Preliminary investigation on the reduction of plantar loading pressure with different insole materials (SRP--Slow Recovery Poron, P--Poron, PPF--Poron +Plastazote, firm and PPS--Poron+Plastazote, soft)

Biomimetic Orthopedic Footwear Advanced Insole Materials to Be Used in Medical Casts for Weight-Bearing Monitoring

Fabrication, characterization and testing of protective biomimetic orthopedic footwear advanced insole materials are introduced. The main objective of this material is to preserve and isolate a set of sensors for the Weight-Bearing Monitoring System (WBMS) device. Twenty-one samples of renewably sourced Polyurethane Foam (PUF) composed of poly(trimethylene ether) glycol (PO3G) and unmodified castor oil (CO) were synthesized and evaluated according to predetermined criteria. Response surface methodology of Box-Behnken design was applied to study the effect of the polyols ratio, isocyanate index (II), and blowing agent ratio on the properties (hardness, density) of PUFs. Results showed that CO/PO3G/Tolyene Diisocyanate (TDI) PUFs with hardness Shore A 17-22 and density of 0.19-0.25 g/cm3 demonstrate the required characteristics and can potentially be used as a durable and functional insole material. Phase separation studies have found the presence of well-segregated structures in PUFs having polyols ratio of CO:PO3G 1:3 and low II, which further explains their extraordinary elastic properties (400% elongation). Analysis of cushioning performance of PUF signified that five samples have Cushioning Energy (CE) higher than 70 N·mm and Cushioning Factor (CF) in the range of 4-8, hence are recommended for application in WBMS due to superior weight-bearing and pressure-distributing properties. Moreover, the developed formulation undergoes anaerobic soil bacterial degradation and can be categorized as a "green" bio-based material.

Novel 3D-printed foot orthoses with variable hardness: A comfort comparison to traditional orthoses

Custom foot orthoses are used to treat a variety of foot pathologies. However, orthotic production requires significant hands-on fabrication time and expertise to produce orthoses that are both comfortable and effective. This paper introduces a novel 3D printed orthosis and fabrication method that utilizes custom architectures to produce variable-hardness regions. These novel orthoses are compared to traditionally fabricated orthoses during a 2-week user comfort study. Twenty (n = 20) male volunteers underwent orthotic fitting for both traditional and 3D-printed foot orthoses prior to engaging in treadmill walking trials and 2 weeks of wear. Each participant undertook a regional comfort, acceptance, and comparison analysis of the orthoses at three time points throughout the study (0, 1, and 2 weeks). Both the 3D-printed and the traditionally fabricated foot orthoses demonstrated statistically significant increases in comfort when compared to the factory fabricated shoe insert. Additionally, the two orthosis groups were not significantly different from each other in comfort rankings both regionally and overall at any time point. The similar comfort achieved by the 3D-printed orthosis to the traditionally fabricated orthosis after 7 days and 14 days emphasizes the potential of the future use of the more reproducible and adaptable 3D-printed orthosis manufacturing methodology.

Influence of Contoured Insoles with Different Materials on Kinematics and Kinetics Changes in Diabetic Elderly during Gait

BACKGROUND

Alterations in the lower limb kinematics and kinetics of diabetic patients have been reported in previous studies. Inappropriate choices of orthopedic insole materials, however, fail to prevent diabetic foot ulcers and modify abnormal gait. The aim of this study was to quantitatively compare the effects of contoured insoles with different materials on the kinematics of and kinetics changes in the diabetic elderly during gait.

METHODS

There were 21 diabetic patients who participated in this study. Three-dimensional (3D) experimental contoured insoles constructed of soft (i.e., Nora Lunalastik EVA and PORON^® Medical 4708) and rigid (i.e., Nora Lunalight A fresh and Pe-Lite) materials with Langer Biomechanics longitudinal PPT^® arch pads were adopted. An eight-camera motion capture system (VICON), two force plates, and an insole measurement system-Pedar^® with 99 sensors-were utilized to obtain the kinematics and kinetics data. The plug-in lower body gait model landmarks were used for dynamic data acquisition during gait. The corresponding data from five gait cycles were selected and calculated.

