Comparison of Clinical and Anatomical Outcomes between Delaminated Rotator Cuff Tear and Single Layer Rotator Cuff Tear

Background: Delaminated rotator cuff tear is known to be a degenerative tear having a negative prognostic effect. This study undertook to compare the anatomical and clinical outcomes of delaminated tears and single layer tears. Methods: Totally, 175 patients with medium to large rotator cuff tears enrolled for the study were divided into 2 groups, based on the tear pathology: single layer tear (group 1) and delaminated tear (group 2). Preoperatively, length of the remnant tendon, muscle atrophy of supraspinatus (SS), and fatty degeneration of SS and infraspinatus (IS) muscles were assessed on magnetic resonance imaging (MRI). For follow-up, the repair integrity of the rotator cuff was evaluated by ultrasonography. Clinical outcomes were assessed by evaluating the Constant score (CS) and Korean Shoulder Score (KSS). Results: Retears were detected in 6 cases of group 1 (6.5%) and 11 cases of group 2 (13.3%). Although higher in group 2, the retear rate was significantly not different (p=0.133). Preoperative MRI revealed length of remnant tendon to be $15.46{\pm}3.60mm$ and $14.17{\pm}3.16mm$ (p=0.013), and muscle atrophy of SS (occupation ratio) was $60.54{\pm}13.15$ and $56.55{\pm}12.88$ (p=0.045), in group 1 and group 2, respectively. Fatty degeneration of SS and IS in both groups had no significant differences. Postoperatively, no significant differences were observed for CS and KSS values between the groups. Conclusions: Delaminated rotator cuff tears showed shorter remnant tendon length and higher muscle atrophy that correlate to a negative prognosis. These prognostic effects should be considered during delaminated rotator cuff tear treatment.