Zusammenfassung Markus Zeißler Gelenkknorpeldicke und Spaltlinienverlauf im Hinblick auf eine autologe osteochondrale Transplantation vom Knie ins Ellbogengelenk beim Hund Klinik für Kleintiere der Veterinärmedizinischen Fakultät der Universität Leipzig ( 87 Seiten, 19 Abbildungen, 221 Literaturangaben) Eingereicht im August 2012 Schlüsselwörter: autologe osteochondrale Transplantation – Ellbogengelenk-Kniegelenk – Hund – Knorpeldicke – Spaltlinien – Mosaikplastik Zielstellung: Ziel der Arbeit war es eine autologe osteochondrale Transplantation zur Therapie einer Osteochondrosis dissecans (OCD) beim Hund unter Berücksichtigung der morphologischen Grundlagen an potentiellen Empfängerstellen des Ellbogengelenkes und Spenderstellen des Kniegelenkes, durchzuführen. Dazu wurden die Knorpeldicke bestimmt und die Spaltlinien des Knorpels dargestellt und die potentiellen Empfänger- und Spenderstellen miteinander verglichen. Material und Methode: Es wurde eine postmortale Studie an Gelenken von 20 über 20 kg schweren knorpelgesunden Hunden durchgeführt. An 15 Vorder- und den entsprechenden 15 Hintergliedmaßenpaaren wurden mit einem 2,7 mm Hohlmeißel osteochondrale Zylinder an jeweils vier Empfängerstellen an der Trochlea humeri und 14 potentiellen Spenderstellen im Kniegelenk entnommen und mittels eines hochauflösenden digitalen Röntgensystems die Knorpeldicke bestimmt. Nachträglich wurde an fünf zusätzlichen Hintergliedmaßen, die die selben Kriterien wie die anderen 15 Gliedmaßen erfüllten, kurz vor Abschluss der Studie ein bis dahin nicht bekanntes Spenderareal (CO) mit jeweils drei Spenderstellen nachbeprobt und ebenfalls die Knorpeldicke vermessen. Weiterhin wurden an den ipsilateralen 15 Gliedmaßen die Spaltlinien der Trochlea humeri und des gesamten distalen Femurs präpariert, um die Hauptausrichtung der Kollagenfasern darzustellen, die ein Ausdruck der Dehnungsausrichtung und damit der Belastung des hyalinen Knorpels sind. Dazu wurde eine in königsblauer Tinte benetzte Präpariernadel alle drei Millimeter senkrecht in den Gelenkknorpel eingestochen und damit entstandene Spaltlinien dargestellt. Dies gelang erfolgreich an zehn Vorder- und Hintergliedmaßen. Ergebnisse: Es konnte ein primär transversal verlaufendes Spaltlinienmuster im Kniegelenk für die innerhalb der Trochlea gelegenen Spenderstellen nachgewiesen werden. Die Spenderareale außerhalb des Femoropatellargelenkes wiesen keine Spaltlinien auf. Die Trochlea humeri wies ein konstantes zentripetales Spaltlinienmuster auf. An der typischen Prädilektionsstelle der Osteochondrosis dissecans in der Trochlea humeri wurde eine Knorpeldicke im Median von 0,55 mm (95%KI: 0,48-0,6) bestimmt. Innerhalb der Trochlea ossis femoris wurde eine mediane Knorpeldicke an den inneren lateralen Spenderstellen von 0,45 mm (95% KI: 0,42-0,48), an den inneren medialen Spenderstellen von 0,49 mm (95% KI: 0,49-0,63) und an den lateral und medialen Spenderstellen der distalen Trochlea von 0,56 mm (95%KI: 0,49-0,63) gemessen. Die niedrigsten Knorpeldicken wiesen die äußeren Spenderstellen der Trochlea ossis femoris auf mit Median 0,2 mm (95% KI: 0,16-0,23) an den lateralen und 0,24 mm (95% KI: 0,17-0,31) an den medialen äußeren Spenderstellen. Schlussfolgerungen: Spenderstellen außerhalb des Femoropatellargelenkes weisen deutlich zu niedrige Knorpeldicken und ein fehlendes Spaltlinienmuster auf und sollten deshalb unter Berücksichtigung der morphologischen Situation zur OAT beim Hund am Ellbogen vermieden werden. Die Spenderstellen an der distalen Trochlea ossis femoris eigenen sich am besten zur Transplantation in die Trochlea humeri. Mit diesen Daten wird es erstmals möglich sein die osteochondrale Transplantation vom Kniegelenk ins Ellbogengelenk beim Hund zur Therapie einer OCD unter Berücksichtigung der morphologischen Grundlagen Knorpeldicke und Spaltlinienmuster durchzuführen. Inwieweit eine Verbesserung vor allem der