Wedged Insoles and Gait in Patients with Knee Osteoarthritis: A Biomechanical Review

What improvements do general exercise training and traditional Chinese exercises have on knee osteoarthritis? A narrative review based on biological mechanisms and clinical efficacy

Background

Knee osteoarthritis (KOA) is a disease that significantly affects the quality of life of patients, with a complex pathophysiology that includes degeneration of cartilage and subchondral bone, synovitis, and associations with mechanical load, inflammation, metabolic factors, hormonal changes, and aging.

Objective

This article aims to comprehensively review the biological mechanisms and clinical effects of general exercise training and traditional Chinese exercises (such as Tai Chi and Qigong) on the treatment of KOA, providing references for the development of clinical exercise prescriptions.

Methods

A systematic search of databases including PubMed, Web of Science, Google Scholar, and China National Knowledge Infrastructure (CNKI) was conducted, reviewing studies including randomized controlled trials (RCTs), observational studies, systematic reviews, and meta-analyses. Keywords included "knee osteoarthritis," "exercise therapy," "physical activity," and "traditional Chinese exercise."

Results and conclusion

General exercise training positively affects KOA by mechanisms such as promoting blood circulation, improving the metabolism of inflammatory factors, enhancing the expression of anti-inflammatory cytokines, and reducing cartilage cell aging. Traditional Chinese exercises, like Tai Chi and Qigong, benefit the improvement of KOA symptoms and tissue repair by regulating immune function and alleviating joint inflammation. Clinical studies have shown that both types of exercise can improve physical function, quality of life, and pain relief in patients with KOA. Both general exercise training and traditional Chinese exercises are non-pharmacological treatment options for KOA that can effectively improve patients' physiological function and quality of life. Future research should further explore the long-term effects and biological mechanisms of these exercise interventions and develop personalized exercise programs based on the specific needs of patients.

Effect of short-term spinal orthosis and insoles application on cobb angle, plantar pressure and balance in individuals with adolescent idiopathic scoliosis

BACKGROUND

Spinal orthosis applications are preferred for conservative treatment of adolescent idiopathic scoliosis, and holistic biomechanical approaches are recommended.

METHODS

This was single-blind, prospective, randomized, controlled study. It included 42 patients (29 females/13 males) aged 10-18 years with adolescent idiopathic scoliosis, Cobb angle of 20°-45°, who were deemed suitable for spinal orthosis use. Patients were randomly divided into two groups: control, spinal orthosis group (n = 21), and insoles and spinal orthosis group (n = 21). All participants used spinal orthoses for 3 months. This study evaluated the functional capacities, quality of life, balance, and plantar pressures of the participants. The evaluations were repeated after 1 week, and 3 months following spinal orthosis application.

FINDINGS

Statistically significant difference and positive effect were observed in Cobb angle (p = 0.008; p = 0.878, respectively), right total (p = 0.037; p = 0.193, respectively), left total (p = 0.037; p = 0.193, respectively), left rearfoot (p = 0.002; p = 0.708, respectively), and right forefoot plantar pressure (p = 0.001; p = 0.739, respectively) in participants in insoles and spinal orthosis group compared with those in the control group. Statistically significant differences and positive effects were observed in swing length (p = 0.001; p = 0.053, respectively) and functional capacity (p = 0.005; p = 0.220, respectively), which are parameters related to postural balance. No change was found in quality of life of either group (p > 0.05).

INTERPRETATION

Insoles may have positive impact on functional capacity, balance, and plantar pressure during long-term follow-up in individuals with scoliosis. Therefore, the evaluation of foot plantar pressure in individuals with scoliosis is recommended, and personalized insoles may be a beneficial option.

Clinical value of ankle flexion and extension exercises combined with a psychological intervention in knee osteoarthritis

BACKGROUND

Considering the limited effectiveness of clinical interventions for knee osteoarthritis (KOA), it is necessary to continue to explore appropriate and effective treatment strategies to improve the condition of KOA patients.

AIM

To clarify the influence of ankle flexion and extension exercises combined with a psychological intervention on the psychological status and activities of daily living (ADLs) of patients with KOA.

