Consistency of visual assessments of arch height among clinicians

Cross-cultural adaptation and reliability of the Foot Posture Index (FPI-6) - French version

PURPOSE

The 6-item Foot Posture Index (FPI-6) is a reliable tool for the evaluation of foot deformities. Our aim was to translate and cross-culturally validate the FPI-6 for use in French-speaking countries and to determine the intra-rater and inter-rater reliability of the French version.

METHODS

Cross-cultural adaptation was performed according to guidelines. Two clinicians assessed the FPI-6 in 52 asymptomatic individuals. We evaluated intra- and inter-rater reliability with the intraclass correlation coefficients (ICC), correlations (p-value < 0.05) and Bland-Altman plots. Standard error of measurement (SEM) and minimum detectable change (MDC95) were determined.

RESULTS

For the cross-cultural adaptation, we modified several items of the FPI-6 user guide and added footnotes to ensure correct interpretation. ICC of the total FPI-6 scores were 0.94 to 0.96 for the intra- and inter-rater reliability for dominant and non-dominant lower limb. Correlations were significant (p < 0.001); r 0.88 to 0.92. Total score SEM was 0.68 to 0.78 and MDC95 was 1.58 to 1.82.

CONCLUSIONS

Intra- and inter-rater reliability of this French version of the FPI-6 was excellent for the total score and good to excellent for each item. The French FPI-6 can be used in French-speaking countries. The identification of SEM and MDC scores is useful for clinical interpretation.

Joint hypermobility and preschool-age flexible flatfoot

Flexible flatfoot is the most common condition seen in pediatric orthopedic practice and generalized joint hypermobility is widely regarded as one of the predisposing factors. However, in previous studies, the flatfoot was defined by observers' subjective evaluation of the eversion of the bare foot in the standing position; and the joint hypermobility was defined by the Beighton score. The objective of this study is to evaluate the correlation between preschool-age flexible flatfoot and joint hypermobility in preschool-age children objectively. Footprints were measured on a Harris and Beath footprint mat. Flatfoot flexibility was assessed by Staheli Plantar Arch Index (PAI). Other than the Beighton score, 2 new measurement methods, the thumb-to-forearm test and the thumb-thrust test were developed to evaluate joint hypermobility. Of the 291 preschool children from 4 different kindergarten schools included in this study, 156 were boys and 135 were girls. The mean age was 64.18 ± 9.33 months (range 35-88 months). Pearson correlation analysis demonstrated PAI was not associated with the Beighton score (R = 0.020, P = .735), thumb-to-forearm grade (R = 0.109, P = .066), and thumb-thrust grade (R = 0.027, P = .642). Two-sample t-test results showed that the normal and flatfoot groups did not differ significantly in the Beighton score (P = .404), thumb-to-forearm grade (P = .063), and thumb-thrust grade (P = .449). The results demonstrated no correlation between joint hypermobility and preschool-age flexible flatfoot when flatfoot was defined with Staheli PAI and joint hypermobility with the Beighton score. Even with 2 new methods, the thumb-to-forearm test and thumb-thrust test, to define joint hypermobility, we still found no correlation between preschool-age flexible flatfoot and joint hypermobility.

Is there a relationship between lower-extremity injuries and foot postures in professional football players? A prospective cohort study

BACKGROUND

Lower extremity injuries are an ongoing concern for professional football players. This study aims to evaluate the relationship between foot posture and lower extremity injuries in professional football players.

METHOD

In this prospective cohort study, 420 male players of the Iran Premium football league were evaluated during the 2015-2016 season. The players were assessed for their foot types based on optical and static foot scans and foot posture index (FPI). The trained club physicians recorded all injuries during the season.

RESULT

The analyzed data of 244 players showed the highest rate of lower extremity injury in hamstrings, ankle, and groin, respectively. These injuries led to 46% of time loss. The probability of hamstrings injuries was higher among pronated players based on static, optic, FPI, and visual examination, 2.1, 1.8, 1.8, and 2.3, respectively. Medial Collateral Ligament (MCL) injuries were associated with subtalar joint abnormality defined by visual observation. An increased relative risk of leading-to-absence injuries among the flat foot group was significant based on optic scanning, FPI, and visual observation.

CONCLUSION

Abnormal foot postures in professional football players may increase the risk of hamstring and MCL injuries and time loss due to lower extremity injuries.

Flatfeet: Biomechanical implications, assessment and management

Several complications due to flatfeet have been reported in previous literature such as poor postural stability, injuries, pathologies, and discomfort. Early detection and appropriate management are mandatory to minimize these effects. There are different feet assessments established in the field with distinct advantages and disadvantages. Additionally, selection of management methods from various options should be done vigilantly as the application differs according to the individual. Therefore, the objective of this article is to review previous literature on structural anatomy, pathomechanics, assessment, and proper management of flatfeet to provide a condensed summary for healthcare professionals, occupational therapists, kinesiologists, biomechanists, coaches, and ergonomists.

Medial Longitudinal Arch: Accuracy, Reliability, and Correlation Between Navicular Drop Test and Footprint Parameters

OBJECTIVE

The purpose of this study was to evaluate the correlation among the navicular drop test, the arch angle, the Staheli index and the Chippaux-Smirak index. The reliability and the correlation among the footprint parameters were also estimated.

METHODS

A cross-sectional study (n = 86; 59.3% women; 27.8 years, standard deviation: 4.8 years) was carried out. The navicular drop test was evaluated and footprint parameters using a plantar pressure platform were recorded in the dominant foot. Pearson correlation coefficients, intraclass correlation coefficient, standard error of measurement, and minimum detectable change were calculated.

RESULTS

Both intrarater and interrater reliability were excellent for all the parameters evaluated (intraclass correlation coefficients > 0.880). Statistically significant correlations existed between the navicular drop test and footprints parameters (arch angle = 0,643; Staheli index = 0.633; Chippaux-Smirak index = 0.614). The footprint parameters had excellent correlation with each other (0.838-0.881). The navicular drop test and the footprint parameters studied were reproducible and thus had excellent reliability.

CONCLUSION

The correlations obtained between the navicular drop test and the footprint parameters evaluated were good. The navicular drop test appears to be a reproducible, valid, and simple test for evaluating medial longitudinal arch height, having fewer disadvantages than using footprint parameters.

