Search Results (5)

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

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

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

The lateral wedge insole (LWI) is a typical orthopedic treatment for medial knee osteoarthritis pain, chronic ankle instability, and peroneal tendon disorders. It is still unknown what the effects are in the most important joints of the foot when using LWIs as a treatment for knee and ankle pathologies. Objectives: The aim of this study was to determine the influence of LWIs on the position of the midfoot and rearfoot joints by measuring the changes using a tracking device. Methods: The study was carried out with a total of 69 subjects. Movement measurements for the midfoot were made on the navicular bone, and for the rearfoot on the calcaneus bone. The Polhemus system was used, with two motion sensors fixed to each bone. Subjects were compared by having them use LWIs versus being barefoot. Results: There were statistically significant differences in the varus movement when wearing a 4 mm LWI (1.23 ± 2.08°, p < 0.001) versus the barefoot condition (0.35 ± 0.95°), and in the plantarflexion movement when wearing a 4 mm LWI (3.02 ± 4.58°, p < 0.001) versus the barefoot condition (0.68 ± 1.34°), in the midfoot. There were also statistically significant differences in the valgus movement when wearing a 7 mm LWI (1.74 ± 2.61°, p < 0.001) versus the barefoot condition (0.40 ± 0.90°), and in the plantar flexion movement when wearing a 4 mm LWI (2.88 ± 4.31°, p < 0.001) versus the barefoot condition (0.35 ± 0.90°), in the rearfoot. Conclusions: In the navicular bone, a varus, an abduction, and plantar flexion movements were generated. In the calcaneus, a valgus, an adduction, and plantar flexion movements were generated with the use of LWIs. Full article

Background: Foot–ankle motion is affected by chronic ankle instability (CAI) in terms of altered kinematics. This study focuses on multisegmental foot–ankle motion and joint coupling in barefoot and taped CAI patients during the three subphases of stance at running. Methods: Foot segmental motion data of 12 controls and 15 CAI participants during running with a heel strike pattern were collected through gait analysis. CAI participants performed running trials in three conditions: barefoot running, and running with high-dye and low-dye taping. Dependent variables were the range of motion (RoM) occurring at the different inter-segment angles as well as the cross-correlation coefficients between predetermined segments. Results: There were no significant RoM differences for barefoot running between CAI patients and controls. In taped conditions, the first two subphases only showed RoM changes at the midfoot without apparent RoM reduction compared to the barefoot CAI condition. In the last subphase there was limited RoM reduction at the mid- and rearfoot. Cross-correlation coefficients highlighted a tendency towards weaker joint coupling in the barefoot CAI condition compared to the controls. Joint coupling within the taped CAI conditions did not show optimization compared to the barefoot CAI condition. Conclusions: RoM was not significantly changed for barefoot running between CAI patients and controls. In taped conditions, there was no distinct tendency towards lower mean RoM values due to the mechanical restraints of taping. Joint coupling in CAI patients was not optimized by taping. Full article