3-dimensional Foot Research Articles

Change of Segmental Motion Following Total Ankle Arthroplasty Using a 3-Dimensional Multi-segment Foot Model.

Total ankle arthroplasty (TAA) enhances patients' subjective outcomes with respect to pain and function. The aim of this study was to analyze the biomechanical changes of the affected limb following TAA using gait analysis with a 3-dimensional multi-segment foot model (3D MFM). We reviewed medical records, simple radiographs, and gait analyses using a 3D MFM of patients who underwent TAA for severe varus ankle arthritis. Preoperative and postoperative gait data of 24 patients were compared. Postoperative gait analyses were done at least 1 year after surgery. TAA significantly increased stride length (p = 0.024). The total range of motion of all planes in the hindfoot and forefoot showed no significant changes between preoperative and postoperative states. Hindfoot was significantly plantarflexed and pronated after TAA, while forefoot was significantly supinated in all phases. After appropriate calculations, the genuine coronal motion of the hindfoot showed no changes after TAA in all phases. TAA did not result in biomechanical improvements of segmental motions in the forefoot and hindfoot, except for changes to the bony structures. Therefore, it is important to point out to patients that TAA will not result in significant improvement of ankle function and range of motion. Clinicians can consider this information during preoperative counseling.

Effects of 10KM run on foot morphology and bilateral symmetry in male recreational runners.

Foot morphology and arch integrity do not remain constant during a running bout. Previous studies have reported inconsistent changes in foot sizes and arch parameters and this discrepancy may be related to the variation in their test duration, e.g., 15-min treadmill run vs. 30KM trial. Hence, this study sought to evaluate the change in foot morphology, arch integrity and bilateral symmetry after a 10KM run among 19 male recreational runners. Before and after the run, a portable foot scanner was used to capture the 3-dimensional foot images and measure foot dimensions in both weight-bearing and non-weight-bearing conditions. Foot arch integrity was quantified by arch height ratio, arch height index, and arch stiffness index (ASI). Bilateral symmetry was evaluated by calculating the symmetry index. Increased foot length (p = 0.007; = 0.18) and decreased ball girth (p = 0.038; = 0.11) were demonstrated following the run with absolute differences of less than 2mm. Navicular height, dorsum height, arch height ratio and arch height index significantly decreased after the run (p < 0.001; ≥0.30) whereas ASI increased (p < 0.001, = 0.33) and navicular height drop reduced (p < 0.001, = 0.37). Significances of symmetry index were only demonstrated for navicular height (p = 0.019, effect size = 0.37) and arch height ratio (p = 0.019, effect size = 0.42). A few changes in foot morphology were detected but a reduction in foot arch height was demonstrated, which may give shoe manufacturers insights into shoe design. Male recreational runners were recommended to choose shoes with arch support for maintaining foot arch function during a 10KM run.

Ankle Joint Bone Density Distribution Correlates with Overall 3-Dimensional Foot and Ankle Alignment.

