Examination of the Correlation Between Foot Morphology Measurements Using Pedography and Radiographic Measurements

A foot structure study of new arch flexibility grading system based on three-dimensional arch volume

PURPOSE

Different arch structures may cause different foot function injuries. In the past, the arch structure and flexibility of the foot were often defined by the height of the arch, and there was no three-dimensional (3D) structure classification method. In order to form a more complete 3D description, we propose a new classification system of arch volume flexibility (AVF), and then use this new classification system to investigate the relationship between the AVF and arch index (AI), and the arch height flexibility (AHF) and AI, respectively.

METHODS

It is proposed to recruit 180 young male adults for the test. We obtained arch volume and AI through 3D scanning and obtained the navicular height through manual measurement. Based on these data, we calculated the AHF and the AVF. Using the quintile method, these arches are divided into very stiff, stiff, neutral, flexible, and very flexible. According to AI value, all arches were divided into cavus, rectus, and planus. The distribution of AVF was compared using χ2 goodness of fit test. The spearman correlation test was used to compare the AHF and AVF. A p < 0.05 indicates that the difference is statistically significant.

RESULTS

All participants' plantar data was obtained through 3D scanning, but only 159 of them were complete, so only 318 feet had valid data. The left AHF is (21.23 ± 12.91) mm/kN, and the right AHF is (21.71 ± 12.69) mm/kN. The AVF of the left foot arch is (207.35 ± 118.28) mm3/kg, while the right one is (203.00 ± 117.92) mm3/kg, and the total AVF of the arch was (205.17 ± 117.94) mm3/kg. There was no statistical difference in the AVF between the left and right feet for the same participant (n = 159, p = 0.654). In cavus, the percentage of arch with AVF is 21.4% (very stiff), 21.4% (stiff), 14.3% (neutral), 7.1% (flexible), and 35.7% (very flexible). In rectus, the percentage of arch with AVF is 23.9% (very stiff), 19.6% (stiff), 14.7% (neutral), 24.5% (flexible), and 17.2% (very flexible). In planus, the percentage of arch with AVF is 14.9% (very stiff), 20.6% (stiff), 27.0% (neutral), 16.3% (flexible), and 21.3% (very flexible). Moreover, the correlation between AHF and AVF is not significant (p = 0.060).

CONCLUSION

In cavus, rectus, and planus, different AVF accounts different percentage, but the difference is not statistically significant. AVF is evenly distributed in the arches of the feet at different heights. We further found the relationship between AHF and AVF is not significant. As a 3D index, AVF may be able to describe the flexibility of the arch more comprehensively than AHF.

Isokinetic Analysis of Flexible Flatfoot: Is It a Weakness of Proprioception and Muscle Strength?

BACKGROUND

Although flexible flatfoot (FF) in children is a foot deformity that is frequently encountered in daily orthopedics practice, its etiology is still controversial. The aim of this study was to determine whether there is a weakness in muscle strength and proprioception in patients with FF.

METHODS

The study group consisted of 16 cases with FF, and the control group consisted of 25 volunteers with normal feet. An isokinetic dynamometer was used to assess muscle strength and proprioception of movement directions of plantarflexion, dorsiflexion, eversion (EV), and inversion (INV) in both groups.

RESULTS

There was no statistically significant difference between the groups in strength of plantarflexion and dorsiflexion muscles, whereas in the control group, proprioception of all four movement directions and strengths of the EV and INV muscles were found to be statistically significantly higher (P < .05).

CONCLUSIONS

There is weakness in EV and INV muscle strength and proprioception disorder in patients with FF. We recommend conducting further studies that validate muscle weakness and proprioception disorders with different study designs and evaluate the effectiveness of improving muscle strength and proprioception weakness in FF.

Arch volume：a new method for medial longitudinal arch measurement

BACKGROUND

As a flexible and elastic structure, the dynamic morphometry of medial longitudinal arch remains to be an unresolved Issue for clinic. Here we introduce a new measurement named arch volume to describe the morphological changes of the medial longitudinal arch during weight-bearing and compare with present method for measuring MLA.

METHODS

64 healthy participants were enrolled. And the dynamic arch morphology was measured under four weight bearing status with navicular height, arch area and arch volume, respectively.

RESULTS

With the increase of weight loading, the flattening or slightly deformation of medial longitudinal arch was observed by all method (p<0.05). However, as a 3D indicator, arch volume not only showed higher sensitivity than other method, but also provide visualization of MLA during loading changing.

CONCLUSIONS

Compared with navicular height and arch area, arch volume has a significant advantage in describing arch morphological changes under different weight bearing status.

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.

Does the way of weight-bearing matter? Single-leg and both-leg standing radiographic and pedobarographic differences in pediatric flatfoot

BACKGROUND

An exact definition is lacking for the term "weight-bearing" or different standing modalities when implementing foot radiographs for children and adults; moreover, only few studies have investigated the relationship between radiographic and pedobarographic measurements.

