[Truncated abstract] Articular cartilage (AC) covers the surface of synovial joints providing a nearly frictionless bearing surface and distributing mechanical load. Joint trauma can damage the articular surface causing pain, loss of mobility and deformation. Currently there is no uniform treatment protocol for managing focal cartilage defects, with most treatment options targeted towards symptomatic relief but not limiting the progression into osteoarthritis (OA). Autologous chondrocyte implantation (ACI) and more recently matrix-induced autologous chondrocyte implantation (MACI), have emerged as promising methods for producing hyaline or hyaline-like repair tissue, however there remains some controversy regarding the exact histological nature of the tissue formed. Histological characterisation of AC repairs requires destructive tissue biopsy potentially inducing further joint pathology thereby negating the treatment effect. OA is recognised as a major cause of pain, loss of function and disability in Western populations, however the exact aetiology is yet to be elucidated. The assessment of both OA and cartilage repair has been limited to macroscopic observation, radiography, magnetic resonance imaging (MRI) or destructive biopsy. The development of non-destructive AC assessment modalities will facilitate further development of AC repair techniques and enable early monitoring of OA changes in both experimental animal models and clinical subjects. Confocal laser scanning microscopy (CLSM) is a type of fluorescence microscopy that generates high-resolution three-dimensional images from relatively thick sections of tissue. ... Biomechanical analysis suggested that the mechanical properties of MACI tissue remain inferior for at least three months. This study showed the potential of a multi-site sheep model of articular cartilage defect repair and validated its assessment via LSCA. Finally, the LSCA was used to arthroscopically image the cartilage of an intact fresh frozen cadaveric knee from a patient with clinically diagnosed OA. Images were correlated to ICRS (Outerbridge) Grades I-IV and histology. The LSCA gave excellent visualization of cell morphology and cell density to a depth of up to 200'm. Classical OA changes including clustering chondrocytes, surface fibrillation and fissure formation were imaged. Fair to moderate agreement was demonstrated with statistically significant correlations between all modalities. This study confirmed the viability of the LSCA for non-destructive imaging of the microstructure of the OA cartilage. In conclusion, the LSCA identified histological features of orthopaedic tissues, accurately quantified chondrocyte morphology and demonstrated classical OA changes. While the development and investigation of an ovine model of cartilage repair showed the treatment benefit of MACI, some biomechanical issues remain. Ultimately, the LSCA has been demonstrated as a reliable nondestructive imaging modality capable of providing optical histology without the need for mechanical biopsy. Medical Subject Headings (MESH): articular cartilage; autologous chondrocyte implantation; matrix-induced autologous chondrocyte implantation; biomechanics; cartilage; confocal microscopy; diagnosis; histology; image analysis; immunohistochemistry; magnetic resonance imaging; microscopy; osteoarthritis

