Pedobarographic findings in patients with knee osteoarthritis

Differences in ankle and knee muscle architecture and plantar pressure distribution among women with knee osteoarthritis

BACKGROUND

The aim of this study was to compare the plantar pressure distribution and knee and ankle muscle architecture in women with and without knee osteoarthritis (OA).

METHODS

Fifty women with knee OA (mean age = 52.11 ± 4.96 years, mean Body mass index (BMI) = 30.94 ± 4.23 kg/m2) and 50 healthy women as a control group (mean age = 50.93 ± 3.78 years, mean BMI = 29.06 ± 4.82 kg/m2) were included in the study. Ultrasonography was used to evaluate knee and ankle muscles architecture and femoral cartilage thickness. The plantar pressure distribution was evaluated using the Digital Biometry Scanning System and Milleri software (DIASU, Italy). Static foot posture was evaluated using the Foot Posture Index (FPI), and pain severity was assessed using the Visual Analog Scale.

RESULTS

The OA group exhibited lower muscle thickness in Rectus Femoris (RF) (p = 0.003), Vastus Medialis (VM) (p = 0.004), Vastus Lateralis (p = 0.023), and Peroneus Longus (p = 0.002), as well as lower Medial Gastrocnemius pennation angle (p = 0.049) and higher Fat thickness (FT) in RF (p = 0.033) and VM (p = 0.037) compared to the control group. The OA group showed thinner femoral cartilage thickness (p = 0.001) and higher pain severity (p = 0.001) than the control groups. FPI scores were higher (p = 0.001) in OA group compared to the control group. The plantar pressure distribution results indicated an increase in total surface (p = 0.027), total load (p = 0.002), medial load (p = 0.005), and lateral load (p = 0.002) on dominant side in OA group compared to the control group.

CONCLUSIONS

Knee and ankle muscle architecture, knee extensor muscle FT, and plantar pressure distribution in the dominant foot differed in individuals with knee OA compared to the control group.

The distribution of pressure forces of the foot on the ground during gait in patients with hip osteoarthritis

BACKGROUND

Hip osteoarthritis is a major civilizational challenge of the ageing population, usually due to the reduced function of gait. In the light of this fact, gait analysis has become an important issue for the doctor, the physiotherapist and the patient, as it serves as a useful tool in diagnosis, recovery, and rehabilitation. Pedobarography is one of the most modern gait analysis methods.

OBJECTIVE

The aim of this study is to assess the distribution of pressure forces of the foot on the ground during gait in patients with hip osteoarthritis.

METHODS

Dynamic foot tests were performed by means of a two-meter RSscan® International platform, equipped with 16.384 sensors with the scanning frequency level exceeding 500 Hz. Patients were divided into two groups: the research group of N= 60 individuals with hip osteoarthritis, aged 52-84; and the control group of N= 32 individuals without hip osteoarthritis, aged 50-74. Data distribution analysis was performed with the Shapiro-Wilk test, followed by a non-parametric Mann-Whitney U test.

RESULTS

The differences between the mean results of maximal peak values of pressure and force in such areas as the big toe, metatarsal I, III, IV, V, lateral and medial heel are significantly lower in the research group than in the control group. Only in the area of metatarsal II, the mean value of pressure is higher in the research group than in the control group. For all metatarsals, the midfoot and medial heel mean results of the contact area are significantly higher in the research group than in the control group. The differences between mean load rate were also tested. The test revealed statistical significance of metatarsal II and III, and the medial heel while metatarsal II displayed a higher mean value in the research group than in the control group.

CONCLUSION

The distribution of the pressure forces of the foot can indicate imbalances which cause degenerative changes. Therefore, early detection of changes can help in prevention or delay of hip osteoarthritis in conjunction with proper therapy.

