The effect of changes in foot sensation on plantar pressure and muscle activity.

OBJECTIVE: Purpose was (a) to quantify changes that occur in plantar pressure following attenuation of sensory input from the plantar surface of the foot, and (b) to quantify the resultant changes in motor output as measured by the changes of muscular activation. DESIGN: Cross-sectional design in a laboratory setting. BACKGROUND: The importance of afferent feedback to controlling gait has been demonstrated in quasi-static situations, and with animal models. However, the effects and functional significance of sensory feedback from cutaneous receptors in the plantar surface of the foot during walking are still not resolved. METHODS: Sensory thresholds were determined for the plantar surface of the foot. Sensory feedback was reduced with an ice intervention. Three altered sensory states were tested: whole foot, forefoot and rearfoot ice exposure. Plantar pressure distributions and lower extremity muscle patterns were collected while walking before and after ice exposure. RESULTS: Exposure to ice increased vibration thresholds to low and high frequency vibrations. Peak pressure and pressure-time integral were significantly higher in areas of normal sensitivity and lower at the insensate areas. The center of pressure underfoot shifted away from areas of decreased sensitivity when sensory input is reduced from a portion of the foot. Muscle patterns were significantly altered when sensory feedback was changed. CONCLUSIONS: By altering sensory feedback, one can alter gait kinetics and muscular activation patterns. Cutaneous feedback is important in the regulation and modification of gait patterns, and sensory input needs to be included in any model that attempts to predict motion. RELEVANCE: It is suggested that sensory feedback from the foot is important in the maintenance of normal gait patterns. An understanding of the interaction between the sensory-motor systems may lead to advances in the clinical assessment of subjects with gait disorders. Altering sensory input, by changing shoe, orthotic, and/or surface constructions, may be a method by which abnormal gait patterns can be treated.     

The effects of plantar fasciitis and pain on plantar pressure distribution of recreational runners

Background

Plantar fasciitis is the third most frequent injury in runners. Despite its high prevalence, its pathogenesis remains inconclusive. The literature reports overload as the basic mechanism for its development. However, the way that these plantar loads are distributed on the foot surface of runners with plantar fasciitis and the effects of pain on this mechanical factor has not yet been investigated. Therefore, the aim of this study was to evaluate and compare the plantar pressure distributions during running in runners with symptom or history of plantar fasciitis and runners without the disease.

Methods

Forty-five recreational runners with plantar fasciitis (30 symptomatic and 15 with previous history of the disease) and 60 runners without plantar fasciitis (control group) were evaluated. Pain was assessed by a visual analogue scale. All runners were evaluated by means of the Pedar system insoles during running forty meters at a speed of 12(5%) km/h, using standard sport footwear. Two-way ANOVAS were employed to investigate the main and interaction effects between groups and plantar areas.

Findings

No interaction effects were found for any of the investigated variables: peak pressure (P = 0.61), contact area (P = 0.38), contact time (P = 0.91), and the pressure-time integral (P = 0.50).

Interpretation

These findings indicated that the patterns of plantar pressure distribution were not affected in recreational runners with plantar fasciitis when compared to control runners. Pain also did not interfere with the dynamic patterns of the plantar pressure distributions.     

Pes cavus and pes planus. Analyses and treatment

The arch of the foot serves as an adaptable, supportive base for the entire body. This article discusses how the arch of the foot affects the normal biomechanics of the lower limb. An anatomical overview of the three components of the arch of the foot is presented, identifying the medial longitudinal arch as the arch mainly responsible for related structural problems throughout the lower limb. Deviations in the normal structure of the medial longitudinal arch produce unbalanced, functionally unstable conditions of the foot such as pes cavus or pes planus. Specific evaluation criteria for both pes cavus and pes planus are discussed, in addition to the adverse effects these two disorders have on weight bearing, force dissipation, and normal gait. Compensatory pronation associated with pes planus is one of the most common lower extremity disorders seen currently by physical therapists working in sports medicine, and its causes and related lower limb disorders are discussed. Most of these structural deformities can be corrected through the use of various orthotic devices. Specific guidelines are presented for using both soft and permanent orthoses, which offer the foot increased shock absorption and proper structural alignment.     

