Kinematic changes in patients with severe knee osteoarthritis are a result of reduced walking speed rather than disease severity

Proposal and validation of an equation to identify sarcopenia using bioelectrical impedance analysis-derived parameters

OBJECTIVE

This study aimed to develop a simpler approach for diagnosing sarcopenia by using only bioelectrical impedance vector analysis parameters.

METHODS

The study design was a cross-sectional study. The research was conducted based on the Itabashi Longitudinal Study on Aging, a community-based cohort study, with data collected from the 2022 and 2023 surveys in Itabashi Ward, Tokyo, Japan. The development cohort consisted of 1146 participants from the 2022 survey, and the validation cohort included 656 participants from the 2023 survey. Both cohorts were comprised of community-dwelling older adults with similar inclusion criteria. Sarcopenia was defined according to the Asian Working Group for Sarcopenia 2019 criteria. The logistic model utilized height divided by impedance at 50 kHz and phase angle to establish a new regression equation to identify sarcopenia. Regression equations were generated for the development cohort and validated for the validation cohort. Discriminatory ability was assessed using the area under the receiver operating characteristic curve (AUC) for men and women.

RESULTS

The prevalence of sarcopenia was 20.7% and 14.8% in the development and validation cohort, respectively. The AUC (95% confidence interval) of the logistic model in discriminating sarcopenia was 0.92 (0.88, 0.95) for men and 0.82 (0.78, 0.86) for women in the development cohort and 0.85 (0.78, 0.91) for men and 0.90 (0.86, 0.95) for women in the validation cohort.

CONCLUSION

The study demonstrated that a simple formula using bioelectrical parameters at 50 kHz proved useful in identifying sarcopenia in the older adult population.

Speed-dependent modulations of muscle modules in the gait of people with radiographical and asymptomatic knee osteoarthritis and elderly controls: Case-control pilot study

This study investigates the muscle modules involved in the increase of walking speed in radiographical and asymptomatic knee osteoarthritis (KOA) patients using tensor decomposition. The human body possesses redundancy, which is the property to achieve desired movements with more degrees of freedom than necessary. The muscle module hypothesis is a proposed solution to this redundancy. While previous studies have examined the pathological muscle activity modulations in musculoskeletal diseases such as KOA, they have focused on single muscles rather than muscle modules. Moreover, most studies have only examined the gait of KOA patients at a single speed, leaving the way in which gait speed affects gait parameters in KOA patients unclear. Assessing this influence is crucial for determining appropriate gait speed and understanding why preferred gait speed decreases in KOA patients. In this study, we apply tensor decomposition to muscle activity data to extract muscle modules in KOA patients and elderly controls during walking at different speeds. We found a muscle module comprising hip adductors and back muscles that activate bimodally in a gait cycle, specific to KOA patients when they increase their walking speed. These findings may provide valuable insights for rehabilitation for KOA patients.

An interaction model for predicting brace migration and validation through walking experiment

Brace migration undermines therapeutic efficacy, which is traditionally evaluated through walking experiments. This study developed an interaction model that considered the instantaneous center of rotation (ICR) misalignment to predict migration. The model was validated by walking experiment. Results show a strong positive correlation for four-linkage (FL) (r = 0.952, p < 0.01, root mean squared error (RMSE) = 0.53 mm) and spur gear (SG) (r = 0.898, p < 0.01, RMSE = 1.35 mm) mechanisms. The FL exhibits lower migration than SG (p < 0.05). In conclusion, the interaction model accurately predicts migration, emphasizing the influence of mechanism on migration.

Detection of kinematic abnormalities in persons with knee osteoarthritis using markerless motion capture during functional movement screen and daily activities

Background: The functional movement screen (FMS) has been used to identify deficiencies in neuromuscular capabilities and balance among athletes. However, its effectiveness in detecting movement anomalies within the population afflicted by knee osteoarthritis (KOA), particularly through the application of a family-oriented objective assessment technique, remains unexplored. The objective of this study is to investigate the sensitivity of the FMS and daily activities in identifying kinematic abnormalities in KOA people employing a markerless motion capture system. Methods: A total of 45 persons, presenting various Kellgren-Lawrence grades of KOA, along with 15 healthy controls, completed five tasks of the FMS (deep squat, hurdle step, and in-line lunge) and daily activities (walking and sit-to-stand), which were recorded using the markerless motion capture system. The kinematic waveforms and discrete parameters were subjected to comparative analysis. Results: Notably, the FMS exhibited greater sensitivity compared to daily activities, with knee flexion, trunk sagittal, and trunk frontal angles during in-line lunge emerging as the most responsive indicators. Conclusion: The knee flexion, trunk sagittal, and trunk frontal angles during in-line lunge assessed via the markerless motion capture technique hold promise as potential indicators for the objective assessment of KOA.

Neuropathic-like pain in knee osteoarthritis: exploring differences in knee loading and inflammation. A cross-sectional study

BACKGROUND

A subgroup of patients with knee osteoarthritis (OA) reports symptoms attributable to a neuropathic cause. Little to no attention has been invested on investigating differences in knee loading and inflammation in these patients.

