141 research outputs found
Modeling and Simulation in Engineering
This book provides an open platform to establish and share knowledge developed by scholars, scientists, and engineers from all over the world, about various applications of the modeling and simulation in the design process of products, in various engineering fields. The book consists of 12 chapters arranged in two sections (3D Modeling and Virtual Prototyping), reflecting the multidimensionality of applications related to modeling and simulation. Some of the most recent modeling and simulation techniques, as well as some of the most accurate and sophisticated software in treating complex systems, are applied. All the original contributions in this book are jointed by the basic principle of a successful modeling and simulation process: as complex as necessary, and as simple as possible. The idea is to manipulate the simplifying assumptions in a way that reduces the complexity of the model (in order to make a real-time simulation), but without altering the precision of the results
A Computational Study of the Kinematics of Femoroacetabular Morphology During A Sit-to-Stand Transfer
Computational modeling in the field of biomechanics is becoming increasingly popular and successful in practice for its ability to predict function and provide information that would otherwise be unobtainable. Through the application of these new and constantly improving methods, kinematics and joint contact characteristics in pathological conditions of femoroacetabular impingement (FAI) and total hip arthroplasty (THA) were studied using a lower extremity computational model. Patients presenting with FAI exhibit abnormal contact between the femoral neck and acetabular rim leading to surrounding tissue damage in daily use. THA is the replacement of both the proximal femur and acetabular region of the pelvis and is the most common surgical intervention for degenerative hip disorders. A combination of rigid osteoarticular anatomy and force vectors representing soft tissue structures were used in developing this model. Kinematics produced by healthy models were formally validated with experimental data from Burnfield et al. This healthy model was then modified to emulate the desired morphology of FAI and a THA procedure with a range of combined version (CV) angles. All soft tissue structures were maintained constant for each subsequent model. Data gathered from these models did not provide any significant differences between the kinematics of healthy and FAI but did show a large amount of variation in all THA kinematics including incidents of dislocation with cases of lower CV angles. With the results of these computational studies performed with this model, an increased understanding of hip morphology with regards to STS has been achieved
Hip deformities and femoroacetabular impingement
RESUMO: Conceptualmente, a conservação de uma estrutura anatómica é mais benéfica do que a sua
substituição. No caso das articulações humanas, este conceito é particularmente importante face
aos múltiplos problemas, ainda não resolvidos, relacionados com próteses e materiais usados na
cirurgia ortopédica. Na articulação coxofemoral, o conceito de preservação, melhorando os
parâmetros biomecânicos, assume uma complexidade técnica acrescida maioritariamente pelo
facto de a circulação epifisária do fémur ser intra-articular e dada a proximidade de importantes
estruturas neurovasculares.
O conflito femoroacetabular (CFA) e a displasia acetabular no adulto jovem, são duas entidades
patológicas comuns embora com múltiplas áreas ainda por investigar. A displasia infantil, não
diagnosticada e não tratada, pode originar displasia acetabular residual na idade adulta e consequente sintomatologia e limitação funcional. O diagnóstico de CFA no adulto é baseado em
critérios clínicos e radiográficos. Clinicamente apresenta-se igualmente com dor e limitação
funcional. Radiologicamente, dois subtipos de CFA são habitualmente reconhecidos, o tipo
Cam (mecanismo patológico decorrente de asfericidade femoral) e o tipo Pincer (por hipercobertura acetabular). Embora com padrões diferentes de envolvimento articular, os dois mecanismos de conflito condicionam dor, lesão estrutural do labrum e condropatia.
Atualmente, a morfologia Cam é considerada como um dos principais fatores de risco morfológico que contribuem para o desenvolvimento de osteoartrose precoce da coxofemoral, eventualmente com necessidade de recurso a prótese total da anca.
Apesar de a investigação inicial na área da cirurgia conservadora da anca ter documentado bons
resultados cirúrgicos, atualmente a controvérsia é francamente superior ao consenso relativamente à melhor abordagem diagnóstica e terapêutica.
Caracteristicamente, apesar de em muitos casos os achados clínicos e radiológicos serem inequívocos para o diagnóstico de CFA, um número substancial de doentes apresenta achados frustes
ou equívocos. Por outro lado, múltiplos estudos descreveram uma alta prevalência de morfologia
compatível com CFA na população adulta e em indivíduos saudáveis assintomáticos. Atualmente,
não existe uma ferramenta de imagem ideal que facilite a alocação fidedigna de todos os doentes a um grupo patológico específico ou, por outro lado, exclua com confiança o diagnóstico de
conflito. No entanto, os parâmetros de imagem podem ser utilizados para analisar e descrever as
diferentes características morfológicas da anca e adicionalmente confirmar o diagnóstico de CFA.