Akute Sprengungen des Acromioclaviculargelenks sind eine häufige Verletzungsentität des jungen Erwachsenen. Für höhergradige Verletzungen wird eine operative Versorgung empfohlen, hierbei gibt es eine überwältigende Vielzahl an therapeutischen Möglichkeiten. Durch die wachsende Beliebtheit minimalinvasiver Behandlungsmöglichkeiten etablierten sich in den letzten Jahren arthroskopische Techniken zunehmend in der operativen Versorgung von ACG-Verletzungen. Die arthroskopischen Therapieempfehlungen unterlagen aufgrund einer häufig beobachteten Instabilität in der Horizontalebene des Acromioclaviculargelenks in den letzten Jahren einem Paradigmenwechsel. Für akute Acromioclaviculargelenkssprengungen empfiehlt die Mehrzahl der aktuellen Publikationen eine arthroskopische Versorgung mittels einer doppelten Implantation künstlicher Bandstrukturen zur Rekonstruktion der coracoclaviculären Ligamente in anatomischer Positionierung sowie eine zusätzliche operative Reparatur der acromioclaviculären Kapsel. Ein Konsens zu optimalen Versorgung höhergradiger Verletzungen besteht aktuell nicht. Ziel der vorliegenden Arbeit war es, die aktuellen Empfehlungen auf Grundlage der biomechanischen Eigenschaften des Acromioclaviculargelenks in der Horizontalebene nach arthroskopischer Rekonstruktion zu reevaluieren. Dafür sollte überprüfen werden, inwieweit die Positionierung und Anordnung der Rekonstruktionsimplantate der coracoclaviculären Ligamente sowie eine zusätzliche Stabilisierung der Acromioclavicularkapsel mittels Fadencerclage einen Einfluss auf die Stabilität im AC-Gelenk haben. Als Untersuchungsgegenstand dienten folgende Rekonstruktionsarten: • Single-Coracoclavicular-Tunnel (SCT) Technik als Rekonstruktion mittels eines coracoclaviculär eingebrachten TightRope™-Implantates (Arthrex Inc.; Naples, FL, USA) mit zusätzlicher acromioclaviculärer Fadencerclage • Double-Coracovlavicular-Tunnel (DCT) Technik als Rekonstruktion mittels zweier coracoclaviculär eingebrachter TightRope™-Implantate (Arthrex, USA) in anatomischer Positionierung ohne additive Stabilisierung • Double-Coracovlavicular-Tunnel (DCT) Technik als Rekonstruktion mittels zweier coracoclaviculär eingebrachter TightRope™-Implantate (Arthrex, USA) in anatomischer Positionierung mit zusätzlicher acromioclaviculärer Fadencerclage • Double-Coracovlavicular-Tunnel (DCT) Technik als Rekonstruktion mittels zweier coracoclaviculär eingebrachter TightRope™-Implantate (Arthrex, USA) in nicht-anatomischer (spiegelbildlicher) Positionierung mit zusätzlicher acromioclaviculärer Fadencerclage Die biomechanische Untersuchung erfolgte an Ethanol-Glycerin-fixierten menschlichen Schulterpräparaten. Die Auswertung erfolgte mit einem optischen 3D-Messsystem. In dieser Arbeit konnte nachgewiesen werden, dass eine Rekonstruktion der coracoclaviculären Bänder mit zwei eingebrachten TightRope™-Implantaten (Arthrex, USA) in anatomischer Positionierung mit und ohne zusätzliche acromioclaviculäre Cerclage in einer signifikant höheren Stabilität in der Horizontalebene des Acromioclaviculargelenks resultiert als eine Rekonstruktion mit nur einem TightRope™-Implantat (Arthrex, USA), auch mit zusätzlicher acromioclaviculärer Cerclage. Zwischen den Rekonstruktionstechniken der coracoclaviculären Bänder mit zwei Implantaten gab es keinen signifikanten Unterschied in der Stabilität durch eine zusätzliche acromioclaviculäre Cerclage. Die Rekonstruktion der coracoclaviculären Ligamente mit zwei eingebrachten TightRope™-Implantaten (Arthrex, USA) in anatomischer Positionierung resultierte in einer signifikant höheren Stabilität in der Horizontalebene als bei spiegelbildlicher Positionierung der eingebrachten Implantate. Im Gegensatz zu dem aktuell populären Ansatz, eine hinreichende Stabilisierung in der Horizontalebene des Acromioclaviculargelenks durch eine arthroskopische Rekonstruktion mittel künstlicher Ligament-Implantate sei nur mit einer zusätzlichen Rekonstruktion der acromioclaviculären Kapsel zu erreichen, konnte in dieser Arbeit demonstriert werden, dass eine Rekonstruktion der AC-Kapsel nicht generell die Stabilität in der Horizontalebene im AC-Gelenk beeinflusst. Die Stabilisierung hängt maßgeblich von einer suffizienten Rekonstruktion der coracoclaviculären Ligamente in anatomischer Positionierung ab.

