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Background and objectives: In the treatment of bone-related diseases, the biomechanical testing data of cadaveric bone plays a fundamental role in the design and application of orthopedic prosthesis and artificial bone materials, as well as the building of FEMs. Of these, the sample preparation is directly related to the accuracy of test results, including the removal of bone marrow, and the treatment of chemical solutions. In addition, it is also essential to evaluate the bone quality of bone specimens being tested prior to mechanical testing. Based on these issues, in this thesis, our studies aimed to systematically summarize the methods currently available for assessing bone quality in human bone tissue, as well as to investigate the efficiency of different chemical solvents on the removal of marrow from cancellous bone and their effects on the mechanical properties. Methods: In the first study (i), a systematic review of the literature was conducted using PubMed and Web of Science databases with the goal of finding all articles describing the methods of assessing bone quality in human bone specimens. The search terms were “bone quality [Title/Abstract]” AND “human bone specimens”. In the second study (ii), cylindrical cancellous bone samples (Ø8 × 2 mm) were obtained from fresh-frozen human cadaver femoral condyles and assigned to two groups, treated with chemical solvent soaking (solvent group) and ultrasonic cleaning (ultrasound group), respectively. Each group was divided into several subgroups based on different treatments. The differences in material density (Δρb), apparent density (Δρapp), and porosity (ΔP) before and after treatment were used as evaluation indications. In the third study (iii), cylindrical cancellous bone samples (Ø6 × 12 mm) were harvested from fresh-frozen human bones, including spinal vertebrae and femoral heads. All samples were divided into two groups, i.e., immersed in physiological saline (saline-immersed group) and treated with a combination of acetone and physiological saline (acetone and saline-treated group). Before and after treatment, all samples were subjected to non-destructive compression tests (0.45% strain), and finally destructive tests with a strain of 50%. Actual density (ρact), initial modulus (E0), maximum stress (σmax), energy absorption (W), and plateau stress (σp) were calculated as evaluation indicators. Results: Firstly, based on previous studies, our systematic review (i) found that advanced techniques are playing an increasingly important role based on their multiple advantages. Non- invasive imaging modalities and mechanical testing techniques, as well as the assessment of bone composition, need to complement each other to provide comprehensive and ideal information on the bone quality of human bone specimens. Secondly, our second study (ii) showed that a combination of 99% ethanol and detergent solution (v/ v = 1:20), as well as a mixture of 99% ethanol and acetone (v/v = 1:1), seem to be the optimal defatting methods for 2 mm thick cancellous bone slices because of their advantages of effectiveness, easy- availability, low-cost and relative-safety. Moreover, chemical soaking for 24h indicated better marrow removal than ultrasonic cleaning with 99% ethanol or acetone for 20 or 40min. Finally, for the larger samples, which were investigated in the third study (iii), according to the results, a combination of acetone and ultrasonic bath for 4h failed to completely remove bone marrow from cancellous bone samples (Ø6×12mm). In this study, it was also observed that short-term storage in physiological saline is an appropriate choice and has no effect on the E0 of cancellous bone. However, treatment of cancellous bone with acetone resulted in changes in mechanical properties that could not be reversed by subsequent immersion in physiological saline. Conclusions: The results of this work provide a reference for bone quality assessment, sample preservation, and mechanical testing of cancellous bone, which is important for obtaining accurate biomechanical data. It may serve as a basis for future clinical applications and in vitro model building.

