-wires were
inserted into the mid-clavicle,
biceps insertion of the humerus,
and scapular spine. Electromagnetic
motion sensors (Polhemus Inc., VT,
USA) were rigidly attached to these
pins and the sternum. The relative
position of the sensors were
recorded while the humerus was
passively moved through three cycles
of scapular plane abduction. This
motion testing protocol was
performed on the specimen in three
states: intact, after AC ligament
transection, conoid and trapezoid
ligament transection, and following a
Weaver-Dunn reconstruction. The
maximum, minimum, and total range
of translations of the clavicle with
respect to the scapula in all planes
(medial-lateral, anterior-posterior,
and inferior-superior) were analyzed
and compared across test states.
Statistical analysis was performed
using a paired Student's T-test with
0.05 being considered as significant.

Results:
The range of motion of the AC joint
in the cut state was significantly
greater than both the intact and
reconstructed states in all planes,
except anterior-posterior translation
(Table I). The maximum and
minimum points of the reconstructed
state were significantly less (max 3.5
mm, and mm. 3.3 mm) than the intact
state. All other maximum and
minimum differences were not found
to be significantly different.

Conclusions:
The Weaver-Dunn reconstruction
was found to restore the normal
range of passive motion of the AC
joint, but created a more inferior
location of the clavicle with respect
to the medial aspect of the acromion.