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

Ability of a multi-segment foot model to measure kinematic differences in cavus, neutrally aligned, asymptomatic planus, and symptomatic planus foot types

BACKGROUND

Multi-segment foot models (MFMs) provide a better understanding of the intricate biomechanics of the foot, yet it is unclear if they accurately differentiate foot type function during locomotion.

RESEARCH QUESTION

We employed an MFM to detect subtle kinematic differences between foot types, including: pes cavus, neutrally aligned, and asymptomatic and symptomatic pes planus. The study investigates how variable the results of this MFM are and if it can detect kinematic differences between pathologic and non-pathologic foot types during the stance phase of gait.

METHODS

Independently, three raters instrumented three subjects on three days to assess variability. In a separate cohort, each foot type was statically quantified for ten subjects per group. Each subject walked while instrumented with a four-segment foot model to assess static alignment and foot motion during the stance phase of gait. Statistical analysis performed with a linear mixed effects regression.

RESULTS

Model variability was highest for between-day and lowest for between-rater, with all variability measures being within the true sample variance. Almost all static measures (radiographic, digital scan, and kinematic markers) differed significantly by foot type. Sagittal hindfoot to leg and forefoot to leg kinematics differed between foot types during late stance, as well as coronal hallux to forefoot range of motion. The MFM had low between-rater variability and may be suitable for multiple raters to apply to a single study sample without introducing significant error. The model, however, only detected a few dynamic differences, with the most dramatic being the hallux to forefoot coronal plane range of motion.

SIGNIFICANCE

Results only somewhat aligned with previous work. It remains unclear if the MFM is sensitive enough to accurately detect different motion between foot types (pathologic and non-pathologic). A more accurate method of tracking foot bone motion (e.g., biplane fluoroscopy) may be needed to address this question.

Differences in the coordination and its variability among foot joints during running in neutral foot and flatfoot

Flatfoot is a well-known foot deformity, with a prevalence of 11.2%-29.0% among adults. Running injuries can occur in individuals with flatfoot; however, the underlying mechanism remains unknown. We investigated the coordination pattern and variability among foot joints while running by comparing participants with neutral foot and with flatfoot. Participants with neutral foot (n = 15) and flatfoot (n = 15) were asked to run at their preferred speed. Using the modified vector coding technique, the coupling angle between the foot joints, representing interjoint coordination, was calculated and categorized into four coordination patterns. The standard deviation of the coupling angle was computed to measure the coordination variability during the stance phase. There were no differences in the spatiotemporal parameters (speed, step length, and cadence) between the groups. In the sagittal rearfoot and sagittal midfoot coordination patterns, the flatfoot group showed a significantly greater proportion of anti-phase with proximal dominancy and a lower proportion of in-phase with proximal dominancy than the neutral foot group during early stance. Coordination variabilities between the sagittal rearfoot and sagittal midfoot (midstance), between the sagittal midfoot and sagittal forefoot (early stance), and between the frontal rearfoot and sagittal midfoot (midstance) were greater in the flatfoot group than in the neutral foot group. This may explain why those with flatfoot are likely to experience running injuries.

ISB recommendations for skin-marker-based multi-segment foot kinematics

The foot is anatomically and functionally complex, and thus an accurate description of intrinsic kinematics for clinical or sports applications requires multiple segments. This has led to the development of many multi-segment foot models for both kinematic and kinetic analyses. These models differ in the number of segments analyzed, bony landmarks identified, required marker set, defined anatomical axes and frames, the convention used to calculate joint rotations and the determination of neutral positions or other offsets from neutral. Many of these models lack validation. The terminology used is inconsistent and frequently confusing. Biomechanical and clinical studies using these models should use established references and describe how results are obtained and reported. The International Society of Biomechanics has previously published proposals for standards regarding kinematic and kinetic measurements in biomechanical research, and in this paper also addresses multi-segment foot kinematics modeling. The scope of this work is not to prescribe a particular set of standard definitions to be used in all applications, but rather to recommend a set of standards for collecting, calculating and reporting relevant data. The present paper includes recommendations for the overall modeling and grouping of the foot bones, for defining landmarks and other anatomical references, for addressing the many experimental issues in motion data collection, for analysing and reporting relevant results and finally for designing clinical and biomechanical studies in large populations by selecting the most suitable protocol for the specific application. These recommendations should also be applied when writing manuscripts and abstracts.

Differences in rearfoot, midfoot, and forefoot kinematics of normal foot and flatfoot during running

Flatfoot is a common foot deformity, which could contribute to running injuries such as medial tibial stress syndrome. Intrafoot kinematics of flatfoot during walking have often been documented using multisegment foot models. However, the intrafoot kinematics of flatfoot during running remains unclear, despite the possible relationship between flatfoot and running injuries. We aimed to clarify rearfoot, midfoot, and forefoot kinematics when running in participants with normal foot and flatfoot. Participants with the normal foot (n = 14) and flatfoot (n = 14) were asked to runover-ground at their preferred speed. Three-dimensional kinematics of the rearfoot, midfoot, and forefoot during running were calculated based on the Rizzoli foot model. A two-sample t-test of statistical parametric mapping was performed to determine differences between normal foot and flatfoot in time histories of intrafoot kinematics during running. No differences were found between groups in characteristics and spatiotemporal parameters. In the frontal rearfoot angle, a significantly increased eversion from 24% to 100% (p < .001) was observed in the flatfoot compared to the normal foot. At the midfoot angle, a significantly increased eversion from 0% to 4% (p < .049) and 21% to 100% (p < .001) was observed in the flatfoot compared to the normal foot. At the forefoot angle, a significantly increased inversion from 6% to 17% (p < .047) was observed in the flatfoot compared to the normal foot. These findings may be useful to explain why flatfoot could contribute to running injuries such as medial tibial stress syndrome.

