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The energy-sparing spring theory of the foot’s arch has become central to interpretations of the foot’s mechanical function and evolution. Using a novel insole technique that restricted compression of the foot’s longitudinal arch, this study provides the first direct evidence that arch compression/recoil during locomotion contributes to lowering energy cost. Restricting arch compression near maximally (~80%) during moderate-speed (2.7 ms −1 ) level running increased metabolic cost by + 6.0% ( p  < 0.001, d  = 0.67; unaffected by foot strike technique). A simple model shows that the metabolic energy saved by the arch is largely explained by the passive-elastic work it supplies that would otherwise be done by active muscle. Both experimental and model data confirm that it is the end-range of arch compression that dictates the energy-saving role of the arch. Restricting arch compression had no effect on the cost of walking or incline running (3°), commensurate with the smaller role of passive-elastic mechanics in these gaits. These findings substantiate the elastic energy-saving role of the longitudinal arch during running and suggest that arch supports used in some footwear and orthotics may increase the cost of running.

Although autografts are considered to be the gold standard treatment for reconstruction of large bone defects resulting from trauma or diseases, donor site morbidity and limited availability restrict their use. Successful bone repair also depends on sufficient vascularization and to address this challenge, novel strategies focus on the development of vascularized biomaterial scaffolds. This pilot study aimed to investigate the feasibility of regenerating large bone defects in sheep using 3D-printed customized calcium phosphate scaffolds with or without surgical vascularization. Pre-operative computed tomography scans were performed to visualize the metatarsus and vasculature and to fabricate customized scaffolds and surgical guides by 3D printing. Critical-sized segmental defects created in the mid-diaphyseal region of the metatarsus were either left empty or treated with the 3D scaffold alone or in combination with an axial vascular pedicle. Bone regeneration was evaluated 1, 2 and 3 months post-implantation. After 3 months, the untreated defect remained non-bridged while the 3D scaffold guided bone regeneration. The presence of the vascular pedicle further enhanced bone formation. Histology confirmed bone growth inside the porous 3D scaffolds with or without vascular pedicle inclusion. Taken together, this pilot study demonstrated the feasibility of precised pre-surgical planning and reconstruction of large bone defects with 3D-printed personalized scaffolds.

The African terrestrial fossil record has been limited in its contribution to our understanding of both regional and global Cretaceous paleobiogeography, an interval of significant geologic and macroevolutionary change. A common component in Cretaceous African faunas, titanosaurian sauropods diversified into one of the most specious groups of dinosaurs worldwide. Here we describe the new titanosaurian Mnyamawamtuka moyowamkia gen. et sp. nov. from the Mtuka Member of the Galula Formation in southwest Tanzania. The new specimen preserves teeth, elements from all regions of the postcranial axial skeleton, parts of both appendicular girdles, and portions of both limbs including a complete metatarsus. Unique traits of M. moyowamkia include the lack of an interpostzygapophyseal lamina in posterior dorsal vertebrae, pronounced posterolateral expansion of middle caudal centra, and an unusually small sternal plate. Phylogenetic analyses consistently place M. moyowamkia as either a close relative to lithostrotian titanosaurians (e.g., parsimony, uncalibrated Bayesian analyses) or as a lithostrotian and sister taxon to Malawisaurus dixeyi from the nearby Aptian? Dinosaur Beds of Malawi (e.g., tip-dating Bayesian analyses). M. moyowamkia shares a few features with M. dixeyi, including semi-spatulate teeth and a median lamina between the neural canal and interpostzygapophyseal lamina in anterior dorsal vertebrae. Both comparative morphology and phylogenetic analyses support Mnyamawamtuka as a distinct and distant relative to Rukwatitan bisepultus and Shingopana songwensis from the younger Namba Member of the Galula Formation with these results largely congruent with newly constrained ages for the Mtuka Member (Aptian-Cenomanian) and Namba Member (Campanian). Coupled with recent discoveries from the Dahkla Oasis, Egypt (e.g., Mansourasaurus shahinae) and other parts of continental Afro-Arabia, the Tanzania titanosaurians refine perspectives on the development of African terrestrial faunas throughout the Cretaceous-a critical step in understanding non-marine paleobiogeographic patterns of Africa that have remained elusive until the past few years.

