Axial compressive strength of human vertebrae trabecular bones classified as normal, osteopenic and osteoporotic by quantitative ultrasonometry of calcaneus

Abstract Introduction Biomechanical assessment of trabecular bone microarchitecture contributes to the evaluation of fractures risk associated with osteoporosis and plays a crucial role in planning preventive strategies. One of the most widely clinical technics used for osteoporosis diagnosis by health professionals is bone dual-energy X-ray absorptiometry (DEXA). However, doubts about its accuracy motivate the introduction of congruent technical analysis such as calcaneal ultrasonometry (Quantitative Ultrasonometry - QUS). Methods Correlations between Bone Quality Index (BQI), determined by calcaneal ultrasonometry of thirty (30) individuals classified as normal, osteopenic and osteoporotic, and elastic modulus (E) and ultimate compressive strength (UCS) from axial compression tests of ninety (90) proof bodies from human vertebrae trabecular bone, which were extracted from cadavers in the twelfth thoracic region (T12), first and fourth lumbar (L1 and L4). Results Analysis of variance (ANOVA) showed significant differences for E (p = 0.001), for UCS (p = 0.0001) and BQI. Spearman's rank correlation coefficient (rho) between BQI and E (r = 0.499) and BQI and UCS (r = 0.508) were moderate. Discussion Calcaneal ultrasonometry technique allowed a moderate estimate of bone mechanical strength and fracture risk associated with osteoporosis in human vertebrae.

Reparo de defeito osteocondral no joelho de coelhos utilizando centrifugado de medula óssea autóloga / Repair of osteochodral defect in the knee of rabbits using autologous bone marrow centrifuged

A cartilagem articular, por sua natureza avascular, apresenta uma capacidade limitada de regeneração. Uma abordagem terapêutica para o tratamento de defeitos da cartilagem consiste na utilização de células ou tecidos aplicados ao local da lesão. O objetivo deste estudo foi avaliar o efeito da aplicação de centrifugado de medula óssea autóloga em lesões osteocondrais no joelho de coelhos, em comparação com um grupo controle de lesões osteocondrais sem preenchimento, analisando o comportamento histológico destes grupos em função do tempo. Foram utilizados doze coelhos da raça Nova Zelândia, albinos, machos, adultos, submetidos a uma lesão osteocondral, de 4 mm de diâmetro e 3 mm de profundidade, em ambos os joelhos, na região da tróclea femoral. Nos joelhos direitos, que constituíram o Grupo Estudo, o defeito osteocondral foi preenchido por um coágulo de células mesenquimais, obtidas por centrifugação de um aspirado da medula óssea e selado com cola de fibrina. Nos joelhos esquerdos, que constituíram o Grupo Controle, o defeito osteocondral não recebeu qualquer preenchimento. Os animais foram divididos em três grupos de quatro coelhos, estudados após oito, 16 e 24 semanas. Os resultados foram descritos com base em uma escala de pontuação histológica que avaliou a morfologia celular, a reconstrução do osso subcondral, o aspecto da matriz, o preenchimento do defeito, a regularidade da superfície e a conexão das margens. A análise estatística foi realizada pelo Teste t-student para dados pareados na comparação entre Grupo Estudo e Grupo Controle. Para as comparações através do fator temporal, utilizou-se o Teste ANOVA one way. Com 5% de confiança, rejeitou-se a hipótese de igualdade entre os Grupos Estudo e Controle. Notou-se uma distância decrescente entre os escores dos Grupos Estudo e Controle com o aumento do tempo, bem como uma tendência crescente do valor da escala para o Grupo Controle. Concluiu-se que a aplicação de centrifugado de medula óssea...