Esta tese enfoca, por um lado, a avaliação da morfologia coxofemoral em diferentes populações, investigando quais articulações estão mais predispostas ao desenvolvimento de sintomas e,
por outro, os resultados do tratamento cirúrgico de uma coorte com o diagnóstico de CFA tipo
Cam. Especificamente, a investigação efetuada: 1) examinou características morfológicas específicas da coxofemoral em diferentes populações (sintomáticas ou não sintomáticas); 2) desenhou
um modelo estatístico baseado em preditores anatómicos no sentido de estabelecer as articulações em risco de desenvolvimento sintomático, incorporando geometrias articulares específicas
e parâmetros espinhopélvicos; e 3) analisou os resultados de terapêutica cirúrgica numa coorte
de doentes com o diagnóstico CFA tipo Cam.
Durante a progressão clínica na área da imagiologia e nesta área patológica em particular,
apercebemo-nos da existência de múltiplas lacunas de conhecimento que procurámos colmatar
com a investigação agora publicada e descrita nesta tese. A sistematização por capítulos reflete
precisamente a necessidade de abordar a questão em áreas de conhecimento, simultaneamente
distintas e complementares.
Os seis capítulos desta tese abrangem o espectro clínico desde o diagnóstico até ao tratamento
da anca jovem. De modo a apresentar os objetivos desta tese numa sequência lógica, desde a
anatomia geral até à morfologia e tratamento específicos do CFA, a análise da anca assintomática
será descrita em primeiro lugar seguida pela análise da relação anatomoclínica entre morfologia
articular e sintomas. Por último será abordada a terapêutica do doente sintomático.
Na PARTE I, apresentamos os tópicos essenciais para compreender a abrangência do espectro da presente tese, designadamente a relevância e a contemporaneidade do tema “CFA”
e adicionalmente o enquadramento anatómico, morfológico e vascular desta articulação.
O Capítulo 1 é dedicado ao desenvolvimento e morfogénese da anca. No Capítulo 2,
sublinhamos a importância e o papel da imagem através de uma revisão enfocada nas perspetivas atuais e futuras sobre este tópico (Artigo I). No Capítulo 3, realizamos uma revisão
sistemática da literatura no sentido de descrever o estado da arte com foco na prevalência
da morfologia de CFA em populações assintomáticas e sintomáticas. Este capítulo destaca as
múltiplas lacunas de conhecimento relativas ao papel da morfologia da articulação coxofemoral na patogénese do CFA (Artigo II).
Com base nesta parte introdutória, abordamos seguidamente os objetivos da presente tese,
gerais e específicos, na PARTE II.Na PARTE III, descrevemos o corpo da investigação clínica original efetuada. O Capítulo 4
é dedicado à caracterização detalhada da morfologia da anca, designadamente óssea e vascular. A morfologia coxofemoral foi quantificada utilizando software com capacidade de
semi-automatização analítica, permitindo estudar a prevalência e relação entre as diferentes
morfologias articulares e o género, dominância e simetria articular (Artigo III). A morfologia
Cam foi ainda alvo de caracterização mais aprofundada, através do desenvolvimento de um
novo parâmetro quantitativo com potencialidade diagnóstica e de planeamento cirúrgico/
/prognóstico, primariamente testado numa coorte assintomática (Artigo IV) e seguidamente
também em doentes com indicação cirúrgica (Artigo V).
Na nossa atividade clínica diária apreciámos a necessidade urgente de melhor caracterizar a
topografia da deformidade Cam e a respetiva relação com as artérias nutritivas da epífise femoral.
A impressão clínica referida sugeria que a morfologia Cam frequentemente se estendia posteriormente ao quadrante póstero-superior, intersectando a região retinacular vascular. No entanto,
por imagem a natureza arterial destas estruturas nunca havia sido confirmada. Por esta razão,
a importância do parâmetro mencionado foi sublinhada e comprovada no estudo cadavérico
com avaliação topográfica vascular do fémur proximal (Artigo VI).
No Capítulo 5 testámos múltiplos parâmetros imagiológicos e respetivas variações/relações
com diferentes morfologias coxofemorais, no sentido de identificar as articulações com risco
clínico aumentado de desenvolvimento sintomático. Para este fim efetuámos estudos baseados
em computação avançada com modelação estatística (Artigo VII) e também em ressonância
magnética (RM) tridimensional (Artigo VIII).