Langzeitprognose beim Hund unter Berücksichtigung dieser Aspekte erreicht wird, muss in weiteren klinischen Studien untersucht werden. Allerdings müssen weitere wichtige Kriterien wie Oberflächengeometrie und Spenderstellenmorbidität zusätzlich beachtet werden. / Summary Markus Zeißler Cartilage thickness and split-line as a basic principal for an autologous osteochondral transplantion from stifle to the elbow joint in dogs Department of Small Animal Medicine, Faculty of Veterinary Medicine, University of Leipzig Submitted in August 2012 (87 pages, 19 figures, 221 references) Keywords: autologous osteochondral transplantation – elbow joint – stifle joint – dog– cartilage thickness – split- line pattern – mosaicplasty Aim of the study: was to conduct an osteochondral transplantation as a treatment for Osteochondritis dissecans in dogs under consideration of the morphological basics to provide potential recipient sites on the elbow and donor sites in the stifle joint. In order to compare the potential donor and recipient sites the cartilage thickness was measured and the splitt line patterns were depicted. Material and methods: A postmortal study was conducted on joints with healthy cartilage of 20 dogs with a bodyweight over 20 kg. From 15 forelimb- and hindlimb pairs, osteochondral plugs were collected with a 2.7mm hollow chisel .These were taken from 4 donor sites on the trochlea humeri and 14 recipient sites from the stifle,respectively, and the cartilage thickness was measured with a high-solving digital xray system. Shortly before the end of this study a donor area (CO), until then unknown, was sampled from 5 additional hindlimbs with the same criteria as before. On each donor region, 3 osteochondral grafts were taken and the cartilage thickness measured.Furthermore, split line patterns from the trochlea humeri and the stifle were depicted on 15 ipsilateral limbs. The split line patterns represent the main orientation of the collagen fibers and this is an expression of the strain orientation and thus show us the load of the cartilage. A needle dipped in India ink was pierced perpendicular to the cartilage surface in a 3mm interval to produce split line patterns.This succeeded in 10 fore- and hindlimbs. Results: The donor sites in the trochlea of the stifle have a primary transversal splitline orientation.The donor sites outside the trochlea of the stifle show no split line patterns. The trochlea humeri display a constant zentripetal split line orientation. In the Trochlea humeri the mean cartilage thickness was 0.55mm (95% CI: 0.42-0.61). The mean cartilage thickness within the femoral trochlea on the inner lateral donor sites measured 0.45mm (95%CI:0.42-0.48), on the inner medial donor sites was 0.49mm( 95%CI:0.49-0.63),and on the medial and lateral donor sites of the distal femoral trochlea were 0.56mm(95%CI:0.49-0.63), respectively. The thinnest cartilage reported in the donor sites outside the femoral trochlea measured laterally 0.2mm (95% CI: 0.16-0.23) and medially 0.24mm (95% CI: 0.17-0.31). Conclusions: Donor sites outside the femoropatellar joint have too thin cartilage thickness and no split line orientation. Due to these morphological conditions they should be avoided for osteochondral autograft transplantation as donor sites for the trochlea humeri in dogs. The distal femoral trochlea is the best location for autologous grafting of the trochlea humeri. It is now possible to carry out an autologous osteochondral transplantation from stifle to the elbow joint for the treatment of Osteochondritis dissecans in dogs in consideration of morphological basic principals of cartilage thickness and split- line patterns. Further clinical evaluation is needed in order to assess the value of these findings for the long term prognosis. However, additional other important criteria, such surface curvature and donor site morbidity, must be considered.

