Using a curved carbon-fiber plate (CFP) in running shoes may offer notable performance benefit over flat plates, yet there is a lack of research exploring the influence of CFP geometry on internal foot loading during running. The objective of this study was to investigate the effects of CFP mechanical characteristics on forefoot biomechanics in terms of plantar pressure, bone stress distribution, and contact force transmission during a simulated impact peak moment in forefoot strike running. We employed a finite element model of the foot-shoe system, wherein various CFP configurations, including three stiffnesses (stiff, stiffer, and stiffest) and two shapes (flat plate (FCFP) and curved plate (CCFP)), were integrated into the shoe sole. Comparing the shoes with no CFP (NCFP) to those with CFP, we consistently observed a reduction in peak forefoot plantar pressure with increasing CFP stiffness. This decrease in pressure was even more notable in a CCFP demonstrating a further reduction in peak pressure ranging from 5.51 to 12.62%, compared to FCFP models. Both FCFP and CCFP designs had a negligible impact on reducing the maximum stress experienced by the 2nd and 3rd metatarsals. However, they greatly influenced the stress distribution in other metatarsal bones. These CFP designs seem to optimize the load transfer pathway, enabling a more uniform force transmission by mainly reducing contact force on the medial columns (the first three rays, measuring 0.333 times body weight for FCFP and 0.335 for CCFP in stiffest condition, compared to 0.373 in NCFP). We concluded that employing a curved CFP in running shoes could be more beneficial from an injury prevention perspective by inducing less peak pressure under the metatarsal heads while not worsening their stress state compared to flat plates.

BACKGROUND: Post-traumatic ankle valgus deformities are relatively rare. Old post-traumatic ankle deformity compounded by abundant scar contracture tissue formation around the joint is a big challenge for orthopedics. Conventional one-stage corrective osteotomy with internal fixation always results in many knotty postoperative complications, such as soft tissue avascular necrosis, implant-related infections, and distinct lower limb discrepancy. Here, we describe a patient with old post-traumatic severe ankle valgus and forefoot supination deformities and obtained satisfactory clinical results following multi-stage surgery using the Ilizarov technique and limited osteotomy. Even more encouraging, any complications of conventional one-stage surgery were successfully avoided through our treatment regimen.
METHODS: A 24-year-old healthy man had post-traumatic 90-degree hindfoot valgus and forefoot supination deformities of the right foot for more than 10 years. The complicated issue was the vast, poorly vascularized scar contracture tissues tightly adhered to the bones of the lateral malleolus and dorsum pedis.
METHODS: Old post-traumatic severe ankle valgus and forefoot supination deformities and scar contracture of soft tissues of the foot and ankle joint.
METHODS: In the first stage, Ilizarov external fixation was used to stretch the scar contracture tissue of the lateral malleolus. In the second stage, limited osteotomy of the tibiotalar joint and progressive closure of the osteotomy site were performed. In the third stage, Chopart joint osteotomy and slow forefoot pronation by external frame were performed.
RESULTS: Our treatment regimen not only guaranteed soft tissue safety, but also avoided infection and obvious lower limb discrepancy. At the 1-year follow-up, the patient acquired aesthetic and functional right foot.
CONCLUSIONS: Although relatively rare, old post-traumatic severe ankle valgus and forefoot supination deformities can be corrected using Ilizarov external fixation technology combined with limited osteotomy. With a well-designed staged operation scheme, soft tissue avascular necrosis, infection of the wound, obvious lower limb discrepancy, and flap grafting can be avoided.

OBJECTIVE: The aim of the soft tissue reconstruction of plantar forefoot should yield weight-bearing function and aesthetic contour, which poses a significant challenge for reconstructive surgeons to provide an appropriate flap according to the \"like for like\" reconstructive principle. Local flaps and pedicled flaps have been described for the reconstruction of small- to medium-sized defects of plantar forefoot and achieved optimal results. However, reconstruction of extensive defects of plantar forefoot is rarely investigated. In this study, we present our experience using the free anterolateral thigh (ALT) flap in the reconstruction of extensive defects of plantar forefoot.
METHODS: Between November 2011 and April 2017, 9 patients were treated for extensive soft tissue defects in the plantar forefoot areas with ALT flaps. The mean age at the time of surgery was 39.3 years (range, 25-64 years).
RESULTS: The follow-up period ranged from 12 to 77 months, with a mean of 31 months. All flaps survived well, and the patients were satisfied with the aesthetic and functional results. The size of the flaps ranged from 63 to 455 cm, with a mean of 197.7 cm. Seven patients with no bony involvement began to gradually weight-bear at 3 weeks postoperatively. During the follow-up time, postoperative ulceration at the reconstructed weight-bearing areas was not encountered.
CONCLUSIONS: The ALT flap is a reliable option for treatment of extensive defects of plantar forefoot, resulting in an optimal functional and aesthetic outcome. Even when a total plantar loss exits, excellent results can be achieved.

