Arthroscopic Suture Anchor Capsulorrhaphy Versus Suture Capsulorrhaphy in a Cadaveric Model (SS-01)

Abstract

Introduction Recurrent anterior glenohumeral instability is challenging to treat. Arthroscopic capsulorrhaphy utilizing either a solitary suture or suture anchor has proven effective in alleviating instability symptoms. To date, no study was found that determined whether suture capsulorrhaphy or suture anchor capsulorrhaphy is more effective at reducing anterior translation. Thus, the purpose of this study is to establish whether there is biomechanical benefit for the use of anchor capsulorrhaphy versus suture capsulorrhaphy in the management of anterior shoulder instability. Methods Twelve matched pairs of fresh, frozen shoulders were randomized to either anchor or suture capsulorrhaphy group. Specimens were mounted in 60-degrees of abduction and 90-degrees of external rotation in the plane of the scapula. Testing was conducted on an MTS with the use of Vicon motion capture system. Compressive load of 22N was applied to each shoulder and subsequent 2N anterior and posterior force was applied to establish zero point. Translation with 10N anterior and posterior loads was then recorded. Arthroscopic capsulorrhaphy was performed with either three solitary sutures or three suture anchors. Specimens were remounted and returned to the zero-point. A 10N anterior force, 10N posterior force, and an anterior load to failure force were applied, respectively. Translation from zero was measured. Load to failure was defined as the amount of force required to return to preoperative zero point. Specimens were loaded-to-failure at a rate of 0.1mm/sec. Data were reported in millimeters ±SEM with significance set at p Results Load-to-failure was significantly greater (p=0.02) in the anchor capsulorrhaphy group (20.5N±2.8) versus suture capsulorrhaphy group (13.6N±1.0). When comparing reduction of anterior translation with a 10N load, no differences were found between suture capsulorrhaphy (2.7mm±0.7) and anchor capsulorrhaphy (2.3mm±0.6). Percent reduction of anterior displacement with a 10N load was not different for the suture capsulorrhaphy (49.9%) versus anchor capsulorrhaphy (49.6%) groups. Tissue pull-through of the suture was the dominant mode of failure in the study. Conclusion Suture capsulorrhaphy and anchor capsulorrhaphy reduce anterior glenohumeral translation at low loading conditions. Load-to-failure studies indicate that anchor capsulorrhaphy exhibits significantly greater resistance to translation at higher loading conditions. Thus, it is concluded that the use of arthroscopic suture anchors is more effective than suture capsulorrhaphy in reducing catastrophic anterior glenohumeral translation in cadavers. Our study suggests that the use of a suture anchor when performing a capsulorrhaphy may provide biomechanical advantage at high loading conditions. Potential benefits of suture anchor capsulorrhaphy include increased resistance to glenohumeral translation and higher load to failure. This may represent better clinical outcomes and a reduction in the rate of recurrent instability as a result.