L’objectif de cette étude est de vérifier si un ciment ostéoconducteur résorbable utilisé comme technique de fixation de greffons ostéochondraux permet d'obtenir une stabilité initiale supérieure à celle obtenue avec la technique de mosaicplastie originalement décrite. Il s’agit d’une étude biomécanique effectuée sur des paires de fémurs cadavériques bovins. Pour chaque paire de fémurs, des greffons ostéochondraux autologues ont été insérés et stabilisés au moyen d’un ciment biorésorbable (Kryptonite, DRG inc.) sur un fémur alors qu’au fémur controlatéral, les greffons ont été implantés par impaction selon la technique usuelle de mosaicplastie. Des greffons uniques ainsi que des greffons en configuration groupée ont été implantés et soumis à une évaluation biomécanique. Les charges axiales nécessaires pour enfoncer les greffons de 1, 2 et 3 mm ont été comparées en fonction de la technique de stabilisation utilisée, ciment ou impaction, pour chaque configuration de greffons. Les résultats démontrent que les greffons ostéochondraux cimentés uniques et groupés ont une stabilité initiale supérieure à celle de greffons non cimentés sur des spécimens cadavériques bovins. L’obtention d’une plus grande stabilité initiale par cimentation des greffons ostéochondraux pourrait permettre une mise en charge précoce post-mosaicplastie et mener à une réhabilitation plus rapide. / The objective of this project is to compare the primary stability of osteochondral autografts stabilized with a resorbable osteoconductive bone cement to that of bottomed press fit grafts inserted according to the original mosaicplasty technique. Biomechanical testing was conducted on pairs of cadaveric bovine femurs. For each femoral pair, osteochondral grafts were inserted and stabilized with an osteoconductive bone cement (Kryptonite, DRG inc.) on one bone whereas on the controlateral femur, grafts were inserted in a press fit fashion. Grafts were inserted in 2 different configurations, single grafts as well as groups of 3 adjacent grafts, and submitted to biomechanical testing. Axial loads needed to sink the grafts to 1, 2 and 3 millimeters below cartilage level were recorded and compared according to the fixation technique, cement or press-fit impaction, for each graft configuration. According to those results, cemented osteochondral autografts appear more stable than press fit grafts for both single and 3-in-a-row configurations. Using such a cementation technique could potentially prevent the initial loss of stability that has been shown to occur with osteochondral grafts in the post-operative period, allowing patients to perform early weight bearing and rehabilitation.

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

Osteoarthritis is one of the most common causes of disability in adults in America. It is a progressive and degenerative disease where the articular cartilage is broken down and lost from the surfaces of bones causing chronic pain and swelling in the joints, and currently has no cure. The most commonly osteoarthritis starts from a focal lesion on the cartilage surface, which will expand on the surface and downwards through the thickness of the tissue. The current gold standard for correcting cartilage focal lesions is the osteochondral autograft/allograft transplantation (OAT), which replaces the defect with a fresh osteochondral graft. The main limiting factor for using the OAT comes from the limited number of autograft and allografts that are available for implantation. To address the concern of graft availability, this study will look at the development of a porcine osteochondral xenograft (OCXG). The first aim of this research is to establish a decellularization protocol that will remove the antigens and cellular debris, which are the leading causes of graft rejection when implanting animal tissue in humans. The second aim of this study is restoring the mechanical strength of the OCXG that was lost during the decellularization process through crosslinking the tissue using genipin and epigallocatechin gallate (EGCG). The third aim is comparing the performance of the complete crosslinked OCXG at different degrees of crosslinking in a long-term goat animal model. The final aim is an alternative way to correct focal lesions through the development of an injectable collagen stabilizing treatment with genipin and punicalagin that will slow or stop the growth of a lesion and prevent osteoarthritis.

