Variable Stiffness Shoes Research Articles

Variable Stiffness Shoes for Knee Osteoarthritis: An Evaluation of 3-Dimensional Gait Mechanics and Medial Joint Contact Forces.

The study aim was to quantify the impact of a commercially available variable stiffness shoe (VSS) on 3-dimensional ankle, knee, and hip mechanics and estimated knee contact forces compared with a control shoe. Fourteen participants (10females) with knee osteoarthritis completed gait analysis after providing informed consent. Shoe conditions tested were control shoe (New Balance MW411v2) and VSS (Abeo SMART3400). An OpenSim musculoskeletal model with static optimization was used to estimate knee contact forces. There were no differences in joint kinematics or in the knee adduction or flexion moments (P = .06; P = .2). There were increases in the knee internal and external rotation (P = .02; P = .03) and hip adduction and internal rotation moments for VSS versus control (P = .03; P = .02). The estimated contact forces were not different between shoes (total P = .3, medial P = .1, and lateral P = .8), but contact force changes were correlated with changes in the knee adduction moment (medial r2 = .61; P < .007). High variability in knee flexion moment changes and increases in the internal rotation moment combined with small decreases in the knee adduction moment did not lead to decreases in estimated contact forces. These results suggest that evaluation of VSS using only the knee adduction moment may not adequately capture its impact on osteoarthritis.

Layer Jamming for Variable Stiffness Shoes

In this work we presented the application of the layer jamming technology as variable stiffness mechanism for tech approach shoes. This scenario leads to the development of a novel kind of layer jamming system, with significant stiffness variation, yet minimized shape-locking effect. The system performances have been evaluated through subsequent experimental tests. This also allowed to better understand the behavior of shoes with different features. The results led to the identification of solutions with satisfactory performances with respect to target values and with the potential to be extended also to shoes with different requirements. The generality of the final considerations drawn for the examined application could lead to a novel way to exploit the layer jamming technology in different scenarios.

Physical therapy and orthopaedic equipment-induced reduction in the biomechanical risk factors related to knee osteoarthritis: a systematic review and Bayesian network meta-analysis of randomised controlled trials

ObjectiveAre physical therapy or orthopaedic equipment efficacious in reducing the biomechanical risk factors in people with tibiofemoral osteoarthritis (OA)? Is there a better therapeutic intervention than others to improve these...

Changes in knee adduction moment wearing a variable-stiffness shoe correlate with changes in pain and mechanically stimulated cartilage oligomeric matrix levels.

This study aimed to determine if changes in knee adduction moment (KAM) after 6 months of variable-stiffness shoe wear are associated with changes in symptoms or serum levels of cartilage oligomeric matrix protein (COMP) following a mechanical stimulus in subjects with medial knee osteoarthritis (OA). Twenty-five subjects were enrolled in the study and assigned a variable-stiffness shoe, and 19 subjects completed the 6-month follow-up. At baseline and follow-up subjects underwent gait analysis in control and variable-stiffness shoes, completed Western Ontario and McMaster Universities (WOMAC) questionnaires, and serum COMP concentrations were measured immediately before, 3.5 and 5.5 hours after a 30-minute walking activity. Relationships between changes in KAM (first peak and impulse) and changes in (a) COMP levels in response to the 30-minute walking activity and (b) WOMAC scores from baseline to 6-month follow-up were assessed by Pearson correlation coefficients. Changes in first peak KAM were associated with changes in COMP levels 5.5 hours postactivity from baseline to follow-up (R = .564, P = .045). Subjects with greater reductions in KAM had larger decreases in COMP (expressed as a percent of preactivity levels) at follow-up. Subjects with greater reductions in KAM impulse had significantly greater improvements in WOMAC Pain (R = -.56, P = .015) and Function (R = -.52, P = .028) scores at follow-up. The study results demonstrated the magnitude of reduction in the KAM wearing a variable-stiffness shoe is associated with decreases in mechanically stimulated COMP levels and pain/function. This work suggests that interactions between COMP and joint loading during walking should be further investigated in future studies of treatment outcomes in OA.

Relationship between changes in the knee adduction moment and medial compartment contact force with variable stiffness shoes

Purpose: Despite early promising results of Variable Stiffness Shoes (VSS) on pain and function in medial compartment knee osteoarthritis (OA) patients, randomized controlled trials have not found a significant effect on structural disease progression. Significant biomechanical effects of VSS have been found with several studies showing reductions in the external knee adduction moment (KAM) for healthy, mild, moderate and severe medial compartment knee OA participants as compared to shoes with homogenous midsole stiffness.

