INTRODUÇÃO: As alterações do comprimento relativo dos metatarsais no plano axial são consideradas por muitos autores uma causa de distribuição inadequada da carga durante a marcha, sobrecarregando as estruturas plantares do antepé, culminando com a metatarsalgia. A meta do tratamento cirúrgico dessa síndrome é estabelecer o alinhamento da fórmula metatarsal. Porém, muitos estudos evidenciam uma taxa de 15% de recidiva da metatarsalgia após a reconstrução do formato preconizado no plano axial, conduzindo a um questionamento sobre a importância do alinhamento das cabeças dos metatarsais no plano coronal. OBJETIVO: Esse estudo tem como objetivo avaliar o padrão de alinhamento das cabeças dos metatarsais no plano coronal com carga, em indivíduos sem e com metatarsalgia. MÉTODO: Estudo transversal, avaliou 106 indivíduos entre 30 a 65 anos, dividindo-os em dois grupos de 106 pés cada, um sem dor, deformidades e calosidades nos pés e outro grupo com metatarsalgia entre os 2º, 3º e 4º metatarsais. O recrutamento dos indivíduaos foi realizado no Pronto Socorro do IOT e no ambulatório do IOT HC FMUSP, respeitando os critérios de inclusão, exclusão e aplicando o Termo de Consentimento Livre e Esclarecido. Indivíduos com deformidades no mediopé, retropé e tornozelo, pacientes com cirurgias ou fraturas prévias no pé, doenças reumatológicas e síndromes osteoneuromusculares, não foram incluídos. Após a seleção, os indivíduos foram submetidos a duas radiografias, uma axial do antepé com carga, avaliando o plano coronal de modo a aferir as alturas das cabeças dos metatarsais, e uma anteroposterior dos pés com carga, determinando o comprimento de cada raio. A análise estatística foi realizada, comparando as medidas entre os grupos. RESULTADOS: Foram avaliados 106 indivíduos, divididos em dois grupos com 106 pés cada. No grupo com metatarsalgia, 34 pés (32%) eram de pacientes do sexo masculino, apresentando uma média de idade de 49,5 anos. Foram identificados 33 pés com hálux valgo no grupo com metatarsalgia. No grupo sem patologia 54 pés (51%) eram de pacientes do sexo masculino, apresentando uma média de idade de 44,6 anos. As variáveis antropométricas como tamanho do pé, peso, altura e IMC, entre os grupos, não apresentaram diferença estatística. As cabeças dos metatarsais em ambos grupos se distribuíram em formato não retilíneo no plano coronal, seguindo a fórmula M1 M3 > M4=M5. O apoio distal do 1º raio apresentou uma posição mais plantar no grupo com metatarsalgia (p=0,000). CONCLUSÃO: As cabeças dos metatarsais em indivíduos com metatarsalgia e sem deformidade em valgo do 1º dedo, se alinharam no plano coronal de modo que M1 M3 > M4=M5, sendo M1 < M3, M1 < M4 e o M1 < M5. As cabeças dos metatarsais em indivíduos sem dor, calosidades e deformidades no antepé, se alinharam no plano coronal de modo que M1 M3 > M4=M5, sendo M1 < M3 e M1=M4=M5. No plano coronal o ponto de apoio do M1 se posicionou mais plantar nos pés de indivíduos com metatarsalgia / INTRODUCTION: Many authors consider the differences in the relative length of metatarsals in the axial plane, the cause of inadequate load distribution during the gait, overloading the forefoot plantar structures, culminating with metatarsalgia. The realignment of the metatarsal formula is the goal of surgical treatment of this syndrome. However, many studies have shown a 15% rate of metatarsalgia recurrence after the reconstruction in the axial plane, questioning the importance of the metatarsal heads alignment in the coronal plane. OBJECTIVE: This study aims to evaluate the alignment pattern of metatarsal heads in the coronal plane in individuals with and without metatarsalgia. METHODS: A cross-sectional study evaluated 106 individuals between 30 and 65 years old. They were divided in two groups of 106 feet each, one without foot pathologies and another group with metatarsalgia between the 2nd, 3rd and 4th metatarsals. The recruitment was performed at the IOT HC FMUSP for both groups, respecting the criteria of inclusion, exclusion and applying the Informed Consent Term. Individuals with midfoot, hindfoot and ankle deformities, patients with previous surgeries or fractures in the foot, rheumatologic diseases and osteoneuromuscular syndromes were not included. After the selection, the subjects were submitted to one weightbearing forefoot axial radiograph, evaluating the coronal plane in order to verify the heights of the metatarsals heads, and other weightbearing anteroposterior foot radiograph, determining the length of each ray. Statistical analysis was performed comparing the measurements between groups. RESULTS: A hundred six individuals were evaluated, forming two groups with 106 feet each. The group with metatarsalgia presented 34 