METHODS

The research participants were 116 KOA patients admitted to The First Affiliated Hospital of Guizhou University of Traditional Chinese Medicine between May 2019 and May 2022, including 54 patients receiving routine treatment, care and psychological intervention (control group) and 62 patients additionally treated with ankle flexion and extension exercises (research group). The two groups were comparatively analyzed in terms of psychological status (Self-rating Anxiety/Depression Scale, SDS/SAS), ADLs, knee joint function (Lysholm Knee Scoring Scale), pain (Visual Analog Scale, VAS), fatigue (Multidimensional Fatigue Inventory, MFI), and quality of life (QoL; Short-Form 36 Item Health Survey, SF-36).

RESULTS

After evaluation, it was found that the postinterventional SDS, SAS, VAS, and MFI scores in the research group were significantly reduced compared with the baseline (before the intervention) values and those of the control group, while the postinterventional Lysholm, ADL and SF-36 scores were markedly elevated.

CONCLUSION

Therefore, ankle flexion and extension exercises are highly effective in easing negative psychological status, enhancing ADLs, daily living ability, knee joint function and QoL, and relieving pain and fatigue in KOA patients, thus warranting clinical promotion.

Impact of biomechanics on therapeutic interventions and rehabilitation for major chronic musculoskeletal conditions: A 50-year perspective

The pivotal role of biomechanics in the past 50 years in consolidating the basic knowledge that underpins prevention and rehabilitation measures has made this area a great spotlight for health practitioners. In clinical practice, biomechanics analysis of spatiotemporal, kinematic, kinetic, and electromyographic data in various chronic conditions serves to directly enhance deeper understanding of locomotion and the consequences of musculoskeletal dysfunctions in terms of motion and motor control. It also serves to propose straightforward and tailored interventions. The importance of this approach is supported by myriad biomechanical outcomes in clinical trials and by the development of new interventions clearly grounded on biomechanical principles. Over the past five decades, therapeutic interventions have been transformed from fundamentally passive in essence, such as orthoses and footwear, to emphasizing active prevention, including exercise approaches, such as bottom-up and top-down strengthening programs for runners and people with osteoarthritis. These approaches may be far more effective inreducing pain, dysfunction, and, ideally, incidence if they are based on the biomechanical status of the affected person. In this review, we demonstrate evidence of the impact of biomechanics and motion analysis as a foundation for physical therapy/rehabilitation and preventive strategies for three chronic conditions of high worldwide prevalence: diabetes and peripheral neuropathy, knee osteoarthritis, and running-related injuries. We conclude with a summary of recommendations for future studies needed to address current research gaps.

The efficacy of 3D personalized insoles in moderate adolescent idiopathic scoliosis: a randomized controlled trial

Background

Bracing and exercise methods were used in scoliosis rehabilitation and proven effective. There was little evidence about the efficacy of insoles on scoliosis.

Objective

This study aimed to investigate the effects of 3D personalized insoles on curve magnitude, postural stability, and quality of life (QOL) in moderate adolescent idiopathic scoliosis (AIS) patients.

Methods

Thirty-six volunteers with adolescent idiopathic scoliosis, who had moderate curves (20°-45°), were randomly divided into the experimental and control groups. The control group received traditional rehabilitation with bracing and exercises, and the experimental group received the insole interventions in addition to traditional rehabilitation. The outcome measures were Cobb angle, angle of trunk rotation (ATR), postural stability, and quality of life (Scoliosis Research Society-22 questionnaire). Measurements were conducted at baseline examination, two months and six months.

Results

After two and six months of treatment, the Cobb angle and ATR in both groups were significantly decreased as compared with the baseline (p < 0.05), but no significant group difference in Cobb angle and ATR was found in the study (p > 0.05). There was a significant difference in the sagittal balance index at six months compared to the control group (p < 0.05), and a significant difference in the coronal balance index was observed at six months compared to baseline in the experimental group (p < 0.05). Quality of life did not change in either group (p > 0.05).