Altered stress distribution in the lower limb may impact bone mineral density (BMD) in the ankle bones. The purpose of the present study was to evaluate the spatial distribution of BMD with use of weight-bearing cone-beam computed tomography (WBCT). Our hypothesis was that BMD distribution would be even in normal hindfeet, increased medially in varus hindfeet, and increased laterally in valgus hindfeet. In this study, 27 normally aligned hindfeet were retrospectively compared with 27 valgus and 27 varus-aligned hindfeet. Age (p = 0.967), body mass index (p = 0.669), sex (p = 0.820), and side (p = 0.708) were similar in the 3 groups. Hindfoot alignment was quantified on the basis of WBCT data sets with use of multiple measurements. BMD was calculated with use of the mean Hounsfield unit (HU) value as a surrogate. The HU medial-to-lateral ratio (HUR), calculated from tibial and talar medial and lateral half-volumes, was the primary outcome of the study. The 3 groups significantly differed (p < 0.001) in terms of tibial HUR (median, 0.91 [interquartile range (IQR), 0.75 to 0.98] in valgus hindfeet, 1 [IQR, 0.94 to 1.05] in normal hindfeet, and 1.04 [IQR, 0.99 to 1.1] in varus hindfeet) and talar HUR (0.74 [IQR, 0.50 to 0.80] in valgus hindfeet, 0.82 [IQR, 0.76 to 0.87] in normal hindfeet, and 0.92 [IQR, 0.86 to 1.05] in varus hindfeet). Linear regression showed that all hindfoot measurements significantly correlated with tibial and talar HUR (p < 0.001 for all). The mean HU values for normally-aligned hindfeet were 495.2 ± 110 (medial tibia), 495.6 ± 108.1 (lateral tibia), 368.9 ± 80.3 (medial talus), 448.2 ± 90.6 (lateral talus), and 686.7 ± 120.4 (fibula). The mean HU value for each compartment was not significantly different across groups. Hindfoot alignment and medial-to-lateral BMD distribution were correlated. In varus hindfeet, an increased HU medial-to-lateral ratio was consistent with a greater medial bone density in the tibia and talus as compared with the lateral parts of these bones. In valgus hindfeet, a decreased ratio suggested greater bone density in the lateral as compared with the medial parts of both the tibia and the talus. Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Regional plantar forces and surface geometry variations of a chronic ankle instability population described by statistical shape modelling

BackgroundUnderstanding detailed foot morphology as well as regional plantar forces could provide insight into foot function and provide recommendation for footwear design for chronic ankle instability (CAI) people. Research QuestionThis study presented 3-dimensional statistical shape models of feet from three different populations including CAI, copers and healthy individuals, with regional plantar forces also acquired. MethodsSixty-six males (22 participants per group) were included in this study to capture 3-dimensional foot shapes under a standing condition and regional plantar forces during a cutting maneuver. Principal component analysis was performed to generate a mean foot shape of each group as well as modes of variations. A generalized procrustes analysis was used to achieve rapid registration of mean shapes. Besides, regional plantar forces and contact duration among these three populations were compared. ResultsFor 3-dimensional foot shapes, although no significant differences of the average distance between each mode and mean shape were found among three populations, there were subtle variations in mean shapes. The CAI population presented a more bulging of the lateral malleolus; copers were characterized by the flexion of the lesser toes, a more bulging of the medial foot in the sagittal plane; and healthy individuals showed a greater heel width and a more bulging of the heel in the sagittal plane. In terms of plantar forces, healthy individuals had significantly greater summated plantar forces and greater plantar forces in the lateral heel area during the early contact phase compared to copers and CAI participants. SignificanceOverall, this study suggested that repetitive ankle sprains may lead to the bulging of the lateral malleolus. Further, CAI and copers seem to stabilize the ankle joint by medially shifting the center of pressure compared to healthy individuals under the static and less challenging dynamic conditions.

Radiographic Measurements Associated With Ankle Power Generation During Gait in Patients With Cerebral Palsy.

Pes planovalgus (PV) deformity accounts for lever arm dysfunction and compromises gait in patients with cerebral palsy (CP). However, the association between ankle power generation and radiographic indices is not yet understood. We aimed to investigate the association between ankle power and radiographic indices during gait in patients with CP concomitant with PV deformity. Patients older than 14 years with ambulatory CP and PV deformity were included. All the patients underwent 3-dimensional gait analysis and weight-bearing foot radiography. Gait data were collected, including foot progression angle, tibial rotation, hip rotation, and ankle power generation. Radiographic measurements included anteroposterior (AP) talo-first metatarsal angle, lateral talo-first metatarsal angle, and hindfoot angle. A linear mixed-effects model was performed to identify significant radiographic indices associated with ankle power generation. Thirty-one limbs from 15 patients with spastic diplegia and 6 with spastic hemiplegia were included. Statistical analysis demonstrated that ankle power generation was significantly correlated with the CP type ( P =0.0068) and AP talo-1 st metatarsal angle ( P =0.0230). Ankle power generation was significantly associated with the AP talo-first metatarsal angle. Surgeons might need to pay attention to correcting forefoot abduction to restore ankle power when planning surgeries for pes PV deformities in patients with CP. Prognostic Level III.