Im Rahmen der Biomechanik werden der Einfluss mechanischer Bedingungen auf die Heilung biologische Gewebe, wie zum Beispiel Knochen und Knorpeln untersucht. Die vorliegende Arbeit bestimmte zum Einen am Beispiel des Humerus das mechanische Verhalten von intakten und frakturierten Knochen mit verschiedener Knochenqualität (Osteoporose versus gesunden Knochen) unter verschiedenen physiologischen Belastungen. Dazu wurde ein Finite Elemente Modell des entsprechenden Knochens erstellt. Die Knochenqualität erwies sich für die Heilung als wichtigerer Parameter, als die jeweilige physiologische Belastung. Künftige Therapien der Osteoporose sollten daher die jeweils individuelle Dichteverteilung des entsprechenden Knochens explizit berücksichtigen. Zum zweiten wurde ein biphasisches, linear-elastisches Gewebedifferenzierungsmodell entwickelt, mit dem durch iterative Berechnung der Elastizität die Heilung eines osteochondralen Defektes verfolgt werden konnte. Damit konnten die Steifigkeiten und die Orte im und um den ursprünglichen Defekt, an denen sich während der osteochondralen Heilung die verschiedenen Gewebearten neu bilden, quantitativ und qualitativ (Vergleich mit Tierexperimentation) ermittelt werden. Der Erfolg dieses Modells erlaubte die Antwort auf verschiedene Fragestellungen: Einfluß der Defekt- und Gelenkgeometrie auf die Häufigkeit des Auftretens osteochondraler Defekte und ihre Heilungschancen, sowie die Wahl der Steifigkeit eines optimalen Biomaterials zur Defektausfüllung. Osteochondrale Defekte scheinen in konkaver Geometrie etwas besser zu heilen, weil dort mehr hyaliner Knorpel gebildet wird. Grafts mit derselben Steifigkeit des ursprünglichen Knochens bilden kalzifizierenden Knorpel um mehr hyaliner Knorpel am Ende des Heilungsprozesses und sind daher weicheren Biomaterialien vorzuziehen. / In biomecanics the influence of mechanical conditions on healing of biological tissues as bones or soft tissues are analysed. In the frame of this work the mechanical behavior of intact and fractured bones with different bone qualities (osteoporotic versus normal) has been examined in a proximal humerus. Therefore a finite element model of the bone was constructed. It was found that the bone quality has a stronger impact on healing than the actual physiological loading condition does. Hence, for a future therapy of osteoporosis the precise density distribution of each individual bone must be considered. In a second step a biphasic, linear-elastic model for tissue differentiation was developed, where osteochondral healing was simulated by iterative calculation of the elastic modulus of Young within the joint region. By using this model it was possible to predict in which order in all regions of the joint the osteochondral healing took place. The stiffnesses of the newly differentiated tissues agreed well to the derived quantities of animal experimentation. Hence, this tissue differentiation model could be used to analyse some questions concerning the geometry and healing success of osteochondral defects. In concave geometry more hyaline cartilage was formed, which has better mechanical properties than fibrous one. Moreover, the stiffness of an optimal biomaterial could be determined: grafts with the same stiffness as the original bone will lead to the formation of calcified bone and more hyaline cartilage, which is favourable compared to a less stiffer biomaterial.

A cartilagem articular é um tema amplamente discutido na literatura por meio de vários estudos e pesquisas. Com o presente estudo, busca-se uma proposta inovadora e original no uso de um biomaterial composto e o desenvolvimento de uma cartilagem artificial que aja como coxim elástico, apresentando características de gel fibro-reforçado com finalidade biomimética mecânica que imite o comportamento da cartilagem articular. Foi conceituado um implante que tivesse uma superfície tribológica para contato com a cartilagem do platô tibial e gradualmente se convertesse em região osteo-integrável para fixação mecânica no osso subcondral. Foi desenvolvido um biomaterial composto por poliuretano e microfibra de biovidro 45S5 em gradiente funcional que foi obtido e validado através de ensaios in vitro, microscopia eletrônica de varredura e análise histológica. Nos testes in vitro seja na condição de citotoxicidade direta ou indireta, notou-se que a quantidade de células foi estatisticamente semelhante ao controle negativo, e estatisticamente diferente do controle positivo indicando que o biomaterial composto de poliuretano e microfibra de biovidro 45S5 apresentou não toxicidade direta ou indireta da amostra e ainda promoveram o crescimento e o espalhamento celular, resultados que o habilitaram para a continuidade nos estudos com experimentos in vivo com coelhos. O material foi manufaturado para aplicação em defeitos osteocondrais de coelhos medindo 3mm de diâmetro e 4mm de profundidade que foi realizado na região central da tróclea femoral. Após períodos experimentais de 15, 30 e 90 dias as análises de microscopia eletrônica de varredura mostrou na região distal da superfície tribológica uma neo-formação de uma estrutura semelhante as trabéculas ósseas que foi considerada biomimética confirmadas por análises histológicas, e na região proximal à superfície tribológica a presença de tecido fibrocartilaginoso com condrócitos e ricamente vascularizado, validando com sucesso o conceito proposto para o implante. / Articular cartilage has been widely discussed in the literature by means of several studies and researches. The present thesis reports on an