Reliability of a close-range photogrammetry technique to measure ankle kinematics during active range of motion in place

BACKGROUND

As the risk of ankle turn during daily activity is very high, studying ankle kinematics in place is important for ankle sprain prevention. The close-range photogrammetry (CRP) technique is used to measure ankle kinematics during active range of motion (AROM) in place. The purpose of the study was to assess the reliability of CRP to measure ankle kinematics.

METHODS

Twenty adults were recruited and fourteen retro-reflective targets were mounted on the skin of their right feet. Imaging sensors were self-calibrated using a bundle adjustment technique, and the images were downloaded with Australis photogrammetric software. Three trials were conducted and reliability coefficients were used to assess agreement between them.

RESULTS

Reliability was almost perfect and the results show that the intraclass correlation coefficient (ICC) of ankle angle values were (dorsiflexion = 0.96), (plantarflexion = 0.81), (inversion = 0.92), (eversion = 0.95), (internal rotation = 0.92), and (external rotation = 0.78). The overall intraclass correlation coefficient was 0.89 and the standard error of the measurement (SEM) values ranged from (0.37° to 6.18°).

CONCLUSIONS

The results indicate that the CRP technique was able to reliably measure ankle kinematics. The results may support and enhance knowledge related to ankle AROM in the clinical arena.

Shank and rearfoot coordination and its variability during running in flatfoot

Flatfoot is a risk factor for patellofemoral pain syndrome (PFPS), and excessive rearfoot eversion occurring in flatfoot has been associated with the development and progression of PFPS; however, the mechanism remains unclear. This study aimed to investigate transverse shank and frontal rearfoot coordination patterns and variability when running with normal foot and flatfoot. Participants with normal foot (n = 13) and flatfoot (n = 13) were asked to run at their preferred speed. The coupling angle between the shank and rearfoot, representing intersegmental coordination, was calculated using the modified vector coding technique and categorized into four coordination patterns. Standard deviation of the coupling angle was computed as a measure of coordination variability during the stance phase. No differences in the characteristics and spatiotemporal parameters between groups were found, and all participants had rearfoot strike pattern. During midstance, the flatfoot group showed a significantly greater proportion of anti-phase with proximal (shank) dominancy than the normal foot group (p = 0.04, effect size = 0.88 [large]). Furthermore, flatfoot group showed a significantly greater in variability than the normal foot group (p = 0.03, effect size = 0.91 [large]). This study's results may help explain why flatfoot is likely to result in PFPS. However, the occurrence mechanism of running injuries like PFPS is multi- factorial. Since these results alone are not sufficient to explain the cause-effect relationship between flatfoot and injuries like PFPS, a prospective study including other factors such as patellofemoral joint stress would also be needed.

The biomechanical effects of pronated foot function on gait. An experimental study

The relationship between foot kinematics and the development of lower extremity musculoskeletal disorders (MSD) has been the focus of recent attention. However, most studies evaluated static foot type and not dynamic foot function. The purpose was to compare lower limb and foot kinematics, and plantar pressures during gait in physically active individuals with pronated and non-pronated foot function. Foot function in 154 adult participants was documented as pronated (n = 63) or neutral (n = 91) using 2 established methods: The Foot Posture Index and the Center of Pressure Excursion Index. Difference between the groups in triplanar motion of the lower limb during barefoot gait was evaluated using a 3D motion capture system incorporating the Oxford Foot Model. Dynamic parameters of plantar pressure were recorded using a pressure platform. Anterior-posterior pelvic tilt range of motion (ROM), peak knee internal rotation, forefoot dorsiflexion ROM, peak forefoot abduction, and rearfoot eversion were all increased in those with pronated foot function. Hallux contact time and time to peak force under the medial forefoot were increased with pronated foot function, and maximal force under the lateral forefoot was reduced. Pronated foot function affected the whole lower limb kinematic chain during gait. These kinematic alterations could increase the risk of developing MSD. Further studies should elucidate the relationship between pronated foot function and MSD, and, if confirmed, foot function should be evaluated in clinical practice for patients with lower limb and low back pain.

A comparison of the free moment pattern between normal and hyper-pronated aligned feet in female subjects during the stance phase of gait

BACKGROUND

Excessive range of adductory free moment of the ground reaction force may potentially increase the risk of lower extremity injuries by applying a higher torsional load transmitted to the proximal parts.

