Gait mechanics contribute to exercise induced pain flares in knee osteoarthritis

Neuromuscular control strategies of the lower limb during a typical Tai Chi brush knee and twist step in practitioners with and without knee pain: a pilot study

As a complex movement, Tai Chi (TC) could be challenging for knee control, and the compensatory changes in TC biomechanics of knee pain patients are unknown. The Brush Knee and Twist Step (BKTS) is a typical TC movement that involves basic leg motion repeated in the whole TC. This pilot study examined electromyography and retro-reflective marker trajectory data to investigate neuromuscular control strategies of the lower extremity during BKTS in TC practitioners with and without knee pain. Twelve experienced TC practitioners with (n = 6) and without knee pain (n = 6) participated. Our results revealed that knee pain practitioners presented muscle imbalance in the vastus medialis-vastus lateralis and vastus lateralis-biceps femoris, and poor alignment of the knee with the toes in TC lunge. Additionally, they adaptively developed rigid coordination strategies, showing higher levels of lower limb muscle co-contraction and activity compared to controls. Training programs for TC practitioners with knee pain should be designed to modify both abnormal muscle synergy patterns and incorrect lunge during TC, which may improve exercise safety.

Improving muscle capacity utilization with a 12-week strengthening program for females with symptomatic knee osteoarthritis

BACKGROUND

Strengthening exercise improves symptoms in knee osteoarthritis (OA), but it remains unclear if biomechanical mechanisms contribute to this improvement. Muscle capacity utilization, which reflects the proportion of maximum capacity required to complete tasks, may provide insight into how strengthening exercise improves clinical outcomes in painful knee OA.

PURPOSE

The purpose of this secondary analysis was to determine if a 12-week strengthening intervention reduced muscle capacity utilization during walking, squat and lunge tasks in females with painful knee OA.

METHODS

Data from 28 females (age 59.6 ± 6.2 years old; body mass index 29.1 ± 4.7 kg/m2) with clinical knee OA were included. Participants completed a strengthening intervention 3 times per week for 12 weeks. Knee extensor isometric torque was measured on a commercial dynamometer; peak values from three exertions were averaged. Peak KFM was extracted and averaged from five walking trials. Mean KFM was extracted and averaged from three trials for each of static lunges and squats. Muscle capacity utilization was the ratio of mean peak KFM to peak extensor torque for walking; and mean KFM to peak extensor torque for squats and lunges. Paired t-tests determined differences between peak extensor torque, peak KFM and muscle capacity utilization from pre to post intervention (p < 0.05).

RESULTS & SIGNIFICANCE

Peak extensor torque increased at follow up (p = 0.02). Peak KFM during walking decreased (p = 0.005). Muscle capacity utilization during walking (p = 0.008) and squat (p = 0.002) decreased. Mean KFM and muscle capacity utilization during lunge remained unchanged from pre to post intervention. The reduction in muscle capacity utilization at follow up indicates the strengthening intervention produced a decrease in proportion of the maximal capacity a participant used to complete walking and squat tasks. Strengthening both increases maximal muscle capacity and decreases the net moment required during daily tasks in knee OA.

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.

The effects of upper- vs. lower-body aerobic exercise on perceived pain in individuals with chronic knee pain: a randomised crossover trial

Background and objectives

Some patients with chronic knee pain experience an increase in knee pain following a single bout of exercise involving their knee joint, which can negatively affect exercise adherence and thus result in reduced overall health and lack of disease management. We want to determine whether a single bout of upper-body (UB) aerobic arm-ergometry exercise is effective in reducing the experience of pain in those with chronic knee pain compared with lower-body (LB) aerobic leg ergometry exercise.

Methods

A total of 19 individuals (women = 11, men = 8; age = 63 ± 8 years; body mass index = 24 ± 3 kg/m2) who suffered from chronic knee pain for ≥3 months took part in this study. Arm-ergometry and cycle-ergometry exercises were performed for 30 min at a moderate intensity, separated by 7 days. Pain intensity was assessed by means of a visual analogue scale (VAS) pre- and post-exercise and for 7 days post-exercise. Pressure pain threshold (PPT) and mechanical detection threshold (MDT) were measured pre- and post-exercise at both local and distal anatomical sites. Data are presented as mean ± SD.