male patients feet (32%), with a mean age of 49.5 years. Thirty-three feet with hallux valgus were identified in the metatarsalgia group. In the non-pathological group were found 54 male patients feet (51%), with a mean age of 44.6 years. Anthropometric variables such as foot size, body weight, height and BMI between the groups did not present statistical difference. The metatarsal heads in both groups were distributed in curved line in the coronal plane, following the formula M1 M3 > M4 = M5. The distal support of the 1st ray was positioned more plantar in the metatarsalgia group (p = 0.000). CONCLUSION: The metatarsal heads in individuals with metatarsalgia and no hallux valgus, were aligned in the coronal plane following this formula M1 M3 > M4 = M5, with M1 < M3, M1 < M4 and M1 < M5. The metatarsal heads in individuals without pain, callosities and forefoot deformities, were aligned in the coronal plane following the position M1 M3 > M4 = M5, with M1 < M3 and M1 = M4 = M5. In the coronal plane, the M1 weightbearing point was more plantar in the feet of individuals with metatarsalgia

INTRODUÇÃO: As alterações do comprimento relativo dos metatarsais no plano axial são consideradas por muitos autores uma causa de distribuição inadequada da carga durante a marcha, sobrecarregando as estruturas plantares do antepé, culminando com a metatarsalgia. A meta do tratamento cirúrgico dessa síndrome é estabelecer o alinhamento da fórmula metatarsal. Porém, muitos estudos evidenciam uma taxa de 15% de recidiva da metatarsalgia após a reconstrução do formato preconizado no plano axial, conduzindo a um questionamento sobre a importância do alinhamento das cabeças dos metatarsais no plano coronal. OBJETIVO: Esse estudo tem como objetivo avaliar o padrão de alinhamento das cabeças dos metatarsais no plano coronal com carga, em indivíduos sem e com metatarsalgia. MÉTODO: Estudo transversal, avaliou 106 indivíduos entre 30 a 65 anos, dividindo-os em dois grupos de 106 pés cada, um sem dor, deformidades e calosidades nos pés e outro grupo com metatarsalgia entre os 2º, 3º e 4º metatarsais. O recrutamento dos indivíduaos foi realizado no Pronto Socorro do IOT e no ambulatório do IOT HC FMUSP, respeitando os critérios de inclusão, exclusão e aplicando o Termo de Consentimento Livre e Esclarecido. Indivíduos com deformidades no mediopé, retropé e tornozelo, pacientes com cirurgias ou fraturas prévias no pé, doenças reumatológicas e síndromes osteoneuromusculares, não foram incluídos. Após a seleção, os indivíduos foram submetidos a duas radiografias, uma axial do antepé com carga, avaliando o plano coronal de modo a aferir as alturas das cabeças dos metatarsais, e uma anteroposterior dos pés com carga, determinando o comprimento de cada raio. A análise estatística foi realizada, comparando as medidas entre os grupos. RESULTADOS: Foram avaliados 106 indivíduos, divididos em dois grupos com 106 pés cada. No grupo com metatarsalgia, 34 pés (32%) eram de pacientes do sexo masculino, apresentando uma média de idade de 49,5 anos. Foram identificados 33 pés com hálux valgo no grupo com metatarsalgia. No grupo sem patologia 54 pés (51%) eram de pacientes do sexo masculino, apresentando uma média de idade de 44,6 anos. As variáveis antropométricas como tamanho do pé, peso, altura e IMC, entre os grupos, não apresentaram diferença estatística. As cabeças dos metatarsais em ambos grupos se distribuíram em formato não retilíneo no plano coronal, seguindo a fórmula M1 M3 > M4=M5. O apoio distal do 1º raio apresentou uma posição mais plantar no grupo com metatarsalgia (p=0,000). CONCLUSÃO: As cabeças dos metatarsais em indivíduos com metatarsalgia e sem deformidade em valgo do 1º dedo, se alinharam no plano coronal de modo que M1 M3 > M4=M5, sendo M1 < M3, M1 < M4 e o M1 < M5. As cabeças dos metatarsais em indivíduos sem dor, calosidades e deformidades no antepé, se alinharam no plano coronal de modo que M1 M3 > M4=M5, sendo M1 < M3 e M1=M4=M5. No plano coronal o ponto de apoio do M1 se posicionou mais plantar nos pés de indivíduos com metatarsalgia / INTRODUCTION: Many authors consider the differences in the relative length of metatarsals in the axial plane, the cause of inadequate load distribution during the gait, overloading the forefoot plantar structures, culminating with metatarsalgia. The realignment of the metatarsal formula is the goal of surgical treatment of this syndrome. However, many studies have shown a 15% rate of metatarsalgia recurrence after the reconstruction in the axial plane, questioning the importance of the metatarsal heads alignment in the coronal plane. OBJECTIVE: This study aims to evaluate the alignment pattern of metatarsal heads in the coronal plane in individuals with and