OBJECTIVE

It was hypothesized that the free moment pattern might be different between hyper-pronated and normal feet subjects. Moreover, a correlation would exist between peak adduction free moment and peak ankle-foot complex abduction at the stance phase of walking.

MATERIAL AND METHODS

In this cross sectional study, thirty female participants were divided into two groups of asymptomatic hyper-pronated and normal feet. Kinetic and kinematic data were collected using a single force plate and a six-camera motion analysis system during three successful free speed walking trials. Ensemble average curves were extracted from the time normalized individual trials of the stance phase for both free moment and peak ankle-foot complex abduction parameters.

RESULTS

Significant differences in peak adductory free moment, peak ankle-foot complex eversion and peak ankle-foot complex abduction were found between normal and hyper-pronated groups (4.90±0.97 Vs. 5.94±0.88, P < 0.01), (3.30±0.95 Vs. 6.28±1.47, P < 0.01) and (4.52±1.16 Vs. 8.23±2.52, P < 0.01) respectively. A significant positive correlation was found between the peak adduction free moment and peak ankle-foot complex abduction in both groups, which was more strongly positive in hyper-pronated group (r = 0.745, p < 0.01 for normal group and r = 0.900, p < 0.01 for hyper-pronated group).

CONCLUSION

As a good measure of torque which is transmitted to the lower extremity, may free moment be a useful biomechanical indicator for both clinical and research purposes.

Multisegment Foot Models and Clinical Application After Foot and Ankle Trauma: A Review

Since the end of the 1990s, several multisegment foot models (MSFMs) have been developed. Several models were used to describe foot and ankle kinematics in patients with foot and ankle pathologies; however, the diagnostic value for clinical practice of these models is not known. This review searched in the literature for studies describing kinematics in patients after foot and ankle trauma using an MSFM. The diagnostic value of the MSFMs in patients after foot and ankle trauma was also investigated. A search was performed on the databases PubMed/MEDLINE, Embase, and Cochrane Library. To investigate the diagnostic value of MSFMs in patients after foot and ankle trauma, studies were classified and analyzed following the diagnostic research questions formulated by Knottnerus and Buntinx. This review was based on 7 articles. All studies were published between 2010 and 2015. Five studies were retrospective studies, and 2 used an intervention. Three studies described foot and ankle kinematics in patients after fractures. Four studies described foot and ankle kinematics in patients after ankle sprain. In all included studies, altered foot and ankle kinematics were found compared with healthy subjects. No results on patient outcome using MSFMs and costs were found. Seven studies were found reporting foot and ankle kinematics in patients after foot and ankle trauma using an MSFM. Results show altered kinematics compared with healthy subjects, which cannot be seen by other diagnostic tests and add valuable data to the present literature; therefore, MSFMs seem to be promising diagnostic tools for evaluating foot and ankle kinematics. More research is needed to find the additional value for MSFMs regarding patient outcome and costs.

Sagittal subtalar and talocrural joint assessment between barefoot and shod walking: A fluoroscopic study

BACKGROUND

While wearing shoes is common in daily activities, most foot kinematic models report results on barefoot conditions. It is difficult to describe foot position inside shoes. This study used fluoroscopic images to determine talocrural and subtalar motion.

RESEARCH QUESTION

What are the differences in sagittal talocrual and subtalar kinematics between walking barefoot and while wearing athletic walking shoes?

METHODS

Thirteen male subjects (mean age 22.9 ± 2.9 years, mean weight 77.2 ± 6.9 kg, mean height 178.2 ± 3.7 cm) screened for normal gait were tested. A fluoroscopy unit was used to collect images during stance. Sagittal motion of the talocrural and subtalar joints of the right foot were analyzed barefoot and in an athletic walking shoe.

RESULTS

Shod talocrural position at heel strike was 6.0° of dorsiflexion and shod peak talocrural plantarflexion was 4.2°. Barefoot talocrural plantarflexion at heel strike was 4.2° and barefoot peak talocrural plantarflexion was 10.9°. Shod subtalar position at heel strike was 2.6° of plantarflexion and peak subtalar dorsiflexion was 1.5°. The barefoot subtalar joint at heel strike was in 0.4° dorsiflexion and barefoot peak subtalar dorsiflexion was 3.5°. As the result of wearing shoes, average walking speed and stride length increased and average cadence decreased. Comparing barefoot to shod walking there was a statistical significance in talocrural dorsiflexion and at heel strike and peak talocrural dorsiflexion, subtalar plantarflexion at heel strike and peak subtalar dorsiflexion, walking speed, stride length, and cadence.

SIGNIFICANCE

This work demonstrates the ability to directly measure talocrural and subtalar kinematics of shod walking using fluoroscopy. Future work using this methodology can be used to increase understanding of hindfoot kinematics during a variety of non-barefoot activities.

Multi-segment foot models and their use in clinical populations

BACKGROUND

Many multi-segment foot models based on skin-markers have been proposed for in-vivo kinematic analysis of foot joints. It remains unclear whether these models have developed far enough to be useful in clinical populations. The present paper aims at reviewing these models, by discussing major methodological issues, and analyzing relevant clinical applications.