Conclusion

Combining bracing with exercise in patients with moderate AIS is effective. 3D personalized insoles cannot reduce the Cobb angle and angle of trunk rotation of patients with moderate AIS but might have the potential to improve postural stability.

An exploration of the effects of prefabricated and customized insoles on lower limb kinetics and kinematics during walking, stepping up and down tasks: A time series analysis

BACKGROUND

Prefabricated and customized insoles are used in clinical practice to reduce foot pronation. Although data exist on the effects at key points within the stance phase, exploring the impact of different insoles using time series analysis may reveal more detail about their efficacy.

RESEARCH QUESTION

What are the effects revealed by a time series analysis of arch-supported prefabricated insoles (PREFABRICATED) versus arch-supported prefabricated insoles customized with a 6º medial wedge (CUSTOMIZED) on the lower limb biomechanics during walking, stepping up and down tasks in individuals with pronated feet?

METHODS

Nineteen individuals with excessive foot pronation performed walking, stepping up and down tasks using three insoles: CONTROL (flat insole), CUSTOMIZED, and PREFABRICATED. Angles and moments of ankle and knee coronal and hip transverse planes were compared between conditions using statistical parametric mapping (SPM).

RESULTS

For walking, CUSTOMIZED reduced ankle eversion moment compared to CONTROL during midstance and PREFABRICATED during propulsion. CUSTOMIZED decreased KAM during midstance and propulsion compared to PREFABRICATED. Compared to CONTROL, CUSTOMIZED and PREFABRICATED reduced hip internal rotation during propulsion and loading response, respectively. CUSTOMIZED decreased eversion movement during midstance and propulsion for the stepping up task. PREFABRICATED reduced eversion movement during midstance in comparison to CONTROL. For the stepping down task, CUSTOMIZED increased eversion movement during propulsion compared to PREFABRICATED. CUSTOMIZED reduced hip internal rotation angle for stepping up task during propulsion, decreased medial rotation movement during midstance compared to CONTROL, and reduced medial rotation during midstance compared to PREFABRICATED. CUSTOMIZED increased KAM for stepping up and down tasks during propulsion.

SIGNIFICANCE

These findings suggest that both CUSTOMIZED and PREFABRICATED reduce foot pronation. However, non-local effects, such as changes in KAM and hip internal rotation, were seen only in the CUSTOMIZED. Therefore, CUSTOMIZED may be preferable if the objective is to modify the knee and hip mechanics.

The effects of foot orthoses and sensory facilitation on lower limb electromyography: A scoping review

Foot orthoses (FO) are used as a treatment for biomechanical abnormalities, overuse injuries, and neuropathologies, but study of their mechanism remains inconclusive. The neuromotor paradigm has proposed that FOs may manipulate sensory input from foot sole skin to reduce muscle activity for movement optimization. This review argues that a FO likely alters the incoming mechanical stimuli transmitted via cutaneous mechanoreceptors and nociceptors as the foot sole interfaces with the surface of the orthotic. Thus, all FOs with or without intentional sensory facilitation, likely changes sensory information from foot sole cutaneous afferents. Additionally, in light of understanding and applying knowledge pertaining to the cutaneous reflex loop circuitry, FO's increasing sensory input to the motorneuron pool can change EMG to either reflex sign (increase or decrease). The purpose of this scoping review was to synthesize FO and sensory augmentation literature and summarize how FO designs can capitalize on foot sole skin to modulate lower limb electromyography (EMG). Six database searches resulted in 30 FO studies and 22 sensory studies that included EMG as an outcome measure. Results revealed task and phase specific responses with some consistencies in EMG outcomes between testing modalities, however many inconsistencies remain. Electrical stimulation reflex research provides support for a likely sensory-to-motor factor contributing to muscle activity modulation when wearing FOs. The discussion divides trends in FO treatment modalities by desired increase or decrease in each compartment musculature. The results of this review provides a benchmark for future academics and clinicians to advance literature in support of a revised neuromotor paradigm while highlighting the importance of foot sole skin in FO design.

