Clinical Biomechanics最新文献

Background

The impact of lower-limb-lymphedema on quality of life of patients regarding balance is unclear due to the scarcity of literature. The aim of this study was to determine the static and dynamic balance of patients with lower-limb-lymphedema in comparison with healthy subjects.

Methods

This case-control designed study included 30 lymphedema patients and 30 healthy individuals, of whom were 52 female and 8 male with a mean age of 50.63 ± 9.72 years. Static balance stability and anterior-posterior with lateral sway parameters on four conditions (eyes-opened-stable-ground, eyes-closed-stable-ground, eyes-opened-unstable-ground, eyes-closed-unstable-ground) and dynamic stability of all participants were evaluated.

Findings

The demographic variables were similar between the groups. Majority of the patients had lymphedema due to cancer surgery with a stage of 2. Dynamic stability was significantly disrupted in lymphedema group in comparison with controls (P = 0.049). Static balance parameters were impaired on all conditions except the eyes opened-stable ground in lymphedema patients (P = 0.048,P = 0.043,P = 0.017). The dynamic with static balance and lateral sway parameters were correlated with the duration of lymphedema(P = 0.046,P = 0.002,P = 0.005). Anterior-posterior sway on eyes-closed-unstable-ground condition was correlated with functional status (P = 0.02). Static balance on eyes-opened-unstable-ground condition and anterior-posterior sway parameters were correlated with physical activity level (P = 0.015,P = 0.016,P < 0.05).

Interpretation

Closing eyes and the deterioration of ground caused significant alteration of the static and dynamic balance both separately and together in patients with lower-limb-lymphedema compared to healthy subjects. Regarding the static and dynamic imbalance, we suggest the evaluation of balance and inclusion of balance exercises in routine lymphedema rehabilitation program, especially in the early period of disease.

Background

Rupturing the anterior cruciate ligament is an orthopedic injury that results in neuromuscular impairments affecting sensory input to the central nervous system. Traditional physical therapy after anterior cruciate ligament reconstruction aims to rehabilitate orthopedic impairments but fails to address asymmetric gait mechanics that are present post-operatively and are linked to the development of post-traumatic osteoarthritis. A first step towards developing gait interventions is understanding if individuals after anterior cruciate ligament reconstruction have the capacity to learn new walking mechanics.

Methods

The split-belt treadmill offers a task-specific approach to examine neuromuscular adaptations in patients after injury. The potential for changing spatiotemporal gait mechanics via split-belt treadmill adaptation has not been tested early after anterior cruciate ligament reconstruction; nor has the ability to retain and transfer newly learned gait mechanics. Therefore, we used a split-belt treadmill paradigm to compare gait adaptation, retention, and transfer to overground walking between 15 individuals 3–9 months after anterior cruciate ligament reconstruction and 15 matched control individuals.

Findings

Results suggested individuals after anterior cruciate ligament reconstruction were able to adapt and retain step length symmetry changes as well as controls. There was also evidence of partial transfer to overground walking, similar to controls.

Interpretation

Despite disruption in afferent feedback from the joint, individuals early after anterior cruciate ligament reconstruction can learn a new gait pattern using sensorimotor adaptation, retain, and partially transfer the learned gait pattern. This may be a critical time to intervene with gait-specific interventions targeting post-operative gait asymmetries.

Background

Individuals with a recent anterior cruciate ligament reconstruction may demonstrate an altered movement strategy for protecting the knee and maintaining stability. Altered knee movement might lead to abnormal intra-articular load, potentially contributing to early knee osteoarthritis onset. A protective strategy may be particularly evident during active tasks that induce a pivot-shift manoeuvre, such as a step-down and cross-over task. In this study, we investigated whether knee joint mechanics and muscle activity differed between participants early (∼3 months) following reconstruction (n = 35) to uninjured controls (n = 35) during a step-down and cross-over task with a 45° change-of-direction.

Methods

We used motion capture, force plates and surface electromyography to compare time-normalised curves of sagittal and transverse-plane knee mechanics and muscle activity during the cross-over phase between groups using functional t-tests. We also compared knee mechanics between sides within the injured group and compared discrete outcomes describing the cross-over phase between groups.

Findings

Compared to controls, the injured participants had greater knee flexion angle and moment, lower internal rotation moment, more preparatory foot rotation of the pivoting leg, a smaller cross-over angle, and a longer cross-over phase for both the injured and uninjured sides. The injured leg also had greater biceps femoris and vastus medialis muscle activity compared to controls and different knee mechanics than the uninjured leg.

Interpretation

Individuals with anterior cruciate ligament reconstruction showed a knee-stabilising and pivot-shift avoidance strategy for both legs early in rehabilitation. These results may reflect an altered motor representation and motivate considerations early in rehabilitation.