The improved approach to the development of parameters for the inner shape of military boots

In the work, anthropometric studies of the feet were performed by means of 3D scanning. The results of scanning have been used for two main purposes. Firstly, the features and morphological structure of the feet of young men aged 20-30 were studied, who are the representatives of the Ukrainian population that are subject to mobilization into the ranks of the Armed Forces. Apart from this, the quantitative distribution of the main morphological features of the feet of the sample population was analyzed. During measurements, it was noticed that a large number of men had hypertrophy of the heads of the 1st and 5th metatarsal bones. In order to rationalize the range of lasts with different sizes and fullness, while trying to fully satisfy the requirements of compliance with the anthropometric parameters of the feet of consumers, the parameters of the feet with the hypertrophy of the heads of the 1st and 5th metatarsal bones must be taken into account in the lasts with increased width. Furthermore, the results of scanning constitute the basis for calculating and developing basic parameters of lasts. For this, the work suggested the method of designing a last shape based on such types of input data as a digital foot model, dimensional foot parameters, and a foot print obtained as a result of mass 3D scanning of the feet.

Differences in Gait and Stair Ascent After Total Ankle Arthroplasty and Ankle Arthrodesis.

Ankle arthrodesis has historically been the standard of care for end-stage ankle arthritis; however, total ankle arthroplasty (TAA) is considered a reliable alternative. Our objective was to compare 3-dimensional foot and ankle kinetics and kinematics and determine the ankle power that is generated during level walking and stair ascent between TAA and ankle arthrodesis patients. Ten patients who underwent TAA with a modern fixed-bearing ankle prosthesis and 10 patients who previously underwent ankle arthrodesis were recruited. Patients were matched for age, sex, body mass index, time from surgery, and preoperative diagnosis. A minimum of 2-year follow-up was required. Patients completed instrumented 3D motion analysis while walking over level ground and during stair ascent. Between-group differences were assessed with a 2-tailed Mann-Whitney exact test for 2 independent samples. Sagittal ankle range of motion (ROM) was significantly higher in the TAA group (21.1 vs 14.7 degrees, P = .003) during level walking. In addition, forefoot-tibia motion (25.3±5.9 degrees vs 18.6±5.1 degrees, P = .015) and hindfoot-tibia motion (15.4±3.2 degrees vs 12.2±2.5 degrees, P = .022) were significantly greater in the TAA group. During stair ascent, sagittal ankle ROM (25 vs 17.1 degrees, P = .026), forefoot-tibia motion (27.6 vs 19.6 degrees, P = .017), and hindfoot-tibia motion (16.8 vs 12 degrees, P = .012) was greater. There were significant differences during level walking and stair ascent between patients with TAA and ankle arthrodesis. TAA patients generated greater peak plantarflexion power and sagittal motion within the foot and ankle compared to patients with an ankle arthrodesis. Further investigation should continue to assess biomechanical differences in the foot and ankle during additional activities of daily living. Level III, comparative study.

The quarter-ellipsoid foot: A clinically applicable 3-dimensional composite measure of foot deformation during weight bearing

