The effect of kinetic factors of dynamic knee valgus on patellofemoral pain: A systematic review and meta-analysis.

The speculation of dynamic knee valgus (DKV) correlates with kinetic changes in the frontal plane that increased loading patellofemoral joint (PFJ). Therefore, it is the purpose of this systematic review and meta-analysis study is the effect of kinetic factors DKV on patellofemoral pain (PFP). The search strategy was carried out in the electronic databases of Cochrane Library, PubMed, Springer Link, Science Direct, Scopus. Studies limited to the period 2000 to 2020 were extracted. The quality of study was assessment by modified Downs and Black checklist. Mean and standard deviation were also used to calculate the effect size. There were selected 8 articles for the systematic review and Meta-analysis. The results showed that in PFP patients compared to healthy individuals have increase knee abduction moment (SMD = 0.75; 95% CI = [0.47 to 1.02]) and impulse (SMD = 0.79; 95% CI = [0.50 to 1.07]). Furthermore, PFP patients compared to healthy individuals have decrease onset (SMD = -0.60; 95% CI = [-1.03 to -0.17]) and during (SMD = -0.93; 95% CI = [-1.57 to -0.29]) gluteus medius (GMED); vis-à-vis, PFP patients compared to healthy individuals have increase onset (SMD = 0.10; 95% CI = [-0.34 to 0.54]) and during (SMD = 0.29; 95% CI = [-0.15 to 0.73]) adductors longus (AL). As a result; PFP patients compared to healthy individuals show decrease co-contraction GMED/AL (SMD = -1.03; 95% CI = [-1.83 to -0.24]). The kinetic factors of DKV of leading to PFJ contact area decreases and the loading in a smaller contact area on PFJ in the outer part of the patella. Eventually, this abnormal distribution of contact pressure leads to etiology and osteoarthritis of the PFP.

Relationship between exacerbating patellofemoral pain and dynamic knee valgus in females with patellofemoral pain after a patellofemoral joint loading protocol: A cross-sectional.

OBJECTIVE: The aim of the present study is to 1) the effect of exacerbating patellofemoral pain (PFP) on dynamic knee valgus (DKV) 2) the relationship between exacerbating PFP and DKV in females with patellofemoral pain. DESIGN: Cross-sectional study. METHODS: Sixty women with PFP were recruited from the orthopedic clinics. We evaluated pain intensity and DKV in two conditions without (condition 1) and with (condition 2) PFJ loading during the single-leg squat (SLS) task. The MANOVA test was used to compare pain intensity and DKV angle between the two conditions. Furthermore, the Pearson correlation was used to examine the correlation between pain intensity with DKV angle. RESULTS: The MANOVA analysis showed that pain intensity (P < 0.000, η2 = 0.623) and DKV angle (P < 0.000, η2 = 0.544) with a medium effect size significantly increased after PFJ loading. Furthermore, an excellent positive correlation was observed between an increase in pain intensity and DKV angle (P < 0.000, r = 0.840). CONCLUSION: It seems that after the PFJ loading protocol and the subsequent pain exacerbation, the neuromuscular biomechanics of the lower limb are deficits. As a result, the stabilizing muscles activation decreases and increases the lower limb movement in the frontal plane.

Effect of foot orthoses on dynamic balance in taekwondo athletes with flexible flatfoot: A randomized controlled trial.

BACKGROUND: Flexible flatfoot (FFF) cause biomechanical and sensorimotor disorders of the foot and ankle complex and reduce of postural stability. Postural stability is an important movement skill that affects the performance of taekwondo (TKD) athletes and can lead to fall injuries. The purpose of this study is the effect 12-week application of foot orthosis (FOs) on dynamic balance in TKD athletes with FFF. METHOD: In this trial, 30 girls of the TKD athletes with FFF were recruited. They were randomly assigned to experimental and control groups (15 subjects in each group). The experimental group used FOs with medial longitudinal arch support for 12 weeks, and the control group did not have any intervention. The outcome measures include navicular drop and balance in three directions: anterior-posterior, medial-lateral and overall stability. Covariance analysis was used to compare the results between two groups. RESULTS: The covariance results showed that the experimental group compared to the control group with a high effect size had a significant difference in reducing of navicular drop (P = 0.000, ηp2 =0.512), anterior-posterior sway (P = 0.000, (ηp2 =0.397) medial-lateral sway (P = 0.019, ηp2 = 0.186) and overall stability sway (P = 0.008, ηp2 = 0.232). CONCLUSIONS: The FOs with medial longitudinal arch support leads to FFF correction and provides mechanical stability of the foot and ankle complex. Also, the impulses sent from plantar receptors are increased and a better understanding of postural sway is transmitted to the central nervous system and balance strategies are improved.

Patients with Patellofemoral Pain Exhibiting Decrease Vertical Ground Reaction Force Compared to Healthy Individuals during Weight Bearing Tasks: A Systematic Reviews and Meta-Analysis.

Background: Vertical ground reaction force (VGRF) can lead to the development knee osteoarthritis. This review systematic and meta-analysis aimed to investigate the VGRF in patellofemoral pain patients (PFP) during weight bearing tasks. Methods: Search strategy was conducted in databases: Science Direct, Scopus, PubMed and Google Scholar from Sep 2020 to Jun 2021. The VGRF components we measured were passive impact (Fz1)/peak and propulsion/active peak (Fz2). The quality of the studies was evaluated with Down and Black index and it was divided into three groups: low quality (LQ), medium quality (MQ) and high quality (HQ). The standardized mean difference between PFP and healthy individuals was used to calculate the effect size. Results: Nine articles were selected for systematic review and meta-analysis of which 5 studies was HQ, 3 studies were MQ and 1 study was LQ were classified. PFP compared to healthy individuals with moderate and small effect size have reduced impact and propulsion respectively. Conclusion: The in PFP, VGRF is influenced psychological, behavioral and biomechanical factors. Therefore, psychosomatic therapeutic approaches may have a long time effectiveness on the rehabilitation of PFP.

Robust H∞ control of uncertain switched systems defined on polyhedral sets with Filippov solutions.

This paper considers the control problem of a class of uncertain switched systems defined on polyhedral sets known as piecewise linear systems where, instead of the conventional Carathéodory solutions, Filippov solutions are studied. In other words, in contrast to the previous studies, solutions with infinite switching in finite time along the facets and on faces of arbitrary dimensions are also taken into account. Firstly, established upon previous studies, a set of linear matrix inequalities are brought forward which determines the asymptotic stability of piecewise linear systems with Filippov solutions. Subsequently, bilinear matrix inequality conditions for synthesizing a robust controller with a guaranteed H(∞) performance are presented. Furthermore, these results has been generalized to the case of piecewise affine systems. Finally, a V-K iteration algorithm is proposed to deal with the aforementioned bilinear matrix inequalities. The validity of the proposed method is verified through the analysis of two simulation examples.