AIM

To explore differences in inflammation and knee loading in patients with knee OA categorized based on the presence of neuropathic-like pain.

DESIGN

Cross-sectional study.

SETTING

Ghent University Hospital, Ghent, Belgium.

POPULATION

Knee OA patients.

METHODS

cross-sectional analysis of data from 96 patients (mean age 64.18±7.11 years) with primary knee OA participating in a randomized controlled trial. Participants were divided into three groups (unlikely, possible and indication of neuropathic-like pain) according to the modified painDETECT questionnaire (mPDQ). Data on demographics, symptoms and physical function were obtained by questionnaires. Effusion/synovitis and bone marrow lesions (BMLs) were measured using magnetic resonance imaging. Knee loading variables (knee adduction moment [KAM], KAM impulse, and knee flexion moment [KFM]) were assessed by 3D-motion analysis. One-way analysis of covariance (ANCOVA), Chi-square test and curve analyses were used to analyze continuous, categorical and loading variables respectively. Multinomial logistic regression was used to identify predictors for neuropathic-like pain.

RESULTS

Patients with indication of neuropathic-like pain exhibited higher KAM impulse compared to those with no indication of neuropathic-like pain (standard mean difference (SMD): -0.036 Nm normalized to body weight and height per second, 95% CI: -0.071, -0.001) along with greater pain intensity (SMD: 3.87 units, 95% CI: 1.90, 5.84), stiffness (SMD: 1.34 units, 95% CI: 0.19, 2.48) and worse physical function (SMD: 13.98 units 95% CI: 7.52, 20.44). Curve analysis showed no significant differences in KFM and KAM between groups. Effusion/synovitis and BMLs did not differ significantly between groups. The best predictors for indication of neuropathic-like pain were KAM impulse, Hoffa and sex.

CONCLUSIONS

Knee OA patients with indication of neuropathic-like pain exhibited higher dynamic medial loading, greater pain severity and worse physical function, while inflammatory markers were not significantly different across mPDQ groups. Future longitudinal studies are warranted to strengthen the evidence and establish mechanisms to explain associations between neuropathic-like pain and knee loading.

CLINICAL REHABILITATION IMPACT

Knee loading is a modifiable factor and patients with neuropathic-like pain may benefit from offloading interventions.

Evaluation of lumbar and hip movement characterization and muscle activities during gait in patients with knee osteoarthritis

Patients with knee osteoarthritis (KOA) might have gait deviations, but few previous studies have discussed gait compensatory movements of the proximal and distal parts of muscle groups related to KOA. The study aimed to measure lumbar and hip movements during gait test and collect muscle activities of the lower extremities. Thirty-four participants with KOA and 28 healthy participants aged over 50 years were recruited for this study. Lumbar and hip motions during walking test were measured using inertial measurement units. Four muscle groups of the lower extremity (erector spinae, gluteus maximus, quadriceps muscle, and gastrocnemius) activities in gait were collected using surface EMGs. KOA patients used an 2.12∘anterior inclined lumbar spine (p = 0.007) and 22.94∘ flexed hip (p = 0.001) in gait compared to healthy participants. The KOA patients had a small hip movement range 30.19∘(p = 0.001) and a higher asymmetric stance time ratio 0.39 (p = 0.006). Patients with KOA showed decreased erector spinae and gluteus maximus muscle activation and increased activation of the quadriceps and gastrocnemius muscles during gait. In conclusion, patients with KOA used a hyperlordotic lumbar and hip flexed strategy, which overactivates distal extensor muscles through the whole gait and might cause overstress on the lower extremity joints.

Inter-segment coordination amplitude and variability during gait in patients with knee osteoarthritis and asymptomatic adults

BACKGROUND

Inter-segment coordination examines the timing and coupling of multiple body segments and provides a complex understanding of how the neuromuscular system controls the body. Research is required to examine if inter-segment coordination during gait differs between individuals with different knee osteoarthritis (OA) severities and asymptomatic adults.

RESEARCH QUESTION

Do inter-segment coordination amplitude and between-trial variability during gait differ between individuals with varying levels of knee OA severity and asymptomatic adults?

METHODS

This observational, cross-sectional study included participants with mild/moderate knee OA (n = 38), severe knee OA (n = 24), and asymptomatic adults (n = 51). Participants ambulated overground at self-selected speeds. Data were collected with an eight-camera motion capture system and two force plates. Continuous relative phase (CRP) was used to quantify sagittal plane inter-segment coordination amplitude and between-trial variability for the thigh-shank and shank-foot pairs. Hierarchical linear models examined if CRP variables were related to the group (asymptomatic, mild/moderate OA, severe OA) after accounting for gait speed and gait phase.

RESULTS

Thigh-shank CRP amplitude was significantly associated with group variables. The severe OA group had lower CRP amplitudes than both asymptomatic (b=8.57, 95 % confidence interval=2.75-14.38) and mild/moderate OA (b=5.69, 95 % confidence interval=-0.25 to 11.62) groups. Thigh-shank CRP variability was also associated with group. The severe OA group had lower CRP variability than the asymptomatic group (b=0.45, 95 % confidence interval=0.12-0.78); there were no differences between severe and mild/moderate OA groups (p > 0.050). There were no significant associations between any of the shank-foot CRP measures and the groups.

