28 research outputs found
Live Wire Segmentation Tool for Osteophyte Detection in Lumbar Spine X-Ray Images
Computer-assisted vertebra segmentation in x-ray images is a challenging problem. Inter-subject variability and the generally poor contrast of digitized radiograph images contribute to the segmentation difficulty. In this paper, a semi-automated live wire approach is investigated for vertebrae segmentation. The live wire approach integrates initially selected user points with dynamic programming to generate a closed vertebra boundary. In order to assess the degree to which vertebra features are conserved using the live wire technique, convex hull-based features to characterize anterior osteophytes in lumbar vertebrae are determined for live wire and manually segmented vertebrae. Anterior osteophyte discrimination was performed over 405 lumbar vertebrae, 204 abnormal vertebrae with anterior osteophytes and 201 normal vertebrae. A leave-one-out standard back propagation neural network was used for vertebrae segmentation. Experimental results show that manual segmentation yielded slightly better discrimination results than the live wire technique
The safety and efficacy of mesenchymal stem cells for prevention or regeneration of intervertebral disc degeneration: a systematic review
General Posters: abstract no. GP86INTRODUCTION: Mesenchymal stem cells (MSCs) have been used to halt the progression or regenerate the disc with hopes to prevent or treat discogenic back pain. However, the safety and efficacy of the use of MSCs for such treatment in animal and human models at short and long term assessment (i.e. greater than 48 weeks) have not been systematically addressed. This study addressed a systematic review of comparative controlled studies addressing the use of MSCs to that of no treatment/saline for the treatment of disc degeneration. METHODS: Online databases were extensively searched. Controlled trials in animal models and humans were eligible for inclusion. Trial design, MSC characteristics, injection method, disc assessment, outcome intervals, and complication events were assessed. Validity of each study was assessed addressing trial design. Two individuals independently addressed the aforementioned. RESULTS: Twenty-two animal studies were included. No human comparative controlled trials were reported. All three types of MSCs (i.e. derived from bone marrow, synovial and adipose tissue) showed successful inhibition of disc degeneration progression. From three included studies, bone marrow derived MSC showed superior quality of disc repair when compared to other treatments, including TGF-β1, NP bilaminar co-culture and axial distraction regimen. However, osteophyte development was reported in two studies as potential complication of MSC transplantation. CONCLUSIONS: Based on animal models, the current evidence suggests that in the short-term MSC transplantation is safe and effective in halting disc degeneration; however, additional and larger studies are needed to assess the long-term regenerative effects and potential complications. Inconsistency in methodological design and outcome parameters prevent any robust conclusions. In addition, randomized controlled trials in humans are needed to assess the safety and efficacy of such therapy.published_or_final_versio
Book of Abstracts 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and 3rd Conference on Imaging and Visualization
In this edition, the two events will run together as a single conference, highlighting the strong connection with the Taylor & Francis journals: Computer Methods in Biomechanics and Biomedical Engineering (John Middleton and Christopher Jacobs, Eds.) and Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization (JoãoManuel R.S. Tavares, Ed.).
The conference has become a major international meeting on computational biomechanics, imaging andvisualization. In this edition, the main program includes 212 presentations. In addition, sixteen renowned researchers will give plenary keynotes, addressing current challenges in computational biomechanics and biomedical imaging.
In Lisbon, for the first time, a session dedicated to award the winner of the Best Paper in CMBBE Journal will take place.
We believe that CMBBE2018 will have a strong impact on the development of computational biomechanics and biomedical imaging and visualization, identifying emerging areas of research and promoting the collaboration and networking between participants. This impact is evidenced through the well-known research groups, commercial companies and scientific organizations, who continue to support and sponsor the CMBBE meeting
series. In fact, the conference is enriched with five workshops on specific scientific topics and commercial software.info:eu-repo/semantics/draf
Intervertebral Disc Height Loss and Restoration: Outcomes and Implications
This thesis is unified around the theme of disc height loss. Current knowledge in the area of spine research identifies mechanical overload as the culprit for the initiation of injury to the spine. While genetic predispositions may play a factor in the severity of spine degeneration or in the resiliency to applied load, ultimately, injury occurs when a load exceeds a tissue’s tolerance.
Disc height loss has the potential to be a primary factor in the progression of spinal degeneration. For example, disc height has been touted as a major component for the initiation of pathological and degenerative changes to the spine. Pathologic, non-recoverable disc height loss can occur through herniation or endplate fracture and could result in a degenerative cascade of injury that eventually involves the facet joints, narrows nerve root space, and increases stress at adjacent segments. What is not known is the degree to which disc height affects the degenerative cascade; that is, there is no quantitative data outlining the progression of mechanical consequences at adjacent segments or at the injured segment itself during disc height loss. Further, the degree to which restoring disc height, if even possible, will reverse the process of degeneration is not entirely clear. There is data which suggests that nucleus replacement can restore stress distributions within an injured disc, but the extent of repair material survivability is unknown. Finally, clinical categories of measuring spinal degeneration are based on visual cues and features from medical imaging. Understanding the links between joint visual cues and aberrant movement may help to guide clinical practice; researchers will gain greater insight into the mechanical consequences of anatomical features associated with degeneration.