Translational evaluation of gait behavior in rodent models of arthritic disorders with the CatWalk device - a narrative review

Arthritic disorders have become one of the main contributors to the global burden of disease. Today, they are one of the leading causes of chronic pain and disability worldwide. Current therapies are incapable of treating pain sufficiently and preventing disease progression. The lack of understanding basic mechanisms underlying the initiation, maintenance and progression of arthritic disorders and related symptoms represent the major obstacle in the search for adequate treatments. For a long time, histological evaluation of joint pathology was the predominant outcome parameter in preclinical arthritis models. Nevertheless, quantification of pain and functional limitations analogs to arthritis related symptoms in humans is essential to enable bench to bedside translation and to evaluate the effectiveness of new treatment strategies. As the experience of pain and functional deficits are often associated with altered gait behavior, in the last decades, automated gait analysis has become a well-established tool for the quantitative evaluation of the sequalae of arthritic disorders in animal models. The purpose of this review is to provide a detailed overview on the current literature on the use of the CatWalk gait analysis system in rodent models of arthritic disorders, e.g., Osteoarthritis, Monoarthritis and Rheumatoid Arthritis. Special focus is put on the assessment and monitoring of pain-related behavior during the course of the disease. The capability of evaluating the effect of distinct treatment strategies and the future potential for the application of the CatWalk in rodent models of arthritic disorders is also addressed in this review. Finally, we discuss important consideration and provide recommendations on the use of the CatWalk in preclinical models of arthritic diseases.

Vertical ground reaction forces, paw pressure distribution, and center of pressure during heelwork in working dogs competing in obedience

Heelwork walking is a command that competitive obedience and working dogs are trained to perform. Unlike other canine sports, the research for competitive obedience sport is limited and no research regarding biomechanical gait adaptions during heelwork walking has been published. The aim of the study was to investigate the changes in vertical ground reaction forces, paw pressure distribution (PPD), and center of pressure (COP) of Belgian Malinois during heelwork walking. Ten healthy Belgian Malinois were included in the study. The dogs walked first without heeling (normal walk) and then while heeling on a pressure platform. The comparison between normal and heelwork walking was performed using mixed-effects models. Post-hoc analyses were performed using Sidak's alpha correction procedure. During heelwork walking, a significant decrease in the vertical impulse and stance phase duration (SPD) and a significant increase in the craniocaudal index and speed of COP was observed in the forelimbs compared to normal walking. At the hindlimbs, a significant increase in vertical impulse and SPD was observed during heelwork walking. Regarding PPD, a significant decrease of vertical impulse was observed at the cranial quadrants of the right forelimb and craniolateral quadrant of the left forelimb during heelwork. The area was significantly decreased at the craniolateral quadrant of the left forelimb and the time for the peak vertical force was prolonged significantly at the caudal quadrants of the right forelimb during heelwork walking. The vertical impulse was significantly increased in all quadrants of the hindlimbs except the craniolateral quadrant of the left hindlimb. The effect of these changes on the musculoskeletal system of working dogs should be investigated in further studies, using electromyography and kinematic analysis.

Comparison of Walking Quality Variables between End-Stage Osteonecrosis of Femoral Head Patients and Healthy Subjects by a Footscan Plantar Pressure System

Background and Objectives: Osteonecrosis of the femoral head (ONFH) is a progressive disease with a complex etiology and unknown pathogenesis. Gait analysis can objectively assess the functional behavior of the foot, thus revealing essential aspects and influencing factors of gait abnormalities. The aim of this study was to evaluate the differences in spatiotemporal parameters, static and dynamic plantar pressure parameters, and symmetry indices between patients with ONFH and healthy subjects. Materials and Methods: The study population consisted of 31 ONFH patients and 31 healthy volunteers. Gait parameters were obtained from the plantar pressure analysis system for both the ONFH and healthy groups. The symmetry index was calculated according to a formula, including spatiotemporal parameters, static and dynamic plantar pressure distribution, percentage of regional impulse, and percentage of the restricted contact area. Results: Compared with healthy controls, patients with ONFH had slower walking speed, shorter step length and stride length, and increased stride time, stance time, and percentage of stance. patients with ONFH had lower plantar static pressure on the affected side and higher contralateral plantar static pressure during stance than controls. During walking, the peak pressures in all regions on the affected side and the peak pressure in the toe 1 and metatarsal 3 regions on the healthy side were lower in ONFH patients than in controls. The percentage of contact area and regional impulse in the heel of both limbs were higher in ONFH patients than in the control group. The symmetry indexes of stride time, stance time, step length, maximum force, impulse and contacted area were significantly increased in ONFH patients compared to controls, with decreased symmetry. Conclusions: Osteonecrosis of the femoral head leads to characteristic changes in plantar pressure distribution. These changes may be interpreted as an attempt by patients with ONFH to reduce the load on the affected limb. Plantar pressure analysis may assist in the diagnosis of ONFH and can provide an objective quantitative indicator for the assessment of subsequent treatment outcomes.

