Biomechanical comparison between single-row with triple-loaded suture anchor and suture-bridge double-row rotator cuff repair.

BACKGROUND: Numerous biomechanical and clinical studies comparing different techniques for rotator cuff repair have been reported, yet universal consensus regarding the superior technique has not achieved. A medially-based single-row with triple-loaded suture anchor (also referred to as the Southern California Orthopedic Institute [SCOI] row) and a suture-bridge double-row (SB-DR) with Push-Locks have been shown to result in comparable improvement in treating rotator cuff tear, yet the biomechanical difference is unknown. The purpose of the current study was to determine whether a SCOI row repair had comparable initial biomechanical properties to a SB-DR repair. METHODS: Six matched pairs of fresh-frozen cadaveric shoulders with full-thickness supraspinatus tendon tears we created were included. Two different repairs were performed for each pair (SCOI row and SB-DR methods). Specimens were mounted on a material testing machine to undergo cyclic loading, which was cycled from 10 to 100 N at 1 Hz for 500 cycles. Construct gap formation was recorded at an interval of 50 cycles. Samples were then loaded to failure and modes of failure were recorded. Repeated-measures analysis of variance and pair-t test were used for statistical analyses. RESULTS: The construct gap formation did not differ between SCOI row and SB-DR repairs (P = 0.056). The last gap displacement was 1.93 ± 0.37 mm for SCOI row repair, and 1.49 ± 0.55 mm for SB-DR repair. The tensile load for 5 mm of elongation and ultimate failure were higher for SCOI row repair compared to SB-DR repair (P = 0.011 and 0.028, respectively). The ultimate failure load was 326.34 ± 11.52 N in the SCOI row group, and 299.82 ± 27.27 N in the SB-DR group. Rotator cuff repair with the SCOI row method failed primarily at the suture- tendon interface, whereas pullout of the lateral row anchors was the primary mechanism of failure for repair with the SB-DR method. CONCLUSION: Rotator cuff repair with the SCOI row method has superior biomechanical properties when compared with the SB-DR method. Therefore, SCOI row repair using a medially-based single-row technique with triple-loaded suture anchor is recommended to improve the initial strength in treating full-thickness rotator cuff tears.

[Modeling of Abdominal Wall-Cecum Injury Adhesion and the Anti-adhesion Mechanism of mXG].

OBJECTIVE: To construct the adhesion model of abdominal wall-cecum injury and explore the prevention and treatment effect of modified xyloglucan (mXG) thermosensitive hydrogel on abdominal wall-cecal injury adhesion. METHODS: SD rats were used to construct the abdominal wall-cecal injury adhesion model. Model mice were randomly divided into blank control group (Control), commercial chitosan membrane Control group (Film) and mXG thermosensitive hydrogel group (Hydrogel), each group contained 16 rats.In the Hydrogel group, 1 mL 4% (m/V) mXG solution was smeared on the wound surface of abdominal wall and the cecum, then closed the abdomen after gel was formed (3 min).In the Film group, 2 cm×3 cm chitosan anti-adhesion Film was applied onto the wound surface of the abdominal wall before abdominal closure.In the Control group, 1 mL normal saline was applied onto the wound surface of abdominal wall and the cecum before abdominal closure.On 7 and 14 d after the operation, rats'abdominal cavity was opened by surgery to examine and score the adhesion grade between the abdominal wall and the cecum, with double-blind design.Meanwhile, the adhesion tissue or wound tissue was taken and stained by HE, Masson and Van Gieson to histological evaluate the anti-adhesion effect.The expression of transforming growth factor-ß1 (TGF-ß1) and connective tissue growth factor (CTGF) was determined by immunohistochemical staining as well. Another group of 12 SD rat models were subjected to mXG thermosensitive hydrogel intervention.At the 1 and 6 weeks postoperation, rats main organs such as heart, liver, spleen, lung and kidney were taken for histological examination with HE staining for the purpose of evaluation the toxicity of mXG in vivo. RESULTS: Adhesion grade evaluation results showed that Film group rats occurred mild adhesion, Control group rats occurred severe adhesion, while in Hydrogel group hardly rats occured adhesion, and the differences were statistically significant(P < 0.05). Histological results showed that the Hydrogel group rats recovered well at 7 d after surgery.In healing wound tissue, no mutated tissue was observed, but a certain degree of inflammatory cell infiltration was still existed. At 14 d after surgery, the inflammation cells in the wound were significantly reduced, and the healing tissue containing only a small amount of collagen fibers under the neonatal mesothelial layer.But the other two groups showed different degrees of adhesion at the 7 and 14 d post surgery.Immunohistochemical staining showed that the expression of TGF-ß1 and CTGF in the Hydrogel group were both weaker than those in the other groups, and the difference was statistically significant (P < 0.05). In vivo toxicity tests did not show significant changes in the structure of the organs of mXG gel intervention rats at different time points. CONCLUSION: mXG thermosensitive hydrogel plays a good role in physical isolation during the key period of adhesion formation and effectively prevent the occurrence of cecum-abdominal adhesion.