Biomechanical Effects of Variable Stiffness Shoes in Normal Walking After 60-minute Adaptation

The use of variable stiffness shoes (VSS) has been found to be conducive to reducing external knee adduction moment (EKAM). However, it is still unknown whether the claimed biomechanical effects of VSS remain after the subjects have adapted to the footwear. The objective of the study is to examine the effects of VSS immediately upon usage, as well as its effects after 60 min of adaptation. It is hypothesized that the lowering of EKAM is not just the short term biomechanical response due to the immediate use of VSS. Twenty subjects were instructed to walk in three shod conditions which are walking in control shoes, walking in VSS, and walking in VSS after 60-min of adaptation. All of the dynamic exercises were recorded simultaneously by VICON Motion Systems (Oxford Metric, UK). The results showed that EKAM was significantly reduced with the immediate use of VSS (8.43%, p < 0.05), as compared to the control shoes. The reduction remained significant, even after the given 60-min adaptation time. The effect of VSS on the reduction of EKAM is found to be consistent, even after familiarization. The use of VSS is postulated to be helpful in alleviating the loading across the medial compartment of the knee joint.

Impact of variable stiffness shoes on medial knee contact forces

Impact of variable stiffness shoes on medial knee contact forces

Changes in knee adduction moment with a variable-stiffness shoe are related to changes in pain and function

Changes in knee adduction moment with a variable-stiffness shoe are related to changes in pain and function

Biomechanical effects of variable stiffness shoes in normal walking after 60-minute adaptation

"Biomechanical effects of variable stiffness shoes in normal walking after 60-minute adaptation." Footwear Science, 9(sup1), pp. S146–S147

The effects of shoes on knee pain and medial joint loading in persons with knee osteoarthritis: A systematic review with meta-analysis

The effects of shoes on knee pain and medial joint loading in persons with knee osteoarthritis: A systematic review with meta-analysis

Osgood Schlatter Disease—An ultrasound grading system with practical application

Athletes who sustain a knee joint injury, namely to the anterior cruciate ligament and/or meniscus, are at an increased risk of subsequent osteoarthritis (OA) – the so-called ‘young people with old knees’. Surgical intervention does not appear to reduce this increased risk. There is no good evidence that moderate sporting activity in thepresenceofnormal jointspredisposes toOA.Whether high-level participation in sport, particularly impact type sports, is associatedwithOA is unclear as it is difficult to disentangle the confounding effect of joint injury. Attention to strategies that prevent joint injury in athletes, such as neuromuscular exercise, is therefore paramount to reduce the burden of OA. Optimal management is needed to minimize the onset and extent of joint symptoms in athletes following joint injury. Clinicians should counsel the athlete about their increased likelihood of future OA as this allows athletes to make informed decisions about return to sport as well as plan future management. Prevention and management of OA in athletes includes use of load-reducing strategies such as variable stiffness shoes, bracing, activity modification, muscle strengthening and weight control although these have not been tested in clinical trials in athletes. There are currently no pharmacologic agents with convincing structural disease-modifying efficacy for people with existing joint damage and most have been tested in midto late-term OA rather than early OA. There are no high quality clinical trials investigating the effects of platelet-rich plasma therapy in treatment of knee OA. Evidence for a possible structuremodifying effect of glucosamine, the most commonly used dietary supplement for OA, is still controversial.

Maximising joint health: Preventing and managing knee osteoarthritis in the athlete

Athletes who sustain a knee joint injury, namely to the anterior cruciate ligament and/or meniscus, are at an increased risk of subsequent osteoarthritis (OA) – the so-called ‘young people with old knees’. Surgical intervention does not appear to reduce this increased risk. There is no good evidence that moderate sporting activity in thepresenceofnormal jointspredisposes toOA.Whether high-level participation in sport, particularly impact type sports, is associatedwithOA is unclear as it is difficult to disentangle the confounding effect of joint injury. Attention to strategies that prevent joint injury in athletes, such as neuromuscular exercise, is therefore paramount to reduce the burden of OA. Optimal management is needed to minimize the onset and extent of joint symptoms in athletes following joint injury. Clinicians should counsel the athlete about their increased likelihood of future OA as this allows athletes to make informed decisions about return to sport as well as plan future management. Prevention and management of OA in athletes includes use of load-reducing strategies such as variable stiffness shoes, bracing, activity modification, muscle strengthening and weight control although these have not been tested in clinical trials in athletes. There are currently no pharmacologic agents with convincing structural disease-modifying efficacy for people with existing joint damage and most have been tested in midto late-term OA rather than early OA. There are no high quality clinical trials investigating the effects of platelet-rich plasma therapy in treatment of knee OA. Evidence for a possible structuremodifying effect of glucosamine, the most commonly used dietary supplement for OA, is still controversial.

