A Novel Biomimetic Vascularized 3D Reinforced Nanocomposite Scaffold for Anterior Cruciate Ligament Repair

This study presents a novel scaffold design to enhance anterior cruciate ligament (ACL) repair outcome by overcoming the mechanical and biological limitations of existing collagen-based scaffolds. Current scaffolds require arthrotomy and show limited efficacy in young, athletic patients. We developed a Polycaprolactone (PCL)/Collagen/hydroxyapatite-nanoclay (in situ HAPclay) modified with amino valeric acid nanocomposite scaffold (using the naming convention "CO60HC10," where CO60 denotes 60% collagen content and HC10 indicates 10% in situ HAPclay), to improve mechanical properties, biodegradation, absorption, and biological activity. Scaffold formulations with varying collagen and HAPclay contents were systematically characterized, and degradation studies in simulated synovial fluid assessed performance under physiologically relevant conditions. A hollow scaffold design allows implantation over an internal Iliotibial(IT) band, which can extend for lateral extra-articular tenodesis, providing biological and biomechanical benefits. Zig-zag suture incorporation increased tensile modulus to 26.77 ± 0.12 MPa, ensuring secure handling during surgery. Moreover, the coculture of human umbilical vein endothelial cells (HUVECs) and human mesenchymal stem cells (hMSCs) confirmed vascularization potential and collagen expression. Feasibility was demonstrated through successful ACL IT band implantation in frozen human cadaver knee models (n = 2). This scaffold system holds promise for improving outcomes in high-demand young patient populations.