Renan A. Resende

Aplicação da análise de componentes principais na cinemática da marcha de idosas com osteoartrite de joelho

BACKGROUND: The applicability of gait analysis has been implemented with the introduction of the principal component analysis (PCA), a statistical data reduction technique that allows the comparison of the whole cycle between groups of individuals. OBJECTIVES: Applying PCA, to compare the kinematics of the knee joint during gait, in the frontal and sagittal planes, between a group of elderly women with and without diagnosis in the initial and moderate stages of Osteoarthritis (OA). METHODS: A total of 38 elderly women (69.6±8.1 years) with knee OA and 40 asymptomatic (70.3±7.7 years) participated on this study. The kinematics was obtained using the Qualisys Pro-reflex system. RESULTS: The OA group showed decreased gait velocity and stride length (p<0.05) and was characterized with higher WOMAC pain score. In the frontal plane, the between-group differences of the components were not significant. In the sagittal plane, three principal components explained 99.7% of the data variance. Discriminant analysis indicated that component 2 and 3 could classify correctly 71.8% of the individuals. However, CP3, which captures the difference in the flexion knee angle magnitude during gait, was the variable with higher discrimination power between groups. CONCLUSIONS: PCA is an effective multivariate statistical technique to analyse the kinematic gait waveform during the gait cycle. The smaller knee flexion angle in the OA group was appointed as a discriminatory factor between groups, therefore, it should be considered in the physical therapy evaluation and treatment of elderly women with knee OA.

Increased unilateral foot pronation affects lower limbs and pelvic biomechanics during walking

BACKGROUND Increased unilateral foot pronation may cause biomechanical changes on the lower limbs during gait. We investigated the effects of increased unilateral foot pronation on the biomechanics of lower limbs and pelvis during gait. METHODS Kinematic and kinetic data of 22 participants were collected while they walked wearing flat and laterally wedged sandals. Principal omponent analysis was used to compare differences between conditions. FINDINGS Wearing the wedged sandal on the ipsilateral side increased ankle eversion moment (p<0.001; effect size=0.97); rearfoot eversion angle (p<0.001; effect size=0.76); shank internal rotation (p=0.009; effect size=0.53); increased and reduced knee internal rotation angle during early and late stance, respectively (p<0.001; effect size=0.89); increased femur internal rotation (p=0.005; effect size=0.90); reduced hip internal rotation moment during late stance (p=0.001; effect size=0.68); and increased pelvic ipsilateral drop (p=0.02; effect size=0.48) of the ipsilateral side. Wearing the wedged sandal on the contralateral side increased pelvic contralateral drop (p=0.001; effect size=0.63); hip adduction moment throughout stance (p=0.027; effect size=0.46); and increased and reduced the knee adduction moment in early and late stance, respectively (p<0.001; effect size=0.79). INTERPRETATION The increased lower limb internal rotation caused by the wedged sandal reinforces the assumption that rearfoot eversion is coupled with shank internal rotation. The increased pelvic contralateral drop caused by the wedged sandal on the contralateral side may explain the increased hip and knee adduction moments on the ipsilateral side. Increased unilateral foot pronation causes biomechanical changes on both lower limbs that are associated with the occurrence of injuries.

Biomechanical strategies implemented to compensate for mild leg length discrepancy during gait

Although mild leg length discrepancy is related to lower limb injuries, there is no consensus regarding its effects on the biomechanics of the lower limbs during gait. Biomechanical data of 19 healthy participants were collected while they walked under different conditions as described: (1) control condition-wearing flat thick sandals; (2) short limb condition-wearing a flat thick sandal on the left and a flat thin sandal on the right foot; (3) long limb condition: wearing flat thin sandal on the left and flat thick sandal on the right foot. The thick and thin sandals had 1.45cm of mean thickness difference. The right lower limb data were analyzed for all conditions. Ankle, knee, hip and pelvis kinematics and internal moments were measured with a motion capture system and six force platforms. Principal component analysis was used to compare differences between conditions. The scores of the principal components were compared between conditions using one-way repeated measures ANOVA. Twelve gait variables were different between conditions: rearfoot dorsiflexion and inversion (p<0.001); ankle dorsiflexion and inversion moments (p<0.001); knee flexion angle and moment (p<0.001); knee adduction moment (p<0.001); hip flexion angle and moment (p<0.001); hip adduction angle (p=0.001) and moment (p=0.022); and pelvic ipsilateral drop (p<0.001). Mild leg length discrepancy caused compensatory changes during gait, apparently to equalize the functional length of the lower limbs. However, these strategies did not fully succeed, since both short and long limb conditions affected pelvic motion in the frontal plane. These results suggest that mild leg length discrepancy should not be overlooked in clinical settings.