RESULTS

The range of motions (ROMs) of the ankle joint (p = 0.001) and knee joint (p = 0.044) were significantly influenced when the contoured insoles were worn in comparison to the barefoot condition. The joint moments of the lower limbs with maximum ankle plantarflexion during the loading response and maximum knee and hip flexions were significantly influenced by the use of contoured insoles with different materials in the diabetic elderly. The peak plantar pressure (PPP) of the forefoot (p < 0.001), midfoot (p = 0.009), and rearfoot (p < 0.001) was significantly offloaded by the contoured insoles during the stance phase, whilst the PPP of the rearfoot (p < 0.001) was significantly offloaded during the swing phase.

CONCLUSIONS

The contoured insoles, especially those constructed with soft materials, significantly offloaded the PPP during gait-hence accommodating certain abnormal gait patterns more effectively compared to going barefoot.

Effects of contoured insoles with different materials on plantar pressure offloading in diabetic elderly during gait

To investigate the effect of contoured insoles constructed of different insole materials, including Nora Lunalastik EVA, Nora Lunalight A fresh, Pe-Lite, and PORON Medical 4708 with Langer Biomechanics longitudinal PPT arch pads on offloading plantar pressure on the foot of the elderly with Type 1 or 2 diabetes during gait. Twenty-two elderly with Type 1 or 2 diabetes participated in the study. Their plantar pressure was measured by using an insole measurement system, while the participants walked 10 m in their bare feet or used each experimental insole in random order. The plantar surface was divided into four specific regions including the toes, forefoot, midfoot, and rearfoot. The mean peak pressure (MPP) and pressure-time integral (PTI) of ten steps with or without wearing one of the four insoles were analyzed on the dominant foot and the four specific plantar regions. After completion of the activities, the participants scored each insole from 1 (the least comfortable) to 10 (the most comfortable). The analysis of variance (ANOVA) factor of the insoles had significant effects on the MPP (P < 0.001) and PTI (P = 0.004) in the dominant foot during gait. Pairwise comparison results showed that the MPP and PTI in the dominant foot were significantly lower (P < 0.001) with PORON Medical 4708 than barefoot, Nora Lunalight A fresh, and Pe-Lite. Additionally, the insole materials had a significant effect for the forefoot (P < 0.001) and rearfoot (P < 0.001) in terms of the MPP and PTI compared with the barefoot condition during gait. Regardless of the plantar region, the MPP and PTI values were the lowest when PORON Medical 4708 was used as the insole material among four insole materials. Meanwhile, a significantly lower MPP and PTI can be found in the forefoot and rearfoot with the use of the four experimental insoles when compared with barefoot. The soft insole materials (i.e., PORON medical 4708 and Nora Lunalastik EVA) had a better performance than the rigid insole materials (i.e., Nora Lunalight A fresh, and Pe-Lite) on plantar pressure offloading for diabetic elderly.

Innovative Medial Cushioning Orthoses Affect Peroneus Longus Electromyographic Activity during Running

Background: Over-supination processes of the foot and ankle involving peroneus longus (PL) damage during running sports have been treated conservatively with passive control tools, such as tapes, braces, or external ankle supports, but the effect of orthoses with typical lateral wedging orthoses (TLWO) on the muscular activity of PL during running remains unclear. Here we investigate the effects of innovative medial cushioning orthoses (IMCO) on PL activity during the full running gait cycle. In addition, we wished to ascertain the effects of innovative medial cushioning orthoses (IMCO) on PL activity during running. Methods: Thirty-one healthy recreational runners (mean age 34.5 ± 3.33) with neutral foot posture index scores, were selected to participate in the present study. They ran on a treadmill at 9 km/h wearing seven different orthoses (NRS, IMCO 3 mm, IMCO 6 mm, IMCO 9 mm, TLWO 3 mm, TLWO 6 mm and TLWO 9 mm), randomly performed on the same day while electromyographic activity of the PL muscle was recorded. Statistical intraclass correlation coefficient (ICC) to test reliability was carried out and the Wilcoxon test with Bonferroni’s correction was developed to analyze the differences between the conditions. Results: the reliability of all assessments showed data higher than 0.81, that is, “almost perfect reliability”; all EMG PL values wearing either TLWO or IMCO showed a statistically significant reduction versus NRS during the fully analyzed running gait cycle; the highest difference was set on NRS 23.08 ± 6.67 to TLWO 9 mm 17.77 ± 4.794 (p < 0.001). Conclusions: Muscular EMG activity of the PL during the full running gait cycle decreases when wearing either TLWO or IMCO relative to NRS; therefore, these orthoses could be prescribed to treat the strain and overload pathologies of PL. In addition, IMCO—as it less thick, compared with TLWO—can be used when aiming to achieve better running economy.