Relationship between the mobility of medial longitudinal arch and postural control

OBJECTIVE

The aim of this study was to analyze the relationship between the medial longitudinal arch mobility and static and dynamic balance.

METHODS

A total of 50 subjects (25 female, and 25 male; Mean age: 22.2 ± 1.3 years; BMI: 22.8 ± 3.8 kg/m²) were included in this study. The relative arch deformity (RAD) was calculated with both 10% and 90% weight bearing (WB). Static balance was evaluated with Single Leg Stance Test and dynamic balance with TechnoBody PK 200WL computerized balance device. Subjects were evaluated for goniometric measurements of lower extremity joints, leg dominance and leg-length discrepancy.

RESULTS

Bipedal dynamic balance was correlated with both feet length at 10% WB and 90% WB. There was a correlation between the dynamic balance on dominant foot and RAD value on the aspect of Medium Speed (r = -0.32, p = 0.02), Perimeter Length (r = -0.32, p = 0.02) and Anterior-Posterior Sway (r = 0.36, p = 0.01). Static balance was unaffected by RAD value when the visual system was eliminated.

CONCLUSION

Our results suggest that decrease of arch mobility on the dominant foot is associated with posterior sway by causing knee or hip strategy and preventing ankle strategy even in small perturbations. The rate of deviation from the equilibrium point and the degree of total swaying increase when arch mobility decreases.

An investigation into the aetiology of flexible flat feet: the role of subtalar joint morphology

AIMS

There is increasing evidence that flexible flatfoot (FF) can lead to symptoms and impairment in health-related quality of life. As such we undertook an observational study investigating the aetiology of this condition, to help inform management. The hypothesis was that as well as increased body mass index (BMI) and increased flexibility of the lower limb, an absent anterior subtalar articulation would be associated with a flatter foot posture.

PATIENTS AND METHODS

A total of 84 children aged between eight and 15 years old were prospectively recruited. The BMI for each child was calculated, flexibility was assessed using the lower limb assessment scale (LLAS) and foot posture was quantified using the arch height index (AHI). Each child underwent a sagittal T1-weighted MRI scan of at least one foot.

RESULTS

An absent anterior subtalar articulation (p < 0.001) and increased LLAS (p = 0.001) predicted a low AHI. BMI was not a significant predictive factor (p = 0.566).

CONCLUSION

This is the first study to demonstrate the importance of the morphology of the subtalar joint on the underlying foot posture in vivo.

TAKE HOME MESSAGE

Flexibility of the lower limb and absence of the anterior facet of the subtalar joint are associated with flexible FF and may influence management of this common condition.

Standard growth of the foot arch in childhood and adolescence--derived from the measurement results of 10,155 children

BACKGROUND

The definition of flatfoot remains analytically vague. Toward the purpose of establishing the standard values of the foot length and arch height in childhood and adolescence, large-scale measurement and investigation of the foot arch were conducted using a three-dimensional foot-measuring device.

METHODS

Measurements of foot structure were performed on 5311 boys and 4844 girls, for a total of 20,310 ft. of 10,155 children aged from 6 to 18 years during the 2006-2008 year period. The foot length (FL) and the navicular height (NH) were measured, and the arch height ratio (AHR (%)=NH×100/FL) was calculated.

RESULTS

The FL in boys showed an extension from the age of 6 to 14 and nearly reached a plateau at 14 years old. In girls, the extension was observed from the age of 6 to 13, and the FL came to a plateau at 13 years old. The NH in boys increased from the age of 6 to 13. In girls, the NH increased from the age of 8 to 13. The AHR, presented a normal distribution, and no differences were observed in the distribution for all ages in boys and girls. In boys, the AHR was almost flat until 11 years old, but elevated in the 11-13 year age period. In girls, the AHR was almost flat until 10 years old, but elevated in the 10-12 year age period.

CONCLUSIONS

We are certain that the data demonstrating the normal growth of the foot contribute to the diagnosis and treatment of the failure of the foot to thrive.

Flexible flatfoot

While being one of the most frequent parental complained deformities, flatfoot does not have a universally accepted description. The reasons of flexible flatfoot are still on debate, but they must be differentiated from rigid flatfoot which occurs secondary to other pathologies. These children are commonly brought up to a physician without any complaint. It should be kept in mind that the etiology may vary from general soft tissue laxities to intrinsic foot pathologies. Every flexible flatfoot does not require radiological examination or treatment if there is no complaint. Otherwise further investigation and conservative or surgical treatment may necessitate.

Custom-molded foot-orthosis intervention and multisegment medial foot kinematics during walking

CONTEXT

Foot-orthosis (FO) intervention to prevent and treat numerous lower extremity injuries is widely accepted clinically. However, the results of quantitative gait analyses have been equivocal. The foot models used, participants receiving intervention, and orthoses used might contribute to the variability.

OBJECTIVE

To investigate the effect of a custom-molded FO intervention on multisegment medial foot kinematics during walking in participants with low-mobile foot posture.

DESIGN

Crossover study.

SETTING

University biomechanics and ergonomics laboratory.

PATIENTS OR OTHER PARTICIPANTS

Sixteen participants with low-mobile foot posture (7 men, 9 women) were assigned randomly to 1 of 2 FO groups.

INTERVENTION(S)

After a 2-week period to break in the FOs, individuals participated in a gait analysis that consisted of 5 successful walking trials (1.3 to 1.4 m/s) during no-FO and FO conditions.

MAIN OUTCOME MEASURE(S)

Three-dimensional displacements during 4 subphases of stance (loading response, midstance, terminal stance, preswing) were computed for each multisegment foot model articulation.

RESULTS

Repeated-measures analyses of variance (ANOVAs) revealed that rearfoot complex dorsiflexion displacement during midstance was greater in the FO than the no-FO condition (F(1,14) = 5.24, P = .04, partial η(2) = 0.27). Terminal stance repeated-measures ANOVA results revealed insert-by-insert condition interactions for the first metatarsophalangeal joint complex (F(1,14) = 7.87, P = .01, partial η(2) = 0.36). However, additional follow-up analysis did not reveal differences between the no-FO and FO conditions for the balanced traditional orthosis (F(1,14) = 4.32, P = .08, partial η(2) = 0.38) or full-contact orthosis (F(1,14) = 4.10, P = .08, partial η(2) = 0.37).