Peak pressure during gait in patients with severe haemophilia: A controlled cross-sectional study

BACKGROUND

Patients with severe haemophilia suffer from bleeding-related joint changes in which the ankle joint is most frequently affected. In the resulting gait changes, the forefoot is involved by reducing the foot pressure. However, it is unclear which changes in foot pressure are present in the individual's foot zones.

RESEARCH QUESTION

The aim of the study was to determine whether compensation mechanisms are present in the foot zones regarding the peak pressure under dynamic conditions and to identify possible underlying mechanisms for gait changes.

METHODS

In a controlled cross-sectional study, a pedobarography was performed during gait with a standardized speed (3 km/h) in patients with haemophilia (PwH;n = 40) and healthy controls (Con;n = 40). Pressure pain thresholds (PPT) were detected, and Haemophilia Joint Health Score (HJHS) was performed to determine the current joint status.

RESULTS

PwH showed a decreased peak pressure in metatarsals II-IV and heel compared to Con. Patients with major-affected ankle joints (determined with the HJHS) showed a decreased single-step length, stride-length and stride-time. Accordingly, the cadence was increased by 10 ± 11 steps/min in PwH compared to Con. Furthermore, PwH showed decreased ankle range of motion (ROM) in HJHS and an altered pain perception due to reduced PPT.

SIGNIFICANCE

PwH showed a changed gait pattern in peak pressure compared to Con. A restricted rolling behavior, which might be caused by movement restrictions and pain sensation, leads to reduced pressure in the center forefoot, resulting in a shorter stride-length. Future therapies should focus on maintaining joint mobility for better rolling behavior and improving ankle joints' stability to achieve a balanced load between the midfoot, heel, and forefoot. The use of insoles adapted to our data, based on group differences between PwH and Con, could be supportive in this case.

Center of Pressure in the Paws of Clinically Sound Dogs in Comparison with Orthopedically Diseased Dogs

Simple Summary

The analysis of the center of pressure is an important tool that allows conclusions to be drawn about the body balance of a patient. This balance can be altered by orthopedic or neurological diseases. To date, there are few data on the center of pressure in the paws of walking dogs. This study aimed to show the compensatory changes in the center of pressure parameters within the paw during stance-phase in the walking dog, with data being collected non-invasively by walking dogs with osteoarthritis and healthy dogs (control group) over a pressure platform. Differences in the center of pressure parameters were found between the affected and non-affected limbs of the diseased dogs, but also in comparison to the corresponding limbs of sound dogs. It was shown that dogs with osteoarthritis show different compensatory changes in the center of pressure parameters depending on whether a front or a hind limb are affected. This can reflect a compensatory redistribution of the body mass as well as compensatory changes of body balance. Based on these observations, a deeper investigation of the center of pressure within the paws of dogs would be of interest and a diagnostic application could become possible in the future.

Abstract

The center of pressure (COP) is recognized as a valuable tool for the assessment of orthopedic and neurologic disorders in humans. Relatively few studies are available in veterinary medicine, particularly concerning the COP in the individual paw. This study assessed the dynamic paw COP parameters during the stance phase of dogs with cox- or cubarthrosis (20 dogs each), as well as of 20 sound dogs. Data were obtained by walking over a pressure platform and analyzed within the diseased groups in comparison to the control group. Both diseased groups showed significant differences between the affected and non-affected limbs, but also in comparison to the reference limbs of sound animals. For coxathrosis, the primary increase was in the medio-lateral COP displacement and the COP area in both hind limbs. For cubarthrosis, the most prominent changes were an increase in the medio-lateral COP displacement in the ipsilateral hind limb and in the cranio-caudal COP displacement in the lame limb. Additionally, the COP area increased in both hind limbs. This can reflect a compensatory redistribution of the body mass as well as compensatory changes of body balance.