Assessment of a New Lateral Cushioned Casting Orthosis: Effects on Peroneus Longus Muscle Electromyographic Activity During Running

Background:

Classical medial wedge (CMW) orthoses have been prescribed to treat overpronation foot pathologies in runners. The effects of a novel supination orthosis (NSO) on the surface electromyography (EMG) activity of the peroneus longus (PL) muscle during a complete cycle of running have yet to be tested.

Purpose/Hypothesis:

The purpose of this study was to compare the EMG activity of the PL in participants wearing CMW orthoses and NSOs versus neutral running shoes (NRS) during a full cycle of running gait. It was hypothesized that the PL muscle activity would be lower for the NSO compared with CMW or NRS.

Study Design:

Controlled laboratory study.

Methods:

Included were 31 healthy recreational runners of both sexes (14 male and 17 female; mean age, 38.58 ± 4.02 years) with a neutral Foot Posture Index and standard rearfoot-strike pattern. Participants ran on a treadmill at 9 km/h while wearing NSO (3-, 6-, and 9-mm thicknesses), CMW (3-, 6-, and 9-mm thicknesses), and NRS, for a total of 7 different conditions randomly selected, while the EMG signal activity of the PL was recorded for 30 seconds. Each trial was recorded 3 times, and the intraclass correlation coefficient (ICC) to test reliability of the measurements was calculated. The Wilcoxon pair to pair nonparametric test with Bonferroni correction was performed to analyze differences among the conditions.

Results:

The reliability of all assessments was almost perfect (ICC, >0.81). For both the CMW and NSO, regardless of thickness, the PL activity was statistically significantly lower compared with the NRS (P < .05 for all). For all CMW thicknesses, the PL activity was lower compared with the respective NSO thicknesses, with the 3-mm thickness having the largest difference (CMW_3mm, 18.63 ± 4.64 vs NSO_3mm, 20.78 ± 4.99 mV; P < .001).

Conclusion:

Both CMW and NSO produced reduced EMG activity of the PL muscle; therefore, they can be prescribed to treat overpronation pathologies without associated PL strain concerns. In addition, the NSO saved the enhancement material placed on the medial-rear side of CMW, making it easier to wear sports shoes.

Clinical Relevance:

Knowing the safety of CMW and NSO will aid in understanding treatments for overpronation pathologies.

Mechanics of foot orthotics: material properties

Orthotics have been utilised by clinicians for many years to treat foot-related abnormalities. With advancements in material sciences, the footwear industry started utilising synthetic materials which have better and suitable properties. Clinicians, who prescribe foot insoles, need to have an extensive understanding of the properties and characteristics of insole materials, to make informed decisions to meet the patients' needs. This thesis showcases utilised techniques and systems to evaluate orthosis properties as well as current criteria to date. Researchers have utilised a variety of testing techniques to examine properties of insole materials including; bench testing, simulated in-shoe conditions, in-shoe testing, and finite element analysis. Even though, there is a great understanding of material properties with endless diverse composition and thicknesses of each material makes clinical recommendations on the choice of material an impossible task. As the footwear orthosis industry shifts the focus from material to design, some researchers explore various anisotropic materials to create a homogeneous insole that can support as well as relieve pressure on patient's feet.