SIGNIFICANCE

Lower thigh-shank CRP amplitude and variability in individuals with severe knee OA represents a more rigid motor system. These individuals could be attempting to stabilize their knee in response to a loss of passive stability or in response to pain. They might have difficulty adapting their gait to perturbations.

Accelerations Recorded by Simple Inertial Measurement Units with Low Sampling Frequency Can Differentiate between Individuals with and without Knee Osteoarthritis: Implications for Remote Health Care

Determining the presence and severity of knee osteoarthritis (OA) is a valuable application of inertial measurement units (IMUs) in the remote monitoring of patients. This study aimed to employ the Fourier representation of IMU signals to differentiate between individuals with and without knee OA. We included 27 patients with unilateral knee osteoarthritis (15 females) and 18 healthy controls (11 females). Gait acceleration signals were recorded during overground walking. We obtained the frequency features of the signals using the Fourier transform. The logistic LASSO regression was employed on the frequency domain features as well as the participant's age, sex, and BMI to distinguish between the acceleration data from individuals with and without knee OA. The model's accuracy was estimated by 10-fold cross-validation. The frequency contents of the signals were different between the two groups. The average accuracy of the classification model using the frequency features was 0.91 ± 0.01. The distribution of the selected features in the final model differed between patients with different severity of knee OA. In this study, we demonstrated that using logistic LASSO regression on the Fourier representation of acceleration signals can accurately determine the presence of knee OA.

The effect of complex decongestive therapy on spatio-temporal parameters and balance in women with breast cancer-related upper extremity unilateral lymphedema

BACKGROUND

The aim of this study was to investigate the effect of complex decongestive therapy on spatio-temporal parameters and balance in individuals with breast cancer-related upper extremity unilateral lymphedema.

METHODS

The study was designed as a prospective, cross-sectional study. Thirty sessions of complex decongestive therapy were applied. Participants' pre-and post-treatment spatio-temporal parameters and balance parameters were evaluated with the Win Track platform. In addition, the Timed Up and Go test was used to evaluate the dynamic balance. Plethysmography, a water displacement method, was used to measure upper extremity volume.

FINDINGS

Significant improvement was observed in limb volume asymmetry after complex decongestive therapy. While the stride length of the affected side was 409.93 mm before the treatment, it increased to 500.93 mm after the treatment, and a significant increase was observed (p = 001). Significant improvements were found in the other spatio-temporal parameters of the participants. Compared to the pre-treatment, a significant decrease was detected in the average cadence value, Timed Up and Go value, double stance time, and maximum plantar pressure point of the participants. Significant improvements were found in the participants' balance.

INTERPRETATION

Complex decongestive therapy applied to individuals with unilateral upper extremity lymphedema provides significant improvement in both spatio-temporal and balance parameters. However, we recommend complex decongestive therapy as an effective and safe treatment to reduce the volume of lymphedema. Patients with unilateral lymphedema that may cause postural asymmetry should be informed about balance and gait disturbance and should be encouraged to receive lymphedema treatment as soon as possible.

Classification of Center of Mass Acceleration Patterns in Older People with Knee Osteoarthritis and Fear of Falling

(1) Background: The preoccupation related to the fall, also called fear of falling (FOF) by some authors is of interest in the fields of geriatrics and gerontology because it is related to the risk of falling and subsequent morbidity of falling. This study seeks to classify the acceleration patterns of the center of mass during walking in subjects with mild and moderate knee osteoarthritis (KOA) for three levels of FOF (mild, moderate, and high). (2) Method: Center-of-mass acceleration patterns were recorded in all three planes of motion for a 30-meter walk test. A convolutional neural network (CNN) was implemented for the classification of acceleration signals based on the different levels of FOF (mild, moderate, and high) for two KOA conditions (mild and moderate). (3) Results: For the three levels of FOF to fall and regardless of the degree of KOA, a precision of 0.71 was obtained. For the classification considering the three levels of FOF and only for the mild KOA condition, a precision of 0.72 was obtained. For the classification considering the three levels of FOF and only the moderate KOA condition, a precision of 0.81 was obtained, the same as in the previous case, and finally for the classification for two levels of FOF, a high vs. moderate precision of 0.78 was obtained. For high vs. low, a precision of 0.77 was obtained, and for the moderate vs. low, a precision of 0.8 was obtained. Finally, when considering both KOA conditions, a 0.74 rating was obtained. (4) Conclusions: The classification model based on deep learning (CNN) allows for the adequate discrimination of the acceleration patterns of the moderate class above the low or high FOF.

Objective gait assessment in individuals with knee osteoarthritis using inertial sensors: A systematic review and meta-analysis

BACKGROUND

Objective assessment of gait using inertial sensors has shown promising results for functional evaluations in individuals with knee osteoarthritis (OA). However, the large number of possible outcome measures calls for a systematic evaluation of most relevant parameters to be used for scientific and clinical purposes.