Results

VAS pain was significantly reduced (p = 0.035) at 1 day post-exercise following the UB exercise trial (-1.4 ± 0.8) when compared with the LB exercise trial (+0.1 ± 2.1). Both UB and LB exercises were effective in reducing local and distal PPT. MDT responses were heterogeneous, and no differences between the UB and LB exercise conditions were noted.

Conclusion

An acute bout of upper-body aerobic arm-ergometry exercise evoked a significant decrease in the affected knee joint pain in individuals with chronic knee pain of up to 24 h/1 day post-exercise compared with lower-body aerobic exercise. While the exact mechanisms remain unclear, upper-body exercise may offer a viable, novel therapeutic treatment for patients with chronic knee pain.

Challenges and advances in the use of wearable sensors for lower extremity biomechanics

The use of wearable sensors for the collection of lower extremity biomechanical data is increasing in popularity, in part due to the ease of collecting data and the ability to capture movement outside of traditional biomechanics laboratories. Consequently, an increasing number of researchers are facing the challenges that come with utilizing the data captured by wearable sensors. These challenges include identifying/calculating meaningful measures from unfamiliar data types (measures of acceleration and angular velocity instead of positions and joint angles), defining sensor-to-segment alignments for calculating traditional biomechanics metrics, using reduced sensor sets and machine learning to predict unmeasured signals, making decisions about when and how to make algorithms freely available, and developing or replicating methods to perform basic processing tasks such as recognizing activities of interest or identifying gait events. In this perspective article, we present our own approaches to common challenges in lower extremity biomechanics research using wearable sensors and share our perspectives on approaching several of these challenges. We present these perspectives with examples that come mostly from gait research, but many of the concepts also apply to other contexts where researchers may use wearable sensors. Our goal is to introduce common challenges to new users of wearable sensors, and to promote dialogue amongst experienced users towards best practices.

Osteoarthritis Flares

The phenomenon of flares is a common feature in the daily life of people with osteoarthritis (OA). Characterized by episodes of sudden-onset increases in signs and symptoms, their impact can often be distressing and disabling. Despite their potential to have both short-term and long-term consequences for patients across the whole course of the condition, their occurrence and optimal management are not fully understood. This article provides a contemporary perspective on defining OA flares and their potential triggers, and offers suggestions for how health professionals might explore flare patterns with patients in clinical practice and frame timely best-practice treatment approaches.

The relationship between muscle capacity utilization during gait and pain in people with symptomatic knee osteoarthritis

BACKGROUND

Muscle capacity utilization reflects the percentage of maximal knee extensor strength required to complete physical activities.

RESEARCH QUESTION

Is pain associated with muscle capacity utilization during walking in older adults with knee osteoarthritis? Secondarily, is muscle capacity utilization in older adults with knee osteoarthritis sex-specific?

METHODS

Twenty-three participants (15 females) with symptomatic knee OA completed this study [age 67 ( ± 8) years, body mass index 29.7 ( ± 3.9) kg/m², gait speed during the Six Minute Walk test 1.25 ( ± 0.25) m/s]. Pain was measured using the Knee injury and Osteoarthritis Outcome Score. Muscle capacity utilization was quantified as the peak external knee flexor moment during level walking normalized to knee extensor maximum voluntary isometric contraction. The knee flexor moment was calculated from kinematic and kinetic data during barefoot level walking at a self-selected speed and at 1.1 m/s. Knee extensor maximum voluntary isometric contraction was measured on a dynamometer. Multiple linear regressions were used to determine the relationship between pain and muscle capacity utilization after adjusting for age, sex, body mass index, and gait speed. Independent sample t-tests examined sex differences.

RESULTS

Pain was not associated with muscle capacity utilization during self-selected and standardized walking speeds (p = 0.38 and p = 0.36, respectively). Females did not require a greater muscle capacity utilization than males to complete gait at self-selected and standardized speeds (p = 0.28, and p = 0.40, respectively).

SIGNIFICANCE

Muscle capacity utilization was not associated with pain during walking in people with knee osteoarthritis. Future work should explore more challenging activities of daily living in knee OA.