Effect of different orthotic materials on plantar pressures: a systematic review

Background

The effect of different orthotic materials on plantar pressures has not been systematically investigated. This study aimed to review and summarise the findings from studies that have evaluated the effect of orthotic materials on plantar pressures.

Methods

We conducted a systematic review of experimental studies that evaluated the effect of foot orthotic materials or shoe insole materials on plantar pressures using in-shoe testing during walking. The following databases were searched: MEDLINE, CINAHL, Embase and SPORTDiscus. Included studies were assessed for methodological quality using a modified Quality Index. Peak pressure, pressure-time integral, maximum force, force-time integral, contact area, and contact time were variables of interest. Data were synthesised descriptively as studies were not sufficiently homogeneous to conduct meta-analysis. Standardised mean differences (Cohen’s d) were calculated to provide the size of the effect between materials found in each study.

Results

Five studies were identified as meeting the eligibility criteria. All five studies were laboratory-based and used a repeated measures design. The quality of the studies varied with scores ranging between 20 and 23 on the modified Quality Index (maximum index score 28). The included studies investigated the effects of polyurethane (including PORON®), polyethylene (including Plastazote®), ethyl vinyl acetate (EVA) and carbon graphite on plantar pressures. Polyurethane (including PORON®), polyethylene (including Plastazote®) and EVA were all found to reduce peak pressure.

Conclusion

Based on the limited evidence supplied from the five studies included in this review, some orthotic materials can reduce plantar pressures during walking. Polyurethane (including PORON®), polyethylene (including Plastazote®) and EVA reduce peak pressure beneath varying regions of the foot. Future well-designed studies will strengthen this evidence.

The Effectiveness of Personalized Custom Insoles on Foot Loading Redistribution during Walking and Running

The objective of this study was to investigate the effectiveness of different hardness of personalized custom insoles on plantar pressure redistribution in healthy young males during walking and running. Six males participated in the walking and running test (age: 24±1.6 years, weight: 67.9±3.6 kg, height: 175.5±4.7 cm). All subjects were instructed to walk and run along a 10m pathway wearing two different hardness insoles (i.e., hard custom insoles (CHI) and soft custom insole (CSI)) and control insole (CI) at their preferred speed. Peak pressure, mean pressure, maximum force, pressure-time integral were collected to analyze using SPSS. The plantar pressure of forefoot and medial midfoot were significantly increased and of lateral forefoot and lateral midfoot were decreased by both kinds of custom insoles in running tests. While the CHI significantly increased plantar pressure of the medial forefoot compared with the CSI and CI both in walking and running tests. The custom insoles showed significantly higher plantar pressure on medial midfoot. But CSI seems better than CHI because of redistributing the plantar pressure by increasing the plantar pressure of whole forefoot. Moreover, CSI showed significantly lower plantar pressure than CI and CHI at lateral midfoot during running test. The CHI causes significant high pressure at medial forefoot (MF), which may raise the risk of forefoot pain.

Effectiveness and Duration of Plantar Pressure Off-loading by Two Designs of Felt Padding: A Preliminary Study

BACKGROUND

The aim of this study was to observe the pressure changes in the felt padding used to off-load pressure from the first metatarsal head, the effects obtained by different designs, and the loss of effectiveness over time.

METHOD

With a study population of 17 persons, two types of 5-mm semicompressed felt padding were tested: one was C-shaped, with an aperture cutout at the first metatarsophalangeal joint, and the other was U-shaped. Pressures on the sole of the foot were evaluated with a platform pressure measurement system at three time points: before fitting the felt padding, immediately afterward, and 3 days later.

RESULTS

In terms of decreased mean pressure on the first metatarsal, significant differences were obtained in all of the participants (P < .001). For plantar pressures on the central metatarsals, the differences between all states and time points were significant for the C-shaped padding in both feet (P < .001), but with the U-shaped padding the only significant differences were between no padding and padding and at day 3 (P = .01 and P = .02).

CONCLUSIONS

In healthy individuals, the U-shaped design, with a padding thickness of 5 mm, achieved a more effective and longer-lasting reduction in plantar pressure than the C-shaped design.

