The Biomechanical Benefit of a Freely Moving System Knee Joint with a Dynamic Extension Stop

Summary: Knee-ankle-foot orthoses (KAFOs) with freely moving system knee joints are often prescribed for patients with neurological gait disorders to achieve security and stability when walking and standing. In these types of orthotic joints, extension stops are used to prevent the pathological hyperextension of the knee. A dynamic extension stop enables controlled extension of the knee through the adjustable resistance of the anterior spring unit without restricting the patient’s range of motion. The article first describes the biomechanical benefit of this innovative functional element and then presents the results of a case study that determined that a KAFO with a dynamic extension stop improves joint kinematics compared to a KAFO with a static extension stop.