A Simple Foot Plantar Pressure Measurement Platform System Using Force-Sensing Resistors

Generally, there are two types of working style, i.e., some people work in sitting conditions, and the remaining work mostly in a standing position. For people working in a standing position, they can spend hours in a day doing their work standing. These people do not realize that it can cause medical issues, especially for the feet, namely biometric problems. In addition, several doctors in Indonesia are already aware of this issue and state that the biometric problems faced by those kinds of people can be predicted from the load distribution on the foot. However, the tool used by the doctors in Indonesia to measure biometric problems is not a digital tool. Therefore it is very difficult to measure and predict the biometric problems quantitatively. This study aims to develop a low-cost static load measuring device using force-sensing resistor (FSR) sensors. The measuring instrument is designed in the form of a pressure plate platform which consist of 30 FSR 402 sensors. The sensors are placed right underneath the display area of the foot, 15 sensors on the soles of the left and right feet. Ten students from the Department of Mechanical Engineering, Diponegoro University (five men and five women) were asked to stand on the platform. Each subject also measured foot length (FL) to estimate shoe size, foot area contact (FAC) for validation between genders, and foot type using the digital footprint tools. From the results of measurements obtained for the left foot in the medial mid foot area, i.e., in sensors 5 and 7, not exposed to the load, on almost all subjects except subject number 3 with a load of 0.196 kg on sensor 7. The highest average load occurs in the heel area i.e., sensor 1 measured 0.713 kg and the smallest average load occurs in the five sensors, with 0 kg. A static load gauge that is designed to be used to measure each leg area for subjects with a shoe size of 40–42 with low price to be held in hospital-orthopedic hospitals and biomechanical research centers.

Comparison of effectiveness of the home exercise program and the home exercise program taught by physiotherapist in knee osteoarthritis

BACKGROUND

Home-based exercise therapy is effective in reducing pain and improving function in adults with osteoarthritis of the knee.

OBJECTIVE

To investigate and compare the effectiveness of the home exercise program and the home exercise program taught by a physiotherapist in knee osteoarthritis.

METHODS

The study was conducted with 80 patients with knee osteoarthritis. The patients were randomized into two groups. The first group was given the home exercise brochure by the orthopedist, while the second group did home exercises under the guidance of the physiotherapist. The goniometer for the range of motion (ROM) of the knee, Myometer for evaluation of the quadriceps and hamstring muscles strength, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Short Form Health Survey (SF-36) were used for evaluation.

RESULTS

Statistically significant improvements were found in the post-treatment ROM, VAS, quadriceps and hamstring muscles strength, WOMAC and SF-36 values in both groups (p< 0.05). When the change values were compared, the evaluation results of group II were better than group I statistically (p< 0.05).

CONCLUSIONS

This study proved that home exercises taught by a physiotherapist were more useful for patients with knee osteoarthritis. When the home exercise program is implemented, a new role is created for a physiotherapist.

The effect of total knee arthroplasty on patients' balance and incidence of falls: a systematic review

PURPOSE

Despite the high incidence of falls in patients with OA, few studies have explored whether falls risk is affected after patients undergo total knee arthroplasty (TKA). Therefore, the aim of this systematic review was to identify the extent of the effects of TKA on balance and incidence of falls by critically reviewing the available literature.

METHODS

A systematic review of published literature sources was conducted up to March 2014. All studies assessing balance and incidence of falls after TKA (without physiotherapeutic intervention) were included. The methodological quality of each study was reviewed using the Critical Appraisal Skill Programme tool.

RESULTS

Thirteen studies were included, comprising of ten cohort studies (Level II) and three studies with Level of evidence III.

