Concurrent validity and inter trial reliability of a single inertial measurement unit for spatial-temporal gait parameter analysis in patients with recent total hip or total knee arthroplasty

Accelerometer approach for anticipatory postural adjustments assessment during step initiation in patients with leprosy

Anticipatory postural adjustments (APAs) involve a complex coordination of sensorimotor information that can be impaired in diseases that affect nerve conduction. Assessing APAs typically requires costly video recording technology, posing a challenge to the study of postural changes. This hurdle is compounded in impoverished communities affected by diseases such as leprosy, which often receive limited government support. Recent years have seen the validation of inertial sensors in wearable devices and smartphones for APA analysis in diverse populations, including adults, the elderly and people with Parkinson's disease. This progress offers economically efficient alternatives for the study of APA in leprosy. Do patterns of activation of anticipatory postural adjustment differ between leprosy patients and healthy controls? We also investigated the validity and replicability of APAs recorded in leprosy patients using inertial measurements and video capture recordings. Thirty healthy individuals in the control group and 30 individuals with leprosy in the leprosy group performed ten gait initiation trials. To record the APA for gait initiation, the participants stood on a 2 m platform. Each participant was informed that the experimenter would give an signal, after which the participant would initiate a two-step walk on the platform. Inertial recordings (low-cost method) and video capture recordings (gold-standard method) from center of mass displacements were used to extract the APA before gait initiation. The results show that APAs are similar between groups (control and leprosy), but leprosy patients have less consistent APAs. In addition, this study highlights the reproducibility and high correlation between the values of variables obtained from both instruments, the video recording as gold standard method and portable digital inertial sensor as a low-cost alternative method. These promising findings support the use of affordable inertial sensors to track and record APAs in underserved populations that lack easy access to gold standard methods such as video recording. This approach has the potential to improve the therapeutic care and rehabilitation of these patients. Although not currently part of official protocols for leprosy patients, this assessment method could prove particularly valuable in situations where significant sensorimotor impairments are suspected or documented.

Toward Personalized Orthopedic Care: Validation of a Smart Knee Brace

Introduction

Wearable technology offers a promising solution to advance current rehabilitation strategies for post-operative orthopedic care. The aim of this study was to determine the level of agreement and concurrent validity of a smart knee brace compared to the gold standard measurement system GAITRite® for assessing lower limb gait parameters.

Methods

Thirty-four healthy participants were fitted with the smart knee brace (Digital Knee®) on their dominant limb. Gait parameters (stride length, stride time, and gait velocity) were measured simultaneously using the Digital Knee® and the GAITRite® electronic walkway. Two walks were performed at a comfortable speed and two at a fast-walking speed.

Results

At a comfortable walking speed, stride time was moderately valid (ICC2,1 = 0.66 s), and stride length and gait velocity demonstrated poor validity (ICC2,1 = 0.29; ICC2,1 = 0.41). All gait parameters demonstrated poor validity at a fast-walking speed (ICC2,1 = -0.16 to -0.01). Bias ranged from -0.08 to 0.28, with more clinically acceptable percentage errors at a comfortable walking speed (14.1-30%) versus at a fast-walking speed (26.4-42.6%). Gait velocity and stride length had substantially higher biases in the fast-walking speed compared to the comfortable walking speed (0.28 ± 0.39 m s-1 vs. 0.02 ± 0.21 m s-1; 0.15 ± 0.23 m vs. -0.04 ± 0.17 m). Limits of agreement were considered narrower for stride time compared to stride length and gait velocity.

Conclusion

The Digital Knee® is a promising approach to improving post-operative rehabilitation outcomes in patients with osteoarthritis. The Digital Knee® demonstrated good agreement and moderate concurrent validity for measuring gait metrics at a comfortable walking speed. These findings highlight the opportunity of the wearable sensor as an intervention for post-operative orthopedic care. This was a laboratory-based study; thus, further research is required to validate the wearable sensor in real-world contexts and in patients with knee pathologies. Further, refinement of the algorithm for measuring gait metrics at slow- and fast-walking speed with the Digital Knee® is warranted.

