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Background: Plano-valgus is a common alteration of the paediatric foot, characterized by valgus hindfoot, foot pronation and drop of the medial longitudinal arch. Despite their importance in the diagnosis and classification of plano-valgus foot condition, little information is available on functional alterations of the major joints spanning the medial longitudinal arch - i.e. midtarsal and tarso-metatarsal. Aim of the study was to provide objective description of the alterations in plano-valgus midfoot joints with respect to those in an age-matched normally-developed feet population., Methods: Twenty adolescents (13.3 ± 0.8 years) with bilateral plano-valgus feet underwent clinical examination and were gait-analysed via a validated 4-segment foot model. This allowed to measure static foot posture, kinematics of the main foot joints, and medial longitudinal arch deformation during walking at comfortable speed. Range of motion and temporal profiles of joint rotations were compared to those from a control population of age-matched adolescents with normally-developed feet., Results: The plano-valgus midtarsal joint was more dorsiflexed, everted and abducted than that in the control group, and showed reduced sagittal-plane RoM (plano-valgus = 15.9 degrees; control = 22.2 degrees; P  <  0.01). The tarso-metarsal joint was more plantarflexed and adducted, and showed larger frontal-plane RoM. The MLA showed larger RoM and was lower throughout the stance phase of the gait cycle., Conclusion: Significant postural and kinematic alterations are present at the midtarsal and tarso-metarsal joints of adolescents with plano-valgus feet. Objective identification and quantification of plano-valgus foot alterations, via non-invasive gait-analysis, is relevant to improving the diagnosis of this condition and to evaluating the effect of conservative treatments and of surgical corrections by different techniques., Competing Interests: Acknowledgement of the Hospital’s IRB was granted (protocol n° 7/17) and parents’ informed consent was obtained for all children recruited in the study.Parents’ consent to publish was granted.The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Background: The validity of predicting foot pronation occurring mainly at the midfoot by surrogate measures from the rearfoot, like eversion excursion, is limited. The dynamic navicular mobility in terms of vertical navicular drop ( dNDrop ) and medial navicular drift ( dNDrift ) may be regarded as meaningful clinical indicators to represent overall foot function. This study aimed to develop a minimal approach to measure the two parameters and to examine their intra- and interday reliability during walking., Methods: The minimal markerset uses markers at the lateral and medial caput of the 1 st and 5 th metatarsals, respectively, at the dorsal calcaneus and at the tuberosity of the navicular bone. Dynamic navicular drop and drift were assessed with three-dimensional motion capture in 21 healthy individuals using a single-examiner test-retest study design., Results: Intra- and interday repeatability were 1.1 mm ( ICC 21 0.97) and 2.3 mm ( ICC 21 0.87) for dynamic navicular drop and 1.5 mm ( ICC 21 0.96) and 5.3 mm ( ICC 21 0.46) for dynamic navicular drift. The contribution of instrumental errors was estimated to 0.25 mm for dynamic navicular drop and 0.86 mm for dynamic navicular drift., Conclusions: Interday reliability was generally worse than intraday reliability primary due to day-to-day variations in movement patterns and the contribution of instrumental errors was below 23% for dynamic navicular drop but reached 57% for dynamic navicular drift. The minimal markerset allows to simply transfer the known concepts of navicular drop and drift from quasi-static clinical test conditions to functional tasks, which is recommended to more closely relate assessments to the functional behavior of the foot., Competing Interests: The study was approved by the ethics committee of the canton of Bern (KEK number Z007/12) and all participants signed informed consent.All participants were informed that the findings of the work may be published based on their data in fully anonymized form.The funding source had no involvement in study design, data collection, analysis and interpretation of data, in writing the manuscript and in the decision to submit the manuscript for publication. All authors state no conflict of interest.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Background: It has been reported that hallux valgus (HV) is associated with axial rotation of the first metatarsal (1MT). However, the association between HV and torsion of the 1MT head with respect to the base has not been previously investigated. The present study examined whether there was a significant difference in 1MT torsion between HV and control groups., Methods: Three-dimensional (3D) computed tomography (CT) scans of 39 ft were obtained, and 3D surface models of the 1MT were generated to quantify the torsion of the head with respect to the base. The HV group consisted of 27 ft from 27 women (69.5 ± 7.5 years old). Only the feet of HV patients with an HV angle >20° on weight-bearing radiography were selected for analysis. The control group consisted of 12 ft from 12 women (67.7 ± 7.2 years old). In a virtual 3D space, two unit vectors, which describe the orientation of the 1MT head and base, were calculated. The angle formed by these two unit vectors representing 1MT torsion was compared between the control and hallux valgus groups., Results: The mean (± standard deviation) of the torsional angle of the 1MT was 17.6 (± 7.7)° and 4.7 (± 4.0)° in the HV and control groups, respectively, and the difference was significant ( p  < 0.01)., Conclusions: This is the first study, to the best of our knowledge, to investigate 1MT torsion in HV patients using CT-based 3D analysis. The 1MT showed significant eversion in hallux valgus patients compared to control group patients.