O autor estudou as propriedades biomecânicas dos tendões dos músculos tibial anterior e tibial posterior congelados a -20°C e a -86°C extraídos de cadáveres humanos frescos. Foram realizados ensaios mecânicos de tração até a ruptura e determinadas as seguintes propriedades: resistência máxima, coeficiente de rigidez, módulo de elasticidade e alongamento máximo relativo. Os dados obtidos foram comparados aos existentes na literatura relativos ao ligamento cruzado anterior, ligamento da patela e aos tendões dos músculos grácil e semitendíneo / The author studied the mechanical properties of the anterior and posterior tibialis muscle tendons frozen at -20°C and -86°C obtained from fresh-frozen human cadavers. The tendons were submitted to axial traction until failure and the following properties were determined: ultimate load, stiffness, modulus of elasticity and relative strain. Data obtained were compared to those from the literature related to the anterior cruciate ligament, patellar tendon, gracilis and semitendinous tendons

O autor estudou as propriedades biomecânicas dos tendões dos músculos tibial anterior e tibial posterior congelados a -20°C e a -86°C extraídos de cadáveres humanos frescos. Foram realizados ensaios mecânicos de tração até a ruptura e determinadas as seguintes propriedades: resistência máxima, coeficiente de rigidez, módulo de elasticidade e alongamento máximo relativo. Os dados obtidos foram comparados aos existentes na literatura relativos ao ligamento cruzado anterior, ligamento da patela e aos tendões dos músculos grácil e semitendíneo / The author studied the mechanical properties of the anterior and posterior tibialis muscle tendons frozen at -20°C and -86°C obtained from fresh-frozen human cadavers. The tendons were submitted to axial traction until failure and the following properties were determined: ultimate load, stiffness, modulus of elasticity and relative strain. Data obtained were compared to those from the literature related to the anterior cruciate ligament, patellar tendon, gracilis and semitendinous tendons

Atualmente, os bons resultados na lesão do ligamento cruzado posterior por avulsão óssea na tíbia associam-se ao tratamento cirúrgico e precoce. A técnica convencional é a fixação com parafuso pela via de acesso posterior do joelho, com abordagem direta das estruturas vasculares e nervosas da região. Neste estudo experimental em 20 joelhos de cadáveres, buscamos apresentar uma alternativa com amarrilho por via artroscópica, comparando-o com a técnica convencional, através da inspeção direta e de testes biomecânicos. Houve falha na fixação de apenas um exemplar de cada método e medidas de deslocamento tibial posterior (p=0,23) e rigidez média (p=0,28) sem diferenças significativas entre as duas técnicas. Concluímos ser o amarrilho artroscópico viável e uma alternativa no tratamento desta lesão. / Nowadays, good results on the management of posterior cruciate ligament bony avulsion of the tibia are associated with early surgical repair. The usual method of treatment is the open posterior approach with screw fixation, wich requires popliteal neurovascular bundle direct manipulation. This study presents a new arthroscopic suture and compares it with the conventional technique, using biomechanical tests and direct inspection in cadaveric specimens (20 knees). On both methods there was a fixation fail in one knee. The analisys of tibial posterior displacement (p=0,23) and stiffness (p=0,20) were similar for the two methods. The Arthroscopic suture presented is an effective reattachment method for this fracture pattern.

Atualmente, os bons resultados na lesão do ligamento cruzado posterior por avulsão óssea na tíbia associam-se ao tratamento cirúrgico e precoce. A técnica convencional é a fixação com parafuso pela via de acesso posterior do joelho, com abordagem direta das estruturas vasculares e nervosas da região. Neste estudo experimental em 20 joelhos de cadáveres, buscamos apresentar uma alternativa com amarrilho por via artroscópica, comparando-o com a técnica convencional, através da inspeção direta e de testes biomecânicos. Houve falha na fixação de apenas um exemplar de cada método e medidas de deslocamento tibial posterior (p=0,23) e rigidez média (p=0,28) sem diferenças significativas entre as duas técnicas. Concluímos ser o amarrilho artroscópico viável e uma alternativa no tratamento desta lesão. / Nowadays, good results on the management of posterior cruciate ligament bony avulsion of the tibia are associated with early surgical repair. The usual method of treatment is the open posterior approach with screw fixation, wich requires popliteal neurovascular bundle direct manipulation. This study presents a new arthroscopic suture and compares it with the conventional technique, using biomechanical tests and direct inspection in cadaveric specimens (20 knees). On both methods there was a fixation fail in one knee. The analisys of tibial posterior displacement (p=0,23) and stiffness (p=0,20) were similar for the two methods. The Arthroscopic suture presented is an effective reattachment method for this fracture pattern.