Foot care in epidermolysis bullosa: evidence-based guideline

This guideline was designed to provide service providers and users with an evidence-based set of current best practice guidelines for people and their families and carers, living with epidermolysis bullosa (EB). A systematic literature review relating to the podiatric care of patients with EB was undertaken. Search terms were used, for which the most recent articles relating to podiatric treatment were identified from as early as 1979 to the present day, across seven electronic search engines: MEDLINE, Wiley Online Library, Google Scholar, Athens, ResearchGate, Net and PubFacts.com. The Scottish Intercollegiate Guidelines Network (SIGN) methodology was used. The first guideline draft was analysed and discussed by clinical experts, methodologists and patients and their representatives at four panel meetings. The resulting document went through an external review process by a panel of experts, other healthcare professionals, patient representatives and lay reviewers. The final document will be piloted in three different centres in the U.K. and Australia. Following an EB community international survey the outcomes indicated six main areas that the community indicated as a priority to foot management. These include blistering and wound management, exploring the most suitable footwear and hosiery for EB, management of dystrophic nails, hyperkeratosis (callus), maintaining mobility and fusion of toes (pseudosyndactyly). The evidence here is limited but several interventions currently practised by podiatrists show positive outcomes.

INSoles To Ease Pressure (INSTEP) Study: a multicentre, randomised controlled feasibility study to compare the effectiveness of a novel instant optimised insole with a standard insole for people with diabetic neuropathy: a study protocol

INTRODUCTION

Foot ulceration is a multifactorial complication of diabetes. Therapeutic insoles and footwear are frequently used to reduce elevated tissue pressures associated with risk of foot ulceration. A novel protocol using in-shoe pressure measurement technology to provide an instant optimised insole and house shoe solution has been developed, with the aim of reducing foot ulceration.

AIM

This study aims to assess the feasibility of conducting a multicentre randomised controlled trial to compare the effectiveness of a novel instant optimised insole with a standard insole for people with diabetic neuropathy.

METHODS AND ANALYSIS

This study is a participant and assessor blinded, randomised, multicentre parallel group feasibility trial with embedded qualitative study. Seventy-six participants will be recruited from three podiatry clinics and randomised to an optimised insole plus usual care (intervention group) or standard insole plus usual care (control group) using a minimisation by randomisation procedure by study centre and previous ulcer status. Assessment visits and data collection will be at baseline, 3 months, 6 months and 12 months. Feasibility and acceptability of the trial procedures will be determined in terms of recruitment and retention rates, data completion rates, intervention adherence and effectiveness of the blinding.Assessment of the appropriateness and performance of outcome measures will inform selection of the primary and secondary outcomes and sample size estimate for the anticipated definitive randomised controlled trial. Clinical outcomes include incidence of plantar foot ulceration and change in peak plantar pressure. Twelve participants (four from each centre) and three treating podiatrists (one from each centre) will be interviewed to explore their experiences of receiving and delivering the intervention.

ETHICS AND DISSEMINATION

The study was approved by the South-West Exeter Research Ethics Committee. Findings will be disseminated through conference presentations, public platforms and academic publications.

TRIALS REGISTRATION NUMBER

ISRCTN16011830; Pre-results.

Factors affecting insole usage in patients with Pes planus

Abstract: Introduction: Insoles and exercise programs are the main treatment methods for pes planus patients. Insole using may prevent the formation of pain in daily activities as well as increasing the quality of walking. The aim of this study was to investigate insole usage time and the factors affecting this situation in patient with pes planus. Materials and Methods: 136 patients with pes planus who were prescribed an insole, included in the study. We invited patients to participate in a telephone survey. Patients' demographics, insole usage time, reasons to quit and the quitting time were questioned. Insole usage rates and the demographic data of patients were compared. Results: Of the 136 patients included in the present study, 80 were women (59%) and 56 were male (31%). 86 of these patients used an insole six months and over, 15 of them used shorter than six months and 35 of them bought the insoles but they didn't use it (63%, 11% and 26% respectively ). The average age of patients who used insoles was 32.80 ± 18.14 and who did not use insoles was 40.77 ± 12.54 (p = 0.04). 33.8 percent of women and 14.3 percent of men did not use insoles. This difference is statistically significant (p = 0.04). We did not find any significant relationship between height, weight, body mass index values and usage of insoles (p > 0:05). Conclusion: The use of insoles in treating patients with pes planus is widely accepted and may be affected by the demographics such as gender and age. Besides wearing comfort, female sex and older age should be considered that may affect the use of insoles.