Background: Foot orthoses are frequently used in sports for the treatment of overuse complaints with sufficient evidence available for certain foot-related overuse pathologies like plantar fasciitis, rheumatoid arthritis and foot pain (e.g., metatarsalgia). One important aim is to reduce plantar pressure under prominent areas like metatarsal heads. For the forefoot region, mainly two common strategies exist: metatarsal pad (MP) and forefoot cushioning (FC). The aim of this study was to evaluate which of these orthosis concepts is superior in reducing plantar pressure in the forefoot during running., Methods: Twenty-three (13 female, 10 male) asymptomatic runners participated in this cross-sectional experimental trial. Participants ran in a randomised order under the two experimental (MP, FC) conditions and a control (C) condition on a treadmill (2.78 ms -1 ) for 2 min, respectively. Plantar pressure was measured with the in-shoe plantar pressure measurement device pedar-x®-System and mean peak pressure averaged from ten steps in the forefoot (primary outcome) and total foot was analysed. Insole comfort was measured with the Insole Comfort Index (ICI, sum score 0-100) after each running trial. The primary outcome was tested using the Friedman test (α = 0.05). Secondary outcomes were analysed descriptively (mean ± SD, lower & upper 95%-CI, median and interquartile-range (IQR))., Results: Peak pressure [kPa] in the forefoot was significantly lower wearing FC (281 ± 80, 95%-CI: 246-315) compared to both C (313 ± 69, 95%-CI: 283-343; p  = .003) and MP (315 ± 80, 95%-CI: 280-350; p  = .001). No significant difference was found between C and MP ( p  = .858). Peak pressures under the total foot were: C: 364 ± 82, 95%-CI: 328-399; MP: 357 ± 80, 95%-CI: 326-387; FC: 333 ± 81 95%-CI: 298-368. Median ICI sum scores were: C 50, MP 49, FC 64., Conclusions: In contrast to the metatarsal pad orthosis, the forefoot cushioning orthosis achieved a significant reduction of peak pressure in the forefoot of recreational runners. Consequently, the use of a prefabricated forefoot cushioning orthosis should be favoured over a prefabricated orthosis with an incorporated metatarsal pad in recreational runners with normal height arches.

Mice raised in experimental habitats containing an artificial network of narrow "arboreal" supports frequently use hallucal grasps during locomotion. Therefore, mice in these experiments can be used to model a rudimentary form of arboreal locomotion in an animal without other morphological specializations for using a fine branch niche. This model would prove useful to better understand the origins of arboreal behaviors in mammals like primates. In this study, we examined if locomotion on these substrates influences the mid-diaphyseal cross-sectional geometry of mouse metatarsals. Thirty CD-1/ICR mice were raised in either arboreal (composed of elevated narrow branches of varying orientation) or terrestrial (flat ramps and walkways that are stratified) habitats from weaning (21 days) to adulthood (≥4 months). After experiments, the hallucal metatarsal (Mt1) and third metatarsal (Mt3) for each individual were isolated and micro-computed tomography (micro-CT) scans were obtained to calculate mid-shaft cross-sectional area and polar section modulus. Arboreal mice had Mt1s that were significantly more robust. Mt3 cross sections were not significantly different between groups. The arboreal group also exhibited a significantly greater Mt1/Mt3 ratio for both robusticity measures. We conclude that the hallucal metatarsal exhibits significant phenotypic plasticity in response to arboreal treatment due to habitual locomotion that uses a rudimentary hallucal grasp. Our results support the hypothesis that early adaptive stages of fine branch arboreality should be accompanied by a slightly more robust hallux associated with the biomechanical demands of this niche., (© 2015 Wiley Periodicals, Inc.)

