Wearable inertial sensors for gait analysis in adults with osteoarthritis – a scoping review

Abstract

Purpose: While there is no cure for OA, lower limb biomechanical data collected during walking can provide valuable information on the etiology, progression, and treatment of this disease. Unfortunately, these conventional systems can be expensive and time-consuming, which make them inaccessible to many clinicians. Fortunately, the advent of wearable inertial sensors has provided an accessible and affordable alternative to conventional optical gait analysis systems. This growing area of research has demonstrated the immense potential of these devices, but the literature remains fragmented across the broad field of OA biomechanics. Therefore, in conducting this scoping review we aimed to summarize the growing body of literature using wearable inertial sensors for gait analysis in OA. Specifically, our objective was to identify biomechanical outcomes and applications of wearable inertial sensors for assessing walking gait in adults diagnosed with lower limb OA. We aimed to highlight the quality and types of research prominent in this field, with a focus on biomechanical outcomes and important gaps to be addressed in future research. Methods: We searched six databases using predetermined search terms which highlighted the broad areas of inertial sensors, gait, and osteoarthritis on June 9, 2020. Specifically, our criteria aimed to include studies which used inertial sensors (i.e., accelerometers, gyroscopes, and/or magnetometers) for walking gait analysis in adults diagnosed with lower limb OA (e.g., hip, knee, or ankle). Studies which only examined outcomes not related to an assessment of walking gait patterns (e.g., daily step count, physical activity, energy expenditure) were not considered. Two authors independently conducted title and abstract reviews, followed by full-text screening. Study quality was also assessed by two independent reviewers. Data were extracted from included studies in areas such as study design, osteoarthritis sample, protocols, and inertial sensor outcomes. Results: Search and Screening Results. Our search strategy identified a total of 561 articles and 376 articles after duplicate removal. A total of 107 articles were passed to full-text screening which were further reduced to 72 studies included in our scoping review. The PRISMA flow diagram presented in Figure 1 documents all exclusions at the full-text level. The most common reason for exclusion at the full-text level was “no biomechanical outcomes”, which was generally the result of studies measuring only physical activity or step count data. Osteoarthritis Sample and Protocols. The gait of 2,159 adults with OA were examined using wearable inertial sensors across the 72 studies. The most common location of OA studied was the knee (n=46), followed by the hip (n=22), and the ankle (n=7). The most common placement of sensors was the back/pelvis/torso (n=41), followed closely by the shank (n=40), foot (n=31), thigh (n=27), and head/neck (n=5). The most common study design was found to be cross-sectional (n=44), with most examining differences in gait between OA and controls (n=34). There were 21 studies that utilized some type of longitudinal design, with most examining the effect of surgery (n=17) and 4 examining other interventions (e.g., exercise, gait retraining). Figure 2 illustrates the number of included studies published each year, grouped by study design. Inertial Sensor Outcomes. Mean ST parameters were the most common outcome as they were presented in 45 studies. The variability and symmetry of ST parameters were each presented in 14 studies. The second most common outcome was segment orientation or joint angles, measured in 33 studies. Linear acceleration magnitudes were the third most common and appeared in 22 studies, with estimates of variability or symmetry components surrounding these outcomes present in 10 studies. Figure 3 provides a visual representation of gait outcomes by sensor locations. Conclusions: Wearable inertial sensors provide an accessible and affordable tool to support our understanding and treatment of OA through gait analyses. We identified 72 studies which have utilized wearable inertial sensors to assess OA gait. Overall, these studies measured a wide range of outcomes from mean ST parameters to the KAM and more. Similarly, the patient populations, study designs, and sensor protocols varied greatly between studies. Two-thirds of these studies were published in the past five years (Figure 1) and we predict that 2019 may be an inflection point whereafter remarkable growth will occur in this area for years to come. While mean ST parameters remain the most assessed outcomes in OA, recent work has highlighted inertial sensors ability to measure more advanced outcomes such as knee joint angle, KAM, and impact accelerations, as well as a variety of variability and symmetry measures. Nevertheless, there remains a need for more longitudinal study designs, patient-specific models, free-living assessments, and a push for “Code Reuse” to maximize the unique capabilities of these devices and ultimately improve how we diagnose and treat this debilitating disease.View Large Image Figure ViewerDownload Hi-res image Download (PPT)View Large Image Figure ViewerDownload Hi-res image Download (PPT)