Footwear and insole design features to prevent foot ulceration in people with diabetes: a systematic review protocol

REVIEW QUESTION/OBJECTIVE

The aim of this systematic review is to identify the key design features of footwear and insoles that are used to offload the plantar surface of the foot to prevent foot ulceration in adults with diabetes.More specifically, the objectives are to identify the key design features of footwear and insoles to offload the plantar surface of the foot with regard to.

The Applicability of Plantar Padding in Reducing Peak Plantar Pressure in the Forefeet of Healthy AdultsImplications for the Foot at Risk

BACKGROUND

We investigated the effectiveness and durability of two types of plantar padding, the plantar metatarsal pad and the single wing plantar cover, which are commonly used for reducing forefoot plantar pressures.

METHODS

Mean peak plantar pressure and impulse at the hallux and at the first, second, third, and fourth metatarsophalangeal joints across both feet were recorded using the two-step method in 18 individuals with normal asymptomatic feet. Plantar paddings were retained for 5 days, and their durability and effectiveness were assessed by repeating the foot plantar measurement at baseline and after 3 and 5 days.

RESULTS

The single wing plantar cover devised from 5-mm felt adhesive padding was effective and durable in reducing peak plantar pressure and impulse at the first metatarsophalangeal joint (P = .001 and P = .015, respectively); however, it was not found to be effective in reducing peak plantar pressure and impulse at the hallux (P = .782 and P = .845, respectively). The plantar metatarsal pad was not effective in reducing plantar forefoot pressure and impulse at the second, third, and fourth metatarsophalangeal joints (P = .310 and P = .174, respectively).

CONCLUSIONS

These results imply limited applicability of the single wing plantar cover and the plantar metatarsal pad in reducing hallux pressure and second through fourth metatarsophalangeal joint pressure, respectively. However, the single wing plantar cover remained durable for the 5 days of the trial and was effective in reducing the peak plantar pressure and impulse underneath the first metatarsophalangeal joint.

THE INFLUENCE OF SLOW RECOVERY INSOLE ON PLANTAR PRESSURE AND CONTACT AREA DURING WALKING

Plantar pressure assessment is commonly used as a tool to assess the efficacy of insoles in reducing the risk of mechanical trauma to the plantar soft tissue during walking gait. The slow rebound (SR) Poron insole is intended to provide a custom fit to the foot and is believed to be superior in increasing the contact area and consequently reducing the contact pressure compared to a normal Poron (NP) insole. The aim of this study was to compare the effectiveness of SR or NP versus an ethylene vinyl acetate (EV) insole in increasing the contact area (CA), and in reducing the contact pressure (CP) at different regions of the foot during walking. Plantar pressure data was collected from nine healthy individuals during walking using commercially available in-shoe plantar pressure sensors. Although, the NP insole significantly increased the CA and decreased the CP on the entire foot compared to the EV, there was no significant change in CP or CA at any region of the foot in any of the tested insoles. CP showed a positive significant correlation with CA at heel, hallux and heel center in all three insoles. The expected significant negative correlation between regional CA and CP was not observed.

