Prevalence of Flexible Flat Foot in Adults: A Cross-sectional Study

Higher revision rates in patients with preoperative contralateral pes planovalgus deformity following total knee arthroplasty

PURPOSE

The purpose of this study was to compare the incidence of revision in those with pes planovalgus deformity to those without using a large national database. Given the reciprocal changes in lower extremity alignment associated with planovalgus foot deformity, it has been suggested that patients with this deformity has worse outcomes following total knee arthroplasty (TKA).

METHODS

A retrospective cohort analysis of patients undergoing elective TKA was conducted using the PearlDiver database. Patients were stratified into three cohorts: those without pes planovalgus, patients with ipsilateral or bilateral pes planovalgus relative to the TKA, and patients with contralateral pes planovalgus. Patients with prior foot reconstructive surgery were excluded. The cohorts were each matched to those without pes planovalgus. Bivariate analysis was performed comparing 90-day medical complications and 2- and 4-year revisions following TKA. An adjusted number needed to be exposed for one additional person to be harmed (NNEH) was calculated using the adjusted odds ratio (OR) and unexposed event rate.

RESULTS

Following matched analysis, those with contralateral pes planovalgus had similar odds (OR 3.41; 95% CI 0.93-12.54; p = n.s.) for aseptic revision within 2 years but significantly higher odds (OR 3.35; 95% CI 1.08-10.41; p = 0.03) within 4 years when compared to those without a pes planovalgus deformity. Within 4 years, there was no significant difference in the incidence of aseptic revision (p = n.s.) in patients with ipsilateral/bilateral pes planovalgus. No patients in any cohort underwent septic revision within 4 years of TKA.

CONCLUSION

This study found that patients with contralateral pes planovalgus deformity had higher odds of aseptic revision within 4 years following primary TKA in a national database, suggesting that the change in gait kinematics associated with this deformity could possibly be associated with increased revision rates.

LEVEL OF EVIDENCE

Level III.

Pediatric and Adolescent Flatfoot: A Questionnaire Based Middle East and North Africa Study

Background

Flatfoot is commonly seen in the community and is a common cause of concern for parents because it could become symptomatic and lead to decreased quality of life. One of the most used management approaches is foot orthoses, although no clear evidence supports their use. We aimed to study flatfoot symptoms' prevalence, effect on activities of daily living, and the use and effectiveness of orthoses.

Methodology

This was a cross-sectional study that included five countries from the Middle East and North Africa region (Jordan, Palestine, Syria, Egypt, and Iraq). Data were collected using an online questionnaire directed toward parents of children aged 0 to 16 from September to December 2020. The demographic factors were expressed as frequencies (percentages) using standard descriptive statistical parameters, and Pearson's chi-square test was used to examine the relationship between study factors.

Results

1256 participants were recruited using this online survey. The majority (29.6%) of children were diagnosed in the age group of 0 to 2. The abnormal appearance of the foot was the most common (78.7%) complaint. Overall, 54.2% of patients were prescribed orthoses, of which 36.8% noticed improvement in flatness and 37.6% reported relief of symptoms.

Conclusion

This study demonstrated that most participants have no or minimal symptoms and that there is a mismatch between participants' expectations and the actual effectiveness of orthoses. Taking into consideration that there is no clear evidence to support the corrective effect of orthoses, we recommend that physicians prescribing them adhere more to their proper indications and spend more time and effort counseling and addressing patients' and parents' concerns about this developmental stage.

Gluteus medius muscle strengthening exercise effects on medial longitudinal arch height in individuals with flexible flatfoot: a randomized controlled trial

This study aimed to compare the effects of 8 weeks of foot plus hip exercise to foot exercise alone on medial longitudinal arch (MLA) parameters; navicular drop (ND), arch height index (AHI), plantar pressure, static balance, and dynamic balance were measured at baseline, 4 weeks, and 8 weeks. A total of 52 healthy participants with bilateral flatfoot were randomly assigned into foot exercise (n=26) and foot plus hip exercise (n=26) group. At 4 weeks, the foot plus hip exercise group showed significantly less ND (P=0.002), plantar pressure at the medial forefoot (P=0.002), and mediolateral displacement (P=0.001) while showing a greater AHI (P=0.019) than the foot exercise group. At 8 weeks, there was also significantly less plantar pressure at the medial hindfoot (P=0.017) and less anteroposterior displacement (P=0.002) in the foot plus hip exercise group than in the foot exercise group. No significant differences between groups were found in dynamic balance. The addition of gluteus medius muscle strengthening exercise to foot exercise was more effective in supporting the MLA than performing foot exercise alone.

