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**Design and Development of Magnesium-Based Suture Anchor for Rotator Cuff Repair Using Finite Element Analysis and In Vitro Testing**  
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design-related factors associated with mechanical fixation strength against pullout force may aggravate chronic and symptomatic progression of rotator cuff tear [8; 9; 10]. Therefore, the relationships between design-related factors, including structures and materials, and mechanical strength against pullout loading are the primary considerations of studies on suture anchor design.  
To validate the primary stability of a suture anchor's fixation, studies have used finite element analysis (FEA) for diverse purposes, including the mechanical analysis of soft tissue and bone implants design [11; 12]. With FEA, designers are able to predict whether their designs are suitable for clinical use and further revise the design if they discover any problems. After the suture anchor is manufactured, the axial pullout test, following the standard operating procedure of ASTM-F543, executed during the removal of bone screws from their insertion site in bone blocks is a standard approach for quantifying the primary stability of designs [13; 14]. Several studies have not only used the testing procedure of ASTM F543 for design analysis, but also used it to study the local deformation of bone structure during a screw pullout test [15]. In addition, biomechanical experiments, such as those involving the use of a universal force moment sensor or robotic evaluation system for cadaveric and animal bones can provide predictive results under physiological conditions [16]. Several studies on orthopedic and dental implants have revealed various structural parameters that influence the primary stability of screw topology, including pitch, contact area, thread shapes, and cylindrical part dimensions [17; 18; 19].  
Materials are also crucial considerations in the mechanical and biochemical aspects of bone screw applications. Studies have extensively investigated the designs of suture anchors and conducted structural analyses using common biomaterials, such as stainless steel, titanium alloys, and biodegradable polymers [20; 21; 22; 23]. Magnesium (Mg)-based materials hold considerable promise for use with bone tissue because of their analogous strength to that of bone, strong bone integration effects, and high biocompatibility; such materials have thus received increased attention in bone implant applications [24; 25; 26]. However, suture anchors using such Mg-based materials are few, and the mechanical stability of such distinctive materials is under-investigated.  
To assess the biomechanical performance of a new suture anchor design based on an Mg-based alloy, we employed a four-factor full factorial design method (Figure 2). By  
Figure 1: Illustration of the use of a suture anchor for soft tissue repair. The suture anchor is screwed into a predrilled hole in the bone to stabilize the suture. The suture can then penetrate through the soft tissue and be tied in order to fix the soft tissue to the bone.  
assessing the effects of various combinations of distinctive parameters through FEA and ASTM F-543 tests, we developed a novel suture anchor design that exhibits mechanical strength levels and provides a durable stress distribution for more favorable clinical results.