Biomechanical comparison of the modified Bristow procedure with and without capsular repair

The Bristow procedure has become an effective surgical option for recurrent anterior instability of the shoulder; however, there is no consensus on whether a capsule repair following a Bristow procedure is necessary to restore glenohumeral stability. The purpose of this study was to evaluate whether capsular repair with a modified Bristow procedure affects rotational range of motion and glenohumeral stability.

Rotational range of motion, glenohumeral translation and kinematics were measured in eight cadaveric shoulders in 90° shoulder abduction in the scapular and coronal planes for four conditions: intact, 20 % bony Bankart lesion, modified Bristow without capsular repair and modified Bristow with capsular repair.

Creation of the bony Bankart led to a significant increase in total range of motion and anterior-inferior translation compared to the intact shoulder. The modified Bristow procedure significantly decreased anterior-inferior translation compared to the bony Bankart but did not decrease total range of motion. Capsular repair decreased total range of motion in the scapular and coronal planes and altered normal glenohumeral kinematics in external rotation positions.

Repairing the capsule in a Bristow procedure decreases rotational range of motion yet does not offer any added anterior-inferior translational stability. Capsular repair also significantly alters normal glenohumeral kinematics. Capsule repair with a Bristow procedure may not add additional glenohumeral stability in positions of apprehension and may potentially over constrain the joint and cause altered kinematics.