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

Abstract

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.

Fig. 1. Measurement of the remnant tendon length and evaluation of delamination was done on oblique coronal T2 weighted image in preoperative magnetic resonance imaging. (A) Remnant tendon length was measured from the midpoint of lateral edge of the torn tendon to the musculotendinous junction on the clearest image obtained of the ‘midportion of tendon’. (B) Delamination of tendon was evaluated on oblique coronal image (arrows).

Fig. 2. Muscle atrophy of supraspinatus was measured using occupation ratio at ‘Y’ view on oblique sagittal image in preoperative magnetic resonance imaging.

Fig. 3. Fatty degeneration were evaluated on axial and oblique sagittal images in the preoperative magnetic resonance imaging. (A) Supraspinatus. (B) Infraspinatus.

Fig. 4. Intraoperatively, the tear shape was evaluated at the lateral portal of bursoscopy. (A) Single layer tear. (B) Delaminated tear.

Fig. 5. Rotator cuff repair. (A) Suture bridge double row repair was done for single layer tears. (B, C) En-masse suture bridge double row repair was done in cases of delaminated tears.

Fig. 6. Repair integrity was followed by ultrasonography. (A) Intact repair integrity. (B) Retear. (A) Arrows indicate intact articular and bursal layer of repaired tendon. (B) Arrow indicates discontinuity of tendon. Rt SS: supraspinatus, Lt SS: supraspinatus.

Table 1. Comparison of Retear Rate between Single Layer Tear and Delaminated Tear

Table 2. Comparison of Factors between Two Groups

Table 3. Comparison of Factors between Retear and Non-retear Groups

Table 4. Clinical Outcomes at Final Follow-up between Single Layer Tear and Delaminated Tear