RESEARCH QUESTION

Can multi-segment foot models be used in clinical populations?

METHODS

Pubmed and Google Scholar were used as the main search engines to perform an extensive literature search of papers reporting definition, validation or application studies of multi-segment foot models. The search keywords were the following: 'multisegment'; 'foot'; 'model'; 'kinematics', 'joints' and 'gait'.

RESULTS

More than 100 papers published between 1991 and 2018 were identified and included in the review. These studies either described a technique or reported a clinical application of one of nearly 40 models which differed according to the number of segments, bony landmarks, marker set, definition of anatomical frames, and convention for calculation of joint rotations. Only a few of these models have undergone robust validation studies. Clinical application papers divided by type of assessment revealed that the large majority of studies were a cross-sectional comparison of a pathological group to a control population.

SIGNIFICANCE

This review suggests that there is sufficient evidence that multi-segment foot models may be successfully applied in clinical populations. Analysis of the currently available models allows users to better identify the most suitable protocol for specific clinical applications. However new models require thorough validation and assessment before being used to support clinical decisions.

Kinematics reduction applied to the comparison of highly-pronated, normal and highly-supinated feet during walking

BACKGROUND

Kinematic analysis could help to study how variations in the static foot posture affect lower limb biomechanical function. The analysis of foot kinematics is complex because it involves managing the time-dependent joint angles in different joints and in all three planes of motion. But it could be simplified if joint angles are coordinated.

METHODS

The kinematics of the ankle, midtarsal and metatarsophalangeal joints were registered in 20 highly-pronated, 30 normal and 20 highly-supinated subjects (assessed by the Foot Posture Index - FPI) as they walked barefoot. Coordination for each sample was analysed through principal component analysis applied to the dorsiflexion, abduction and inversion angles measured. Finally, a systematic comparison among the samples was performed through a set of ANOVAs applied to the reduced variables corresponding to the factors found.

RESULTS

Three principal components (coordination patterns) accounted for about 70% of the variance of the joint angles, and were affected by the FPI. The main coordination in normal feet was the supination movement, while in highly-supinated and highly-pronated feet it was the flexion coordination of all foot joints, which could work against adaptation in cases of varying terrain. The original joint angles were reduced to three factors, and the ANOVAs applied to them showed that highly-pronated feet presented a delayed propulsion peak and smaller ranges of motion during propulsion regarding all factors, and that highly-supinated feet require more pronation time to fully support the foot during walking.

SIGNIFICANCE

The coordination patterns of normal feet might be considered the normal patterns used for an efficient gait, and may help in planning surgical procedures and designing foot prostheses or orthotics. Dimensional reduction makes it possible to perform more systematic kinematic analyses, which have revealed that highly-pronated feet are in poorer propulsive condition, and this in turn may make them more prone to injury.

The Influence of Plantar Short Foot Muscle Exercises on the Lower Extremity Muscle Strength and Power in Proximal Segments of the Kinematic Chain in Long-Distance Runners

The aim of this study was to evaluate the influence of plantar short foot muscles exercises on the performance of lower extremities in long-distance runners. 47 long-distance runners aged 21-45 years took part in this study. The participants were divided into two groups based on baseline measurement of Foot Posture Index: Group 1 (n=27) with neutral foot and Group 2 (n=20) with slight and increased pronation. The participants performed the exercises daily for 6 weeks. The knee flexors and extensors torque, work, and power on Isokinetic Dynamometer and Running-Based Anaerobic Sprint Test (RAST) were checked at baseline and after 6 weeks of exercises. Higher values of peak torque of knee flexors were observed. This change was statistically significant at high load with angular velocity 90°/s (73.55 Nm at baseline and 89.05 Nm after 6 weeks) and 160°/s (69.40 Nm at baseline and 79.00 Nm after 6 weeks) in Group 2. In both groups higher values of maximum power were noted. Participants in Group 2 achieved lower values in each 35-metre run time and higher values of power. In Group 2 there was significant improvement of total time (35.26 s at baseline and 34.79 s after 6 weeks) compared to Group 1 (37.33 s at baseline and 37.56 s after 6 weeks). Exercises strengthening short foot muscles may improve energy transfer through body segments and increase strength and values of generated power. They should be included as a part of daily training programme of runners. This study was registered in the Australian New Zealand Clinical Trials Registry (ANZCTR). Registration number: ACTRN12615001200572.

Kinematic differences between neutral and flat feet with and without symptoms as measured by the Oxford foot model

BACKGROUND

Flatfoot is a common presentation in children. It is usually asymptomatic, though a small number of children experience pain. Foot function during flatfoot walking is rarely considered, yet as an activity that places significant demands on the feet, this could explain the differences in terms of symptoms.

RESEARCH QUESTION

This paper investigates walking patterns in neutral and flat feet, with and without symptoms, to determine which kinematic parameters are associated with symptomatic flat feet.

