Frontal plane kinematics in walking with moderate hip osteoarthritis: Stability and fall risk

Validity of Linear and Nonlinear Measures of Gait Variability to Characterize Aging Gait with a Single Lower Back Accelerometer

The attractor complexity index (ACI) is a recently developed gait analysis tool based on nonlinear dynamics. This study assesses ACI's sensitivity to attentional demands in gait control and its potential for characterizing age-related changes in gait patterns. Furthermore, we compare ACI with classical gait metrics to determine its efficacy relative to established methods. A 4 × 200 m indoor walking test with a triaxial accelerometer attached to the lower back was used to compare gait patterns of younger (N = 42) and older adults (N = 60) during normal and metronome walking. The other linear and non-linear gait metrics were movement intensity, gait regularity, local dynamic stability (maximal Lyapunov exponents), and scaling exponent (detrended fluctuation analysis). In contrast to other gait metrics, ACI demonstrated a specific sensitivity to metronome walking, with both young and old participants exhibiting altered stride interval correlations. Furthermore, there was a significant difference between the young and old groups (standardized effect size: -0.77). Additionally, older participants exhibited slower walking speeds, a reduced movement intensity, and a lower gait regularity. The ACI is likely a sensitive marker for attentional load and can effectively discriminate age-related changes in gait patterns. Its ease of measurement makes it a promising tool for gait analysis in unsupervised (free-living) conditions.

Three-dimensional analysis of locomotion patterns after hindlimb suspension and subsequent long-term reloading in growing rats

The long-term effects of insufficient weight loading during growth on locomotion patterns are not fully understood. The purpose of this study was to determine 1) the effects of hindlimb suspension (HS) in skeletally immature rats on locomotion patterns using a treadmill and a three-dimensional (3D) motion analysis system, and 2) the relationships between locomotion patterns and femoral morphologies, which were reconstructed from 3D computed tomography images taken at 54 weeks old. Four-week-old female rats were subjected to HS four or eight weeks, followed by reloading for until reaching up to 54 weeks old. Age-matched untreated rats served as controls. Motion analysis revealed that four and/or eight weeks of HS resulted in increased pelvis oscillation in the frontal plane during steps, decreased hip adduction angle, and toe-out (increased foot abduction angle) during the load response phase at one and five weeks after reloading. Interestingly, the decreased hip adduction angle and toe-out induced by eight weeks of HS persisted even at 54 weeks old. Pearson's correlation analysis revealed a strong relationship between the hip adduction angle and femoral anteversion angle (r = -0.78) and a moderate relationship between the medial/lateral condyle height (an index of asymmetric condyle size) and toe-out angle (r = 0.66). These results suggest that insufficient weight loading during growth may induce abnormal locomotion patterns via abnormal femoral morphologies that may persist over time.

Feasibility of a new bicycle ergometer with adjustable pedaling configuration for personalized lower limb rehabilitation

Muscle atrophy due to prolonged immobilization leads to severe dysfunction and progression of disease and injury. This highlights the necessity for early rehabilitation, even during the non-ambulatory stages. As manifestations vary among individuals, target-specific rehabilitation is crucial for achieving optimal outcomes. Conventional bicycle ergometers, despite their wide usage in rehabilitation and sports training, fail to adequately recruit the muscles that predominantly operate in the coronal or axial plane. This is thought to be due to the restriction of pedaling trajectory in the sagittal plane. This study introduces a new bicycle ergometer capable of tilting the pedaling plane and adjusting the pedal orientation, in order to alter muscle recruitment patterns and limb alignments. A biomechanical analysis of eight healthy volunteers suggests that our device can elicit dynamic valgus/varus alignment and alter the axial rotations of the lower extremities. An electromyography analysis revealed a significant increase in the activation of specific muscle groups, particularly the abductors and adductors, suggesting promising results for targeted muscle recruitment. We expect this ergometer to provide a new method for target-specific rehabilitation and the treatment of bedridden patients or those with weak muscles.

