The effect of a knee ankle foot orthosis on lower limb kinematics and kinetics in an individual with varus knee alignment

Introduction: Increased knee loading and a varus knee deformity have been linked with progression of knee osteoarthritis and thus, reducing both of these are key treatment principles. There are different types of orthoses which are recommended to correct knee load and varus deformity, for individuals with medial knee OA, with knee valgus braces being one of these. However, these braces have been found not to reduce knee load, nor varus deformity effectively due to the need for a high force to be applied on the knee which consequently alters kinematics at the knee and hip. In order to overcome these limitations, a knee ankle foot orthosis (KAFO) may be an option. However, no such study has assessed the effect a KAFO has on the knee joint during walking and stair climbing and if it is more effective than knee valgus braces. The purpose of this thesis was therefore to assess the effectiveness of a knee-ankle-foot-orthosis (KAFO) on the kinematics and kinetics of the lower limb in the sagittal and frontal planes compared to a custom made and off-the-shelf (OTS) knee valgus braces during walking and stair climbing.Methods: One male individual (43 years) with 10 degrees of knee varus deformity was assessed in a control shoe, OTS and a custom made UnloaderOne knee valgus brace, and a custom-made KAFO during walking and stair climbing. Three-dimensional kinematics and kinetics of the hip, knee, and ankle joints were collected where the maxima and minima of the sagittal and coronal plane angles and moments were assessed with a repeated measures analysis of variance.Results: The KAFO significantly reduced external knee adduction moment (EKAM), knee adduction angular impulse (KAAI), knee varus angle, and ankle eversion compared to both valgus knee braces. In addition, the KAFO significantly improved the knee and hip flexion angles and hip range of motion in sagittal plane during level walking compared to the shoe and OTS. Neither the custom nor the OTS knee valgus braces significantly reduced EKAM or knee varus compared to the shoe.Conclusion: The KAFO has been shown to reduce knee loading and knee deformity in this individual, and much better than the commonly used knee valgus braces. From the increased lever arm and improved fit, this could be a potential avenue for treatment of these impairments in individuals when other conservative options are not successful