Radiographic measurements of the talus and calcaneus in the adult pes planus foot type

Statistical shape modeling of mean shape and principal variability of the human talar bone in the Chinese population

PURPOSE

The talar bone plays a crucial role in ankle biomechanics and stability. Understanding the shape variability of the talar bone within specific populations is essential for various clinical applications. In this study, we aimed to investigate the mean shape and principal variability of the human talar bone in the Chinese population using statistical shape modeling (SSM).

METHODS

CT scans of 214 tali were included to create SSM models. Principal component analysis was used to describe shape variation among the male, female, and overall groups.

RESULTS

The largest amount of variation among three groups ranges from 17.2%-18.8% of each variation. The first seven principal components (modes) captured 62.4%-67.5% of the cumulative variance. No dominant shape of the talus was found. Male tali generally have a larger size than the female tali, with the exception of the articular surface of the anterior subtalar joint.

CONCLUSIONS

SSM is an effective method of finding mean shape and principal variability. Considerable variabilities were noticed among these three groups and all principal modes of variation. No dominant talar model was found to represent the majority of tali, regardless the gender. Such information is crucial to improve the current understanding of talar pathologies and their treatment strategies.

A Novel Deep Transfer Learning-Based Approach for Automated Pes Planus Diagnosis Using X-ray Image

Pes planus, colloquially known as flatfoot, is a deformity defined as the collapse, flattening or loss of the medial longitudinal arch of the foot. The first standard radiographic examination for diagnosing pes planus involves lateral and dorsoplantar weight-bearing radiographs. Recently, many artificial intelligence-based computer-aided diagnosis (CAD) systems and models have been developed for the detection of various diseases from radiological images. However, to the best of our knowledge, no model and system has been proposed in the literature for automated pes planus diagnosis using X-ray images. This study presents a novel deep learning-based model for automated pes planus diagnosis using X-ray images, a first in the literature. To perform this study, a new pes planus dataset consisting of weight-bearing X-ray images was collected and labeled by specialist radiologists. In the preprocessing stage, the number of X-ray images was augmented and then divided into 4 and 16 patches, respectively in a pyramidal fashion. Thus, a total of 21 images are obtained for each image, including 20 patches and one original image. These 21 images were then fed to the pre-trained MobileNetV2 and 21,000 features were extracted from the Logits layer. Among the extracted deep features, the most important 1312 features were selected using the proposed iterative ReliefF algorithm, and then classified with support vector machine (SVM). The proposed deep learning-based framework achieved 95.14% accuracy using 10-fold cross validation. The results demonstrate that our transfer learning-based model can be used as an auxiliary tool for diagnosing pes planus in clinical practice.

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.

Foot Deformity Correction Planning in the Sagittal Plane Based on the Vitruvian Foot First Metatarsal Mechanical Axis and Calcaneus Anatomic Axis

The aim of the study was to test a novel planning method for simultaneous midfoot and hindfoot deformity correction, based on reference lines and angles (RLA) of the talus, calcaneus and first metatarsal in 64 normal radiographs from 55 patients. Talus Joint Line (TJL), from the border of the articular surface of the talus and the posterior process of talus, and mechanical axis of the first metatarsal form the mechanical Lateral Talometatarsal Angle (mLTMA) = 23.6º (±3.2). The length of the first metatarsal line was measured from its intersections with the TJL and first metatarsal head and it was 4.3 (±0.94) times longer that TJL (k). For hindfoot correction planning, we used an axis of the calcaneus formed by a line starting at the middle of the back of the calcaneal tuberosity and going perpendicular to a line from the top point to the bottom point of the calcaneal tuberosity. The intersection of the calcaneal line and the anterior continuation of TJL form the lateral heel angle (LHA) = 15.2º (±3.4).The following parameters were identified: the length from the intersection point of the lines and anterior point of TJL was 2.56 ± 1.1 longer than TJL (k1). The length from the intersection point and posterior border of the calcaneus was 4.59 ± 1.0 times longer than TJL (k2). Planning using the new method was demonstrated and confirmed on 3 case examples. A novel method for analysis and planning of midfoot and hindfoot sagittal plane deformity correction may be used separately or simultaneously for complex deformity correction.