METHODS

This is a retrospective study in which one hundred and six children between five and 18 years old were assessed by a physiotherapist for foot posture. Each foot was classified into one of four groups, giving 98 asymptomatic neutral, 47 asymptomatic mild flat, 29 asymptomatic flat, and 38 symptomatic flat feet with complete data for analysis. Using Plug-In-Gait and Oxford-Foot-Model markers, walking kinematics were measured, along with ground reaction forces. Median values of 14 lower limb joint angles were calculated at foot strike, midstance, and foot off. Each foot was treated as an independent sample. ANOVA and ANCOVA (with the speed-related variable relative stride length as the covariate) and post-hoc tests were used to assess whether angles differed between groups.

RESULTS

The symptomatic flat feet showed significant differences from asymptomatic groups (most commonly the neutral feet) in terms of hip flexion, knee flexion and varus, hindfoot inversion-eversion, and forefoot abduction-adduction. Increased forefoot abduction occurred throughout stance phase in symptomatic flatfooted participants compared to all asymptomatic groups.

SIGNIFICANCE

The results suggest that foot motion in the transverse plane is closely associated with the presence of symptoms in flat feet and that this is accompanied by changes in the kinematics of the ankle, knee, and hip.

Effect of static foot posture on the dynamic stiffness of foot joints during walking

BACKGROUND

The static foot posture has been related to the development of lower limb injuries.

RESEARCH QUESTION

This study aimed to investigate the dynamic stiffness of foot joints during gait in the sagittal plane to understand the role of the static foot posture in the development of injuries.

METHODS

Seventy healthy adult male subjects with different static postures, assessed by the Foot Posture Index (FPI) (30 normal, 20 highly pronated and 20 highly supinated), were recruited. Kinematic and kinetic data were recorded using an optical motion capture system and a pressure platform, and dynamic stiffness at the different stages of the stance was calculated from the slopes of the linear regression on the flexion moment-angle curves. The effect of foot type on dynamic stiffness and on ranges of motion and moments was analysed using ANOVAs and post-hoc tests, and linear correlation between dynamic stiffness and FPI was also tested.

RESULTS

Highly pronated feet showed a significantly smaller range of motion at the ankle and metatarsophalangeal joints and also a larger range of moments at the metatarsophalangeal joint than highly supinated feet. Dynamic stiffness during propulsion was significantly greater at all foot joints for highly pronated feet, with positive significant correlations with the squared FPI. Highly supinated feet showed greater dynamic stiffness than normal feet, although to a lesser extent. Highly pronated feet during normal gait experienced the greatest decrease in the dorsiflexor moments during propulsion, normal feet being the most balanced regarding work generated and absorbed.

SIGNIFICANCE

Extreme static foot postures show greater dynamic stiffness during propulsion and greater absorbed work, which increases the risk of developing injuries. The data presented may be used when designing orthotics or prostheses, and also when planning surgery that modifies joint stiffness.

Foot and Ankle Kinematics During Descent From Varying Step Heights

In the general population, one-third of incidences during step negotiation occur during the transition to level walking. Furthermore, falls during curb negotiation are a common cause of injury in older adults. Distal foot kinematics may be an important factor in determining injury risk associated with transition step negotiation. The purpose of this study was to identify foot and ankle kinematics of uninjured individuals during descent from varying step heights. A 7-segment foot model was used to quantify kinematics as participants walked on a level walkway, stepped down a single step (heights: 5 cm, 15 cm, 25 cm), and continued walking. As step height increased, landing strategy transitioned from the rearfoot to the forefoot, and the rearfoot, lateral and medial midfoot, and medial forefoot became more plantar flexed. During weight acceptance, sagittal plane range of motion of the rearfoot, lateral midfoot, and medial and lateral forefoot increased as step height increased. The changes in landing strategy and distal foot function suggest a less stable ankle position at initial contact and increased demand on the distal foot at initial contact and through the weight acceptance phase of transition step negotiation as step height increases.

Effect of total-contact orthosis on medial longitudinal arch and lower extremities in flexible flatfoot subjects during walking

BACKGROUND

Total-contact orthosis (TCO) is one kind of foot orthosis (FO) that is used to adjust biomechanics in flexible flatfoot.

OBJECTIVE

To determine the effects of a TCO on the MLA moment, MLA deformation angle and lower limb biomechanics.

STUDY DESIGN

Cross-sectional study.

METHODS

Seven-flatfoot and thirteen-normal foot subjects were recruited by footprint and radiographs. The biomechanics of subjects with normal foot (NF), flatfoot with shoe only (FWOT) and flatfoot with TCO (FWT) were collected in a 3D motion analysis laboratory and force plates. The MLA and lower limb biomechanics in each condition during specific sub-phases of stance were analyzed.

RESULTS

The NF had larger MLA eversion moment after shod walking ( p = 0.001). The FWT condition compared with the FWOT condition had a significantly larger peak MLA upward moment ( p = 0.035) during pre-swing, larger peak knee external rotation angle ( p = 0.040) during mid stance, smaller peak knee extension moment during terminal stance ( p = 0.035) and a larger ground reaction force in the anterior-posterior direction during early stance ( p < 0.05).

CONCLUSION

Our study found positive effects from the customized TCOs which included an increased TCO angle that led to a decreased peak MLA moment in the frontal plane in flexible flatfoot subjects during walking. Clinical relevance Lower limb biomechanics is different from normal in subjects with flexible flatfoot. The design of a TCO affects MLA, ankle and knee biomechanics and may be used to clinically correct biomechanical changes in flexible flatfoot.

