Three-dimensional shoulder motion after teres major or latissimus dorsi tendon transfer for posterosuperior rotator cuff tears

Background: Teres major (TM) transfer and latissimus dorsi (LD) transfer are essential treatment options in patients with posterosuperior rotator cuff (RC) tears. The purpose of this study was to quantify shoulder kinematics before and after TM transfer and LD transfer in posterosuperior RC tear patients. Methods: In this prospective cohort study, we quantitatively measured shoulder movements using an electromagnetic tracking device (Flock of Birds) preoperatively and 1 year after either TM (n = 13) or LD (n = 9) tendon transfer. Additional outcome measures included the Constant score (CS), patient-reported pain, and quantitative range of motion. Scapular kinematics were evaluated during arm abduction. Results: By use of a quantitative assessment, forward flexion (from 87 degrees to 106 degrees, P =.007), abduction (from 86 degrees to 106 degrees, P =.010), and external rotation in abduction (from 52 degrees to 70 degrees, P =.019) improved. Both transfers reduced pain (from 50 to 10 mm, P <.001), and the CS improved (from 37 to 62 points, P <.001). No significant differences in postoperative improvement in pain and function were found between TM and LD tendon transfers. The TM transfer group showed increased scapular lateral rotation compared with the LD transfer group (13 degrees; 95% confidence interval [CI], 4.8 degrees to 21.7 degrees; P =.003). We were unable to detect differences between TM transfer and LD transfer in the change in protraction (3.2 degrees; 95% CI, -6.3 degrees to 12.8 degrees; P =.489) and posterior tilt (3.5 degrees; 95% CI, -3.5 degrees to 10.5 degrees; P =.313). Conclusion: Tendon transfer surgery resulted in an overall improvement in CS, pain relief, and quantitative range of motion in the treatment of an irreparable posterosuperior RC tear. Scapular lateral rotation gradually increased after TM transfer, reminiscent of RC function, whereas such an increase was not observed after LD transfer. (C) 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.