Is Arthrodesis Sufficient in the Setting of Complex, Severe and Rigid Progressive Collapsing Foot Deformities?

Arthrodesis of the hindfoot is typically used for the correction of severe and arthritic progressive collapsing foot deformity. Concomitant bony or soft tissue procedures may be helpful in patients with congenital abnormalities including the ball-and-socket ankle or congenital vertical talus. Dysplasia of the hindfoot bones may be more common than previously recognized, and corrective procedures or alterations in technique may need to be performed during hindfoot arthrodesis to account for bony deformity. Intraarticular osteotomies, extraarticular osteotomies, tendon lengthening, and tendon transfer procedures may be used in specific instances to aid in deformity correction and improve overall function.

Validity of a simple footprint assessment board for diagnosing the severity of flatfoot: a prospective cohort study

BACKGROUND

A simple, non-quantitative, and cost-effective diagnostic tool would enable the diagnosis of flatfoot without need for specialized training. A simple footprint assessment board that investigates which toe the cord passes through from the centre point of the heel to the most lateral point of the medial contour of the footprint has been developed to assess flatfoot. The purpose of this study was to verify the validity of a simple footprint assessment board for flatfoot.

METHODS

Thirty-five consecutive patients with foot pain, foot injury, or any associated symptoms who underwent computed tomography (CT) were analysed prospectively. At the time of the CT scan, a footprint analysis using a simple footprint assessment board was performed. The navicular index, tibiocalcaneal angle, and calcaneal inclination angle were evaluated by CT to assess flat feet. These three criteria were compared to those evaluated with the simple footprint assessment board by regression analysis. In addition, the same analysis was conducted separately for young, middle-aged, and older patients in order to investigate each age group.

RESULTS

The navicular index and tibiocalcaneal angle generally decreased as the score of the simple footprint assessment board increased. Calcaneal inclination angle generally increased as the score of the simple footprint assessment board increased. As the scores of the simple footprint assessment board decreased by approaching the great toe, the navicular index and tibiocalcaneal angle were higher and calcaneal inclination angle was lower, which is indicative of a higher likelihood of flatfoot. The scores derived from the simple footprint assessment board was correlated with these three criteria measured by CT, not only when the result of simple footprint assessment board was set as a non-continuous variable but also when the result was set as a continuous variable. The results of the age-stratified survey were similar for all groups.

CONCLUSIONS

The findings of this study suggest that a simple footprint assessment board can be potentially useful to detect flatfoot.

TRIAL REGISTRATION

Retrospectively registered.

Calcaneus height is a key morphological factor of sprint performance in sprinters

This study examined the relationships between the foot bone morphologies and sprint performance in sprinters. Foot images in 56 male sprinters obtained using magnetic resonance imaging. The relative lengths of the forefoot bones of the big and second toes, which were calculated as total lengths of the forefoot bones for each toe normalized to the foot length, correlated significantly with personal best 100-m sprint time (r =  − 0.293 and − 0.459, both Ps < 0.05). The relative lengths of the rearfoot talus and calcaneus normalized to the foot length also correlated significantly with the sprint performance (r =  − 0.378 and − 0.496, both Ps < 0.05). Furthermore, the relative height of the calcaneus, but not the talus, normalized to body height correlated significantly with sprint performance (r =  − 0.690, P < 0.001). Additionally, the relative calcaneus height correlated significantly with the foot arch height index (r = 0.420, P = 0.001), and the foot arch height index correlated significantly with sprint performance (r =  − 0.517, P < 0.001). These findings suggest that the taller calcaneus may be a key morphological factor for achieving superior sprint performance, potentially via modeling the longer forefoot and rearfoot bones and functional foot morphology in sprinters.