CONCLUSIONS

Greater rearfoot complex dorsiflexion during midstance associated with FO intervention may represent improved foot kinematics in people with low-mobile foot postures. Furthermore, FO intervention might partially correct dysfunctional kinematic patterns associated with low-mobile foot postures.

Posterior tibial tendon dysfunction and flatfoot: analysis with simulated walking

Many biomechanical studies investigated pathology of flatfoot and effects of operations on flatfoot. The majority of cadaveric studies are limited to the quasistatic response to static joint loads. This study examined the unconstrained joint motion of the foot and ankle during stance phase utilizing a dynamic foot-ankle simulator in simulated stage 2 posterior tibial tendon dysfunction (PTTD). Muscle forces were applied on the extrinsic tendons of the foot using six servo-pneumatic cylinders to simulate their action. Vertical and fore-aft shear forces were applied and tibial advancement was performed with the servomotors. Three-dimensional movements of multiple bones of the foot were monitored with a magnetic tracking system. Twenty-two fresh-frozen lower extremities were studied in the intact condition, then following sectioning peritalar constraints to create a flatfoot and unloading the posterior tibial muscle force. Kinematics in the intact condition were consistent with gait analysis data for normals. There were altered kinematics in the flatfoot condition, particularly in coronal and transverse planes. Calcaneal eversion relative to the tibia averaged 11.1±2.8° compared to 5.8±2.3° in the normal condition. Calcaneal-tibial external rotation was significantly increased in flatfeet from mean of 2.3±1.7° to 8.1±4.0°. There were also significant changes in metatarsal-tibial eversion and external rotation in the flatfoot condition. The simulated PTTD with flatfoot was consistent with previous data obtained in patients with PTTD. The use of a flatfoot model will enable more detailed study on the flatfoot condition and/or effect of surgical treatment.

Runner's knowledge of their foot type: do they really know?

BACKGROUND

The use of correct individually selected running shoes may reduce the incidence of running injuries. However, the runner needs to be aware of their foot anatomy to ensure the "correct" footwear is chosen.

OBJECTIVES

The purpose of this study was to compare the individual runner's knowledge of their arch type to the arch index derived from a static footprint.

METHODS

We examined 92 recreational runners with a mean age of 35.4±11.4 (12-63) years. A questionnaire was used to investigate the knowledge of the runners about arch height and overpronation. A clinical examination was undertaken using defined criteria and the arch index was analysed using weight-bearing footprints.

RESULTS

Forty-five runners (49%) identified their foot arch correctly. Eighteen of the 41 flat-arched runners (44%) identified their arch correctly. Twenty-four of the 48 normal-arched athletes (50%) identified their arch correctly. Three subjects with a high arch identified their arch correctly. Thirty-eight runners assessed themselves as overpronators; only four (11%) of these athletes were positively identified. Of the 34 athletes who did not categorize themselves as overpronators, four runners (12%) had clinical overpronation.

CONCLUSION

The findings of this research suggest that runners possess poor knowledge of both their foot arch and dynamic pronation.

Epidemiologic factors affecting plantar arch development in children with flat feet

BACKGROUND

Foot problems are reported by approximately 70% to 80% of adults and 30% of children. One of the most important characteristics affecting its incidence is medial longitudinal arch. Assessing arch height provides valuable information for prescribing appropriate footwear that reduces the consequences of flatfoot. The main goals of this study were to explore epidemiologic factors that affect arch height and to predict arch height in children with flatfoot based on five variables using widely accessible, low-cost tools.

METHODS

This study examined plantar arch height in 80 children with flatfoot aged 7 to 15 years. The evaluation criteria included low arch height, correct knee and heel position, and correct body symmetry. To measure arch height, the children sat in a chair and placed their feet on level ground. A caliper was used to measure the height between the bottom of the navicular tuberosity and the floor. Using least mean square error scheme, a multivariable model was fitted to the plantar arch height for all of the participants using independent variables, including age, Cole index, sex, place of residence, and physical activity.

RESULTS

Arch height increased as age increased in boys and girls in rural and urban areas. A significant increase in arch height occurred in 12- to 15-year-old boys and 10- to 15-year-old girls. In boys, arch height was 30% lower than in girls (P = .05). In children in cities, arch height was lower by 26% than in children in rural areas (P = .05). Arch height increased by 41.8% in inactive boys and by 115.2% in inactive girls in rural areas. It was reduced by 59.4% in boys and by 47.4% in girls as the Cole index increased from 82.2 to 152.0. The suggested model predicted arch height using the child's age, Cole index, sex, place of residence, and physical activity (r > 0.97, error < 0.04 mm [2%], P < .05).

CONCLUSIONS

Flat feet in children may be affected by age, sex, Cole index, place of residence, and physical activity. The proposed model allows plantar arch heights in children with flat feet to be predicted without the need for sophisticated technology via controlling the child's weight and physical activity for prescribing appropriate footwear.

Visual categorisation of the arch index: a simplified measure of foot posture in older people

BACKGROUND

Foot posture is considered to be an important component of musculoskeletal assessment in clinical practice and research. However, many measurement approaches are not suitable for routine use as they are time-consuming or require specialised equipment and/or clinical expertise. The objective of this study was therefore to develop and evaluate a simple visual tool for foot posture assessment based on the Arch Index (AI) that could be used in clinical and research settings.

METHODS

Fully weightbearing footprints from 602 people aged 62 to 96 years were obtained using a carbon paper imprint material, and cut-off AI scores dividing participants into three categories (high, normal and low) were determined using the central limit theorem (i.e. normal = +/- 1 standard deviation from the mean). A visual tool was then created using representative examples for the boundaries of each category. Two examiners were then asked to use the tool to independently grade the footprints of 60 participants (20 for each of the three categories, randomly presented), and then repeat the process two weeks later. Inter- and intra-tester reliability was determined using Spearman's rho, percentage agreement and weighted kappa statistics. The validity of the examiner's assessments was evaluated by comparing their categorisations to the actual AI score using Spearman's rho and analysis of variance (ANOVA), and to the actual AI category using percentage agreement, Spearman's rho and weighted kappa.

