A new ambulatory foot pressure device for patients with sensory impairment. A system for continuous measurement of plantar pressure and a feed-back alarm

In-shoe plantar pressure measurement technologies for the diabetic foot: A systematic review

Introduction

Loss of cutaneous protective sensation and high plantar pressures increase the risk for diabetic foot patients. Trauma and ulceration are imminent threats, making assessment and monitoring essential. This systematic review aims to identify systems and technologies for measuring in-shoe plantar pressures, focusing on the at-risk diabetic foot population.

Methods

A systematic search was conducted across four electronic databases (Scopus, Web of Science, PubMed, Oxford Journals) using PRISMA methodology, covering articles published in English from 1979 to 2024. Only studies addressing systems or sensors exclusively measuring plantar pressures inside the shoe were included.

Results

A total of 87 studies using commercially available devices and 45 articles proposing new systems or sensors were reviewed. The prevailing market offerings consist mainly of instrumented insoles. Emerging technologies under development often feature configurations with four, six or eight resistive sensors strategically placed within removable insoles. Despite some variability due to the inherent heterogeneity of human gait, these devices assess plantar pressure, although they present significant differences between them in measurement results. Individuals with diabetic foot conditions appears exhibit elevated plantar pressures, with reported peak pressures reaching approximately 1000 kPa. The results also showed significant differences between the diabetic and non-diabetic groups.

Conclusion

Instrumented insoles, particularly those incorporating resistive sensor technology, dominate the field. Systems employing eight sensors at critical locations represent a pragmatic approach, although market options extend to systems with up to 960 sensors. Differences between devices can be a critical factor in measurement and highlights the importance of individualized patient assessment using consistent measurement devices.

In-shoe pressure thresholds for people with diabetes and neuropathy at risk of ulceration: A systematic review

INTRODUCTION

In-shoe pressure thresholds play an increasingly important role in the prevention of diabetes-related foot ulceration (DFU). The evidence of their effectiveness, methodological consistency and scope for refinement are the subject of this review.

METHODS

1107 records were identified (after duplicate removal) based on a search of five databases for studies which applied a specific in-shoe pressure threshold to reduce the risk of ulceration. 37 full text studies were assessed for eligibility of which 21 were included.

RESULTS

Five in-shoe pressure thresholds were identified, which are employed to reduce the risk of diabetes-related foot ulceration: a mean peak pressure threshold of 200 kPa used in conjunction with a 25% baseline reduction target; a sustained pressure threshold of 35 mm Hg, a threshold matrix based on risk, shoe size and foot region, and a 40-80% baseline pressure reduction target. The effectiveness of the latter two thresholds have not been assessed yet and the evidence for the effectiveness of the other in-shoe pressure thresholds is limited, based only on two RCTs and two cohort studies.

CONCLUSIONS

The heterogeneity of current measures precludes meta-analysis and further research and methodological standardisation is required to facilitate ready comparison and the further development of these pressure thresholds.

ASSESSING THE POTENTIAL INFLUENCE OF DIFFERENT WALKING STRATEGIES ON PLANTAR PRESSURE DISTRIBUTION TRIGGERED BY A PORTABLE BIOFEEDBACK-BASED GAIT TRAINING DEVICE

Plantar pressure refers to the interfacial contact pressure between the foot and the supporting surface during daily locomotor activities. Information derived from plantar pressure measures is essential in gait and posture research for diagnosing patho-mechanics associated with the musculoskeletal diseases. In particular, it is compulsory to reduce the abnormally high plantar pressure in people with diabetes for the prevention and treatment of foot ulcerations in this population. In this study, a portable biofeedback-based gait training device is developed to advocate able-bodied subjects to adopt different movement patterns in walking to manipulate the plantar pressure distribution under the foot. Through the simultaneous detection of the plantar pressure pattern and the kinematics of the lower extremity joints, it was revealed that the unloading effects for the plantar site in particular to the lateral forefoot subareas were more abundant through biofeedback-assisted gait alterations than the self-awareness control for gait adjustment. In addition, the corresponding relationship between joint coordination and pressure redistribution pattern was obtained, which could potentially be used in gait retraining interventions to correct abnormal plantar pressure patterns in people with diabetes.

