Shoulder Strength after Open versus Arthroscopic Stabilization

Abstract

Background With current techniques, the main difference between arthroscopic and open shoulder stabilization is the violation of the subscapularis tendon. No studies have looked at strength differences of internal and external rotation between these groups. Hypothesis Internal rotation strength deficits will exist in patients having undergone an open shoulder stabilization procedure compared with an arthroscopic one. Study Design Piggy-back randomized controlled trial; Level of evidence, 1. Methods Forty-eight patients (38 men, 10 women), average age, 30.6 years (range, 18–59 years), were randomized to either open (n = 24) or arthroscopic (n = 24) shoulder stabilization. Rehabilitation protocols were standardized. At a mean follow-up of 19.4 months (range, 12–36 months) from surgery, patients underwent isokinetic strength testing (concentric and eccentric peak moments at 60 deg/s and 180 deg/s). Measurements were body-mass normalized. Primary outcome was internal rotation strength at 60 deg/s. Results There were no significant differences between groups with respect to age, gender, or operative limb. There were no statistical differences between operative groups for the primary outcome of internal concentric strength at 60 deg/s (mean difference, 0.011 N·m/kg; 95% confidence interval, −0.043 to 0.066; P = .677) or secondary strength measures. When compared with the contralateral limb, strength deficits existed for both surgical groups for both internal and external rotation. Regression analysis demonstrated that arm dominance is a factor in strength deficits. Conclusion The results of this trial suggest there are no side-to-side isokinetic strength deficits between patients having an open stabilization using a subscapularis splitting approach versus arthroscopic stabilization for anterior traumatic shoulder instability at 1 year after surgery. Strength deficits exist in both groups when compared with the contralateral limb.