京都大学 / 新制・課程博士 / 博士(医学) / 甲第24829号 / 医博第4997号 / 新制||医||1067(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 森信, 暁雄, 教授 竹内, 理, 教授 濵﨑, 洋子 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Osteoarthritis (OA) is a debilitating joint disease that leads to significant pain, loss of mobility and quality of life. Knee malalignment results in increased joint pressure, which is a primary cause for OA progression. High Tibial Osteotomy (HTO) is a surgical procedure to correct malalignment and redistribute load in the knee joint, reduce peak pressure and delay OA progression. However, clinical outcomes have been unpredictable. Therefore, the aim of this study was to determine the relationship between malalignment and knee contact mechanics. A 3D computational model was created from magnetic resonance images of a cadaveric knee joint. A ligament tuning process was conducted to determine material properties. Finite element analyses were conducted, simulating end of weight acceptance during walking. Different wedge geometries were virtually removed to simulate malalignments from 14° valgus to 16° varus. Contact mechanics were sensitive to soft tissue material properties. In-vitro experiments were compared with computational modelling of the same specimen. Percent full-scale errors for contact force and pressure were less than 8%, demonstrating a unique subject-specific model validation. The native alignment of the cadaveric knee (1° varus) had medial and lateral compartment peak pressures of 4.28 MPa and 2.42 MPa, respectively. The medial:lateral force ratio was 70%:30%. Minimum contact stress did not occur at a Mechanical Axis Deviation (MAD) of zero millimetres nor at the Fujisawa Point, which are common targets for HTO correction. Results showed very strong correlations (r >0.94) between MAD and joint contact loading. This study is the first to demonstrate the relationship between stress (normal, shear, contact pressure) and MAD in a subject-specific model. This is a prerequisite for the development of a tool that could help surgeons make informed decisions on the degree of realignment required to minimise peak joint loading, thereby delaying OA progression.

Submitted by Ana Lúcia Torres (bfmhuap@gmail.com) on 2017-10-04T13:09:23Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese Ricardo Bastos.pdf: 1699294 bytes, checksum: 9f66927af352d688894773afaee06cdd (MD5) / Approved for entry into archive by Ana Lúcia Torres (bfmhuap@gmail.com) on 2017-10-04T13:09:37Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese Ricardo Bastos.pdf: 1699294 bytes, checksum: 9f66927af352d688894773afaee06cdd (MD5) / Made available in DSpace on 2017-10-04T13:09:37Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese Ricardo Bastos.pdf: 1699294 bytes, checksum: 9f66927af352d688894773afaee06cdd (MD5) Previous issue date: 2013 / Universidade Federal Fluminense / Osteotomia tibial alta (OTA) é um recurso frequentemente utilizado para o tratamento da artrose de joelho em pacientes jovens com o objetivo de retardar a necessidade de uma artroplastia total de joelho (ATJ). O objetivo do estudo foi de avaliar a influência da técnica de OTA (adição ou subtração) no resultado final da ATJ e comparar a sobrevida das cirurgias de osteotomias com a idade dos pacientes no momento do procedimento Nossa hipótese é que o alinhamento do membro, seguimento clínico dos pacientes e taxa de complicações sejam iguais em pacientes submetidos a ATJ após OTA de adição e subtração além de que as osteotomias de subtração apresentem uma maior duração até a ne-cessidade de realização da ATJ. Supomos também que a idade dos pacientes na época das osteotomias tenha uma relação linear positiva com a sobrevida desta cirurgia. Cento e quarenta e uma ATJs com antecedente de cirurgia de OTA (24 osteotomias de adição e 117 de subtração) foram selecionadas. Fatores intra-operatórios, resultados clínicos e alinhamento do membro foram analisados. A duração (sobrevida) das 2 diferentes técnicas de osteotomia até a realização da ATJ, assim como o impacto da idade dos pacientes na duração das duas técnicas desta cirurgia, também foram observados. Não foram observadas diferenças significativas nos escores IKS quando comparadas as duas técnicas cirúrgicas. Foi observada uma tendência a maior necessidade de uma osteo-tomia da tuberosidade anterior da tíbia (TAT) no grupo das osteotomias de subtração. Foi encontrada uma maior necessidade de liberação de partes moles (release) medial mais extensa no grupo das osteotomias de adição e uma liberação de partes moles lateral mais importante no grupo das osteotomias de subtração. Não foram encontradas diferenças no tempo de is-quemia, taxas de complicação ou no eixo mecânico final do membro inferior entre os dois grupos. O alinhamento radiográfico, resultados funcionais, objetivos e taxas de complicações são iguais em pacientes que se submetem a uma ATJ após a realização de uma OTA de adição e de subtração. A cirurgia de osteotomia tibial alta de subtração parece apresentar uma longe-vidade (sobrevida) maior até a necessidade da realização de uma artroplastia total de joelho quando comparada a uma osteotomia tibial de adição. Existe uma relação positiva e significa-tiva entre a idade do paciente na época da realização da osteotomia e a duração dessa cirurgia até a necessidade de uma artroplastia / High tibial osteotomy (HTO) is frequently used to treat varus osteoarthritis in younger patients with the goal of delaying the need for total knee arthroplasty (TKA). While it has been reported that the results of TKA following HTO are worse than those in patients without prior knee surgery, the influence of osteotomy technique (medial opening-wedge versus lat-eral closing-wedge) has not been explored. The purpose of this study was to evaluate the in-fluence of HTO technique on the performance and results of TKA. Our hypothesis is that the limb alignment, clinical follow-up and rate of complications are equal in patients undergoing TKA after closing-wedge and opening-wedge osteotomies and that the closing-wedge osteotomies have a higher survival rate when compared to open-ing- wedge osteotomies. We also suppose that younger patients at the time of the osteotomies have a longer delay until the need of performing a TKA. A hundred and one TKA’s performed in 118 patients with prior HTO (24 opening wedge and 117 closing wedge) were reviewed at a mean follow-up of 2 years. Reviewed data included intra-operative factors (tourniquet time, the need for additional exposure, and intra-operative complications), clinical results (International Knee Score (IKS)), and radiographic assessment of limb alignment. There was no significant difference in IKS scores based on osteotomy technique. There was a trend toward an increased need for tibial tubercle osteotomy in the closing-wedge group. There was an increased need for extensive medial release in the opening-wedge group and extensive lateral release in the closing-wedge group. No differences in tourniquet time, complication rates, or hip-knee-ankle angle were noted between the two groups. Radiographic limb alignment, patient-reported outcomes, and complication rates are equal in patients undergoing TKA after opening and closing wedge HTO. Closing-wedge high tibial osteotomy has a longer survival until the necessity of a total knee arthroplasty when compared to an opening-wedge high tibial osteotomy. There is a posi-tive and significant relationship between the patient's age at the time of the osteotomy and the survival of this surgery

L’Ostéotomie Tibiale de Valgisation (OTV) par ouverture médiale est un traitement conservatif efficace dans le traitement de la gonarthrose médiale chez le patient jeune et actif présentant un défaut d’alignement du membre inférieur. Ce défaut entraine un déséquilibre dans la répartition des charges transitant dans le genou et est un facteur de risque la gonarthrose. L’objectif est de corriger l’alignement en corrigeant une déformation osseuse du tibia proximal. Une coupe osseuse médiolatérale incomplète partant du bord médial de la métaphyse tibiale et orientée vers l’articulation tibio-fibulaire permet de créer une ouverture sur le bord médial par rotation autour de la charnière latérale, épaisseur d’os non-coupée sur le bord latéral. L’importance de l’ouverture dépend de la déformation osseuse et du stade d’arthrose. La réussite de l’OTV par ouverture médiale est conditionnée par une correction précise, un montage d’ostéosynthèse stable et une charnière latérale préservée pendant l’ouverture. L’objectif de cette thèse était de proposer une méthodologie de planification préopératoire à associer à une instrumentation patient-spécifique réalisée en impression 3D. Cette instrumentation devait permettre d’appliquer la correction souhaitée dans les plans frontal et sagittal mais aussi de préserver la charnière latérale pendant la chirurgie. Nos résultats ont montré, grâce aux études in-vitro et in-vivo réalisées au cours de la thèse, que le guide de coupe patient-spécifique développé permet de reproduire avec précision la planification préopératoire en apportant de la sécurité au geste opératoire tant au niveau de la précision que de la préservation de la charnière latérale. / Medial Opening Wedge High Tibial Osteotomy (MOWHTO) is an efficient conservative surgical treatment for young and active patients with moderate medial gonarthrosis and varus lower limb malalignment. Varus malalignment unbalances load distribution in the knee, which is a gonarthrosis risk factor. MOWHTO aims to correct the lower limb alignment by correcting the proximal tibia bony deformity. Incomplete mediolateral cut is performed in the proximal tibia from the medial side of the tibial metaphysis towards the tibiofibular joint, and then opened by rotation around the lateral hinge which is the remaining uncut bone thickness on the lateral side. Amount of the opening depends on the importance of the proximal tibial deformity and on the medial gonarthrosis stage. MOWHTO success remains on precise correction, stable osteosynthesis system and lateral hinge preservation during the opening. Objective of this thesis was to propose a preoperative planning methodology to be associated with 3D printed patientspecific instrumentation. This instrumentation was intended to apply the correction chosen by the surgeon in the frontal and sagittal planes, but also to preserve the lateral hinge during the surgery. Our in-vitro and in-vivo results have shown that the developed patient-specific cutting guide make it possible to accurately reproduce the preoperative planning with security to the surgical gesture by bringing accuracy and lateral hinge preservation.