The role of foot pressure measurement in the prediction and prevention of diabetic foot ulceration-A comprehensive review

The predominant risk factor of diabetic foot ulcers (DFU), peripheral neuropathy, results in loss of protective sensation and is associated with abnormally high plantar pressures. DFU prevention strategies strive to reduce these high plantar pressures. Nevertheless, several constraints should be acknowledged regarding the research supporting the link between plantar pressure and DFUs, which may explain the low prediction ability reported in prospective studies. The majority of studies assess vertical, rather than shear, barefoot plantar pressure in laboratory-based environments, rather than during daily activity. Few studies investigated previous DFU location-specific pressure. Previous studies focus predominantly on walking, although studies monitoring activity suggest that more time is spent on other weight-bearing activities, where a lower "peak" plantar pressure might be applied over a longer duration. Although further research is needed, this may indicate that an expression of cumulative pressure applied over time could be a more relevant parameter than peak pressure. Studies indicated that providing pressure feedback might reduce plantar pressures, with an emerging potential use of smart technology, however, further research is required. Further pressure analyses, across all weight-bearing activities, referring to location-specific pressures are required to improve our understanding of pressures resulting in DFUs and improve effectiveness of interventions.

A knowledge-based modeling for plantar pressure image reconstruction

It is known that prolonged pressure on the plantar area is one of the main factors in developing foot ulcers. With current technology, electronic pressure monitoring systems can be placed as an insole into regular shoes to continuously monitor the plantar area and provide evidence on ulcer formation process as well as insight for proper orthotic footwear design. The reliability of these systems heavily depends on the spatial resolution of their sensor platforms. However, due to the cost and energy constraints, practical wireless in-shoe pressure monitoring systems have a limited number of sensors, i.e., typically K < 10. In this paper, we present a knowledge-based regression model (SCPM) to reconstruct a spatially continuous plantar pressure image from a small number of pressure sensors. This model makes use of high-resolution pressure data collected clinically to train a per-subject regression function. SCPM is shown to outperform all other tested interpolation methods for K < 60 sensors, with less than one-third of the error for K = 10 sensors. SCPM bridges the gap between the technological capability and medical need and can play an important role in the adoption of sensing insole for a wide range of medical applications.

Diabetic foot infections: state-of-the-art

Foot infections are frequent and potentially devastating complications of diabetes. Unchecked, infection can progress contiguously to involve the deeper soft tissues and ultimately the bone. Foot ulcers in people with diabetes are most often the consequence of one or more of the following: peripheral sensory neuropathy, motor neuropathy and gait disorders, peripheral arterial insufficiency or immunological impairments. Infection develops in over half of foot ulcers and is the factor that most often leads to lower extremity amputation. These amputations are associated with substantial morbidity, reduced quality of life and major financial costs. Most infections can be successfully treated with optimal wound care, antibiotic therapy and surgical procedures. Employing evidence-based guidelines, multidisciplinary teams and institution-specific clinical pathways provides the best approach to guide clinicians through this multifaceted problem. All clinicians regularly seeing people with diabetes should have an understanding of how to prevent, diagnose and treat foot infections, which requires familiarity with the pathophysiology of the problem and the literature supporting currently recommended care.

Real-time human ambulation, activity, and physiological monitoring: taxonomy of issues, techniques, applications, challenges and limitations

Automated methods of real-time, unobtrusive, human ambulation, activity, and wellness monitoring and data analysis using various algorithmic techniques have been subjects of intense research. The general aim is to devise effective means of addressing the demands of assisted living, rehabilitation, and clinical observation and assessment through sensor-based monitoring. The research studies have resulted in a large amount of literature. This paper presents a holistic articulation of the research studies and offers comprehensive insights along four main axes: distribution of existing studies; monitoring device framework and sensor types; data collection, processing and analysis; and applications, limitations and challenges. The aim is to present a systematic and most complete study of literature in the area in order to identify research gaps and prioritize future research directions.