Study DesignDescriptive Laboratory ObjectivesTo assess change in foot morphology across loading using innovative, clinically accessible 3-dimesional composite measurements of surface area (SA), volume (V), and SA:V ratio in recreationally-active young adults. MethodsThe feet of 53 female [mean age:20.7 ± 3.8 years, BMI:23.9 ± 4.2 kg m−2, foot posture index (FPI):3.8 ± 3.7] and 31 male participants (mean age:20.8 ± 2.4 years, BMI:23.7 ± 2.5 kg m−2, FPI:3.8 ± 4.1) were evaluated. FPI was assessed and foot length, width, and dorsal arch height were measured in sitting and bipedal standing and used to calculate the SA and V of a quarter-ellipsoid. ΔSA characterized foot widening and lengthening and ΔV characterized arch deformation during loading. The SA:V represented changes in both foot size and shape. Linear regression was performed to assess the effects of component foot change measures during loading on the composite measurements. The composite measures were compared to the established measures of ΔArch Height Index (ΔAHI), Arch Flexibility, Foot Mobility Magnitude (FMM), and FPI. ResultsFoot width and dorsal arch height change measures were significant predictors (p < 0.001) for the ΔV and SA:V composite measures, explaining 90–91% of the variance. Significant fair to good associations (p < .05) were found between the novel and established composite measures: ΔSA: Arch flexibility (r=-0.27); SA:V: ΔAHI (r=-0.57), Arch Flexibility (r=-0.75), FMM (r=-0.30), FPI (r = 0.42). ConclusionQuarter-ellipsoid measures calculated from morphologic measurements may have clinical utility in quantifying 3-dimensional foot changes during loading and may be useful when assessing need and response to clinical interventions.

Subject-specific identification of three dimensional foot shape deviations using statistical shape analysis

The high prevalence of foot pain, and its relation to foot shape, indicates the need for an expert system to identify foot shape abnormalities. Yet, to date, no such expert system exists that examines the full 3D foot shape and produces an intuitive explanation of why a foot is abnormal. In this work, we present the first such expert system that satisfies those goals. The system is based on the concept of model-based outlier detection: a statistical shape model (SSM) is generated from 186 3D optical foot scans of healthy feet. This model acts as a knowledge base which is then parameterized by one’s demographic characteristics (e.g., age, weight, height, shoe size) through a multivariate regression. This regression introduces model flexibility as it allows the model to be fine tuned to a specific individual. This fine tuned model is then used as a baseline to which the individual’s 3D foot scan can be compared using standard statistical tests (e.g. t-tests). These statistical tests are performed at each vertex along the foot surface to identify the degree and location of shape outliers. Our expert system was validated on foot scans from patients with hallux valgus and abnormal foot arches. As expected, our results varied per patient, confirming that feet with the same clinical classification still show high shape variability. Additionally, the foot shape abnormalities identified by our system not only agreed with the expected location and severity of the tested foot deformities, but our analysis of the full 3D foot shape was able to completely characterize the extent of those abnormalities for the first time. These results show that the combination of statistical shape modelling, multivariate regression, and statistical testing is powerful enough to perform outlier detection for 3D foot shapes. The resulting insights provided by this system could prove useful in both shoe design and clinical diagnosis.

Association of Arch Stiffness with Plantar Impulse Distribution during Walking, Running, and Gait Termination.

The purpose of this study was to determine relationships between arch stiffness and relative regional impulse during walking, running, and stopping. A total of 61 asymptomatic male subjects volunteered to participate in the study. All were classified by calculating the arch stiffness index using 3-dimensional foot morphological scanning. Plantar pressure distribution data were collected from participants using a Footscan pressure platform during gait tests that included walking, running, and gait termination. The stiff arches group (n = 19) and flexible arches group (n = 17) were included in the following data analysis. The results suggested that subjects with stiffer arches had a larger and smaller percentage of plantar impulse in the forefoot and rearfoot, respectively, than subjects with more flexible arches during walking and running. However, during gait termination, which included planned and unplanned gait stopping, the plantar impulse distribution pattern was found to be reversed. The current findings demonstrate that the distributional changes of plantar loading follow unidirectional transfer between the forefoot and the rearfoot on the plantar longitudinal axis. Moreover, the patterns of impulse distribution are also different based on different gait task mechanisms.