Gait Compensation among Children with Non-Operative Legg-Calvé-Perthes Disease: A Systematic Review

Perthes disease is a condition that affects walking patterns in young children due to poor blood circulation in the hip joint. Understanding the gait strategies of affected children is of great importance for an objective assessment and better management of this condition. The aim of this systematic review was to evaluate the current literature to identify gait compensation patterns in non-operative children with Perthes disease.

METHODS

A systematic electronic search was performed using MEDLINE, CINAHL, Embase, BIOSIS, and the Cochrane Library to identify studies published from inception up until December 2023. An adapted Downs and Black checklist was utilised to assess methodological quality and project risk of bias. Percentage agreement and nominal kappa statistics with bootstrapped bias-corrected 95% confidence intervals (CIs) were used.

RESULT

A comprehensive literature search revealed 277 citations for review, of which 210 studies entered full-text screening. In total, eight studies met the inclusion criteria for quality assessment by two independent reviewers. The results revealed variations in data quality, with scores ranging from 12 to 17 due to missing information related to subject characteristics, biomechanical model, and power calculation.

CONCLUSIONS

This review reveals common compensation strategies associated with walking among non-operative children with Perthes disease such as Trendelenburg gait due to weakness of the hip abductor muscle.

The relationship between the local dynamic stability of gait to cognitive and physical performance in older adults: A scoping review

BACKGROUND

Local dynamic stability (LDS) has become accepted as a gait stability indicator. The deterioration of gait stability is magnified in older adults.

RESEARCH QUESTION

What is the current state in the field regarding rthe relationship between LDS and cognitive and/or physical function in older adults?

METHODS

A scoping review design was used to search for peer-reviewed literature or conference proceedings published through May 2023 for an association between LDS and cognitive (e.g., Montreal Cognitive Assessment) or physical performance (e.g., Timed Up & Go Test) in older adults. Only studies investigating gait stability via LDS during controlled walking, when dealing with a subject group consisting of healthy older adults, and quantifying LDS relationship to cognitive and/or physical measure were included. We analysed data from the studies in a descriptive manner.

RESULTS

In total, 814 potentially relevant articles were selected, of which 15 met the inclusion criteria. We identified 37 LDS quantifiers employed in LDS-cognition and/or LDS-physical performance relationship assessment. Nine measures of cognitive and 20 measures of physical performance were analysed. Most studies estimated LDS quantities using triaxial acceleration data. However, there was a variance in sensor placement and signal direction. Out of the 56 studied relationships of LDS to physical performance measures, sixteen were found to be relevant. Out of 22 studied relationships between LDS and cognitive measures, only two were worthwhile.

SIGNIFICANCE

Considering the heterogeneity of the utilized LDS (caused by different sensors locations, signals, and signal directions as well as variety of computational approaches to estimate LDS) and cognitive/physical measures, the results of this scoping review does not indicate a current need for a systematic review with meta-analysis. To assess the overall utility of LDS to reveal a relationship between LDS to cognitive and physical performance measures, an analysis of other subject groups would be appropriate.

Avascular Necrosis of the Hip Compromises Gait Balance Control in Female Juveniles With Unilateral Developmental Dysplasia Treated in Toddlerhood

Avascular necrosis of the hip (AVN) is one of the most severe complications of surgical reduction when treating developmental dysplasia of the hip (DDH). The current study identified the differences in the balance control during walking in terms of the inclination angle (IA) of the center of pressure (COP) to the center of mass (COM), and the rate of change of IA (RCIA) between female juveniles with and without secondary AVN at the hip who were treated for unilateral DDH during toddlerhood as compared to their healthy peers. When compared to female healthy controls, the non-AVN group showed bilaterally similar compromised balance control with significantly decreased IA (p < 0.05) but increased RCIA (p < 0.04) in the sagittal plane during single-limb support (SLS) of the unaffected side, and in the frontal plane during terminal double-limb support (DLS) of the affected side. In contrast, the AVN increased between-side differences in the sagittal IA (p = 0.01), and sagittal and frontal RCIA during DLS (p < 0.04), leading to bilaterally asymmetrical balance control. Secondary AVN significantly reduced IA and RCIA in the sagittal plane (p < 0.05), and reduced range of RCIA in the frontal plane during initial DLS (p < 0.05). The trend reversed during terminal DLS, indicating a conservative COM-COP control in the sagittal plane and a compromised control in the frontal plane during body weight acceptance, with a compromised COM-COP control in the frontal plane during weight release. The current results suggest that increased between-side differences in the sagittal IA, and sagittal and frontal RCIA during DLS are a sign of AVN secondary to treated unilateral DDH in female juveniles, and should be monitored regularly for early identification of the disease.