Association between Abnormal Gait Patterns and an Elevated Degree of Pain after Daily Walking: A Preliminary Study

This study aimed to investigate whether abnormal gait patterns are associated with experiencing an elevated degree of pain after daily walking. In this preliminary, cross-sectional study, 223 community-dwelling older adults were assessed for pain experienced after daily walking using a simple question that involved asking the subject about their past experiences of an elevated degree of pain after walking for 400 m or more. Gait patterns were assessed using the Comprehensive Gait Assessment using InerTial Sensor score (C-GAITS score), derived from the data measured by Inertial sensors attached to the lower trunk and heel when subjects walked along a 15 m walkway at a self-selected preferred speed. The score was the sum of 10 gait parameter scores. The lower scores indicated more and worse abnormal gait patterns. In total, 24 older adults (10.8%) reported that they experienced pain after daily walking. According to the multiple logistic regression analyses, older adults with a lower total C-GAITS score had a significantly greater probability of having past experiences of pain after walking (odds ratio = 1.11, 95% confidence interval = 1.03–1.20). The findings of this study suggest that more and worse abnormal gait patterns among older adults in a clinical walking test are associated with an elevated degree of pain after daily walking.

Linking physical activity with clinical, functional, and structural outcomes: an evidence map using the Osteoarthritis Initiative

Physical activity is consistently recommended across clinical practice guidelines for managing knee osteoarthritis, yet prescription rates are low. Evidence mapping uses a systematic approach to visually illustrate and summarize published evidence, highlight gaps in the literature, and formulate research questions. The purpose of this study was to review and summarize evidence published from the Osteoarthritis Initiative (OAI) linking physical activity with clinical, functional, and structural knee osteoarthritis outcomes. Electronic databases were searched until June 2021. Studies from the OAI reporting subjective (Physical Activity Scale for the Elderly, PASE) or objective (accelerometry) physical activity data were included. Scatter plots were created to represent each outcome group (clinical, functional, structural) and physical activity measure (PASE, accelerometry) to map the evidence by the directional effect (positive, interaction, negative, or no effect) associated with physical activity. Forty-two articles were included in this review. Physical activity was quantified using PASE (n = 21), accelerometry (n = 20), or both (n = 1). Studies reported consistently positive physical activity effects on clinical (n = 22) and functional (n = 20) outcomes, with few exceptions. Structural (n = 15) outcomes were largely reported as interaction effects by physical activity intensity or sex, or as no significant effect. A network of interconnected outcomes emerged, with clinical and functional outcomes often reported together, and structural outcomes reported individually. This study provides an overview of current evidence linking physical activity to multiple interrelated knee osteoarthritis outcomes using an OAI-driven model. These evidence maps can be used as a framework to guide future investigations of the effects of physical activity on knee osteoarthritis.

Association of Low Physical Activity Levels With Gait Patterns Considered at Risk for Clinical Knee Osteoarthritis Progression

Objective

Although gait analysis provides an estimate of joint loading magnitude and patterns during a typical step, accelerometry provides information about loading frequency. Understanding the relationships between these components of loading and knee osteoarthritis (OA) progression may improve conservative management, as gait interventions may need to account for physical activity levels or vice versa. The primary objective was to examine relationships between gait patterns that have previously been associated with OA progression and accelerometer‐derived metrics of loading frequency. The secondary objective examined the association of accelerometer‐derived metrics and total knee arthroplasty (TKA) at a mean follow‐up of 3.5 years.

Methods

Fifty‐seven individuals with knee OA underwent gait analysis and 1 week of accelerometer wear. Spearman correlations were calculated between accelerometer‐derived metrics and gait patterns. Differences across quartiles of step count were examined with Jonckheere‐Terpstra tests. In a subsample, baseline differences between TKA and no TKA groups were examined with Mann‐Whitney U‐tests.

Results

Gait variables previously related to progression were correlated to both step count and moderate‐ to vigorous‐intensity, but not lower‐intensity, physical activity. Individuals in the lowest quartile (~4000 steps/day) exhibited gait patterns previously related to progression. There were no differences in any baseline accelerometer‐derived metrics between those that did and did not undergo TKA at follow‐up.

Conclusion

Complex relationships exist between gait, physical activity, and OA progression. Accelerometer‐derived metrics may contribute unique information about overall loading for individuals above a certain activity threshold, but for those with lower activity levels, gait may be sufficient to predict clinical progression risk, at least over the short term.

