Effect of sock on biomechanical responses of foot during walking

BACKGROUND: Except the plantar pressure and gross joint motion, we know little about the mechanical state of a foot during walking. This study aimed at investigating the effect of wearing socks with different frictional properties on plantar shear, which is a possible mechanical risk factor of foot lesion development. METHOD: A 3-D finite element model for simulating the foot-sock-insole contact was developed to investigate the biomechanical effects of wearing socks with different combinations of frictional properties on the plantar foot contact. The dynamic plantar pressure and shear stress during the stance phases of gait were studied through finite element computations. Three cases were simulated, a barefoot with a high frictional coefficient against the insole (0.54) and two socks, one with a high frictional coefficient against the skin (0.54) and a low frictional coefficient against the insole (0.04) and another with an opposite frictional properties assignment. FINDINGS: Wearing sock of low friction against the insole to allow more relative sliding between the plantar foot and footwear was found to reduce the shear force significantly: at the rearfoot from 3.1 to 0.88 N, and at the forefoot from 10.61 to 1.61 N. The shear force can be further reduced to 0.43 N at the rearfoot, and 1.18 N at the forefoot, when wearing the sock with low friction against the foot skin and high friction set against the insole. INTERPRETATION: Wearing sock with low friction against the foot skin was found to be more effective in reducing plantar shear force on the skin than the sock with low friction against the insole. The risk of barefoot walking in developing plantar shear related blisters and ulcers might be reduced by socks wearing especially those with low friction against the foot skin.     

Plantar pressures are elevated in the neuroischemic and the neuropathic diabetic foot

OBJECTIVE: Clinical observation has noted that diabetic neuropathic ulcers occur frequently on the plantar surface, whereas neuroischemic ulcers seem to occur often on the foot margins. The reason for this difference in the site of ulceration is unknown, but it may be related to differences in pressure loading. The aim of the study was to compare vertical in-shoe foot pressures measured during walking (using the F-SCAN system) in four groups of patients whose degree of neuropathy was measured by vibration perception threshold (VPT). RESEARCH DESIGN AND METHODS: Subjects included 14 neuroischemic diabetic patients (VPT 29.3 +/- 13.5 V) with history of ulceration on the margins of the foot, 18 patients with neuropathy alone (VPT 38.7 +/- 12.7 V) and previous history of ulceration on the plantar surface, 10 diabetic control patients (VPT 9.9 +/- 2.7 V), and 15 nondiabetic control subjects (VPT 7.0 +/- 0.5 V). RESULTS: When compared with the other three groups, neuroischemic patients had higher foot pressures when measured as mean peak pressures and highest peak pressures under four areas of the foot: medial and lateral forefoot, hallux, and heel. Furthermore, when measuring the maximum pressures developed at any point under the plantar surface, the neuroischemic patients also had the most elevated pressures (757.6 +/- 135.9 kPa), significantly higher than those found in the neuropathic group (482.8 +/- 68.6 kPa, P = 0.04) and in both diabetic control patients (310.2 +/- 34.7 kPa, P = 0.008) and nondiabetic controls subjects (365.1 +/- 49.8 kPa, P = 0.007). CONCLUSIONS: Despite having increased plantar pressures and a comparable degree of neuropatny, the neuroischemic patients did not have a history of ulceration on the plantar surface. These observations may have relevance to different mechanisms of ulcer formation in the neuroischemic and neuropathic foot.     

Plantar tissue thickness is related to peak plantar pressure in the high-risk diabetic foot.