Strong relationship of muscle force and fall efficacy, but not of gait kinematics, with number of falls in the year after Total Hip Arthroplasty for osteoarthritis: An exploratory study

BACKGROUND

In people with moderate hip osteoarthritis, gait kinematics was reported to be correlated with number of falls in the preceding year. After Total Hip Arthroplasty, subjects generally improve but still fall. The present study explores recovery and correlations with number of falls in the year after Total Hip Arthroplasty.

METHODS

We assessed 12 patients one year after Total Hip Arthroplasty, 12 patients with moderate hip osteoarthritis with at least one fall in the preceding year, and 12 healthy peers. Maximum hip abduction strength, Fall Efficacy Scale - International, Harris Hip Score, pain, and number of falls in the preceding year were assessed. Participants walked on a treadmill with increasing speeds, and gait kinematics were registered optoelectronically. We assessed group differences, and correlations of all variables with number of falls.

FINDINGS

After arthroplasty, subjects tended to score better on variables measured, often non-significantly, compared to subjects with moderate osteoarthritis, but worse than healthy peers. Maximum hip abduction strength together with fall efficacy had a strong regression on the number of falls in the preceding year (R² = 92%). Gait kinematics did not correlate with number of falls, and also fall efficacy was not related to gait kinematics.

INTERPRETATION

One year after hip arthroplasty, muscle strength sufficiently recovered for normal walking, but not to avoid falling in risky situations. Rehabilitation should focus on muscle strength. The lack of correlation between the Fall Efficacy International and gait kinematics, suggests that it reflected the experience of having fallen rather than fear.

Musculoskeletal pain in Parkinson's disease: a narrative review

The prevalence of musculoskeletal (MSK) pain in people with Parkinson's disease (PD) is higher than that of age-matched controls. In this review, we outline what is known about MSK pain in PD, focusing on the neck, shoulder, knee, hip and low back. We also compare what is known about MSK pain in PD to what is known in older adults without PD. Finally, we outline areas of for future research related to MSK pain in people with PD.

Association between hip and knee osteoarthritis with falls: A systematic review and meta-analysis

OBJECTIVE

To examine the association between hip and knee osteoarthritis (OA) and falls. Potentially relevant articles that examine the association between hip, knee, radiological, and self-reported OA and falls were retrieved from PubMed, EMBASE, Scopus, and Web of Science up until March of 2020.

METHODS

The pooled risk ratios (RRs) as well as their related 95% confidence intervals (CIs) were calculated. Statistic and subgroup analyses were performed. A total of 21 studies involving 146 965 participants were included.

RESULTS

No association was found between hip OA and falls. The pooled RRs value suggested a higher prevalence of falls in knee OA patients (RR = 1.35, 95% CI: 1.20 to 1.51, P < .00001) and self-reported OA (RR = 1.33, 95% CI: 1.23 to 1.45, P < .00001) than in non-OA subjects. The pooled RR value suggested no difference between prevalence of falls in radiological OA patients compared to non-OA subjects (RR = 1.82, 95% CI: 0.89 to 3.73, P = .10). Both radiological and self-reported knee OA seem to be positively associated with falls, while no obvious association was found between hip OA and falls.

CONCLUSIONS

Therefore, knee OA is a risk factor for falls which should be closely monitored.

Movement quality evaluation and its correlation with recommended functional measures in hip osteoarthritis

OBJECTIVE

Hip osteoarthritis may cause compensational movement strategies that require extra physical and mental effort. Such aberrant functioning can be captured in movement quality evaluation. The objective of this study was to explore whether movement quality, evaluated as a multiperspective phenomenon, is reflected in commonly used and recommended functional measures in this group of patients.