Achilles Tendon, Patellar Tendon, and Femoral Cartilage Thickness in Control vs Asymptomatic Flatfoot Young Adults

BACKGROUND

Changes in lower extremity alignment in individuals with flatfoot may be associated with differences in morphology of the tendons or cartilage in lower extremities. The purpose of the present study was to investigate the potential association of flatfoot with the morphology of the Achilles tendon, patellar tendon, and femoral cartilage.

METHODS

This study was conducted with 40 participants with flatfoot (28 females, 12 males) and 40 participants with a normal foot posture (28 females, 12 males). The thickness of the Achilles tendon (at points 2 and 3 cm proximal to the superior aspect of the calcaneus), patellar tendon (at the inferior pole of the patella and 1 cm proximal of the inferior pole of the patella), and femoral cartilage (at the intercondylar area, medial condyle, and lateral condyle) was measured by an ultrasonography device.

RESULTS

The Achilles tendon thickness at 2 cm (P = .009) and 3 cm (P = .010) proximal of the superior aspect of the calcaneus was on average 4% to 6% lower in individuals with flatfoot compared with controls. The cartilage thickness at the intercondylar area (P = .005) and medial condyle (P = .018) was on average 8% to 12% greater in individuals with flatfoot; however, the cartilage thickness at the lateral condyle and patellar tendon thickness was similar in both groups.

CONCLUSION

The results obtained suggest that foot posture is associated with the morphology of the Achilles tendon and femoral cartilage.

LEVEL OF EVIDENCE

Level III, diagnostic comparative study.

Low-dye taping may enhance physical performance and muscle activation in basketball players with overpronated feet

BACKGROUND

Low-dye taping (LTD) is widely used by athletes and medical practitioners but the research regarding its impacts on athletic performance is lacking. This study investigated the effects of using low-dye taping on plyometric performance and muscle activities in recreational basketball players with overpronated feet.

METHODS

Twelve collegiate males with at least three years basketball training experience and navicular drop (ND) value ≥10 mm performed the navicular drop, drop jump and countermovement jump tests. Surface electromyography of selected lower limb muscles were observed during bilateral free squat. All tests in non-taped (NT) and taped (TAP) conditions were counterbalanced using repeated crossover study design. Paired t-test with an alpha level of 0.05 and non-clinical magnitude-based decision (MBD) with standardized effects were used to analyze data.

RESULTS

Contact time and reactive strength index (RSI) in the TAP condition were significantly shorter (p = 0.041) and higher (p<0.01) than the NT condition respectively. No significant difference in CMJ performance between NT and TAP was observed. MBD demonstrated clear effects on both ND (standardized effect: -1.54±0.24), flight time (standardized effect: 0.24±0.30), contact time (standardized effect: -0.27±0.21), RSI (standardized effect: 0.69±0.35) and eccentric activities of inferior gluteus maximus (standardized effect: 0.23±0.35), gluteus medius (standardized effect: 0.26±0.29) and tibialis anterior (standardized effect: 0.22±0.06).

CONCLUSIONS

LDT is effective in correcting overpronated feet by increasing ND height. Meanwhile, it provides a small increase in RSI and gluteal muscle activity during the eccentric (down) phase of the bilateral squat, and without affecting CMJ performance. Conditioning coaches or therapists may use LDT to enhance gluteal activation for reducing injury occurrence and reactive strength performance in drop jump tasks.