OBJECTIVE: To investigate the relationship among plantar foot pressure, plantar subcutaneous tissue thickness, severity of neuropathy (vibration perception threshold [VPT]), callus, and BMI in a large group of neuropathic diabetic patients at risk of foot ulceration. RESEARCH DESIGN AND METHODS: A total of 157 diabetic neuropathic patients (VPT >25 V) without either peripheral vascular or ulcer history were studied. Plantar foot pressure and plantar tissue thickness were measured at each metatarsal head (MTH) using an optical pedobarograph and an ultrasound scanning platform, respectively. RESULTS: A significant association was observed between peak plantar pressure and plantar tissue thickness at all MTHs (-0.26 < r < -0.61, P < 0.0001), with the least pronounced association at the first MTH. In addition, the pressure time integral was significantly associated with plantar tissue thickness (-0.24 < r < -0.57, P < 0.0001). BMI was significantly related to plantar tissue thickness (0.18 < r < 0.45, P < 0.05), but not to peak forefoot pressures. Subjects with callus had significantly reduced plantar tissue thickness at all MTHs except the first MTH and increased peak pressures at all MTHs (P < 0.001). CONCLUSIONS: This study confirms a strong inverse relationship between plantar tissue thickness and dynamic foot pressure measurements. Long-term follow-up of this patient population will confirm whether reduced plantar tissue thickness predicts the development of diabetic foot ulcers.     

Use of experimental padded hosiery to reduce abnormal foot pressures in diabetic neuropathy

High pressures under the feet of diabetic patients with neuropathy are associated with the development of plantar ulceration. The aim of management is the reduction of such stresses with orthoses and insoles. An American hosiery manufacturer has developed socks designed to reduce stress on athletes' feet, and we report a preliminary evaluation of this technique in the reduction of elevated plantar pressure in 27 neuropathic diabetic patients. With a computerized optical pedobarograph, three footsteps on each side were recorded under three conditions: 1) barefoot, 2) wearing the patients' own hosiery, and 3) wearing experimental patented padded hosiery. The patients' own hosiery did not have a significant effect on plantar pressure, but the experimental hosiery reduced both peak forefoot pressure and the area under the time-pressure curve (P less than .001) by a mean of 26 and 29%, respectively. We conclude that the experimental hosiery is effective in reducing vertical pressures under the diabetic foot and, in conjunction with established orthotic techniques, may be a useful addition to the treatment of the diabetic patient at risk for foot ulceration.     

The forefoot-to-rearfoot plantar pressure ratio is increased in severe diabetic neuropathy and can predict foot ulceration

OBJECTIVE: We have previously demonstrated that high plantar pressures can predict foot ulceration in diabetic patients. The aim of the present study was to evaluate both the relationship between forefoot and rearfoot plantar pressure in diabetic patients with different degrees of peripheral neuropathy and their role in ulcer development. RESEARCH DESIGN AND METHODS: Diabetic patients of a 30-month prospective study were classified according to the neuropathy disability score: scores of 0, 1-5, 6-16, and 17-28 are defined as absent (n = 20), mild (n = 66), moderate (n = 95), and severe (n = 57) neuropathy, respectively. The F-Scan mat system was used to measure dynamic plantar pressures. The peak pressures under the forefoot and the rearfoot were selectively measured for each foot, and the forefoot-to-rearfoot ratio (F/R ratio) was calculated. RESULTS: Foot ulcers developed in 73 (19%) feet. The peak pressures were increased in the forefoot of the severe and moderate neuropathic groups compared with the mild neuropathic and non-neuropathic groups (6.2 +/- 4.5 and 3.8 +/- 2.7 vs. 3.0 +/- 2.1 and 3.3 +/- 2.1 kg/cm(2) [mean +/- SD], respectively; P < 0.0001). The rearfoot pressures were also higher in the severe and moderate neuropathic groups compared with the mild neuropathic and non-neuropathic groups (3.2 +/- 2.0 and 3.2 +/- 1.9 vs. 2.5 +/- 1.3 and 2.3 +/- 1.0, respectively; P < 0.0001). The F/R ratio was increased only in the severe group compared with the moderate and mild neuropathic and non-neuropathic groups (2.3 +/- 2.4 vs. 1.5 +/- 1.2, 1.3 +/- 0.9, and 1.6 +/- 1.0, respectively; P < 0.0001). In a logistic regression analysis, both forefoot pressure (odds ratio 1.19 [95% CI 1.11-1.28], P < 0.0001) and the F/R ratio (1.37 [1.16-1.61], P < 0.0001) were related to risk of foot ulceration, whereas rearfoot pressure was not. CONCLUSIONS: Both the rearfoot and forefoot pressures are increased in the diabetic neuropathic foot, whereas the F/R ratio is increased only in severe diabetic neuropathy, indicating an imbalance in pressure distribution with increasing degrees of neuropathy. This may lend further evidence toward the concept that equinus develops in the latest stages of peripheral neuropathy and may play an important role in the etiology of diabetic foot ulceration.     

