BACKGROUND: The rotator cuff tendon is known to exert a shear force between the 
superficial and deep layers. Owing to this characteristic, separate repair of 
delaminated rotator cuff tears has been introduced for the restoration of the 
physiological biomechanics of the rotator cuff. However, whether conventional en 
masse repair or separate repair is superior is controversial in terms of 
outcomes.
PURPOSE: To compare clinical outcomes between conventional en masse repair and 
separate double-layer double-row repair for the treatment of delaminated rotator 
cuff tears.
STUDY DESIGN: Randomized controlled study; Level of evidence, 2.
METHODS: Between August 2007 and March 2014, a total of 82 patients who 
underwent arthroscopic rotator cuff repair of a delaminated tear were enrolled 
and randomized into 2 groups. In group 1 (n = 48), arthroscopic conventional en 
masse repair was performed. In group 2 (n = 34), separate double-layer 
double-row repair was performed. The American Shoulder and Elbow Surgeons score, 
Constant score, Simple Shoulder Test score, and visual analog scale (VAS) score 
for pain and range of motion (ROM) were assessed before surgery; at 3, 6, and 12 
months after surgery; and at the last follow-up visit. Magnetic resonance 
imaging (MRI) was performed at 12 months postoperatively to examine the retear 
rate and pattern.
RESULTS: There was no significant difference between groups in the preoperative 
demographic data, including patient age, sex, symptom duration, tear size, and 
functional scores (P > .05). The mean follow-up period was 25.9 ± 1.2 months. 
Significant improvements in functional and pain scores were observed in both 
groups at the last follow-up visit. However, no significant differences in 
functional scores and ROM were found between the 2 groups at each time point, 
except that group 2 had significantly lower VAS pain scores (P < .05) at 3, 6, 
and 12 months postoperatively. Eight (17%) of 48 patients in group 1 and 6 (18%) 
of 34 patients in group 2 showed retears on MRI at 12-month follow-up (P > .05).
CONCLUSION: Both conventional en masse repair and separate double-layer 
double-row repair were effective in improving clinical outcomes in the treatment 
of delaminated rotator cuff tears. Lower pain scores were seen in patients who 
underwent separate double-layer double-row repair.