Diagnostic Accuracy of Various Radiological Measurements in the Evaluation and Differentiation of Flatfoot: A Cross-Sectional Study

Arch angle is used to indicate flatfoot, but in some cases, it is not easily defined. The presence of flatfoot deformity remains difficult to diagnose due to a lack of reliable radiographic assessment tools. Although various assessment methods for flatfoot have been proposed, there is insufficient evidence to prove the diagnostic accuracy of the various tools. The main purpose of the study was to determine the best radiographic measures for flatfoot concerning the arch angle. Fifty-two feet radiographs from thirty-two healthy young females were obtained. Five angles and one index were measured using weight-bearing lateral radiographs; including arch angle, calcaneal pitch (CP), talar-first metatarsal angle (TFM), lateral talar angle (LTA), talar inclination angle (TIA) and navicular index (NI). Receiver-operating characteristics were generated to evaluate the flatfoot diagnostic accuracy for all radiographic indicators and Matthews correlation coefficient was calculated to determine the cutoff value for each measure. The strongest correlation was between arch angle and CP angle [r = −0.91, p ≤ 0.0001, 95% confidence interval (CI) (from −0.94 to −0.84)]. Also, significant correlations were found between arch angle and NI [r = 0.62, p ≤ 0.0001, 95% CI (0.42 to 0.76)], and TFM [r = 0.50, p ≤ 0.0001, 95% CI (from 0.266 to 0.68)]. Furthermore, CP (cutoff, 12.40) had the highest accuracy level with value of 100% sensitivity and specificity followed by NI, having 82% sensitivity and 89% specificity for the cutoff value of 9.90. In conclusion, CP angle is inversely correlated with arch angle and considered a significant indicator of flatfoot. Also, the NI is easy to define radiographically and could be used to differentiate flat from normal arched foot among young adults.

Examining the Relationship between Pes Planus Degree, Balance and Jump Performances in Athletes

The foot absorbs shocks with its arches, muscles, ligaments and joints, and bodyweight transmission and it pushes the body forward during all movement patterns. Pes planus is more important in sports activities that include balance and sports performance, such as walking, running, jumping, or transferring weight to a single lower limb. This study, conducted with this information in mind, aims to examine the effects of pes planus deformity on balance and vertical jump performance. Fifty athletes were included in the study. The presence of pes planus was evaluated according to the Feiss line. Balance measurements were performed with a Balance System SD Biodex. Vertical jump performance was recorded using an Omegawave jumping mat. The relationship between the pes planus grades of the participants and their balance and jump performances was analyzed using the Spearman correlation method. Vertical jump and Limit of stability (LOS) was significantly correlated with pes planus.

Analysis of skeletal characteristics of flat feet using three-dimensional foot scanner and digital footprint

Background

Flat feet increase the risk of knee osteoarthritis and contribute to frailty, which may lead to worse life prognoses. The influence of the foot skeletal structure on flat feet is not yet entirely understood. Footprints are often used to evaluate feet. However, footprint-based measurements do not reflect the underlying structures of feet and are easily confounded by soft tissue. Three-dimensional evaluation of the foot shape can reveal the characteristics of flat feet. Therefore, foot shape evaluations have garnered increasing research interest. This study aimed to determine the correlation between the three-dimensional (3D) features of the foot and the measurement results of footprint and to predict the evaluation results of flat feet from the footprint based on the 3D features. Finally, the three-dimensional characteristics of flat feet, which cannot be revealed by footprint, were determined.

Methods

A total of 403 individuals (40–89 years) participated in this study. The proposed system was developed to identify seven skeletal features that were expected to be associated with flat feet. The loads on the soles of the feet were measured in a static standing position and with a digital footprint device. Specifically, two footprint indices were calculated: the Chippaux–Smirak index (CSI) and the Staheli index (SI). In the analysis, comparisons between male and female measurement variables were performed using the Student’s t test. The relationships between the 3D foot features and footprint index parameters were determined by employing the Pearson correlation coefficient. Multiple linear regression was utilized to identify 3D foot features that were strongly associated with the CSI and SI. Foot features identified as significant in the multivariate regression analysis were compared based on a one-way analysis of variance (ANOVA) with Tukey’s post hoc test.

Results

The CSI and SI were highly correlated with the instep height (IH) and navicular height (NH) of the 3D foot scanning system and were also derived from multiple regression analysis. In addition to the NH and IH, the indicators of the forefoot, transverse arch width, and transverse arch height were considered. In the flat foot group with CSI values above 62.7%, NH was 13.5% (p < 0.001) for males and 14.9% (p = 0.01) for females, and the axis of the bone distance was 5.3% (p = 0.05) for males and 4.9% (p = 0.10) for females. In particular, for CSI values above 62.7% and NH values below 13%, the axis of the bone distance was large and the foot skeleton was deformed.

