Search Results (38)

(1) Background: The paper focuses on foot biomechanics in static situations. The aim was to determine the distribution of the load exerted by the human body on the ground in order to establish reference points on the foot for correct human body posture. (2) Methods: A model was developed to describe the body weight-ground relationship, consisting of a support platform and a part imitating the rest of the human body. Experiments consisted of tilting the general centre of gravity from the maximum forward through midfoot, a passive, neutral position, to the maximum backwards while maintaining balance. The ground load was measured in each position. (3) Results: The loads of the front and rear parts of the support platform and the resultant load force at different degrees of body tilt were calculated. It has been shown that at the maximum inclination of the body to the extreme support point, the entire weight falls on this point. For the neutral position (in the Basic Balance Point), the load on the front and rear parts of the support platform was 26% and 74%, and 40% and 60% for the passive position (in the Passive Balance Point). (4) Conclusions: The distribution of body weight on the ground is determined by the projection of the general centre of gravity on the ground through the feet. The resultant ground reaction force defines both the magnitude and direction of the load exerted on the support platform. Ground reaction forces associated with body weight were assessed at five anatomical points of the foot: the forefoot, rearfoot, midfoot, and the Passive and Basic Balance Point. In an upright standing posture, the projection of the general centre of gravity fluctuates between the Passive and Basic Balance Point, corresponding to the passive and neutral positions, respectively. Only in the neutral position, the body’s weight, as concentrated in the general centre of gravity, falls on the axis of the upper ankle joint and distributes the load between the forefoot and rearfoot. Determining the correct distribution of foot loads may serve in the future to study abnormalities in human body posture Full article

As populations age, particularly in countries like Japan, mobility impairments related to ankle joint dysfunction, such as foot drop, instability, and reduced gait adaptability, have become a significant concern. Active ankle–foot orthoses (AAFO) offer targeted support during walking; however, most existing systems rely on rule-based or threshold-based control, which are often limited to sagittal plane movements and lacking adaptability to subject-specific gait variations. This study proposes an approach driven by neuromuscular activation using surface electromyography (EMG) and a Gated Recurrent Unit (GRU)-based deep learning model to predict plantar pressure distributions at the heel, midfoot, and toe regions during gait. EMG signals were collected from four key ankle muscles, and plantar pressures were recorded using a customized sandal-integrated force-sensitive resistor (FSR) system. The data underwent comprehensive preprocessing and segmentation using a sliding window method. Root mean square (RMS) values were extracted as the primary input feature due to their consistent performance in capturing muscle activation intensity. The GRU model successfully generalized across subjects, enabling the accurate real-time inference of critical gait events such as heel strike, mid-stance, and toe off. This biomechanical evaluation demonstrated strong signal compatibility, while also identifying individual variations in electromechanical delay (EMD). The proposed predictive framework offers a scalable and interpretable approach to improving real-time AAFO control by synchronizing assistance with user-specific gait dynamics. Full article

(1) Background: Plantar heel pain (PHP), a common overuse foot injury, significantly impacts runners. While the mechanical role of the plantar fascia during gait is established, its effect on foot function during running, particularly foot joint coupling, remains unclear. This study investigated foot joint coupling during running in runners with and without PHP using statistical parametric mapping (SPM). (2) Methods: Thirteen uninjured runners (seven m, six f; age = 30.5 ± 5.9 years; BMI = 23.5 ± 3.0 kg/m²) and thirteen runners with PHP (six m, seven f; age = 29.0 ± 8.0 years; BMI = 23.1 ± 2.0 kg/m²) performed running trials at 4.0 m/s. A seven-segment foot model that defined six functional articulations (rearfoot, medial and lateral midfoot, medial and lateral forefoot, first metatarsophalangeal) was used to quantify foot kinematics, vector coding was used to calculate joint coupling between adjacent foot segments, and SPM was used to analyze joint stance phase coupling angles. (3) Results: There were statistically significant differences in rearfoot frontal plane–medial midfoot frontal plane joint coupling between runners with and without PHP from 69 to 70% stance phase (mean difference = 39.41°) and at 76% stance (mean difference = 47.89°). The differences were indicative of greater medial midfoot eversion rotation relative to rearfoot complex inversion in the PHP group. (4) Conclusions: The difference in the rearfoot complex and medial midfoot frontal plane coupling occurred during the propulsion phase of the running stance when the foot should be transitioning to a more supinated position, which may reflect compromised supination due to plantar fascia degeneration. Full article

