Development of a silk and collagen fiber scaffold for anterior cruciate ligament reconstruction

The objective of this study was to determine a silk-collagen fiber ratio for an anterior cruciate ligament (ACL) reconstruction composite scaffold device. Composite fiber scaffolds with silk volumes ≥14 % and collagen volume <86 % demonstrated comparable or greater initial ultimate tensile stress relative to the human ACL. Silk scaffolds implanted subcutaneously and intraarticularly in rabbits demonstrated an 84 and 92 % reduction in strength with a 26 and 22 % reduction in volume after 8 weeks, respectively. The mechanical degradation findings of this preliminary study suggest that a composite scaffold with an initial UTS value of at least 129 MPa, or roughly a 48:52 silk to collagen volume ratio meets the minimal mechanical requirements necessary to proceed to a functional ACL reconstruction study in vivo.