The effect of silicone injections in the diabetic foot on peak plantar pressure and plantar tissue thickness: a 2-year follow-up

OBJECTIVE: To report the efficacy of injected liquid silicone (ILS) in the foot at 2 years after administration. DESIGN: Randomized controlled trial. SETTING: Diabetic foot clinic in the United Kingdom. PARTICIPANTS: Twenty-eight diabetic neuropathic patients, randomized into an active treatment group (n=14) and a placebo group (n=14). INTERVENTION: Participants were given either 6 injections of 0.2mL of liquid silicone (silicone group) or equal volumes of saline (placebo group) under metatarsal head sites with callus. MAIN OUTCOME MEASURES: Plantar tissue thickness and plantar pressures were measured at 3, 6, 12, and 24 months postinjection. RESULTS: At 12 months, the plantar tissue thickness in the silicone group had increased by a mean 1.6+/-0.9mm (P=.001), and remained increased at 24 months (1.1+/-0.7mm, P=.003). Peak plantar pressure in the silicone group was reduced at 12 months (-165.0+/-253.5kPa, P=.03), but not at 24 months. There was no change in tissue thickness or peak plantar pressure in the placebo group at 12 and 24 months. The reduction in the pressure time integral (PTI) in the silicone group did not reach significance at 12 months (-.71+/-1.17kPa/s, P=.055). Although PTI returned to baseline at 24 months for the silicone group, it was significantly increased in the placebo group (.64+/-.37kPa/s, P=.043), suggesting that silicone may still exhibit some pressure-reducing properties after 24 months. CONCLUSIONS: The results indicate that at 24 months postinjection the cushioning properties of ILS have reduced, suggesting that booster injections may be required in certain patients.     

Region-specific foot pain and plantar pressure in people with rheumatoid arthritis: A cross-sectional study

BackgroundIt is unclear whether region-specific foot pain may influence plantar pressure in people with established rheumatoid arthritis. The aim was to determine the association between region-specific foot pain and region-specific plantar pressure.MethodsTwenty-one people with rheumatoid arthritis and 19 age- and sex-matched controls participated in this study. Self-reported foot pain in the toes, forefoot, midfoot and rearfoot was assessed using foot diagrams. Peak pressure and pressure time integrals for the toes, forefoot, midfoot and rearfoot were calculated using a pressure mat system. Differences in foot pain and pressure between the groups were calculated using appropriate regression models. To determine associations between region-specific pain and pressure, linear regression models were used while adjusting for body mass and participant group.Findings.Participants with rheumatoid arthritis were primarily elderly female with long disease duration. Compared to controls, participants with rheumatoid arthritis had higher odds of foot pain at the toes (Odds Ratio (OR) = 10.4, P = 0.001), forefoot (OR = 6.3, P = 0.006) and rearfoot (OR = 10.1, P = 0.011). Participants with RA had higher peak pressure at the rearfoot (P = 0.003) and higher pressure time integrals at the forefoot (P = 0.005), midfoot (P = 0.016) and rearfoot (P < 0.001). After adjusting for body mass and participant group, peak pressure was significantly higher at the toes in those with midfoot pain and rearfoot pain.InterpretationPeople with rheumatoid arthritis experience region-wide foot pain and demonstrate differences in pressure distribution compared to people without rheumatoid arthritis. Foot pain at the midfoot and rearfoot is also associated with increases in plantar pressure at the toes.     

Walking casts: effect on plantar foot pressures

Pressure measurements were made at four sites on the right foot of six normal subjects while they walked in a standard shoe, conventional padded cast, total contact cast, and again in a shoe. No differences in mean relative pressure were found between the padded cast and the total-contact cast. Significant reductions in mean relative pressure were found between the standard shoe and walking casts at the first and third metatarsal head. This study supported the use of walking casts in the management of plantar ulcers. The effectiveness of the cast in reducing plantar pressure was not found to be dependent on the cast padding technique.     