Sensor architectural tradeoff for diabetic foot ulcer monitoring

The diabetic foot complications constitute a tremendous challenge for patients, caregivers, and the healthcare system. Studies show up to 25% of diabetic individuals will develop a foot ulcer during their lifetime and many of these patients eventually must undergo amputation as a result of infection due to untreated foot ulcers. With current technology, in-shoe monitoring systems can be implemented to continuously monitor at-risk ulceration sites based on known indicators such as peak pressure. The important parameters in designing a pressure-sensing insole include the number, location and size of sensors. In this paper, we aim at showing the criticality of sensor architectural tradeoff in developing the in-shoe plantar pressure monitoring systems. We evaluate this tradeoff by using our custom-made platform for data collection during normal walking.

Balance and knee extensibility evaluation of hemiplegic gait using an inertial body sensor network

Background

Most hemiplegic patients have difficulties in their balance and posture control while walking because of the asymmetrical posture and the abnormal body balance. The assessment of rehabilitation of hemiplegic gait is usually made by doctors using clinical scale, but it is difficult and could not be used frequently. It is therefore needed to quantitatively analyze the characteristics of hemiplegic gait. Thus the assessment would be simple, and real-time evaluation of rehabilitation could be carried out.

Methods

Twenty subjects (ten hemiplegic patients, ten normal subjects) were recruited. The subjects walked straight for five meters at their self-selected comfortable speed towards a target line on the floor.

Xsens MTx motion trackers were used for acquiring gestures of body segments to estimate knee joint angles and identify gait cycles. A practical method for data acquisition that does not need to obtain accurate distances between a knee joint and its corresponding sensors is presented.

Results

The results showed that there were significant differences between the two groups in the three nominated angle amplitudes. The mean values of balance level of each parameter in hemiplegic gait and normal gait were: 0.21 versus 0.01, 0.18 versus 0.03, and 0.92 versus 0.03, respectively. The mean values of added angles of each parameter in hemiplegic gait and normal gait were: 74.64 versus 91.31, -76.48 versus −132.4, and 6.77 versus 35.74.

Conclusions

It was concluded that the wearable bio-motion acquisition platform provided a practical approach that was effective in discriminating gait symptoms between hemiplegic and asymptomatic subjects. The extensibility of hemiplegic patients’ lower limbs was significantly lower than that of normal subjects, and the hemiplegic gait had worse balance level compared with normal gait. The effect of rehabilitation training of hemiplegic gait could be quantitatively analyzed.

Biofeedback can reduce foot pressure to a safe level and without causing new at-risk zones in patients with diabetes and peripheral neuropathy

BACKGROUND

Plantar pressure reduction is mandatory for diabetic foot ulcer healing. Our aim was to evaluate the impact of a new walking strategy learned by biofeedback on plantar pressure distribution under both feet in patients with diabetic peripheral neuropathy.

METHODS

Terminally augmented biofeedback has been used for foot off-loading training in 21 patients with diabetic peripheral sensory neuropathy. The biofeedback technique was based on a subjective estimation of performance and objective visual feedback following walking sequences. The patient was considered to have learned a new walking strategy as soon as the peak plantar pressure (PPP) under the previously defined at-risk zone was within a range of 40-80% of baseline PPP in 70% of the totality of steps and during three consecutive walking sequences. The PPP was measured by a portable in-shoe foot pressure measurement system (PEDAR(®)) at baseline (T0), directly after learning (T1) and at 10-day retention test (T2).

RESULTS

The PPP under at-risk zones decreased significantly at T1 (165 ± 9 kPa, p < 0.0001) and T2 (167 ± 11, p = 0.001), as compared with T0 (242 ± 12 kPa) without any increase of the PPP elsewhere. At the contralateral foot (not concerned by off-loading), the PPP was slightly higher under the lateral midfoot at T1 (68 ± 8 kPa, p = 0.01) and T2 (65 ± 8 kPa, p = 0.01), as compared with T0 (58 ± 6 kPa).