RESULTS

Inter- and intra-tester reliability of the examiners was almost perfect (percentage agreement = 93 to 97%; Spearman's rho = 0.91 to 0.95, and weighted kappas = 0.85 to 0.93). Examiner's scores were strongly correlated with actual AI values (Spearman's rho = 0.91 to 0.94 and significant differences between all categories with ANOVA; p < 0.001) and AI categories (percentage agreement = 95 to 98%; Spearman's rho = 0.89 to 0.94, and weighted kappas = 0.87 to 0.94). There was a slight tendency for examiners to categorise participants as having higher arches than their AI scores indicated.

CONCLUSIONS

Foot posture can be quickly and reliably categorised as high, normal or low in older people using a simplified visual categorisation tool based on the AI.

Classification of the height and flexibility of the medial longitudinal arch of the foot

BACKGROUND

The risk of developing injuries during standing work may vary between persons with different foot types. High arched and low arched feet, as well as rigid and flexible feet, are considered to have different injury profiles, while those with normal arches may sustain fewer injuries. However, the cut-off values for maximum values (subtalar position during weight-bearing) and range of motion (ROM) values (difference between subtalar neutral and subtalar resting position in a weight-bearing condition) for the medial longitudinal arch (MLA) are largely unknown. The purpose of this study was to identify cut-off values for maximum values and ROM of the MLA of the foot during static tests and to identify factors influencing foot posture.

METHODS

The participants consisted of 254 volunteers from Central and Northern Denmark (198 m/56 f; age 39.0 ± 11.7 years; BMI 27.3 ± 4.7 kg/m2). Navicular height (NH), longitudinal arch angle (LAA) and Feiss line (FL) were measured for either the left or the right foot in a subtalar neutral position and subtalar resting position. Maximum values and ROM were calculated for each test. The 95% and 68% prediction intervals were used as cut-off limits. Multiple regression analysis was used to detect influencing factors on foot posture.

RESULTS

The 68% cut-off values for maximum MLA values and MLA ROM for NH were 3.6 to 5.5 cm and 0.6 to 1.8 cm, respectively, without taking into account the influence of other variables. Normal maximum LAA values were between 131 and 152° and normal LAA ROM was between -1 and 13°. Normal maximum FL values were between -2.6 and -1.2 cm and normal FL ROM was between -0.1 and 0.9 cm. Results from the multivariate linear regression revealed an association between foot size with FL, LAA, and navicular drop.

CONCLUSIONS

The cut-off values presented in this study can be used to categorize people performing standing work into groups of different foot arch types. The results of this study are important for investigating a possible link between arch height and arch movement and the development of injuries.

A digital photographic measurement method for quantifying foot posture: validity, reliability, and descriptive data

CONTEXT

Although abnormal foot posture long has been associated with lower extremity injury risk, the evidence is equivocal. Poor intertester reliability of traditional foot measures might contribute to the inconsistency.

OBJECTIVES

To investigate the validity and reliability of a digital photographic measurement method (DPMM) technology, the reliability of DPMM-quantified foot measures, and the concurrent validity of the DPMM with clinical-measurement methods (CMMs) and to report descriptive data for DPMM measures with moderate to high intratester and intertester reliability.

DESIGN

Descriptive laboratory study.

SETTING

Biomechanics research laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 159 people participated in 3 groups. Twenty-eight people (11 men, 17 women; age  =  25 ± 5 years, height  =  1.71 ± 0.10 m, mass  =  77.6 ± 17.3 kg) were recruited for investigation of intratester and intertester reliability of the DPMM technology; 20 (10 men, 10 women; age  =  24 ± 2 years, height  =  1.71 ± 0.09 m, mass  =  76 ± 16 kg) for investigation of DPMM and CMM reliability and concurrent validity; and 111 (42 men, 69 women; age  =  22.8 ± 4.7 years, height  =  168.5 ± 10.4 cm, mass  =  69.8 ± 13.3 kg) for development of a descriptive data set of the DPMM foot measurements with moderate to high intratester and intertester reliabilities.

INTERVENTION(S)

The dimensions of 10 model rectangles and the 28 participants' feet were measured, and DPMM foot posture was measured in the 111 participants. Two clinicians assessed the DPMM and CMM foot measures of the 20 participants.

MAIN OUTCOME MEASURE(S)

Validity and reliability were evaluated using mean absolute and percentage errors and intraclass correlation coefficients. Descriptive data were computed from the DPMM foot posture measures.

RESULTS

The DPMM technology intratester and intertester reliability intraclass correlation coefficients were 1.0 for each tester and variable. Mean absolute errors were equal to or less than 0.2 mm for the bottom and right-side variables and 0.1° for the calculated angle variable. Mean percentage errors between the DPMM and criterion reference values were equal to or less than 0.4%. Intratester and intertester reliabilities of DPMM-computed structural measures of arch and navicular indices were moderate to high (>0.78), and concurrent validity was moderate to strong.

CONCLUSIONS

The DPMM is a valid and reliable clinical and research tool for quantifying foot structure. The DPMM and the descriptive data might be used to define groups in future studies in which the relationship between foot posture and function or injury risk is investigated.

Validity of plantar surface visual assessment as an estimate of foot arch height

PURPOSE

Popular running magazines and running shoe companies advise using the shape of the weight-bearing plantar surface of the foot as a basis for selecting a proper type of running shoe to reduce injury risk. The imprint is assumed to reflect the height of the medial longitudinal arch (MLA). This study examined the assumption that plantar surface morphology was a surrogate for height of the MLA.

METHODS

Recruits (n = 3968) entering US Army Basic Combat Training had their plantar foot surfaces assessed visually as low, normal, or high by two raters who viewed imprints of the plantar foot surface. Actual arch height was measured with calipers as distance from the standing surface to the inferior medial border of the navicular tuberosity. Measured MLA heights were compared with plantar surface imprints to evaluate the effectiveness of visual inspection as a means of arch height classification.

RESULTS

For the right foot, individuals with low, normal, or high plantar shapes had a mean +/- SD arch height of 33.5 +/- 6.8, 40.4 +/- 7.2, and 43.1 +/- 7.3 mm, respectively (ANOVA, P < 0.01); however, the individuals' measured MLA heights fell into the corresponding plantar shape percentiles (low, normal, high) only 65% of the time. Increased body mass index (BMI) decreased correct assessment of the MLA.

CONCLUSIONS

Visual assessment of indicating progressively higher plantar shapes corresponded to progressively higher average differences in measured arch heights; nonetheless, there was considerable overlap among the three plantar shapes with 35% of plantar shapes being misclassified compared with measured arch height, especially among individuals with higher BMI.