O Capítulo 6 descreve as opções de tratamento (Artigo IX) e os resultados clínicos num estudo
clínico de uma coorte com follow-up mínimo de 2 anos, comparando a abordagem cirúrgica
aberta e artroscópica (Artigo X).
Os resultados dos diferentes capítulos estão sumarizados na PARTE IV, onde apresentamos a síntese geral, a discussão crítica dos resultados obtidos à luz da literatura atual e finalmente as conclusões relevantes. As oportunidades futuras de investigação são igualmente abordadas neste capítulo.
Em resumo o trabalho constante da presente tese sugere:
Primeiro, que a avaliação imagiológica detalhada da morfologia coxofemoral é essencial
no sentido de compreender aprofundadamente não só a própria articulação como também
a morfologia pélvica (Artigo I).
Segundo, paradoxalmente, a definição clínica de um caso patológico e das diferentes
entidades relacionadas, é ainda inexistente. Os parâmetros quantitativos e qualitativos que
comummente estão associados com CFA tipo Pincer e Cam são francamente frequentes
em diferentes populações (sintomáticas e assintomáticas) (Artigo II).Terceiro, em populações assintomáticas adultas, os intervalos de referência específicos
para os parâmetros quantitativos associados a morfologia de CFA e displasia são mais latos
e com limites superiores mais elevados do que os atualmente utilizados na prática clínica (Artigo III). A morfologia femoral bem como os epicentros/magnitudes das deformidades Cam são específicos de género, observando-se maiores valores de ângulo alfa
e ómega em indivíduos do sexo masculino (Artigo IV).
Quarto, é frequente a interseção entre a extensão póstero-superior da deformidade Cam
e a convergência epifisária das estruturas vasculares retinaculares observadas em RM, aspetos que se revestem de primordial importância no planeamento cirúrgico. Adicionalmente
a extensão radial da deformidade Cam (ângulo ómega) está significativamente mais relacionada com a sintomatologia clínica pré-cirúrgica do que o parâmetro mais comummente
utilizado na prática clínica (ângulo alfa) (Artigo V). A origem das estruturas vasculares
observadas por RM na prega retinacular é inequivocamente arterial, sendo que abrange
uma extensão mais anterior do que classicamente assumido (Artigo VI).
Quinto, as geometrias ovalares (em detrimento das morfologias esféricas e elipsoides)
são melhor representativas de ambas as superfícies articulares da coxofemoral, designadamente do fémur e acetábulo, bem como das ancas sintomáticas que clinicamente exibem
sinais de CFA (Pincer, Cam e misto) (Artigo VII). Indivíduos com maiores deformidades Cam, aspetos de hipocobertura acetabular e acentuação da anteflexão pélvica apresentam uma maior probabilidade de desenvolverem sintomas articulares (Artigo VIII).
Esta observação é crítica, dado que fornece, na prática clínica, informação essencial acerca
da potencial predisposição para fenómenos de exacerbação sintomática futura, permitindo
desta forma instituição de medidas terapêuticas/preventivas adequadas. Na perspetiva do
doente, um diagnóstico precoce e preciso, pode conceptualmente prevenir, numa primeira fase, alterações condropáticas articulares e, numa segunda instância, progressão para
artrose estabelecida.
Sexto, documentamos resultados clínicos e funcionais significativamente favoráveis quando
comparamos a abordagem artroscópica e aberta no tratamento cirúrgico da deformidade
Cam, sendo de observar que o género feminino está associado a menor score funcional na
avaliação pré-operatória (Artigos IX e X).
Futuramente, a imagiologia e a cirurgia conservadora da anca irão desenvolver-se conjuntamente e em paralelo com novos e maiores desafios. A descrição de novos parâmetros analíticos
para avaliação da patoanatomia coxofemoral, associada à inovação tecnológica crescente e à
implementação da inteligência artificial, impõem uma evolução clínica oposta à assunção de
classificações patológicas demasiadamente simplistas. Nesse sentido a existência de guidelines de diagnóstico e terapêutica mais efetivas e baseadas na evidência, que nos levem além da pura diferenciação entre CFA e displasia, são urgentes. A história natural das deformidades Cam e Pincer,
sintomáticas ou assintomáticas, é ainda grandemente desconhecida, assumindo-se como uma
área determinante de investigação no que concerne ao diagnóstico, terapêutica e prognóstico.ABSTRACT: Conceptually, the preservation of a human anatomical structure makes more sense than its
replacement. This concept is even more striking in the case of human joints due to the multitude of unsolved problems related to implants used in orthopaedic surgery. With respect to
the hip, joint preservation assumes an increased technical complexity when compared to other
joints; this is due to two main reasons: the intra-articular epiphyseal circulation of the femur and
the proximity of large neurovascular structures.