"Pressure gradient" as an indicator of plantar skin injury

OBJECTIVE: Peak plantar pressures (PPPs) have been studied extensively as a contributing factor to skin breakdown, especially in the forefoot where most plantar neuropathic ulcers occur. The purposes of this article were to 1) describe an additional pressure variable, the peak pressure gradient (PPG), 2) determine whether the PPG is higher in the forefoot than in the rearfoot (even when compared with PPP), and 3) determine the correlation between the PPG and PPP at the forefoot and rearfoot in subjects with diabetes, peripheral neuropathy, and a history of plantar ulcer. RESEARCH DESIGN AND METHODS: Twenty subjects (12 male and 8 female) with diabetes, peripheral neuropathy, and a mean +/- SD age of 57 +/- 9 years participated. Plantar pressures were collected during walking in footwear. The PPP and the PPG (defined as the spatial change in plantar pressure across adjacent sites of the foot surface around the PPP) were determined for the forefoot and rearfoot, and the forefoot-to-rearfoot ratios for each variable were calculated. RESULTS: The mean PPG was 143% higher in the forefoot than in the rearfoot, whereas the mean PPP was only 36% higher in the forefoot than in the rearfoot (P < 0.0001). The PPG forefoot-to-rearfoot ratio (2.84 +/- 1.36) was nearly two times greater than the PPP forefoot-to-rearfoot ratio (1.48 +/- 0.58) (P < 0.0001). The correlation between PPP and PPG was r = 0.59 at the forefoot and r = 0.75 at the rearfoot. CONCLUSIONS: The PPG was substantially higher in the forefoot than in the rearfoot even when compared with the PPP. The PPG appears to be providing additional information about the stresses experienced by the soft tissues of the foot, especially in the forefoot. The PPG may be a useful indicator of skin trauma because spatial changes in high plantar pressures may identify high stress concentrations within the soft tissue.     

Reliability and validity of combined imaging and pressures assessment methods for diabetic feet

OBJECTIVES: To determine the reliability of using 3-dimensional (3D) spiral x-ray computed tomography (SXCT) imaging methods to measure anatomic foot structure and to test the validity of using a loading device to simulate walking pressures on the plantar foot during SXCT examination. DESIGN: Nonrandomized control trial of consecutive patients with complete data compared with age-matched controls. SETTING: A clinical SXCT scanner and physical therapy laboratory in a local hospital. PARTICIPANTS: Eight subjects with diabetes and a history of forefoot ulcers and 8 control subjects. INTERVENTIONS: SXCT imaging and plantar pressure analysis were used to acquire 3D volumetric structure and pressure data of the foot during 4 foot positions, 2 weight bearing and 2 non-weight bearing. MAIN OUTCOME MEASURES: Differences between repeated SXCT measures of foot structure. Comparisons of plantar foot pressure. Foot structure measurements. Methods for measuring the bony angles and soft-tissue thickness were developed and reliability tests were performed. RESULTS: There was essentially no bias (<+/-0.5mm or +/-0.5 degrees ) and a high degree of reliability (81% of the measures had a reliability <2.0mm or 2 degrees ) when measuring foot structures. Correlations of pressure measures collected on the loading device compared with those collected during walking were (mean +/- standard deviation) r =.66 +/-.06. The percentage agreement between the pressures collected on the loading device and during walking was 91.1% +/- 4.7%. CONCLUSION: Reliability of anatomic foot structure measurements and validity of plantar loading during visualization were good. These methods may be used to determine structural differences between diabetic and healthy feet and to evaluate how these differences relate to plantar pressures.     