Conclusions

Decreased navicular bone height could be evaluated with the 3D foot scanning system even when flat feet were not detected from the footprint. The results indicate that the use of quantitative indices for 3D foot measurements is important when evaluating the flattening of the foot.

Trial registration number UMIN000037694.

Name of the registry: University Hospital Medical Information Network Registry.

Date of registration: August 15, 2019.

Strength, Flexibility and Postural Control of the Trunk and Lower Body in Participants with and without Patellofemoral Pain

Patellofemoral pain (PFP) is a frequent knee condition. The aim of this study was to investigate strength, flexibility and postural control in people with and without PFP. Fifty-five participants between 14 and 54 years of age (PFP = 18, control group = 37) were included. Strength and flexibility for all trunk, hip, knee and ankle muscle groups were measured along with postural control outcomes. Analyses were conducted based on the “affected” and “non-affected” leg within-group and between-groups. Between-groups analysis demonstrated a statistically lower strength of trunk muscles (range: 35.8–29.3%, p < 0.001), knee extensors (20.8%, p = 0.005) and knee flexors (17.4%, p = 0.020) in PFP participants. Within-group analysis proved an 8.7% (p = 0.018) greater hip internal rotation strength and ankle extension flexibility (p = 0.032) of the “affected side” in PFP participants. This was, to our knowledge, the first study to investigate the strength of all trunk muscle groups. The results indicate that participants with PFP exhibit impaired strength of trunk muscle groups, along with knee muscle deficits, which may present a rehabilitation target. Clinicians should consider implementing trunk strengthening exercises into PFP programs along with knee-targeting exercise programs.

Effects of a 6-Minute Fast-Walking Protocol on Changes in Muscle Activity in Individuals with Flatfoot

Flatfoot causes abnormal biomechanics in the lower extremity, resulting in discomfort and excessive burden on lower extremity muscles during functional tasks, and it potentially leads to associated syndromes in the lower extremity. The aim of this study was to investigate how a demanding, repetitive task affects the muscle strength, activities, and fatigue of the lower extremities during function tasks. Nineteen individuals with flexible flatfoot (10M9F, age: 24.74 ± 2.68 years) and fifteen non-flatfoot participants (6M9F, age: 24.47 ± 3.74) took part in this study. All participants performed maximal voluntary isometric contraction and functional tasks, including walking and single-leg standing tests before and immediately after a 6-min fast-walking protocol. A surface electromyography system was used to collect muscle activation data. Our results showed that, after 6 min of fast walking, peroneus longus activity increased only in the non-flatfoot group, and gastrocnemius activity increased in the flexible flatfoot group. In the flexible flatfoot group, greater recruitment in abductor halluces and greater fatigue in the tibialis anterior was observed. Individuals with flexible flatfoot showed altered muscle activation pattern after 6-min fast walking. These findings can provide an evidence-based explanation of associated syndromes in flatfoot populations and lead to potential intervention strategies in the future.

The influence of myofascial release on pain and selected indicators of flat foot in adults: a controlled randomized trial

Flat foot pain is a common complaint that requires therapeutic intervention. Currently, myofascial release techniques are often used in the therapy of musculoskeletal disorders. A group of 60 people suffering from flat feet with associated pain. Patients were assigned to four groups (15 people each): MF-myofascial release, E-the exercise program, MFE-myofascial release and the exercise program, C-no intervention. The rehabilitation program lasted 4 weeks. The NRS scale was used to examine pain intensity and FreeMed ground reaction force platform was used to examine selected static and dynamic foot indicators. Statistically significant pain reduction was obtained in all research. A static test of foot load distribution produced statistically significant changes only for selected indicators. In the dynamic test, statistically significant changes were observed for selected indicators, only in the groups subjected to therapeutic intervention. Most such changes were observed in the MF group. In the dynamic test which assessed the support phase of the foot, statistically significant changes were observed only for selected subphases. Most such changes were observed in the MFE group. Both exercise and exercise combined with myofascial release techniques, and especially myofascial release techniques alone, significantly reduce pain in a flat foot. This study shows a limited influence of both exercises and myofascial release techniques on selected static and dynamic indicators of a flat foot.