The effect of low-mobile foot posture on multi-segment medial foot model gait kinematics

A number of in vitro, invasive in vivo, and non-invasive marker based multi-segment foot models (MSFMs) have reported significant motion in the articulations distal to the calcaneus during gait. Few studies, however, have applied a MSFM to the investigation of the effect of foot posture on gait kinematics. Differences in stance phase kinematics between participants with low-mobile (LMF) (n=11) versus "typical" (TYPF) (n=11) foot postures were investigated using a multi-segment medial foot model. Three-dimensional position and stance phase excursions of four functional articulations (rearfoot complex [RC], calcaneonavicular complex [CNC], medial forefoot, first metatarsophalangeal complex) were quantified using an eight optical camera motion analysis system (Vicon Motus, Vicon Motions Systems, Centennial, CO) and a custom written software program (Matlab 7.0.1, The MathWorks, Natick, MA), respectively. Excursions during four subphases of stance phase (loading response, midstance, terminal stance, pre-swing) at each of the functional articulations were compared using multivariate analyses of variance (alpha<or=0.05). Results revealed significantly decreased LMF group CNC abduction excursion (p=0.047) during midstance. During pre-swing, LMF group RC inversion excursion was significantly increased (p=0.032) and eversion excursion was significantly decreased (p=0.003) compared to the TYPF group. When these differences are considered in conjunction with the kinematic patterns of other foot/leg segments and functional articulations, the changes may suggest dysfunction of normal leg-calcaneus coupling and the constrained tarsal mechanism associated with low-mobile foot postures.

Correlation of Harris mats, physical exam, pictures, and radiographic measurements in adult flatfoot deformity

INTRODUCTION

In many reports describing flatfoot deformities, the abnormality is described using observations from physical examination, radiographs, or foot imprints. Correlation of these measurements is often lacking, making determination of the magnitude of the deformity or its surgical correction difficult to quantify.

MATERIAL AND METHODS

Weightbearing AP and lateral radiographs were obtained on 25 patients (39 feet) with a clinically apparent flatfoot deformity and an asymptomatic control group of 28 subjects (56 feet). Radiographs were examined for the lateral talometatarsal angle, the lateral talocalcaneal angle, calcaneal pitch, first metatarsocuneiform height, medial cuneiform -fifth metatarsal height, metatarsus primus elevatus, plantar gapping at the first metatarsocuneiform joint, the AP talonavicular coverage angle, and the metatarsus adductus angle. Harris mat imprints were obtained on each foot and measured for the magnitude of the flatfoot deformity. Physical examination included the subjective appearance to the examiner of the degree of pes planus (none, mild, moderate, severe), hindfoot valgus, and ankle range of motion. Photographs of the hindfoot were obtained in a standardized manner, and hindfoot valgus was measured from these photos and compared to the measured hindfoot valgus on the physical exam.

RESULTS

Statistically significant differences between the two groups were found in the lateral talometatarsal angle, lateral talocalcaneal angle, calcaneal pitch, first metatarsocuneiform height, the AP talonavicular coverage angle, Harris mat imprint score, subjective pes planus score, hindfoot valgus measurement from both photographs and physical examination, ankle range of motion (all with a p value less than 0.01), and the metatarsus adductus angle (p = 0.019). No patient in the control group and 14 (36%) in the flatfoot group had evidence of plantar gapping at the first metatarsocuneiform joint. In the flatfoot group, statistically significant correlations were demonstrated between the Harris mat score and heel valgus as measured by photographic and physical examination, subjective pes planus grading by physical exam, the lateral talometatarsal angle, and the first metatarsocuneiform height.

CONCLUSION

This study validates the use of the Harris mat imprint as an effective method of quantifying the magnitude of a flatfoot deformity. We also found a statistically significant decrease in ankle range of motion in the flatfoot group, indicating that tightness of the gastrocsoleus complex is part of the pathophysiology of flatfoot deformity.

Normative values for the Foot Posture Index

Background

The Foot Posture Index (FPI) is a validated method for quantifying standing foot posture, and is being used in a variety of clinical settings. There have however, been no normative data available to date for comparison and reference. This study aimed to establish normative FPI reference values.

Methods

Studies reporting FPI data were identified by searching online databases. Nine authors contributed anonymised versions of their original datasets comprising 1648 individual observations. The datasets included information relating to centre, age, gender, pathology (if relevant), FPI scores and body mass index (BMI) where available. FPI total scores were transformed to interval logit scores as per the Rasch model and normal ranges were defined. Comparisons between groups employed t-tests or ANOVA models as appropriate and data were explored descriptively and graphically.

Results

The main analysis based on a normal healthy population (n = 619) confirmed that a slightly pronated foot posture is the normal position at rest (mean back transformed FPI raw score = +4). A 'U' shaped relationship existed for age, with minors and older adults exhibiting significantly higher FPI scores than the general adult population (F = 51.07, p < 0.001). There was no difference between the FPI scores of males and females (2.3 versus 2.5; t = -1.44, p = 0.149). No relationship was found between the FPI and BMI. Systematic differences from the adult normals were confirmed in patients with neurogenic and idiopathic cavus (F = 216.981, p < 0.001), indicating some sensitivity of the instrument to detect a posturally pathological population.

Conclusion

A set of population norms for children, adults and older people have been derived from a large sample. Foot posture is related to age and the presence of pathology, but not influenced by gender or BMI. The normative values identified may assist in classifying foot type for the purpose of research and clinical decision making.

Reliability and normative values of the foot line test: a technique to assess foot posture

STUDY DESIGN

Test-retest reliability.

OBJECTIVE

To examine the reliability and report normative values of a novel test, the foot line test (FLT), to describe foot morphology.

BACKGROUND

Numerous foot examinations are performed each day, but most existing examination techniques have considerable limitations regarding reliability and validity.

METHODS

One hundred thirty subjects with mean foot size 44 (41-50 European size) participated. Two examiners, blinded to each other's measurements, measured the right foot of the subjects twice and the left foot once. The position of the most medial aspect of the navicular in the mediolateral direction was projected vertically onto a piece of paper placed under the subject's foot, and compared to the position of the forefoot and hindfoot to obtain the FLT value.