Since its introduction, weight-bearing computed tomography (WBCT) has gained prominence due to its ability to produce accurate three-dimensional images under natural loading conditions, making it particularly useful for assessing complex foot deformities. This review aimed to focus on the diseases of the foot and categorized the pathological conditions into forefoot disease (hallux valgus), midfoot disease (Lisfranc injuries and midfoot osteoarthritis), and progressive collapsing foot deformity. For each category, the authors detail how WBCT enhances diagnostic accuracy and informs treatment strategies. In hallux valgus, WBCT allows for more precise measurement of established parameters and reveals crucial information about metatarsal pronation and ray instability. For midfoot pathologies, WBCT’s superiority in detecting subtle Lisfranc injuries and characterizing midfoot osteoarthritis is emphasized, highlighting the development of novel measurement techniques. The review extensively covers the application of WBCT in assessing the complex three-dimensional features of PCFD, including hindfoot valgus, midfoot/forefoot abduction, medial column instability, peritalar subluxation, and valgus tilting, presenting several WBCT-specific measurements and the use of distance mapping to quantify joint surface interaction. The authors conclude that WBCT, potentially enhanced through integration with artificial intelligence (AI), represents a significant advancement in foot and ankle care, promising improved diagnostic accuracy, streamlined treatment planning, and, ultimately, better patient outcomes. Full article

Background/Objectives: This study aims to examine the effects of clinical exercise training on foot plantar pressure, the subtalar joint, and the gait cycle during pregnancy. Methods: The study was planned as a randomized, controlled, and single-blind study. Participants’ demographic information, obstetric evaluation, physical activity level, fall history, and pain evaluation were recorded. Foot plantar pressure, the subtalar joint, and the gait cycle were measured through pedobarography at Gait Laboratory. The control group was recommended walking. Clinical exercise training was given to the study group 2 days a week for eight weeks. Evaluations were made on day 0 and the day corresponding to the end of week 8. Results: The study was completed with 50 people in the study group (age: 29.7 ± 3.8 years) and 51 in the control group (age: 29.1 ± 6.1 years). As a result of the parametric and non-parametric tests performed before and after the exercise, it was observed that there was a statistically significant difference between the two groups in weight, BMI, pain score, static plantar pressure, dynamic plantar pressure, subtalar joint flexibility, duration of the walking period, and multistep walking speed (p < 0.01). The two groups had a significant difference only in the dominant midfoot plantar pressure (p > 0.05). Conclusions: According to our research, weight control and pain relief are observed in women who engage in clinical exercise in the second trimester of pregnancy; plantar pressure and subtalar joint flexibility are preserved, the walking period does not increase, and the multistep walking speed can be maintained after eight weeks. Full article

Gait analysis with optical motion capture typically treats the foot as a single segment, which can measure clinically useful kinematics but is insufficient to measure the kinematics of joint motions within the foot. This study hypothesizes that a four-segment foot model, tracking the hindfoot, midfoot, forefoot, and hallux, can accurately measure intrinsic foot kinematics when validated against the gold standard of fluoroscopic X-ray radiostereometric analysis (RSA) during walking gait. Ten healthy volunteers were tested, with the left foot tracked during the stance phase from heel strike to toe off. The results indicated that the height-to-length ratio of the medial longitudinal arch (MLA) and the transverse plane motion of the hindfoot were the most reliable kinematic measures, showing the best agreement between the optical motion capture and RSA methods. In contrast, the frontal plane motions of the hindfoot and forefoot showed the greatest differences, though these were not statistically significant at p < 0.05. These findings demonstrate that the multi-segment foot model is a valid method for measuring intrinsic foot kinematics in a clinical setting, providing a reliable alternative to more invasive techniques. Full article