Background

This study investigated the most accurate method for estimating the hip joint center position in clinical 3D gait analysis for young individuals with high amounts of soft tissue. We compared position estimates of five regression-based and two functional methods to the hip joint center position obtained through 3D free-hand ultrasound.

Methods

For this purpose, the data of 14 overweight or obese individuals with a mean age of 13.6 (SD 2.1 yrs) and a BMI of 36.5 (SD 7.1 kg/m², range 26–52 kg/m²) who underwent standard clinical 3D gait analysis were used. The data of each participant were processed with five regression-based and two functional methods and compared to the hip joint center identified via 3D free-hand ultrasound.

Findings

The absolute location errors to 3D free-hand ultrasound for each anatomical plane and the Euclidean distances served as outcomes next to their effects on gait variables. The data suggest that regression-based methods are preferable to functional methods in this population, as the latter demonstrated the highest variability in accuracy with large errors for some individuals.

Interpretation

Based on our findings we recommend using the regression method presented by Hara et al. due to its superior overall accuracy of <9 mm on average in all planes and the lowest impact on kinematic and kinetic output variables. We do not recommend using the Harrington equations (single and multiple) in populations with high amounts of soft tissue as they require pelvic depth as input, which can be massively biased when a lot of soft tissue is present around the pelvis.

Background

Lung resection is the standard of care for patients with clinical stage I/II non-small cell lung cancer. This surgery reduces both the duration and quality of patients' daily ambulatory activities 1 month after surgery. However, little is known about physical activity after lung resection in patients with lung cancer. To evaluate the recovery process of physical activity with pulmonary rehabilitation in patients after lung resection and examine whether physical activity is affected by age.

Methods

In this prospective, observational study, we measured and analysed participants' postoperative physical activity using a uniaxial accelerometer daily from postoperative day 1 to 30.

Findings

We analysed 99 patients who underwent thoracic surgery. The number of walking steps significantly increased until day 4 and then reached a plateau thereafter. The duration of exercise at <3 metabolic equivalents significantly increased until day 3, and no significant difference was observed thereafter. Exercise at >3 metabolic equivalents significantly increased until day 4 and reached a plateau thereafter. A significant correlation was observed between age and number of steps after day 4. Compared with video-assisted thoracoscopic surgery, thoracotomy significantly decreased the number of steps from day 3 to 4.

Interpretation

We found that the level of physical activity varied by index in patients with non-small cell lung cancer who underwent lung resection. Age and surgical procedure affect different periods with the increase in post-operative walking steps.

Background

Instrumented measurements of postural control provide a more accurate insight into the motor development of children with autism. This study aimed to identify postural control deficits in autistic children during quiet standing before and after transient locomotor task. It was hypothesized that the parameters that characterize the trajectory of center of foot pressure (COP) displacement would be higher in autistic children compared to typically developing children.

Methods

Sixteen autistic children aged 6–10 but without a comorbidity diagnosis, were enrolled in the study group. The control group comprised 16 typically developing peers.

The assessment of the transitional task comprised four different conditions: unperturbed and perturbed transition, stepping up, and stepping down tasks. Analysis of the COP signal was carried out for three distinct phases, i.e., phase 1 – quiet standing before step initiation, phase 2 – transit, and phase 3 - quiet standing until measurement completion.

Findings

The two-way ANOVA with a 2 × 4 factorial design (group × testing condition) revealed a group effect on all posturographic variables in the antero-posterior and medio-lateral directions of phase 1 and in the antero-posterior direction of phase 3. The Bonferroni post-hoc test showed the means of all those variables were significantly higher for the autistic than for typically developing children. Group allocation also had an effect on the time of transit and step length, which turned out to be significantly longer in autistic children compared to healthy peers.

Interpretation

Autistic children show increased postural sway before and after transitional locomotor tasks compared to typically developing children.

The trial was prospectively registered in the Australian and New Zealand Clinical Trials Registry (no. ACTRN12621001113842; date registered: 23.08.2021).

Background

Lower limb amputation does not affect only physical and psychological functioning but the use of a prosthetic device can also lead to increased cognitive demands. Measuring cognitive load objectively is challenging, and therefore, most studies use questionnaires that are easy to apply but can suffer from subjective bias. Motivated by this, the present study investigated whether a mobile eye tracker can be used to objectively measure cognitive load by monitoring gaze behavior during a set of motor tasks.

Methods

Five prosthetic users and eight able-bodied controls participated in this study. Eye tracking data and kinematics were recorded during a set of motor tasks (level ground walking, walking on uneven terrain, obstacle avoidance, stairs up and ramp down, as well as ramp up and stairs down) while the participants were asked to focus their gaze on a visual target for as long as possible. Target fixation times and increase in pupil diameters were determined and correlated to subjective ratings of cognitive load.

