The Use of a Digital Knee Device During Rehabilitation Post Anterior Cruciate Ligament Reconstruction
van Gulden, Anja
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The anterior cruciate ligament (ACL) is a fundamental knee stabiliser and injury to the ACL often requires surgical repair. Sagittal plane knee range of motion (ROM) measurements enable clinicians to assess knee control and supporting muscular activation. Advances in digital technology have demonstrated the potential to improve rehabilitation outcomes via individualised specific feedback and increased ROM monitoring. Digital devices have been developed which may be beneficial for ACL rehabilitation, such as the Digital Knee device (OPUM, 2021). However no literature has been found investigating the use of a smart wearables in ACL rehabilitation. However, many benefits such as improved motivation, adherence and convenience have been found in other wearable rehabilitation devices, suggesting potential for translation to ACL rehabilitation. The overall purpose of this thesis was to assess the usability of a Digital Knee device during ACL rehabilitation. To investigate the measurement reliability of sagittal plane knee motion recorded on the Digital Knee device, a heel slide and sit to stand activity were completed by each participant. Following these two activities participants rested for 15-minutes with the device removed. A second session of the same two activities was completed after re-attaching the Digital Knee device. High reliability for measurement of sagittal plane knee motion was found for both the within-session (ICC = 0.96 -1.00) and between-session (ICC = 0.70 -1.00) conditions. Two instruction protocols were also trialled among the participants (text dominant and infographic dominant) to determine the effect on the device reliability. No significant differences in reliability were found between the text dominant and infographic instruction protocols. The observations in this study aligned with previous findings, denoting measurements taken on the Digital Knee will be highly repeatable during recurrent testing. To better understand the effectiveness of the Digital Knee device during rehabilitation, eight participants were recruited to use the device for six weeks post-surgery and were asked to perform a daily heel slide activity. Daily maximum sagittal knee motion was recorded on the Digital Knee device and saved to an online server. A goniometer was used to record weekly maximum sagittal knee motion in a control group. Similar average weekly knee motion was reported based on goniometer and Digital Knee 10 measurements however the recorded range was lower than expected and larger inter-subject variation was observed in the Digital Knee group. Within the six-week timeframe of the study, maximum group knee flexion was reported at 87° ± 14 (goniometer) and 86°±11 (Digital Knee). Participants also completed weekly questionnaires and a post-study semi structured interview to provide insight into the use of the device during their rehabilitation. Device users reported high levels of motivation throughout the study which they attributed to the ability to view live feedback. Compliance with the Digital Knee during the six-week period was also good (79%), which was speculated to be because of live monitoring and improved motivation. Digital Knee device users identified comfort of the device and usability of the digital interface as recommended features for future improvements. The findings from this study have been utilised by the Digital Knee device manufacturer to improve its usability in rehabilitation. Specifically, a compression sleeve has been developed to replace the rigid strap design and interface changes have been made to allow viewing of long-term personal data. Overall, this research has contributed to the development of design improvements which should improve wearability and measurement accuracy of the Digital Knee device.