without metatarsalgia. METHODS: A cross-sectional study evaluated 106 individuals between 30 and 65 years old. They were divided in two groups of 106 feet each, one without foot pathologies and another group with metatarsalgia between the 2nd, 3rd and 4th metatarsals. The recruitment was performed at the IOT HC FMUSP for both groups, respecting the criteria of inclusion, exclusion and applying the Informed Consent Term. Individuals with midfoot, hindfoot and ankle deformities, patients with previous surgeries or fractures in the foot, rheumatologic diseases and osteoneuromuscular syndromes were not included. After the selection, the subjects were submitted to one weightbearing forefoot axial radiograph, evaluating the coronal plane in order to verify the heights of the metatarsals heads, and other weightbearing anteroposterior foot radiograph, determining the length of each ray. Statistical analysis was performed comparing the measurements between groups. RESULTS: A hundred six individuals were evaluated, forming two groups with 106 feet each. The group with metatarsalgia presented 34 male patients feet (32%), with a mean age of 49.5 years. Thirty-three feet with hallux valgus were identified in the metatarsalgia group. In the non-pathological group were found 54 male patients feet (51%), with a mean age of 44.6 years. Anthropometric variables such as foot size, body weight, height and BMI between the groups did not present statistical difference. The metatarsal heads in both groups were distributed in curved line in the coronal plane, following the formula M1 M3 > M4 = M5. The distal support of the 1st ray was positioned more plantar in the metatarsalgia group (p = 0.000). CONCLUSION: The metatarsal heads in individuals with metatarsalgia and no hallux valgus, were aligned in the coronal plane following this formula M1 M3 > M4 = M5, with M1 < M3, M1 < M4 and M1 < M5. The metatarsal heads in individuals without pain, callosities and forefoot deformities, were aligned in the coronal plane following the position M1 M3 > M4 = M5, with M1 < M3 and M1 = M4 = M5. In the coronal plane, the M1 weightbearing point was more plantar in the feet of individuals with metatarsalgia

Il a été démontré que la torsion des têtes métatarsiennes est influencée par le mode de locomotion chez les primates et peut être utilisée pour déterminer la présence ou non d’une arche longitudinale chez les ancêtres hominines. Chez l’humain moderne, l’arche longitudinale rend le pied plus inversé que chez les grands singes, provoquant un léger basculement de l’axe dorsoplantaire de l’articulation proximale des métatarses. Ainsi, les têtes métatarsiennes subissent une torsion par rapport à l’axe de la diaphyse pour que leur surface plantaire reste parallèle au sol. Comme les femmes ont une arche longitudinale plus haute que les hommes et comme le port du soulier à semelles rigides provoque des changements morphologiques au niveau du pied, rendant l’arche longitudinale plus haute et l’hallux moins divergeant, il est attendu que la torsion métatarsienne soit différente selon le sexe et le type de soulier porté. Ce mémoire examine donc l’effet du contexte environnemental du pied et de la plasticité de la torsion des têtes métatarsiennes en comparant différentes populations humaines. L’échantillon disponible pour cette étude est constitué de 166 individus provenant de 18 sites archéologiques différents comprenant 57 hommes, 35 femmes et 74 individus de sexe indéterminé qui ont été divisés en quatre grands groupes : Amérindiens, Inuits, Militaires et Euro-canadiens. Il n’y a aucune différence de torsion entre les hommes et les femmes, ce qui suggère que la différence de hauteur de l’arche longitudinale entre les hommes et les femmes n’est pas assez importante pour être perçues au niveau de la torsion des têtes métatarsiennes. La topographie ne semble pas provoquer assez de modifications au niveau du pied pour provoquer une torsion différentielle des têtes métatarsiennes. Cependant, la surface du sol, plat ou accidenté, pourrait être un facteur modifiant ce trait. Finalement, le port de souliers constrictif à semelles dures comparativement aux souliers souples, tels les mocassins, provoque une torsion différentielle des têtes métatarsiennes. Les individus chaussant des souliers à semelles souples ont un premier métatarsien présentant une plus grande éversion et un troisième, quatrième et cinquième métatarsien présentant une plus petite éversion comparativement aux individus chaussant des souliers constrictifs. Ces résultats viennent appuyer l’hypothèse de la capacité plastique de la torsion des têtes métatarsiennes. / It has been shown that the metatarsals head torsion can be influenced by the mode of locomotion