A Biomechanical Perspective on Physical Therapy Management of Knee Osteoarthritis

Altered knee joint biomechanics and excessive joint loading have long been considered as important contributors to the development and progression of knee osteoarthritis. Therefore, a better understanding of how various treatment options influence the loading environment of the knee joint could have practical implications for devising more effective physical therapy management strategies. The aim of this clinical commentary was to review the pertinent biomechanical evidence supporting the use of treatment options intended to provide protection against excessive joint loading while offering symptomatic relief and functional improvements for better long-term management of patients with knee osteoarthritis. The biomechanical and clinical evidence regarding the effectiveness of knee joint offloading strategies, including contralateral cane use, laterally wedged shoe insoles, variable-stiffness shoes, valgus knee bracing, and gait-modification strategies, within the context of effective disease management is discussed. In addition, the potential role of therapeutic exercise and neuromuscular training to improve the mechanical environment of the knee joint is considered. Management strategies for treatment of joint instability and patellofemoral compartment disease are also mentioned. Based on the evidence presented as part of this clinical commentary, it is argued that special considerations for the role of knee joint biomechanics and excessive joint loading are necessary in designing effective short- and long-term management strategies for treatment of patients with knee osteoarthritis. Therapy, level 5.

Kinetics and kinematics effects of variable stiffness shoe on lower extremity

Many surgical and mechanical interventions such as high tibial osteotomy and lateral wedged insole are designed to tackle this problem. Surgery slows the rate of cartilage breakdown by changing the...

Investigation of the biomechanical effect of variable stiffness shoe on external knee adduction moment in various dynamic exercises

BackgroundThe growing ageing population and high prevalence of knee osteoarthritis (OA) in athletes across nations have created a strong demand for improved non-invasive therapeutic alternatives for knee OA. The aim of this study is to investigate the effect of the variable stiffness shoe (VSS), a new non-invasive therapeutic approach, on external knee adduction moment (EKAM) in various dynamic exercises. EKAM is believed to have positive correlation with the progression and development of knee OA.MethodsThirty young participants (16 male and 14 female; age 22.6 ± 1.9 years) from National University of Singapore were enrolled in this study. The tested activities were walking, running, drop-landing, and lateral hopping. All the dynamic exercises were recorded simultaneously by the 8-camera VICON Motion Systems (Oxford Metric, UK) with a sampling rate of 100 Hz.ResultsThe results showed that the EKAM was reduced in all the dynamic exercises with the use of VSS. The VSS produced significant reductions in the peak EKAM during walking (4.97%, p = 0.039), running (11.15%, p = 0.011), drop-landing (11.18%, p = 0.038) and lateral hopping (17.34%, p = 0.023) as compared to the control shoe.ConclusionsThe reduction of EKAM with the use of VSS in various dynamic exercises demonstrates its potential in delaying the onset and the progression of knee OA in early stage of knee OA patients.

Kinematic adaptations to a variable stiffness shoe: Mechanisms for reducing joint loading

A recently described variable-stiffness shoe has been shown to reduce the adduction moment and pain in patients with medial-compartment knee osteoarthritis. The mechanism associated with how this device modifies overall gait patterns to reduce the adduction moment is not well understood. Yet this information is important for applying load modifying intervention for the treatment of knee osteoarthritis.A principal component analysis (PCA) was used to test the hypothesis that there are differences in the frontal plane kinematics that are correlated with differences in the ground reaction forces (GRFs) and center of pressure (COP) for a variable-stiffness compared to a constant-stiffness control shoe. Eleven healthy adults were tested in a constant-stiffness control shoe and a variable-stiffness shoe while walking at self-selected speeds. The PCA was performed on trial vectors consisting of all kinematic, GRF and COP data.The projection of trial vectors onto the linear combination of four PCs showed there were significant differences between shoes. The interpretation of the PCs indicated an increase in the ankle eversion, knee abduction and adduction, decreases in the hip adduction and pelvic obliquity angles and reduced excursion of both the COP and peak medial–lateral GRFs for the variable-stiffness compared to the control shoe.The variable-stiffness shoe produced a unique dynamic change in the frontal plane motion of the ankle, hip and pelvis that contributed to changes in the GRF and COP and thus reduced the adduction moment at a critical instant during gait suggesting a different mechanism that was seen with fixed interventions (e.g. wedges).