CONCLUSIONS

Findings provide evidence that TKA improves significantly single-limb standing balance (~60%) and dynamic balance up to 1-year following surgery (Level of evidence II). Moreover, TKA influences positively fear of falling and incidence of falls by switching 54.2 % of pre-operative fallers to post-operative non-fallers (Level of evidence II-III). It is highlighted that knee extension strength, proprioception and symmetrization of postural strategies have not fully recovered post-TKA and influence balance performance. Clinically, these persistent deficits need to be mitigated by physiotherapy even before TKA takes place.

Effects of a therapeutic exercises program associated with pompage technique on pain, balance and strength in elderly women with knee osteoarthritis

Abstract Introduction: Knee Osteoarthritis (OA) affects mainly elderly, being characterized by arthralgia, stiffness and strength and balance deficits. Scientific evidence suggests beneficial effects of exercise therapy on these changes, but lacks detailed protocols. In addition, there were published studies on effects of therapeutic exercise associated with pompage that were not located. Objective: To investigate the effects of a therapeutic exercise program associated with pompage on pain, balance and muscle strength in elderly women with knee osteoarthritis. Methods: A randomized pilot clinical trial that included 22 women (60 - 80 years) diagnosed with knee OA, randomized and allocated by simple raffle into two groups: intervention and control. Intervention group (strengthening and balance exercises and knee pompage) performed two sessions per week for 12 weeks. The control group received educational lectures, they were evaluated before and after 12 weeks: arthralgia- subscale pain of the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire (WOMAC); postural stability- postural balance protocol by Biodex Balance SD and muscle strength- concentric peak torque of the knee extensor by isokinetic dynamometer. The Independent Student t test was used for intergroup analysis. Results: The intervention group compared with the control showed better results for the outcomes pain, balance and muscle strength after 12 weeks. However, the difference was statistically significant (p < 0.05) for levels of antero-posterior oscillation (DM -0.28, 95% CI -0.54 a -0.02; p = 0.035) and global oscillation (DM -0.36, 95% CI -0.68 a -0.04; p = 0.028). Conclusion: The intervention had a positive effect on postural balance in elderly women with knee osteoarthritis.

"Bedside-to-Bench" Behavioral Outcomes in Animal Models of Pain: Beyond the Evaluation of Reflexes

Despite the myriad promising new targets and candidate analgesics recently identified in preclinical pain studies, little translation to novel pain medications has been generated. The pain phenotype in humans involves complex behavioral alterations, including changes in daily living activities and psychological disturbances. These behavioral changes are not reflected by the outcome measures traditionally used in rodents for preclinical pain testing, which are based on reflexes evoked by sensory stimuli of different types (mechanical, thermal or chemical). These measures do not evaluate the impact of the pain experience on the global behavior or disability of the animals, and therefore only consider a limited aspect of the pain phenotype. The development of relevant new outcomes indicative of pain to increase the validity of animal models of pain has been increasingly pursued over the past few years. The aim has been to translate “bedside-to-bench” outcomes from the human pain phenotype to rodents, in order to complement traditional pain outcomes by providing a closer and more realistic measure of clinical pain in rodents. This review summarizes and discusses the most important nonstandard outcomes for pain assessment in preclinical studies. The advantages and drawbacks of these techniques are considered, and their potential impact on the validation of potential analgesics is evaluated.

Neuroplasticity of sensory and sympathetic nerve fibers in a mouse model of a painful arthritic joint

OBJECTIVE

Many forms of arthritis are accompanied by significant chronic joint pain. This study was undertaken to investigate whether there is significant sprouting of sensory and sympathetic nerve fibers in the painful arthritic knee joint and whether nerve growth factor (NGF) drives this pathologic reorganization.