METHODS

A cross-sectional study design was used. Baseline included 80 female and 21 male participants with hip osteoarthritis. Movement quality was evaluated by the Body Awareness Rating Scale-Movement Quality and Experience (BARS-MQE), part one, including 12 movement items. Correlation analyses (Pearson and Spearman) were performed to explore associations between BARS-MQE (sum score and single item scores), and scores on measures of physical capacity (Chair test, Stairs test, 6 minutes walking test; 6MWT), self-reported activity level (UCLA), function (HOOS subscales), pain during walking (NRS), self-efficacy (ASES) and health (EQ-5D-5L). Based on previous evidence, we hypothesized moderate associations between BARS-MQE and these measures.

RESULTS

BARS-MQE's sum score showed moderate associations with Stairs test, 6MWT and UCLA (r = -0.425 to 0.304) and weak associations (r = 0.29 to 0.12) with ASES Pain and Symptoms, HOOS ADL, Chair test, NRS, HOOS Pain and Sports, and EQ-5D-5L. No association was found between BARS-MQE and HOOS Symptoms and Quality of life. Movement quality in item 12, walking, demonstrated moderate or weak association with all included measures.

CONCLUSION

In this study of participants diagnosed with hip osteoarthritis, movement quality evaluated by BARS-MQE was moderately reflected in measures of physical capacity and activity, but weakly reflected in self-reported measures of health problems. With its particular dynamic procedure and inclusion of the whole moving person, movement quality evaluation by the BARS-MQE was shown to provide supplementary information on functioning, scarcely captured by the commonly used and recommended measures.

Descriptions of movement experiences in the Body Awareness Rating Scale - Movement Quality and Experience evaluation. A qualitative study of patients diagnosed with hip osteoarthritis

Background: Patients' access to movement experiences is implemented in the evaluation tool Body Awareness Rating Scale - Movement Quality and Experience, with its two intertwined parts: 1) the physiotherapist's observations of movement quality; and 2) the patient's descriptions of immediate movement experiences.Objective: To study movement experiences and reflections described by patients diagnosed with hip osteoarthritis when guided to explore simple daily-life movements in this particular evaluation context.Design: An explorative qualitative study with open-ended questions following each of the 12 movements integrated into the evaluation.Methods: 35 participants diagnosed with hip osteoarthritis were included; 28 women and 7 men, aged 23-78 years. Their descriptions were audiotaped, transcribed verbatim and analyzed in accordance with qualitative content analysis.Results: The patients described experiences of a dynamic adaptation of movement strategies based on sensations from the moving body. Two interrelated categories of movement awareness were identified: 1) Experienced movement challenges, including three sub-categories; a) Lack of contact, b) Movement changed by symptoms, and c) Compensational movement habits, and 2) Movement components promoting well-being, including three sub-categories; a) Integrating balance, breathing and awareness into movement, b) Small, simple, soft and safe movements, and c) A taste of own movement resources for daily life.Conclusions: The Body Awareness Rating Scale - Movement Quality and Experience provides a platform for patients to become aware of and describe their movement habits and resources in own words, intertwined with the physiotherapist movement observations. Derived descriptions reflect a patient perspective to be implemented in therapy.

Proactive Locomotor Adjustments Are Specific to Perturbation Uncertainty in Below-Knee Prosthesis Users

Sensory-motor deficits associated with below-knee amputation impair reactions to external perturbations. As such, below-knee prosthesis users rely on proactive control strategies to maintain locomotor stability. However, there are trade-offs (metabolic, comfort, etc.) associated with proactive strategies. We hypothesize that because proactive control strategies are costly, prosthesis users and non-impaired participants will use a priori knowledge (timing, direction) of an impending lateral perturbation to make specific gait adaptations only when the timing of the perturbation is known and the adaptation can be temporally-limited. This hypothesis was partially supported. When the perturbation timing was predictable, only prosthesis users, and only on their impaired side, increased their lateral margin of stability during the steps immediately preceding the perturbation when perturbation direction was either unknown or known to be directed towards their impaired side. This strategy should reduce the likelihood of requiring a corrective step to maintain stability. However, neither group exhibited substantial proactive adaptations compared to baseline walking when perturbation timing was unpredictable, independent of perturbation direction knowledge. The absence of further proactive stabilization behaviors observed in prosthesis users in anticipation of a certain but temporally unpredictable perturbation may be partially responsible for impaired balance control.