Femoroacetabular impingement (FAI) and acetabular dysplasia (DHD) in young adults are two
common but poorly characterised pathological entities. If undiagnosed and untreated, dysplasia in
childhood may lead to residual DHD in young adults, as diagnosed on radiographs, and may also
give rise to symptoms such as hip pain and restricted range of motion. The diagnosis of FAI in
adults is based on clinical and imaging criteria. The most frequently noticed symptoms of FAI
include hip pain and restricted function. Radiologically, two main subtypes of FAI are recognised:
The Cam-type, with the pathoanatomical mechanism located on the femoral side, and the Pincertype on the acetabular side. Although with different pathological patterns, both types cause pain
and articular damage of the labrum and cartilage. While Cam-type FAI is believed to be a major
contributing factor to the early onset of hip osteoarthritis (OA), which eventually requires a total
hip replacement, the relationship of other shapes and morphologies with OA are still under debate.
Despite the initial promising reports on outcomes following surgical management of these conditions, the best approach to diagnose and manage them still remains controversial. Although
for some patients there are unambiguous clinical and imaging findings of FAI, for a substantial
number of patients there are minimal or intermediate findings. Moreover, several studies have
reported a high prevalence of FAI morphology among the “normal” population and in asymptomatic healthy individuals. At present, there is no adequate imaging tool to facilitate the reliable
allocation of all patients into the correct diagnostic group or to confidently rule out diagnosis.
However, imaging parameters can be used to describe different hip morphological characteristics and additionally confirm or preclude the diagnosis of FAI.This thesis focuses on assessing hip morphology in different populations by investigating which
specific joints are more prone to developing symptoms and by evaluating treatment outcomes
of a FAI cohort. Specifically, this research concentrates on the following: 1) examining population-specific (symptomatic and non-symptomatic) characteristics of hip morphology; 2) developing an anatomic-based model to establish “at-risk” hip joints, incorporating subject-specific hip
geometries and spinopelvic parameters and 3) investigating treatment outcomes in a Cam-type
FAI cohort.
In our clinical progression in imaging and in this particular area of pathology, we became aware
of the existence of several gaps that we sought to fill with the now published research hereby
described. The systematisation by chapters precisely reflects the need to address the issue in
simultaneously distinct and complementary areas of knowledge.
This thesis consists of six chapters, which cover the entire spectrum from the diagnosis to treatment of the young hip. To present the aims of this thesis in a sequential manner from general
morphology to more specific FAI-related topics, the analysis of the asymptomatic hip will be
presented first, followed by how joint morphology is associated with symptoms and, finally,
will conclude with treatment.
In PART I, we introduce the topics that are relevant to understand the full scope of our thesis;
we aim to accomplish this by addressing the relevance and contemporariness of the “FAI” theme
and by describing the general and vascular anatomy of the hip. Chapter 1 is devoted to hip
development and morphogenesis. In Chapter 2, we address the importance of imaging by conducting a thorough review of current and future perspectives on this topic (Paper I). In Chapter 3,
we perform a systematic review of the literature to write a state-of-the-art overview, focussing
on asymptomatic and symptomatic FAI morphology prevalence and highlighting the multiple
gaps in knowledge regarding the role of hip morphology in the pathogenesis of FAI (Paper II).
Building on the first part, we address the rationale and aims of this thesis in PART II.
In PART III, we describe the original research that was performed and published. Chapter 4
focusses on the detailed characterisation of hip morphology, both osseous and vascular. Bony
hip morphology was quantified using a semi-automated software, which allows to robustly study
in detail shape variants in an asymptomatic population and their relationship with sex, side and
limb dominance (Paper III). Cam morphology was further defined by developing a novel quantitative parameter, with diagnostic and treatment planning capabilities using a cohort of both
asymptomatic individuals (Paper IV) and patients undergoing surgery (Paper V). Moreover, we
felt the need to better characterise the topography of the deformity and its relationship with
the nourishing arteries of the femoral head, as Cam morphology frequently has a posterior
a bstr extension that overlaps the retinacular vascular structures. However, its arterial origin has never
been described or confirmed in the literature. For this reason, the importance of the aforementioned parameter has been outlined by the cadaveric arterial topographic study of the proximal
femur (Paper VI). In Chapter 5, we test multiple parameters and their associated shape variants
to detect which ones allow identifying a risk-increased joint in various populations. To this end,
we use both advanced computing for shape modelling (Paper VII) and three dimensional (3D)
magnetic resonance imaging (MRI) (Paper VIII). Chapter 6 describes the various treatment
options (Paper IX) and outcomes in a cohort clinical study, comparing open surgery with
arthroscopic surgery in terms of treating Cam deformities (Paper X).