Reproducibility of foot dimensions measured from 3-dimensional foot scans in children and adolescents with Down syndrome

BackgroundChildren and adolescents with Down syndrome have a distinctive foot shape (such as wide and flat feet) that often leads to difficulty with footwear fitting. 3-dimensional (3D) scanning can accurately measure the foot dimensions of individuals with Down syndrome, which may assist shoe fit. However, the reproducibility of measuring foot dimensions using 3D scans in children and adolescents with Down syndrome is unknown. The aim of this study was to determine the intra- and inter-rater reproducibility of measuring foot dimensions of children and adolescents with Down syndrome using 3D scanning.Methods3D foot scans of 30 participants with Down syndrome aged 5 to 17 years were obtained using the FotoScan 3D scanner. Foot dimensions assessed were foot length, ball of foot length, outside ball of foot length, diagonal foot width, horizontal foot width, heel width, ball girth, instep girth, first and fifth toe height, and instep height. Additionally, the Wesjflog Index and forefoot shape were determined. Measurements were completed by two raters independently on two separate occasions, 2 weeks apart. Intra- and inter-rater reliability were assessed using intra-class coefficients (ICCs) and Gwet’s AC1 statistics with 95% confidence intervals. Agreement was determined by calculating limits of agreement (LOA) and percentage agreement.ResultsEighteen participants were female and 12 were male (mean age 10.6 [3.9] years). Intra-rater reproducibility (ICCs ranged from 0.74 to 0.99, 95% LOA from − 13.7 mm to 16.3 mm) and inter-rater reproducibility (ICCs ranging from 0.73 to 0.99, 95% LOA from − 18.8 mm to 12.7 mm) was good to excellent, although some measurements (ball of foot length, outside ball of foot length, heel width and girth measurements) displayed wider LOAs indicating relatively poorer agreement. Forefoot shape displayed substantial to almost perfect reliability (Gwet’s AC1 0.68 to 0.85) and percentage agreement ranged from 73 to 87%, indicating acceptable agreement.ConclusionsThe measurement of specific foot dimensions of children and adolescents with Down syndrome using 3D scans is reproducible. Findings of this study may be used to support future research measuring specific foot dimensions of children and adolescents with Down syndrome using 3D foot scans.

Analysis of the main passive soft tissues associated with adult acquired flatfoot deformity development: A computational modeling approach

Adult acquired flatfoot deformity (AAFD) is a pathology with a wide range of treatment options. Physicians decide the best treatment based on their experience, so the process is entirely subjective. A better understanding of soft tissue stress and its contribution in supporting the plantar arch could help to guide the clinical decision. Traditional experimental trials cannot consistently evaluate the contribution of each tissue. Therefore, in this research a 3-Dimensional FE foot model was reconstructed from a normal patient in order to measure the stress of the passive stabilizers of the arch, and its variation in different scenarios related with intermediate stages of AAFD development. All bones, the plantar fascia (PF), cartilages, plantar ligaments and the spring ligament (SL) were included, respecting their anatomical distribution and biomechanical characteristics. An AAFD evaluation scenario was simulated. The relative contribution of each tissue was obtained comparing each result with a normal case. The results show that PF is the main tissue that prevents the arch elongation, while SL mainly reduces the foot pronation. Long and short plantar ligaments play a secondary role in this process. The stress increment on both PF and SL when one of two fails suggests that these tissues complement each other. These findings support the theory that regards the tibialis posterior tendon as a secondary actor in the arch maintenance, compared with the PF and the SL, because this tendon is overstretched by the hindfoot pronation around the talonavicular joint. This approach could help to improve the understanding of AAFD.