Instrumented treadmill for run biomechanics analysis: a comparative study

This study aims compare the spatiotemporal and kinematic running parameters obtained by the WalkerView (Tecnobody, Bergamo, Italy) with those recorded by a optoelectronic 3D motion capture system. Seventeen participants were simultaneously recorded by the WalkerView and a motion capture system during running tests on the WalkerView at two different speeds (i.e., 8 km/h and 10 km/h). Per each parameter and speed the Root Mean Square Error (RMSE), the intraclass correlation coefficient (ICC), and the mean of the difference (MOD) and limits of agreement (LOAs) indexes obtained from Bland-Altman analysis were used to compare the two systems. ICCs show an excellent agreement for the mean step time and the cadence at both testing speeds (ICC=0.993 at 8 km/h; ICC=0.998 at 10 km/h); a lower agreement was found for all the kinematic variables. Small differences for some spatio-temporal parameters and greater differences for the kinematic variables were found. Therefore, WalkerView could represent a practical, accessible, and less expensive tool for clinicians, researchers, and sports trainers to assess the characteristics spatio-temporal parameters of running in non-laboratory settings.

Inertial Sensors for Hip Arthroplasty Rehabilitation: A Scoping Review

The objective of this scoping review is to characterize the current panorama of inertia sensors for the rehabilitation of hip arthroplasty. In this context, the most widely used sensors are IMUs, which combine accelerometers and gyroscopes to measure acceleration and angular velocity in three axes. We found that data collected by the IMU sensors are used to analyze and detect any deviation from the normal to measure the position and movement of the hip joint. The main functions of inertial sensors are to measure various aspects of training, such as speed, acceleration, and body orientation. The reviewers extracted the most relevant articles published between 2010 and 2023 in the ACM Digital Library, PubMed, ScienceDirect, Scopus, and Web of Science. In this scoping review, the PRISMA-ScR checklist was used, and a Cohen's kappa coefficient of 0.4866 was applied, implying moderate agreement between reviewers; 23 primary studies were extracted from a total of 681. In the future, it will be an excellent challenge for experts in inertial sensors with medical applications to provide access codes for other researchers, which will be one of the most critical trends in the advancement of applications of portable inertial sensors for biomechanics.

Validity and reliability of the Apple Health app on iPhone for measuring gait parameters in children, adults, and seniors

This study assessed the concurrent validity and test-retest-reliability of the Apple Health app on iPhone for measuring gait parameters in different age groups. Twenty-seven children, 28 adults and 28 seniors equipped with an iPhone completed a 6-min walk test (6MWT). Gait speed (GS), step length (SL), and double support time (DST) were extracted from the gait recordings of the Health app. Gait parameters were simultaneously collected with an inertial sensors system (APDM Mobility Lab) to assess concurrent validity. Test-retest reliability was assessed via a second iPhone-instrumented 6MWT 1 week later. Agreement of the Health App with the APDM Mobility Lab was good for GS in all age groups and for SL in adults/seniors, but poor to moderate for DST in all age groups and for SL in children. Consistency between repeated measurements was good to excellent for all gait parameters in adults/seniors, and moderate to good for GS and DST but poor for SL in children. The Health app on iPhone is reliable and valid for measuring GS and SL in adults and seniors. Careful interpretation is required when using the Health app in children and when measuring DST in general, as both have shown limited validity and/or reliability.

Functional assessment of total hip arthroplasty using inertial measurement units: Improvement in gait kinematics and association with patient-reported outcome measures

Inertial measurement units (IMUs) are commonly used for gait assessment, yet their potential for quantifying improvements in gait function and patterns after total hip arthroplasty (THA) has not been fully explored. The primary aim of this study was to compare spatiotemporal parameters and sagittal plane kinematic patterns of patients with hip osteoarthritis (OA) before and after THA, and to asymptomatic controls. The secondary aim was to assess the association between dynamic hip range of motion (ROM) during walking and the Hip Osteoarthritis Outcome Scores (HOOS). Twenty-four patients with hip OA and 24 matched asymptomatic controls completed gait analyses using the RehaGait® sensor system. Patients were evaluated pre- and 1 year postoperatively, controls in a single visit. Differences in kinematic data were analyzed using statistical parametric mapping, and correlations between dynamic hip ROM and HOOS were calculated. Walking speed and stride length significantly increased (+0.08 m/s, p = 0.019; +0.06 m, p = 0.048) after THA but did not reach the level of asymptomatic controls (-0.11 m/s, p = 0.028; -0.14 m, p = 0.001). Preoperative hip and knee kinematics differed significantly from controls. After THA, they improved significantly and did not differ from controls. Dynamic hip flexion-extension ROM correlated positively with all HOOS subscores (r > 0.417; p ≤ 0.001). The change in HOOS symptoms in patients was explained by the combination of baseline HOOS symptoms and change in dynamic hip ROM (r²  = 0.748) suggesting that the additional information gained with IMU gait analysis helps to complement and objectify patient-reported outcome measures pre- and postoperatively and monitor treatment-related improvements.

