Background: The consequences of arthroscopic plication for the
treatment of anterior shoulder instability are unknown. The purpose of this
study was to evaluate the effects of arthroscopic plication on glenohumeral
translation, the rotational range of motion, and the positions of the
glenohumeral center of rotation.
Methods: Six cadaver shoulders were tested in the intact state,
after simulation of anterior instability by anterior capsular stretching,
after creation of arthroscopic portals, and following a 10-mm anteroinferior
arthroscopic suture plication. Capsulolabral build-up was measured to quantify
the increase after plication.
Results: Stretching resulted in a significant increase, compared
with the intact state, in external rotation (mean increase, 23.2° [14.3%];
p < 0.001) but not in glenohumeral translation (mean increase, 0.8 mm
[7.4%] under a 20-N translational load; p = 0.06). After plication, external
rotation decreased significantly (by 12.6° [6.7%], p = 0.003) compared
with that following the stretching. After plication, the glenohumeral center
of rotation was significantly shifted posteriorly at 60°, 90°, and
120° of external rotation and inferiorly at 90° and 120°.
Plication also resulted in significant decreases in anterior translation (mean
decrease, 61.1% under a 15-N translational load and 49.8% under a 20-N
translational load; p < 0.001), posterior translation (mean decrease, 11.4%
under a 15-N translational load and 13.1% under a 20-N translational load; p =
0.002 and p < 0.001, respectively), and inferior translation (mean
decrease, 3.2% under a 20-N load; p = 0.04). The height of the capsulolabral
"bumper" increased from 2.9 mm in the intact state to 6.4 mm
following plication (p = 0.001).
Conclusions: Arthroscopic anteroinferior plication effectively
reduces anterior translation and external rotation. Capsulolabral buildup may
help limit anterior translation without affecting rotation. Plication resulted
in a shift of the glenohumeral center of rotation posteriorly and
Clinical Relevance: Anterior translation and external rotation can
be significantly restricted by arthroscopic anteroinferior suture