Biomechanical Comparison of Knotless Anchor Repair Versus Simple Suture Repair for Type II SLAP Lesions

Abstract

The purpose of this study was to evaluate glenohumeral motion after knotless anchor repair of type II SLAP lesions versus repair with simple suture arthroscopic knot-tying techniques and to compare the initial fixation strength of the 2 repair techniques. Six matched-pair cadaveric shoulders were tested in an uninjured condition, after creation of a type II SLAP tear, and after repair with either a knotless repair with two 3.5-mm Bio-PushLock anchors (Arthrex, Naples, FL) or a simple suture repair with two 3.0-mm Bio-SutureTak anchors (Arthrex) placed anterior and posterior to the biceps tendon. Glenohumeral rotation, translation, and kinematics were measured. The SLAP repairs were then loaded to failure perpendicular to the glenoid face. Glenohumeral rotation increased after creation of a type II SLAP lesion and was restored to the intact state after both repairs. There was no significant difference in glenohumeral translation or kinematics with SLAP lesion or either repair technique. There was no significant difference between stiffness, yield load, or ultimate load of the 2 repairs. Simple suture repairs failed most commonly by knot breakage, and knotless repairs failed by suture slippage around the anchor. Knotless anchor repairs of type II SLAP lesions restore glenohumeral rotation as well as simple suture arthroscopic repair techniques without overconstraining the shoulder. In addition, the initial fixation strength of knotless anchor repairs of type II SLAP lesions is similar to that of simple suture repairs. Knotless anchor repairs of type II SLAP lesions restore capsulolabral anatomy without overconstraining the shoulder.