Increased hip internal abduction moment and reduced speed are the gait strategies used by women with knee osteoarthritis

The purpose of this study was to identify the gait strategies in women with mild and moderate knee osteoarthritis (OA). Forty women diagnosed with OA of the knee and 40 healthy women participated in the study. Toe-out progression angle, trunk lateral lean, hip internal abduction moment and gait speed were measured using Qualisys ProReflex System and two force plates. Principal component analysis was applied to extract features from the gait waveforms data that characterized the waveforms main modes of temporal variation. Discriminant analysis with a stepwise model was conducted to determine which strategies could best discriminate groups. According to the discriminant model, the PC2 of the internal abduction moment of the hip and the gait speed were the most discriminatory variables between the groups. The OA group showed decreased gait speed, decreased hip internal abduction moment during the loading response phase, and increased hip internal abduction moment during the mid and terminal stance phases. Interventions that may increase hip internal abduction moment, such as the strengthening of the hip abductors muscles, may benefit women with knee OA. Training slower than normal gait speeds must be considered in light of potential adverse implications on overall physical function, daily tasks, and safety.

Ipsilateral and contralateral foot pronation affect lower limb and trunk biomechanics of individuals with knee osteoarthritis during gait

BACKGROUND Lateral wedges have been suggested for the treatment of individuals with knee osteoarthritis, but it may have undesirable effects on the biomechanics of gait through increased foot pronation. This study investigated the effects of increased unilateral foot pronation on the biomechanics of individuals with knee osteoarthritis during gait. METHODS Biomechanical data of twenty individuals with knee osteoarthritis were collected while they walked in three conditions: i) flat sandals; ii) wedged sandal on the knee osteoarthritis limb and flat sandal on the healthy limb; and iii) flat sandal on the osteoarthritis and wedged sandal on the healthy limb. Knee pain and comfort were evaluated. Principal Component Analysis followed by ANOVA was implemented to identify differences between conditions. FINDINGS The wedged sandal on the osteoarthritis limb increased rearfoot eversion (P<0.001; ES=0.79); increased shank rotation range of motion (P<0.001; ES=0.70); reduced knee internal rotation moment (P<0.001; ES=0.83); reduced hip internal rotation moment (P=0.001; ES=0.66); increased ipsilateral trunk lean (P=0.031; ES=0.47); and increased trunk rotation range of motion (P=0.001; ES=0.69). Walking with the wedged sandal on the healthy limb increased hip (P=0.003; ES=0.61) and knee (P=0.002; ES=0.63) adduction moments. Individuals reported greater comfort walking with the flat sandals (P=0.004; ES=0.55). INTERPRETATION Increased unilateral foot pronation of the knee osteoarthritis and healthy limbs causes lower limb and trunk mechanical changes that may overload the knee and the lower back, such as increased knee adduction moment, shank rotation and trunk lateral lean. Foot motion of both lower limbs should be evaluated and care must be taken when suggesting lateral wedges for individuals with knee osteoarthritis.

Power at hip, knee and ankle joints are compromised in women with mild and moderate knee osteoarthritis.

BACKGROUND Analyses of the biomechanical characteristics of gait of women with mild and moderate knee osteoarthritis may identify parameters that could be targeted by physical therapy interventions. Therefore, the purpose of the present study was to compare the joint power profiles during gait between a group of elderly women with mild and moderate levels of knee osteoarthritis and a group of age-matched asymptomatic women. METHODS Thirty-nine women diagnosed with osteoarthritis at the medial compartment of the knee and 39 healthy women with no diagnosis of knee osteoarthritis participated in the study. Joint power profiles of the hip, knee and ankle joints in the sagittal plane during gait were performed using video and force data obtained using Qualisys ProReflex System synchronized with two force plates. Principal component analysis was applied to extract features from the joint power waveforms characterizing their main modes of temporal variation. The extracted features were compared between groups. FINDINGS Women with knee osteoarthritis absorbed and generated less energy at the hip and ankle joints, and absorbed less energy at the knee when compared to the asymptomatic group. INTERPRETATION The observed power pattern in women with knee osteoarthritis may be related to their reduced gait speed, a suboptimal strategy possibly used to reduce reaction forces at the knee. Clinical studies should investigate whether interventions designed to improve muscular resources, as a means to control the flow of forces at the knee, would optimize power patterns and gait performance in women with knee osteoarthritis.