Reliability and Discriminative Validity of Wearable Sensors for the Quantification of Upper Limb Movement Disorders in Individuals with Dyskinetic Cerebral Palsy

Background-Movement patterns in dyskinetic cerebral palsy (DCP) are characterized by abnormal postures and involuntary movements. Current evaluation tools in DCP are subjective and time-consuming. Sensors could yield objective information on pathological patterns in DCP, but their reliability has not yet been evaluated. The objectives of this study were to evaluate (i) reliability and (ii) discriminative ability of sensor parameters. Methods-Inertial measurement units were placed on the arm, forearm, and hand of individuals with and without DCP while performing reach-forward, reach-and-grasp-vertical, and reach-sideways tasks. Intra-class correlation coefficients (ICC) were calculated for reliability, and Mann-Whitney U-tests for between-group differences. Results-Twenty-two extremities of individuals with DCP (mean age 16.7 y) and twenty individuals without DCP (mean age 17.2 y) were evaluated. ICC values for all sensor parameters except jerk and sample entropy ranged from 0.50 to 0.98 during reach forwards/sideways and from 0.40 to 0.95 during reach-and-grasp vertical. Jerk and maximal acceleration/angular velocity were significantly higher for the DCP group in comparison with peers. Conclusions-This study was the first to assess the reliability of sensor parameters in individuals with DCP, reporting high between- and within-session reliability for the majority of the sensor parameters. These findings suggest that pathological movements of individuals with DCP can be reliably captured using a selection of sensor parameters.

Supervised versus unsupervised rehabilitation following total knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

Outcomes after total knee arthroplasty (TKA) are strongly influenced by the adequacy of rehabilitation and the consequent functional recovery. The economic impact of rehabilitation it is not negligible. Inpatient rehabilitation can be 5 to 26 times more expensive than the home-based rehabilitation. This topic is extremely relevant as the COVID-19 pandemic has highlighted the importance of unsupervised rehabilitation in orthopedic surgery. The aim of this review and meta-analysis is to investigate the scientific evidence regarding the comparison between supervised and unsupervised rehabilitation following TKA.

MATERIALS AND METHODS

Following PRISMA guideline, a comprehensive search of PubMed, Cochrane and Scopus databases using combinations of keywords and MeSH descriptors: "total "Knee replacement," "Arthroplasty", "Rehabilitation" was performed from inception to December 2021. All relevant articles were retrieved, and their bibliographies were searched for further relevant references. Only English written randomized controlled trials comparing supervised and unsupervised rehabilitation following TKA were included in this systematic review. The outcomes considered were long-term pain, physical function, knee flexion and extension ROM, 6 minute walking test (6MWT) and timed up and go test (TUG).

RESULTS

11 studies (2.181 patients in total) were included in this systematic review. The long-term pain outcome showed no significant differences (Std. Mean Difference [SMD] = 0.00, 95 % confidence interval [CI] -0.16, 0.017) between the supervised (n = 397) and unsupervised (n = 255). Physical function showed no significant differences among the two groups (mean difference [MD] = 0.84, 95 % CI = -1.82, 3.50). Non-significant differences were also found for knee ROM flexion (mean difference [MD] = -0.46, 95 % CI = -2.95, 2.04) and for knee extension (mean difference [MD] = 0.54, 95 % CI = -0.89, 1.97). At the 52-week follow-up, the unsupervised group showed significant better results in 6MWT (mean difference [MD] = -26.10, 95 % CI = -47.62, -4.59) and in Timed up and go test (mean difference [MD] = 1.33, 95 % CI = 0.50, 2.15).