in primates and can be used to determine the presence or absence of a longitudinal arch in hominin ancestors. In modern humans, the longitudinal arch results in a foot more inverted than in apes, causing a slight tilting of the dorsoplantary axis of the metatarsals proximal joints. Thus, the metatarsal heads undergo torsion relative to the axis of the shaft so their plantar surface lie parallel to the ground. Since women have a higher longitudinal arch than men and since wearing hard sole shoes causes morphological changes in the foot, making the longitudinal arch higher and the hallux less abducted, it is expected that torsion will be different according to sex and type of shoes worn. By comparing different human populations, this paper examines whether metatarsal torsion is a plastic trait that can be influenced by the loading environment. The sample available for this study, consists of 166 individuals from 18 different archaeological sites including 57 men, 35 women and 74 of indetermined sex that were divided into four groups: Amerinds, Inuits, Military and Euro-canadian. There is no significant difference in torsion between men and women, suggesting that the slight difference in longitudinal arch height between men and women is not sufficient to be perceived in metatarsal variation torsion. The topography of the land does not seem to cause significant changes in the foot such as torsion. However, the surface of the ground, flat or irregular, could be a factor modifying torsion. Finally, wearing constrictive shoes with hard soles compared to flexible shoes, such as moccasins, increased variation in torsion angles. Individuals known to wear moccasins present more eversion of the first metatarsal and less eversion of the third, fourth and fifth metatarsals compared to individuals who used to wear constrictive footwear. These results support the hypothesis that metatarsal torsion is a relatively plastic feature.

Il a été démontré que la torsion des têtes métatarsiennes est influencée par le mode de locomotion chez les primates et peut être utilisée pour déterminer la présence ou non d’une arche longitudinale chez les ancêtres hominines. Chez l’humain moderne, l’arche longitudinale rend le pied plus inversé que chez les grands singes, provoquant un léger basculement de l’axe dorsoplantaire de l’articulation proximale des métatarses. Ainsi, les têtes métatarsiennes subissent une torsion par rapport à l’axe de la diaphyse pour que leur surface plantaire reste parallèle au sol. Comme les femmes ont une arche longitudinale plus haute que les hommes et comme le port du soulier à semelles rigides provoque des changements morphologiques au niveau du pied, rendant l’arche longitudinale plus haute et l’hallux moins divergeant, il est attendu que la torsion métatarsienne soit différente selon le sexe et le type de soulier porté. Ce mémoire examine donc l’effet du contexte environnemental du pied et de la plasticité de la torsion des têtes métatarsiennes en comparant différentes populations humaines. L’échantillon disponible pour cette étude est constitué de 166 individus provenant de 18 sites archéologiques différents comprenant 57 hommes, 35 femmes et 74 individus de sexe indéterminé qui ont été divisés en quatre grands groupes : Amérindiens, Inuits, Militaires et Euro-canadiens. Il n’y a aucune différence de torsion entre les hommes et les femmes, ce qui suggère que la différence de hauteur de l’arche longitudinale entre les hommes et les femmes n’est pas assez importante pour être perçues au niveau de la torsion des têtes métatarsiennes. La topographie ne semble pas provoquer assez de modifications au niveau du pied pour provoquer une torsion différentielle des têtes métatarsiennes. Cependant, la surface du sol, plat ou accidenté, pourrait être un facteur modifiant ce trait. Finalement, le port de souliers constrictif à semelles dures comparativement aux souliers souples, tels les mocassins, provoque une torsion différentielle des têtes métatarsiennes. Les individus chaussant des souliers à semelles souples ont un premier métatarsien présentant une plus grande éversion et un troisième, quatrième et cinquième métatarsien présentant une plus petite éversion comparativement aux individus chaussant des souliers constrictifs. Ces résultats viennent appuyer l’hypothèse de la capacité plastique de la torsion des têtes métatarsiennes. / It has been shown that the metatarsals head torsion can be influenced by the mode of locomotion in primates and can be used to determine the presence or absence of a longitudinal arch in hominin ancestors. In modern humans, the longitudinal arch results in a foot more inverted than in apes, causing a slight tilting of the dorsoplantary axis of the