A novel method to analyze the mechanics of unloader braces for medial knee osteoarthritis
نویسنده
چکیده
Marcus Brown Department of Mechanical and Materials Engineering, Queen’s University, Kingston, Canada Background Bracing is a treatment option for medial knee osteoarthritis [1] that unloads the medial knee through the application of an external moment (brace moment) [2]. In theory, the brace moment is designed to reduce the total external adduction moment, as disease severity and external adduction moment are correlated [3]. The braces used in this study operate according to the principle of three-point bending [2] (Figure 1). A load is applied to the lateral knee (Figure 1, FK), and two reaction forces are applied to the thigh and shank (Figure 1, FT and FS), generating the brace moment at the knee (Figure 1). According to this loading, brace moment is affected by the magnitude of the lateral load, and the distance from the lateral load to the thigh and shank reaction forces (Figure 1, dT and dS), called the thigh and shank lever arms. The magnitude of the lateral load can be controlled using adjustment screws, however the brace lever arms are defined by brace fit and design. Previous studies have quantified the brace moment using direct measurements [2] or using approximations [1,4], however no studies have considered the pressure distributions applied by the brace to the user. These are important as they can be used to better estimate the lever arm distances, and quantify the effect of design elements on brace moment. Therefore, the purpose of this study is to provide a novel means of analyzing brace mechanics, specifically by measuring the pressure distributions and lateral force applied at the knee between the brace and the user. Included in this objective is the comparison of two braces, to establish whether the proposed method is suitable to identify differences in the functionality of different brace designs.
منابع مشابه
Design Evaluation in Novel Orthoses for Patients with Medial Knee Osteoarthritis
Osteoarthritis of the knee is a debilitating condition affecting increasing numbers of individuals each year. One option for treatment is orthotic knee braces, but a little independent reviews have taken place to date on their relative outcomes for users. This study therefore evaluates the efficacy of different types of knee orthoses (braces) with regard to key aspects of use, including gait pa...
متن کاملKinematic and Kinetic Changes with Valgus Unloader Braces in Patients with Knee Osteoarthritis
INTRODUCTION Valgus unloader knee braces (VUB) are designed to decrease medial compartment knee loading and are effective at improving the clinical status of patients with knee osteoarthritis (OA) [1]. Whether medial comparment unloading is a consistent result of VUB or whether other kinematic and kinetic alterations occur while the VUB is worn during gait requires further exploration. The purp...
متن کاملUnloader Braces for Medial Compartment Knee Osteoarthritis: Implications on Mediating Progression
متن کامل
Neuromuscular Changes Associated with Valgus Unloader Braces in Patients with Knee Osteoarthritis
INTRODUCTION Valgus knee braces are effective at decreasing pain and improving function in patients with knee osteoarthritis (OA) [1]. The braces are designed to decrease loading in the medial knee compartment but previous studies are unclear if this truly occurs. Alternatively, changes in the neuromuscular system might account for the benefits of bracing. An earlier study with a small sample d...
متن کاملKnee Unloader Brace Effectiveness Using a Detailed Musculoskeltal Model: a Pilot Study
This study presents a pilot investigation into the effectiveness of unloader knee braces for osteoarthritis subjects. The unloading effect of the brace was modeled by applying a knee abduction moment as a function of the brace deflection angle, eliminating the need for load sensors on the knee brace. The use of a detailed musculoskeletal model provided the means to evaluate the relative importa...
متن کامل