CONCLUSION

This systematic review did not show a significant clinical difference in improving pain, function, and mobility outcomes after TKA between supervised PT and unsupervised PT. Therefore, it would appear that supervised rehabilitation did not had additional benefits compared to unsupervised rehabilitation.

Relationship between labral length and symptoms in patients with acetabular dysplasia before rotational acetabular osteotomy

The aim of this study was to investigate the relationship between acetabular labral length and symptoms in patients with acetabular dysplasia. In a retrospective medical record review, 218 patients with acetabular dysplasia who had undergone rotational acetabular osteotomy were identified. After implementing the inclusion and exclusion criteria, 53 patients were analyzed for preoperative symptoms measured by the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), acetabular bone morphology parameters by anteroposterior pelvic radiographs and labral parameters by radial magnetic resonance imaging. Spearman's correlation coefficients were calculated among JHEQ scores, bone morphologic parameters and labral parameters. Multiple linear regression models to determine the predictive variables of JHEQ score and labral length were obtained. There was no correlation between bone morphologic parameters and JHEQ scores. Labral length measured anteriorly correlated with JHEQ pain {r [95% confidence interval (CI)] = -0.335 (-0.555, -0.071), P = 0.014}, movement subscale [r (95% CI) = -0.398 (-0.603, -0.143), P = 0.003], mental subscale [r (95% CI) = -0.436 (-0.632, -0.188), P = 0.001] and total JHEQ score [r (95% CI) = -0.451 (-0.642, -0.204), P = 0.001]. The multiple linear regression results showed that anterior labral length was independently associated with JHEQ subscales in some models. Meanwhile, age, acetabular head index and total JHEQ score were independently associated with anterior labral length in all models. Labral length, notably in anterosuperior area, in patients with symptomatic acetabular dysplasia was related to patient's symptom. Labral length may be an important objective image finding that can be used to assess the severity of cumulative hip instability.

Association of Muscle Mass, Muscle Strength, and Muscle Function with Gait Ability Assessed Using Inertial Measurement Unit Sensors in Older Women

Aging-related muscle atrophy is associated with decreased muscle mass (MM), muscle strength (MS), and muscle function (MF) and may cause motor control, balance, and gait pattern impairments. This study determined associations of three speed-based gait variables with loss of MM, MS, and MF in older women. Overall, 432 older women aged ≥65 performed appendicular skeletal muscle, handgrip strength, and five times sit-to-stand test to evaluate MM, MS, and MF. A gait test was performed at three speeds by modifying the preferred walking speed (PWS; slower walking speed (SWS); faster-walking speed (FWS)) on a straight 19 m walkway. Stride length (SL) at PWS was significantly associated with MM. FWS and coefficient of variance (CV) of double support phase (DSP) and DSP at PWS showed significant associations with MS. CV of step time and stride time at SWS, FWS, and single support phase (SSP) at PWS showed significant associations with MF. SL at PWS, DSP at FWS, CV of DSP at PWS, stride time at SWS, and CV of SSP at PWS showed significant associations with composite MM, MS, and MF variables. Our study indicated that gait tasks under continuous and various speed conditions are useful for evaluating MM, MS, and MF.

Usefulness of gait parameters obtained from inertial sensors attached to the lower trunk and foot for assessment of gait performance in the early postoperative period after total knee arthroplasty

BACKGROUND

This study was performed to (i) compare gait parameters obtained from inertial sensors attached to the lower trunk and foot between patients in the early postoperative period after total knee arthroplasty (TKA) and healthy age- and sex-matched controls and (ii) elucidate the association between the gait parameters and patient-reported outcome measures (PROMs).

METHOD

The gait performance of 19 patients who had undergone TKA was assessed using inertial sensors and PROMs obtained from the Knee Injury and Osteoarthritis Outcome Score (KOOS) 1 week before hospital discharge. The patients walked along a 15-m walkway and we calculated the following gait parameters: walking speed, coefficient of variation (CV) of stride time, unbiased autocorrelation coefficient (AC), harmonic ratio (HR), and symmetry index (SI). The same gait parameter data from 19 age- and sex-matched healthy adults (controls) were obtained from our past study.

RESULTS

The TKA group demonstrated slower walking speed, larger CV of stride time, lower HR in all three directions, lower AC in the vertical direction, and higher SI in the vertical direction than the healthy control group (all p < 0.05). Correlation analysis revealed that the SI in the anteroposterior direction was significantly correlated with the KOOS symptoms subscore and ADL subscore (p < 0.05).