metatarsals proximal joints. Thus, the metatarsal heads undergo torsion relative to the axis of the shaft so their plantar surface lie parallel to the ground. Since women have a higher longitudinal arch than men and since wearing hard sole shoes causes morphological changes in the foot, making the longitudinal arch higher and the hallux less abducted, it is expected that torsion will be different according to sex and type of shoes worn. By comparing different human populations, this paper examines whether metatarsal torsion is a plastic trait that can be influenced by the loading environment. The sample available for this study, consists of 166 individuals from 18 different archaeological sites including 57 men, 35 women and 74 of indetermined sex that were divided into four groups: Amerinds, Inuits, Military and Euro-canadian. There is no significant difference in torsion between men and women, suggesting that the slight difference in longitudinal arch height between men and women is not sufficient to be perceived in metatarsal variation torsion. The topography of the land does not seem to cause significant changes in the foot such as torsion. However, the surface of the ground, flat or irregular, could be a factor modifying torsion. Finally, wearing constrictive shoes with hard soles compared to flexible shoes, such as moccasins, increased variation in torsion angles. Individuals known to wear moccasins present more eversion of the first metatarsal and less eversion of the third, fourth and fifth metatarsals compared to individuals who used to wear constrictive footwear. These results support the hypothesis that metatarsal torsion is a relatively plastic feature.

La course d'ultra-trail en montagne provoque de nombreuses altérations d'ordre biomécaniques, physiologiques, neuro-musculaires, posturales et psychologiques qui peuvent engendrer certaines blessures. Cependant, assez peu d'études se sont intéressées aux modifications que peuvent subir les pieds. C'est dans ce cadre que nous avons réalisé 3 études. La première effectuée auprès de 10 coureurs a montré que les avants-pieds s'élargissent et la pression plantaire sous l'avant-pied augmente à partir de la mi-distance d'une épreuve d'ultra-trail de 170 km (UTMB®). La surpression sous l'avant-pied qui est due au déplacement vers l'avant du centre de pression, est susceptible d'accroitre le risque de fracture de fatigue des métatarses. Ces modifications qui ont été observées jusqu'à la fin de la compétition sont probablement liées à la fatigue des sujets. Pour contrecarrer ces modifications, nous avons proposé d'utiliser des semelles orthopédiques moulées comportant chacune une barre rétro capitale (BRC) placée en arrière des têtes métatarsiennes. La 2ème étude réalisée chez 48 coureurs a montré que cet élément orthopédique permet lors du maintien de la posture debout de diminuer les pressions plantaires sous les avants-pieds, de reculer le centre de pression, mais aussi les centres articulaires de la hanche, des épaules et de la tête. La 3ème étude avait pour objectif d'évaluer chez 10 coureurs à pieds l'effet immédiat, à court terme (après 4 semaines) et moyen terme (après 12 semaines) du port des semelles BRC sur la répartition des pressions plantaires et la cinématique articulaire. Un groupe contrôle de taille égale a utilisé pendant la même période des semelles moulées qui ne comportaient aucun élément orthopédique. Cette étude longitudinale a montré que les pressions plantaires sous les têtes métatarsiennes étaient réduites immédiatement avec le port des semelles BRC. Après 4 semaines, cette réduction s'accentuait et l'angle de flexion de la cheville était augmenté lors de l'appui. Après 12 semaines, l'extension maximale du genou était augmentée et la plupart de ces modifications étaient aussi observées même si les sujets utilisent des semelles plates. Aucune variable n'a été modifiée chez les sujets du groupe contrôle. En ce qui concerne les applications pratiques de ces travaux de thèse, au regard de nos résultats, nous pouvons conseiller aux coureurs de longue distance soufrant de douleur au niveau de l'avant-pied de choisir des chaussures un peu plus larges et, d'utiliser des semelles orthopédiques BRC pour réduire la pression sous l'avant-pied. / Mountain Ultra Marathon is causing many biomechanical, physiological, neuromuscular, postural and psychological alterations which can lead to certain injuries. However, there are few studies has been focused on the feet. In this context, we conducted three original studies. The first one, performed with 10 runners has shown that the front feet width and the plantar pressure under the forefoot has increased from the mid-distance of a 170km ultra-trail race (UTMB®). The