innovative and original proposal to use a biomaterial compound and the development of an artificial cartilage that acts as a cushion rubber with characteristics of fiber-reinforced gel with biomimetic mechanical purpose mimicking the behavior of articular cartilage. An implant with a tribological surface for contact with the cartilage of the tibial plateau was designed. It should gradually turn into an osteo-integrable region for mechanical fixation in the subchondral bone. A biomaterial composed of polyurethane and bioglass microfiber in functional gradient was then developed and validated by scanning electron microscopy and histological analysis through in vitro tests. Under either direct or indirect cytotoxicity conditions, the tests showed that the amount of cells is statistically similar to negative control and statistically different from the positive control, indicating that the biomaterial composed of polyurethane and bioglass microfiber showed no direct or indirect toxicity and promoted cell growth and spreading. Such results allowed continuing the studies with in vivo experiments with rabbits. The material was manufactured for use in 3mm diameter and 4mm depth osteochondral defects in the central region of the femoral trochlea of rabbits. After experimental periods of 15, 30 and 90 days, the scanning electron microscopy analysis showed a neo-formation of a structure similar to trabecular bones on the tribological surface in the distal region. This neo-formation was considered biomimetic, confirmed by both histological analysis and the presence of richly vascularized fibrocartilaginous tissues with chondrocytes in the region proximal to the tribological surface.

No description available.

A cartilagem articular é um tema amplamente discutido na literatura por meio de vários estudos e pesquisas. Com o presente estudo, busca-se uma proposta inovadora e original no uso de um biomaterial composto e o desenvolvimento de uma cartilagem artificial que aja como coxim elástico, apresentando características de gel fibro-reforçado com finalidade biomimética mecânica que imite o comportamento da cartilagem articular. Foi conceituado um implante que tivesse uma superfície tribológica para contato com a cartilagem do platô tibial e gradualmente se convertesse em região osteo-integrável para fixação mecânica no osso subcondral. Foi desenvolvido um biomaterial composto por poliuretano e microfibra de biovidro 45S5 em gradiente funcional que foi obtido e validado através de ensaios in vitro, microscopia eletrônica de varredura e análise histológica. Nos testes in vitro seja na condição de citotoxicidade direta ou indireta, notou-se que a quantidade de células foi estatisticamente semelhante ao controle negativo, e estatisticamente diferente do controle positivo indicando que o biomaterial composto de poliuretano e microfibra de biovidro 45S5 apresentou não toxicidade direta ou indireta da amostra e ainda promoveram o crescimento e o espalhamento celular, resultados que o habilitaram para a continuidade nos estudos com experimentos in vivo com coelhos. O material foi manufaturado para aplicação em defeitos osteocondrais de coelhos medindo 3mm de diâmetro e 4mm de profundidade que foi realizado na região central da tróclea femoral. Após períodos experimentais de 15, 30 e 90 dias as análises de microscopia eletrônica de varredura mostrou na região distal da superfície tribológica uma neo-formação de uma estrutura semelhante as trabéculas ósseas que foi considerada biomimética confirmadas por análises histológicas, e na região proximal à superfície tribológica a presença de tecido fibrocartilaginoso com condrócitos e ricamente vascularizado, validando com sucesso o conceito proposto para o implante. / Articular cartilage has been widely discussed in the literature by means of several studies and researches. The present thesis reports on an innovative and original proposal to use a biomaterial compound and the development of an artificial cartilage that acts as a cushion rubber with characteristics of fiber-reinforced gel with biomimetic mechanical purpose mimicking the behavior of articular cartilage. An implant with a tribological surface for contact with the cartilage of the tibial plateau was designed. It should gradually turn into an osteo-integrable region for mechanical fixation in the subchondral bone. A biomaterial composed of polyurethane and bioglass microfiber in functional gradient was then developed and validated by scanning electron microscopy and histological analysis through in vitro tests. Under either direct or indirect cytotoxicity conditions, the tests showed that the amount of cells is statistically similar to negative control and statistically different from the positive control, indicating that the biomaterial composed of polyurethane and bioglass microfiber showed no direct or indirect toxicity and promoted cell growth and spreading. Such results allowed continuing the studies with in vivo experiments with rabbits. The material was manufactured for use in 3mm diameter and 4mm depth osteochondral defects in the central region of the femoral trochlea of rabbits. After experimental periods of 15, 30 and 90 days, the scanning electron microscopy analysis showed a neo-formation of a structure similar to trabecular bones on the tribological surface in the distal region. This neo-formation was considered biomimetic, confirmed by both histological analysis and the presence of richly vascularized fibrocartilaginous tissues with chondrocytes in the region proximal to the tribological surface.