Plantar pressure reduction in step-to gait: a biomechanical investigation and clinical feasibility study

BACKGROUND: Protection of the foot may necessitate reduction of peak pressures in specific plantar regions. The study focuses on the unloading effects that exercising step-to gait may have. METHODS: 20 healthy volunteers were recruited and completed three pedobarographic examinations measuring peak pressures in different gait patterns: normal, half-step length, step-to gait with normal step length on the leading side and zero step length on the trailing side - all gait patterns with an individual but constant cadence. To test clinical feasibility 10 diabetic-neuropathic patients were studied in normal and step-to gait without any restrictions regarding speed or cadence. FINDINGS: Volunteers exercising step-to gait exhibit a significant (P<1%) reduction of peak pressures under the heels and central metatarsals by 9% and 67% on the leading side and of 32% and 19% on the trailing side, respectively. In the diabetic-neuropathic patients unloading effects of the same magnitude but less significant were observed. INTERPRETATION: Reduction of speed reduces peak pressures in all plantar regions. Asymmetry of step patterns reduces peak pressures in the heel and forefoot regions of that foot where heel strike and push-off are suppressed, respectively. However, pressures on the contralateral side are increased. The result is an asymmetric distribution of pressure that is reduced in all regions. Step-to gait may be an option, if pressure protection is required in selected plantar regions. This is confirmed by a feasibility study done with diabetic-neuropathic patients. Protection of the foot, however, is balanced at the cost of harmony of gait, impeding clinical application.     

An exploratory study on differences in cumulative plantar tissue stress between healing and non-healing plantar neuropathic diabetic foot ulcers

BackgroundMechanical stress is important in causing and healing plantar diabetic foot ulcers, but almost always studied as peak pressure only. Measuring cumulative plantar tissue stress combines plantar pressure and ambulatory activity, and better defines the load on ulcers. Our aim was to explore differences in cumulative plantar tissue stress between people with healing and non-healing plantar diabetic foot ulcers.MethodsWe analyzed a subgroup of 31 patients from a randomized clinical trial, treated with a removable offloading device for their plantar diabetic forefoot ulcer. We measured in-device dynamic plantar pressure and daily stride count to calculate cumulative plantar tissue stress at the ulcer location and associated this with ulcer healing and ulcer surface area reduction at four weeks (Student's t and chi-square test for significance, Cohen's d for effect size).FindingsIn 12 weeks, 68% (n = 21) of the ulcers healed and 32% (n = 10) did not. No statistically significant differences were found for cumulative plantar tissue stress, plantar pressure or ambulatory activity between people with healed and not-healed ulcers. Cumulative plantar tissue stress was 25% lower for people with healed ulcers (155 vs. 207 MPa·s/day; P = 0.71; Effect size: d = 0.29). Post-hoc analyses in the 27 patients who self-reported to be adherent to wearing the device showed that cumulative plantar tissue stress was 49% lower for those who reached ≥75% ulcer surface area reduction at four weeks (140 vs. 275 MPa·s/day; P = 0.09; d = 0.76); smaller differences and effect sizes were found for peak pressure (24%), peak pressure-time integral (30%) and ambulatory activity (26%); (P-value range: 0.14–0.97; Cohen's d range: 0.14–0.70).InterpretationMeasuring cumulative plantar tissue stress may provide insight beyond that obtained from plantar pressure or ambulatory activity alone, with regard to diabetic foot ulcer healing using removable offloading devices. These explorative findings provide baseline data for further studies on this relevant topic.     