Gait variability and motor control in patients with knee osteoarthritis as measured by the uncontrolled manifold technique

Knee osteoarthritis (OA) causes pain, reduced muscular strength and stiffness of the affected joint. In response, the motor control mechanism is altered, potentially compromising stability during acts of daily living. Reduced walking stability can be quantified in terms of gait variability. This study therefore aimed to identify and quantify the effects of knee arthritis on gait variability. Fifty adults (25 males/25 females) with end-stage OA of the knee sufficiently symptomatic to require joint replacement, walked on a self-paced treadmill for 2min. A motion capture system was used to record 50 consecutive gait cycles from each patient. Kinematic variability of gait was analysed using the uncontrolled manifold technique (UCM). The position of the centre of mass (COM) was chosen as the task variable for the analysis. Results showed that our patient cohort were able to maintain a stable COM whilst walking, through adopting variable combinations of hip, knee and ankle kinematics. The greatest magnitudes of instability (based on the UCM ratios) occurred during initial contact and terminal stance. Active extension of the knee joint to approximately 5° is required during these gait cycle events, meaning that these gait events are highly quadriceps dependent. This study identified and quantified components of the gait cycle where patients with knee OA are most unstable. Employment of this technique could therefore allow specific personalised prescription for prehabilitation and rehabilitation.

Root mean square of lower trunk acceleration during walking in patients with unilateral total hip replacement

Although several studies have described abnormal trunk motion before and after total hip arthroplasty (THA) surgery, few studies have examined trunk motion using accelerometry. The aim of this study was to determine whether abnormal trunk motion persisted after THA using accelerometry. A total of 24 female patients (61.0±6.9years) and 20 healthy female subjects (59.9±6.8years) participated in this study. Patients were assessed at 1 month prior to surgery and 12 months after surgery. Trunk acceleration during gait was measured using a triaxial accelerometer attached to the L3 spinous process. We calculated the root mean square (RMS) and RMS ratio (RMSR) in the vertical (VT), medio-lateral (ML), and anterior-posterior (AP) directions. Results revealed that the RMS in the VT and AP directions postoperatively was greater than that preoperatively, whereas there was no difference in the RMS in the ML direction. In addition, the preoperative RMSR in the ML direction was significantly greater compared with that of healthy individuals and the postoperative RMSR. There was no difference in the RMSR in the ML direction between healthy individuals and postoperatively. These findings suggested that the trunk motion in the frontal plane prior to surgery had improved and was comparable to that of healthy individuals following THA.

Dynamic feet distance: A new functional assessment during treadmill locomotion in normal and thoracic spinal cord injured rats

Of all the detrimental effects of spinal cord injury (SCI), one of the most devastating is the disruption of the ability to perform functional movement. Very little is known on the recovery of hindlimb joint kinematics after clinically-relevant contusive thoracic lesion in experimental animal models. A new functional assessment instrument, the dynamic feet distance (DFD) was used to describe the distance between the two feet throughout the gait cycle in normal and affected rodents. The purpose of this investigation was the evaluation and characterization of the DFD during treadmill locomotion in normal and T9 contusion injured rats, using three-dimensional (3D) instrumented gait analysis. Despite that normal and injured rats showed a similar pattern in the fifth metatarsal head joints distance excursion, we found a significantly wider distance between the feet during the entire gait cycle following spinal injury. This is the first study to quantify the distance between the two feet, throughout the gait cycle, and the biomechanical adjustments made between limbs in laboratory rodents after nervous system injury.