AIM

This systematic review and meta-analysis aimed to identify gait parameters derived from inertial sensors that reflect gait deviations in individuals with knee OA compared to healthy control subjects (HC).

METHODS

A systematic search was conducted in five electronic databases (Medline, Embase, Web of Science, CINAHL, IEEE) to identify eligible articles. Risk of bias was assessed using a modified version of the Downs and Black scale. Data regarding study population, experimental procedures, and biomechanical outcomes were extracted. When a gait parameter was reported by a sufficient number of studies, a random-effects meta-analysis was conducted using the inverse variance method.

RESULTS

Twenty-three articles comparing gait between 411 individuals with knee OA and 507 HC were included. Individuals with knee OA had a lower gait speed than HC (standardized mean difference = -1.65), driven by smaller strides with a longer duration. Stride time variability was slightly higher in individuals with knee OA than in HC. Individuals with knee OA walked with a lower range of motion of the knee during the swing phase, less lumbar motion in the coronal plane, and a lower foot strike and toe-off angle compared to HC.

SIGNIFICANCE

This review shows that inertial sensors can detect gait impairments in individuals with knee OA. Large standardized mean differences found on spatiotemporal parameters support their applicability as sensitive endpoints for mobility in individuals with knee OA. More advanced measures, including kinematics of knee and trunk, may reveal gait adaptations that are more specific to knee OA, but compelling evidence was lacking.

The Effect of Fatigue on Lower Limb Joint Stiffness at Different Walking Speeds

The aim of this study was to assess the stiffness of each lower limb joint in healthy persons walking at varying speeds when fatigued. The study included 24 subjects (all male; age: 28.16 ± 7.10 years; height: 1.75 ± 0.04 m; weight: 70.62 ± 4.70 kg). A Vicon three-dimensional analysis system and a force plate were used to collect lower extremity kinematic and kinetic data from the participants before and after walking training under various walking situations. Least-squares linear regression equations were utilized to evaluate joint stiffness during single-leg support. Three velocities significantly affected the stiffness of the knee and hip joint (p < 0.001), with a positive correlation. However, ankle joint stiffness was significantly lower only at maximum speed (p < 0.001). Hip stiffness was significantly higher after walking training than that before training (p < 0.001). In contrast, knee stiffness after training was significantly lower than pre-training stiffness in the same walking condition (p < 0.001). Ankle stiffness differed only at maximum speed, and it was significantly higher than pre-training stiffness (p < 0.001). Walking fatigue appeared to change the mechanical properties of the joint. Remarkably, at the maximum walking velocity in exhaustion, when the load on the hip joint was significantly increased, the knee joint’s stiffness decreased, possibly leading to joint instability that results in exercise injury.

Gait variability between younger and older adults: An equality of variance analysis

BACKGROUND

To estimate gait variability, several methods have been routinely used which provide a measure of global variability. A recent study introduced a group waveform variability method which provides a point-by-point measurement of data variance equality. This can identify where in the gait cycle the significant differences in variability exist.

RESEARCH QUESTION

Do waveform differences exist in equality of variance and group means in lower limb biomechanical variables between healthy younger and older adults during a gait task?

METHODS

Twenty healthy younger (19-44 years old, age=29.9(7.0) years, body mass index= 24.6(3.2)kg/m², females= 10) and 20 healthy older (55-79 years old, age=63.6(5.5) years, body mass index= 25.9(2.7)kg/m², females= 10) adults who were free from lower limb injuries and had no musculoskeletal or neurological disorders. Temporospatial outcomes, sagittal and frontal lower limb joint angles and moments, along with joint powers were examined as participants walked at a self-selected pace. Waveform patterns were normalized to the gait cycle and compared using equality of variance and statistical parametric mapping techniques.

RESULTS

No difference in walking speed existed between the younger or older groups (P > .05). The older group had greater variability (P < .05) in sagittal hip angles, as well as greater frontal ankle angle and moment variability. The younger group had significantly greater mean (P < .05) ankle power generation prior to toe-off.

SIGNIFICANCE

This study provided a baseline of temporal differences in variance between healthy younger and older individuals. Its findings warrant the use of the equality of variance test to compare temporal differences for a variety of populations and tasks. Older adults generally had more variability than the younger adults, with many differences occurring near the transition from double- to single-limb support. The statistical parametric mapping analysis showed that the older adults could not generate as much ankle power as the younger adults prior to toe-off.