Objectives: X-linked hypophosphatemia (XLH, OMIM 307800) is a rare genetic disorder that affects phosphate metabolism. While lower limb deformity represents a hallmark symptom of patients with XLH, the effect on the foot has not been investigated. This study aimed to characterise foot pathologies and assess related outcome scores in adolescents and adults with XLH. Methods: Patients aged ≥ 16 years with genetically verified XLH were included in this study. Physical examination was performed, and foot scores as well as foot X-rays were assessed. Radiographic analysis included the assessment of osteoarthritis, enthesopathies, and alignment abnormalities. Results: Twenty-six participants (51 limbs) with a mean age of 33.9 ± 15.4 years were eligible for the study. Patients with XLH presented with flatfoot deformity (reduced Meary angles > −4° in 84.3%), elevated first and fifth metatarsal angles > 30° (IM 1–5, 53.5%) and hallux valgus angles > 15° (36.0%). Moderate-to-severe joint space narrowing was observed in the talonavicular (49%) and cuneonavicular joints (41.2%). The American Orthopedic Foot and Ankle Society (AOFAS) score was associated with mildly reduced midfoot function. Conclusions: A high rate of bony deformity, joint degeneration, and decreased foot scores indicated the impact of forefoot and midfoot disorders in patients with XLH. Full article

The first metatarsophalangeal joint (MTPJ) and the first ray are crucial in walking, particularly during propulsion. Limitation in this joint’s sagittal plane motion, known as hallux limitus, can cause compensatory movements in other joints. Some studies assessed the impact of various foot orthoses designs on the foot biomechanics; however, a comprehensive understanding is lacking. This study compared the effects of two custom-made foot orthoses (CFOs) on the foot joint kinematics and kinetics in patients with structural hallux limitus (SHL). In this quasi-experimental study, 24 patients with hallux limitus were assessed in three conditions: (i) barefoot, (ii) shod with a cut-out custom foot orthosis (cut-out CFO), and (iii) shod with an anterior forefoot-stabilized element custom foot orthosis (AFSE CFO), fitted into a minimalist neoprene shoe. Multi-segment foot kinematics and kinetics were assessed during the stance phase of the gait. A decrease in ankle and midfoot inversion, as well as in ankle plantarflexion, was found in both orthotic conditions. Regarding the first MTPJ, a greater dorsiflexion was observed with the patient being barefoot compared to both of the conditions under study. From the current finding, it should be concluded that neither of the custom foot orthoses produced the predefined functional effects. Full article

Adult-acquired flatfoot has been considered to arise from tibialis posterior tendon deficiency. Recent evidence shows that arch stability is mainly maintained by structures such as plantar fascia and spring ligament. The dysfunction of these ’passive’ stabilizers results in loss of arch integrity that causes forefoot pronation and reactive tendon overload, especially in the tibialis posterior tendon and peroneus longus tendon. The peroneus longus tendon (PLT) spans several midfoot joints and overloads with arch lengthening. The biomechanical stress/changes that occurs in this tendon are not well recognized. This study evaluates the biomechanical consequences that fusions have on peroneus longus tendon stresses in soft-tissue deficiencies associated with flatfoot deformity. A complete computational human foot model was used to simulate different scenarios related to the flatfoot deformity and associated common midfoot/hindfoot fusions, to quantify the biomechanical changes in the peroneus longus tendon. The results showed that the stress of the peroneus longus tendon is especially affected by the fusion of hindfoot joints and depends on the soft tissue types that fail, causal in generating the flatfoot. These results could be useful to surgeons when evaluating the causes of flatfoot and the secondary effects of surgical treatments on tissues such as the peroneus longus tendon. Full article