Forefoot pain is a common problem in older people. We determined whether plantar pressures during gait and the relative lengths of the lesser metatarsals differ between older people with and without plantar forefoot pain. Dynamic plantar pressure assessment during walking was undertaken using the Tekscan MatScan® system in 118 community-dwelling older people (44 males and 74 females), mean age 74 (standard deviation=5.9) years, 43 (36%) of whom reported current or previous plantar forefoot pain. The relative lengths of metatarsals 1-5 were determined from weightbearing X-rays. Participants with current or previous plantar forefoot pain exhibited significantly (p=0.032) greater peak plantar pressure under metatarsal heads 3-5 (1.93 ± 0.41 kg/cm(2) vs. 1.74 ± 0.48 kg/cm(2) ). However, no differences were found in relative metatarsal lengths between the groups. These findings indicate that older people with forefoot pain generate higher peak plantar pressures under the lateral metatarsal heads when walking, but do not exhibit relatively longer lesser metatarsals. Other factors may be responsible for the observed pressure increase, such as reduced range of motion of the metatarsophalangeal joints and increased stiffness of plantar soft tissues., (Copyright © 2012 Orthopaedic Research Society.)

This study evaluated healing of equine metatarsal osteotomies and ostectomies in response to percutaneous injection of adenoviral (Ad) bone morphogenetic protein (BMP)-2, Ad-BMP-6, or beta-galactosidase protein vector control (Ad-LacZ) administered 14 days after surgery. Radiographic and quantitative computed tomographic assessment of bone formation indicated greater and earlier mineralized callus in both the osteotomies and ostectomies of the metatarsi injected with Ad-BMP-2 or Ad-BMP-6. Peak torque to failure and torsional stiffness were greater in osteotomies treated with Ad-BMP-2 than Ad-BMP-6, and both Ad-BMP-2- and Ad-BMP-6-treated osteotomies were greater than Ad-LacZ or untreated osteotomies. Gene expression of ostectomy mineralized callus 8 weeks after surgery indicated upregulation of genes related to osteogenesis compared to intact metatarsal bone. Expression of transforming growth factor beta-1, cathepsin H, and gelsolin-like capping protein were greater in Ad-BMP-2- and Ad-BMP-6-treated callus compared to Ad-LacZ-treated or untreated callus. Evidence of tissue biodistribution of adenovirus in distant organs was not identified by quantitative PCR, despite increased serum antiadenoviral vector antibody. This study demonstrated a greater relative potency of Ad-BMP-2 over Ad-BMP-6 in accelerating osteotomy healing when administered in this regimen, although both genes were effective at increasing bone at both osteotomy and ostectomy sites.

Standardized particulate bone constructs, obtained by expanding autologous mesenchymal stem cells (MSCs) onto coral granules in vitro, were transplanted into long-bone, critical-size defects in sheep. Control experiments were also performed in which autologous bone grafts were implanted. Defect cavities were lined with a preformed vascularized membrane (induced by temporarily inserting a cement spacer for 6 weeks prior to bone construct implantation), which served as a mold keeping the engineered bone granules in place. Radiographic, histological, and computed tomographic tests performed 6 months later showed that the osteogenic abilities of the engineered construct and autograft were significantly greater than those of coral scaffold alone. No significant differences were found between the amount of newly formed bone in defects filled with coral/MSCs and those filled with autograft, yet radiological scores differed significantly between the two groups (21% and 100% healed cortices, respectively). The present study on a clinically relevant animal model provides the first evidence that standardized particulate bone constructs can be used to repair large bone defects and that their osteogenic ability approaches that of bone autograft, the bone repair benchmark. By proving feasibility, the present study makes possible the treatment of segmental bone losses with bone constructs engineered from granules, a process which is much simpler than preparing customized massive constructs using computer-assisted techniques. Important parameters, such as the rate of scaffold resorption and the number of MSCs to be seeded on the scaffolds, need to be optimized before reaching pertinent definitive conclusions., ((c) 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