Osteoarthritis year in review 2021: mechanics

Osteoarthritis (OA) has a complex, heterogeneous and only partly understood etiology. There is a definite role of joint cartilage pathomechanics in originating and progressing of the disease. Although it is still not identified precisely enough to design or select targeted treatments, the progress of this year's research demonstrates that this goal became much closer. On multiple scales - tissue, joint and whole body - an increasing number of studies were done, with impressive results. (1) Technology based instrument innovations, especially when combined with machine learning models, have broadened the applicability of biomechanics. (2) Combinations with imaging make biomechanics much more precise & personalized. (3) The combination of Musculoskeletal & Finite Element Models yield valid personalized cartilage loads. (4) Mechanical outcomes are becoming increasingly meaningful to inform and evaluate treatments, including predictive power from biomechanical models. Since most recent advancements in the field of biomechanics in OA are at the level of a proof op principle, future research should not only continue on this successful path of innovation, but also aim to develop clinical workflows that would facilitate including precision biomechanics in large scale studies. Eventually this will yield clinical tools for decision making and a rationale for new therapies in OA.

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.

Assessing Site Specificity of Osteoarthritic Gait Kinematics with Wearable Sensors and Their Association with Patient Reported Outcome Measures (PROMs): Knee versus Hip Osteoarthritis

There is a great need for quantitative outcomes reflecting the functional status in patients with knee or hip osteoarthritis (OA) to advance the development and investigation of interventions for OA. The purpose of this study was to determine if gait kinematics specific to the disease—i.e., knee versus hip OA—can be identified using wearable sensors and statistical parametric mapping (SPM) and whether disease-related gait deviations are associated with patient reported outcome measures. 113 participants (N = 29 unilateral knee OA; N = 30 unilateral hip OA; N = 54 age-matched asymptomatic persons) completed gait analysis with wearable sensors and the Knee/Hip Osteoarthritis Outcome Score (KOOS/HOOS). Data were analyzed using SPM. Knee and hip kinematics differed between patients with knee OA and patients with hip OA (up to 14°, p < 0.001 for knee and 8°, p = 0.003 for hip kinematics), and differences from controls were more pronounced in the affected than unaffected leg of patients. The observed deviations in ankle, knee and hip kinematic trajectories from controls were associated with KOOS/HOOS in both groups. Capturing gait kinematics using wearables has a large potential for application as outcome in clinical trials and for monitoring treatment success in patients with knee or hip OA and in large cohorts representing a major advancement in research on musculoskeletal diseases.

Proposed objective scoring algorithm for walking performance, based on relevant gait metrics: the Simplified Mobility Score (SMoS™)-observational study

Background

Walking is a fundamental part of living, and its importance is not limited by age or medical status. Reduced walking speed (WS), or gait velocity, is a sign of advancing age, various disease states, cognitive impairment, mental illness and early mortality. Activity levels, as defined in the literature as “daily step count” (DSC), is also a relevant measure of health status. A deterioration in our walking metrics, such as reduced WS and DSC, is associated with poor health outcomes. These objective measures are of such importance, that walking speed has been dubbed “the 6th vital sign”. We report a new objective measure that scores walking using the relevant metrics of walking speed and daily step count, into an easy-to-understand score from 0 (nil mobility) to 100 (excellent mobility), termed the Simplified Mobility Score (SMoS™). We have provided equal weighting to walking speed and daily step count, using a simple algorithm to score each metric out of 50.

Methods

Gait data was collected from 182 patients presenting to a tertiary hospital spinal unit with complaints of pain and reduced mobility. Walking speed was measured from a timed walk along an unobstructed pathway. Daily step count information was obtained from patients who had enabled step count tracking on their devices. The SMoS of the sample group were compared to expected population values calculated from the literature using 2-tailed Z tests.

Results

There were significantly reduced SMoS in patients who presented to the spinal unit than those expected at each age group for both genders, except for the 50–59 age bracket where no statistically significant reduction was observed. Even lower scores were present in those that went on to have surgical management. There was a significant correlation of SMoS scores with subjective disability scores such as the Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) in this cohort.

Conclusions

The SMoS is a simple and effective scoring tool which is demonstrably altered in spinal patients across age and gender brackets and correlates well with subjective disability scores. The SMoS has the potential to be used as a screening tool in primary and specialised care settings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02546-8.

How to compare knee kinetics at different walking speeds?

BACKGROUND

Walking speed is a confounding factor in biomechanical analyses of gait, but still many studies compare gait biomechanics at comfortable walking speed (CWS) that is likely to differ between groups or conditions. To identify gait deviation unrelated to walking speed, methods are needed to correct biomechanical data over the gait cycle for walking speed.

RESEARCH QUESTION

How to compare knee kinetics over the gait cycle at different walking speeds?

METHODS

22 asymptomatic subjects walked on a dual-belt treadmill at CWS and 4 fixed speeds. Knee moments in sagittal (KFM) and frontal plane (KAM) were calculated via inverse dynamics. The net moment differences between CWS and fixed speed were expressed as a root-mean-square error (RMSE) normalized to the range of the variable. Two methods to correct for walking speed were compared. In method 1, KFM and KAM values were estimated based on interpolation between speeds at each percentage of the gait cycle. In method 2, principal component analysis was used to extract speed related features to reconstruct KFM and KAM at the speed of interest. The accuracy of both methods was tested using a leave-one-out cross validation.

RESULTS

Walking speed influenced the magnitude and shape of KFM and KAM. To account for these speed influences using both methods, leave-one-out cross validation showed low normalized RMSE (< 5 %), with little difference between the two methods. RMSE for both reconstruction methods were up to 60 % lower than the RMSE between CWS and fixed speed.