This thesis was comprised of three studies. Study 1 examined the effect of disc height loss and subsequent restoration using an injectable hydrogel on the relative kinematics of a segment with height loss and an adjacent segment. It was found that disc height loss produced an immediate effect, where relative angular displacement was reduced in the segment with height loss and increased in the adjacent segment. Restoring disc height with an injectable hydrogel brought the relative angular displacement of both segments back to their initial values. This study is the first of its kind to examine the immediate effects of disc height loss via loss of nucleus pulposus and restoration. Whether these effects are as clear in-vivo remains to be seen.
Study 2 evaluated the efficacy of a novel repair strategy to restore the mechanical profile of a spine segment with disc height loss initiated via compressive fracture. The strategy employed the use of PMMA injected into the vertebral body to attempt to seal a fracture from above the disc, and an injectable hydrogel to restore disc height. The use of PMMA was found to restore the compressive stiffness of the injured segment to within approximately 20% of its initial value, while the use of the injectable hydrogel restored the sagittal plane rotational stiffness to within approximately 50-80% of its initial value. After further repetitive compression had been applied to the spine segment however, the restorative influence of both interventions was lost in terms of rotational and compressive stiffness. It was found that large cracks in the endplate prevented the hydrogel from being contained and quickly returned the segment back to its injured profile. Future efforts at restoring the disc while maintaining its anatomical structures need better methods of creating a sufficient seal inside the disc to allow it to re-pressurize and sustain the stresses encountered on a daily basis.
Study 3 employed the use of a novel spine tracking algorithm developed as part of this thesis to evaluate sagittal plane cervical spine motion of a series of patient image sequences who had experienced trauma and had a chief complaint related to their neck, head, or shoulders. Some patients had evidence of disc height loss while others did not. Clinical subgroups were created that classified disc height loss as either moderate/severe (3 cases), mild (8 cases), or non-existent (9 cases). When normalized angular displacement of the C5/C6 segment in a group with moderate to severe height loss was compared to the same level in a group with no height loss, there was a statistically significant difference in angular displacement between the two groups (p = 0.004). Angular displacement at C5/C6 was 20.2% ± 2.3% of total measured neck angular displacement in the moderate/severe height loss group compared to 30.6% ± 4.0% of total measured neck angular displacement in the group without height loss. Based on the limited sample size of this study it would appear that disc height loss creates a loss in range of motion. This work has further revealed the heterogeneous nature of individual segmental movement patterns. However, in the group without height loss, there was a systematic trend seen of an increasing angular displacement with descending segmental level. This was not observed in those with moderate to severe disc height loss.
The broad implications of this work are that disc height loss influences spine kinematics, which has implications with respect to further injury propagation through the spinal linkage. Angular displacement of a spine segment appears to be governed by its local stiffness. Restoration of disc height under real injury scenarios is a difficult proposition and any attempts at repair need to sufficiently seal the disc space and prevent extrusion of nucleus pulposus or hydrogel-based implants. We now appreciate the difficulty in this objective. Further, repeating the mechanism of injury will reduce the mechanical effects of the restorative intervention, preventing this is highly important
Pelvic kinematics as confounding factor for cam hip impingement
The purpose of this thesis was to explore a range of biomechanical factors linked to the development of symptoms and potentially early onset hip OA in people with cam hip impingement. This was achieved through shape analysis on 3D bone models (segmented from medical images), and motion analysis performed during walking and squatting. Following ethical approval, kinematic and morphological variables were obtained from 19 pre-operative hip impingement patients and 18 healthy controls, and these were compared between groups. Patients demonstrated reduced neck-shaft-angles (-6.0°, p<.01) and increased anterior pelvic tilt during gait (+3.2°, p=.04) which are thought to predispose to impingement by decreasing the proximity between the cam and acetabular rim and making abutment more likely. The transverse pelvic plane is used to measure pelvic tilt during motion analysis, it is therefore interesting that the angle between the transverse and anterior pelvic plane is increased (+4.6°, p=.03) in patients, emphasising that the interplay between shape and function is a priority for further research. Avoidance of hip extension (-5.9°, p<.01) was also observed, which could be a compensatory mechanism to prevent further damages to the hip. Furthermore, large cams are thought to act as a mechanical constraint and limit rotation movement allowed within the acetabulum, as demonstrated by reduced peak hip internal rotation (during squat, -8.5°, p=.03). Controls were regrouped based on morphology to allow comparison between asymptomatic (CAM-; n=11) and symptomatic (CAM+, n=16) cams. Symptomatic cams have an increased width (+41.4°, p<.01), and start more superiorly (-29.4°, p<.01). Increased sagittal pelvic mobility (e.g. during a squat; -11.2° for CAM+, p<.01) is thought to be protective against hip impingement symptoms, as during high flexion angles the pelvic tilts backwards reducing the risk of abutment. These findings highlight the need to establish thresholds taking confounding factors into account.Open Acces
Spinal stenosis
This thesis describes in detail the clinical spectrum of spinal stenosis
in a series of two hundred and twenty-one patients at the
Nuffield Orthopaedic Centre. It depicts those conditions with which spinal
stenosis may be confused, and other conditions with which it is associated.