Kinematic foot types in youth with pes planovalgus secondary to cerebral palsy

BackgroundKinematic variability of the foot and ankle segments exists during ambulation among individuals with pes planovalgus (PPV) secondary to cerebral palsy (CP). Clinicians have previously recognized such variability through classification schemes to identify subgroups of individuals, but have been unable to identify kinematic foot types. Research questionThe purpose of this work was to identify kinematic foot types among children with PPV secondary to CP using 3-dimensional multi-segment foot and ankle kinematics during gait as inputs for principal component analysis (PCA) and K-means cluster analysis. MethodsIn a single assessment session, multi-segment foot and ankle kinematics using the Milwaukee Foot Model (MFM) were collected in 31 children/adolescents with pes planovalgus (49 feet) and 16 typically developing (TD) children/adolescents (31 feet). PCA was used as a data reduction technique on 34 kinematic variables. K-means cluster analysis was performed on the identified principal components (PCs) and one-way analyses of variance (ANOVA) was done to determine the effect of subgroup membership on PC scores. ResultsThe PCA reduced the kinematic variables to seven PCs which accounted for 91% of the total variance. Six distinct kinematic foot types were identified by the cluster analysis. The foot types showed unique kinematic characteristics in both the hindfoot and forefoot. SignificanceThis study provides further evidence of kinematic variability in the foot and ankle during ambulation associated with pes planovalgus secondary to CP. The specific contributions of the hindfoot and forefoot would not have been detected using a single segment foot model. The identification of kinematic foot types with unique foot and ankle characteristics has the potential to improve treatment since patients within a foot type are likely to benefit from similar intervention(s).

Association of Foot Structure with the Strength of Muscles that Move the Ankle and Physical Performance

The human foot plays an important role in supporting body weight, maintaining postural balance, and absorbing ground reaction forces. Although many studies have indicated that a causal relationship exists between foot structure and alterations in lower extremity kinematics, there is little evidence regarding the possible association of foot structure with strength of muscles that move the ankle and physical performance. A total of 67 adult men with a mean age of 51.19 ± 8.82 years participated in this study. Foot structural parameters were assessed using a 3-dimensional foot scanner. Strength of muscles that move the ankle was measured with a dynamometer. Physical performance items, including agility, force, and proprioception, were also measured. We found that all the measured parameters of the length, width, girth, and height of the foot were positively correlated with the strength of plantarflexion, dorsiflexion, eversion, and inversion (r ranged from 0.26 to 0.57; p < .05). Moreover, all or part of the parameters of the length, width, and girth of the foot but not the height and angles of the foot were correlated significantly with vertical jump, stepping forward and backward, and stepping side to side (r ranged from 0.25 to 0.44; p < .05). These findings indicate a weak-to-moderate association between foot structure and the strength of muscles that move the ankle, as well as physical performance. We therefore suggest that a larger foot may have greater muscle strength of the ankle joint and better physical performance.

Mild-to-Moderate Hallux Valgus Does Not Decrease Ankle Muscle Strength in Middle-Aged Japanese Women: A Comparative Study

Extreme hallux valgus has been documented to be related to lower functional ability and health-related quality of life. It also has a negative effect on foot structure and biomechanical characteristics, which in turn may affect muscle strength in the foot and ankle. Thus, the purposes of this study were to determine whether there is a difference of ankle muscle strength in varied hallux valgus deformities and to investigate correlations between hallux valgus angles and ankle muscle strength. Hallux valgus angles and ankle muscle strength data were collected from 31 middle-aged Japanese women. The hallux valgus angle was measured with a 3-dimensional foot scanner; ankle muscle strength was measured with a dynamometer. Results showed no differences in ankle muscle strength between normal and mild-to-moderate hallux valgus at both 60º/second and 120º/second (p > .05). Unexpectedly, women with mild-to-moderate hallux valgus had a greater value for inversion peak torque per body weight and eversion-to-inversion ratio than those with normal hallux valgus (p = .019 and p = .022) at 120º/second. Furthermore, hallux valgus was correlated with inversion peak torque and peak torque per body weight (r = 0.47; p = .012 and r = 0.50; p = .007) and associated with eversion-to-inversion strength ratio (r = –0.47; p = .012). The findings indicated that mild-to-moderate hallux valgus did not result in a decrease in ankle muscle strength. Conversely, mild-to-moderate hallux valgus had greater ankle inversion strength in middle-aged Japanese women. Further studies are needed to investigate ankle muscle strength in severe hallux valgus deformities.