Sistema GaitGrabber na captação de dados cinemáticos durante a marcha

The purpose of this study was to develop and test the validity and reliability of the GaitGrabber System in measuring kinematic variables in the sagittal plane during gait. Eighteen individuals participated in the reliability study and 28 in the concurrent validity study. The Qualisys Pro-Reflex System used as a gold standard reference system. The GaitGrabber calculates the relative angles at the hip, knee and ankle in the sagittal plane. The Intraclass Correlation Coefficient (ICC) was used to compare the average of the angular peaks between visits. The principal component analysis was used to test the validity of the system. The ICC ranged from moderate to excellent and the validity of the system was proved for the ankle. There were significant differences in the range of motion for the hip and knee joints which were attributed to different instrumental characteristics. The GaitGrabber system is valid and reliable and can be clinically used to analyze kinematics during gait in the sagittal plane.

Hip and Knee Strengthening Is More Effective Than Knee Strengthening Alone for Reducing Pain and Improving Activity in Individuals With Patellofemoral Pain: A Systematic Review With Meta-analysis

• STUDY DESIGN: Systematic review with meta‐analysis. • BACKGROUND: The addition of hip strengthening to knee strengthening for persons with patellofemoral pain has the potential to optimize treatment effects. There is a need to systematically review and pool the current evidence in this area. • OBJECTIVE: To examine the efficacy of hip strengthening, associated or not with knee strengthening, to increase strength, reduce pain, and improve activity in individuals with patellofemoral pain. • METHODS: A systematic review of randomized and/or controlled trials was performed. Participants in the reviewed studies were individuals with patellofemoral pain, and the experimental intervention was hip and knee strengthening. Outcome data related to muscle strength, pain, and activity were extracted from the eligible trials and combined in a meta‐analysis. • RESULTS: The review included 14 trials involving 673 participants. Random‐effects meta‐analyses revealed that hip and knee strengthening decreased pain (mean difference, ‐3.3; 95% confidence interval [CI]: ‐5.6, ‐1.1) and improved activity (standardized mean difference, 1.4; 95% CI: 0.03, 2.8) compared to no training/placebo. In addition, hip and knee strengthening was superior to knee strengthening alone for decreasing pain (mean difference, ‐1.5; 95% CI: ‐2.3, ‐0.8) and improving activity (standardized mean difference, 0.7; 95% CI: 0.2, 1.3). Results were maintained beyond the intervention period. Meta‐analyses showed no significant changes in strength for any of the interventions. • CONCLUSION: Hip and knee strengthening is effective and superior to knee strengthening alone for decreasing pain and improving activity in persons with patellofemoral pain; however, these outcomes were achieved without a concurrent change in strength. • LEVEL OF EVIDENCE: Therapy, level 1a‐.

External rotation elastic bands at the lower limb decrease rearfoot eversion during walking: a preliminary proof of concept

ABSTRACT Background Reducing rearfoot eversion is a commonly desired effect in clinical practice to prevent or treat musculoskeletal dysfunction. Interventions that pull the lower limb into external rotation may reduce rearfoot eversion. Objective This study investigated whether the use of external rotation elastic bands, of different levels of stiffness, will decrease rearfoot eversion during walking. We hypothesized that the use of elastic bands would decrease rearfoot eversion and that the greater the band stiffness, the greater the eversion reduction. Method Seventeen healthy participants underwent three-dimensional kinematic analysis of the rearfoot and shank. The participants walked on a treadmill with and without high- and low-stiffness bands. Frontal-plane kinematics of the rearfoot-shank joint complex was obtained during the stance phase of walking. Repeated-measures ANOVAs were used to compare discrete variables that described rearfoot eversion-inversion: mean eversion-inversion; eversion peak; and eversion-inversion range of motion. Results The low-stiffness and high-stiffness bands significantly decreased eversion and increased mean eversion-inversion (p≤0.037) and eversion peak (p≤0.006) compared with the control condition. Both bands also decreased eversion-inversion range of motion (p≤0.047) compared with control by reducing eversion. The high-stiffness band condition was not significantly different from the low-stiffness band condition for any variables (p≥0.479). Conclusion The results indicated that the external rotation bands decreased rearfoot eversion during walking. This constitutes preliminary experimental evidence suggesting that increasing external rotation moments at the lower limb may reduce rearfoot eversion, which needs further testing.

Women With Early Stages of Knee Osteoarthritis Demonstrate Lower Mechanical Work Efficiency at the Knee

The purpose of this study was to investigate the mechanical work of the hip, knee, and ankle in females with mild and moderate levels of knee osteoarthritis (OA). Thirty-nine women with knee OA and 39 healthy women participated in the study. Mechanical work expenditures at the hip, knee, and ankle were computed using data obtained during gait. Knee total and absorptive mechanical work was lower for the OA group. Muscle weakness and pain may have contributed to the lower mechanical efficiency of the knee, which may help explain the lower level of physical function demonstrated by women with knee OA.