Approximately 90% of patients with arthritis exhibit forefoot deformities, including deformities within the metatarsophalangeal and proximal interphalangeal joints. Current pharmacological treatment with Disease Modifying Antirheumatic Drugs (DMARDs) consists of two groups: synthetic drugs (sDMARDs) and biological drugs (bDMARDs). The objective of our study was to investigate foot anthropometry changes in RA patients based on the administered treatment over a five-year period Method: A longitudinal analysis was conducted with RA patients who were grouped based on their pharmacological treatment. The pharmacological treatment groups were categorized into (I) methotrexate (MTX), (II) MTX plus biological treatments (including all variables), (III) biological treatment alone, and (IV) a miscellaneous group comprising patients with diverse treatments, including patients for whom various drugs had failed or who had not achieved remission with pharmacological treatment. For the anthropometric measurements, a foot measurement platform validated by McPoil et al. was used. Post hoc analyses with Bonferroni correction were performed to identify pairwise differences between the treatment groups while controlling for Type I errors due to multiple comparisons. Results: In the period from 2018 to 2023, significant changes were observed in several foot measurements. For instance, the MTX group showed a statistically significant increase in left heel width (p = 0.026). The MTX group experienced a slight increase in left foot length, while the Biologics and MTX + Bio groups exhibited more substantial increases in both maximum medial arch height and midfoot width. Conclusions: Different RA treatments can have a significant impact on foot structure over a five-year period, showing notable changes in heel width and overall foot morphology. Combined treatments with MTX and biologics potentially offer better management of RA. Full article

This study investigates the sagittal plane dynamics of the foot, particularly the metatarsophalangeal (MTP) joint and medial longitudinal arch (MLA) movements, in relation to obesity and foot health. The kinematics of the MTP and arch joints were measured in 17 individuals with class 2–3 obesity (BMI > 35 kg/m²) and 10 normal-weight individuals (BMI ≤ 24.9 kg/m²) using marker-based tracking. Analysis was conducted during heel lifting while seated and during walking at self-selected speeds. The results indicated that obese participants exhibited 20.92% greater MTP joint dorsiflexion at the end of the push-off phase and 19.84% greater MLA compression during the stance phase compared to normal-weight controls. However, no significant differences were found in the kinematic joint coupling ratio. While these findings reveal the different biomechanical behaviors of the MTP joint and MLA in obese compared to normal-weight individuals, it is important to interpret the implications of these differences with caution. This study identifies specific biomechanical variations that could be further explored to understand their potential impact on foot health in obese populations. Full article

Background. Clinicians employ foot morphology assessment to evaluate the functionality of the method and anticipate possible injuries. This study aims to correlate static foot posture and the dynamic barefoot evaluation in a sample of healthy adult participants. Methods. The foot posture was evaluated using the Foot Posture Index-6 (FPI-6) and the dynamics were evaluated through baropodometric examination. Two operators independently assessed the participants’ foot posture through FPI-6, and then a dynamic evaluation was performed by asking them to walk 8 times across a platform. One hundred participants (mean age: 32.15 ± 7.49) were enrolled. Results. The inter-rater agreement between the two assessors was found to be excellent. The majority of the feet belonged to the 0 < FPI < 4 class (32%), followed by the 4 < FPI < 8 (31%) and the FPI > 8 ranges (19.5%). Our “area of contact” analysis showed a significant poor correlation between FPI and total foot, midfoot, and the second metatarsophalangeal joint (MTPJ) (−0.3 < r < 0). Regarding “force” parameters, the analysis showed a poor correlation between the midfoot, hallux, and the second toe (−0.2 < r < 2); finally the “pressure” analysis showed a poor correlation between FPI, the fourth MTPJ, and the second toe (−0.2 < rs < 0.3) and a moderate correlation between the hallux (r = 0.374) and the fifth MTPJ (r = 0.427). Conclusions. This study emphasizes the constrained correlation between static foot posture observation and dynamic barefoot examination. Full article