This paper is concerned with the theoretical prediction of stress fractures in the bones of athletes, soldiers and others during periods of intensive exercise. Previously [J. Orthop. Res. 19 (2001) 919] we showed that test data on the fatigue strength of bone in vitro could be described using Weibull's probabilistic model, allowing predictions to be made of the probability of failure as a function of time under cyclic loading. This paper extends the earlier argument by including two living processes which act to reduce the incidence of failure: (i) repair of damage, and; (ii) adaptation by bone deposition. Having incorporated these aspects into the mathematical model, we applied the theory to a specific case: the human second metatarsal. We predicted a 17% incidence of stress fractures, all occurring within 6 weeks of commencement of the training programme. These predictions agreed well with clinical findings. Interestingly, we concluded that the major effect in preventing stress fractures comes from repair rather than from adaptation, which has a relatively minor role because it acts more slowly.

We present a hypothesis of tyrannosaurid foot function termed the "tensile keystone model," in which the triangular central metatarsal and elastic ligaments dynamically strengthened the foot. The tyrannosaurid arctometatarsus, in which the central metatarsal is proximally constricted, displays osteological correlates of distal intermetatarsal ligaments. The distal wedge-like imbrication of tyrannosaurid metatarsals indicates that rebounding ligaments drew the outer elements towards the middle digit early in the stance phase, unifying the arctometatarsus under high loadings. This suggests increased stability and resistance to dissociation and implies, but does not demonstrate, greater agility than in large theropods without an arctometatarsus., (Copyright 2002 Wiley-Liss, Inc.)

The objective of this study was to determine if the material properties of bone at the lamellar level are related to the predominant mode and magnitude of mechanical strain experienced in situ. The tibia and first metatarsal bones of five unpaired cadaveric lower extremities were instrumented with strain gauge rosettes and subjected to repeated loading trials in an apparatus that replicates the muscle forces and external loads experienced by the foot and shank while walking. The spatial distributions of axial strain within diaphyseal cross-sections taken from each bone were subsequently determined. Nanoindentation measurements were then performed on the same cross-sections to determine the compressive elastic moduli of individual lamellae located within osteonal, interstitial, and outer circumferential microstructures. Twenty percent of the variance in interstitial elastic modulus within cross-sections of diaphyseal bone was explained by local strain magnitude. Lamellae residing in regions of compressive strain displayed significantly higher compressive elastic modulus values than those located in predominantly tensile regions (19.9 +/- 1.6 GPa compared to 17.9 +/- 1.7 GPa, p < 0.05). Elastic moduli of interstitial lamellae were 11% greater than those of osteonal or outer circumferential lamellae, irrespective of strain or anatomical location (p < 0.001). Differences exist in the material properties of individual bone lamellae located within different anatomical regions and different microstructures, and these differences are related to the distribution of axial strain. These findings suggest that mechanical strain, or another closely related variable, may influence the design and ultimate mechanical behavior of the extra-cellular matrix found in lamellar bone. This tissue heterogeneity is of potential importance in bone fragility and adaptation.

The perching foot of living birds is commonly characterized by a reversed or opposable digit I (hallux). Primitively, the hallux of nonavian theropod dinosaurs was unreversed and lay parallel to digits II-IV. Among basal birds, a unique digital innovation evolved in which the hallux opposes digits II-IV. This digital configuration is critical for grasping and perching. I studied skeletons of modern birds with a range of hallucal designs, from unreversed (anteromedially directed) to fully reversed (posteriorly directed). Two primary correlates of hallucal orientation were revealed. First, the fossa into which metatarsal I articulates is oriented slightly more posteriorly on the tarsometatarsus, rotating the digit as a unit. Second, metatarsal I exhibits a distinctive torsion of its distal shaft relative to its proximal articulation with the tarsometatarsus, reorienting the distal condyles and phalanges of digit I. Herein, I present a method that facilitates the re-evaluation of hallucal orientation in fossil avians based on morphology alone. This method also avoids potential misinterpretations of hallucal orientation in fossil birds that could result from preserved appearance alone., (Copyright 2001 Wiley-Liss, Inc.)