Effect of Foot Orthoses in Children With Symptomatic Flexible Flatfoot Based on Ultrasonography of the Ankle Invertor and Evertor Muscles

Objective

To examine the changes in the cross-sectional area (CSA) ratio of the ankle invertors and evertors following rigid foot orthosis (RFO) application in children with symptomatic flexible flatfoot and to determine the correlation between the degree of change in CSA ratio and pain-severity after RFO application.

Methods

We included 24 children with symptomatic flexible flatfoot without comorbidities and measured the CSAs of tibialis anterior (TA), tibialis posterior (TP), and peroneus longus (PL) using ultrasonography, resting calcaneal stance position (RCSP) angle, calcaneal pitch (CP), Meary’s angle, talonavicular coverage angle, and talocalcaneal angle using radiography, and foot function index (FFI) at baseline and 12 months after RFO application. We analyzed 48 data by measuring both feet of 24 children. The CSA ratios, the ratio of CSA of each muscle to the sum of CSA of TA, TP, and PL, were also compared. Correlations between the degree of change in FFI, each muscle’s CSA ratio, RCSP angle, and radiographic measurements were investigated.

Results

Following RFO application, significant increase in the PL ratio and CP and significant decrease in the RCSP angle, FFI total, pain, and disability scores were observed. The degree of change in the total score, pain, and disability score of FFI were significantly correlated with the degree of change in the PL ratio and RCSP angle.

Conclusion

RFOs applied to children with symptomatic flexible flatfoot might reduce the compensatory activities of the ankle invertors, thereby increasing the PL ratio, and pain decreases as the PL ratio increases.

Determining the knee joint laxity between the pronated foot and normal arched foot in adult participants

AIM OF THE STUDY

Foot pronation is often associated with increased internal rotation of the lower limb, predisposing the knee joint to greater stress. However, the impact of the pronated foot on knee joint laxity has not been well understood. The study aims to find out the effect of the pronated foot on knee joint laxity.

METHODS

Forty adult participants were recruited for the study: 20 with asymptomatic pronated foot and 20 control subjects with the normal arched foot. Foot assessments were performed by navicular drop test and rearfoot angle measurements. Knee joint laxity was measured by a KT 1000 arthrometer of the dominant leg. An independent t-test was performed to detect the differences between both groups.

RESULTS

Both groups were similar in age, BMI and physical activity level. The findings showed no significant differences between the pronated foot and control group in the knee joint laxity (P = 0.645).

CONCLUSIONS

There were no significant differences in anterior knee displacement between the pronated foot and normal arch foot. The study showed that pronated foot might not be responsible for ACL injuries during the age of twenties and cofounding factors. Further research is needed to investigate older subjects with the pronated foot.

Long-term training on sand changes lower limb muscle activities during running in runners with over-pronated feet

BACKGROUND

Running on sand could be a promising exercise intervention for the treatment of over-pronated feet. However, there is a lack of knowledge about the effects of running on sand on muscle activities. Therefore, this study aims to evaluate the long-term effects of running on sand on the activities of selected lower limb muscles in individuals with OPF compared with healthy controls.

METHODS

Sixty recreational adult male runners with over-pronated feet (foot posture index > 10) were divided into two equal groups (intervention and control). Participants ran barefoot at a pre-defined speed (⁓3.3 m/s) over level stable ground both before and after long-term training on the sand. Muscle activities were recorded using a surface bipolar electromyography system.

RESULTS

For the intervention group, we found a reduced foot posture index (p < 0.001; d = 2.00) and significant group-by-time interactions for gluteus medius activity during the mid-stance phase (p < 0.028; d = 0.59). Significantly higher gluteus medius activity (p = 0.028, d = 0.569) was found during the post-test. We also observed significant group-by-time interactions for medial gastrocnemius activity during the push-off phase (p < 0.041; d = 0.54). Significantly larger medial gastrocnemius activity (p = 0.041; d = 0.636) was found during the post-test compared to the pre-test.

CONCLUSIONS

Long-term running on sand resulted in reduced pronation, increased medial gastrocnemius activity, and improved frontal plane pelvic stability due to higher gluteus medius activity.

TRIAL REGISTRATION

IRCT20191211045704N1. Registered 25 February 2020. Retrospectively registered.