Impact of in shoe and barefoot placed frontal wedges on plantar loading: A systematic review

PURPOSE

The main aim of this review is to report the effect of different types of in-shoe and barefoot wedges on the distribution of the plantar loading of the human foot. We hypothesise that frontal plane wedges modify this parameter.

METHODS

A systematic review was performed, using the PubMed, CINAHL, Prospero and Scopus databases, consulted from their date of first publication to May 2020. Only observational (cross-over studies), randomised controlled trials (RCTs) and quasi-experimental studies addressing the effects of in-shoe and barefoot frontal plane wedges on plantar loading were included. All articles were subjected to quality assessment, using the Newcastle-Ottawa scale for the observational (cross-over) studies, TREND for quasi-experimental studies and the Cochrane Collaboration's tool for the RCTs.

RESULTS

Eleven papers were included in the final review. Four were cross-over studies, other four were quasi-experimental studies and three were RCTs. These eleven studies included 320 patients, with ages ranging from 20 to 60 years. Regarding the risk of bias, most of the observational studies and RCTs had a moderate level of quality.

CONCLUSIONS

The results suggest that lateral wedges are more effective, producing a lateral shift of the centre of pressure and increasing the pressure. Regarding the impact on the peak impact force there seems to be less consensus among the published data.

The effects of foot orthosis and low-dye tape on lower limb joint angles and moments during running in individuals with pes planus

BACKGROUND

Pes Planus or Flat feet is one of the most common lower limb abnormalities. When runners with this abnormality participate in recreational running, interventional therapies could help in pain alleviation and enhance performance. To determine the most effective treatment, however, a biomechanical examination of the effects of each treatment modality is required.

RESEARCH QUESTION

The aim of the present study was to investigate the effects of Foot Orthoses (FOs) and Low-Dye Tape (LDT) on lower limb joint angles and moments during running in individuals with pes planus.

METHODS

kinematic and kinetic data of 20 young people with pes planus were measured during running in three conditions: (1) SHOD (2) with shoes and FOs (3) with shoes and LDT. One-way repeated measure ANOVA was used to investigate the impacts of the FOs and LDT on the lower limb joint angles and moments throughout the stance phase of the running cycle.

RESULTS

The results showed that FOs reduced ankle eversion compared to SHOD and LDT (P < 0.001) and decreased the dorsiflexion angle (P = 0.005) and the plantarflexor moment compared to the SHOD (P < 0.001). FOs increased knee adduction angle (P = 0.021) and knee external rotator moment (P < 0.001) compared to both conditions and increased knee extensor and abductor moments compared to SHOD (P < 0.001). At the hip joint, FOs only increased hip external rotation compared with the LDT condition (P = 0.031); and LDT increased hip extensor moment compared to SHOD and FOs (P = 0.037) and also increased hip adduction angle compared to SHOD (P = 0.037).

SIGNIFICANCE

FOs with a medial wedge appears to increase the external knee adduction moment and knee adduction angles, which are risk factors for the development and progression of knee osteoarthritis. Further, usage of FOs seems to reduce the ankle joint role in propulsion as it impacts the ankle sagittal angles and moments.

A comparison between laterally wedged insoles and ankle-foot orthoses for the treatment of medial osteoarthritis of the knee: A randomized cross-over trial

Objective:

To compare biomechanical and clinical outcome of laterally wedged insoles (LWI) and an ankle-foot orthosis (AFO) in patients with medial knee osteoarthritis.

Design:

Single-centre, block-randomized, cross-over controlled trial.

Setting:

Outpatient clinic.

Subjects:

About 39 patients with symptomatic medial knee osteoarthritis.

Interventions:

Patients started with either LWI or AFO, determined randomly, and six weeks later changed to the alternative.

Main measures:

Change in the 1st maximum of external knee adduction moment (eKAM) was assessed with gait analysis. Additional outcomes were other kinetic and kinematic changes and the patient-reported outcomes EQ-5D-5L, Oxford Knee Score (OKS), American Knee Society Clinical Rating System (AKSS), Hannover Functional Ability Questionnaire – Osteoarthritis and knee pain.