CONCLUSIONS

Patients in the early postoperative period after TKA exhibited worse gait performance as assessed by inertial sensors compared with healthy controls. Gait symmetry was correlated with PROMs. These results indicate the usefulness of assessing gait parameters after TKA.

Clinical-Functional Evaluation and Test-Retest Reliability of the G-WALK Sensor in Subjects with Bimalleolar Ankle Fractures 6 Months after Surgery

Ankle fractures can cause significant functional impairment in the short and long term. In recent years, gait analysis using inertial sensors has gained special relevance as a reliable measurement system. This study aimed to evaluate the differences in spatiotemporal gait parameters and clinical−functional measurements in patients with bimalleolar ankle fracture and healthy subjects, to study the correlation between the different variables, and to analyze the test−retest reliability of a single inertial sensor in our study population. Twenty-two subjects with bimalleolar ankle fracture six months after surgery and eleven healthy subjects were included in the study. Spatiotemporal parameters were analyzed with the G-WALK sensor. Functional scales and clinical measures were collected beforehand. In the ankle fracture group, the main differences were obtained in bilateral parameters (effect size: 0.61 ≤ d ≤ 0.80). Between-group differences were found in cadence, speed, stride length, and stride time (effect size: 1.61 ≤ d ≤ 1.82). Correlation was moderate (0.436 < r < 0.554) between spatiotemporal parameters and clinical−functional measures, explaining up to 46% of gait performance. Test−retest reliability scores were high to excellent (0.84 ≤ ICC ≤ 0.98), with the worst results in the gait phases. Our study population presents evident clinical−functional impairments 6 months after surgery. The G-WALK can be considered a reliable tool for clinical use in this population.

Comparative Analysis of Optoelectronic Accuracy in the Laboratory Setting Versus Clinical Operative Environment: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

The optoelectronic camera source and data interpolation process serve as the foundation for navigational integrity in robotic-assisted surgical platforms. The current systematic review serves to provide a basis for the numerical disparity observed when comparing the intrinsic accuracy of optoelectronic cameras versus accuracy in the laboratory setting and clinical operative environments.

METHODS

Review of the PubMed and Cochrane Library research databases was performed. The exhaustive literature compilation obtained was then vetted to reduce redundancies and categorized into topics of intrinsic accuracy, registration accuracy, musculoskeletal kinematic platforms, and clinical operative platforms.

RESULTS

A total of 465 references were vetted and 137 comprise the basis for the current analysis. Regardless of application, the common denominators affecting overall optoelectronic accuracy are intrinsic accuracy, registration accuracy, and application accuracy. Intrinsic accuracy equaled or was less than 0.1 mm translation and 0.1 degrees rotation per fiducial. Controlled laboratory platforms reported 0.1 to 0.5 mm translation and 0.1 to 1.0 degrees rotation per array. Accuracy in robotic-assisted spinal surgery reported 1.5 to 6.0 mm translation and 1.5 to 5.0 degrees rotation when comparing planned to final implant position.

CONCLUSIONS

Navigational integrity and maintenance of fidelity of optoelectronic data is the cornerstone of robotic-assisted spinal surgery. Transitioning from controlled laboratory to clinical operative environments requires an increased number of steps in the optoelectronic kinematic chain and error potential. Diligence in planning, fiducial positioning, system registration and intra-operative workflow have the potential to improve accuracy and decrease disparity between planned and final implant position.

Femoro-Epiphyseal Acetabular Roof (FEAR) Index and Anterior Acetabular Coverage Correlate With Labral Length in Developmental Dysplasia of the Hip

PURPOSE

The aim of this study was to evaluate the association between labral length and radiographic parameters of lateral and anterior acetabular coverage and the femoro-epiphyseal acetabular roof (FEAR) index in patients with developmental dysplasia of the hip (DDH).

METHODS

We retrospectively analyzed data from patients with DDH who visited our hip joint clinic for the first time due to hip symptoms. DDH presence was defined as a lateral center-edge angle (LCEA) of ≤25°. The labral lengths on the anterior and lateral sides were measured on central axial and central coronal slices of T1-weighted magnetic resonance imaging, respectively. The Pearson correlation coefficients (r) and simple linear regression analyses were performed to determine the association of the lateral and anterior labral lengths with the radiographic parameters, including the LCEA, acetabular roof obliquity, FEAR index, anterior wall index, and vertical center anterior angle.