Association between changes in the knee adduction moment and changes in knee pain and function in response to non-surgical biomechanical interventions for medial knee osteoarthritis: a systematic review

There is lack of understanding of the relationship between knee adduction moment (KAM) reductions and improvements in pain or function in patients with knee osteoarthritis (KOA). Moreover, there is no systematic review describing the longitudinal relationship between KAM changes and subsequent changes in pain and/or physical function. We aimed (1) to investigate the relationship between changes in KAM induced by non-surgical biomechanical interventions and consecutive changes in pain and/or physical function in patients with medial KOA and (2) to compare this relationship for different interventions. We considered eligible all RCTs using biomechanical interventions aimed to reduce KAM in KOA patients, that measured pain/function. We used Cohen's d effect size to quantify outcome measurements. 14 papers reporting 11 studies were identified. Braces were tested in 6 studies, insoles in 5 studies, shoes in 3 studies and gait retraining in 2 studies. Methodological differences were large among studies. Large effect sizes (≥0.8) changes in pain/function were observed with interventions having at least a small KAM effect size (≥0.2), suggesting an association between KAM and pain/function changes. A linear trend was observed between inter-intervention KAM and VAS pain effect sizes, based on 4 studies. No firm conclusions could be drawn for the different intervention types. There was a trend toward larger KAM reductions leading to larger improvements in pain/function in non-surgical biomechanical interventions. Additional high-quality RCT with consistent methodology are needed to fully characterize the association between KAM and pain/function changes.

Exploring the relationship between pain intensity and knee moments in participants with medial knee osteoarthritis: a cross-sectional study

Background

High biomechanical loading is believed to be a risk factor to pain in people with knee osteoarthritis (OA), but controversial findings have been reported on the relationship between external knee adduction moment (KAM) and pain. A more comprehensive analysis considering other factor such as external knee flexion moment (KFM) could help better reveal this relationship. This study explored the relationship between external knee adduction moment and pain intensity in participants with knee osteoarthritis (OA) using an integrated path analysis model.

Methods

This was a cross-sectional study based on laboratory setting. Forty-seven participants with clinical and radiographic medial knee OA were analyzed for their external knee adduction moment (KAM) and knee flexion moment (KFM) during walking using a motion analysis system. Pain intensity was measured by visual analogue scale (VAS) and the pain subscale of the Knee Injury and Osteoarthritis Outcome Score. Varus/valgus alignment was captured and quantified using a bi-planar X-ray system. Using a path analysis model, the relationships between pain intensity, KAM, KFM, OA radiographic severity, knee varus angle and walking speed were examined.

Results

The proposed path model met the goodness-of-fit criteria. Based on this model, KAM had a negative effect on VAS pain indirectly through the mediation of KFM. The model indicated KAM and KFM were negatively related to one another; and KFM was positively related to VAS. The KAM index, defined as (KAM/ (KAM + KFM)), was negatively related to VAS.

Conclusions

Path analysis enabled the construction of a more integrated pathokinematic framework for people with knee OA. The KAM index which reflected the load sharing on the frontal and sagittal planes also revealed its relationship with pain. Re-distribution of mechanical loading from frontal to sagittal plane might be a strategy for pain avoidance associated with mechanical irritation.

Best-practice clinical management of flares in people with osteoarthritis: A scoping review of behavioral, lifestyle and adjunctive treatments

INTRODUCTION

Transient episodes of increased pain, stiffness or swelling are common in people with osteoarthritis (OA). Yet, evidence-based management strategies for lessening the impact of OA flares are rarely covered in clinical guidelines and have been identified as a gap by clinicians delivering OA care. We aimed to identify evidence on behavioral, lifestyle or other adjunctive flare management strategies that could be used by clinicians or consumers.

MATERIALS AND METHODS

A literature search between 1990-2020 was performed in three databases using a scoping methodology. We included qualitative or quantitative studies, and reviews that examined OA flare management, or that reported OA flare outcomes at timepoints ≤2 weeks post-intervention. Outcomes included any physical or psychological OA outcome treatable with a therapeutic intervention.

RESULTS

We included 9 studies, all of which examined the relationship between therapeutic exercise/ physical activity and OA flares. All studies reported pain outcomes at the knee. Two also included the hip. Only two studies examined specific management strategies for OA flares. Both favorably reported the benefits of undertaking an exercise program modified accordingly during an episode, but the quality of the evidence was low.

DISCUSSION

This scoping review highlights the paucity of evidence available on non-pharmacological treatments of OA flare management that could influence clinical practice. At present, there is no robust evidence to support or reject any specific therapies for OA flare management in clinical practice. Future work is needed, particularly around outcomes beyond pain, trajectories of symptom improvement, and for joints other than the knee.