Lower limb muscle dysfunction may contribute to foot ulceration in diabetic patients

OBJECTIVES: To investigate the relationship between in-shoe plantar foot pressure and the co-ordinated activity of five lower limb muscles of diabetic patients, who are known to have a higher risk of foot morbidity. DESIGN: A portable six channel electromyographic system has been designed, developed and synchronised in real time with a 16 channel piezoelectric transducer in-shoe pressure measuring device, Gaitscan. BACKGROUND: So far, no one has tried to establish a relationship between in-shoe foot pressure distribution and muscle activity of the lower limb in diabetes. The measurement of phasic muscle activity has been related to foot pressure and compared to a control group of normal volunteers. METHODS: Twenty nine diabetic subjects and 22 healthy non-diabetic volunteers have been studied by recording electromyography of lower leg muscles and in-shoe foot pressure measurements simultaneously. RESULTS: In diabetic subjects, the period of contact pressure was greater than in normal control subjects (P<0.003). The initial forefoot time to contact with the ground was shorter in diabetics when compared to controls, indicating a faster forefoot contact. Of the dorsiflexor muscles, the Anterior Tibialis, normally contracting eccentrically at heel strike, was subject to a measurable delay in the initiation of contraction, of mean difference of 180 ms (P<0.001), in diabetic subjects when compared to the normal controls. CONCLUSIONS: The late firing of Tibialis Anterior means that its normal modulating role in lowering the foot to the ground after heel strike through eccentric contraction is disturbed. The result is that the foot reaches the foot flat stage in a less ordered manner, subjecting it to high plantar pressures. RELEVANCE: The results obtained may assist in planning realignment procedures of the foot and help prevent development of ulcers on the sole of the foot in high risk diabetic subjects.     

Relationship of foot deformity to ulcer location in patients with diabetes mellitus

The purpose of this study was to determine whether a relationship existed between type of foot deformity and the location of ulcers in patients with diabetes and insensitive feet. Forty-two ulcerated feet were examined in 40 patients. All patients had severely decreased or absent sensation. Foot deformities were classified according to operational definitions as 1) Charcot's foot, 2) a compensated forefoot varus, or 3) an uncompensated forefoot varus or forefoot valgus. The plantar surface of the midfoot and forefoot was divided into three regions. Six of the 7 patients with a Charcot's foot showed ulceration at the midfoot. Nine of 18 patients with a compensated forefoot varus showed ulceration at the second, third, or fourth metatarsal head. Fifteen of 17 patients with an uncompensated forefoot varus or forefoot valgus showed ulceration at the first or fifth metatarsal. A significant relationship was found between foot deformity and location of ulcer. These results support the hypotheses 1) that insensitivity, coupled with increased, repetitive pressure, is a primary cause of plantar ulcers and 2) that certain foot types are associated with characteristic patterns of pressure distribution and callus formation.     

The efficacy of a removable vacuum-cushioned cast replacement system in reducing plantar forefoot pressures in diabetic patients

Background

The purpose of this study was to determine the plantar forefoot offloading efficacy of a new prefabricated vacuum-cushioned cast replacement system designed for foot ulcer treatment in neuropathic diabetic patients.

Methods

Fifteen diabetic subjects with peripheral neuropathy underwent in-shoe plantar pressure assessment while walking in five different footwear types: a standard vacuum-cushioned system with instantly moldable vacuum cushion and roller outsole, two modified vacuum-cushioned systems, one with flat surface vacuum cushion and one with flat outsole, a forefoot offloading shoe, and a control shoe. Regional peak pressures, pressure–time integrals, and inter-regional load transfers were calculated to determine the mechanical action of the footwear. Perceived walking comfort was tested using a 10-point visual analogue scale.

Findings

Forefoot peak pressures and pressure–time integrals were significantly lower (by 41–56%) in the vacuum-cushioned system compared to control. Compared to the forefoot offloading shoe, the vacuum-cushioned system showed significantly higher metatarsal head peak pressures, similar metatarsal head pressure–time integrals, and significantly lower hallux peak pressures and pressure–time integrals. A major transfer of forefoot load to the midfoot explained the offloading efficacy of the vacuum-cushioned system. Few significant differences were present between the modified and standard vacuum-cushioned systems. Perceived walking comfort was significantly higher in the vacuum-cushioned system (score 6.6) than in the forefoot offloading shoe (score 3.4).