FOOT LOADING PATTERNS WITH DIFFERENT UNSTABLE SOLES STRUCTURE

Foot loading patterns can be changed by using different unstable sole structures, detailed quantification of which is of great significance for research and technological development in falling prevention and lower limb disorders rehabilitation. In this study, unstable soles constructions are adjusted through unstable elements in heel and medial, neutral and lateral forefoot and the foot loading patterns are comparatively studied. A total of 22 healthy male subjects participated in this test. Subjects are asked to walk over a 12 m walkway with control shoes and experimental shoes in self-adapted speed. Significant peak pressure, contact area and pressure-time integral differences in middle foot are found between control shoes and experimental shoes. In addition, peak pressure and pressure-time integral are found to increase significantly with unstable elements adding to center forefoot. The results showed that adjusting the unstable elements in coronal plane of forefoot could effectively alter the distribution of plantar pressure, this could potentially offer a mechanism for preventing falling of elderly and rehabilitation of lower extremity malfunctions. This study also demonstrates a novel concept that unstable element could be effectively adjusted in terms of position to meet different functional requirement.

PLANTAR PRESSURE DISTRIBUTION CHARACTER IN YOUNG FEMALE WITH MILD HALLUX VALGUS WEARING HIGH-HEELED SHOES

Young females with mild hallux valgus (HV) have been identified as having an increased risk of first ray deformation. Little is known, however, about the biomechanical changes that might contribute to this increased risk. The purpose of this study was to compare kinetics changes during walking for mild HV subjects with high-heel-height shoes. Twelve female subjects (six with mild HV and six controls) participated in this study with heel height varying from 0 cm (barefoot) to 4.5 cm. Compared to healthy controls, patients had significantly higher peak pressure on the big toe area during barefoot walking. When the heel height increased, loading was transferred to medial side of the forefoot, and the big toe area suffered more impact compared to barefoot in mild HV. This study also demonstrated that the center of pressure (COP) inclines to medial side alteration after high-heeled shoes wearing. These findings indicate that mild HV people should be discouraged from wearing high-heeled shoes.

HUMAN RECOGNITION BASED ON PLANTAR PRESSURE PATTERNS DURING GAIT

Recognizing individuals by their gait is a new biometric methodology, which employs dynamic features derived from tracking gait. Instead of the image processing techniques used in most existing studies, our previous study initialized the work of investigating gait recognition in terms of biomechanics. The experimental results showed that the angles and forces of the lower limb joints were reliable features for recognition of individuals, which can provide us with a considerable amount of information in the field of computer science and thus help in developing a more efficient recognition method, which is also more computationally efficient than current image processing methods. Encouraged by the early results, in this study, we proposed a people recognition method based on plantar pressure patterns, which can be used in a concealed manner. We hoped to prove the feasibility of using foot pressure for individual recognition.

Two different plantar pressure parameter measurement schemes are discussed: (1) the characteristic parameters and (2) the pressure values of each sensor cell in each frame. The self-organizing map (SOM) neuron network algorithm was used in both schemes for data classification. In order to improve the recognition rate, a support vector machine (SVM) was used as the data classification algorithm for the all-sensor-values method. High recognition rates were achieved with the second method, i.e., using all the sensor cell values of the foot pressure pattern during walking, regardless of the algorithm used. It is suggested that the foot pressure distribution of gait is a suitable feature for gait recognition. Both SOM and SVM can be feasible classifiers for foot pressure-based features.

A pilot study to assess the effectiveness of orthotic insoles on the reduction of plantar soft tissue strain

BACKGROUND

Plantar ulcers pose a frequent serious complication in the neuropathic foot. Previous studies suggested that ulcer initiation occurs within the plantar soft tissue rather than on the plantar surface. This study investigated the effectiveness of different shaped silicone insoles on the reduction of both plantar soft tissue strain and pressure. The authors have found no previous experimental studies on the effectiveness of insole shape on reducing plantar soft tissue strain during standing.

METHODS

A custom molded silicone insole which allowed passage of ultrasound to the plantar surface of the foot was prototyped for this study. Soft tissue strain was computed from soft tissue thickness measured using ultrasound in five conditions: unloaded, barefoot, wearing a prefabricated silicone insole, wearing the custom molded silicone insole alone then with a metatarsal pad. Plantar pressure was measured for the same conditions.

FINDINGS

The custom molded insole was found to significantly reduce soft tissue strain and plantar pressure relative to both the barefoot condition and the prefabricated insole under the second and third metatarsal heads. The metatarsal pad was found to significantly reduce soft tissue strain but not significantly affect plantar pressure.