The Lisfranc joint connects the forefoot to the midfoot. Tarsometatarsal (TMT) arthrodesis is commonly employed for Lisfranc joint injuries; however, there is active discussion regarding the optimal method of fixation for TMT arthrodesis. The purpose of this systematic review is twofold: to assess the stability of various constructs used in TMT arthrodesis and to evaluate joint motion and force distribution in the foot following arthrodesis. The PubMed, CINAHL, MEDLINE, and Web of Science databases were searched for articles evaluating biomechanical and kinetic properties of TMT arthrodesis constructs in accordance with PRISMA guidelines. The preliminary search yielded 367 articles and the final review included 14 articles with 195 cadaveric and 70 synthetic bone constructs. Plantar plates and intramedullary screw fixation at the first TMT joint were consistently found to bear significantly greater loads and resist diastasis more effectively than crossed screws. Furthermore, whole foot and lateral column arthrodesis significantly elevate calcaneocuboid and lateral column pressures. This increase was not observed with isolated fourth or fifth TMT arthrodesis. TMT arthrodesis should aim to avoid the lateral column and fuse as few joints as possible. Overall, plantar plates are an effective construct for first TMT arthrodesis due to their ability to withstand both compressive and tensile forces while maintaining stable alignment of the foot via reinforcement of the transverse arch. Intramedullary fixation devices are an alternative option that provide a high degree of active compression across the joint space while avoiding irritation of surrounding soft tissue structures. Full article

Hallux valgus deformity (HVD) involves subluxation of the first metatarsophalangeal joint. While HVD is primarily considered a forefoot condition, midfoot instability may play a significant role in its development and severity. However, very few studies have placed a heavy emphasis on studying this phenomenon. Therefore, this review had a particular focus on understanding midfoot instability based on weightbearing imaging assessments of the TMT joint. This review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and searched five databases for studies on midfoot instability in HVD patients. The severity of HVD was defined by hallux valgus angle (HVA) and distal metatarsal articular angle (DMAA). Data was extracted, and articles were graded using the Methodological Index for Non-Randomized Studies (MINORS). Of 547 initially retrieved articles, 23 met the inclusion criteria. Patients with HVD showed higher HVA and DMAA on weightbearing radiographs (WBRG) and weightbearing computed tomography (WBCT) compared to healthy individuals. Midfoot instability was assessed through intermetatarsal angle (IMA) and tarsometatarsal angle (TMT angle). Patients with HVD exhibited greater IMA and TMT angles on both WBRG and WBCT. This review highlights the importance of weightbearing imaging assessments for midfoot instability in HVD. IMA and TMT angles can differentiate between healthy individuals and HVD patients, emphasizing the significance of midfoot assessment in understanding HVD pathology. These findings validate the limited evidence thus far in the literature pertaining to consistent midfoot instability in HVD patients and are able to provide ample reasoning for physicians to place a larger emphasis on midfoot imaging when assessing HVD in its entirety. Full article

Microprocessor-controlled prosthetic knees (MPKs) improve the safety and functional capabilities of transfemoral amputees, but there is a lack of information on plantar pressure distribution and effects among individuals who have undergone transfemoral amputation of the sound limb. (1) Background: The aim of this study was to determine possible compensatory mechanisms in gait by evaluating intact extremity foot plantar pressure distribution in young MPK prosthesis users. Twenty-one patients with unilateral transfemoral amputation (TFA) and twenty-four healthy individuals were selected for the study. (2) Methods: The WalkinSense system was used to assess different foot plantar pressure distribution parameters as the participants walked at their chosen walking speed. Plantar pressure peaks and activation percentages in the eight foot regions were measured during the gait cycle. (3) Results: The pressure peaks and activation percentages in the sound limb with TFA patients and healthy subjects were measured, and statistically significant differences between the two groups were identified. The 1-, 2-, 3-, 4-, and 6-point sensor activation percentages significantly increased, whereas the 7- and 8-point sensor activation percentages decreased in the sound limb TFA participants compared with the healthy subjects. Peak plantar pressure sensor points 1, 3, 4, and 6 increased in the TFA sound limb foot in relation to healthy individuals, while they decreased in point 8. (4) Conclusion: In this study, with the use of a microprocessor knee joint TF prosthesis, in the evaluation of the underfoot pressure of intact legs, the maximum pressure point shifted to the forefoot, and it was observed that the forefoot and midfoot were more active during walking compared with the control group. This may indicate that gait compensation and plantar flexion in the sound limb are used more forcefully in the gait cycle. Full article