In the wake of the quest to break the 2-h marathon barrier, carbon-fiber plates have become commonplace in marathon racing shoes. Despite the controversy surrounding this shoe technology, studies on the effects of increased longitudinal bending stiffness on running economy report mixed results. Here, we provide a comprehensive review of the current literature on midsole bending stiffness and carbon-fiber plates in distance running shoes, focusing on how longitudinal bending stiffness affects running energetics and lower limb mechanics. The current literature reports changes in running economy with increased longitudinal bending stiffness ranging from ~ 3% deterioration to ~ 3% improvement. In some studies, larger improvements have been observed, but often those shoes varied in many aspects, not just longitudinal bending stiffness. Biomechanically, increased longitudinal bending stiffness has the largest impact on metatarsal–phalangeal (MTP) and ankle joint mechanics. Plate location [top loaded (an insole), embedded (in between midsole foam), and bottom loaded (along the bottom of the shoe)] and geometry (flat/curved) affect joint moments and angular velocities at the MTP and ankle joint differently, which partly explains the mixed running economy results. Further research investigating how carbon-fiber plates interact with other footwear features (such as foam and midsole geometry), scaling of those with shoe size, body mass, and strike pattern, and comparing various plate placements is needed to better understand how longitudinal bending stiffness affects running economy.

A hominin third metatarsal discovered in 2007 in Callao Cave (Northern Luzon, the Philippines) and dated to 67 thousand years ago provided the earliest direct evidence of a human presence in the Philippines. Analysis of this foot bone suggested that it belonged to the genus Homo , but to which species was unclear. Here we report the discovery of twelve additional hominin elements that represent at least three individuals that were found in the same stratigraphic layer of Callao Cave as the previously discovered metatarsal. These specimens display a combination of primitive and derived morphological features that is different from the combination of features found in other species in the genus Homo (including Homo floresiensis and Homo sapiens ) and warrants their attribution to a new species, which we name Homo luzonensis . The presence of another and previously unknown hominin species east of the Wallace Line during the Late Pleistocene epoch underscores the importance of island Southeast Asia in the evolution of the genus Homo . Homo luzonensis , a new species of Homo from the Callao Cave in the Philippines from the Late Pleistocene epoch, is described.

Background Typical foot deformity patterns of patients with rheumatoid arthritis (RA) include hallux valgus, claw toes, splay foot, flat foot, and hindfoot valgus deformities. However, some patients present deformities that are different from a typical pattern, such as metatarsus primus elevatus, described as dorsal elevation of the first metatarsal in relation to the lesser metatarsals. We speculated that metatarsus primus elevatus might be associated with calcaneal inclination and hindfoot varus alignment; however, studies on the association of hindfoot alignment with metatarsus primus elevatus in patients with RA are limited. Objective To elucidate the impact of hindfoot coronal and sagittal alignment on metatarsus primus elevatus in patients with RA. Methods We performed a retrospective analysis of weight-bearing anteroposterior and lateral radiographs of 58 patients (112 feet) with rheumatoid foot deformities who underwent surgery. The degree of metatarsus primus elevatus (dMPE) was assessed based on the distance between the dorsal cortical bones of the first and second metatarsals, as measured on lateral radiographs. The intermetatarsal angle between the first and second metatarsals (M1M2), calcaneal pitch, and the naviculocuboid (N/C) overlap ratio were assessed. Patients were divided into four subgroups representing dMPE quartiles (Q1–Q4) as closely as possible. Analysis of covariance was used to calculate the adjusted means of the radiographic parameters. Logistic regression was used to assess the association between clinical and radiographic parameters and the risk of being in the highest dMPE quartile (i.e., Q4). Results The median dMPE in patients with RA was 2.0 mm (interquartile range, 0.2–5.4 mm). Analysis after adjusting for sex, age, body mass index, and disease duration revealed that the M1M2 angle and N/C overlap ratio in the Q4 subgroup were significantly smaller than those in the Q1 subgroup ( p  < 0.01 for both parameters). Only the N/C overlap ratio showed a significant inverse association with the risk of being in Q4 (adjusted odds ratio: 0.94, 95% confidence interval: 0.91–0.97). Conclusion A subset of patients with RA exhibits metatarsus primus elevatus, which is associated with hindfoot alignment. Recognizing this less common deformity pattern is important when planning treatment strategies for the rheumatoid foot.