Characteristic symptoms and physical signs are reported and the role and
value of different methods of investigation are discussed.
The aetiology and pathogenesis of spinal stenosis is discussed and the
emphasis turned away from absolute measurements of the dimensions of the
bony spinal canal, towards the role of the soft tissues and the dynamic
response of the canal and its neural contents to postural change and loading,
as evidenced by erect flexion and extension radiculography. The spinal
reserve capacity measurement on CT approaches more closely the ideal of
measurement of volumetric disproportion of canal and contents, but it takes
no account of the dynamics of the canal. Magnetic Resonance Imaging may,
in the future, provide the most objective criteria for diagnosis if section
thickness can be reduced.
Experimental spinal stenosis was produced in a group of immature
New Zealand white rabbits. This was induced by sublaminar wiring at three
levels at the age of eight weeks and allowing the animals to grow for
twenty-four months before sacrifice and analysis of the spines. The effect
of sublaminar wiring on the growth and development of the lamina and
spinal canal was analysed using a Kontron Ibas Image Analysis Computer,
and the results described and statistically analysed.
The results of surgery were analysed in detail in a group of seventytwo
patients with spinal stenosis at the Nuffield Orthopaedic Centre. The
long-term results were compared with the initial post-operative result and
two groups were identified: the stable result and the unstable result. The
indications for and results of re-operation were also analysed in a group
of twelve patients. Improved understanding of the aetiology of spinal stenosis has enhanced
surgical management and results. The extent of surgical decompression
must be precisely planned pre-operatively from radiographic and CT studies,
and the surgeon must be able to execute this plan at operation. There is
now no place for exploratory operations. The objective of surgery is
adequate nerve root decompression without spinal de-stabilisation and when
this is achieved, re-operation is redundant
Development of a Decellularized Hydrogel Composite and its Application in a Novel Model of Disc-associated Low Back Pain in Female Sprague Dawley Rats
Chronic low back pain is a global socioeconomic crisis compounded by an absence of reliable, curative treatments. The predominant pathology associated with chronic low back pain is degeneration of intervertebral discs in the lumbar spine. During degeneration, nerves can sprout into the intervertebral disc tissue and be chronically subjected to inflammatory and mechanical stimuli, resulting in pain. Pain arising from the intervertebral disc, or disc-associated pain, is a complex, multi-faceted disorder which necessitates valid animal models to screen therapeutics and study pathomechanisms of pain.
While many research teams have created animal models of disc degeneration, the translation of these platforms to disc-associated pain models has been limited by an absence of chronic pain-like behavior. Further, the few models which measure disc-associated pain-like phenotypes have been established in mice, which are not amenable to surgical treatment procedures due to their small size. This deficiency drives the need for a new model of disc-associated pain where pain-like behavior is measurable and intervertebral discs are large enough for surgical procedures. These criteria promote rats as the optimal platform for a disc-associated model of chronic low back pain.
Herein, a rat model of disc-associated pain is described that displays chronic pain-like behavior, overt disc degeneration, and nerve sprouting in the intervertebral disc. In addition to the model, a novel method for measuring disc degeneration real-time, non-invasively, is delineated which exhibits remarkable precision and accuracy. Finally, a next generation treatment, derived from decellularized, porcine nucleus pulposus tissue is described which is injectable, thermally fibrillogenic, and cytocompatible. In the rat model of disc-associated pain, this biomaterial restores degenerated disc volume and dramatically decreases pain-like behavior.
In summary, this dissertation describes the development of a method for quantifying degeneration real-time, establishes a rat model of disc-associated pain, and successfully treats disc-associated pain in this model with a next-generation biomaterial.
Advisor: Rebecca Wach
Spine Surgery
We are very excited to introduce this new book on spinal surgery, which follows the curriculum of the EUROSPINE basic and advanced diploma courses.
The approach we take is a purely case-based one, in which each case illustrates the concepts surrounding the treatment of a given pathology, including
the uncertainties and problems in decision-making. The readers will notice
that in many instances a lack of evidence for a given treatment exists. So decisions taken are usually not a clearcut matter of black or white, but merely
different shades of gray. Probably in a lot of cases, there is often more than
one option to treat the patient. The authors were asked to convey this message
to the reader, giving him a guidance as what would be accepted within the
mainstream. In addition, the reader is provided with the most updated literature and evidence on the topic.
Most of the authors are teachers in the courses of EUROSPINE or other
national societies with often vast clinical experience and have given their own
perspective and reasoning.
We believe that the readers will profit very much from this variety and
bandwidth of knowledge provided for them in the individual chapters. We
have given the authors extensive liberty as to what they consider the best
solution for their case. It is thus a representative picture of what is considered
standard of care for spine pathologies in Europe.
We hope that this book will be an ideal complement for trainees to the
courses they take.
Munich, Germany Bernhard Meyer
Offenbach, Germany Michael Rauschman
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