Findings

Overall, target fixation time and pupil diameter showed strong negative and positive correlations, respectively, to the subjective rating of cognitive load in the able-bodied controls (−0.75 and 0.80, respectively). However, the individual correlation strength, and in some cases, even the sign, was different across participants. A similar trend could be observed in prosthetic users.

Interpretation

The results of this study showed that a mobile eye tracker may be used to estimate cognitive load in prosthesis users during locomotor tasks. This paves the way to establish a new approach to assessing cognitive load, which is objective and yet practical and simple to administer. Nevertheless, future studies should corroborate these results by comparing them to other objective measures as well as focus on translating the proposed approach outside of a laboratory.

Background

Knowing the mechanical properties of trabecular bone is critical for many branches of orthopaedic research. Trabecular bone is anisotropic and the principal trabecular direction is usually aligned with the load it transmits. It is therefore critical that the mechanical properties are measured as close as possible to this direction, which is often perpendicular to a curved articulating surface. Methods: This study presents a method to extract trabecular bone cores perpendicular to a curved articulating surface of the distal femur. Cutting guides were generated from computed tomography scans of 12 human distal femora and a series of cutting tools were used to release cylindrical bone cores from the femora. The bone cores were then measured to identify the angle between the bone core axis and the principal trabecular axis.

Findings

The method yielded an 83% success rate in core extraction over 10 core locations per distal femur specimen. In the condyles, 97% of extracted cores were aligned with the principal trabecular direction.

Interpretation

This method is a reliable way of extracting trabecular bone specimens perpendicular to a curved articular surface and could be useful across the field of orthopaedic research.

Background

Perceived instability is a primary symptom among individuals with chronic ankle instability. However, the relationship between joint kinematics during landing remains unclear. Therefore, we investigated the relationships between landing kinematics and perceived instability in individuals with chronic ankle instability.

Methods

In 32 individuals with chronic ankle instability, we recorded ankle, knee, and hip joint angles during a single-leg drop landing. Joint angle waveforms during 200 ms before and after initial contact were summarized into single values using two methods: peak joint angles and principal component scores via principal component analysis. Using Spearman's rank correlation coefficient (ρ), we examined the relationships of peak joint angles and principal component scores with the Cumberland Ankle Instability Tool score, with a lower score indicating a greater perceived instability (α = 0.05).

Findings

The second principal component scores of ankle angle in the horizontal and sagittal planes significantly correlated with the Cumberland Ankle Instability Tool score (Horizontal: ρ = 0.507, P = 0.003; Sagittal: ρ = −0.359, P = 0.044). These scores indicated the differences in the magnitude of angles before and after landing. Significant correlations indicated a greater perceived instability correlated with smaller internal rotation and plantarflexion before landing and smaller external rotation and dorsiflexion after landing. In contrast, no peak joint angles correlated with the Cumberland Ankle Instability Tool score (P > 0.05).

Interpretation

In individuals with chronic ankle instability, ankle movements during landing associated with perceived instability may be a protective strategy before landing and potentially cause ankle instability after landing.

Background

Individuals with Parkinson's disease are challenged in making turns while walking, evidenced by reduced intersegmental coordination and reduced dynamic postural stability. Although overground locomotor training previously improved ambulation among people with Parkinson's disease, its effect on walking turns remained unknown. We sought to understand the effects of overground locomotor training on walking turns among individuals with mild-Parkinson's disease.

Methods

Twelve participants with Parkinson's (7 Males/5 Females; Age: 68.5 ± 6.4 years) completed twenty-four sessions lasting approximately 60 min and over 12–15 weeks. Baseline and follow-up assessments included the ten-minute walk test using wearable sensors. Primary outcomes included changes to intersegmental coordination, measured by peak rotation and normalized peak rotation, and dynamic postural stability, measured by peak turn velocities in the frontal and transverse planes. Statistical analysis included one-tailed paired t-tests and Cohen's d effect sizes with α = 0.05.

Findings

No effects of overground locomotor training on mean peak thoracic rotation (+0.23 ± 4.24°; Cohen's d = 0.05; P = 0.45) or mean normalized peak thoracic rotation (−0.59 ± 5.52 (unitless); Cohen's d = 0.10; P = 0.45) were observed. Moderate and small effects of overground locomotor training were observed on mean peak turn velocities in the frontal (+1.59 ± 2.18°/s; Cohen's d = 0.43; P = 0.01) and transverse planes (+0.88 ± 3.18°/s; Cohen's d = 0.25; P = 0.18).

Interpretation

This pilot study provides preliminary evidence suggesting that individuals with mild-Parkinson's moderately improved frontal plane dynamic postural stability after overground locomotor training, likely attenuating the perturbations experienced while turning.

Clinical Trial Registration: NCT03864393