Search Results (26)

Background: Hallux rigidus (HR) is a common forefoot disorder, and surgical treatment is typically guided by the severity of the condition, as defined by the Coughlin and Shurnas four-grade classification. This study aimed to compare clinical and functional outcomes in patients undergoing first metatarsophalangeal joint arthrodesis (FMTPJA) with or without the use of an interfragmentary (IF) screw in addition to a dorsal plate. Methods: We retrospectively evaluated a cohort of patients who underwent surgery with a FMTPJA, dividing patients in two groups: patients who underwent FMTPJA through dorsal plate associated with an interfragmentary screw (WIS group) and patients who underwent FMTPJA through dorsal plate without an interfragmentary screw (WOIS group). The primary outcomes were analyzed using the FAAM score and FAAM sport score. Secondary outcomes included VAS, patient satisfaction, recovery time to return to sports, and the level of postoperative sports activity compared to preoperative levels. Results: In paired analyses, the WOIS group showed statistically significant improvements in both the FAAM and FAAM sport scores (p = 0.01). In contrast, the WIS group showed significant improvement only in the FAAM sport score (p = 0.01), while the FAAM score did not reach statistical significance (p = 0.42). Multivariate analysis revealed that a higher preoperative FAAM score predicted a higher postoperative FAAM score (p = 0.75), while the use of an IF screw was associated with a lower expected postoperative FAAM score (p = 0.25). Increased BMI and older age were significantly associated with lower postoperative FAAM scores. Conclusions: Both surgical techniques led to significant clinical improvements. However, patients in the WOIS group showed a trend toward faster recovery and higher postoperative sports activity levels, particularly in the athletic population. Although no statistically significant differences were found between groups overall, these findings suggest potential benefits of avoiding an IF screw in selected patients. Further prospective studies are warranted to better delineate the clinical impact of screw usage in FMTPJA. Full article

Background/Objectives: Semi-active prosthetic feet present a promising solution that enhances adaptability while maintaining modest size, weight, and cost. We propose a semi-active Two-Keel Variable-Stiffness Foot (VSF-2K), the first prosthetic foot where both the hindfoot and forefoot stiffness can be independently and actively modulated. We present a model-based analysis of the effects of different VSF-2K settings on prosthesis characteristics and gait metrics. Methods: The study introduces a simulation model for the VSF-2K: (1) one sub-model to optimize the design of the keels of VSF-2K to maximize compliance, (2) another sub-model to simulate the stance phase of walking with different stiffness setting pairs and ankle alignment angles (dorsiflexion/plantarflexion), and (3) a third sub-model to simulate the keel stiffness of the hindfoot and forefoot keels comparably to typical mechanical testing. We quantitatively analyze how the VSF-2K’s hindfoot and forefoot stiffness settings and ankle alignments affect gait metrics: Roll-over Shape ($ROS$), Effective Foot Length Ratio ($EFLR$), and Dynamic Mean Ankle Moment Arm ($DMAMA$). We also introduce an Equally Spaced Resampling Algorithm (ESRA) to address the unequal-weight issue in the least-squares circle fit of the Roll-over Shape. Results: We show that the optimal-designed VSF-2K successfully achieves controlled stiffness that approximates the stiffness range observed in prior studies of commercial prostheses. Our findings suggest that stiffness modulation significantly affects gait metrics, and it can mimic or counteract ankle angle adjustments, enabling adaptation to sloped terrain. We show that $DMAMA$ is the most promising metric for use as a control parameter in semi-active or variable-stiffness prosthetic feet. We identify the limitations in $ROS$ and $EFLR$, including their nonmonotonic relationship with hindfoot/forefoot stiffness, insensitivity to hindfoot stiffness, and inconsistent trends across ankle alignments. We also validate that the angular stiffness of a two-independent-keel prosthetic foot can be predicted using either keel stiffness from our model or from a standardized test. Conclusions: These findings show that semi-active variation of hindfoot and forefoot stiffness based on single-stride metrics such as $DMAMA$ is a promising control approach to enabling prostheses to adapt to a variety of terrain and alignment challenges. Full article