overpressure under the forefoot is due to the forward displacement of the center of pressure which may increase the risk of stress fracture of the metatarsals. These changes that were observed until the end of the competition are probably related to the increase of muscular fatigue of the subjects. In opposition of these changes, we proposed to use moulded orthopaedic insoles that comprising a metatarsal retro-capital bar (MRCB) placed behind the metatarsal heads. The second study carried out in 48 runners has shown that this MRCB element allows to reduce the plantar pressures under the front feet during the standing support by moving backward the center of pressure, and also the hip, the shoulders and the head. The objective of the third study was to evaluate the immediate, short-term (after 4 weeks) and medium-term (after 12 weeks) effect of wearing MRCB insoles on plantar pressure distribution and joint kinematics during running with 10 runners. A similar control group of equal size used during the same period of training moulded insoles without orthopaedic element. This longitudinal study showed that the plantar pressures under the metatarsal heads were reduced immediately with wearing MRCB soles. After 4 weeks, this reduction was accentuated and the ankle's angle of flexion was increased during the stride support. After 12 weeks, the maximum knee extension was increased and most of these changes described aboved were also observed even if the subjects used flat insoles. Any significant changes have been observed in the control group whatever the test period. Regard to these results, we can advise long-distance runners that suffer of pain in the forefoot region to choose slightly larger shoes and to use MRCB orthopaedic insoles to reduce pressure under the forefoot.

Trabecular bone forms the internal scaffolding of most bones, and consists of a microscopic lattice-like structure of interconnected bony struts. Experimental work has demonstrated that trabecular bone adapts its structural rigidity and orientation in response to the strains placed upon the skeleton during life, a concept popularly known as “Wolff’s Law” or “bone functional adaptation”. Anthropological work has focused on correlating variation in primate trabecular bone to locomotor and masticatory function, to provide a context for the interpretation of fossil morphology. However, intraspecies variation and its underlying mechanisms are still poorly understood. In this thesis, variation in trabecular bone structure is examined in the human foot in four archaeological populations. The aim is to tease apart the factors underlying variation in human trabecular microstructure to determine whether it may be a suitable proxy for inferring terrestrial mobility in past populations. μCT scanning is used to image the three-dimensional trabecular structure of the talus, calcaneus, and first metatarsal in samples from four archaeological populations. Trabecular structure is quantified in seventeen volumes of interest placed throughout the foot. Trabecular bone is influenced by a variety of factors including body mass, age, diet, temperature, genetics, sex, and mechanical loading. Before trabecular structure can be used to infer habitual behaviour, the effects of these factors need to be understood and ideally statistically accounted for. Therefore, the effects of variation in bone size and shape, body mass, age, and sex on human trabecular structure are examined in four populations. Significant effects of body mass and age are reported, but little sexual dimorphism was found within populations. Taking these results into account, variation in trabecular structure is compared between archaeological populations that were divided into high and low mobility categories. Results demonstrate that the four populations show similar patterns of trabecular variation throughout the foot, with a signal of terrestrial mobility level superimposed upon it. Terrestrial mobility is associated with greater bone volume fraction and thicker, more widely spaced, and less interconnected trabeculae. Ontogeny of trabecular bone in the human calcaneus is investigated in two archaeological populations in the final chapter of the thesis. Results indicate that calcaneal trabecular bone adapts predictably to changes in loading associated with phases of gait maturation and increases in body mass. This opens the possibility of using trabecular structure to serve as a proxy of neuromuscular development in juvenile hominins. This work demonstrates that trabecular bone may serve as a useful proxy of habitual behaviour in hominin fossils and past populations when all contributing factors are carefully considered and ideally statistically controlled for.