SIGNIFICANCE

Both methods could accurately correct knee kinetics over the gait cycle for the effects of walking speed. Walking speed dependency should be incorporated in each gait laboratory's reference dataset to be able to identify gait deviations unrelated to gait speed.

Modular reorganization of gait in chronic but not in artificial knee joint constraint

It is currently unknown if modular reorganization does occur if not the central nervous system, but the musculoskeletal system is affected. The aims of this study were to investigate 1) the effects of an artificial knee joint constraint on the modular organization of gait in healthy subjects; and 2) the differences in modular organization between healthy subjects with an artificial knee joint constraint and people with a similar but chronic knee joint constraint. Eleven healthy subjects and eight people with a chronic knee joint constraint walked overground at 1 m/s. The healthy subjects also walked with a constraint limiting knee joint movement to 20°. The total variance accounted (tVAF) for one to four synergies and modular organization were assessed using surface electromyography from 11 leg muscles. The distribution of number of synergies were not significantly different between groups. The tVAF and the motor modules were not significantly affected by the artificial knee constraint. A higher tVAF for one and two synergies, as well as merging of motor modules were observed in the chronic knee constraint group. We conclude that in the short-term a knee constraint does not affect the modular organization of gait, but in the long-term a knee constraint results in modular reorganization. These results indicate that merging of motor modules may also occur when changes in the mechanics of the musculoskeletal system is the primary cause of the motor impairment.NEW & NOTEWORTHY It is currently unknown if modular reorganization does occur if not the central nervous system, but the musculoskeletal system is affected. This study showed that in the short-term a knee constraint does not affect the modular organization of gait, but in the long-term a knee constraint results in modular reorganization. These results indicate that modular reorganization may also occur when changes in the mechanics of the musculoskeletal system is the primary cause of the motor impairment.

Kinematic changes in severe hip osteoarthritis measured at matched gait speeds

Kinematic differences between patients with osteoarthritis (OA) and control participants have been reported to be influenced by gait speed. The purpose of this study was to experimentally detect the effect of walking speed on differences in spatiotemporal parameters and kinematic trajectories between patients with hip OA and age-matched asymptomatic participants using wearable sensors and statistical parametric mapping (SPM). Twenty-four patients with severe unilateral hip OA and 48 control participants were included in this study. Patients walked at a self-selected normal speed and control participants at self-selected normal and slow speeds. Spatiotemporal parameters and kinematic trajectories were measured with the inertial sensor system Rehagait®. Gait parameters were compared between patients with hip OA and control participants for normal and matched speed using SPM with independent sample t-tests. At self-selected normal speed, the patient group walked slower (-0.20 m/s, p < .001) and at lower cadence (-5.0 steps/minute, p < .001) as well as with smaller hip flexion (-7.4°, p < .001) and extension (-4.1°, p = .001), higher knee flexion during terminal stance (+8.0°, p < .001) and higher ankle dorsiflexion and plantarflexion (+7.1°, p < .001). While differences in spatiotemporal parameters and the ankle trajectory disappeared at matched speed, some clinically relevant and statistically significant differences in hip and knee trajectories remained. Most differences in sagittal plane gait kinematics between patients with hip OA and control participants were present for matched speed, and therefore appear to be associated with a disease rather than gait speed. Nevertheless, studies investigating hip kinematics in patients with hip OA should involve trials at matched speeds.

Identification of Patients with Similar Gait Compensating Strategies Due to Unilateral Hip Osteoarthritis and the Effect of Total Hip Replacement: A Secondary Analysis

Despite good clinical functional outcome, deficits in gait biomechanics exist 2 years after total hip replacement surgery. The aims of this research were (1) to group patients showing similar gait adaptations to hip osteoarthritis and (2) to investigate the effect of the surgical treatment on gait kinematics and external joint moments. In a secondary analysis, gait data of 51 patients with unilateral hip osteoarthritis were analyzed. A k-means cluster analysis was performed on scores derived via a principal component analysis of the gait kinematics. Preoperative and postoperative datasets were statistically tested between clusters and 46 healthy controls. The first three principal components incorporated hip flexion/extension, pelvic tilt, foot progression angle and thorax tilt. Two clusters were discriminated best by the peak hip extension during terminal stance. Both clusters deviated from healthy controls in spatio-temporal, kinematic and kinetic parameters. The cluster with less hip extension deviated significantly more. The clusters improved postoperatively but differences to healthy controls were still present one year after surgery. A poor preoperative gait pattern in patients with unilateral hip osteoarthritis is associated with worse gait kinematics after total hip replacement. Further research should focus on the identification of patients who can benefit from an adapted or individualized rehabilitation program.