The results of the aforementioned chapters are summarised in PART IV, presenting the general
synthesis, discussing the results in the light of current literature and detailing the conclusions of
this thesis. The scope of potential future research within this field is also presented in this chapter.
In brief, this thesis suggests the following:
First, detailed imaging assessment of hip morphology is paramount to better understanding both the hip joint and pelvic morphology (Paper I).
Second, the case definitions of different morphologies and clinical entities are missing as
far as FAI and related disorders are concerned. Qualitative and quantitative radiographic
findings thought to be associated with Cam- and Pincer-type FAI, as well as the coexistence between them, are quite common among different populations (Paper II).
Third, in adult asymptomatic populations, sex-specific reference intervals for hip measurements for DHD and FAI morphology are wider than currently accepted values (Paper III).
Moreover, femoral morphology with distinct Cam magnitudes and epicentres is also
sex-specific, with higher mean alpha angle (α°) and omega angle (Ω°) values seen in males
(Paper IV).
Forth, Cam deformity frequently overlaps with the retinacular vascular structures seen
in an MRI; this finding has practical surgical relevance. Additionally, the radial extension
of the Cam deformity (Ω°) is more significantly associated with the patients’ symptoms
prior to surgery than the α° (paper V). The origin of the vascular structures seen in the
retinacular fold is unequivocally arterial in nature, and these structures have a more anterior
distribution than classically assumed (Paper VI).
Fifth, ovoid geometries are more representative of both articular surfaces of the hip joint as
well as of Cam, Pincer and mixed impinged hips when compared to spherical or ellipsoidal shapes (Paper VII). Individuals with larger Cam deformities, decreased acetabular coverage
and increased pelvic anteflexion are more likely to experience hip symptoms (Paper VIII).
This provides clinicians with indications of how the pathology exacerbates, allowing them
to perform the correct clinical assessments and proceed with the correct form of care.
From a patient’s perspective, an early and accurate diagnosis could prevent cartilage degradation and progression to OA.
Sixth, similar outcomes and significant functional improvement are observed when comparing open and arthroscopic surgery in the treatment of Cam deformities (follow-up
time of two years). It should be noted that the female gender was associated with poor hip
function in the preoperative evaluation (papers IX and X).
Looking ahead, imaging and hip preserving surgery (HPS) will evolve hand-in-hand in the
face of new and greater challenges. The increasing number of analytic parameters describing
hip joint pathomorphologies as well as new sophisticated 3D imaging-analysis together with
emerging artificial intelligence-based technologies have transported us beyond simple classification systems. Moreover, more reliable diagnostic and treatment guidelines that go beyond
differentiation into pure FAI and dysplasia are paramount. The largely unknown natural course
of both hips with symptomatic FAI and asymptomatic individuals continues to present research
opportunities as far as diagnosis, treatment and prognosis are concerned
Mesenchymal Stem Cell Constructs for Repair of Focal Cartilage Defects in an Ovine Model
Focal cartilage defects (FCD) of the knee joint remain a difficult area of treatment for orthopaedic surgeons, as they often progress to generalized osteoarthritis (OA). Osteochondral autograft transfer (OAT) to the damaged cartilage area has shown promise, but this has been associated with pain and bleeding at the site of graft harvest. The use of mesenchymal stem cells (MSCs) in a matrix to regenerate articular cartilage has been proposed. This work describes a prospective case-control series comparing OAT with a novel, MSC-seeded scaffold graft in the stifle joints of healthy merino sheep. The triphasic grafts were composed of a beta-tricalcium phosphate osseous phase, an intermediate activated plasma phase and a collagen I hydrogel cartilage phase.
The osseous and cartilage phases were seeded with autologous MSCs.
All sheep underwent creation of a full-thickness, 4.0 mm diameter FCD (n=20) followed by six weeks of unrestricted activity, allowing the defects to degenerate naturally. At six weeks, half of the lesions were treated with OAT and half with the triphasic engineered grafts.