Interpretation

The results showed that the vacuum-cushioned cast replacement system was effective in offloading the plantar forefoot of diabetic patients at risk for ulceration, although the contribution of the instantly moldable vacuum cushion and roller outsole were relatively small. The combined peak pressure, pressure–time integral and walking comfort results indicate that the vacuum-cushioned system may be a useful alternative for the forefoot offloading shoe in offloading the plantar diabetic forefoot.     

The characteristics and clinical significance of plantar pressure distribution in patients with diabetic toe deformity: a dynamic plantar pressure analysis

This study evaluated plantar pressure distribution and its clinical significance in patients with diabetic foot toe deformities. Patients with diabetic claw or hammer toe deformities (patient group; n = 30) and healthy subjects without toe deformities (control group; n = 30) were recruited into the study. Plantar pressures in different regions of the foot were measured using the F-scan(?) in-shoe plantar pressure dynamic analysis system. Peak pressures in the hallux and first to fifth metatarsal heads were significantly higher in the patient group compared with the control group. In the midfoot there was no significant difference between the two groups. Hindfoot peak plantar pressures were significantly lower in the patient group compared with the control group. The results indicated that toe deformities in patients with diabetes increased forefoot plantar pressures to abnormally high levels. If plantar pressure is regularly monitored in patients with diabetic foot, toe deformities might be detected earlier and ulceration prevented.     

Variations in plantar pressure variables across elliptical trainers in older adults

BackgroundEllipticals are used to address walking and cardiorespiratory training goals of older adults, some of whom are at risk for foot injuries. Variations in joint kinematics and muscle demands when using different ellipticals could lead to plantar pressure differences. This study explored plantar pressure variables during gait and use of four ellipticals.MethodsPlantar pressures were recorded while 10 adults [68.1 (4.5) years] walked and used the True, Octane, Life Fitness, and SportsArt ellipticals. Repeated-measures ANOVAs (5 × 1) identified forefoot and heel differences across conditions.FindingsMaximum forefoot forces and peak pressures were significantly lower than walking for each elliptical condition with one exception (Life Fitness peak pressure). However, sustained elliptical pedal contact time contributed to forefoot pressure-time integrals and dosages (i.e., cumulative pressure during one minute of activity) not varying significantly amongst elliptical and walking conditions. Heel maximum forces and peak pressures were significantly lower than walking during all elliptical conditions except SportsArt. Heel contact time on SportsArt and Octane exceeded walking, and SportsArt heel contact time exceeded Life Fitness. Heel pressure-time integral was greater on SportsArt compared to walking, Life Fitness, and True. Sports Art heel dosage exceeded Life Fitness and True.InterpretationWhile elliptical training's sustained double limb support diminished maximal forces and peak pressures under the forefoot and heel compared to walking, each ellipticals' pressure-time integral and dosage were not significantly lower than walking. These findings point to the importance of carefully initiating elliptical training programs to minimize tissue injury, particularly if sensory neuropathy is present.     

膝骨性关节炎患者与正常青年人步态的对照

背景：应用现代步态分析技术研究膝骨性关节炎患者足底压力分布的报道较少,尚未建立骨性关节炎患者特征性的足底压力数据库。目的：比较膝骨性关节炎患者与正常青年人步态特征的差异。方法：运用足底压力测试系统对40例年龄44-70岁膝骨性关节炎患者及10名正常青年人行走时的步态进行测试,观察受试者足底各区域受力时间、单足支撑期参数、步角、足底各分区压力峰值。结果与结论：膝骨性关节炎患者足底各区域受力时间百分比均高于正常青年组,两组足跟内外侧值差异尤为显著：膝骨性关节炎患者足跟触地阶段时问百分比、前足离地阶段时间百分比低于正常青年组,全足支撑阶段时间百分比高于正常青年组;膝骨性关节炎患者足跟侧部区域压力峰值均较正常青年组降低。说明膝骨性关节炎患者步态指标具有特征性,足跟部触地时间百分比、足跟触地阶段时间百分比、全足支撑阶段时间百分比及前足离地阶段时间百分比均与正常人有明显区别,膝骨性关节炎患者足跟部位外侧肌肉活动和平衡能力控制都较正常年轻人弱。     