METHODS

A painful arthritic knee joint was produced by injection of Freund's complete adjuvant (CFA) into the knee joint of young adult mice. CFA-injected mice were then treated systemically with vehicle or anti-NGF antibody. Pain behaviors were assessed, and at 28 days following the initial CFA injection, the knee joints were processed for immunohistochemistry analysis using antibodies against calcitonin gene-related peptide (CGRP; sensory nerve fibers), neurofilament 200 kd (NF200; sensory nerve fibers), growth-associated protein 43 (GAP-43; sprouted nerve fibers), tyrosine hydroxylase (TH; sympathetic nerve fibers), CD31 (endothelial cells), or CD68 (monocyte/macrophages).

RESULTS

In CFA-injected mice, there was a significant increase in the density of CD68+ macrophages, CD31+ blood vessels, and CGRP+, NF200+, GAP-43+, and TH+ nerve fibers in the synovium, as well as a significant increase in joint pain-related behaviors. None of these findings were observed in sham-injected mice. Administration of anti-NGF reduced these pain-related behaviors and the ectopic sprouting of nerve fibers, but had no significant effect on the increase in density of CD31+ blood vessels or CD68+ macrophages.

CONCLUSION

These findings demonstrate that ectopic sprouting of sensory and sympathetic nerve fibers occurs in the painful arthritic joint and may be involved in the generation and maintenance of arthritic pain.

Sensibilidade da Escala de Equilíbrio de Berg em indivíduos com osteoartrite

Este estudo teve objetivo de analisar a sensibilidade e especificidade da Escala de Equilíbrio de Berg (EEB) em detectar o risco de queda em indivíduos com osteoartrite de joelho (OAJ). Verificar a associação entre a capacidade funcional, grau de OAJ, quadro álgico, índice de medo de cair e histórico de queda com o escore da EEB. Participaram 69 indivíduos com OAJ. Foram analisados os pontos de corte 45, 47, 49, 51 e 53 pontos da EEB, quanto à sensibilidade e especificidade do teste. Utilizou-se a escala analógica visual e os questionários WOMAC e Índice de preocupação em cair (FES-I). Os resultados evidenciaram diferença significativa (p=0,001) no escore da EEB entre os indivíduos com OAJ com e sem história de queda. A EEB apresentou correlação com Womac, FES-I, histórico de queda e grau de OAJ. A EEB não apresentou um ponto de corte ideal para indivíduos com OAJ. Contudo, a escala é sensível às diferenças individuais nesta população.

Sensory and sympathetic nerve fibers undergo sprouting and neuroma formation in the painful arthritic joint of geriatric mice

Introduction

Although the prevalence of arthritis dramatically increases with age, the great majority of preclinical studies concerning the mechanisms that drive arthritic joint pain have been performed in young animals. One mechanism hypothesized to contribute to arthritic pain is ectopic nerve sprouting; however, neuroplasticity is generally thought to be greater in young versus old nerves. Here we explore whether sensory and sympathetic nerve fibers can undergo a significant ectopic nerve remodeling in the painful arthritic knee joint of geriatric mice.

Methods

Vehicle (saline) or complete Freund's adjuvant (CFA) was injected into the knee joint of 27- to 29-month-old female mice. Pain behaviors, macrophage infiltration, neovascularization, and the sprouting of sensory and sympathetic nerve fibers were then assessed 28 days later, when significant knee-joint pain was present. Knee joints were processed for immunohistochemistry by using antibodies raised against CD68 (monocytes/macrophages), PECAM (endothelial cells), calcitonin gene-related peptide (CGRP; sensory nerve fibers), neurofilament 200 kDa (NF200; sensory nerve fibers), tyrosine hydroxylase (TH; sympathetic nerve fibers), and growth-associated protein 43 (GAP43; nerve fibers undergoing sprouting).

Results

At 4 weeks after initial injection, CFA-injected mice displayed robust pain-related behaviors (which included flinching, guarding, impaired limb use, and reduced weight bearing), whereas animals injected with vehicle alone displayed no significant pain-related behaviors. Similarly, in the CFA-injected knee joint, but not in the vehicle-injected knee joint, a remarkable increase was noted in the number of CD68⁺ macrophages, density of PECAM⁺ blood vessels, and density and formation of neuroma-like structures by CGRP⁺, NF200⁺, and TH⁺ nerve fibers in the synovium and periosteum.

