Design Evaluation of a Novel Multicompartment Unloader Knee Brace
Published in the Journal of Biomechanical Engineering
The first biomechanical study by Budarick et al 1Footnote goes here outlines the unique design and function of the Levitation knee brace and demonstrates that Levitation can reduce patellofemoral and tibiofemoral joint contact forces to a level that would be achieved by losing 45 lbs of body weight2Footnote goes here. By comparison, the OA Rehabilitator (the only other published and commercially available knee extension assist brace) reduces internal joint contact forces to a level that would be achieved by losing 5 lbs of body weight (Figure 2). The reported reduction of knee joint forces was at a static 90-degree knee bend.
Assistive moment provided by the Levitation Tri-Compartment Unloader versus the OA Rehabilitator at varying brace flexion angles . Lines of best fit (R2 = 1) are presented for each brace profile.
Effective bodyweight reduction at 90 degrees of knee flexion offered by the Levitation Tri-Compartment Unloader and the OA Rehabilitator.
implications for care
The Importance of Joint Unloading and the Effect of Weight Loss
The reduction of joint contact forces to a level that would be achieved by losing 45 pounds of body weight is important for understanding how Levitation can provide rapid pain relief and functional improvement for patients with knee OA.
Clinical guidelines for the conservative treatment of knee OA agree that weight loss is an important intervention that improves both pain and function in patients with knee OA. However, for weight loss to be effective, research has shown that patients must lose at least 10% of their starting body weight, while the largest benefits are seen in patients who achieve a >20% reduction in body weight 3Footnote goes here.
For an average individual with knee OA weighing 205 pounds, a 20% bodyweight reduction (equivalent to losing 41 pounds) can be a daunting challenge. By reducing joint forces to a level that would be achieved by losing 45 pounds of body weight, unlike any other commercially available knee brace, Levitation can provide immediate joint unloading during knee flexion (i.e., when joint forces are highest). This in turn provides patients with rapid improvements in pain and function, thereby allowing patients to resume or increase their physical activity (6,8).
For an average knee OA patient weighing 200 lbs, Levitation reduces joint loading to a level that would be achieved by losing 45 lb of body weight, a 22.5% reduction 4Footnote goes here. Previous research shows that weight loss of at least 20% is required for the best clinical outcomes in patients with knee OA17.