Development of a rapid stepping test to challenge rapid weight-shifting function in older adults

BACKGROUND

The ability to step rapidly, shift weight from side-to-side, and maintain temporal rhythmicity are important functional elements for walking independently and preventing falls in seniors.

AIMS

The purpose of this study was to develop a clinically feasible test of rapid stepping performance that challenges the ability to step rapidly, shift weight from side-to-side, and maintain temporal rhythmicity.

METHODS

Participants were a volunteer sample of healthy, self-ambulating older adults aged 70-98 years. A Repeated Alternating Stair Touch Test was developed, which involved rapidly shifting weight in the medial-lateral direction by tapping each foot alternately onto a step. Performance on the test was assessed using trunk acceleration signals. Associations between the number of steps completed on the Repeated Alternating Stair Touch Test in 20 s and acceleration magnitude, variability, and stepping rhythmicity were assessed using Pearson correlations and linear regression. Repeatability was assessed during a 2-week follow-up period.

RESULTS

The acceleration magnitude, variability, and stepping rhythmicity variables related moderately with the number of steps on the Repeated Alternating Stair Touch Test (r = 0.534-0.572, p < 0.05) and were independent predictors of the number of steps taken (R ² adj. = 0.624, p < 0.001). Repeatability was mixed, though most acceleration variables and number of steps had moderate to high correlations between sessions (intraclass correlations: 0.486-0.828), but a learning effect was evident; performance improved between sessions.

CONCLUSION

The Repeated Alternating Stair Touch Test has potential as a simple test of rapid, rhythmic weight-shifting function, but requires modification to improve repeatability.

Osteoarthritis year in review 2016: mechanics

Inappropriate biomechanics, namely wear-and-tear, has been long believed to be a main cause of osteoarthritis (OA). However, this view is now being re-evaluated, especially when examined alongside mechanobiology and new biomechanical studies. These are multiscale experimental and computational studies focussing on cell- and tissue-level mechanobiology through to organ- and whole-body-level biomechanics, which focuses on the biomechanical and biochemical environment of the joint tissues. This review examined papers from April 2015 to April 2016, with a focus on multiscale experimental and computational biomechanical studies of OA. Assessing the onset or progression of OA at organ- and whole-body-levels, gait analysis, medical imaging and neuromusculoskeletal modelling revealed the extent to which tissue damage changes the view of inappropriate biomechanics. Traditional gait analyses studies reported that conservative treatments can alter joint biomechanics, thereby improving pain and function experienced by those with OA. Results of animal models of OA were consistent with these human studies, showing interactions among bone, cartilage and meniscus biomechanics and the onset and/or progression OA. Going down size scales, experimental and computational studies probed the nanosize biomechanics of molecules, cells and extracellular matrix, and demonstrated how the interactions between biomechanics and morphology affect cartilage dynamic poroelastic behaviour and pathways to OA. Finally, integration of multiscale experimental data and computational models were proposed to predict cartilage extracellular matrix remodelling and the development of OA. Summarising, experimental and computational methods provided a nuanced biomechanical understanding of the sub-cellular, cellular, tissue, organ and whole-body mechanisms involved in OA.

Is the instrumented-pointer method of calibrating anatomical landmarks in 3D motion analysis reliable?

Instrumented-pointers are often used to calibrate anatomical landmarks in biomechanical analyses. However, little is known about the effect of altering the orientation of the pointer during calibration on the co-ordinates recorded. Incorrect positioning of a landmark influences the axes created, and thus the kinematic data recorded. This study aimed to investigate the reliability of the pointer method for anatomical calibration. Two points were drawn onto a fixed box to resemble knee joint epicondyles, then a custom-made pointer was used to define the positions of these landmarks in three-dimensions. Twenty different pointer-orientations were chosen, and the position of the pointer in each of these orientations was recorded 8 times. Euclidean distances between single points were calculated for both landmarks and compared statistically (α = 0.05). Average Euclidean distances between all reconstructed points were 3.2±1.4mm (range: 0.3-7.1mm) for one landmark and 3.3±1.5mm (range: 0.3-7.9mm) for the other. The x- and y-co-ordinates recorded differed statistically when the pointer was moved about the X and Y axes (anterior/posterior and superior/inferior to landmark) (p < 0.05). No statistical differences were found between co-ordinates recorded when the pointer was moved around the Z axes (p > 0.05). ICC values for all co-ordinates were excellent, highlighting the reliability of the method (ICC > 0.90). These results support this method of anatomical calibration; however, we recommend that pointers be consistently held in a neutral oriented position (where the handle is not anterior, posterior, superior or inferior to the landmark) during calibration, to reduce the likelihood of calibration errors.