CONCLUSIONS

The foot off-loading by biofeedback leads to a safe and regular plantar pressure distribution without inducing any new 'at-risk' area under both feet.

A low-cost body inertial-sensing network for practical gait discrimination of hemiplegia patients

Gait analysis is widely used in detecting human walking disorders. Current gait analysis methods like video- or optical-based systems are expensive and cause invasion of human privacy. This article presents a self-developed low-cost body inertial-sensing network, which contains a base station, three wearable inertial measurement nodes, and the affiliated wireless communication protocol, for practical gait discrimination between hemiplegia patients and asymptomatic subjects. Every sensing node contains one three-axis accelerometer, one three-axis magnetometer, and one three-axis gyroscope. Seven hemiplegia patients (all were abnormal on the right side) and 7 asymptomatic subjects were examined. The three measurement nodes were attached on the thigh, the shank, and the dorsum of the foot, respectively (all on the right side of the body). A new method, which does not need to obtain accurate positions of the sensors, was used to calculate angles of knee flexion/extension and foot in the gait cycle. The angle amplitudes of initial contact, toe off, and knee flexion/extension were extracted. The results showed that there were significant differences between the two groups in the three angle amplitudes examined (-0.52±0.98° versus 6.94±2.63°, 28.33±11.66° versus 47.34±7.90°, and 26.85±8.6° versus 50.91±6.60°, respectively). It was concluded that the body inertial-sensing network platform provided a practical approach for wearable biomotion acquisition and was effective for discriminating gait symptoms between hemiplegia and asymptomatic subjects.

Biofeedback for foot offloading in diabetic patients with peripheral neuropathy

AIMS

The reduction of high plantar pressure in diabetic patients with peripheral neuropathy is mandatory for prevention of foot ulcers and amputations. We used a new biofeedback-based method to reduce the plantar pressure at an at-risk area of foot in diabetic patients with peripheral neuropathy.

METHODS

Thirteen diabetic patients (age 60.8 +/- 12.3 years, body mass index 29.0 +/- 5.0 kg/m(2)) with peripheral neuropathy of the lower limbs were studied. Patients with memory impairment were excluded. The portable in-shoe foot pressure measurement system (PEDAR) was used for foot offloading training by biofeedback. The learning procedure consisted in sequences of walking (10 steps), each followed by a subjective estimation of performance and objective feedback. The goal was to achieve three consecutive walking cycles of 10 steps, with a minimum of seven steps inside the range of 40-80% of the baseline peak plantar pressure. The peak plantar pressure was assessed during the learning period and at retention tests.

RESULTS

A significant difference in peak plantar pressure was recorded between the beginning and the end of the learning period (when the target for plantar pressure was achieved) (262 +/- 70 vs. 191 +/- 53 kPa; P = 0.002). The statistically significant difference between the beginning of learning and all retention tests persisted, even at the 10-day follow-up.

CONCLUSIONS

Terminal augmented feedback training may positively affect motor learning in diabetic patients with peripheral neuropathy and could possibly lead to suitable foot offloading. Additional research is needed to confirm the maintenance of offloading in the long term.

Diabetic foot disease in the elderly

Elderly diabetic patients are particularly burdened by foot disease. The main causes for foot disease are peripheral neuropathy, foot deformities and peripheral arterial disease (PAD). Other risk factors include poor vision, gait abnormalities, reduced mobility an medical co-morbidities. The risk of major amputations increases with age, along with the increased prevalence of these risk factors. Th true risk of amputation and other burdens of foot disease in the elderly are likely underestimated by current epidemiological data. Th prevalence of neuropathy, foot deformities and PAD as well as the risk of amputation all increase with age even in non-diabetic patients. The principles of prevention and management of diabetic foot disease may also apply to large segments of the elderly non-diabetic population. Foot ulcer prevention relies on the identification of high risk patients and avoidance of triggering events, such as ill-fitting shoes, walking barefoot or poor self-care. PAD is a major cause of amputation and should be prevented by lifelong attention to glycaemic control, treatment of hypertension and dyslipidemia, and avoidance of smoking. The treatment of foot ulcers relies on pressure relief (off-loading), wound debridement, and treatment of infection and ischemia. It requires an individualized approach considering the patient's co-morbidities and functional status. Off-loading remains essential, but devices such as total contact casts or crutches can only rarely be implemented. However, providing adapted standard foot-wear and insisting on its consistent use even at home is often effective. The benefits of aggressive vascular or orthopaedic surgery should be weighed against the risks of prolonged hospitalisation and resulting functional decline. Greater attention to prevention and individualized care are needed to reduce the burden of diabetic foot disease in the elderly.

