Mougin, F.; Begon, M.; Desmyttere., G.; Bleau, J.; Nault, M.-L.; Cherni, Y.

Background: Anterior cruciate ligament (ACL) injuries frequently lead to altered gait biomechanics and muscle activation patterns, increasing the risk of osteoarthritis. Knee braces are commonly used to address these issues although a lack of consensus remains regarding their clinical benefits. The recent emergence of 3D-printed braces, lighter and personalized, could improve rehabilitation. Objectives: To evaluate the effect of a novel custom-made 3D-printed knee brace (Provoke) in individuals after unilateral ACL reconstruction during walking. The brace incorporates an asymmetrical hinge system aimed at stabilizing the knee joint while minimizing compensatory movements. Methods: Fourteen participants with unilateral ACL reconstruction wore the Provok brace while walking at comfortable and fast paces. Knee kinematics and kinetics, and muscular activity (rectus femoris, vastus medialis, and semitendinosus) were assessed with and without the brace. Two-tailed non-parametric paired T-tests were used to assess the biomechanical effect of the brace. Results and conclusions: The Provoke brace improved knee kinematics, facilitating a more neutral knee position by reducing valgus angles (-1.95 deg), and increasing flexion angles (+1.14 deg). Additionally, it enhanced muscle activation, particularly of the rectus femoris, suggesting improved quadriceps function. Overall, the Provok brace effectively improves knee function and reduces muscle imbalances in individuals undergoing ACL reconstruction. It may help prevent further injury and reduce the risk of post-traumatic osteoarthritis development. The long-term effects of brace use in ACL rehabilitation must be investigated.