RESULTS

This study included 88 patients, with a mean age of 39.6 ± 11.8 years. There were 65 women and 23 men. The lateral and anterior labral lengths correlated with all parameters of dysplasia. Specifically, the lateral labral length had a strong positive correlation with the FEAR index (R = 0.65, P < .001). The anterior labral length had a strong negative correlation with the anterior wall index (R = -0.66, P < .001).

CONCLUSIONS

The lateral labral length had a strong positive correlation with the FEAR index. Furthermore, the anterior labral length had a correlation with the anterior dysplasia.

LEVEL OF EVIDENCE

Level III, retrospective cross-sectional study.

A Systematic Review of Diagnostic Accuracy and Clinical Applications of Wearable Movement Sensors for Knee Joint Rehabilitation

In clinical practice, only a few reliable measurement instruments are available for monitoring knee joint rehabilitation. Advances to replace motion capturing with sensor data measurement have been made in the last years. Thus, a systematic review of the literature was performed, focusing on the implementation, diagnostic accuracy, and facilitators and barriers of integrating wearable sensor technology in clinical practices based on a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. For critical appraisal, the COSMIN Risk of Bias tool for reliability and measurement of error was used. PUBMED, Prospero, Cochrane database, and EMBASE were searched for eligible studies. Six studies reporting reliability aspects in using wearable sensor technology at any point after knee surgery in humans were included. All studies reported excellent results with high reliability coefficients, high limits of agreement, or a few detectable errors. They used different or partly inappropriate methods for estimating reliability or missed reporting essential information. Therefore, a moderate risk of bias must be considered. Further quality criterion studies in clinical settings are needed to synthesize the evidence for providing transparent recommendations for the clinical use of wearable movement sensors in knee joint rehabilitation.

Accuracy of Robotic-Assisted Spinal Surgery-Comparison to TJR Robotics, da Vinci Robotics, and Optoelectronic Laboratory Robotics

BACKGROUND

The optoelectronic camera source and data interpolation serve as the foundation for navigational integrity in the robotic-assisted surgical platform. The objective of the current systematic review serves to provide a basis for the numerical disparity that exists when comparing the intrinsic accuracy of optoelectronic cameras: accuracy observed in the laboratory setting versus accuracy in the clinical operative environment. It is postulated that there exists a greater number of connections in the optoelectronic kinematic chain when analyzing the clinical operative environment to the laboratory setting. This increase in data interpolation, coupled with intraoperative workflow challenges, reduces the degree of accuracy based on surgical application and to that observed in controlled musculoskeletal kinematic laboratory investigations.

METHODS

Review of the PubMed and Cochrane Library research databases was performed. The exhaustive literature compilation obtained was then vetted to reduce redundancies and categorized into topics of intrinsic optoelectronic accuracy, registration accuracy, musculoskeletal kinematic platforms, and clinical operative platforms.

RESULTS

A total of 147 references make up the basis for the current analysis. Regardless of application, the common denominators affecting overall optoelectronic accuracy are intrinsic accuracy, registration accuracy, and application accuracy. Intrinsic accuracy of optoelectronic tracking equaled or was less than 0.1 mm of translation and 0.1° of rotation per fiducial. Controlled laboratory platforms reported 0.1 to 0.5 mm of translation and 0.1°-1.0° of rotation per array. There is a huge falloff in clinical applications: accuracy in robotic-assisted spinal surgery reported 1.5 to 6.0 mm of translation and 1.5° to 5.0° of rotation when comparing planned to final implant position. Total Joint Robotics and da Vinci urologic robotics computed accuracy, as predicted, lies between these two extremes-1.02 mm for da Vinci and 2 mm for MAKO.

CONCLUSIONS

Navigational integrity and maintenance of fidelity of optoelectronic data is the cornerstone of robotic-assisted spinal surgery. Transitioning from controlled laboratory to clinical operative environments requires an increased number of steps in the optoelectronic kinematic chain and error potential. Diligence in planning, fiducial positioning, system registration, and intraoperative workflow have the potential to improve accuracy and decrease disparity between planned and final implant position. The key determining factors limiting navigation resolution accuracy are highlighted by this Cochrane research analysis.