Plantar pressure distribution in Type 2 diabetic patients without peripheral neuropathy and peripheral vascular disease

AIMS

To evaluate the distribution of plantar pressure during walking on a level gradient in patients with Type 2 diabetes mellitus without any microvascular and macrovascular complications and to compare them with non-diabetic control subjects.

METHODS

A group of 15 patients with Type 2 diabetes mellitus without either peripheral neuropathy or peripheral vascular disease (PVD), as well as without both diabetic retinopathy and nephropathy, was compared with a group of 15 non-diabetic subjects matched for age, sex, body weight and height. The plantar pressure and duration of plantar pressure were measured on big toe, 1st, 3rd and 5th metatarsal heads, and on the heel of both feet by Force Sensing Resistors sensors. The static contact plantar surface was measured by method of Harris footprints.

RESULTS

The diabetic group showed a significant increase in peak plantar pressure at the level of the big toe [right foot 205 +/- 94 vs. 101 +/- 39 kPa (mean +/- SD), P = 0.01; left foot 165 +/- 61 vs. 104 +/- 43 kPa, P = 0.05] and 5th metatarsal head (right foot 160 +/- 68 vs. 97 +/- 32 kPa, P = 0.05; left foot 174 +/- 65 vs. 91 +/- 42 kPa, P = 0.02) with a significantly prolonged duration of plantar pressure at each step. Under the heel, the peak plantar pressure was significantly lower in the diabetic group (right foot 187 +/- 54 vs. 321 +/- 91 kPa, P = 0.05; left foot 184 +/- 63 vs. 298 +/- 110 kPa, P = 0.05). No significant differences were noted under 1st and 3rd metatarsal heads. The contact plantar surface was significantly reduced in the diabetic group compared with control subjects (right foot 118.2 +/- 10.8 vs. 141.5 +/- 12.7 cm2, P = 0.05; left foot 127.5 +/- 8.7 vs. 140.0 +/- 11.1 cm2, P = 0.05).

CONCLUSIONS

We observed an anterior displacement of weight-bearing during walking on a level gradient as well as a reduced static contact plantar surface in diabetic patients without evidence of any complications compared with the non-diabetic control group. This could be a premature sign of peripheral neuropathy, which is not evaluated on clinical examination or quantitative sensory testing used in clinics.

A real-time plantar pressure feedback device for foot unloading

OBJECTIVE

To develop and test a plantar pressure control device that provides both visual and auditory feedback and is suitable for correcting plantar pressure distribution patterns in persons susceptible to neuropathic foot ulceration.

DESIGN

Pilot test.

SETTING

Sports medicine laboratory in a university in France.

PARTICIPANT

One healthy man in his mid thirties.

INTERVENTIONS

Not applicable. Main outcome measures A device was developed based on real-time feedback, incorporating an acoustic alarm and visual signals, adjusted to a specific pressure load. Plantar pressure measured during walking, at 6 sensor locations over 27 steps under 2 different conditions: (1) natural and (2) unloaded in response to device feedback.

RESULTS

The subject was able to modify his gait in response to the auditory and visual signals. He did not compensate for the decrease of peak pressure under the first metarsal by increasing the duration of the load shift under this area. Gait pattern modification centered on a mediolateral load shift.