Results:

Mean age (SD) of the study population was 58 (8) years, mean BMI 30 (5). Both aids significantly improved OKS (LWI P = 0.003, AFO P = 0.001), AKSS Knee Score (LWI P = 0.01, AFO P = 0.004) and EQ-5D-5L Index (LWI P = 0.001, AFO P = 0.002). AFO reduced the 1st maximum of eKAM by 18% (P < 0.001). The LWI reduced both maxima by 6% (P = 0.02, P = 0.03). Both AFO and LWI reduced the knee adduction angular impulse (KAAI) by 11% (P < 0.001) and 5% (P = 0.05) respectively. The eKAM (1st maximum) and KAAI reduction was significantly larger with AFO than with LWI (P = 0.001, P = 0.004).

Conclusions:

AFO reduces medial knee load more than LWI. Nevertheless, no clinical superiority of either of the two aids could be shown.

[Insoles, knee braces and ankle-foot orthoses in the treatment of medial gonarthrosis : A literature review]

BACKGROUND

Osteoarthritis is the most common joint disease worldwide and mostly affects the knee joint (gonarthrosis). In treatment algorithms, technical aids in the form of laterally wedged insoles, valgizing knee braces and ankle-foot orthoses have an importance in the treatment of medial unicompartmental knee joint disease. However, national and international guidelines differ in their recommendations.

INSOLES

Taking into account a great amount of scientific work, the measurable effect of laterally wedged insoles appears to be low, so that a justifying indication only exists at low gonarthrosis levels.

KNEE BRACES

Valgizing knee braces have shown stronger biomechanical and clinical effects, but with a slightly increased complication potential and low compliance. Low to medium-grade arthrosis can be treated.

ANKLE-FOOT ORTHOSES

Ankle-foot arthroses have not yet been conclusively examined. Initial work indicates biomechanical and clinical efficacy. The overall effects and indications appear comparable to knee braces, probably with less complication potential.

Effect of a Commercially Available Footwear Insole on Biomechanical Variables Associated With Common Running Injuries

OBJECTIVE

To determine whether Dr. Scholl's Active Series (DSAS) footwear insoles alter biomechanical variables associated with running injuries.

DESIGN

Randomized, controlled experiment.

SETTING

Sport medicine and biomechanics gait analysis laboratory.

PARTICIPANTS

Fifteen healthy adults.

INTERVENTIONS

The control condition was the participant's own athletic footwear. The experimental condition was the participant's own athletic footwear plus a DSAS insole. Participants completed running gait analysis trials with each condition.

MAIN OUTCOME MEASURES

Peak vertical loading rates (VLRs), peak ankle eversion velocities (AEVs), peak ankle eversion angles (AEAs), and knee abduction angular impulses (KAAIs) were calculated and compared between the control and DSAS conditions because these variables have been associated with plantar fasciitis (VLRs), tibial stress syndrome (AEVs, AEAs), and patellofemoral pain syndrome (KAAIs).

RESULTS

Dr. Scholl's Active Series insoles reduced VLRs across participants by 16% (P < 0.001) but had no consistent influence on AEVs, AEAs, or KAAIs. Participant-specific responses showed that most runners either experienced AEA and KAAI reductions or no change with the DSAS insole, whereas AEVs commonly increased with the DSAS insole.

CONCLUSIONS

Dr. Scholl's Active Series insoles demonstrate efficacy in reducing VLRs, which are associated with plantar fasciitis. Biomechanical changes to variables associated with tibial stress syndrome (AEVs, AEAs) and patellofemoral pain syndrome (KAAIs) were inconsistent.