Foot posture is associated with kinematics of the foot during gait: A comparison of normal, planus and cavus feet

Variations in foot posture are associated with the development of some lower limb injuries. However, the mechanisms underlying this relationship are unclear. The objective of this study was to compare foot kinematics between normal, pes cavus and pes planus foot posture groups using a multi-segment foot model. Ninety-seven healthy adults, aged 18-47 were classified as either normal (n=37), pes cavus (n=30) or pes planus (n=30) based on normative data for the Foot Posture Index, Arch Index and normalised navicular height. A five segment foot model was used to measure tri-planar motion of the rearfoot, midfoot, medial forefoot, lateral forefoot and hallux during barefoot walking at a self-selected speed. Angle at heel contact, peak angle, time to peak angle and range of motion was measured for each segment. One way ANOVAs with post-hoc analyses of mean differences were used to compare foot posture groups. The pes cavus group demonstrated a distinctive pattern of motion compared to the normal and pes planus foot posture groups. Effect sizes of significant mean differences were large and comparable to similar studies. Three key differences in overall foot function were observed between the groups: (i) altered frontal and transverse plane angles of the rearfoot in the pes cavus foot; (ii) Less midfoot motion in the pes cavus foot during initial contact and midstance; and (iii) reduced midfoot frontal plane ROM in the pes planus foot during pre-swing. These findings indicate that foot posture does influence motion of the foot.

Dynamic foot function as a risk factor for lower limb overuse injury: a systematic review

Background

Dynamic foot function is considered a risk factor for lower limb overuse injuries including Achilles tendinopathy, shin pain, patellofemoral pain and stress fractures. However, no single source has systematically appraised and summarised the literature to evaluate this proposed relationship. The aim of this systematic review was to investigate dynamic foot function as a risk factor for lower limb overuse injury.

Methods

A systematic search was performed using Medline, CINAHL, Embase and SportDiscus in April 2014 to identify prospective cohort studies that utilised dynamic methods of foot assessment. Included studies underwent methodological quality appraisal by two independent reviewers using an adapted version of the Epidemiological Appraisal Instrument (EAI). Effects were expressed as standardised mean differences (SMD) for continuous scaled data, and risk ratios (RR) for nominal scaled data.

Results

Twelve studies were included (total n = 3,773; EAI 0.44 to 1.20 out of 2.00, representing low to moderate quality). There was limited to very limited evidence for forefoot, midfoot and rearfoot plantar loading variables (SMD 0.47 to 0.85) and rearfoot kinematic variables (RR 2.67 to 3.43) as risk factors for patellofemoral pain; and plantar loading variables (forefoot, midfoot, rearfoot) as risk factors for Achilles tendinopathy (SMD 0.81 to 1.08). While there were significant findings from individual studies for plantar loading variables (SMD 0.3 to 0.84) and rearfoot kinematic variables (SMD 0.29 to 0.62) as risk factors for ‘non-specific lower limb overuse injuries’, these were often conflicting regarding different anatomical regions of the foot. Findings from three studies indicated no evidence that dynamic foot function is a risk factor for iliotibial band syndrome or lower limb stress fractures.

Conclusion

This systematic review identified very limited evidence that dynamic foot function during walking and running is a risk factor for patellofemoral pain, Achilles tendinopathy, and non-specific lower limb overuse injuries. It is unclear whether these risk factors can be identified clinically (without sophisticated equipment), or modified to prevent or manage these injuries. Future prospective cohort studies should address methodological limitations, avoid grouping different lower limb overuse injuries, and explore clinically meaningful representations of dynamic foot function.

Electronic supplementary material

The online version of this article (doi:10.1186/s13047-014-0053-6) contains supplementary material, which is available to authorized users.

The effects of low arched feet on foot rotation during gait in children with Down syndrome

BACKGROUND

In children with Down syndrome (DS) hypotonia and ligament laxity are characteristic features which cause a number of orthopaedic issues, such as flat foot. The aim of this study was to determine if children with flat foot are characterised by an accentuated external foot rotation during walking.

METHOD

Fifty-five children with DS and 15 typically developing children recruited as control group were assessed using three-dimensional gait analysis, using an optoelectronic system, force platforms and video recording. Parameters related to foot rotation were identified and calculated and the participants' foot morphology was assessed using the arch index.

RESULTS

Data obtained in this study showed that while DS children without flat foot displayed the foot position on the transverse plane globally close to controls during the whole gait cycle, the DS children with flat foot were characterised by higher extra-rotation of the foot in comparison with those without flat foot and controls.

CONCLUSIONS

Our results suggest that the presence of flatfoot lead the children with DS to extra-rotate their feet more than the children without flat foot. From a clinical point of view, these results could enhance the rehabilitative programmes in DS.