CONCLUSIONS

The auditory signal provided a warning system alerting the user to potentially harmful plantar pressures. The visual signal warned of the degree of pressure. People who have lost nociceptive perception, as in cases of diabetic neuropathy, may be able to change their walking pattern in response to the feedback provided by this device. The visual may have diagnostic value in determining plantar pressures in such patients. This pilot test indicates that further studies are warranted.

Gait assessment in Parkinson's disease: toward an ambulatory system for long-term monitoring

An ambulatory gait analysis method using body-attached gyroscopes to estimate spatio-temporal parameters of gait has been proposed and validated against a reference system for normal and pathologic gait. Later, ten Parkinson's disease (PD) patients with subthalamic nucleus deep brain stimulation (STN-DBS) implantation participated in gait measurements using our device. They walked one to three times on a 20-m walkway. Patients did the test twice: once STN-DBS was ON and once 180 min after turning it OFF. A group of ten age-matched normal subjects were also measured as controls. For each gait cycle, spatio-temporal parameters such as stride length (SL), stride velocity (SV), stance (ST), double support (DS), and gait cycle time (GC) were calculated. We found that PD patients had significantly different gait parameters comparing to controls. They had 52% less SV, 60% less SL, and 40% longer GC. Also they had significantly longer ST and DS (11% and 59% more, respectively) than controls. STN-DBS significantly improved gait parameters. During the stim ON period, PD patients had 31% faster SV, 26% longer SL, 6% shorter ST, and 26% shorter DS. GC, however, was not significantly different. Some of the gait parameters had high correlation with Unified Parkinson's Disease Rating Scale (UPDRS) subscores including SL with a significant correlation (r = -0.90) with UPDRS gait subscore. We concluded that our method provides a simple yet effective way of ambulatory gait analysis in PD patients with results confirming those obtained from much more complex and expensive methods used in gait labs.

Efficacy of a new pressure-sensitive alarm for clinical use in orthopaedics

The current study evaluated a new pressure alarm and compared the ability of subjects to limit weightbearing to 20 lb with and without the alarm. The 28 subjects were divided into four groups (Group 1, n = 7, mean age, 33 years, with normal sensation; Group 2, n = 7, mean age, 59 years, with normal sensation; Group 3, n = 6, mean age, 56 years, without protective lower limb sensation, and Group 4, n = 8, mean age, 39 years, with transtibial amputation). All subjects were instructed in partial weightbearing ambulation and then practiced weight shifting onto a scale set at 20 lb for 2 minutes. Average peak force was measured using the F-scan in-shoe sensor while subjects ambulated in two trials: one with a deactivated pressure alarm and the other with an activated alarm. Data were analyzed using two-tailed t tests. In Groups 1, 2, and 4, significantly lower average peak force with the activated alarm versus deactivated alarm occurred in 43%, 86%, and 100% of subjects, respectively. Weightbearing was limited to less than 20 lb with the activated alarm in 86%, 57%, 33%, and 38% of subjects versus 71%, 14%, 0%, and 0% of subjects with the deactivated alarm, respectively.

Relationship between peripheral vascular disease and high plantar pressures in diabetic neuro-ischaemic patients

BACKGROUND

It has been shown that high foot pressure in diabetic patients plays a crucial role in plantar ulcer development. The purpose of the study is to analyze the relationship between foot arterial pressures and plantar pressures in diabetic patients with both peripheral neuropathy vascular disease.

METHODS

We have evaluated the relationship between foot arterial pressures and plantar pressure parameters (Peak Plantar Pressure, Foot-Floor Contact and Plantar Pressure Integral) in eleven diabetic patients with both peripheral neuropathy and peripheral vascular disease. Peripheral neuropathy was defined as a tuning fork score<4/8 measured at the great toe and internal malleolus with a Tuning fork (Rydel-Seiffer 128 Hz), the absence of both patellar and ankle reflexes and with a temperature discrimination more than +5 degrees C (Thermocross). The peripheral vascular disease (PVD) was evaluated by Doppler technique. Peak Plantar Pressure (PPP) and Foot-Floor Contact (FFC) were measured by Force-Sensing Resistive (FSR 174) sensors under the 1st, 3rd and 5th metatarsal heads as well as under the heel and big toe of both feet. The Plantar Pressure Integral (PPI) was defined by the integral of the pressure over the time.

