11 research outputs found
3D-printing techniques in a medical setting : a systematic literature review
Background: Three-dimensional (3D) printing has numerous applications and has gained much interest in the medical world. The constantly improving quality of 3D-printing applications has contributed to their increased use on patients. This paper summarizes the literature on surgical 3D-printing applications used on patients, with a focus on reported clinical and economic outcomes.
Methods: Three major literature databases were screened for case series (more than three cases described in the same study) and trials of surgical applications of 3D printing in humans.
Results: 227 surgical papers were analyzed and summarized using an evidence table. The papers described the use of 3D printing for surgical guides, anatomical models, and custom implants. 3D printing is used in multiple surgical domains, such as orthopedics, maxillofacial surgery, cranial surgery, and spinal surgery. In general, the advantages of 3D-printed parts are said to include reduced surgical time, improved medical outcome, and decreased radiation exposure. The costs of printing and additional scans generally increase the overall cost of the procedure.
Conclusion: 3D printing is well integrated in surgical practice and research. Applications vary from anatomical models mainly intended for surgical planning to surgical guides and implants. Our research suggests that there are several advantages to 3D- printed applications, but that further research is needed to determine whether the increased intervention costs can be balanced with the observable advantages of this new technology. There is a need for a formal cost-effectiveness analysis
3D-printed patient specific instruments for corrective osteotomies of the lower extremity
3D-printing has become a promising adjunct in orthopedic surgery over the past years. A significant drop in costs and increased availability of the required hardware and software needed for using the technique, have resulted in a relatively fast adaptation of 3D-printing techniques for various indications. In this review, the role of 3D-printing for deformity corrections of the lower extremity is described.</p
Exploring New Therapeutic Strategies for Osteoarthritis: From Genetic Manipulation of Skeletal Tissues to Chemically-modified Synthetic Hydrogels
Osteoarthritis (OA), a degenerative disease of articular joints, is the leading cause of chronic disability in the US and affects more than a third of adults over 65 years old. Due to the obesity epidemic and an aging population, the prevalence of OA is expected to rise in both young and old adults. There are no disease modifying OA drugs. Therefore, providing any treatment options that delay the onset or progression of OA is highly desirable. The scope of this dissertation examines two different strategies to promote translational therapies for OA. The first approach investigated whether Smad ubiquitin regulatory factor 2 (Smurf2), an E3 ubiquitin ligase, could be a potential therapeutic target for OA. The second approach examined the incorporation of small chemical residues to enhance the physical and bioactivity of a bioinert scaffold for cartilage tissue repair.
Overexpression of Smurf2 in chondrocytes was shown to accelerate spontaneous OA development in mice. We hypothesized that reduced Smurf2 expression could slow the progression of OA and enhance the performance of cells for cartilage repair. By performing surgical destabilization of the medial meniscus (DMM) on Smurf2-deficient mice, loss of Smurf2 was shown to mitigate OA changes in young mice but this protection diminished in older mice. Assessment of Smurf2-deficient chondrocytes in vitro revealed an upregulation of chondrogenic genes compared to wild-type; however, these differences were not seen at the protein level, deterring its potential use for cell-based therapies. During the course of this study, new insights about how age and sex affects different joint compartments in response to DMM surgery were also uncovered. These results broadened existing understanding of DMM-induced OA in mice but also questioned the validity of such a model to identify disease modifying targets that are translatable to OA in humans with advanced age.
Due to a lack of innate repair mechanisms in cartilage, damage to cartilage increases the risk of developing OA early. Tissue engineering provides a unique strategy for repairing damaged cartilage by delivering cells in a well-controlled environment that can promote the formation of neotissue. We hypothesized that synthetic chemical residues could enhance the mechanical properties of a bioinert scaffold and promote matrix production of encapsulated chondrocytes. Covalent incorporation of small anionic or zwitterionic chemical residues in a polyethylene glycol-based hydrogel improved its stiffness and resistance to fluid flow, however, the resulting physical environment can also exert a dominant negative effect on matrix production of encapsulated chondrocytes. These results suggest that modulating the biosynthesis of chondrocytes with biochemical signals requires a concurrent reduction in any conflicting mechanotransduction signaling, emphasizing the importance of a degradable system to promote new cartilage formation.
In summary, this dissertation establishes Smurf2 as a modulator of OA progression but implies that other factors such as age or protein(s) with redundant Smurf2 functions may play a role in limiting its effect as a therapeutic target. This work also reveals fundamental biology about how chondrocytes behave in response to physical and chemical cues in their microenvironment, which will aid in the design of better scaffolds for cartilage tissue engineering
The value of medical 3D printing : hope versus hype
3D printing has been growing fast in the medical field. While preliminary clinical results have been reported in the literature, it’s health economic value has not been analyzed yet. Medical 3D printing has found its main applications in surgery; especially orthopedics and reconstructive surgery. Its applications rage from anatomic models to surgical guides and implants. All of these can be seen as consecutive levels of integration. While papers often report improved clinical results, a great accuracy and an acceptable price, few of these are backed with numbers.
We performed 3 health economic analyses using Markov models using a payer perspective on each of these 3 levels of integration.
As a first level, we analyzed the impact of using anatomic models as a tool for surgical planning in congenital heart diseases for 9 different procedures. Results varied from not being cost effective for atrial septum defects, to being highly cost-effective in highly complex procedures such as a Norwood repair.