Reliability and relevance of radiographic measures of metatarsus primus elevatus and arch alignment in individuals with midfoot arthritis and controls

BACKGROUND

Low arch alignment and metatarsus primus elevatus (MPE) have been postulated to increase dorsal compressive stresses in the joints of the medial column of the foot and to contribute to the development of degenerative changes. The primary purposes of this study were (1) to examine the relationship between radiographic measures of arch alignment and MPE and (2) to assess arch alignment and MPE in individuals with midfoot arthritis and in asymptomatic controls. The secondary aim was to examine the reliability of radiographic measures of arch alignment and MPE.

METHODS

Radiographic measures of arch height and MPE were quantified on 28 individuals with midfoot arthritis and 22 individuals in a control group. Reliability was assessed using the intraclass correlation coefficient (ICC). The Pearson product moment correlation (r) was used to assess the relationship between arch alignment and MPE. Between-group differences were assessed using a two-sample t test (α = 0.05).

RESULTS

Good to excellent reliability was noted for measures of arch height (ICC[2,3] = 0.919-0.994) as well as MPE (ICC[2,3] = 0.891-0.882). A modest positive association was noted between normalized cortical elevation and normalized navicular height (r = 0.274, P = .030) and calcaneal inclination angle (r = 0.263, P = .035). Individuals with midfoot arthritis demonstrated lower arch alignment, reflected in a significantly higher calcaneal-first metatarsal angle (P = .002), lower calcaneal inclination angle (P = .004), and lower normalized navicular height (P < .001) compared with controls. No evidence was found to support between-group differences in lateral intermetatarsal angle (P = .495) and normalized cortical elevation (P = .146).

CONCLUSIONS

These findings provide objective data establishing the reliability of measures of MPE and arch alignment and their potential clinical significance.

A comparison of two multisegment foot models in high-and low-arched athletes

BACKGROUND

Malalignment and dysfunction of the foot have been associated with an increased propensity for overuse and traumatic injury in athletes. Several multisegment foot models have been developed to investigate motions in the foot. However, it remains unknown whether the kinematics measured by different multisegment foot models are equivocal. The purpose of the present study is to examine the efficacy of two multisegment foot models in tracking aberrant foot function.

METHODS

Ten high-arched and ten low-arched female athletes walked and ran while ground reaction forces and three-dimensional kinematics were tracked using the Leardini and Oxford multisegment foot models. Ground reaction forces and joint angles were calculated with Visual 3D (C-Motion Inc, Germantown, MD). Repeated-measures analyses of variance were used to analyze peak eversion, time to peak eversion, and eversion excursions.

RESULTS

The Leardini model was more sensitive to differences in peak eversion angles than the Oxford model. However, the Oxford model detected differences in eversion excursion values that the Leardini model did not detect.

CONCLUSIONS

Although both models found differences in frontal plane motion between high- and low-arched athletes, the Leardini multisegment foot model is suggested to be more appropriate as it directly tracks frontal plane midfoot motion during dynamic motion.

The relationship between foot posture and lower limb kinematics during walking: A systematic review

Variations in foot posture, such as pes planus (low-arched foot) or pes cavus (high-arched foot), are thought to be an intrinsic risk factor for injury due to altered motion of the lower extremity. Hence, the aim of this systematic review was to investigate the relationship between foot posture and lower limb kinematics during walking. A systematic database search of MEDLINE, CINAHL, SPORTDiscus, Embase and Inspec was undertaken in March 2012. Two independent reviewers applied predetermined inclusion criteria to selected articles for review and selected articles were assessed for quality. Articles were then grouped into two broad categories: (i) those comparing mean kinematic parameters between different foot postures, and (ii) those examining associations between foot posture and kinematics using correlation analysis. A final selection of 12 articles was reviewed. Meta-analysis was not conducted due to heterogeneity between studies. Selected articles primarily focused on comparing planus and normal foot postures. Five articles compared kinematic parameters between different foot postures - there was some evidence for increased motion in planus feet, but this was limited by small effect sizes. Seven articles investigated associations between foot posture and kinematics - there was evidence that increasing planus foot posture was positively associated with increased frontal plane motion of the rearfoot. The body of literature provides some evidence of a relationship between pes planus and increased lower limb motion during gait, however this was not conclusive due to heterogeneity between studies and small effect sizes.

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.

The effects of low arched feet on lower limb gait kinematics in children

BACKGROUND

The effects of foot posture on the dynamic function of the lower limb during gait remains relatively unknown.

OBJECTIVES

The purpose of this study was to investigate lower limb kinematics between the normal and low arched foot during the gait cycle, particularly in the transverse plane.

METHOD

Twenty-four children, twelve with normal and twelve with low arched feet, aged 11-12 years underwent a lower limb three dimensional gait analysis. Temporo-spatial parameters and patterns and ranges of motion of kinematic data were examined for the pelvis, hip, knee and ankle throughout the gait cycle.

RESULTS

Overall, there were very few differences found in the kinematics of the lower limbs between the normal and low arched group. Increased external hip rotation (6-7°) in the low arched group was the only bilateral significant difference (p<0.05) between the two foot groups. No significant differences existed in any temporo-spatial parameters between the two groups.

CONCLUSIONS

The increased external hip rotation and greater external foot progression angle in the low arched foot highlights the need to examine gait comprehensively to establish cause or effect of these differences observed and hence determine appropriate treatment.