Restricted Arm Swing Affects Gait Stability and Increased Walking Speed Alters Trunk Movements in Children with Cerebral Palsy

Observational research suggests that in children with cerebral palsy, the altered arm swing is linked to instability during walking. Therefore, the current study investigates whether children with cerebral palsy use their arms more than typically developing children, to enhance gait stability. Evidence also suggests an influence of walking speed on gait stability. Moreover, previous research highlighted a link between walking speed and arm swing. Hence, the experiment aimed to explore differences between typically developing children and children with cerebral palsy taking into account the combined influence of restricting arm swing and increasing walking speed on gait stability. Spatiotemporal gait characteristics, trunk movement parameters and margins of stability were obtained using three dimensional gait analysis to assess gait stability of 26 children with cerebral palsy and 24 typically developing children. Four walking conditions were evaluated: (i) free arm swing and preferred walking speed; (ii) restricted arm swing and preferred walking speed; (iii) free arm swing and high walking speed; and (iv) restricted arm swing and high walking speed. Double support time and trunk acceleration variability increased more when arm swing was restricted in children with bilateral cerebral palsy compared to typically developing children and children with unilateral cerebral palsy. Trunk sway velocity increased more when walking speed was increased in children with unilateral cerebral palsy compared to children with bilateral cerebral palsy and typically developing children and in children with bilateral cerebral palsy compared to typically developing children. Trunk sway velocity increased more when both arm swing was restricted and walking speed was increased in children with bilateral cerebral palsy compared to typically developing children. It is proposed that facilitating arm swing during gait rehabilitation can improve gait stability and decrease trunk movements in children with cerebral palsy. The current results thereby partly support the suggestion that facilitating arm swing in specific situations possibly enhances safety and reduces the risk of falling in children with cerebral palsy.

Kinematic gait patterns and their relationship to pain in mild-to-moderate hip osteoarthritis

BACKGROUND

Mild-to-moderate hip osteoarthritis is often managed clinically in a non-surgical manner. Effective non-surgical management of this population requires characterizing the specific impairments within this group. To date, a complete description of all lower extremity kinematics in mild-to-moderate hip osteoarthritis patients has not been presented. The aim of the present study is to describe the lower extremity gait kinematics in mild-to-moderate hip osteoarthritis patients and explore the relationship between kinematics and pain.

METHODS

22 subjects with mild-to-moderate radiographic hip osteoarthritis (Kellgren-Lawrence grade 2-3) and 22 healthy age and BMI matched control subjects participated. Kinematic treadmill walking data were collected across all lower extremity joints. A two-way repeated measures analysis of variance estimated mean differences in gait kinematics between groups. Correlations between gait kinematics and pain were assessed using a Spearman correlation coefficient.

FINDINGS

Hip osteoarthritis subjects hiked their unsupported hemi-pelvis 1.40° (P<0.001) more than controls and tilted their pelvis 4.65° more anteriorly (P=0.01). Osteoarthritis subjects walked with 4.30° more peak hip abduction (P<0.001), 8.57° less peak hip extension (P<0.001), and 10.54° more peak hip external rotation (P<0.001). Kinematics were related to pain in the ankle frontal plane only (r=-0.43, P<0.05).

INTERPRETATION

Individuals with mild-to-moderate hip osteoarthritis demonstrate altered gait biomechanics not related to pain. These altered biomechanics may represent effective therapeutic targets by clinicians working with this population. Understanding the underlying patho-anatomic changes that lead to these biomechanical changes requires further investigation.