Foot structure and knee joint kinetics during walking with and without wedged footwear insoles

The relationship between static foot structure characteristics and knee joint biomechanics during walking, or the biomechanical response to wedged insoles are currently unknown. In this study, 3D foot scanning, dual X-ray absorptiometry and gait analysis methods were used to determine structural parameters of the foot and assess their relation to knee joint loading and biomechanical response to wedged insoles in 30 patients with knee osteoarthritis. In multiple linear regression models, foot fat content, height of the medial longitudinal arch and static hind foot angle were not associated with the magnitude of the knee adduction moment (R² = 0.24, p = 0.060), knee adduction angular impulse (R² = 0.21, p = 0.099) or 3D resultant knee moment (R² = 0.23, p = 0.073) during gait. Furthermore, these foot structure parameters were not associated with the patients' biomechanical response to medial or lateral wedge footwear insoles (all p < 0.01). These findings suggest that static foot structure is not associated with gait mechanics at the knee, and that static foot structure alone cannot be utilized to predict an individual's biomechanical response to wedged footwear insoles in patients with knee osteoarthritis.

Speed dependent effects of laterally wedged insoles on gait biomechanics in healthy subjects

Laterally wedged insoles have been shown to be effective for the reduction of the knee adduction moment and other biomechanical variables that are associated with the pathogenesis of knee osteoarthritis. However, inconclusive results such as adverse effects in individual subjects or even no group-wise wedge effects have been presented in different studies and it has been suggested to identify variables that potentially confound the wedge effect. The main objective of this study was the investigation of interaction effects of lateral wedges with walking speed, as different self-selected speeds have mainly been used in previous studies. Twenty-two healthy subjects completed gait analysis trials on an instrumented treadmill. They walked in different speed conditions (0.9, 1.1, 1.3, 1.5m/s) with a neutral and a laterally wedged insole. Kinematics were acquired using infrared cinematography with reflective markers attached to the lower body. From the stance phase we extracted biomechanical parameters that are associated with knee joint loading and osteoarthritis severity. No interaction effect of lateral wedges and speed was observed for most biomechanical parameters except for the ankle eversion range of motion. The main effects of wedges were reductions of the external knee adduction moment and of the knee adduction angular impulse. All biomechanical variables changed with increasing speed. Only the lateral offset of the center of pressure did not respond to wedge or to speed changes. Our results suggest that different self-selected speeds do not confound the effect of laterally wedged insoles.

Biomechanics in dermatology: Recent advances and future directions

Biomechanics is increasingly being recognized as an important research area in dermatology. To highlight only a few examples, biomechanics has contributed to the development of novel topical therapies for aesthetic and medical purposes, enhanced our understanding of the pathogenesis of plantar melanoma, and provided insight into the epidemiology of psoriatic disease. This article summarizes the findings from recent studies to demonstrate the important role that biomechanics may have in dermatologic disease and therapy and places these biomechanical findings in a clinical context for the practicing physician. In addition, areas for future biomechanics research and development in dermatology are discussed.

A three dimensional approach for quantifying resultant loading at the knee

BACKGROUND

Clinical effectiveness of lateral wedges for knee osteoarthritis is inconsistent across studies. One explanation is that knee loading is not fully described by the peak frontal-plane knee moment. The purpose of this study was to propose a 3D resultant approach to describing moments at the knee and evaluate how this moment changes in response to lateral wedges.

METHODS

Walking gait analysis was performed on 20 individuals with knee osteoarthritis, in their own shoes, with and without a six millimeter lateral wedge insole. Frontal-plane and 3D resultant moments were calculated for each participant and footwear condition. Paired t-tests identified differences between footwear conditions, correlations identified relationships between frontal-plane and 3D resultant moments, and regressions assessed relationships between moments and pain.

RESULTS

Significant reductions to peak frontal-plane moments (p=0.001) and 3D resultant moments at the same time point (p=0.042) were observed with lateral wedges. While an overall significant correlation was observed between change in frontal-plane moments and change in 3D resultant moments with a lateral wedge (r=0.68, p=0.001), 5/20 participants experienced disparate results where the frontal-plane moment was reduced yet the 3D moment increased.

CONCLUSIONS

While lateral wedges alter frontal-plane moment magnitude, the direction of change does not always correspond to the direction of change observed in the 3D resultant moment. Thus resultant knee load may sometimes increase with lateral wedges.

CLINICAL RELEVANCE

Future prospective studies should evaluate if changes in 3D resultant moments, and thus total knee load, offer an explanation as to why some participants do not experience clinical benefit from lateral wedges.