Background Metatarsus adductus is the most common congenital foot deformity in newborns. It involves adduction of the metatarsals at the Lisfranc joint. A systematic literature review was conducted to investigate the following question: What tools are used to identify and quantify metatarsus adductus and how reliable, valid and responsive are they? Methods The following electronic databases were searched for studies describing tools for the identification and quantification of metatarsus adductus in adults and children published from inception to June 2016: Ovid MEDLINE, Embase, CINAHL, Scopus, Web of Science and AMED. Two researchers initially searched all articles by screening titles and abstracts. If there was any doubt as to an article’s eligibility, the full text paper was retrieved. Reference lists and citations of all retained studies were examined in an attempt to locate further studies. Articles were excluded if they were not in English or described other congenital foot conditions that did not include metatarsus adductus. Studies included in the review reporting measurement properties of measurement tools were critically appraised using the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) critical appraisal tool. Results There were 282 articles screened by title and abstract and 28 articles screened from full text. Fifteen articles were included and nine had data that were extractable for appraisal using the COSMIN critical appraisal tool. Techniques to measure metatarsus adductus included the heel bisector method, photocopies, ultrasound, footprints, dynamic foot pressure and radiographs. There was a paucity of quality data reporting the reliability, validity or responsiveness for measuring metatarsus adductus. Several radiographic angles showed good reliability (intraclass correlation (ICC) – 0.84, 0.97) in adults during pre-operative planning. Conclusion There have been multiple assessment techniques proposed for quantification of metatarsus adductus, but there is paucity of reliability, validity or responsiveness to measurement data about these techniques, especially in relation to the paediatric population. Further consideration of measurement testing is required to determine if the most common non-radiographic measures of metatarsus adductus are acceptable for clinical use.

In this report of two randomized trials, patients with type 2 diabetes at risk for cardiovascular disease received the sodium–glucose cotransporter 2 inhibitor canagliflozin or placebo and were followed for 188 weeks. Canagliflozin reduced the risk of cardiovascular events.

BackgroundElevated first metatarsal, Metatarsus primus elevatus (MPE), has been a topic of controversy. Recent studies have supported a significantly elevated first metatarsal in hallux rigidus on weight-bearing radiographs (WBR). However, conventional radiographs have limitations for accurate measurement. Our objective was to comparatively assess MPE and other variables which can affect the spatial relationship of the forefoot in the HR group compared to controls using weight-bearing CT (WBCT).MethodsIn this single-center, retrospective, case–control study, 25 patients (30 feet) with symptomatic HR and 30 controls were selected. WBCT parameters were measured by two independent investigators. Inter-observer reliabilities were assessed using intra-class correlation coefficients (ICCs). MPE was evaluated by measuring the direct distance between 1st and 2nd metatarsals. Independent t tests were performed to compare the two groups. A threshold of MPE to diagnose HR was calculated using the Receiver Operating Characteristic (ROC) curve.ResultsHR groups had increased hallux valgus angle (HVA) (8.52° in control vs 11.98° in HR) and MPE (2.92 vs 5.09 mm), decreased 1st metatarsal declination angle (21.09° vs 19.07°) 1st/2nd metatarsal declination ratio (87.45 vs 79.71) indicating elevated first metatarsal compared to controls. Dorsal translation of the first metatarsal at the first tarsometatarsal joint was observed in 21 (70%) patients of the HR group when defined as a step-off or discontinuation of the curvature along the first TMT joint. The threshold of MPE for diagnosis of HR was 4.19 mm with 77% sensitivity and 77% specificity.ConclusionOur results confirmed a significantly elevated first metatarsal in the HR group compared to controls on WBCT. A MPE greater than 4.19 mm was found to be diagnostic for symptomatic HR. Significant number of patients in the HR group (70%) had dorsal translation of the first metatarsal at the first TMT joint which can contribute to increased MPE.Clinical relevanceThe present study demonstrated significantly increased MPE in HR on WBCT and MPE greater than 4.19 mm on WBCT can be used as a diagnostic threshold for HR.

Metallic implants with a low effective modulus can provide early load-bearing and reduce stress shielding, which is favorable for increasing in vivo life-span. In this research, porous Ti6Al4V scaffolds with three pore sizes (300~400, 400~500 and 500~700 μm) were manufactured by Electron Beam Melting, with an elastic modulus range of 3.7 to 1.7 GPa. Cytocompatibility in vitro and osseointegration ability in vivo of scaffolds were assessed. hBMSCs numbers increased on all porous scaffolds over time. The group with intended pore sizes of 300 to 400 μm was significantly higher than that of the other two porous scaffolds at days 5 and 7. This group also had higher ALP activity at day 7 in osteogenic differentiation experiment. The scaffold with pore size of 300 to 400 μm was implanted into a 30-mm segmental defect of goat metatarsus. In vivo evaluations indicated that the depth of bone ingrowth increased over time and no implant dislocation occurred during the experiment. Based on its better cytocompatibility and favorable bone ingrowth, the present data showed the capability of the additive manufactured porous Ti6Al4V scaffold with an intended pore size of 300 to 400 μm for large segmental bone defects.