Conclusions

Sensory and sympathetic nerve fibers that innervate the aged knee joint clearly maintain the capacity for robust nerve sprouting and formation of neuroma-like structures after inflammation/injury. Understanding the factors that drive this neuroplasticity, whether this pathologic reorganization of nerve fibers contributes to chronic joint pain, and how the phenotype of sensory and sympathetic nerves changes with age may provide pharmacologic insight and targets for better controlling aging-related joint pain.

Plantar pressure and foot pain in the last trimester of pregnancy

BACKGROUND

Back and foot pain are common complaints during pregnancy. Progression of symptoms is seen especially in the third trimester as the center of gravity (COP) is altered due to weight gain. The aim of the study was to evaluate plantar pressure changes and postural balance differences of pregnant women.

MATERIAL AND METHODS

Thirty-five last trimester pregnant women with complaints of foot pain were included. The control group consisted of 35 non-pregnant women who were age and body mass index (BMI) matched volunteers. All selected cases were overweight. Foot pain in pregnancy was measured by Visual analogue scale (VAS). Percentages of pressure on forefoot and hindfoot were measured using static pedobarography and peak pressures at forefoot, midfoot and hindfoot were measured using dynamic pedobarography. As a measurement of balance, COP sway length and width were also analyzed.

RESULTS

Compared to overweight individuals, pregnant patients had higher forefoot pressure on the right side with standing and walking. Also, significant increases in contact times under the forefoot and longer floor contact times were found. VAS scores were correlated with forefoot contact times during walking. Although the sway length from COP was higher than controls, no significant correlation was found in sway length and weight gain.

CONCLUSION

These data suggest that forefoot pressures increase in the last trimester of pregnancy during standing and walking. There is prominent increased postural sway in anterior-posterior direction in this period.

CLINICAL RELEVANCE

We believe that based on the observed pressure changes, foot pain in pregnancy due to changes in body mass and distribution may be relieved by exercise and shoewear modifications.

Effects of plantar hardness discrimination training on standing postural balance in the elderly: a randomized controlled trial

Objective: To investigate the effects of sensory perception exercises for discrimination of surface hardness by the soles of the feet on standing postural balance in the elderly.

Design: A randomized two-group parallel controlled trial.

Subjects: Twenty-four healthy people aged from 61 to 71 years were enrolled and randomly assigned to a perception exercise group (n = 12) or a control group (n = 12).

Intervention: The perception exercise group were given a task designed to train ability to discriminate different degrees of hardness of foam rubber. The training period was 10 days. Control group subjects were instructed to maintain a standing posture on foam rubber for 10 seconds for a total of 10 days.

Measurements: Before and after training we measured centre-of-gravity sway with the subject standing, obtaining sway path length and area of ellipse. The Functional Reach Test was used to measure the forward displacement distance of the centre of gravity.

Results: Our data revealed a significant reduction in centre-of-gravity sway post training in the perception exercise group as well as a significant increase in forward displacement of the centre of gravity. These parameters were unchanged in the control group. As to change values (difference between pre- and post-training values), the perception exercise group had significantly better values than the control group, indicating the efficacy of sensory perception exercises.

Conclusions: We demonstrated that standing postural balance was improved by sensory perception exercises involving the soles of the feet. Used in addition to balance training, such training for hardness discrimination could be effective in the clinical setting to improve balance in the elderly.

Techniques for assessing knee joint pain in arthritis

The assessment of pain is of critical importance for mechanistic studies as well as for the validation of drug targets. This review will focus on knee joint pain associated with arthritis. Different animal models have been developed for the study of knee joint arthritis. Behavioral tests in animal models of knee joint arthritis typically measure knee joint pain rather indirectly. In recent years, however, progress has been made in the development of tests that actually evaluate the sensitivity of the knee joint in arthritis models. They include measurements of the knee extension angle struggle threshold, hind limb withdrawal reflex threshold of knee compression force, and vocalizations in response to stimulation of the knee. A discussion of pain assessment in humans with arthritis pain conditions concludes this review.