Fig. 2A–B.

(A) AP knee laxity was measured with the a prescribed knee flexion angle, constrained axial tibial rotation in the neutral position, and the unconstrained translations in the coronal plane during the application of the cyclic AP shear loads. Adapted from Murray MM, Palmer M, Abreu E, Spindler KP, Zurakowski D, Fleming BC. Platelet-rich plasma alone is not sufficient to enhance suture repair of the ACL in skeletally immature animals: an in vivo study. J Orthop Res. 2009;27:639–645, with permission from John Wiley and Sons. (B) ACL structural properties were assessed with the knee flexion angle set at 30° initially. The tibia was mounted to the base of the MTS through a sliding X-Y platform while the femur was unconstrained to rotations so that the specimen could seek its own position to ensure that the load was distributed over the entire ACL cross-section. Adapted from Fleming BC, Spindler KP, Palmer MP, Magarian EM, Murray MM. Collagen-platelet composites improve the biomechanical properties of healing anterior cruciate ligament grafts in a porcine model. Am J Sports Med. 2009;37:1554–1563, with permission from Sage.