RESULTS

FLT values ranged from -8 to 14 mm, with a mean (+/-SD) of 3.7 +/- 3.4 mm. The intratester reproducibility reported by SEM was 0.8 mm for tester 1 and 0.9 mm for tester 2, while intertester SEM was 1.4 mm for the right foot and 1.3 mm for the left foot. The intrarater ICC was 0.95 for tester 1 and 0.94 for tester 2, while the interrater ICC was 0.86 (left foot) and 0.83 (right foot). There was no significant association between foot size and FLT values.

CONCLUSION

The FLT is a reproducible technique to assess foot posture.

A single-blind pilot study to determine risk and association between navicular drop, calcaneal eversion, and low back pain

OBJECTIVE

Syndromes causing mechanical low back pain (MLBP) continue to plague the US health care system. One hypothesis is that flatfeet are a risk factor for MLBP. This pilot study evaluated whether subjects with flatter feet are at greater risk for MLBP than subjects without flatter feet.

METHODS

Fifty-eight subjects (16-70 years old) were allocated to a group diagnosed with 2 or more episodes of MLBP or with no history of MLBP. A blind assessor measured navicular drop (ND) using navicular height (NH) and calcaneal eversion (CE). Based on a range of reported data, flatfoot was defined as a possible risk factor for MLBP with ND greater than 3, 8, and/or 10 mm, and/or greater than 6 degrees CE.

RESULTS

According to chi2 analysis, risk of MLBP appeared similar between groups (P > .05). There was no significant difference (P > .05) between continuous variables (t tests, Pearson r and r2) with one exception, correlation of increasing CE with increasing ND (P = .0001). Power was generally low (<0.80). Likelihood ratios and Fisher exact tests supported the chi2 analysis.

CONCLUSIONS

In this study, flatfeet did not appear to be a risk factor in subjects with MLBP. However, small sample size, low power, broader age range, low prevalence of flatfeet (>10 mm ND), and lesser back pain severity make these data tentative. Further research is needed.

Effect of foot shape on the three-dimensional position of foot bones

To eliminate some of the ambiguity in describing foot shape, we developed three-dimensional (3D), objective measures of foot type based on computerized tomography (CT) scans. Feet were classified via clinical examination as pes cavus (high arch), neutrally aligned (normal arch), asymptomatic pes planus (flat arch with no pain), or symptomatic pes planus (flat arch with pain). We enrolled 10 subjects of each foot type; if both feet were of the same foot type, then each foot was scanned (n=65 total). Partial weightbearing (20% body weight) CT scans were performed. We generated embedded coordinate systems for each foot bone by assuming uniform density and calculating the inertial matrix. Cardan angles were used to describe five bone-to-bone relationships, resulting in 15 angular measurements. Significant differences were found among foot types for 12 of the angles. The angles were also used to develop a classification tree analysis, which determined the correct foot type for 64 of the 65 feet. Our measure provides insight into how foot bone architecture differs between foot types. The classification tree analysis demonstrated that objective measures can be used to discriminate between feet with high, normal, and low arches.

Incidence of foot and ankle injuries in West Point cadets with pes planus compared to the general cadet population

BACKGROUND

The relationship between pes planus and injuries of the lower extremity is controversial. However, few studies have used standardized means of evaluating and defining pes planus, and none have had a controlled patient population. The objective of this study was to evaluate an ideal population of physically active individuals to establish a potential correlation between pes planus, as defined by a standardized method, and injuries to the lower extremity.

METHODS

A standardized technique for evaluating arch height, based on a midfoot ratio established by Harris mat print calculations, was used to assess a consecutive series of 512 newly entered West Point cadets. Pes planus was defined as more than 2 standard deviations above the mean midfoot ratio of the population. After 46 months, a retrospective chart review was done to identify lower extremity injuries sustained in this group of young healthy patients. The results of the footprint analysis were correlated with the medical record findings.

RESULTS

Thirty-three cadets were found to have pes planus; 13 had only left foot involvement, 15 had right foot only involvement, and five had bilateral pes planus. There were no cavus feet. Statistically significant relationships were seen between the degree of pes planus and total number of injuries sustained (p = 0.007), the overall size of the foot and total number of injuries (p = 0.041), left flat feet and left midfoot injuries (p = 0.028), left pes planus and right midfoot injuries (p = 0.008), left pes planus and left knee injuries (p = 0.038), and right pes planus and right knee injuries (p = 0.027). Women had smaller feet (p = 0.000), smaller midfoot ratios (right, p = 0.013; left p = 0.003), yet they had an increased number of injuries (Pearson's coefficient -0.119; p = 0.007).

CONCLUSIONS

The current study found significant relationships between pes planus and number of injuries sustained over a 4-year period at West Point. While women were found to have smaller feet and lesser degrees of pes planus, they sustained more injuries than men.

Validity of 3 clinical techniques for the measurement of static foot posture in older people

STUDY DESIGN

Concurrent validity study.

OBJECTIVES

To determine the validity of 3 clinical methods for assessing static foot posture in older people.

BACKGROUND

Variations in the structure of the medial longitudinal arch are thought to influence lower extremity function; however, the validity of clinical measurements has not been fully established.

METHODS AND MEASURES

Clinical measurements of arch index (AI), navicular height (NH), and Foot Posture Index (FPI) were performed on 95 subjects (31 men and 64 women), aged 62 to 94 years (mean +/- SD, 78.6 +/- 6.5 years). These clinical measurements were then correlated with 3 arch-related measurements from radiographs: navicular height (NHr), calcaneal inclination angle (CIA), and calcaneal first metatarsal angle (C1MA).

RESULTS

All 3 clinical measures demonstrated significant associations with each of the radiographic parameters (P<.01). NH was highly correlated with NHr (Pearson r = 0.79), followed by C1MA (r = -0.53), and CIA (r = 0.44). The AI was highly correlated with the C1MA (r = 0.71) and CIA (r = -0.68), but only moderately correlated with NHr (r = 0.52). The FPI demonstrated weaker correlations with the radiographic parameters (NHr, r = 0.59; CIA, r = 0.36; C1MA, r = 0.42).

CONCLUSION

Clinical measurements of AI, NH, and FPI provide valid information regarding the structure of the medial longitudinal arch; however, each test may reflect different aspects of arch structure. NH would appear to be the most useful clinical measure, as it is simple to perform and provides an accurate representation of the skeletal alignment of the medial longitudinal arch. Further refinement of the clinical measurement of NH is now required to improve its moderate intratester and intertester reliability.

