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First evaluation of a novel tri-compartment unloader

This biomechanical study 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 weight.

Second biomechanical study of a tri-compartment unloader

By using a biomechanical model of the knee, this study demonstrated a tri-compartment unloader brace (TCU) can reduce a number of contact and ligament forces across the knee during a deep knee bend. The results replicate and extend the findings of Budarick et al. 2020, which demonstrated that a TCU can reduce knee joint loading.

Research Summary

Third biomechanical study of a novel tri-compartment unloader

Effect of a tri compartment unloader knee brace on knee moments and quadriceps activity during a chair rise and lower and stair descent in individuals with knee osteoarthritis.

Bishop, E.L., Kuntze, G., and Ronsky, J.L. (2020). Osteoarthritis and Cartilage. Under Peer Review. 28: S243-S244.

Key Findings

Improved Support During Key Actions

During chair rise and lower and stair descent, wearing a TCU resulted in significantly less quadriceps muscle effort and fewer internal knee extension moments (Fig. 2, 3).

Significantly Reduced Pain Scores

Patients wearing a TCU reported significantly lower pain scores compared to other bracing conditions (Fig. 4).

Replicates & Extends Previous Research

Corroborates PF and TF unloading capabilities of a TCU, which were demonstrated in previous studies.1
Research at the McCaig Institute for Bone and Joint Health (University of Calgary) was conducted to examine the biomechanical effects of the Levitation Tri-compartment Unloader (TCU) in patients with multi-compartment knee OA. Adult patients between the ages of 45 and 75 with moderate to severe multi-compartmental knee OA were recruited to participate in the study. Following informed consent, participants were fitted with a TCU knee brace. After an acclimatization period, participants were asked to perform several activities of daily living while wearing the brace and while unbraced. Three-dimensional movement data and muscle activity data were collected from a state-of-the-art motion capture system and ground reaction forces were collected for the braced leg (Figure 1). Finally, participants were asked to report on their level of pain experienced while performing the movements without the brace and while wearing the brace.

Figure 1

A study participant wearing the Levitation brace while climbing stairs during biomechanical data collection at the Clinical Movement Assessment Lab.

Clinical study on Levitation 2 Knee brace at mccaig institute

Results demonstrate that wearing the TCU lowers quadriceps muscle effort and internal knee extension moments during a chair rise and lower movement as well as a stair descent (Figure 2). These findings are important because both of these measures have been shown to contribute to patellofemoral (PF) and tibiofemoral (TF) joint unloading. The results therefore corroborate earlier research demonstrating the capacity of a TCU to produce PF and TF joint unloading.2

This study is the first to capture the effect of wearing the TCU on quadriceps muscle activity in knee OA patients and provides strong evidence supporting the proposed mechanism of unloading the knee joint. Participants reported lower levels of pain while wearing the Levitation brace, suggesting that there is an immediate effect of the TCU on knee pain during these weight-bearing activities.

Figure 2

Knee extension moment for the chair rise and lower and stair descent in 3 brace conditions. Bars represent standard deviation and * represents significant difference between bracing conditions.

Figure 3

VM and VL muscle power for the chair rise and lower and stair descent in 3 brace conditions. Bars represent standard deviation and * represents a significant difference between bracing conditions.

Clinical study on Levitation 2 Knee brace at mccaig institute

Figure 4

Average reported pain scores (n=6) for OFF (white), LOW (grey) and HIGH (black). * represents a significant difference between bracing conditions.

Video: Research Overview

Dr. Emily Bishop presents study findings at the 2020 AOPA National Assembly

 

In this recorded session, Dr. Bishop discusses research findings on Levitation’s assistive moment and effect on pain.

Partner Institutions

University of Calgary

Spring Loaded is currently collaborating with researchers at the University of Calgary to understand how the use of the Levitation knee brace influences user-reported outcomes such as pain, knee function, quality of life, physical activity levels and use of medication and other treatments. U of C researchers are also quantifying the potential of Levitation to unload the patellofemoral and tibiofemoral knee compartments.

Mitacs

Mitacs is a national, not-for-profit organization that has designed and delivered research and training programs in Canada for 20 years. Working with 70 universities, 6,000 companies, and both federal and provincial governments, Mitacs builds partnerships that support industrial and social innovation in Canada.

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Second biomechanical study of a tri-compartment unloader
Second biomechanical study of a tri-compartment unloader

Second biomechanical study of a tri-compartment unloader

By using a biomechanical model of the knee, this study demonstrated a tri-compartment unloader brace (TCU) can reduce a number of contact and ligament forces across the knee during a deep knee bend. The results replicate and extend the findings of Budarick et al. 2020, which demonstrated that a TCU can reduce knee joint loading.

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