Independent and sensitive gait parameters for objective evaluation in knee and hip osteoarthritis using wearable sensors

Background

Although it is well-established that osteoarthritis (OA) impairs daily-life gait, objective gait assessments are not part of routine clinical evaluation. Wearable inertial sensors provide an easily accessible and fast way to routinely evaluate gait quality in clinical settings. However, during these assessments, more complex and meaningful aspects of daily-life gait, including turning, dual-task performance, and upper body motion, are often overlooked. The aim of this study was therefore to investigate turning, dual-task performance, and upper body motion in individuals with knee or hip OA in addition to more commonly assessed spatiotemporal gait parameters using wearable sensors.

Methods

Gait was compared between individuals with unilateral knee (n = 25) or hip OA (n = 26) scheduled for joint replacement, and healthy controls (n = 27). For 2 min, participants walked back and forth along a 6-m trajectory making 180° turns, with and without a secondary cognitive task. Gait parameters were collected using 4 inertial measurement units on the feet and trunk. To test if dual-task gait, turning, and upper body motion had added value above spatiotemporal parameters, a factor analysis was conducted. Effect sizes were computed as standardized mean difference between OA groups and healthy controls to identify parameters from these gait domains that were sensitive to knee or hip OA.

Results

Four independent domains of gait were obtained: speed-spatial, speed-temporal, dual-task cost, and upper body motion. Turning parameters constituted a gait domain together with cadence. From the domains that were obtained, stride length (speed-spatial) and cadence (speed-temporal) had the strongest effect sizes for both knee and hip OA. Upper body motion (lumbar sagittal range of motion), showed a strong effect size when comparing hip OA with healthy controls. Parameters reflecting dual-task cost were not sensitive to knee or hip OA.

Conclusions

Besides more commonly reported spatiotemporal parameters, only upper body motion provided non-redundant and sensitive parameters representing gait adaptations in individuals with hip OA. Turning parameters were sensitive to knee and hip OA, but were not independent from speed-related gait parameters. Dual-task parameters had limited additional value for evaluating gait in knee and hip OA, although dual-task cost constituted a separate gait domain. Future steps should include testing responsiveness of these gait domains to interventions aiming to improve mobility.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04074-2.

Side to side kinematic gait differences within patients and spatiotemporal and kinematic gait differences between patients with severe knee osteoarthritis and controls measured with inertial sensors

BACKGROUND

Kinematic changes associated with knee osteoarthritis (OA) have been traditionally measured with camera-based gait analysis. Lately, inertial sensors have become popular for gait analysis with the advantage of being less time consuming and not requiring a dedicated laboratory.

RESEARCH QUESTION

Do spatiotemporal and discrete kinematic gait parameters measured with the inertial sensor system RehaGait® differ between the affected and unaffected side in patients with unilateral knee OA and between patients with severe knee OA and asymptomatic control subjects? Do these differences have a similar magnitude as those reported in the literature?

METHODS

Twenty-two patients with unilateral knee OA scheduled for total knee replacement and 46 age matched control subjects were included in this study. Spatiotemporal parameters and sagittal kinematics at the hip, knee, and ankle joint were measured using the RehaGait® system while walking at a self-selected speed for a distance of 20 m and compared between groups.

RESULTS

Patients with knee OA had slower walking speed, longer stride duration, shorter stride length and lower cadence (P < 0.001). Peak knee flexion during stance and swing was lower in the affected than the unaffected leg (-4.8° and -6.1°; P < 0.01). Peak knee flexion during stance and swing (-5.2° and -8.8°; P < 0.01) and knee range of motion during loading response and swing (-3.6° and -4.4°; P < 0.01) were lower than in the control group.

SIGNIFICANCE

These side to side differences within patients and differences between patients with knee OA and control subjects agree with known gait alterations measured with camera-based systems. The RehaGait® inertial sensor system can detect gait alterations in patients with knee OA and is suitable for gait analysis in a clinical environment.

Wearable Inertial Sensors for Gait Analysis in Adults with Osteoarthritis-A Scoping Review

Our objective was to conduct a scoping review which summarizes the growing body of literature using wearable inertial sensors for gait analysis in lower limb osteoarthritis. We searched six databases using predetermined search terms which highlighted the broad areas of inertial sensors, gait, and osteoarthritis. Two authors independently conducted title and abstract reviews, followed by two authors independently completing full-text screenings. Study quality was also assessed by two independent raters and data were extracted by one reviewer in areas such as study design, osteoarthritis sample, protocols, and inertial sensor outcomes. A total of 72 articles were included, which studied the gait of 2159 adults with osteoarthritis (OA) using inertial sensors. The most common location of OA studied was the knee (n = 46), followed by the hip (n = 22), and the ankle (n = 7). The back (n = 41) and the shank (n = 40) were the most common placements for inertial sensors. The three most prevalent biomechanical outcomes studied were: mean spatiotemporal parameters (n = 45), segment or joint angles (n = 33), and linear acceleration magnitudes (n = 22). Our findings demonstrate exceptional growth in this field in the last 5 years. 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.

Lower limb kinematics improvement after genicular nerve blockade in patients with knee osteoarthritis: a milestone study using inertial sensors

Background

Genicular nerve blockade is a possible treatment for patients with knee osteoarthritis. Pain relief and improvement in functioning is expected. This procedure could be of major interest for patients in low-income countries where total knee arthroplasty is not available for the population. This study aims at assessing the immediate benefits on pain, gait, and stairs kinematics after a genicular nerve blockade in patients suffering from knee osteoarthritis in Cameroun.