Inertial measurement units and application for remote healthcare in hip and knee osteoarthritis: a narrative review (Preprint)

Background

Measuring and modifying movement-related joint loading is integral to the management of lower extremity osteoarthritis (OA). Although traditional approaches rely on measurements made within the laboratory or clinical environments, inertial sensors provide an opportunity to quantify these outcomes in patients’ natural environments, providing greater ecological validity and opportunities to develop large data sets of movement data for the development of OA interventions.

Objective

This narrative review aimed to discuss and summarize recent developments in the use of inertial sensors for assessing movement during daily activities in individuals with hip and knee OA and to identify how this may translate to improved remote health care for this population.

Methods

A literature search was performed in November 2018 and repeated in July 2019 and March 2021 using the PubMed and Embase databases for publications on inertial sensors in hip and knee OA published in English within the previous 5 years. The search terms encompassed both OA and wearable sensors. Duplicate studies, systematic reviews, conference abstracts, and study protocols were also excluded. One reviewer screened the search result titles by removing irrelevant studies, and 2 reviewers screened study abstracts to identify studies using inertial sensors as the main sensing technology and a primary outcome related to movement quality. In addition, after the March 2021 search, 2 reviewers rescreened all previously included studies to confirm their relevance to this review.

Results

From the search process, 43 studies were determined to be relevant and subsequently included in this review. Inertial sensors have been successfully implemented for assessing the presence and severity of OA (n=11), assessing disease progression risk and providing feedback for gait retraining (n=7), and remotely monitoring intervention outcomes and identifying potential responders and nonresponders to interventions (n=14). In addition, studies have validated the use of inertial sensors for these applications (n=8) and analyzed the optimal sensor placement combinations and data input analysis for measuring different metrics of interest (n=3). These studies show promise for remote health care monitoring and intervention delivery in hip and knee OA, but many studies have focused on walking rather than a range of activities of daily living and have been performed in small samples (<100 participants) and in a laboratory rather than in a real-world environment.

Conclusions

Inertial sensors show promise for remote monitoring, risk assessment, and intervention delivery in individuals with hip and knee OA. Future opportunities remain to validate these sensors in real-world settings across a range of activities of daily living and to optimize sensor placement and data analysis approaches.

Does Posterior Cruciate Ligament Retention or Sacrifice in Total Knee Replacement Affect Proprioception? A Systematic Review

Background: Proprioception is an important part of the somatosensory system involved in human motion control, which is fundamental for activities of daily living, exercise, and sport-specific gestures. When total knee arthroplasty (TKA) is performed, the posterior cruciate ligament (PCL) can be retained, replaced, or discarded. The PCL seems to be responsible for maintaining the integrity of the joint position sense (JPS) and joint kinesthesia. The aim of this review was to assess the effect of PCL on knee joint proprioception in total knee replacement. Methods: This systematic review was conducted within five electronic databases: PubMed, Scopus, Web of Science, Cochrane, and PEDro with no data limit from inception to May 2021. Results: In total 10 publications were evaluated. The analysis was divided by proprioception assessment method: direct assessment (JPS, kinesthesia) and indirect assessment (balance). Conclusions: The current evidence suggest that the retention of the PCL does not substantially improve the joint proprioception after TKA. Due to the high heterogeneity of the studies in terms of design, proprioception outcomes, evaluation methods, further studies are needed to confirm the conclusions. In addition, future research should focus on the possible correlation between joint proprioception and walking function.

Validity Analysis of WalkerViewTM Instrumented Treadmill for Measuring Spatiotemporal and Kinematic Gait Parameters