Radiographic and plantar pressure assessment of pes planovalgus severity in children with cerebral palsy

BackgroundPes planovalgus is common in children with cerebral palsy. Although severity influences treatment, there still lacks standard clinical measurements to objectively quantify pes planovalgus in this population. The comparison of pedobarographic data and radiographic measurements to clinical evaluation has not been reported in this population.Methods395  feet were identified from a population of ambulatory pediatric patients with cerebral palsy. Each patient initially underwent clinical evaluation by an experienced physical therapist who classified feet as: 136 controls, 116 mild, 100 moderate, and 43 severe pes planovalgus. Quantitative measurements were then calculated from antero-posterior and lateral radiographs of the foot. Pedobarographic analysis included the arch index, center of pressure index, and a newly defined medial index.FindingsA multivariate analysis was performed on the radiographic and pedobarographic measurements collected. It identified seven variables that improved objective classification of pes planovalgus severity when utilized together. These include the foot progression angle, initial contact force, arch index, medial index, antero-posterior talonavicular coverage, lateral calcaneal pitch and lateral Meary's angle. While the lateral calcaneal pitch angle statistically differed amongst all severity classes, no pedobarographic value statistically differed between all severity classes.InterpretationOverall, the combination of radiographic and pedobarographic measurements provides valuable information for objectively classifying severity of pes planovalgus in children with cerebral palsy by utilizing these values together rather than independently. In a clinical setting, radiographs and pedobarographic data may be obtained to enhance assessment of severity and guide treatment.     

足底胼胝体去除术对糖尿病患者足底压力的影响

目的探讨足底胼胝体去除术对减轻糖尿病患者足底压力的效果。方法2008年10月-2009年1月对上海市2个社区筛选出的0级糖尿病足患者39例（72个足）进行足底胼胝体的去除。分别在去除前后使用瑞士产的FootScan足底压力分析仪进行足底压力的测量。结果手术后患者足底总压力、总冲量和局部压力的数值均有所下降（P〈0.05）,但局部冲量下降不明显（P〉0.05）。结论对糖尿病患者足部胼胝体的去除能够降低足底总压力、总冲量及局部压力,对预防糖尿病足的发生和溃疡起到重要的作用。     

Classification of forefoot pain based on plantar pressure measurements

Background

Plantar pressure is widely used to evaluate foot complaints. However, most plantar pressure studies focus on the symptomatic foot with foot deformities. The purposes of this study were to investigate subjects without clear foot deformities and to identify differences in plantar pressure pattern between subjects with and without forefoot pain. The second aim was to discriminate between subjects with and without forefoot pain based on plantar pressure measurements using neural networks.

Methods

In total, 297 subjects without foot deformities of whom almost 50% had forefoot pain walked barefoot over a pressure plate. Foot complaints and subject characteristics were assessed with a questionnaire and a clinical evaluation. Plantar pressure was analyzed using a recently developed method, which produced pressure images of the time integral, peak pressure, mean pressure, time of activation and deactivation, and total contact time per pixel. After pre-processing the pressure images with principal component analysis, a forward selection procedure with neural networks was used to classify forefoot pain.

Findings

The pressure–time integral and mean pressure were significantly larger under the metatarsals II and III for subjects with forefoot pain. A neural network with 14 input parameters correctly classified forefoot pain in 70.4% of the test feet.

Interpretation

The differences in plantar pressure parameters between subjects with and without forefoot pain were small. The reasonable performance of forefoot pain classification by neural networks suggests that forefoot pain is related more to the distribution of the pressure under the foot than to the absolute values of the pressure at fixed locations.     

年龄对正常人步行时足底压力中心轨迹的影响

目的 研究年龄对正常人步行时足底压力中心（COP）轨迹的影响。 方法 选取受试对象（正常人）50例,其中包括青年组25例和老年组25例,采用AL-600型步态与平衡功能训练评估系统对2组受试者进行步态测试,步态监测指标包括足底压力中心总轨迹长(COPD)、各支撑相亚期［首次触地期（LR）、单腿支撑期（SPS）、足蹬离期（PS）］COP在左右方向的平均偏移(COPD-X)及前后方向的平均偏移(COPD-Y),比较2组研究对象步态相关参数间的差异。 结果 青年组和老年组的COPD值分别为（27.88±3.09）cm和（41.03±4.93）cm,老年组COPD较青年组大,差异有统计学意义（P<0.05）。与组内LR亚期同指标比较,2组对象SPS亚期COPD-X和COPD-Y值均较小（P<0.05）。与组内SPS亚期同指标比较,2组对象PS亚期COPD-X和COPD-Y值均较大（P<0.05）。2组对象SPS亚期同指标与组内LR亚期同指标比较,差异无统计学意义（P>0.05）。与青年组同亚期同指标比较,老年组对象LR亚期的COPD-X值、PS亚期的COPD-X和COPD-Y值均增加,差异有统计学意义（P<0.05）。2组对象LR亚期的COPD-Y值、SPS亚期的COPD-X和COPD-Y值比较,差异无统计学意义（P>0.05）。 结论 老年人COPD、COPD-X及COPD-Y较青年人大,跌倒风险增加;步态周期内支撑相各亚期步态参数不同,LR和PS期变异更能显示出步态的稳定性差异。     

Effects of experimentally induced pain of the plantar soles on centre of foot pressure displacements during unperturbed upright stance

Background

Although impaired balance control during quiet standing has repeatedly been reported in persons suffering from foot pain, a better understanding of the effect of foot pain on unperturbed postural control is needed in order to propose and implement efficient podiatry treatments/interventions into clinical practice. The present study was hence designed to address this issue.