Articular cartilage injuries occur frequently in the knee joint. Several methods have been implemented clinically, to treat osteochondral defects but none have been able to produce a long term, durable solution. Photopolymerizable cartilage tissue engineering approaches appear promising; however, fundamentally, forming a stable interface between the tissue engineered cartilage and native tissue, mainly subchondral bone and native cartilage, remains a major challenge. The overall objective of this research is to find a solution for the current problem of dislodgment of tissue engineered cartilage at the defect site for the treatment of degraded cartilage that has been caused due to knee injuries or because of mild to moderate level of osteoarthritis. For this, an in-vitro model was created to analyze the integration of tissue engineered cartilage with the bone, healthy and diseased cartilage over time. We investigated the utility of hydroxyapatite (HA) nanoparticles to promote controlled bone-growth across the bone-cartilage interface in an in vitro engineered tissue model system using bone marrow derived stem cells. We also investigated the application of HA nanoparticles to promote enhance integration between tissue engineered cartilage and native cartilage both in healthy and diseased states. Samples incorporated with HA demonstrated significantly higher interfacial shear strength (at the junction between engineered cartilage and engineered bone and also with diseased cartilage) compared to the constructs without HA (p < 0.05), after 28 days of culture. These findings indicate that the incorporation of HA nanoparticles permits more stable anchorage of the injectable hydrogel-based engineered cartilage construct via augmented integration between bone and cartilage.

L’utilisation de greffon costal en chirurgie reconstructrice est connue et utilisée depuis longtemps et notamment en chirurgie maxillo-faciale. La greffe de cartilage costal fait partie de l’arsenal thérapeutique pour le service de Traumatologie, Orthopédie, Chirurgie Plastique et Reconstructrice du CHU de Besançon. Proposée initialement dans le traitement chirurgical de la rhizarthrose, les opérateurs de ce service, se sont progressivement appropriés cette technique et l’on utilisée pour d’autres indications traumatiques ou dégénératives pour réaliser une restauration cartilagineuse. Ainsi depuis 15 ans, en dehors de son utilisation en routine pour la rhizarthrose, ce greffon a été proposé dans l’arthrose péri-scaphoïdienne ou radio-carpienne mais aussi pour quelques cas de reconstruction post-traumatiques d’articulations digitales, de cals vicieux de radius, dans la maladie de kienböck avancée ou lors d’une perte de substance ostéo-cartilagineuse d’une tête humérale. Dans un premier temps, ce travail rapporte les différentes indications thérapeutiques et résultats cliniques de cette technique originale qui ont fait l’objet de publications scientifiques et notamment dans l’arthrose radio-scaphoïdienne débutante et dans un cas de reconstruction de tête humérale.Cette technique chirurgicale impose pour le prélévement du greffon ostéo-chondral costal, l’abord du thorax au niveau de la 8e côte en général. Les complications pleuro-pulmonaires sont très rares. La technique de prélèvement est simple mais doit être « démystifiée ». Dans ce but, le deuxième temps de ce travail propose de donner les repères topographiques et anatomiques nécessaires au prélèvement de ce greffon. Une étude anatomique complétée par une étude en radio imagerie a permis de situer la 8e jonction ostéo chondrale costale entre les processus épineux de la 11e vertèbre thoracique et la première vertèbre lombaire mais le plus souvent au niveau du processus épineux de la 12e vertèbre thoracique et au 2/3 de l’hémi périmètre thoraco-abdominal en partant du sillon médian du dos, quel que soit la morphologie thoracique, l’âge et le sexe du patient. Cette 8e jonction est de plus toujours située sous un seul muscle, le muscle oblique externe et protégée par un épais périchondre qui la protège des pédicules de l’espace inter costal, du fascia endo thoracique et de la plèvre pariétale.En chirurgie du