# The Impact of a Lightweight Pneumatic Robotic Knee Wearable on Gait

## TL;DR

A lightweight robotic knee device improved walking speed and knee function in patients with weak quadriceps, according to a case study.

## Contribution

The study demonstrates the effectiveness of a pneumatic robotic wearable in enhancing gait for individuals with extensor mechanism weakness.

## Key findings

- The active brace increased flat surface walking speed by 45% compared to no devices.
- The active brace improved knee flexion at initial contact and during stance by over 21 degrees.
- Step length during decline walking was 62% longer with the active brace.

## Abstract

Exoskeletons may provide quadriceps augmentation to patients with a torn or permanently weak extensor mechanism. Pneumatic exoskeletons utilize pressurized gas to improve gait, but their use and biomechanical impact have not been well described.

A lightweight pneumatic robotic wearable device was piloted in a clinical gait case report study using four different conditions—no devices, walking stick, inactive brace, and active brace. Walking speed, step length, step time, step width, and hip and knee flexion/extension angles were assessed while walking on a flat, declined, and inclined surface.

Walking speed on a flat surface with the active brace (0.41 ± 0.03 m/s) was 45% faster than walking with no devices (0.28 ± 0.04 m/s). Knee flexion at initial contact (19.0° ± 0.2°) and peak knee flexion during stance (19.0° ± 0.2°) were greater with the active brace than with no device (−2.3° ± 1.7° and −1.3° ± 0.7°, respectively). The active brace (0.89 ± 0.07 s) was associated with a 17% shorter step time during incline walking compared to no devices (1.06 ± 0.09 s). It was also associated with a 62% longer step length during decline walking compared to no devices (0.27 ± 0.04 vs. 0.17 ± 0.03 m).

In this case report, a pneumatic robotic knee wearable device improved quadriceps function and increased walking speed while freeing one arm to perform other tasks. A training program that optimizes function and comfort may improve device adoption as patients may need time to become acquainted with external torque delivery to the limb.