Methods

Ten young healthy adults were asked to stand upright, eyes closed, as still as possible in three experimental conditions: (1) a no-pain condition, (2) a condition when a painful stimulation was applied to the plantar surfaces of both feet, and (3) a condition in which painful stimulation was applied to another body part, the palms of both hands. The centre of foot pressure displacements was recorded using a force platform.

Findings

For the same perceived intensity of the pain, the severe painful stimulation applied to the plantar surfaces of both feet increased centre of foot pressure displacements, whereas the severe painful stimulation applied to the palms of both hands did not.

Interpretation

These results reveal the deleterious effect of experimentally induced pain on the plantar soles on unperturbed bipedal postural control. At this point, it is conceivable that these effects of experimental pain could generalise to the effects of pain in patients. Accordingly, the present findings suggest that clinical and/or instrumental interventions designed to mitigate pain in patients suffering from plantar foot pain (e.g., podiatry treatments/interventions) could improve postural control.     

正常足与扁平足的足底压力及步态特征

背景：足底压力测量可揭示人体运动过程中足的动力性特征。目的：测量扁平足患者足底压力参数的分布规律，比较扁平足与正常足的足底压力及步态特征。设计、时间及地点：分组对照的足底生物力学变化检测，于2007—12／2008—01在河北体育学院实验室完成。对象：抽取河北体育学院22～26岁在校学生自愿者，足印足弓空白区宽度与足印最窄区宽度（实心）之比为2：1的正常青年30名，足印无空白区的扁平足青年30名。足底压力分布测试系统Footscaninsole为比利时RSscan公司生产。方法：采用FootscanUSB2平板式足底压测试系统对其进行动态足底压力测试。受试者均脱鞋袜，以个人平常步态自然行走，每人3次，记录动态足底压力。主要观察指标：足底接触面积、着地时相及冲量情况。结果：60名受试者进入结果分析。①足底接触面积：正常足后跟、前掌接触面积的比例均大于扁平足，而足弓接触面积的比例均小于扁平足，差异均具有显著性意义（P〈0．05或0．01）。②着地时相：正常足前掌接触时相、整足接触时相均小于扁平足；而着地时相、离地时相均大于扁平足，差异均具有显著性意义（P〈0．05或0．01）。③冲量：正常足弓、前掌所受冲量占全掌比例均小于扁平足；而后跟所受冲量占全掌比例大于扁平足，差异均具有显著性意义（P〈0．05或0．01）。结论：扁平足前掌接触时相、整足接触时相均大于正常足，着地时间长，压力中心过于密集。扁平足足弓、前掌所受冲量占令掌比例均大于正常足。     

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.     

Painful os peroneum syndrome presenting as lateral plantar foot pain

Lateral plantar foot pain can be caused by various entities, and the painful os peroneum syndrome should be considered in the differential diagnosis. Recent developments in musculoskeletal ultrasonography are very useful for initial diagnosis. We discuss a 69-year-old female who experienced lateral plantar foot pain for over one month. Through physical examination, radiography, ultrasound and magnetic resonance imaging, she was diagnosed with the painful os peroneum syndrome with a chronic fatigue fracture of multipartite os peroneum and peroneus longus tenosynovitis, for which she underwent surgery. We herein report this rare condition and reviewed the relevant literature.     

