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. 2019 Feb 28;19(5):1021.
doi: 10.3390/s19051021.

Verification of a Portable Motion Tracking System for Remote Management of Physical Rehabilitation of the Knee

Kevin M Bell  1   2   3 , Chukwudi Onyeukwu  4 , Michael P McClincy  5 , Marcus Allen  6 , Laura Bechard  7   8 , Abhigyan Mukherjee  9 , Robert A Hartman  10 , Clair Smith  11 , Andrew D Lynch  12 , James J Irrgang  13   14
Affiliations

Verification of a Portable Motion Tracking System for Remote Management of Physical Rehabilitation of the Knee

Kevin M Bell et al. Sensors (Basel). .

Abstract

Rehabilitation following knee injury or surgery is critical for recovery of function and independence. However, patient non-adherence remains a significant barrier to success. Remote rehabilitation using mobile health (mHealth) technologies have potential for improving adherence to and execution of home exercise. We developed a remote rehabilitation management system combining two wireless inertial measurement units (IMUs) with an interactive mobile application and a web-based clinician portal (interACTION). However, in order to translate interACTION into the clinical setting, it was first necessary to verify the efficacy of measuring knee motion during rehabilitation exercises for physical therapy and determine if visual feedback significantly improves the participant's ability to perform the exercises correctly. Therefore, the aim of this study was to verify the accuracy of the IMU-based knee angle measurement system during three common physical therapy exercises, quantify the effect of visual feedback on exercise performance, and understand the qualitative experience of the user interface through survey data. A convenience sample of ten healthy control participants were recruited for an IRB-approved protocol. Using the interACTION application in a controlled laboratory environment, participants performed ten repetitions of three knee rehabilitation exercises: heel slides, short arc quadriceps contractions, and sit-to-stand. The heel slide exercise was completed without feedback from the mobile application, then all exercises were performed with visual feedback. Exercises were recorded simultaneously by the IMU motion tracking sensors and a video-based motion tracking system. Validation showed moderate to good agreement between the two systems for all exercises and accuracy was within three degrees. Based on custom usability survey results, interACTION was well received. Overall, this study demonstrated the potential of interACTION to measure range of motion during rehabilitation exercises for physical therapy and visual feedback significantly improved the participant's ability to perform the exercises correctly.

Keywords: inertial measurement units; knee; mHealth; mobile health; physical therapy; rehabilitation.

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Conflict of interest statement

Kevin Bell, Michael McClincy, Robert Hartman, Andrew Lynch, and James Irrgang have financial interest with interACTION (University of Pittsburgh Reference #04275) being evaluated in this research study. This means that it is possible that the results of this study could lead to personal profit for the individual investigator(s) and/or the University of Pittsburgh.

Figures

Figure 1
Figure 1
(A) Yost Lab’s two 3-Space Bluetooth sensors is a 3D printed case designed to align the sensors during alignment, (B) Padded elastic straps secured on the thigh and shank, Cary, (C) Screenshot of the mobile application screen that provides the participant with visual feedback.
Figure 2
Figure 2
Bland-Altman Plots displaying the differences between the IMU and OptiTrack for the (A) heel slide, (B) SAQ, and (C) sit-to-stand exercises.
Figure 3
Figure 3
Scatterplot of the difference between the target ROM value of 60 degrees and the actual ROM for (A) the heel slides without visual feedback and (B) the heel slides with visual feedback.
Figure 4
Figure 4
Frequency bar graphs of the custom usability survey results.
Figure 5
Figure 5
Frequency bar graph of the ASQ survey results.
See this image and copyright information in PMC

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