This study addressed the theory that local mechanical loading may influence the development of embryonic long bones. Embryonic mouse metatarsal rudiments were cultured as whole organs, and the geometry of the primary ossification center was compared with that of rudiments that had developed in utero. The mineralization front in vivo was found to be nearly straight, whereas in vitro it acquired a more convex shape due to a slower mineralization rate at the periphery of the mineralized cylinder. A poroelastic finite element analysis was performed to calculate the local distributions of distortional strain and fluid pressure at the mineralization front in the metatarsal during loading in vivo as a result of muscle contractions in the embryonic hindlimbs. The distribution of fluid pressure from the finite element analysis could not explain the difference in mineralization shape. The most likely candidate for the difference was the distortional strain, resulting from muscle contraction, which is absent in vitro, because its value at the periphery was significantly higher than in the center of the tissue. Without external loads, the mineralization process may be considered as pre-programmed, starting at the center of the tissue and resulting in a spherical mineralization front. Strain modulates the rate of the mineralization process in vivo, resulting in the straight mineralization front. These results confirm that disturbances in muscle development are likely to produce disturbed mineralization patterns, resulting in a disordered osteogenic process.

The sole under the metatarsal heads functions as a shock absorber during walking and running. The mechanical properties of the sole provide the primary defense against the development of metatarsalgia and foot ulceration. However, limited information about these properties has been documented. In this study, we used ultrasonography to evaluate the mechanical properties, including unloaded thickness, compressibility index, elastic modulus, and energy dissipation ratio, of the sole in 20 healthy subjects. The unloaded thickness decreased progressively from the first to the fifth metatarsal heads, with values of 1.50, 1.36, 1.25, 1.14, and 1.04 cm. The sole under the first metatarsal head had the greatest values for the compressibility index and elastic modulus (55.9% and 1.39 kg/cm2), and the sole under the third metatarsal head had the smallest values (50.8% and 1.23 kg/cm2). The sole under the fifth metatarsal head had the greatest energy dissipation ratio (33.7%), followed by that under the third, second, first, and fourth metatarsal heads. Multivariate adjusted linear regression showed that the unloaded thickness, compressibility index, and elastic modulus values increased significantly with age and body weight (p < 0.05) and that the energy dissipation ratio increased significantly with body weight (p < 0.05)

Second-intention healing of deep wounds was studied in 5 horses and 5 ponies. Standardised wounds were created on the distal limbs and hind quarters. Wounds on the metatarsi extended onto the metatarsal bone; the depth of the wounds in the femoral biceps muscle was 18 mm. The wound margins were marked by tattoos. Photographs were taken at weekly intervals to determine the wound area. The relative contribution of contraction and epithelialisation to wound closure was quantified by means of the tattoos. Swelling of the limbs was measured; and regularity and aspect of the granulation tissue were semi-quantitatively scored. Second-intention wound healing occurred significantly faster in ponies than in horses, and muscle wounds healed significantly faster than metatarsal wounds. These marked differences reflected the greater contribution of contraction to wound healing. Moreover, demarcation was seen earlier and a healthy granulation bed developed more rapidly in ponies, whereas in horses the granulation tissue remained irregular and purulent for longer. Healing of the metatarsal wounds of horses differed markedly from that of all other wounds: these wounds increased to almost twice their original size in the first 2 weeks, exuberant granulation tissue was persistent, epithelialisation started later, and contraction played a minor role in wound closure. Limb swelling was greater in horses than in ponies. Periosteal new bone formation was more extensive, and was active over a longer period in the metatarsal bones of horses than of ponies. From this study it is concluded that second-intention healing of deep wounds occurs faster in ponies than in horses. This difference can be largely attributed to a more pronounced and faster wound contraction in ponies than in horses. Therefore, attempts to improve second-intention wound healing in clinical practice should be directed at stimulation of wound contraction.

The effect of electrical stimulation by means of selected electromagnetic field devices on healing of cannon bone osteotomies in horses was examined. The defects were created as 3 cm x 1 mm longitudinal osteotomies through the dorsal cortices of the mid-metacarpi/metatarsi of adult horses. This type of defect would asses bone healing in a situation similar to an acute, stable fracture of the cortex. Three electromagnetic devices of different design were tested in three different groups of horses. Healing was evaluated radiographically and histologically. Results showed that osteotomies treated with the electromagnetic devices healed similarly to untreated controls. Our conclusion is that the electromagnetic devices studied did not have a local effect on the repair process of an acute, stable, osseous defect.