RESULTS

We have found significant relationship between plantar pressure parameters (PPP, FFC, and PPI) under the first metatarsal heads and Doppler arterial pressures of both tibial posterior and dorsalis pedis artery. However, there was no relationship between Doppler arterial pressures and plantar pressure parameters (PPP, FFC, PPI) under 3rd and 5th metatarsal heads or under both the heel and the big toe.

CONCLUSION

According to our results, the peripheral vascular disease could contribute to the elevation of plantar pressures and to the prolonged duration of foot floor contact at each step in diabetic patients with both peripheral neuropathy and peripheral vascular disease. In such patients, severe ischaemia could lead to an increased risk of foot ulceration and consecutive lower extremity amputation.

Novel Award 2002. Comparison of physical activity and cumulative plantar tissue stress among subjects with and without diabetes mellitus and a history of recurrent plantar ulcers

OBJECTIVES

To compare the amount of weight-bearing activity and estimates of cumulative plantar tissue stress between subjects with and without diabetes mellitus and a history of recurrent plantar ulcers.

DESIGN

Cross-sectional study with matched groups.

BACKGROUND

Weight-bearing activity among individuals with diabetes is likely to influence the amount of mechanical trauma accumulated by plantar tissues, yet activity levels have not been accounted for in previous measurements of plantar tissue stress or predictions of plantar tissue injury.

METHODS

Study groups included subjects with diabetes mellitus and peripheral neuropathy, either with or without a history of recurrent plantar ulcers, and non-diabetic control subjects (n=10 per group). Pressure on the plantar foot was assessed as subjects walked at their preferred speed in the shoes they reported wearing most often each day. Physical activity was monitored over seven consecutive days using an accelerometer. The product of mean daily strides and forefoot pressure-time integral was used to estimate daily cumulative stress on the plantar forefoot.

RESULTS

Subjects with diabetes and a history of recurrent plantar ulcers were 46% less active than subjects without diabetes (mean (SD)=2727 (1345) versus 5037 (2624) strides/day, P=0.04), and accumulated 41% less daily stress on the forefoot than non-diabetic and diabetic control subjects without a history of plantar ulcers (mean (SD)= 210 (134) versus 354 (118) and 354 (148) MPas/day respectively, P=0.03).

CONCLUSIONS

Subjects with diabetes and a history a previous ulcers may be susceptible to plantar tissue injury even at relatively low levels of cumulative tissue stress.

RELEVANCE

Changes in weight-bearing activity following plantar tissue injury in patients with diabetes may influence plantar tissue adaptation and the risk of ulcer recurrence.

Pedobarographic and musculoskeletal examination of collegiate dancers in relevé

Twenty-one collegiate ballet pupils were evaluated via history/questionnaire, musculoskeletal assessment, and pedobarographs, focusing on factors (e.g., alignment of hip, knee, and foot) thought to affect the important and common second-position relevé in dance. In a blinded manner, three observers classified the pedobarographs (obtained by an independent examiner) according to force distribution through the foot. Most dancers bore weight through the toes and transmitted force on both the medial and central metatarsal heads, and some transmitted force through only one of these rays, but none transmitted force through the lateral ray alone. This analysis provides a baseline for future assessment of normal or abnormal dance maneuvers.

In-shoe multisensory data acquisition system

Patients with diabetes and peripheral neuropathy are susceptible to unnoticed trauma on the foot that can cause skin breakdown. We have designed an electronic system in a shoe that monitors temperature, pressure, and humidity, storing the data in a battery-powered device for later uploading to a host computer for data analysis. The pressure sensors are located at the heel, and under three metatarsal heads. Temperature sensors are located under the medial metatarsal head and under the heel. The humidity sensor is located in the toe of the shoe. Correlations of data from pressure sensors with known values were high (r > 0.85), even after extended use. Although data currently are being collected for descriptive purposes, the design potentially can be used to provide feedback to patients.