Relationship between plantar pressure distribution under the foot and insole comfort

In this paper, four pairs of insoles with different comfort characteristics were used to investigate the relationship between the pressure distribution under the foot and running shoe comfort. Fourteen male subjects were tested in four insole conditions by walking and running on a treadmill. The pressure at the plantar surface of the foot was measured by using an EMED pressure-measuring insole. For walking there were significantly higher pressures and forces in the midfoot area and significantly lower pressures in the medial forefoot and hallux area by wearing the most comfortable insole compared with wearing the least comfortable insole. The shift of the pressure from forefoot to midfoot for the most comfortable insole provided an even distribution of the pressure at the plantar surface of the foot. The results also demonstrated that the path of centre of force at the plantar surface of the foot moved to the lateral aspect of the foot for the most comfortable insole. For running, only the pressure in the medial forefoot area was found significantly lower for the most comfortable insole than for the least comfortable insole. The results of this study indicated that the pressure distribution between the plantar surface of the foot and the shoe could detect the change of shoe comfort. Thus it is a suggestion that pressure measurement may be related to understand factors important for shoe comfort.

Comfort of sport shoes is important for the appropriate execution of sport activities. Additionally, comfort may influence fatigue and possibly the development of injuries. The quantification of comfort of sport shoes and the understanding of mechanical and/or biological functions related to it may be enhanced with the use of pressure measurements between the plantar surface of the foot and the shoe sole.     

平地自然行走护士的步态特征和足底压力分布

背景：繁忙的工作和快速行走的严格要求势必造成护士足部压力增高,甚至引起足部疾病。目的：分析护士平地自然行走下的步态特征和足底压力分布。方法：采用比利时RSscan INTERNATIONAL公司生产的足底压力分布测试系统对73名护士进行动态足底压力测试。结果与结论：护士步态分析中足底压强、冲量、支撑时间数据分析一致：在自然步态下,护士足部最大压强部位在第2、3跖骨区;足部最大冲量部位在前足;支撑期时间所占比例最大的是前足离地阶段;加上护士步速较快,足底压力相应增高,前足压力也随其增大。提示护士前足压力较高,易疲劳而发生运动损伤。因此,护士要科学的选择护士鞋或鞋垫,调整足底压力分布和足底冲量,加强对前足、特别是前足第2～3跖骨区的保护,尽可能避免足部疲劳和损伤的发生。     

足底压力测量在步态分析及病理足评估中的应用

学术背景:随着新型传感器技术-压力测量仪器的发展与计算机技术的广泛应用,足底压力测量技术在临床医疗诊断及康复医学中得到越来越广泛的应用,其测量技术也不断的发展成熟,指标也逐步丰富,测量的精度也随之提高。目的:探讨足底压力测量技术在康复医学中的应用研究进展,为康复及临床病理足的生物力学诊疗方法学及相应的参数提供参考依据。检索策略:作者检索了中国全文期刊数据库、Sportdiscuss数据库、http://www.ncbi.nlm.nih.gov/sites/entrez中的1980/2007期间的相关文献。所用中文检索词包括"足底压力、糖尿病足、步态、拇外翻";英文检索词有"plantar pressure,foot pressure,foot stress"。共检索论文360余篇。检索的文献纳入标准:①具有原创性,论点论据可靠的进行实验测试文章。②观点明确,分析全面的文章。③文献主体内容与此课题联系紧密的文章。排除标准:实验设计不合理的文章及观点模糊的综述的相关分析。文献评价:通过对所搜集到的360余篇论文进行分类综述,并将相近和相似种类归为一个种属的方法,从中对230多篇相关论文所出具的观点和测试结果情况进行分析和探讨,确定相关主题、主要研究内容和论文论据。资料综合:通过对大量文献的阅读与分析发现,足底压力测量技术早期的参考文献测量指标单一,数据精度相对低些,近些年来由于计算机技术的飞速发展与各种测量传感器的成功开发与应用,使得足底压力测量精度提高,指标也从最初的压力峰值,逐步增加了压力时间积分、压力中心的飘移速率、足底各区的压力分布等。测量技术的成熟加之康复及临床领域的应用需求使检索到的近几年这方面的文献数量较之过去相对多些,但基本的测量与评价原理变化不大。部分文献的实验测量设计科学严谨,具有较高的实用参考性。结论:关于人体足底压力的各项研究逐步深入,指标由较为单一的垂直力的最大值逐步到压力时间积分、压力中心的飘移速率、足底各区的压力分布等,内容涉及静态足底压力特征、姿势控制、步态分析等,但各项研究的系统性、深入性还不够,尤其是足底压力测量技术各项指标在康复医学中具体应用研究还不完善,在这方面还有很多问题值得研究。随着测量技术的发展,足底压力测量技术必会在康复医学领域得到更为广泛的实际应用。