Comparison of results of clinicians' assessments, cytologic examination of fine-needle lymph node aspirates, and flow cytometry for determination of remission status of lymphoma in dogs

OBJECTIVE

To determine interclinician agreement when assessing remission of lymphoma in dogs and the association among results of clinicians' assessments via lymph node palpation, cytologic examination of fine-needle lymph node aspirates, and flow cytometry as determinants of remission.

DESIGN

Prospective study.

ANIMALS

23 dogs with untreated lymphoma. PROCEDURE; Two clinicians independently measured large lymph nodes and cytologic examination and flow cytometry of cells from a mandibular or popliteal lymph node were performed 1 week prior to initiating treatment. Lymph node measurements with clinicians' remission assessments and cytologic examination were repeated at weeks 2, 3, and 5; flow cytometry was repeated at week 5.

RESULTS

Significant correlation was identified between clinicians' remission assessments. Significant correlation between lymph node palpation and cytologic examination was identified at week 5, but not at weeks 2 and 3. Lymphoma was diagnosed in 16 of 23 (70%) dogs at initial evaluation by use of flow cytometry, although it was of limited use at subsequent evaluations and results were not diagnostic of lymphoma in any dog at week 5, including 1 dog in which lymphoma was diagnosed cytologically.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that physical examination and measurement of lymph node volume may not be sufficient for accurately determining remission, that flow cytometry alone should not be relied on as a means for diagnosis, and that cytologic examination of fine-needle lymph node aspirates should be considered as the most accurate means of determining remission status at times in which treatment modifications are considered.

Image analysis system for acquiring three-dimensional contour of foot arch during balanced standing

Compared to the X-ray approach, footprint analysis is a non-radiation and more viable method for clinical assessment of the medial longitudinal arch of the foot. In this study, we have designed an optical footprint acquisition system that consists of a digital camera and two pieces of glass, each with four load cells under each corner. When the subject stands on the transparent force plates, the digital camera is triggered, photographing the soles of the feet at the moment when both feet bear approximately at the same weight. A blue gel is placed between the foot and the force plate to enhance the contrast between sole and background. Based on the relationship between the brightness of the image and the thickness of the gel, the three-dimensional (3D) structure of the arch can be reconstructed which can provide more representative information than a conventional footprint image, with its low resolution and easy smearing.

Biomechanical differences among pes cavus, neutrally aligned, and pes planus feet in subjects with diabetes

The purpose of this study was to quantify differences in joint range of motion, foot deformity, and foot morphology among pes cavus, neutrally aligned, pes planus rigid, and pes planus flexible feet. A cohort of 1047 veterans with diabetes (contributing 2047 feet) was enrolled in a prospective study of diabetic ulcer risk factors (the Seattle Diabetic Foot Study). Significant differences between foot types were found. Pes cavus feet had an increased percentage of prominent metatarsal heads, bony prominences, and hammer/claw toes (p < .0001), as well as significantly increased amounts of hallux dorsiflexion and decreased amounts of hallux plantarflexion (p < .0001) with a total range of motion equal to the other foot types (p = .3). Neutrally aligned feet had a lower percentage of intrinsic muscle atrophy, bony prominences, and hammer/claw toes (p < .0001). Pes planus feet had an increased lateral talometatarsal angle (p < .0001) and an increased second metatarsal length. These data demonstrate structural differences between foot types in a population with diabetes.

The injury risk associated with pes planus in athletes

Despite the common prophylactic use of rigid orthotics in athletes with flat feet to prevent subsequent injury, there is little scientific data in the literature examining the relationship between pes planus and athletic injuries to the lower extremity. The current prospective study was undertaken to establish what relationship, if any, exists between foot morphology and subsequent lower extremity injury. A total of 196 subjects were enrolled in the study, of which 143 (73%) were male and 53 (27%) were female. Forty-two percent of the participants (83) engaged in contact sports. There were a total of 227 episodes of injury involving the lower extremity. Logistic regression using contact sports, gender, and all of the different foot contact areas that were measured at the beginning of the study was undertaken. Although gender and participation in contact sports was predictive of some lower extremity injuries, the existence of pes planus as measured by medial midfoot contact area as a percentage of total contact area was not a risk factor for any injury of the lower extremity. This study shows that in an athletic population that is representative of collegiate athletics, the existence of flat footedness does not predispose to subsequent lower extremity injury. The routine prophylactic use of orthotics in flat-footed athletes to prevent future injury may therefore not be justified based on the data available.

Foot type classification: a critical review of current methods

Investigation into the effects of foot structure on foot function, and the risks of injury, has been at the core of many studies, sometimes with conflicting results. Often different methods of foot type classification have been used, making comparison of the results and drawing sound conclusions impossible. This article aims to critically review current methods of foot type classification. It is concluded that if a classification method combines data on structure with information on foot function in dynamic loading situations, it should relate more closely to the functional behaviour of the foot during locomotion.

The measurement of the medial longitudinal arch in children

Both feet of two hundred and seventy two children aged between five years six months and ten years and eleven months were studied using a footprint technique called the arch index (Al), and the vertical height of the navicular (NH) as non invasive techniques of objective measures of the medial longitudinal arch (MLA). In addition to age the study investigated the influence of gender, limb dominance, and body weight. The study found the existence of a relationship between the two measures of the MLA. There was no significant difference in NH measures between males and females and body weight did not affect the NH. The NH changed with age, suggesting it provides a useful, easily obtained clinical measure. The Al measures were slightly more reliable than the NH but showed less change with age.

Arch structure and injury patterns in runners

OBJECTIVE

The purpose of this study was to determine if high-arched and low-arched runners exhibit different injury patterns.

DESIGN

Non-randomized, two-group injury survey.

BACKGROUND

Running-related injuries are thought to be related, in part, to lower extremity structure. High-arched and low-arched runners with their different bony architecture may exhibit very different lower extremity mechanics and, consequently, different injury patterns. It was hypothesized that high-arched runners will exhibit a greater incidence of lateral injuries, skeletal injuries and knee injuries while low-arched runners will show a greater incidence of medial injuries, soft tissue injuries and foot injuries.

