A Portable Wearable Inertial System for Rehabilitation Monitoring and Evaluation of Patients With Total Knee Replacement

Accuracy amidst errors: Evaluating a commercially available wearable sensor system and its associated calibration procedures for monitoring sagittal knee motion in patients undergoing total knee arthroplasty

BACKGROUND

Commercially available wearable sensors monitoring knee range of motion (ROM) are gaining traction in orthopaedics, but few studies validate against optical motion capture (MOCAP) in total knee arthroplasty (TKA) patients. Furthermore, wearable calibration is essential for accurate measurements, yet few investigations evaluate calibration and ROM accuracy. This study assessed one commercial wearable sensor system's calibration (goniometric versus MOCAP) and sagittal knee angle computation accuracy in TKA patients during activities.

METHODS

Twenty TKA patients were recruited (5 lost to follow-up). Following a sensor tutorial (MotionSense, Stryker, Mahwah, NJ), participants self-applied sensors for pre-TKA data capture. TKA was then performed by one surgeon followed by identical post-TKA data captures. MOCAP and wearable sensor data were collected during activities. MOCAP sagittal knee angles (θMOCAP) were compared to two wearable sensor knee angles: 1) θCalGoni = goniometric calibration, 2) θCalMOCAP = MOCAP calibration. Two-way ANOVAs evaluated the impact of time (pre-TKA vs. post-TKA) and calibration type (goniometry vs. MOCAP) on calibration angles and wearable sensor error. Variance equality tests compared pre-TKA vs. post-TKA and goniometric vs. MOCAP calibration.

RESULTS

No significant differences were noted pre-TKA vs. post-TKA. Calibration angles differed significantly with goniometry yielding significantly more error than MOCAP. MOCAP calibration reduced error below clinically acceptable levels (<5°) during activities and with significantly less error variance.

CONCLUSION

MOCAP calibration significant improved accuracy of knee angle computations to acceptable levels (<5°). Accordingly, these wearables are suitable for continuous knee ROM monitoring after calibrating with correct angles, Future studies should investigate specific activities and sensor misplacement on angle measurements.

Randomized Controlled Studies on Smartphone Applications and Wearable Devices for Postoperative Rehabilitation After Total Knee Arthroplasty: A Systematic Review

INTRODUCTION

Smartphone and wearable technologies are novel devices for monitoring postoperative mobility and recovery in total knee arthroplasty (TKA) patients. This systematic review of the highest-level evidence studies evaluated the advantages of these technologies in postoperative care, specifically focusing on 1) smartphone applications, 2) wearable devices, and 3) their combined use.

METHODS

A systematic literature search from July 26, 2015, to June 13, 2024, identified Level-1 and -2 published studies investigating smartphone applications and wearables for monitoring post-TKA recovery. A total of 3,131 studies were screened, with 31 meeting inclusion criteria: 18 focused on applications, eight on wearables, and five on both. Study quality was evaluated using the Coleman Methodology Scoring. Key metrics analyzed included patient satisfaction scores and adherences, functional outcomes, and pain scores, ranges of motion and gait analyses, and measurements and comparison tools.

RESULTS

Among the Level 1 and 2 publications, 17 of 18 studies on smartphone applications for postoperative recovery in TKA highlighted benefits including patient satisfaction, improved gait, optimized pain management through medication scheduling guidance, cost savings, and better functional outcomes. Among the eight studies focused solely on wearable technologies, seven exhibited positive outcomes and demonstrated accuracy in monitoring and effectiveness in gait and motion analysis. Additional benefits included improved recovery outcomes, enhanced return to function, cost reduction, and better pain management through patient interaction and guidance. The five studies, which integrated both applications and wearables, corroborated these findings, emphasizing patient satisfaction and overall mobility enhancement at three months post-surgery.

DISCUSSION

Smartphone applications and wearable devices offer enhancements in postoperative rehabilitation following TKA. Randomized trials validate their accuracy, effectiveness, and utility in this context. Improved adherence to care plans and medication schedules emerged as recurrent findings. These technologies and resultant data not only provide direct patient benefits, but also promise potential cost savings.

[The potential of wearable technology in knee arthroplasty]

BACKGROUND

Wearable technology has developed rapidly in recent years and offers promising possibilities for supporting and optimizing orthopaedic procedures, especially pre- and postoperatively. The continuous monitoring and precise analysis of movement patterns, as well as the individual adaptation of rehabilitation processes are just some of the potential benefits of wearable technology. The aim of this paper is to evaluate the potential of wearable technology in knee arthroplasty and to provide an overview of the evidence that is currently available.

MATERIAL AND METHODS

This overview is based on a literature search in Medline, Cochrane Library and Web of Science databases on the topic of wearables and knee arthroplasty.

RESULTS

Wearable technology enables precise and, above all, long-term and objective monitoring of knee joint movements and loads-regardless of the setting and environment in which the patient is located. So-called IMUs (inertial measurement units), which can record multidimensional directions of movement and speed, are most commonly used for movement analysis. Due to their small size and manageable costs, IMUs are suitable for movement monitoring in orthopaedics. In addition, continuous data acquisition through the corresponding development of algorithms allows early detection of complications and almost real-time adjustment of therapy. As wearables can also be used in the home setting, a combination with other telemedical and/or feedback applications is possible in the course of increasing ambulantization. Wearable technology has the potential to significantly improve pre- and post-operative care and rehabilitation in knee arthroplasty. Through the precise monitoring of movement patterns and the individual adjustment options, better or equivalent results could be achieved in the future compared to current standards. Despite the promising results so far, the current evidence is still limited and further clinical studies are needed to comprehensively assess the long-term effectiveness and cost-effectiveness of knee arthroplasty.