Effects of Kinesio Taping on postural balance in patients with low back pain,a randomized controlled trial

Purpose: to identify postural balance changes in subjects with low back pain after the application of Kinesio Taping, which is then compared to a no treatment control group, using baropodometric evaluation. Methods: This randomized controlled trial was carried out on 50 individuals (both sexes) with chronic low back pain. They were then randomized into two groups: an experimental group - EG (treated with Kinesio Taping in the lumbar region) and a control group - CG (no intervention). Both groups underwent a baropodometric evaluation (mean plantar pressure, peak plantar pressure, plantar surface, mass distribution on right foot and left foot, mass distribution on forefoot and rear foot and base width) at four different moments: pre-intervention, 10 minutes, 48 hours, and 10 days after the intervention on the EG. The level of statistical significance was established at 5%. Results: Significant changes were observed in the EG compared to the CG. In the EG, peak pressure reduced on both right and left foot after Kinesio Taping application; the right base width was reduced, and the mass distribution between the forefoot and the rear foot normalized towards the ideal 50% distribution. These changes happened 48 hours after the Kinesio Taping application, with effects lasting up to 10 days. Conclusion: The use of Kinesio Taping in the lumbar region of subjects with chronic low back pain improved postural balance. This is proved by changes in peak plantar pressure, plantar surface, and mass distribution 48 h after Kinesio Taping application, with effects lasting up to 10 days.     

Removable cast walker boots yield greater forefoot off-loading than total contact casts

Background

Elevated plantar loading has been implicated in the etiology of plantar ulceration in individuals with diabetes mellitus and peripheral neuropathy. Total contact casts and cast walker boots are common off-loading strategies to facilitate ulcer healing and prevent re-ulceration. The purpose of this study was to compare off-loading capabilities of these strategies with respect to plantar loading during barefoot walking.

Methods

Twenty-three individuals with diabetes, peripheral neuropathy, and plantar ulceration were randomly assigned to total contact cast (n = 11) or removable cast walker boot (n = 12). Each subject underwent plantar loading assessment walking barefoot and wearing the off-loading device. Analysis of covariance was used to compare loading patterns in the off-loading devices for the whole foot, hindfoot, midfoot, and forefoot while accounting for walking speed and barefoot loading.

Findings

For the foot as a whole, there were no differences in off-loading between the two techniques. Subjects wearing cast walker boots had greater reductions in forefoot peak pressure, pressure-time integral, maximum force, and force-time integral with respect to barefoot walking. Healing times were similar between groups, but a greater proportion of ulcers healed in total contact casting compared to cast walker boots.

Interpretation

In subjects with diabetes, peripheral neuropathy, and plantar ulceration, cast walker boots provided greater load reduction in the forefoot, the most frequent site of diabetic ulceration, though a greater proportion of subjects wearing total contact casts experienced ulcer healing. Taken together, the less effective ulcer healing in cast walker boots despite superior forefoot off-loading suggests an important role for patient compliance in ulcer healing.     

Plantar pressures in individuals with normal and pronated feet according to static squat depths

[Purpose] The purpose of the present study was to investigate differences in plantar pressure between individuals with normal and pronated feet according to 3 static squat depths. [Subjects and Methods] Study subjects were 10 young adults with normal and pronated feet. Plantar pressures were measured in the standing position and static squat positions at 45° (semi-squat) and 90° (half-squat) knee flexion using the F-Mat. Subjects’ plantar pressures were analyzed by dividing the foot into 4 areas: forefoot medial, forefoot lateral, midfoot, and heel. [Results] In the half-squat position, the pronated foot group showed a higher foot pressure in the forefoot medial than was seen in the normal group, whereas the normal group exhibited a higher foot pressure in the heel than was seen in the pronated foot group. [Conclusion] An increase in squat depth led to the transfer of plantar pressure to the heel in normal feet and to the forefoot medial in pronated feet.Key words: Plantar pressure, Pronated feet, Squat