MAGNESIUM ALLOY ANCHOR AND ZINC ALLOY SUTURE IN LIGAMENT/TENDON-BONE RECONSTRUCTION: DEGRADATION BEHAVIOUR AND REPAIR EFFECTS

Current materials comprising suture anchors used to reconstruct ligament-bone junctions still have limitations in biocompatibility, degradability or mechanical properties. Due to the favorable mechanical properties, biocompatibility and biodegradability, the magnesium alloy anchors and zinc sutures have great application potential in ligament/tendon-bone reconstruction. Here, ZE21C magnesium alloy and TC4 titanium alloy were prepared for anchors to reconstruct the patellar ligament-tibia in SD rats. Otherwise, zinc alloy suture was applied to the supraspinatus tendon in a rat acute rotator cuff tear model with Vicryl Plus absorbable suture as a control. The performance of the magnesium alloy anchor and zinc alloy suture and their reparative effect on the ligament/tendon-bone junction were evaluated through imaging, histology, and biomechanical assays. In vivo, the ZE21C magnesium anchor and zinc alloy suture could maintain its mechanical integrity within 12 weeks of implantation. Radiological, histological, and mechanical assays indicated that the ZE21C magnesium anchor promoted bone formation above the suture anchor and healing in the ligament-bone junction, leading to better biomechanical strength than the TC4 group. Biodegradable zinc alloy suture promoted fibrocartilage interface regeneration in rat rotator cuff compared to Vicryl Plus group. The stimulation of BMP-2 and TGF-β1 as well as VEGF by Mg ions or zinc ions was responsible for the fibrocartilage regeneration of magnesium anchor and zinc suture. Moreover, the ZE21C magnesium anchor and zinc alloy suture provided sufficient fixation strength during the ligament/tendon-bone healing process. The results indicated that Mg alloy anchors and zinc alloy sutures are promising for application in rotator cuff reconstruction.