The articular cartilage, due to its avascular nature, presents a limited regeneration capacity. A therapeutical approach to the treatment of cartilage defects consists of the utilization of cells or tissues applied to the lesion site. The aim of this study was to evaluate the effect of applying autologous bone marrow centrifuged in osteochondral lesions in the knees of rabbits, compared to a control group of osteochondral lesions without any filling, analyzing the behavior of these groups in terms of time. Twelve adult albino male New Zealand rabbits were used being submitted to an osteochondral lesion of 4 mm in diameter and 3 mm deep in both knees, at the femoral trochlea area. On the right knees, which comprised the Study Group, the osteochondral defect was filled by a clot of mesenchymal cells, obtained by centrifugation of an aspirate from bone marrow and sealed with fibrin glue. On the left knees, which comprised the Control Group, the osteochondral defect did not get any filling. The animals were divided into 3 groups of 4 rabbits, and studied after eight, 16 and 24 weeks. The results were described based on a histological grading scale which took into account the cell morphology, the subchondral bone reconstruction, the matrix staining, the filling of the defect, the surface regularity and the bonding of the edges. The statistical analysis was made by the t-student Test for paired data in the comparison between the Study Group and the Control Group. For the comparisons made by the time factor, it was used the ANOVA Test one way. With 5% level of confidence, the hypothesis of equality between the Study and Control Groups was rejected. It was observed a decreasing distance between scores of the Study and Control Groups as time increased, as well as an increasing tendency of the scale value for the Control Group. It was concluded that the application of autologous bone marrow centrifuged in osteochondral defects in the knees of rabbits showed better...

Estudo comparativo de propriedades biomecânicas da porção central do tendão calcâneo congelado e a fresco / Comparative study on biomechanical properties of the central portion of frozen and fresh calcaneus tendon

Métodos de armazenamento de aloenxertos podem alterar certas características mecânicas dos tecidos. Com o objetivo de analisar a influência do fenômeno de congelamento e do tempo de armazenamento sobre as propriedades biomecânicas de tendões, os autores estudaram 40 tendões calcâneos obtidos de 20 cadáveres humanos com idade média de 41,95 anos, variando de 31 a 54 anos, sendo 17 do sexo masculino e três do sexo feminino. De cada cadáver foram retirados dois tendões, sendo que um foi testado a fresco e o contralateral congelado a - 85° C em freezer elétrico, durante um período de seis ou 12 semanas. Os corpos de prova foram submetidos a ensaios de tração em uma máquina de ensaios mecânicos Kratos K5002, fornecendo gráficos força-deformação. Foram analisados os parâmetros de força no limite de resistência máxima, rigidez, tensão no limite de resistência máxima, deformação relativa e módulo de elasticidade. Os resultados foram comparados e a analisados estatisticamente pelo método de "t-student", com índice de significância de 0,05, sendo que não houve diferença significativa nos valores obtidos entre os grupos. Concluímos que o congelamento a - 85° C não altera as propriedades biomecânicas de tendões, a despeito do tempo de armazenamento.

Allograft storage methods can change some mechanical characteristics of tissues. With the objective of analyzing the influence of freezing phenomenon and storage time on tendonsÆ biomechanical properties, the authors studied 40 calcaneus tendons obtained from 20 human cadavers, with an average age of 41.95 years, ranging from 31 to 54 years old, being 17 males and three females. From each cadaver, two tendons were removed, one tested in its fresh state and the contralateral one frozen at -85° C in an electric freezer, during a period of six or 12 weeks. The bodies of evidence were submitted to traction assays in a Kratos K5002 mechanical assay machine, delivering strength-deformation graphics. Strength at maximum resistance limit, stiffness, tension at maximum resistance limit, relative deformation, and elasticity module parameters were assessed. The results were compared and statistically analyzed by "StudentÆs t- method", with a significance level of 0.05, with no significant difference on values achieved between groups. We concluded that freezing at -85° C does not cause changes to tendonsÆ biomechanical properties, despite of storage time.

Trombose venosa profunda em artroplastia total de quadril / Deep venous thrombosis in total hip arthroplasty

Total hip arthroplasty is a common surgical procedure in a population with the organic frailty of aging. Deep venous thrombosis and pulmonary thromboembolism are the more common and dangerous complications of this procedure. Therefore, surgeon knowledge of diagnosis, prevention and treatment of these complications is mandatory both technically and ethically. The authors make a descriptive and critical revision of the literature regarding the most recent acquisitions in diagnosid, prevention, and treatment of these complications