Inertial Sensor-Based Gait and Attractor Analysis as Clinical Measurement Tool: Functionality and Sensitivity in Healthy Subjects and Patients With Symptomatic Lumbar Spinal Stenosis.

Objective: To determine if the attractor for acceleration gait data is similar among healthy persons defining a reference attractor; if exercise-induced changes in the attractor in patients with symptomatic lumbar spinal stenosis (sLSS) are greater than in healthy persons; and if the exercise-induced changes in the attractor are affected by surgical treatment.Methods: Twenty-four healthy subjects and 19 patients with sLSS completed a 6-min walk test (6MWT) on a 30-m walkway. Gait data were collected using inertial sensors (RehaGait®;) capturing 3-dimensional foot accelerations. Attractor analysis was used to quantify changes in low-pass filtered acceleration pattern (δM) and variability (δD) and their combination as attractor-based index (δF = δM* δD) between the first and last 30 m of walking. These parameters were compared within healthy persons and patients with sLSS (preoperatively and 10 weeks and 12 months postoperatively) and between healthy persons and patients with sLSS. The variability in the attractor pattern among healthy persons was assessed as the standard deviation of the individual attractors.Results: The attractor pattern differed greatly among healthy persons. The variability in the attractor between subjects was about three times higher than the variability around the attractor within subject. The change in gait pattern and variability during the 6MWT did not differ significantly in patients with sLSS between baseline and follow-up but differed significantly compared to healthy persons.Discussion: The attractor for acceleration data varied largely among healthy subjects, and hence a reference attractor could not be generated. Moreover, the change in the attractor and its variability during the 6MWT differed between patients and elderly healthy persons but not between repeated assessments. Hence, the attractor based on low-pass filtered signals as used in this study may reflect pathology specific differences in gait characteristics but does not appear to be sufficiently sensitive to serve as outcome parameter of decompression surgery in patients with sLSS.

Increasing Physical Activity Might Be More Effective to Improve Foot Structure and Function Than Weight Reduction in Obese Adults

Obesity is reported to be an important factor affecting foot structure and function. For obese individuals, weight reduction or increasing weight physical activity could be an effective approach to improve foot structure and function. The present study sought to determine the effect of weight reduction and increasing physical activity on foot structure and function in obese Japanese and to investigate which intervention is more beneficial. The participants were divided into the weight reduction group (n = 30; body mass index 29.0 ± 2.5 kg/m2), with the intervention consisting of dietary modification, and the increasing physical activity group (n = 15; body mass index 28.2 ± 3.1 kg/m2), with the intervention consisting of walking and jogging. A 3-dimensional foot scanner was used to measure the foot anthropometric data with the participants both sitting and standing. The dorsum height declined and the arch stiffness index increased after the weight reduction intervention, and the truncated foot length decreased and the arch stiffness index increased after the increasing physical activity intervention (p < .05). The arch height index showed a downward trend after the weight reduction intervention (p = .060) and an upward trend after the increasing physical activity intervention (p = .069). Moreover, a greater change was found in the increase of the dorsum height and arch height index and decrease of the truncated foot length in the increasing physical activity group than in the weight reduction group (p < .05). These findings suggest that increasing physical activity might be more effective to improve foot structure and function than weight reduction in obese adults.

Flexion location of the first metatarsophalangeal joint and the location of forefoot bend in general purpose women’s footwear