Body of evidence supporting the clinical use of 3D multisegment foot models: a systematic review

BACKGROUND

A critical component in the characterization of foot mechanics during clinical gait analysis is the quantitative measurement of foot kinematics. Currently, the use of 3D multisegment foot models (3DMFMs) is popular in gait laboratories as it would seem to be an adequate tool for the in vivo analysis of dynamic foot kinematics. This systematic review identifies and evaluates current evidence for the use of 3DMFMs in clinical gait analysis.

METHODS

A targeted search strategy traced full papers that fulfilled the inclusion and exclusion criteria. The papers were classified and evaluated for quality using a custom made quality appraisal form.

FINDINGS

Forty-one manuscripts were included yielding a total number of fifteen 3DMFMs. Generally, study procedures and sample selection were adequately described; however, the methodological quality varied widely. Evidence regarding the repeatability of the identified models also varied widely. Models facing the highest level of scientific credibility were characterized by adequate repeatability indices obtained from between-trial, between-day and between and within assessor studies. Generally, the highest reliability indices were found for the sagittal plane kinematics. Within-subject variability was found to be the lowest, contrarily, between-subject and between-day variabilities were found to be highest.

INTERPRETATION

Reported repeatability indices such as the coefficient of multiple correlation, standard deviation and standard error of measurement provide evidence for the continued use of 3DMFMs. While a number of published models exist, there is no adequate evidence available to support their clinical use. More reliability and validity studies are needed to confirm adequate measurement properties of 3DMFMs.

A comparison of foot kinematics in people with normal- and flat-arched feet using the Oxford Foot Model

Foot posture is thought to influence predisposition to overuse injuries of the lower limb. Although the mechanisms underlying this proposed relationship are unclear, it is thought that altered foot kinematics may play a role. Therefore, this study was designed to investigate differences in foot motion between people with normal- and flat-arched feet using the Oxford Foot Model (OFM). Foot posture in 19 participants was documented as normal-arched (n=10) or flat-arched (n=9) using a foot screening protocol incorporating measurements from weightbearing antero-posterior and lateral foot radiographs. Differences between the groups in triplanar motion of the tibia, rearfoot and forefoot during walking were evaluated using a three-dimensional motion analysis system incorporating a multi-segment foot model (OFM). Participants with flat-arched feet demonstrated greater peak forefoot plantar-flexion (-13.7° ± 5.6° vs -6.5° ± 3.7°; p=0.004), forefoot abduction (-12.9° ± 6.9° vs -1.8° ± 6.3°; p=0.002), and rearfoot internal rotation (10.6° ± 7.5° vs -0.2°± 9.9°; p=0.018) compared to those with normal-arched feet. Additionally, participants with flat-arched feet demonstrated decreased peak forefoot adduction (-7.0° ± 9.2° vs 5.6° ± 7.3°; p=0.004) and a trend towards increased rearfoot eversion (-5.8° ± 4.4° vs -2.5° ± 2.6°; p=0.06). These findings support the notion that flat-arched feet have altered motion associated with greater pronation during gait; factors that may increase the risk of overuse injury.

A comparison of foot arch measurement reliability using both digital photography and calliper methods

Background

Both calliper devices and digital photographic methods have been used to quantify foot arch height parameters. The purpose of this study was to compare the reliability of both a calliper device and digital photographic method in determining the arch height index (AHI).

Methods

Twenty subjects underwent measurements of AHI on two separate days. On each day, AHI measurements during both sitting and standing were taken using the AHIMS and digital photographic methods by the same single tester. The intra-tester reliability of each measurement technique was assessed using intraclass correlation coefficients (ICC) and standard error of measurement (SEM). Additionally, the relationship between AHI measurements derived from the two different methods was assessed using a correlation analysis.

Results

The reliability for both the AHIMS and digital photographic methods was excellent with ICC values exceeding 0.86 and SEM values of less than 0.009 for the AHI. Moreover, the reliability of both measurement techniques was equivalent. There was a strong positive correlation between the AHI values collected using both methods. AHI values calculated using the digital photographic method tended to be greater than those derived using the AHIMS.

Conclusion

Digital photographic methods offer equivalent intra-tester reliability to previously established calliper methods when assessing AHI. While AHI measurements calculated using both methods were highly related, the greater AHI values in the photographic method implied caution should be exercised when comparing absolute values between the two methods. Future studies are required to determine whether digital photographic methods can be developed with improved validity.

The use of gait analysis in the treatment of pediatric foot and ankle disorders

Assessment of foot pathology during walking should form an integral part of the clinical evaluation of children. Simple observation and video recording have limitations and are not quantifiable. Three-dimensional analysis of foot motion during walking can provide invaluable information on the dynamic function of the foot and can contribute to clinical decision making. As motion analysis technology advances, the accuracy and reliability of the dynamic assessment of the foot during walking will increase further, allowing clinicians to rely confidently on this information during patient assessment and the study of treatment outcomes. It is logical to expect that objective and quantifiable assessment of gait should be undertaken before and after treatment that sets gait improvement as one of its aims.