Anterior cruciate ligament deficient knees are a common pathological condition for which a knee orthosis is used. The ability of a custom knee orthosis to prevent anterior displacement of the tibia is of critical importance when used on patients with an anterior cruciate ligament deficient knee. A mechanical test program was carried out to compare a novel orthotic fabrication platform, Composite Reinforcement Instead of Sidebars, with commercially available knee braces. The ability of the knee orthoses to prevent anterior tibial displacement served as the criterion for comparison in the test program. The Composite Reinforcement Instead of Sidebars knee orthoses were found to be the most effective of all braces studied in resisting tibial translation in a surrogate model of the knee. The orthoses were also about twice as effective as the competitive braces on a stiffness/weight basis.