membre thoracique, les implants de pyrocarbone utilisés dans l’arthrose radio carpienne et la rhizarthrose, avec les mêmes principes que les greffes ostéo chondrales costales, ne semblent pas donner pour le moment de résultats satisfaisants. Les cultures de chondrocytes autologues ou de cellules stromales mésenchymateuses avec des produits déjà commercialisés posent le problème de leur matrice qui doit à la fois contenir les cellules greffées, des facteurs de croissance et se substituer à la perte de substance cartilagineuse le temps de l’intégration. Enfin, au vue des résultats intéressants apportés par cette technique de greffe ostéo chondrale costale en chirurgie orthopédique du membre thoracique, il est envisagé d’éventuelles greffes ostéo cartilagineuses pour restaurer des pertes de substances cartilagineuse au membre pelvien que ce soit en situation d’urgence ou pour des situations dégénératives comme l’ostéo chondrite disséquante de genou ou au niveau de la cheville. Des tests biomécaniques doivent être réalisés pour vérifier la capacité du greffon ostéo chondral costal à supporter une mise en charge sur une articulation portante. / The use of costal graft in reconstructive surgery is known and used for a long time in maxillo-facial surgery. It is the same practice for the service of traumatologic, orthopédic, plastic and reconstructive surgery of the university hospital of Besançon. Firstly proposed in the surgical treatment of trapezo-metacarpal osteoarthritis, the operators of this service gradually appropriated this technique and used it for other traumatic or degenerative indications to restore a cartilage defect. Thus, since 15 years, this surgical technique has been proposed in trapezo-metacarpal osteoarthritis, peri-scaphoid or radio-carpal osteoarthritis, for some cases of post-traumatic fingers joint reconstruction, for malunion of distal radius, for advanced Kienbock disease and defect of osteo-cartilaginous substance of a humeral head. In a first time, this work reports the different therapeutic indications and clinical results of this original technique which have been the subject of scientific publications, especially in radio-scaphoid osteoarthritis and in a case of humeral head reconstruction.To obtain the osteo-chondral costal graft, this technique needs the surgical approach of the thorax and generally of the 8e rib. Pleuro-pulmonary complications are very uncommun. This surgical technique is simple but must be "demystified". Therefore, the second phase of this work proposes giving topographical and anatomical landmark necessary to obtain this graft. An anatomical study supplemented by a radio imaging study helped to situate the 8e osteo-chondral rib junction between the epineus process of the 11e thoracic vertebra and the first lumbar vertebra but more often at the 12e thoracic vertebra. In the thoraco-abdominal hemi perimeter, this junction was locate at the 2/3 starting from the median furrow of the back, whatever the thoracic morphology, age and sex of the patient. This 8e junction is more always located under the obliquus externus abdominis muscle and coated by a thick perichondrium which protects it from the inter costal pedicle, from the endo thoracic fascia and the parietal pleura. In surgery of upper limb, the pyrocarbon implants, used actually in radio carpal osteoarthritis and trapezo metacarpal osteoarthritis, with the same principles as the osteo chondral costal graft, do not appear to give satisfactory results. Autologous transplantation of chondrocytes or mesenchymal stromal cells cultures have problem of their matrix which must contain the grafted cells, growth factors and have to substitute for the cartilaginous defect. Finally, due to this interesting results brought by this costal osteo chondral grafting technique in orthopaedic surgery of the upper limb, we considered eventual cartilaginous transplants to restore articular defect to the lower member following a injury or a degenerative lesion such as dissecans osteo chondritis of knee or ankle. Biomechanical tests should be realised to verify the ability of the costal osteo chondral graft to support a load on a bearing joint.