The detection of gait abnormalities is essential for professionals involved in the rehabilitation of walking disorders. Instrumented treadmills are spreading as an alternative to overground gait analysis. To date, the use of these instruments for recording kinematic gait parameters is still limited in clinical practice due to the lack of validation studies. This study aims to investigate the performance of a multi-sensor instrumented treadmill (i.e., WalkerView^TM, WV) for performing gait analysis. Seventeen participants performed a single gait test on the WV at three different speeds (i.e., 3 km/h, 5 km/h, and 6.6 km/h). In each trial, spatiotemporal and kinematic parameters were recorded simultaneously by the WV and by a motion capture system used as the reference. Intraclass correlation coefficient (ICC) of spatiotemporal parameters showed fair to excellent agreement at the three walking speeds for steps time, cadence, and step length (range 0.502–0.996); weaker levels of agreement were found for stance and swing time at all the tested walking speeds. Bland–Altman analysis of spatiotemporal parameters showed a mean of difference (MOD) maximum value of 0.04 s for swing/stance time and WV underestimation of 2.16 cm for step length. As for kinematic variables, ICC showed fair to excellent agreement (ICC > 0.5) for total range of motion (ROM) of hip at 3 km/h (range 0.579–0.735); weaker levels of ICC were found at 5 km/h and 6.6 km/h (range 0.219–0.447). ICC values of total knee ROM showed poor levels of agreement at all the tested walking speeds. Bland–Altman analysis of hip ROM revealed a higher MOD value at higher speeds up to 3.91°; the MOD values of the knee ROM were always higher than 7.67° with a 60° mean value of ROM. We demonstrated that the WV is a valid tool for analyzing the spatiotemporal parameters of walking and assessing the hip’s total ROM. Knee total ROM and all kinematic peak values should be carefully evaluated, having shown lower levels of agreement.

Validity of a New 3-D Motion Analysis Tool for the Assessment of Knee, Hip and Spine Joint Angles during the Single Leg Squat

Aim: Study concurrent validity of a new sensor-based 3D motion capture (MoCap) tool to register knee, hip and spine joint angles during the single leg squat. Design: Cross-sectional. Setting: University laboratory. Participants: Forty-four physically active (Tegner ≥ 5) subjects (age 22.8 (±3.3)) Main outcome measures: Sagittal and frontal plane trunk, hip and knee angles at peak knee flexion. The sensor-based system consisted of 4 active (triaxial accelerometric, gyroscopic and geomagnetic) sensors wirelessly connected with an iPad. A conventional passive tracking 3D MoCap (OptiTrack) system served as gold standard. Results: All sagittal plane measurement correlations observed were very strong for the knee and hip (r = 0.929–0.988, p < 0.001). For sagittal plane spine assessment, the correlations were moderate (r = 0.708–0.728, p < 0.001). Frontal plane measurement correlations were moderate in size for the hip (ρ = 0.646–0.818, p < 0.001) and spine (ρ = 0.613–0.827, p < 0.001). Conclusions: The 3-D MoCap tool has good to excellent criterion validity for sagittal and frontal plane angles occurring in the knee, hip and spine during the single leg squat. This allows bringing this type of easily accessible MoCap technology outside laboratory settings.

Agreement between the GAITRite® System and the Wearable Sensor BTS G-Walk® for measurement of gait parameters in healthy adults and Parkinson's disease patients

Background

Nowadays, the most widely used types of wearable sensors in gait analysis are inertial sensors. The aim of the study was to assess the agreement between two different systems for measuring gait parameters (inertial sensor vs. electronic walkway) on healthy control subjects (HC) and patients with Parkinson's disease (PD).

Methods

Forty healthy volunteers (26 men, 14 women, mean age 58.7 ± 7.7 years) participated in the study and 24 PD patients (19 men, five women, mean age 62.7 ± 9.8 years). Each participant walked across an electronic walkway, GAITRite, with embedded pressure sensors at their preferred walking speed. Concurrently a G-Walk sensor was attached with a semi-elastic belt to the L5 spinal segment of the subject. Walking speed, cadence, stride duration, stride length, stance, swing, single support and double support phase values were compared between both systems.

Results

The Passing-Bablock regression slope line manifested the values closest to 1.00 for cadence and stride duration (0.99 ≤ 1.00) in both groups. The slope of other parameters varied between 0.26 (double support duration in PD) and 1.74 (duration of single support for HC). The mean square error confirmed the best fit of the regression line for speed, stride duration and stride length. The y-intercepts showed higher systematic error in PD than HC for speed, stance, swing, and single support phases.

Conclusions

The final results of this study indicate that the G-Walk system can be used for evaluating the gait characteristics of the healthy subjects as well as the PD patients. However, the duration of the gait cycle phases should be used with caution due to the presence of a systematic error.