Anterior Capsulorrhaphy: An In Vitro Comparison of Volume Reduction—Arthroscopic Plication Versus Open Capsular Shift

Purpose: The purpose of this study was to objectively compare volume reduction after arthroscopic plication and open lateral capsular shift. Type of Study: Experimental cadaver study. Methods: Fifteen fresh-frozen human cadaver shoulders were assigned to 1 of 2 groups: arthroscopic plication (n = 7) or open lateral capsular shift (n = 8). Initial capsular volume was measured by repeated injection of a viscous fatty acid sulfate solution and recorded for each specimen. Repeated measurements were taken after the procedure to determine volume reduction. Results: Both procedures resulted in reduction of capsular volume. The arthroscopic plication resulted in a 22.8% volume reduction and the open lateral capsular shift resulted in a 49.9% volume reduction. Comparison of the 2 procedures revealed significant volume reduction after open lateral capsular shift compared with arthroscopic plication (P = .00001). Repeated measurements confirmed that the injection technique was valid and reproducible. Conclusions: The lateral capsular shift resulted in significantly greater volume reduction compared with arthroscopic plication. Based on these results, we recommend an open lateral-based capsular shift for patients with multidirectional instability in which a larger capsular shift is required. However, additional plication sutures may allow for an even further reduction in volume. The amount of volume reduction required to eliminate instability still remains unknown for patients with shoulder instability caused by capsular laxity. Level of Evidence: Level IV Case Series, in vitro anatomic comparison of 2 surgical procedures.

Key Words:  Shoulder instability , Plication , Capsular shift