BackgroundGeneral purpose footwear could have a built-in flexion location which may not match the anatomical fulcrum location for an individual’s foot. Mismatched fulcra impact on joint function, and may delay healing of an injured first metatarsophalangeal joint (first MP joint). This study compared the location of the first MP joint in an asymptomatic sample of the South African female population to the bend location set within the lasts (used by footwear manufacturers) to find whether mismatches of the flexion locations of the joint to the bending location of the footwear were likely. MethodsThe study used a three dimensional foot measurement database of 453 female participants to find the fulcrum location of the first MP joint. The distance between the heel and the first MP joint was expressed as a percentage of the overall length of the unshod foot. Similar measures for sandals and closed shoes were derived, and all were compared to manufacturer last data. ResultsThe location of first MP joint ranged from 70% to 79% of total foot length, significantly different from last design specifications of 63% or 66% (p<0.0001). The range of first MP joint fulcrum locations in the same size feet occurred in a wide 24mm mediolateral band under the forefoot, termed a flexion zone. ConclusionsThe first MP joint cannot properly function as a fulcrum unless footwear has a matching flexion location. Footwear designs should incorporate a wide flexion zone located under the forefoot to permit the range of first MP joint flexion locations. Recommendations to patients are to select appropriate flexible footwear to prevent shear forces, reduce strain, prevent injury and enable range of motion function and healing of injury.

Does Weight Reduction Affect Foot Structure and the Strength of the Muscles That Move the Ankle in Obese Japanese Adults?

Obesity is considered a major influential factor of foot structure and function. It has been reported to result in detrimental alterations of foot structure indicators and a decrease in muscle strength, which can lower the quality of life and increase the morbidity of obesity. The purpose of the present study was to determine the effect of weight reduction on foot structure and the strength of the muscles that move the ankle in obese adults. A total of 33 obese Japanese participants (mean body mass index 28.49 ± 2.87 kg/m2) without an exercise habit participated in a 12-week dietary modification program. Their foot structure indicators were measured using a 3-dimensional foot scanner, and the strength of the muscles that move the ankle was assessed using a dynamometer. After the dietary modification, the mean body weight reduction was 7.49 ± 4.10 kg (9.38%; 77.82 ± 13.26 kg before and 70.33 ± 11.37 kg after; p < .001). The wide foot indicators, including the forefoot girth, rearfoot width, and instep girth, had decreased significantly (p < .05), and the decreases correlated positively with the weight reduction. Regarding the strength of the muscles that move the ankle, except for dorsiflexion, all the measured peak torque values per body weight had increased significantly (p < .01). These results suggest that the weight reduction induced by a 12-week dietary modification results in thinner feet and increased strength of the muscles that move the ankle.

Long-Term Effects of Orthoses Use on the Changes of Foot and Ankle Joint Motions of Children With Spastic Cerebral Palsy

BackgroundOrthoses commonly are prescribed to children with cerebral palsy (CP) to provide foot correction and to improve ambulatory function. Immediate effects of ankle foot orthosis (AFOs) have been investigated, but long-term kinematic effects are lacking clinical evidence. ObjectiveTo determine changes in 3-dimensional ankle and foot segment motion in pediatric patients with CP between initial and follow-up visits (18-month average time differences) in both barefoot gait and gait with their AFO. We also investigated intravisit changes between barefoot and AFO gait. DesignA prospective cohort study. SettingChildren’s Hospital of Wisconsin, Department of Orthopaedic Surgery, Medical College of Wisconsin. PatientsA total of 23 children with CP, mean age 10.5 years (6.2-18.1 years) were clinically prescribed either a solid ankle foot orthotic (SAFO), hinged ankle foot orthotic (HAFO), or supramalleolar orthotic. MethodsHoles were cut in the study orthoses so that electromagnetic markers could be directly placed on the skin. A 6-foot segment model was used. Outcome MeasurementsKinematic and kinetic data were recorded for each patient’s initial and follow-up visit (18-month follow-up average, 15-20 months range). ResultsFor the SAFO group (gait with AFO), a significant decrease in dorsiflexion was found between the initial and third visit (P = .008). Furthermore, the SAFO group (barefoot gait) had an increased eversion at the midfoot for most of the gait cycle (P < .008). Sagittal forefoot range of motion was reduced for all 3 groups between the barefoot and AFO groups. ConclusionThe use of AFOs long term either maintained or improved foot deformities or dysfunction. Level of EvidenceLevel II.