Influence of variable stiffness shoes in sports performance and protection of lower extremity injury

Influence of variable stiffness shoes in sports performance and protection of lower extremity injury

Gait Modification to Treat Knee Osteoarthritis

By changing pathological joint mechanics, gait modification may have disease modifying potential for medial compartment knee OA. The most effective gait modification methods may well be a combination of an assisted modification and a learned modification taught via a real-time feedback system—for example, variable stiffness shoes with medial thrust gait. Addition of other holistic elements such as strength or flexibility training may be valuable as well. Determination of the best target quantity will be critical for gait modification to make a positive clinical impact.

Effect of variable‐stiffness walking shoes on knee adduction moment, pain, and function in subjects with medial compartment knee osteoarthritis after 1 year

This study investigated the load-modifying and clinical efficacy of variable-stiffness shoes after 12 months in subjects with medial compartment knee osteoarthritis. Subjects who completed a prior 6-month study were asked to wear their assigned constant-stiffness control or variable-stiffness intervention shoes during the remainder of the study. Changes in peak knee adduction moment, total Western Ontario and McMaster Universities (WOMAC), and WOMAC pain scores were assessed. Seventy-nine subjects were enrolled, and 55 completed the trial. Using an intention-to-treat analysis, the variable-stiffness shoes reduced the within-day peak knee adduction moment (-5.5%, p < 0.001) in the intervention subjects, while the constant-stiffness shoes increased the peak knee adduction moment in the control subjects (+3.1%, p = 0.015) at the 12-month visit. WOMAC pain and total scores for the intervention group were significantly reduced from baseline to 12 months (-32%, p = 0.002 and -35%, p = 0.007, respectively). The control group had a reduction of 27% in WOMAC pain score (p = 0.04) and no significant reduction in total WOMAC score. Reductions in WOMAC pain and total scores were similar between groups (p = 0.8 and p = 0.47, respectively). In the intervention group, reductions in adduction moment were related to improvements in pain and function (R(2) = 0.11, p = 0.04). Analysis by disease severity revealed greater efficacy in adduction moment reduction in the less severe intervention group. While the long-term effects of the intervention shoes on pain and function did not differ from control, the data suggest wearing the intervention shoe reduces the within-day adduction moment after long-term wear, and thus should reduce loading on the affected medial compartment of the knee.

An analysis of the mechanisms for reducing the knee adduction moment during walking using a variable stiffness shoe in subjects with knee osteoarthritis

Variable stiffness shoes that have a stiffer lateral than medial sole may reduce the external knee adduction moment (EKAM) and pain during walking in patients with medial compartment knee osteoarthritis (OA). However, the mechanism by which EKAM may be reduced in the OA knee with this intervention remains unclear. Three hypotheses were tested in this study: (1) The reduction in EKAM during walking with the variable stiffness shoe is associated with a reduction in GRF magnitude and/or (2) frontal plane lever arm. (3) A reduction in frontal plane lever arm occurs either by moving the center of pressure laterally under the shoe and/or by dynamically reducing the medial component of GRF. Thirty-two subjects (20 male, 12 female; age: 58.7±9.3 years; height: 1.62±0.08 m; mass: 81.3±14.6 kg) with medial compartment knee osteoarthritis were studied walking in a gait laboratory. The frontal plane lever arm was significantly reduced (1.62%, 0.07%ht, p=0.02) on the affected side while the magnitude of the GRF was not significantly changed. The reduction in the lever arm was weakly correlated with a medial shift in the COP. However, the combined medial shift in the COP and reduction in the medial GRF explained 50% of the change of the frontal plane lever arm. These results suggest that the medial shift in the COP at the foot produced by the intervention shoe stimulates an adaptive dynamic response during gait that reduces the frontal plane lever arm.