Background: To ensure adequate function after orthopedic tumor reconstruction, it is important to reattach the remaining soft tissue to the implant. This study aimed at obtaining mechanical properties of textile muscle-implant and muscle-bone connections in a preliminary test. Methods: Two groups of soft-tissue attachment were mechanically tested and compared: Native bone-muscle samples obtained from human femora and muscles attached to a prosthetic implant by means of Trevira® attachment tubes. Additionally, muscle samples were tested with muscle fibers aligned parallel and perpendicular to the tension load. A uniaxial load was exerted upon all samples. Results: Failure loads of 26.7 ± 8.8 N were observed for the native bone-muscle group and of 18.1 ± 9.9 N for the Trevira® group. Elongations of 94.8 ± 36.2 % were observed for the native bone-muscle group and 79.3 ± 51.8 % for the Trevira® group. The location of failure was mainly observed in the central area of the muscle fibers. Muscle fibers with parallel fiber orientation (47.6 ± 11.5 N) yielded higher tensile strength than those with perpendicular fiber orientation (14.8 ± 4.1 N). Conclusions: Our experiments showed that higher forces were transmitted in the origin and insertion areas than in areas of flat soft tissue reconstruction using attachment tubes. The data indicate that the tested material allows reattaching muscles, but without reinforcing the insertion site. Therefore, attachment tubes with region-dependent and potentially anisotropic material behavior might be advantageous to optimize muscle-bone load transmission after surgery, which may allow lower complication rates and shorter physical recovery.

Made available in DSpace on 2016-06-02T19:22:59Z (GMT). No. of bitstreams: 1 5431.pdf: 1635270 bytes, checksum: 9bcecaf0b4b4b6c82982c33a5ee5ec91 (MD5) Previous issue date: 2013-06-21 / Financiadora de Estudos e Projetos / The purpose of this study was to investigate the influence of high-intensity resistance training on the activity of bone matrix metalloproteinases (MMPs), biometric, biomechanical, biophysical and biochemical properties of young and aged rats. We used 62 intact male rats, Rattus norvegicus albinos ("Wistar") randomly distributed into 4 groups: young sedentary (YS), young trained (YT), older sedentary (OS) and old trained (OT). The rats (YT and OT) performed resistance training, during 12 weeks, consisted of climbing a vertical ladder with weights fixed on their tails. The sessions were executed three times a week, every other day. The biomechanical, physical, biochemical and MMP-2 activity of bones analysis were performed, respectively, using a universal testing machine, Archimedes principle, commercial kit and zymography. In this study, the training promoted a reduction of body mass in YT animals, and reduced bone stiffness and pro MMP activity in the OT group. With aging occured differences of the charge of loading (absolute and relative) between the trained groups (YT greater than OT), body mass (increased among youth, increased initial mass and decreased final mass in the elderly), an increase in the right femur length, mineral material (calcium and phosphorus) and stiffness, however, a decrease of organic material. In this study, the training protocol did not cause effects on bone tissue chosen for analysis. In this study, the training protocol did not cause effects on bone tissue chosen for analysis. / A proposta deste estudo foi investigar a influência do treinamento resistido de alta intensidade sobre a atividade das metaloproteinases de matriz (MMPs), propriedades biométricas, biomecânicas, biofísicas e bioquímicas de ossos de ratos jovens e idosos. Foram utilizados 62 ratos intactos, Ratus novergicus albinos ( Wistar ), do gênero masculino, distribuídos aleatoriamente em 4 grupos: jovens sedentários (JS), jovens treinados (JT), idosos sedentários (IS) e idosos treinados (IT). Os ratos (JT e IT) realizaram treinamento resistido durante 12 semanas, que consistia em escalar em uma escada vertical de 1,1m com pesos fixados em suas caudas. As sessões foram realizadas três vezes por semana, em dias intercalados. As análises biomecânicas, biofísicas, bioquímicas e atividade da MMP-2 dos ossos foram realizadas, respectivamente, utilizou-se uma máquina de ensaio universal, princípio de Arquimedes, kit comercial específico e zimografia. No presente estudo, o protocolo de treinamento promoveu diminuição da massa corporal dos animais JT, e redução da rigidez óssea e da atividade da pro MMP-2 no grupo IT. Com o envelhecimento ocorreu diferenças da carga de carregamento (absoluta e relativa) entre os grupos treinados (JT maior que IT) e massa corporal (aumento nos jovens; aumento da massa inicial e diminuição da massa final nos idosos), aumento do comprimento do fêmur direito, material mineral (cálcio e fósforo) e rigidez, porém, uma diminuição do material orgânico. No presente estudo, o protocolo de treinamento não promoveu efeito sobre o tecido ósseo escolhido para análise.

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