RESEARCH QUESTION

We hypothesized that the method of weight-bearing in single-leg and both-leg standing positions could influence the measurement results in radiographs and the distribution of foot pressure.

METHODS

This prospective study evaluated 33 children (66 feet) with flexible flatfoot deformities scheduled for subtalar screw arthroereisis surgery. Radiographs in the lateral and anteroposterior (AP) views were assessed independently in the single-leg and both-leg standing positions. Static pedobarography was performed as that for measuring weight-bearing. Standardized radiographic angles and pedobarographic data were analysed and correlated.

RESULTS

There were differences in radiographic measurements between the single-leg and both-leg standing positions, including the AP talocalcaneal angle (p = 0.032), AP talus-first metatarsal base angle (p = 0.003), AP talus-first metatarsal angle (p = 0.003), lateral calcaneal pitch angle (p = 0.001), talus-first metatarsal index (p = 0.004), and talocalcaneal index (p = 0.029). Moreover, differences between these two standing modalities were found in most of the static pedobarographic data, including the contact area (p = 0001), maximal force (p = 0.001), and peak pressure (p = 0.007). Overall, medial foot pressure increased more in both-leg standing than in the single-leg standing position, whereas radiographic measurements showed a more pronounced flatfoot deformity in the single-leg standing position. The AP talus-first metatarsal angle was the only angle or index with a significant association to some pedobarographic measurements in both standing modalities.

SIGNIFICANCE

As there are significant differences between single-leg standing and both-leg standing radiographic and static pedobarographic values, observers have to be precise in the definition of "weight-bearing" to gain reproducible and comparable study values in children and adults. We recommend acquiring both-leg standing foot radiographs because children with flexible flatfeet can stand more steadily in this position than in the single-leg standing position.

Development of a quantitative measurement system for three-dimensional analysis of foot morphology using a smartphone

Existing techniques for measuring foot morphology are invasive or cumbersome. A new technique was developed using a smartphone, which can measure foot morphology to within 1 mm. This is shown to be applicable to the prediction of hallux valgus, which allows for early intervention.

Reproducibility of radiographic methods for assessing longitudinal tarsal axes: Part 1: Consecutive case study

INTRODUCTION

Calcaneal pitch angle and Meary's angle are commonly used to assess longitudinal foot arches on lateral-view radiographs. However, the methods used to obtain the talar, first metatarsal, calcaneal, and plantar axes differ across multiple reports, and no study has evaluated the reproducibility of these approaches. The aim of this study was to determine the most reproducible methods for radiographically evaluating longitudinal axes.

METHODS

Standing radiographic images of 40 feet from 21 consecutive outpatients were obtained to measure longitudinal axes of the talus, first metatarsal, calcaneus and plantar surface, which were defined using six, five, four and three different methods, respectively, selected from previous reports. Intraobserver and interobserver correlation coefficients were calculated.

RESULTS

The best intraobserver and interobserver correlation coefficients for the talar, first metatarsal, and calcaneal axes were obtained using methods involving a line bisecting the angle formed by the lines tangential to the superior and inferior margins of the talus, a line connecting the centre of the first metatarsal head and the midpoint of the visualized base of the first metatarsal, and a line drawn tangential to the inferior surface of the calcaneus, respectively. For the plantar axis, a method that used the horizontal plane (as a reference axis) was regarded as the best approach, although intraobserver and interobserver correlation coefficients could not be calculated because all values were zero.

CONCLUSIONS

The aforementioned methods were considered to be optimal for the radiographic assessment of longitudinal foot arches. This study could contribute to more accurate assessments of foot deformities.

Reliability of a New Method to Determine Foot Arch Height for Clinicians

BACKGROUND

Arch height is an important indicator of risk of foot pathology. The current non-invasive gold standard based on footprint information requires extensive pre-processing. Methods used to obtain arch height that are accurate and easier to use are required in routine clinical practice.

METHODS

The proposed arch index diagonals (AI_d) method for determining the arch index (AI) reduces the complexity of the preprocessing steps. All footprints were first prepared as required by the Cavanagh and Rodgers method for determining the AI and then compared to the proposed diagonals method. Results were classified according to the Cavanagh and Rodgers cut-off values into three groups of low, normal and high AI. ANOVA and Tukey's post hoc tests were applied to identify significant differences between AI groups. Linear modeling was applied to determine the fit of the new AI_d method compared to the Cavanagh and Rodgers AI.

RESULTS

One hundred and ninety-six footprints were analyzed. The ANOVA indicated significant differences between the groups for AI_d (F1,194=94.49, p<0.0001) and the Tukey post hoc tests indicated significant differences between the pair-wise comparisons (p<0.001). Linear modeling indicated that the AI_d ratio classified more footprints in the high arch group compared to Cavanagh and Rodgers results (R²=32%, p< 0.01). Intra- and inter-rater correspondence was above 90% and confirmed that the AI_d results provided a better indication of arch height.

CONCLUSIONS

The proposed method simplifies current processing steps to derive the arch height.