Rotator cuff repair with all-suture anchor enhances biomechanical properties and tendon-bone integration in a rabbit model.

Background: All-suture anchor (ASA) is a special type of suture anchor. It has been used to repair rotator cuff tears (RCTs). However, mechanical properties and tendon-bone integration at different time postoperatively remains to be unclear.

Methods: Mechanical testing and water contact angle measurements were conducted for ASA. biocompatibility was assessed using rat bone marrow stem cells (BMSCs), including live/dead cell staining and Cell Counting Kit-8 assays. ASA was implanted for rotator cuff repair (ASA group) in a New Zealand White rabbit model of RCTs, and a natural rotator cuff was used as a control (natural group). The animals were sacrificed, and tissue samples were harvested for biomechanical, radiographic, and histological analysis at 4, 8, and 12 weeks postoperatively.

Results: ASA was hydrophobic and had a strong mechanical property . The biocompatibility analysis showed that ASA had no effect on the viability of BMSCs. Mechanical testing revealed that a gradually improved failure load of ASA group was 118.0 ± 22.53N at 12 weeks postoperatively, which was recovered to the natural group. Micro-CT analysis indicated that an initial decrease in BMD and trabecular quality following ASA implantation, with a slight recovery observed at 12 weeks. Additionally, histological analysis showed the tendon-bone interface gradually integrated in the ASA group. A significant increase in tendon-bone interface scores was found from 4 weeks to 12 weeks. Tendon maturing score also improved in the ASA group, and Type I collagen content recovered to 18.58 ± 4.378 % at 12 weeks and no different from that of the natural group.

Conclusion: Rotator cuff repair with ASA in a rabbit model demonstrated the capacity to enhance biomechanical properties and tendon-bone integration.