Background: The role of tibialis anterior activity in sit-to-stand motion is unclear. We hypothesized that contraction of the tibialis anterior would slightly lift the forefoot and shift the center of pressure backward. Objectives: The objective of this study was to clarify this movement and its role in tibialis anterior activity. Methods: Ten healthy adults performed the sit-to-stand motion. Cross-correlation coefficients among tibialis anterior activity, shank inclination angle, and center of pressure were calculated. Whole-body joint moments were simulated when the center of pressure varied within the foot. The angle of the ground reaction force during seat-off was calculated. Results: The center of pressure moved backward in all trials for all participants. The mean lag time for peak cross-correlation coefficients between the tibialis anterior and shank tilt and between the tibialis anterior and center of pressure was 0.37 and 0.13 s, respectively. Simulating the center of pressure forward resulted in greater whole-body joint moments than those measured (mean 1.88 times). The ground reaction forces were nearly perpendicular to the floor. Conclusions: From the perspective of temporal synchrony, tibialis anterior activity significantly contributed to the backward shift of the center of pressure. The center of pressure shift minimized the force exerted by the entire body. Full article

Background: Hallux valgus (HV) is one of the most common foot deformities and negatively impacts plantar support. The abductor hallucis (AH) is the most important muscle in the etiopathogenesis of hallux valgus, but the effectiveness of its rehabilitation clashes with the difficulty of identifying the most suitable exercises to activate it. Therefore, the aim of this study was to compare four different therapeutic exercises in the activation of AH in these patients. Methods: In this observational case–control study, 48 patients suffering from hallux valgus of moderate/severe grade, according to traditional radiographic classification and the Manchester scale, were divided into two groups: the case group underwent a monthly rehabilitation protocol for their foot deformity, whereas the control group was only evaluated without any intervention. The exercises were as follows: Toe Spread Out (TSO), Short Foot (SF), Forefoot Adduction (FA), and Flexion of the Metatarsophalanges (FM). Both groups were analyzed at baseline and 1 month later (at the end of rehabilitation for the case group) while performing the four mentioned exercises using a surface electromyograph (sEMG) to record the muscle activity of AH in terms of Root Mean Square (RMS) and Maximum Voluntary Contraction (MVC). Results: FA was the only exercise to determine a statistically significant improvement in AH at the end of the rehabilitation cycle, both in terms of RMS (p = 0.015) and in terms of MVC (p < 0.0001), whereas the other exercises did not produce any change in muscle activity in the comparison between times and groups or in the related interaction. Conclusions: FA seems to be the best exercise to activate and train AH, so rehabilitation programs for patients suffering from hallux valgus should consider this exercise as the starting point for improving plantar support, always considering the specific characteristics of HV. Further studies are needed to deepen the effectiveness of this exercise, with the aim of implementing rehabilitation strategies and rethinking traditional HV therapies, which are currently predominantly surgical. Full article

Background: Running is a popular physical activity known for its health benefits but also for a high incidence of lower-limb injuries. This study examined the effects of three biomechanical interventions—cadence adjustments, footwear modifications, and foot orthoses—on plantar pressure distribution and spatiotemporal running parameters. Methods: A quasi-experimental, repeated-measures design was conducted with 23 healthy recreational runners (mean age 25, mean BMI 22.5) who ran at least twice per week. Five conditions were tested: baseline (C0), increased cadence (C1), orthoses (C2), low-drop footwear (C3), and a combination of these (C4). Data were collected on a Zebris treadmill, focusing on rearfoot contact time, peak forces, and stride length. Results: Increasing cadence (C1) reduced rearfoot impact forces (−81.36 N) and led to a shorter stride (−17 cm). Low-drop footwear (C3) decreased rearfoot contact time (−1.89 ms) and peak force (−72.13 N), while shifting pressure toward the midfoot. Orthoses (C2) effectively redistributed plantar pressures reducing rearfoot peak force (−41.31 N) without changing stride length. The combined intervention (C4) yielded the most pronounced reductions in peak forces across the rearfoot (−183.18 N) and forefoot (−139.09 N) and increased midfoot contact time (+5.07 ms). Conclusions: Increasing cadence and low-drop footwear significantly reduced impact forces, improving running efficiency. Orthoses effectively redistributed plantar pressures, supporting individualized injury prevention strategies. These findings suggest that combining cadence adjustments, footwear modifications, and orthoses could enhance injury prevention and running efficiency for recreational runners. Full article

Background/Objectives: Post-stroke hemiparetic gait often presents with asymmetric patterns to compensate for stability deficits. This study examines gait differences in chronic stroke patients with spastic hemiparesis based on initial foot contact type—forefoot versus rearfoot. Methods: Thirty-four independently walking spastic hemiparetic patients were retrospectively analyzed. Using 3D gait analysis, patients were categorized by initial contact type. Spatiotemporal descriptors, joint kinematics, kinetics, and EMG patterns were compared across groups. Results: Patients with rearfoot initial contact (G1) showed higher cadence, longer single-limb support time and shorter stride times than those with forefoot contact (G0). G1 patients also demonstrated greater knee flexion during stance, enhancing stability. Additionally, G1 patients with abnormal lateral gastrocnemius activation in the swing phase showed increased ankle power at the end of the stance phase. Conclusions: In post-stroke spastic hemiparetic patients, the type of initial foot contact—forefoot or rearfoot—appears to influence gait characteristics, with rearfoot contact associated with a trend toward improved gait parameters, such as increased cadence and longer single-limb support. Full article

