Third biomechanical study of a novel tri-compartment offloader knee brace

Research Summary

Third biomechanical study of a novel tri-compartment OFFloader

Effect of a tri compartment OFFloader 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 TCO resulted in significantly less quadriceps muscle effort and fewer internal knee extension moments (Fig. 2, 3).

Significantly Reduced Pain Scores

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

Replicates & Extends Previous Research

Corroborates PF and TF offloading capabilities of a TCO, 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 Offloader (TCO) 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 TCO 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 TCO 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 offloading. The results therefore corroborate earlier research demonstrating the capacity of a TCO to produce PF and TF joint offloading.2

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


Dr. Emily L. Bishop

University of Calgary

Dr. Bishop is a postdoctoral fellow and clinical research associate for Spring Loaded. Based out of the McCaig Institute of Joint and Bone Health, she conducts both clinical and biomechanical research on the Levitation knee brace.

Dr. Gregor Kuntze

University of Calgary

Dr. Kuntze is a research associate whose research focuses on the biomechanical and neuromuscular consequences of musculoskeletal injury, joint pathology, and neuromotor impairment across pediatric and adult populations.

Dr. Janet L. Ronsky

University of Calgary

Dr. Ronsky is an award-winning scientist and engineer whose research focuses on joint biomechanics and technology development. She currently occupies two research chairs and is the director of the Centre of Biomechanical Research.

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 offload the patellofemoral and tibiofemoral knee compartments.


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