BACKGROUND: Distally based peroneal artery perforator-plus fasciocutaneous (DPAPF) flaps are widely used for reconstructing soft-tissue defects of the lower extremity. However, reports on the reconstruction of the defects over the distal forefoot using the DPAPF flaps are scarce. Herein, we describe our experience on the reconstruction of these defects using DPAPF flaps in a considerable sample size.
METHODS: Between February 2005 and August 2019, a total of 56 DPAPF flaps in 56 patients were used to reconstruct soft-tissue defects in the forefoot. In order to reduce the length of fascial pedicle and the total length of the DPAPF flaps, the ankles were fixed in dorsiflexion using a Kirschner wire before designing the flaps. The flaps were elevated by the anterograde-retrograde approach. Patient factors and flap factors were compared between the \"survival\" and \"partial necrosis\" groups.
RESULTS: Overall, 47 flaps had survived completely in one stage. Partial necrosis developed in nine flaps, with only one remnant defect covered using a local flap. By fixing the ankles in dorsiflexion, the length of the fascial pedicle was reduced approximately 2.35 ± 0.58 cm, the total length of the flap was simultaneously shortened by the same amount as the length of the fascial pedicle. The width of the fascia pedicle varied from 3.0 cm to 6.0 cm. The fascial pedicle width > 4 cm was found in 21 flaps. The partial necrosis rate of the DPAPF flaps with the top edge located in the 8th zone was significantly lower than that in the 9th zone (p < 0.05).
CONCLUSIONS: The DPAPF flaps can be effectively used to reconstruct the defects over the distal forefoot because of convenient harvest and reliability. By fixing the ankle in dorsiflexion with Kirschner wire and widening the fascial pedicle appropriately, the top edge and LWR of the flaps will be decreased, and thus the procedures are helpful for the flaps survival.

Although the role of shoe constructions on running injury and performance has been widely investigated, systematic reviews on the shoe construction effects on running biomechanics were rarely reported. Therefore, this review focuses on the relevant research studies examining the biomechanical effect of running shoe constructions on reducing running-related injury and optimising performance. Searches of five databases and Footwear Science from January 1994 to September 2018 for related biomechanical studies which investigated running footwear constructions yielded a total of 1260 articles. After duplications were removed and exclusion criteria applied to the titles, abstracts and full text, 63 studies remained and categorised into following constructions: (a) shoe lace, (b) midsole, (c) heel flare, (d) heel-toe drop, (e) minimalist shoes, (f) Masai Barefoot Technologies, (g) heel cup, (h) upper, and (i) bending stiffness. Some running shoe constructions positively affect athletic performance-related and injury-related variables: 1) increasing the stiffness of running shoes at the optimal range can benefit performance-related variables; 2) softer midsoles can reduce impact forces and loading rates; 3) thicker midsoles can provide better cushioning effects and attenuate shock during impacts but may also decrease plantar sensations of a foot; 4) minimalist shoes can improve running economy and increase the cross-sectional area and stiffness of Achilles tendon but it would increase the metatarsophalangeal and ankle joint loading compared to the conventional shoes. While shoe constructions can effectively influence running biomechanics, research on some constructions including shoe lace, heel flare, heel-toe drop, Masai Barefoot Technologies, heel cup, and upper requires further investigation before a viable scientific guideline can be made. Future research is also needed to develop standard testing protocols to determine the optimal stiffness, thickness, and heel-toe drop of running shoes to optimise performance-related variables and prevent running-related injuries.

BACKGROUND: There has long been a consensus that shortening of the first metatarsal during hallux valgus reconstruction could lead to postoperative transfer metatarsalgia. However, appropriate shortening is sometimes beneficial for correcting severe deformities or relieving stiff joints. This study is to investigate, from the biomechanical perspective, whether and how much shortening of the first metatarsal could be allowed.
METHODS: A finite element model of the human foot simulating the push-off phase of the gait was established. Progressive shortening of the first metatarsal from 2 to 8 mm at an increment of 2 mm were sequentially applied to the model, and the corresponding changes in forefoot loading pattern during push-off phase, especially the loading ratio at the central rays, was calculated. The effect of depressing the first metatarsal head was also investigated.
RESULTS: With increasing shortening level of the first metatarsal, the plantar pressure of the first ray decreased, while that of the lateral rays continued to rise. When the shortening reaches 6 mm, the load ratio of the central rays exceeds a critical threshold of 55%, which was considered risky; but it could still be manipulated to normal if the distal end of the first metatarsal displaced to the plantar side by 3 mm.
CONCLUSIONS: During the first metatarsal osteotomy, a maximum of 6 mm shortening length is considered to be within the safe range. Whenever a higher level of shortening is necessary, pushing down the distal metatarsal segment could be a compensatory procedure to maintain normal plantar force distributions.