Juvenile idiopathic arthritis, gait characteristics and relation to function

BACKGROUND

Juvenile Idiopathic Arthritis (JIA) is a chronic inflammatory arthritis that impacts biomechanical features of gait. This systematic review describes the effects of JIA on gait motion parameters and walking performance.

METHODS

Six databases were searched (PubMed/Medline, Cochrane, the EBSCOHost database SPORTDiscus, Web of Science, and Embase). Studies were restricted to children with any subtype of JIA who were assessed for gait motion features (kinematic, kinetic, temporalspatial) or walking performance (velocity or distance covered); could include intervention or treatment exposure with measures of gait and gait speed; could involve comparison of gait in JIA to healthy controls. Quality of evidence was assessed using the GRADE system. This systematic review was registered at PROSPERO (CRD42018109582) RESULTS: The search yielded 625 papers, 23 of which described biomechanical features of gait and/or assessed walking performance. Twenty studies measured walking velocity and walking ability using simple field tests or laboratory methods. Eleven studies measured temporalspatial parameters such as cadence, step length, stride length, step width, single and double support time. Nine studies evaluated kinetic measurements including joint power, flexion and extension and joint moments. Nine studies evaluated kinematic parameters including range of motion, pelvic tilt, center of motion and trunk sway.

CONCLUSIONS

Key features of gait in children with JIA include slower gait velocity, shortened step length, decreased range of motion at the hip, knee and ankle with trend towards flexion, decreased joint power, anteriorly tilted pelvis and trunk with shifted center of motion. There is a potential to ameliorate JIA-related gait changes with exercise and/or pharmaceutical interventions.

Osteoarthritis year in review 2019: mechanics

Mechanics play a critical - but not sole - role in the pathogenesis of osteoarthritis, and recent research has highlighted how mechanical constructs are relevant at the cellular, joint, and whole-body level related to osteoarthritis outcomes. This review examined papers from April 2018 to April 2019 that reported on the role of mechanics in osteoarthritis etiology, with a particular emphasis on studies that focused on the interaction between movement and tissue biomechanics with other clinical outcomes relevant to the pathophysiology of osteoarthritis. Studies were grouped by themes that were particularly prevalent from the past year. Results of the search highlighted the large exposure of knee-related research relative to other body areas, as well as studies utilizing laboratory-based motion capture technology. New research from this past year highlighted the important role that rate of exerted loads and rate of muscle force development - rather than simply force capacity (strength) - have in OA etiology and treatment. Further, the role of muscle activation patterns in functional and structural aspects of joint health has received much interest, though findings remain equivocal. Finally, new research has identified potential mechanical outcome measures that may be related to osteoarthritis disease progression. Future research should continue to combine knowledge of mechanics with other relevant research techniques, and to identify mechanical markers of joint health and structural and functional disease progression that are needed to best inform disease prevention, monitoring, and treatment.

Comparison of Physical Activity Measures Derived From the Fitbit Flex and the ActiGraph GT3X+ in an Employee Population With Chronic Knee Symptoms

Objective

We examined the accuracy of data from an affordable personal monitor (Fitbit Flex) compared with that of data from a research‐grade accelerometer worn simultaneously for 7 days; high accuracy would support substitution with this less‐expensive personal activity monitor in future community‐based arthritis research.

Methods

Subjects (N = 35) with chronic knee symptoms were recruited for a pilot intervention study using Fitbits to increase physical activity in employees with chronic knee symptoms at an urban corporation. Subjects simultaneously wore for 7 days a Fitbit Flex (wrist‐worn) and ActiGraph GT3X+ (waist‐worn). Fitbit Flex data were regularly stored on a research storage service (Fitabase) by participants. Bland–Altman plots were constructed to examine the agreement between the mean daily times spent in light activity and in bouted moderate‐to‐vigorous physical activity (MVPA). Comparisons were calculated by matching Fitabase data from calendar days the Fitbit was worn with data from valid monitoring days (greater than or equal to 10 hours wear time) of the ActiGraph.

Results

Participants at baseline were mostly female (69%) and white (57%) and had a mean age of 52 years and body mass index of 32 kg/m². Bland–Altman analyses indicated systematic bias overall (the Fitbit overestimated both light‐intensity activity and MVPA compared with the ActiGraph). The average error varied in magnitude and direction with changing activity amounts.

Conclusion

The Fitbit Flex does not appear to be an adequate substitute for research‐grade accelerometry (which represents the gold standard for objective research monitoring of all physical activity intensity levels) in this population of persons with chronic knee symptoms.