Methods

A prospective study was carried out on 26 subjects in Cameroun. A genicular nerve blockade was performed on 14 women with painful knee osteoarthritis grade 2–4. Lower limb joint angles were recorded with inertial sensors before and 1 h after injection. Patient-reported outcomes of pain and perceived difficulty were collected, as well as 10 m and 6 min walking tests. A reliability analysis of inertial sensors was performed on a sample of 12 healthy subjects by calculating the intraclass correlation coefficient and the standard error of measurement.

Results

Pain and perceived difficulty decreased significantly (p < 0.001). Cadence increased significantly in stairs climbing (upstairs: + 7.7 steps/min; downstairs: + 7.6 steps/min). There was an improvement for hip sagittal range of motion during gait (+ 9.3°) and pelvis transverse range of motion in walking upstairs (− 3.3°). Angular speed range of the knee in the sagittal plane and of the hip in the frontal plane increased significantly in stairs descent (+ 53.7°/s, + 94.5°/s).

Conclusions

This study quantified improvement of gait and stair climbing immediately after a genicular nerve blockade in patients suffering from knee OA in Cameroon. This is the first study objectifying this effect, through wearable sensors.

Trial registration

Pan African Clinical Trial Registry, PACTR202004822698484. Registered 28 March 2020 - Retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-020-03836-8.

Knee Load Distribution in Hip Osteoarthritis Patients After Total Hip Replacement

Reduced external knee adduction moments in the second half of stance after total hip replacement have been reported in hip osteoarthritis patients. This reduction is thought to shift the load from the medial to the lateral knee compartment and as such increase the risk for knee osteoarthritis. The knee adduction moment is a surrogate for the load distribution between the medial and lateral compartments of the knee and not a valid measure for the tibiofemoral contact forces which are the result of externally applied forces and muscle forces. The purpose of this study was to investigate whether the distribution of the tibiofemoral contact forces over the knee compartments in unilateral hip osteoarthritis patients 1 year after receiving a primary total hip replacement differs from healthy controls. Musculoskeletal modeling on gait was performed in OpenSim using the detailed knee model of Lerner et al. (2015) for 19 patients as well as for 15 healthy controls of similar age. Knee adduction moments were calculated by the inverse dynamics analysis, medial and lateral tibiofemoral contact forces with the joint reaction force analysis. Moments and contact forces of patients and controls were compared using Statistical Parametric Mapping two-sample t-tests. Knee adduction moments and medial tibiofemoral contact forces of both the ipsi- and contralateral leg were not significantly different compared to healthy controls. The contralateral leg showed 14% higher medial tibiofemoral contact forces compared to the ipsilateral (operated) leg during the second half of stance. During the first half of stance, the lateral tibiofemoral contact force of the contralateral leg was 39% lower and the ratio 32% lower compared to healthy controls. In contrast, during the second half of stance the forces were significantly higher (39 and 26%, respectively) compared to healthy controls. The higher ratio indicates a changed distribution whereas the increased lateral tibiofemoral contact forces indicate a higher lateral knee joint loading in the contralateral leg in OA patients after total hip replacement (THR). Musculoskeletal modeling using a detailed knee model can be useful to detect differences in the load distribution between the medial and lateral knee compartment which cannot be verified with the knee adduction moment.

Measuring gait kinematics in patients with severe hip osteoarthritis using wearable sensors

BACKGROUND

The popularity of inertial sensors in gait analysis is steadily rising. To date, an application of a wearable inertial sensor system for assessing gait in hip osteoarthritis (OA) has not been reported.

RESEARCH QUESTION

Can the known kinematic differences between patients with hip OA and asymptomatic control subjects be measured using the inertial sensor system RehaGait®?

METHODS

The patients group consisted of 22 patients with unilateral hip OA scheduled for total hip replacement. Forty-five age matched healthy control subjects served as control group. All subjects walked for a distance of 20 m at their self-selected speed. Spatiotemporal parameters and sagittal kinematics at the hip, knee, and ankle including range of motion (ROM) were measured using the RehaGait® system.

RESULTS

Patients with hip OA walked at a slower walking speed (-0.18 m/s, P < 0.001) and with shorter stride length (-0.16 m, P < 0.001), smaller hip ROM during stance (-11.6°, P < 0.001) and swing (-11.3°, P < 0.001) and smaller knee ROM during terminal stance and swing (-9.0° and-11.5°, P < 0.001). Patients had a smaller hip ROM during stance and swing and smaller knee ROM during terminal stance and swing in the affected compared to the unaffected side (P < 0.001).

SIGNIFICANCE

The differences in spatiotemporal and kinematic gait parameters between patients with hip OA and age matched control subjects assessed using the inertial sensor system agree with those documented for camera-based systems. Hence, the RehaGait® system can measure gait kinematics characteristic for hip OA, and its use in daily clinical practice is feasible.