Walking without pain in the toe has a significant impact on a person’s well-being. Human mobility will be impaired in osteoarthritis of the big toe, and pain will occur during walking. By replacing the cartilage or bone injury with an individualised implant, osteochondral injuries to the knee and ankle can be treated. One company that develops and produces these implants together with associated surgical instruments is called Episurf Medical AB. The company can evaluate a lesion and design the individual implant with its associated instrument based on magnetic resonance imaging or computed tomography images. Episurf currently has a production of implants with associated surgical instruments for the knee and ankle but wants to expand further to implants for the metatarsophalangeal joint (MTP joint), commonly named the big toe joint. In order to perform the work process and create the implant and the surgical instruments, Episurf needs qualitative images taken with MRI or CT. Episurf has specific protocols for CT and MRI for imaging the knee and ankle, but no protocol exists yet for the MTP. In this project, CT and MRI have been used to scan the MTP, where various parameters such as foot position, image plane, slice thickness, slice increment and FOV were tested. For CT, different tube currents and tube voltages and their effect on image quality was also tested. In MRI, different sorts of sequences to use when taking pictures of MTP were evaluated. In addition to CT, a scan was also performed with cone-beam computed tomography(CBCT) to see if it could be an additional imaging modality. When evaluating the images for all imaging modalities, Signal to Noise Ratio(SNR), spatial resolution and contrast were considered. For CT, the radiation was evaluated against image quality, and for MRI, the time aspect was evaluated. For images taken with a CT, the parameter setting for the slice thickness should be 0.5-0.8 mm, and the slice increment should be 50% of the slice thickness. As the foot is not a radiation-sensitive region, the radiation can be high. Since the radiation is recommended to be high and the only critical area to evaluate is the big toe, it is enough to include only the forefoot. Finally, the patient’s foot should be in the standing position to have the best possible evaluation opportunities. MRI needs additional tests to find the best relationship between time, SNR, slice increment and slice thickness. More tests also need to be performed for CBCT, where its technology is examined to create an acceptable segmented 3D model, as it was difficult in this project. / Att kunna gå utan smärta i tån har en stor påverkar för en människas välmående. Vid osteorarithis i stortån kommer människans rörlighet att försämras och smärta uppstår vid gången. För att behandla osteokondrala skador för knä och ankeln ersätts skador på brosket eller benet med ett individanpassat implantat. Ett företag som utvecklar och producerar dessa implantat ihop med tillhörande kirurgiska instrument heter Episurf Medical. Baserat på bilder tagna av en MRI eller en CT kan företaget utvärdera en skada och designa det individanpassande implantat med dess tillhörande instrument. Episurf har idag en produktion av implantat med tillhörande kirurgiska instrument för knät och ankeln men har nu velat expandera vidare till implantat för metatarsalphalangen-leden(MTP joint), stortåleden. För att kunna utföra arbetsprocessen och skapa implantatet och de kirurgiska instrumenten behöver Episurf kvalitativa bilder tagna med magnetiskresonanstomografi(MRI) eller datortomografi(CT). För knä och ankeln finns det specifika protokoll för de olika maskinerna skapade för avbildning av knä och ankel, men ännu existerar det inget för MTP. I detta projekt har CT och MRI använts vid skanningar av MTP, där olika parametrar som fotposition, bildplan, snittjockleken och snittöverlapp testas. För CT testades även olika rörström och rörspänning och deras påverkan på bild-kvalitén. Inom MRI utvärderas vilka typer av sekvenser som ska användas när bilder av MTP tas. Förutom CT gjordes även en skanning med kon-datortomografi(CBCT)för att se om den kunde vara en ytterligare avbildnings modalitet. Vid utvärdering avbilderna för alla avbildningsmodaliteter togs Signal to noise ratio, spatiell upplösning och kontrast i beaktande. För CT utvärderades strålningen gentemot bildkvalitet och för MRI utvärderades tidsaspekten. För bilder tagna med en CT bör parameter inställningen för snittjockleken vara 0.5-0.8 mm och snittöverlappet vara 50% av snittjockleken. Då foten inte är en strålkänslig region bör strålningen vara hög. Eftersom strålningen rekommenderas vara hög och det enda intressanta området att utvärdera är stortåbenet, räcker det med att endast inkludera framfoten. Slutligen bör patientens fot vara i stående position för att få så bra utvärderings möjligheter som möjligt. För MRI behöver ytterligare tester för att finna den bästa relationen mellan tid, SNR och snitt tjocklek. Fler tester behöver också utföras för CBCT där dess teknik undersöks, detta för att kunna skapa bra bilder att 3D-segmentera då det var svårt i detta projekt.