Forefoot defects caused by accidents are very common, but their reconstruction remains a substantial challenge for plastic surgeons. The purpose of this study is to determine the anatomical structure of the first metatarsal proximal perforator-based flap and to propose its clinical application. The study was divided into two parts: an anatomical study and a clinical application. Thirty preserved lower limbs injected with red latex were chosen for observation, and the following were recorded: the course and distribution of the medialis dorsalis pedis cutaneous nerve; the origin, course, branching and distribution of the first metatarsal proximal perforator; and the communication of the perforator and the dorsal medial vessels. Clinically, six cases of forefoot skin defects were reconstructed with the first metatarsal proximal perforator-based neurocutaneous vascular flap. The medialis dorsalis pedis cutaneous nerve mainly arose from the medial branch of the superficial peroneal nerve and proceeded forward for a distance of 2.5 ± 0.4 cm under the surface of the inferior extensor retinaculum; then, the nerve divided into the medial dorsal branch and the first and second dorsal metatarsal branches. The first metatarsal proximal perforator-based neurocutaneous vessels were multisegmented and multisourced, and the first branch was closely related to the operative procedure. In terms of the clinical application, all flaps of the six cases survived completely with good appearance, texture and elasticity. The first metatarsal proximal perforators present as constant. The first metatarsal proximal perforator-based neurocutaneous vascular flap may become a useful supplemental material for the reconstruction of forefoot defects. Clin. Anat., 33:653-660, 2020. © 2019 Wiley Periodicals, Inc.

Soft tissue defects of the forefoot represent a challenging surgical modality to reconstructive microsurgeons. This study describes the anatomical basis and design of the perforator-based intermediate dorsal pedal neurocutaneous vascular flap. Thirty fresh human lower limb specimens were injected with red latex and used for dissection of the dorsal vascular and neural anatomy of the foot. The direction and distribution of the intermediate dorsal cutaneous nerve and the vascular anatomy of the third dorsal artery of the plantar arch, along with the intermediate dorsal neurocutaneous nutrient vessels, were mapped. A simulated flap elevation procedure was performed on one fresh cadaver specimen. A clinical series of five cases is presented to demonstrate the feasibility of using the perforator-based intermediate dorsal pedal neurocutaneous vascular flap to reconstruct soft-tissue defects of the forefoot. The intermediate dorsal cutaneous nerve usually originates from the lateral branch of the superficial peroneal nerve. Crossing the surface of the cruciate ligament, it descends distally to the proximal part of the fourth intermetatarsal space and divides into the third and fourth dorsal metatarsal branches. The intermediate dorsal cutaneous neural nutrient vessels, which are multi-segmental and polyphyletic, offer innervation to the skin paddle of the flap elevated on the basis of the third dorsal perforator of the plantar arch. This perforator occupies a relatively constant position in the proximal part of the intermetatarsal space. It sends multiple tiny branches toward the intermediate dorsal cutaneous neural or paraneural nutrient vessel chain. In terms of clinical application, all flaps survived completely; one patient had partial loss of the skin graft. The design and anatomical basis of the intermediate dorsal pedal neurocutaneous vascular flap based on the third dorsal perforator of the plantar arch is a reliable reconstructive option for reconstructing small soft tissue defects in the forefoot. Clin. Anat. 31:1077-1084, 2018. © 2018 Wiley Periodicals, Inc.

The authors aimed to investigate female balance or stability control with comparative analysis of the center of pressure trajectory and plantar pressure distribution with different high-heeled shoes while standing on a dynamic surface with multidirectional perturbations. College females with at least 2 years\' history of wearing high-heel shoes voluntarily participated in the test with a Novel Pedar insole (Novel, GmBH, Munich, Germany. With heels height increasing, the pressure time integral obviously transfer to the medial forefoot region, with center of pressure trajectory medially deviated significantly, either under anteroposterior or mediolateral perturbations. The passive plantarflexion position of ankle incurred by high heel increased the range of motion in the frontal plane but decreased ankle stability, thus increasing the challenge of body balance maintenance.

In the present study we investigated the effects of different durations of using high-heeled shoes on plantar pressure and gait. A questionnaire survey and dynamic plantar pressure measurements were performed in 20 control females and 117 females who had worn high-heeled shoes for a long time. According to the duration of using high-heeled shoes (as specified in the questionnaire), subjects were divided into a control group and five groups with different durations of use (i.e. <2years, 2-5years, 6-10years, 11-20years and >20years). Parameters, including peak pressure, impulse and pressure duration, in different plantar regions were measured with the Footscan pressure plate. The 2-5years group had smaller midfoot contact areas for both feet and higher subtalar joint mobility, while the 6-10years group had larger midfoot contact areas for both feet and prolonged foot flat phase during gait. The peak pressure and impulse under the second and fourth metatarsus were increased with the prolonged wearing of high-heeled shoes, and the pressure and impulse under the midfoot were substantially reduced in the 2-5years group. The findings suggest that long-term use of high-heeled shoes can induce changes in arch morphology: the longitudinal arch tends to be elevated within 2-5years; the longitudinal arch tends to be flattened within 6-10years; and the forefoot latitudinal arch tends to collapse in more than 20years.