At 6-month and 12-month follow-up, no significant differences were noted between groups with regard to overall histological scores. Macroscopic and biomechanical analysis at 12 months showed no significant differences between groups. In summary, autologous MSC-seeded implants showed comparable repair quality to OAT without the associated donor site morbidity
Fixation of Unicondylar Knee Prostheses
There is increasing use of Unicondylar or Unicompartmental Knee Replacements (UKR), especially following publication of good survival data and a trend towards ‘minimally invasive surgery’. The UKR preserves one of the femoral condyles and its meniscus, plus both of the cruciate ligaments. Therefore, the knee functions more normally following UKR than after Total Knee Replacement (TKR). However, the odds for failure of the UKR are higher than the TKR, and a principal reason is loosening of the tibial and femoral components. There is a need for the development of more reliable UKR fixation designs.
The overall aim of this research was to understand fixation of UKR and make recommendations for improvement to designers and surgeons. Since the Oxford mobile-bearing UKR is most widely used in the UK, it was used as the benchmark in this study.
To assess initial fixation, in-vitro bone-constructs were prepared from ten cadavers implanted with the Oxford mobile-bearing UKR and tested for bone strain and bone-implant interface motion with the implants fixed using first cementless and then cemented methods. Cementless fixation produced higher proximal tibia strain and bone-implant displacement than cemented fixation. Peak bone strain increased with reduced bone density, such that the lowest density specimen fractured when implanted with the cementless UKR.
To assess long-term fixation, an in-vivo prospective follow-up study of 11 Oxford UKR patients was developed and conducted for one-year, taking measurements of bone density using Dual X-Ray Absorptiometry (DXA) scanning. The average bone resorption under the tibial implant was found to be low; while it was higher under the femoral component and very high under the tibial intercondylar eminence. The fixation of the Oxford UKR implant was considered to be adequate at 1-year.
Finite Element (FE) simulation techniques were reviewed and developed to simulate the UKR knee for investigation of bone strain, bone-implant interface micromotion and bone remodelling to assess initial and long-term fixation performance. Computer simulations of the tibiae and femora of 2 patients and 4 cadaveric specimens (obtained from the in-vivo and in-vitro studies) were developed and validated for bone strain, bone-implant interface micromotion and bone remodelling.
Comparative multi-specimen computational studies were conducted to understand how particular design features affected fixation. Good fixation was indicated for cementless UKRs when implanted in dense bone, but bone strains were very high in low density tibia. Cementation of the implants spread the loads more evenly and reduced bone strains. The cementless tibial implant caused less bone resorption (compared to the cemented equivalent) but the difference in the femur was small. Bone resorption was highest at the anterior tibia and posterior to the femoral peg. Bone density was an important factor in the fixation performance of implant design features. Less bulky fixation features reduced bone resorption, provided that the underlying bone was sufficiently dense to maintain bone strains below the failure limit of bone. For patients with dense bone, fixation could be improved with shorter tibial keels and less stiff femoral implants. For patients with low density bone, fixation could be improved with cementation and bone resection that avoids creating stress-raisers
Annual Research Report, 2010-2011
Annual report of collaborative research projects of Old Dominion University faculty and students in partnership with business, industry and government.https://digitalcommons.odu.edu/or_researchreports/1000/thumbnail.jp
Shape Modelling of Bones: Application to the Primate Shoulder
The aims of this work were to develop techniques for describing morphological variations
of shoulder bones and to test these on real datasets.
The robust measurement and description of anatomical geometry can provide accu-
rate estimation and better understanding of bone morphology. Feature lines were detected
automatically using crest line techniques and shape information from shoulder bones was
extracted based on the extracted feature lines. Redefinition of local coordinate systems
was proposed utilising the crest line technique.
Three dimensional statistical shape models (SSM) were built for a set of primate
humeri and scapulae. Two types of models were constructed: one incorporated the main-
tained original scale whilst the other used scaled bones. Variations were captured and
quantified by Principal Component Analysis (PCA). The application can be extended
generally to long bones and other complex bones and was also tested on human femora.
Techniques to predict the shape of one bone from its neighbour at a joint were
presented. PCA was used to reduce data dimensionality to a few principal components.
Canonical Correlation Analysis (CCA) and Partial Least Square (PLS) Regression were
applied to explore the linear morphological correlations between the two shoulder bones
and to predict the shape of one segment given the shape of the adjoining segment
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