METHODS

Twenty high-arched and 20 low-arched runners were included in this study. Running-related injuries were recorded and divided into injury patterns of medial/lateral, bony/soft tissue and knee/foot and ankle for both high-arched and low-arched runners. A chi(2) analysis was then employed in an attempt to associate injury patterns with arch structure.

RESULTS

High-arched runners reported a greater incidence of ankle injuries, bony injuries and lateral injuries. Low-arched runners exhibited more knee injuries, soft tissue injuries and medial injuries.

CONCLUSIONS

Based on these results, high and low arch structure is associated with different injury patterns in runners. Relevance. Different injury patterns are present in individuals with extreme high arches when compared to those with extremely low arches. These relationships may lead to improved treatment and intervention strategies for runners based on their predisposing foot structure.

Biomechanics of procedures used in adult flatfoot deformity

A flatfoot deformity can occur secondary to fairly obvious causes, or more subtle and less definable entities. Complicating the situation further, it is likely that the cause of an acquired flatfoot deformity in an adult is multifactorial. This likelihood makes the definition, diagnosis, and appropriate treatment of this condition a daunting task. More research is needed to define further the biomechanics of the foot and to understand the significance of the forces that combine to create flatfoot deformity.

Measurements Used to Characterize the Foot and the Medial Longitudinal Arch: Reliability and Validity

Background and Purpose. Abnormality in the structure of the medial longitudinal arch of the foot is commonly thought to be a predisposing factor to injury. The purpose of this investigation was to compare the reliability and validity of several measurements used to characterize various aspects of the foot, including the medial longitudinal arch. Subjects. One hundred two feet (both feet of 51 subjects) were measured to establish a reference database. From this group, a subset of 20 feet (both feet of 10 subjects) was used to determine intertester and intratester reliability. Radiographs of a further subset of 10 feet (right feet of 10 subjects) were used to determine validity. Methods. Five foot measurements were taken in 2 stance conditions: 10% of weight bearing and 90% of weight bearing. Results. Intraclass correlation coefficients (ICCs) for intertester and intratester measurements were between .480 and .995. The most reliable method of characterizing arch type in 10% of weight bearing between testers was dividing navicular height by foot length in 10% of weight bearing. However, this measure yielded highly unreliable measurements in 90% of weight bearing. The most valid measurements were navicular height divided by truncated foot length, navicular height divided by foot length in 10% of weight bearing, and navicular height divided by foot length in 90% of weight bearing. Dorsum height at 50% of foot length divided by truncated foot length showed relatively high intertester reliability (ICC=.811 in 10% of weight bearing, ICC=.848 in 90% of weight bearing) and validity (ICC=.844 in 10% of weight bearing, ICC=.851 in 90% of weight bearing). Conclusion and Discussion. These data suggest that, of the measures tested, the most reliable and valid method of clinically assessing arch height across 10% and 90% of weight bearing was dividing the dorsum height at 50% of foot length by truncated foot length.

Subluxation of the talocalcaneal joint in adults who have symptomatic flatfoot

BACKGROUND

When flatfoot is acquired during adulthood, the shape of the foot changes. In addition to a decreased arch, there may be valgus angulation of the hindfoot or abduction of the forefoot, or both. However, there is little objective information to provide a better understanding of the anatomical or morphological changes that occur in acquired adult flatfoot. We wondered if such an understanding of the three-dimensional anatomy might shed light on the pathway by which these changes occur. We designed this study to measure the three-dimensional position of the talocalcaneal joint in patients who have painful flatfoot.

METHODS

Computed tomography scans of the feet of eight patients who had symptomatic flatfoot were used to construct a model of the talocalcaneal articulation. The scans were performed on a custom loading frame developed to simulate weight-bearing with the foot in a neutral position while a seventy-five-newton axial compressive load was applied. The digital data from the scans were used to make three-dimensional computer models of the articular surfaces of the talus and calcaneus of each foot. These models then were used to calculate the percentage of the articular surface that was in contact and, conversely, the percentage that was subluxated. Two surfaces were modeled for each bone; the posterior facet formed one surface, and the anterior and middle facets were combined to form the second surface. The data were compared, with use of Mann-Whitney nonparametric U analysis, with those derived from scans of the feet of four patients without a deformity of the hindfoot who served as controls.

RESULTS

A mean (and standard deviation) of 68+/-9 percent of the posterior facet of the calcaneus was in contact with the talus in the patients who had flatfoot compared with 92+/-2 percent in the controls, and a mean of 51+/-23 percent of the anterior and middle facets of the calcaneus was in contact with the talus in the patients who had flatfoot compared with 95+/-6 percent in the controls. These differences were significant (p = 0.0066 for both).

CONCLUSIONS

Marked subluxation of the talocalcaneal joint occurs in some patients who have symptomatic planoabductovalgus deformity.

Defining flatfoot

Pes planus is a term frequently used in describing flatfoot; however, no study has objectively defined flatfoot. We evaluated the single leg stance footprint of 40 feet in 21 people with no history of foot problems, using pressure-sensitive film and a Harris mat. The medial and lateral aspects of the forefoot, midfoot, and hindfoot were assessed. The midfoot was further analyzed by dividing the medial midfoot force by the total midfoot force. The mean medial midfoot force/total midfoot force was 11.1% (SD = 6.5%). Pes planus was defined as the medial midfoot force/total midfoot force > 24.0% (mean + 2 SD). A population associated with pes planus (124 feet in 63 patients with Marfan syndrome) was then evaluated in the same fashion. Although the mean medial midfoot force/total midfoot force was not statistically different (16.0%), a distinct group of patients (25%) had forces that were outside the range of normal midfoot forces.

Measurement of the medial longitudinal arch

Although clinical evidence suggests a causal relationship between arch structure and musculoskeletal injury patterns, biological variations in soft-tissue structures effect the accuracy of arch-height measurements. Medial longitudinal arch (MLA) structure was assessed clinically and radiographically in 100 consecutive patients with foot problems. Intraclass correlation coefficients were calculated for three radiographic parameters and three anthropometric parameters of the MLA. Intrarater and interrater reliability estimates for the radiographic measurements were uniformly excellent. Intrarater reliability coefficients were higher than interrater coefficients for the three tested anthropometric parameters. The strengths of associations between anthropometric and radiographic data were assessed with Pearson correlation coefficients. The clinically determined ratio of navicular height-to-foot length correlated most closely with the radiographic indices of MLA structure.