Second, we analyzed the already well integrated use of surgical guides for primary total knee arthroplasty using Belgian registry data. The database approach showed an significantly reduced revision rate in the group using custom guides compared to the conventional approach. The Markov models showed the technology to be cost-effective if CT-based guides are used. At last, we analyzed the use of custom 3D printed acetabular implants for revision surgery in patients with acetabular defects compared to non-3D printed custom implants. The 3D printed implants showed to be cost effective, especially in younger patients.
The final chapter gives an overview of the pitfalls encountered during these preliminary analyses and gives a glance at possible solutions to allow better analysis and faster adoption of medical innovations
Patient-Specific Implants in Musculoskeletal (Orthopedic) Surgery
Most of the treatments in medicine are patient specific, aren’t they? So why should we bother with individualizing implants if we adapt our therapy to patients anyway? Looking at the neighboring field of oncologic treatment, you would not question the fact that individualization of tumor therapy with personalized antibodies has led to the thriving of this field in terms of success in patient survival and positive responses to alternatives for conventional treatments. Regarding the latest cutting-edge developments in orthopedic surgery and biotechnology, including new imaging techniques and 3D-printing of bone substitutes as well as implants, we do have an armamentarium available to stimulate the race for innovation in medicine. This Special Issue of Journal of Personalized Medicine will gather all relevant new and developed techniques already in clinical practice. Examples include the developments in revision arthroplasty and tumor (pelvic replacement) surgery to recreate individual defects, individualized implants for primary arthroplasty to establish physiological joint kinematics, and personalized implants in fracture treatment, to name but a few
Plasma rich in growth factors to treat Knee Osteoarthritis
188 p.En la tesis titulada Plasma Rich in Growth Factors to treat knee osteoarthritis se exponen 4 trabajosexperimentales basados en el uso del Plasma rico en factores de crecimiento. Los objetivos específicos delos trabajos realizados son los siguientes:1. Validar las inyecciones intraarticulares de PRP como un tratamiento seguro y eficaz para la artrosisde rodilla.2. Evaluar una nueva vía para tratar la artrosis de rodilla, utilizando como diana la membrana sinovial,la superficie del cartílago articular, el líquido sinovial y el hueso subcondral, y combinandoinfiltraciones intraarticulares e intraóseas de Plasma rico en factores de crecimiento (PRP).3. Explorar la adecuación del Líquido sinovial como fuente de células madre mesenquimales (CMMs)y sus respuestas a los mecanismos bilógicos implicados en los efectos de dos modalidades distintasde tratamiento de PRP en pacientes con artrosis: Inyecciones intraarticulares con la membranasinovial, la superfcicie del cartílago articular y el líquido sinovial como diana, o la combinación deinyecciones intraarticulares e intraóseas, alcanzando por último el hueso subcondral
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
Development of an augmented reality guided computer assisted orthopaedic surgery system
Previously held under moratorium from 1st December 2016 until 1st December 2021.This body of work documents the developed of a proof of concept augmented reality
guided computer assisted orthopaedic surgery system – ARgCAOS.
After initial investigation a visible-spectrum single camera tool-mounted tracking
system based upon fiducial planar markers was implemented. The use of
visible-spectrum cameras, as opposed to the infra-red cameras typically used by
surgical tracking systems, allowed the captured image to be streamed to a display in
an intelligible fashion. The tracking information defined the location of physical
objects relative to the camera. Therefore, this information allowed virtual models to
be overlaid onto the camera image. This produced a convincing augmented
experience, whereby the virtual objects appeared to be within the physical world,
moving with both the camera and markers as expected of physical objects.
Analysis of the first generation system identified both accuracy and graphical
inadequacies, prompting the development of a second generation system. This too
was based upon a tool-mounted fiducial marker system, and improved performance
to near-millimetre probing accuracy. A resection system was incorporated into the
system, and utilising the tracking information controlled resection was performed,
producing sub-millimetre accuracies.
Several complications resulted from the tool-mounted approach. Therefore, a third
generation system was developed. This final generation deployed a stereoscopic
visible-spectrum camera system affixed to a head-mounted display worn by the user.
The system allowed the augmentation of the natural view of the user, providing
convincing and immersive three dimensional augmented guidance, with probing and
resection accuracies of 0.55±0.04 and 0.34±0.04 mm, respectively.This body of work documents the developed of a proof of concept augmented reality
guided computer assisted orthopaedic surgery system – ARgCAOS.
After initial investigation a visible-spectrum single camera tool-mounted tracking
system based upon fiducial planar markers was implemented. The use of
visible-spectrum cameras, as opposed to the infra-red cameras typically used by
surgical tracking systems, allowed the captured image to be streamed to a display in
an intelligible fashion. The tracking information defined the location of physical
objects relative to the camera. Therefore, this information allowed virtual models to
be overlaid onto the camera image. This produced a convincing augmented
experience, whereby the virtual objects appeared to be within the physical world,
moving with both the camera and markers as expected of physical objects.
Analysis of the first generation system identified both accuracy and graphical
inadequacies, prompting the development of a second generation system. This too
was based upon a tool-mounted fiducial marker system, and improved performance
to near-millimetre probing accuracy. A resection system was incorporated into the
system, and utilising the tracking information controlled resection was performed,
producing sub-millimetre accuracies.
Several complications resulted from the tool-mounted approach. Therefore, a third
generation system was developed. This final generation deployed a stereoscopic
visible-spectrum camera system affixed to a head-mounted display worn by the user.
The system allowed the augmentation of the natural view of the user, providing
convincing and immersive three dimensional augmented guidance, with probing and
resection accuracies of 0.55±0.04 and 0.34±0.04 mm, respectively