A Three-Dimensional Printed Foot Orthosis for Flexible Flatfoot: An Exploratory Biomechanical Study on Arch Support Reinforcement and Undercut

The advancement of 3D printing and scanning technology enables the digitalization and customization of foot orthosis with better accuracy. However, customized insoles require rectification to direct control and/or correct foot deformity, particularly flatfoot. In this exploratory study, we aimed at two design rectification features (arch stiffness and arch height) using three sets of customized 3D-printed arch support insoles (R+U+, R+U-, and R-U+). The arch support stiffness could be with or without reinforcement (R+/-) and the arch height may or may not have an additional elevation, undercutting (U+/-), which were compared to the control (no insole). Ten collegiate participants (four males and six females) with flexible flatfoot were recruited for gait analysis on foot kinematics, vertical ground reaction force, and plantar pressure parameters. A randomized crossover trial was conducted on the four conditions and analyzed using the Friedman test with pairwise Wilcoxon signed-rank test. Compared to the control, there were significant increases in peak ankle dorsiflexion and peak pressure at the medial midfoot region, accompanied by a significant reduction in peak pressure at the hindfoot region for the insole conditions. In addition, the insoles tended to control hindfoot eversion and forefoot abduction though the effects were not significant. An insole with stronger support features (R+U+) did not necessarily produce more favorable outcomes, probably due to over-cutting or impingement. The outcome of this study provides additional data to assist the design rectification process. Future studies should consider a larger sample size with stratified flatfoot features and covariating ankle flexibility while incorporating more design features, particularly medial insole postings.

The Prevalence and Factors Associated with Low Back Pain Among People with Flat Feet

Background

A positive relationship between flat feet and low back pain (LBP) has not gained consensus in literature. The aim of this study was to determine the prevalence and factors associated with low back pain (acute and chronic) among individuals with flat feet.

Methods

In 2018, a cross-sectional study was conducted at a national festival in Saudi Arabia, and 1798 adult visitors were invited to participate in face-to-face interviews. Participants' characteristics were stratified by the type of foot and they were questioned on acute low back pain (ALBP) or chronic low back pain (CLBP). The odds ratio (OR) were presented as a measure of this association, followed by a multivariate analysis.

Results

The prevalence of LBP among participants with flat feet was 65.9%, among whom 51.6% suffered ALBP and 48.4% suffered from CLBP. Flat feet increased the chances of having ALBP by 3.28 times and CLBP by 4.5 times. After stratification, ALBP and CLBP were both significantly higher among all participants with flat feet in comparison with their counter groups. Multivariate analyses showed that females were more likely to complain of ALBP. Participants who did no physical activity were more likely to complain of ALBP. Female participants and older participants were more likely to complain of ALBP and CLBP.

Conclusion

Flat feet are associated with both ALBP and CLBP. Significant factors of low back pain also included sex, age, occupation, and physical activity.

Pes Planus Foot among the First and Second Year Medical Students of a Medical College: A Descriptive Cross-sectional Study

Introduction:

Foot is a complex segmented structure formed by the articulation of 26 different bones which are held together by multiple ligaments, extrinsic tendons and the intrinsic muscles of the feet. The assessment of median longitudinal arch serves as an important reference in determining the degree of pes planus or pes cavus. This study aims to find the prevalence of pes planus among the undergraduate medical students of a medical college.

Methods:

A descriptive cross-sectional study was carried out in the first- and second-year undergraduate medical students of a teaching hospital after taking ethical approval from Institutional Review Committee. The study was conducted from 15th November 2019 to 14th November 2020. Eighty-seven participants were involved in study using the random sampling technique. Foot prints were collected from the participants in the A4 size paper after applying ink over plantar surface of the foot. Measurements were done using the Autodesk Autocad software. Statistical Package for the Social Sciences was used. Point estimate at 95% Confidence Interval was calculated along with frequency and proportion for binary data.

Results:

Out of the total subjects, 14 (8.04%) (5.14-10.94 at 95% Confidence Interval) presented with flat foot. Similarly, high arched foot was seen in 29 (16.67%) of subjects whereas normal arched foot was seen in 131 (75.29%) subjects.

Conclusions:

From the current study we conclude that the prevalence of pes planus was slightly higher than that compared with the similar studies.