INTERPRETATION

A custom molded silicone insole can effectively reduce both soft tissue strain and plantar pressure and is thus preferable to a prefabricated insole. It is suggested that quantifying the reduction of soft tissue strain is an essential design requirement for orthotic insoles since plantar pressure may not be a sufficient indicator of the effectiveness of an insole in preventing ulcer initiation.

THE EFFECTS OF DRESS SHOES ON STABILITY DURING QUIET STANDING AND ENERGY CONSUMPTION WHILE WALKING

Footwear is an extremely important clothing item worn by all individuals. Currently, there is insufficient research regarding the influence of dress shoes on standing stability and energy consumption while walking. Therefore, the aim of this study was to evaluate the influence of dress shoes on the performance of normal subjects based on stability and energy consumption analysis. Fifteen normal subjects were recruited in this research study to stand and walk with and without shoes. The stability of the subjects in quiet standing was measured by the use of a force plate based on center of pressure (COP) sway. The energy consumption was evaluated by a heart rate monitoring system (Polar Electro) based on the physiological cost index (PCI). The mean values of PCI while walking with and without shoes were 0.29 ± 0.117 and 0.265 ± 0.112 beats/m, respectively (p-value > 0.05). The amplitudes of COP sways in the mediolateral and anteroposterior directions were 10.4 ± 3.5 and 25 ± 6.92 mm while standing with shoes and 9.3 ± 2.84 and 22.5 ± 5.25 mm in barefoot standing, respectively (p-value > 0.05). It can be concluded that wearing dress shoes does not influence the performance of subjects while standing or walking.

Effect of heating on the mechanical properties of insole materials

BACKGROUND

The most common method of customizing shoe insoles to the shape and surface of the foot is to heat and then mold the materials. The effect of heating on the mechanical properties of these materials is unknown.

METHODS

The properties of individual and common combinations of insole materials were tested before and after heating. Individual materials tested were soft Plastazote (SP), medium Plastazote (MP), Puff (F), and Nickelplast (N); combinations of materials that were tested were SP + F and MP + F, each with and without Poron (P). Three samples of each were tested five times. Materials were heated and then compressed with an MTS servohydraulic device. Load transmission and percent compression at maximal load were measured on single materials and their combinations. Stress-strain curves were measured.

RESULTS

Compared to unheated material, the heated material transmitted higher forces. After heating, the combinations transmitted maximal load at a lower percentage of compression (i.e., became stiffer). Heating also changed the stress-strain curves of the three-material combinations, causing them to transmit maximal pressure at a lower strain.

CONCLUSION

Heating insole materials changed their mechanical properties. The materials became stiffer and less effective in the attenuation of applied forces.

CLINICAL RELEVANCE

The common practice of heating insole materials to improve their contact with the foot reduced the pressure-reducing properties of the materials, which may decrease their clinical effectiveness.

Effect of insole material on lower limb kinematics and plantar pressures during treadmill walking

BACKGROUND

Currently there is a paucity of research providing recommendations on the type of orthotic or material used in its construction for different patient requirements.

OBJECTIVES

To gain a greater understanding of the characteristics of orthotic materials and how they affect gait so to enhance the clinical decision-making process.

STUDY DESIGN

Repeated measures.

METHODS

Plantar pressures and kinematics were evaluated for 10 participants while walking on a treadmill under various conditions which included, shoes only and shoes with four different flat insoles and custom devices created in each of two densities of two materials.

RESULTS

For the flat insoles, medium density ethyl vinyl acetate was found to produce greater peak pressures than at least one of the other material conditions and low and medium density polyurethane were most effective at increasing average contact area and at reducing pressure time integral. For the custom devices, while no significant differences were evident, when compared to the shoe only condition, medium density polyurethane increased average contact area by a greater percentage than the other materials.

CONCLUSIONS

Results for medium density polyurethane suggest a possible difference in loading characteristics, indicating a potential material suitability for patients with a compromised ability to deal with pressure.