The Intrarater and Interrater Reliability and Validity of Universal Goniometer, Digital Inclinometer, and Smartphone Application Measuring Range of Motion in Patients with Total Knee Arthroplasty

OBJECTIVES

The aim of this study was to investigate the intrarater and interrater reliability and validity of range of motion measurements obtained with a universal goniometer, digital inclinometer, and smartphone application in patients with total knee arthroplasty.

METHODS

Range of motion of the knee joint was measured by two examiners with a universal goniometer, digital inclinometer, and a smartphone application. Data were obtained from 51 knees of 27 patients at postoperative 6 months. Two measurements made by the first examiner were compared to assess interrater reliability, and measurements from both examiners were compared to assess intrarater reliability. Statistical analysis was performed using intraclass correlation coefficient (ICC) and Spearman's rho values.

RESULTS

With all three methods, active and passive knee flexion range of motion measurements showed high intrarater and interrater reliability (ICC = 0.749-0.949). Concurrent validity analysis also demonstrated statistically significant, moderate to strong correlation among the three methods (r = 0.775-0.941).

CONCLUSION

The universal goniometer, digital inclinometer, and smartphone application were all found to be reliable and valid assessment tools in clinical practice for patients with total knee arthroplasty.

Mobile and Computer-Based Applications for Rehabilitation Monitoring and Self-Management After Knee Arthroplasty: Scoping Review

BACKGROUND

Successful post-knee replacement rehabilitation requires adequate access to health information, social support, and periodic monitoring by a health professional. Mobile health (mHealth) and computer-based technologies are used for rehabilitation and remote monitoring. The extent of technology use and its function in post-knee replacement rehabilitation care in low and middle-income settings are unknown.

OBJECTIVE

To inform future mHealth intervention development, we conducted a scoping review to map the features and functionality of existing technologies and determine users' perspectives on telerehabilitation and technology for self-management.

METHODS

We followed the Joanna Briggs Institute methodology for scoping reviews. We searched the Embase, Medline, PsycINFO via OVID, and Cochrane Central Register of Controlled Trials databases for manuscripts published from 2001 onward. We included original research articles reporting the use of mobile or computer-based technologies by patients, health care providers, researchers, or family members. Studies were divided into the following 3 categories based on the purpose: validation studies, clinical evaluation, and end user feedback. We extracted general information on study design, technology features, proposed function, and perspectives of health care providers and patients. The protocol for this review is accessible in the Open Science Framework.

RESULTS

Of the 5960 articles, 158 that reported from high-income settings contributed to the qualitative summary (64 studies on mHealth or telerehabilitation programs, 28 validation studies, 38 studies describing users' perceptions). The highest numbers of studies were from Europe or the United Kingdom and North America regarding the use of a mobile app with or without wearables and reported mainly in the last decade. No studies were from low and middle-income settings. The primary functions of technology for remote rehabilitation were education to aid recovery and enable regular, appropriate exercises; monitoring progress of pain (n=19), activity (n=20), and exercise adherence (n=30); 1 or 2-way communication with health care professionals to facilitate the continuum of care (n=51); and goal setting (n=23). Assessment of range of motion (n=16) and gait analysis (n=10) were the commonly validated technologies developed to incorporate into a future rehabilitation program. Few studies (n=14) reported end user involvement during the development stage. We summarized the reasons for satisfaction and dissatisfaction among users across various technologies.

CONCLUSIONS

Several existing mobile and computer-based technologies facilitate post-knee replacement rehabilitation care for patients and health care providers. However, they are limited to high-income settings and may not be extrapolated to low-income settings. A systematic needs assessment of patients undergoing knee replacement and health care providers involved in rehabilitation, involving end users at all stages of development and evaluation, with clear reporting of the development and clinical evaluation can make post-knee replacement rehabilitation care in resource-poor settings accessible and cost-effective.

A Precise Hip Protection System with Multi-scale Fall Warning Algorithm Based on Offset Displacement

Falls occur frequently in daily life and the damage to the body is irreversible. Therefore, it is crucial to implement timely and effective warning and protection systems for falls to minimize the damage caused by falls. Currently, the fall warning algorithm has shortcomings such as low recognition rates for falls and fall-risk movements and insufficient lead-time, the time before the subject impacts the floor, making it difficult for falling protection devices to function effectively. In this study, a multi-scale falls warning algorithm based on offset displacement is built, and a hip protection system is designed. The performance of the algorithm and the system is validated using 150 falling and 500 fall-risk actions from 10 volunteers. The results showed that the recognition accuracy for falling actions is 98.7% and the recognition accuracy for fall-risk actions is 99.4%, with an average lead-time of 402ms. The protection rate for falling movements reached 98.7%. This proposed algorithm and hip protection system have the potential to be applied in elderly communities, hospitals, and homes to reduce the damage caused by falls.Clinical Relevance- This study provides important reference for clinicians in analyzing fall behaviors to patients at risk of falls in clinical settings, offering valuable technical support for ensuring the safety of patients in danger of falling. It also contributes to further promoting the development of falling-prevention medical devices.