Background: Advanced footwear technology (AFT) has gained popularity among non-elite runners due to its potential benefits in training and competition. This study investigated the training practices and reported outcomes in non-elite runners using AFT. Methods: A cross-sectional observational study was conducted with 61 non-elite runners competing in distances ranging from 5 km to marathons. The survey collected data on demographics, training parameters, footwear usage, perceived changes in running mechanics, and self-reported injuries. Results: The results revealed a significant positive correlation (R = 0.6, p < 0.0001) between years of AFT use and weekly training volume, indicating that more experienced runners are likely to incorporate AFT consistently into their routines. Conversely, a significant negative correlation (R = −0.5, p < 0.0001) was found between training volume and the number of weekly sessions using AFT, suggesting a selective approach to footwear use. Participants reported biomechanical changes, such as increased forefoot support (49%) and higher calf muscle activation (44%), alongside a 16% self-reported injury rate, predominantly affecting the calves. Conclusions: These findings highlight the importance of proper guidance and gradual adaptation to maximize the benefits of AFT while minimizing injury risks. Future research should explore the long-term impact of AFT on performance and injury prevention through longitudinal studies. 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

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

Equinus and equinovarus foot deviations (EVFD) are the most frequent lower limb acquired deformities in stroke survivors. We analysed the contribution that the tibialis anterior (TA), extensor digitorum longus (EDL) and plantarflexor muscles play in EVFD via a biomechanical musculoskeletal model of the ankle–foot complex. Our model was composed of 28 bones (connected by either revolute joints or bone surface contacts), 15 ligaments (modelled as non-linear springs), and 10 muscles, modelled as force actuators. Different combinations of muscle contractions were also simulated. Our results demonstrate that, compared to the condition when the foot is suspended off the ground, the contraction of the TA alone produces dorsiflexion (from −18° to 0°) and a greater supination/inversion (from 12° to 30°). The EDL alone produces dorsiflexion (from −18° to −6°), forefoot pronation (25°) and calcaneal eversion (5.6°). Only TA and EDL synergistic action can lead the foot to dorsiflexion suitable for most daily life activities (≥20°) without any deviation in the frontal plane. When pathological contractures of the plantarflexor muscles were simulated, foot deformities reproducing EVFD were obtained. These results can be relevant for clinical applications, highlighting the importance of EDL assessment, which may help to design appropriate functional surgery and plan targeted rehabilitation treatments. Full article

The association between craniofacial muscles and postural control is well-known because of numerous anatomical connections. However, there are a few conflicting studies that correlated the activity of the masticatory muscles with the distribution of body weight pressure on the feet, which can strongly influence balance. Therefore, the purpose of our study was to evaluate the association between the masseter and temporalis muscle activity and foot pressure distribution. Fifty-two women were recruited, and baropodometric and EMG analyses of the masseter and temporalis baseline activities were analyzed. An ipsilateral association was found between the right temporal muscle activity and the right rearfoot load (r = 0.29, p < 0.05) and right forefoot load (r = −0.29; p < 0.05), as well as the percentage of muscle activation of the right masseter muscles with the percentage of pressure on the right forefoot (r = 0.31, p < 0.05) and right rearfoot (r = −0.31, p < 0.05). While further studies are needed, an ipsilateral association was found between masticatory muscles and foot pressure distribution. Full article

Accelerometry is becoming a popular method to access human movement in outdoor conditions. Running smartwatches may acquire chest accelerometry through a chest strap, but little is known about whether the data from these chest straps can provide indirect access to changes in vertical impact properties that define rearfoot or forefoot strike. This study assessed whether the data from a fitness smartwatch and chest strap containing a tri-axial accelerometer (FS) is sensible to detect changes in running style. Twenty-eight participants performed 95 m running bouts at ~3 m/s in two conditions: normal running and running while actively reducing impact sounds (silent running). The FS acquired running cadence, ground contact time (GCT), stride length, trunk vertical oscillation (TVO), and heart rate. Moreover, a tri-axial accelerometer attached to the right shank provided peak vertical tibia acceleration (PK_ACC). The running parameters extracted from the FS and PK_ACC variables were compared between normal and silent running. Moreover, the association between PK_ACC and smartwatch running parameters was accessed using Pearson correlations. There was a 13 ± 19% reduction in PK_ACC (p < 0.005), and a 5 ± 10% increase in TVO from normal to silent running (p < 0.01). Moreover, there were slight reductions (~2 ± 2%) in cadence and GCT when silently running (p < 0.05). However, there were no significant associations between PK_ACC and the variables extracted from the FS (r < 0.1, p > 0.05). Therefore, our results suggest that biomechanical variables extracted from FS have limited sensitivity to detect changes in running technique. Moreover, the biomechanical variables from the FS cannot be associated with lower limb vertical loading. Full article