Quality of Life in Young Adults after Flatfoot Surgery: A Case-Control Study

The true impact of surgery for flatfoot deformities on patient's quality of life and health status remains poorly defined. The aim of this study is to evaluate the quality of life and the return to daily tasks and sports or physical activities in young adults after surgical correction of flatfoot deformity. Patients treated for bilateral symptomatic flat foot deformity were retrospectively studied. The healthy control group comprised a matched reference population with no history of foot surgery or trauma that was voluntary recruited from the hospital community. All subjects were asked to fill out questionnaires centered on the assessment of the health-related quality of life (Short-form 36; SF-36) and physical activity (International Physical Activity Questionnaire; IPAQ). Most study group SF-36 subscales were lower when compared to the control group. Among the study group, post-operatively, 36.6% of patients managed to resume low levels of sports activity, 40% were sufficiently active and were able to perform moderate sports activity (an activity that requires moderate physical effort and which forces the patient to breathe with a frequency only moderately higher than normal), while 23.3% of them were active or very active and were able to perform intense physical activity. Most IPAQ scores were statistically different from the control group. The present study suggests that patients treated with medializing calcaneal osteotomy and navicular-cuneiform arthrodesis for symptomatic flafoot had lower levels of quality of life and physical activity when compared to healthy subjects. After surgery, patients showed a significant improvement in the clinical scores.

Finite element analysis of subtalar joint arthroereisis on adult-acquired flexible flatfoot deformity using customised sinus tarsi implant

Background

Subtalar arthroereisis may cause sinus tarsi pain complications. In this study, we aimed to introduce a customised implant that facilitated treatment effect and less impingement. The biomechanical outcome between the intact and implant conditions was compared using finite element analysis.

Methods

A female patient with flatfoot (age: 36 years, height: 156 ​cm, body mass: 51 ​kg) was recruited as the model patient. The customised implant was designed from the extracted geometry. Boundary and loading conditions were assumed from the data of a normal participant. Four gait instants, including the ground reaction force first peak (25% stance), valley (45%), initial push-off (60%) and second peak (75%) were analyzed.

Results

The navicular height was elevated by 4.2% at 25% stance, whereas the strain of the spring, plantar cuneonavicular and plantar cuboideonavicular ligaments were reduced. The talonavicular joint force decreased and the calcaneocuboid joint increased by half and 67%, respectively, representing a lateralised load pathway. There was a stress concentration at the sulcus tali reaching 15.29 ​MPa

Conclusion

Subtalar arthroereisis using a customised implant may produce some positive treatment effects in terms of navicular height elevation, ligament strain relief and lateralised joint loading pathway. Although the concentrated stress at the sulcus tali did not exceed the threshold of bone breakdown, we could not rule out the potential of vascular disturbance owing to the remarkable elevation of stress. Future study may enlarge the contact area of the bone–implant interface by considering customisation based on the dynamic change of the sinus tarsi during walking gait.

The translational potential of this article

Geometry mismatch of prefabricated implants could be the reason for complications. With the advancement of 3D printing, customising implant becomes possible and may improve treatment outcome. This study implemented a theoretical model approach to explore its potential under a simulation of walking.

The Design and Application of Simplified Insole-Based Prototypes with Plantar Pressure Measurement for Fast Screening of Flat-Foot

This study aimed to find the correlation between conventional Arch Index (AI) measurements and our prototype of a simplified insole-based plantar pressure measurement system and to find out the effective plantar pressure sensor position. Twenty-one subjects participated in this study, which was divided into two groups: 10 subjects with flatfoot and 11 subjects with normal foot. Five force sensitive resistance sensors were used on this prototype using Arduino as the data acquisition device. Two types of trials, namely static and dynamic, were conducted to validate our system against the ink-type AI measurement as a golden standard. The results showed that in the static trial, there was a high linear correlation with the medial arch sensor configuration, while in the dynamic trial, there was a high linear correlation in the medial arch sensor configuration and sensor 5 configuration. This study showed that both static and dynamic tests using the self-developed device could effectively determine most of the flatfoot subjects and suggests that in the future, it can be applied in clinical applications because of its advantages when compared to the expensive-high tech graphic input board and conventional tools, like ink-type based measurements.