Official guidelines state that suitable physical activity is recommended for patients with diabetes mellitus. However, since walking at a rapid pace could be associated with increased plantar pressure and potential foot pain, the footwear condition is particularly important for optimal foot protection in order to reduce the risk of tissue injury and ulceration of diabetic patients. This study aims to analyze foot deformation and plantar pressure distribution at three different walking speeds (slow, normal, and fast walking) in dynamic situations. The dynamic foot shape of 19 female diabetic patients at three walking speeds is obtained by using a novel 4D foot scanning system. Their plantar pressure distributions at the three walking speeds are also measured by using the Pedar in-shoe system. The pressure changes in the toes, metatarsal heads, medial and lateral midfoot, and heel areas are systematically investigated. Although a faster walking speed shows slightly larger foot measurements than the two other walking speeds, the difference is insignificant. The foot measurement changes at the forefoot and heel areas, such as the toe angles and heel width, are found to increase more readily than the measurements at the midfoot. The mean peak plantar pressure shows a significant increase at a faster walking speed with the exception of the midfoot, especially at the forefoot and heel areas. However, the pressure time integral decreases for all of the foot regions with an increase in walking speed. Suitable offloading devices are essential for diabetic patients, particularly during brisk walking. Design features such as medial arch support, wide toe box, and suitable insole material for specific area of the foot (such as polyurethane for forefoot area and ethylene-vinyl acetate for heel area) are essential for diabetic insole/footwear to provide optimal fit and offloading. The findings contribute to enhancing the understanding of foot shape deformation and plantar pressure changes during dynamic situations, thus facilitating the design of footwear/insoles with optimal fit, wear comfort, and foot protection for diabetic patients. Full article

The sole is a key component of the interaction between foot and ground in daily activities, and its cushioning performance plays a crucial role in protecting the joints of lower limbs from impact injuries. Based on the excellent cushioning performance of the ostrich foot and inspired by the structure and material assembly features of the ostrich foot’s metatarsophalangeal skeletal–tendon and the ostrich toe pad–fascia, a functional bionic cushioning unit for the midsole (including the forefoot and heel) area of athletic shoes was designed using engineering bionic technology. The bionic cushioning unit was then processed based on the bionic design model, and the shoe soles were tested with six impact energies ranging from 3.3 J to 11.6 J for a drop hammer impact and compared with the conventional control sole of the same size. The results indicated that the bionic forefoot area absorbed 9.83–34.95% more impact and 10.65–43.84% more energy than the conventional control forefoot area, while the bionic heel area absorbed 26.34–44.29% more impact and 28.1–51.29% more energy than the conventional control heel area when the controlled impact energy varied from 3.3 J to 11.6 J. The cushioning performance of the bionic cushioning sole was generally better than that of the conventional control sole, and the cushioning and energy-absorption performances of the heel bionic cushioning unit were better than those of the forefoot bionic cushioning unit. This study provides innovative reference and research ideas for the design and development of sports shoes with good cushioning performance. Full article

This study investigates the effects of fatigue on the process of walking in young adults using the developed clog-integrated sensor system. The developed sensor can simultaneously measure the forefoot activity (FA) and minimum toe clearance (MTC). The FA was evaluated through the change in the contact area captured by a camera using a method based on a light conductive plate. The MTC was derived from the distance between the bottom surface of the clog and ground obtained using a time of flight (TOF) sensor, and the clog posture was obtained using an acceleration sensor. The induced fatigue was achieved by walking on a treadmill at the fastest walking speed. We evaluated the FA and MTC before and after fatigue in both feet for 14 participants. The effects of fatigue manifested in either the FA or MTC of either foot when the results were evaluated by considering the participants individually, although individual variances in the effects of fatigue were observed. In the dominant foot, a significant increase in either the FA or MTC was observed in 13 of the 14 participants. The mean MTC in the dominant foot increased significantly (p = 0.038) when the results were evaluated by considering the participants as a group. Full article