Correlation between ultrasound velocity and densitometry in fresh and demineralized cortical bone

OBJECTIVE: To compare ultrasound propagation velocity with densitometry in the diaphyseal compact cortical bone of whole sheep metatarsals. METHODS: The transverse ultrasound velocity and bone mineral density of 5-cm-long diaphyseal bone segments were first measured. The bone segments were then divided into four groups of 15 segments each and demineralized in an aqueous 0.5 N hydrochloric acid solution for 6, 12, 24 or 36 hours. All measurements were repeated after demineralization for each time duration and the values measured before and after demineralization were compared. RESULTS: Ultrasound velocity and bone mineral density decreased with demineralization time, and most differences in the pre- and post-demineralization values within each group and between groups were significant: A moderate correlation coefficient (r=0.75956) together with a moderate agreement was determined between both post-demineralization parameters, detected by the Bland-Altman method. CONCLUSION: We conclude that both ultrasound velocity and bone mineral density decrease as a result of demineralization, thus indicating that bone mineral content is of great importance for maintaining the acoustic parameters of cortical bone, as observed for cancellous bone. Ultrasound velocity can be used to evaluate both compact cortical bone quality and bone mineral density.

Avaliação morfológica dos conjuntos guia excêntrico: placas dcp-l 4.5 mm / Morphological evaluation of eccentric sets guide-plates of dcp-l 4.5 mm

OBJETIVO: Avaliar isolada e comparativamente medidas do conjunto guia excêntrico-placa utilizado no material de 4.5mm e determinar sua influência na força de compressão. MÉTODOS: Foram utilizados quatros guias excêntricos e quatro placas largas de compressão dinâmica (DCP-L) de quatro fabricantes nacionais e um paquímetro digital Vonder®. Criou-se medidas-padrão para os conjuntos, totalizando cinco parâmetros, identificados de A a E. Os conjuntos foram formados por materiais da mesma fábrica e identificados de I a IV. As análises foram feitas com a visualização volar dos guias inseridos nas placas. As placas foram ensaiadas em máquina universal de ensaios. RESULTADOS: Os conjuntos I, II, apresentaram os mesmos valores em todas as medidas. Todos os conjuntos apresentaram os mesmos valores de E = 8.15 e B = 3.60. O conjunto III: A= 8.10mm, C=3.25mm e D= 1.25mm. O conj. IV: A = 7.00mm, C=3.10mm, D = 0.30mm. O conj. I apresentou Força de compressão máxima (F Max.) 80.58 N, conj. II: F Max. 81.63 N, conj. III: F Max. 36.32N, conj. IV: F Max. 37.52N. CONCLUSÃO: As medidas avaliadas nos conjuntos denotam a falta de padronização na fabricação de instrumentais ortopédicos e sua consequência nos valores da força de compressão. Nível de evidência III, estudo analítico.

OBJECTIVE: To carry out isolated and comparative evaluations of the measurements of the set eccentric guide plates used in 4.5mm surgical implants, and to determine the effect of these measurements on compression strength. METHODS: Four eccentric guides, (or guide plates?) four large dynamic compression plates (L-DCP) from four local manufacturers, and a Vonder® 200 mm caliper brand were used. Five standard parameter measurements were created for the set eccentric guide-plate, which were identified as A to E. Four sets were made, using materials of the same factory, and identified as groups I to IV. The analyses were performed by measuring all the parameters from a ventral view of the plate, with the eccentric guide placed in the plate hole. RESULTS: Groups I and II showed the same values for all the parameters. All the groups showed the same measurements for E = 8.15 e B = 3.60. Group III: A = 8.10mm, C = 3.25mm, D = 1.25mm. Group IV: A = 7.00mm, C = 3.10mm, D = 0.30mm. Maximum compression force was (F Max.): Group I 80.58 N, Group. II: F Max. 81.63 N, Group. III: F Max. 36.32N, Group. IV: F Max. 37.52N CONCLUSION: The measurements evaluated show a lack of standardization in the manufacture of orthopedic instruments and its effects on the values for compression strength. Level of Evidence: Level III, analytical study.

Lesões abdominais por uso do fio guia em ensaios cirúrgicos do quadril: estudo em cadáver / Abdominal injuries due to the use of guide wire in hip surgery experiments: cadaveric study

OBJETIVO: Avaliar a relação entre lesões abdominais e a introdução de fios guia em ensaios cirúrgicos do quadril, propor um sistema de escorização e conduta médica em função da distância percorrida pelo fio guia a partir da placa quadrilátera e a estrutura anatômica lesionada. MATERIAL E MÉTODOS: Utilizou-se 18 quadris de cadáveres, um fio de Steimann de 3.2 x 300 mm, um perfurador elétrico e um paquímetro. Introduziu-se o fio no centro do colo femoral por via de acesso lateral no quadril sob visualização direta. Por via de acesso abdominal mediana longitudinal estendida à região pélvica, observou-se a placa quadrilátera até o fio a transfixar. A partir deste ponto, prolongou-se a inserção por mais 140 mm, a fim de observar seu trajeto abdominal e descrever as lesões apresentadas em função da distância percorrida. RESULTADOS: Houve cinco (27 por cento) lesões de cólon sigmóide e uma (5 por cento) lesão transfixante do nervo obturador. Artérias e veias ilíacas comuns contra laterais ao quadril fixado não foram lesionadas. CONCLUSÃO: O fio guia não deve ultrapassar a placa quadrilátera. Medidas de prevenção são importantes no pré e intra-operatório e o escore e a conduta médica propostos neste estudo devem ser criteriosamente observados nos casos de lesão comprovada.

OBJECTIVES: Evaluate the relationship between abdominal injuries and the introduction of guide wire in experimental hip surgery, to propose a scoring system and a medical management based on the distance traveled by the guide wire from the quadrilateral plate until the damaged anatomical structure. MATERIAL AND METHODS: 18 cadaveric hips, a Steimann pin of 3.2 x 300mm, an electric drill and a caliper were used. The wire was inserted in the center of the femoral neck through a lateral approach in the hip under direct visualization. Via median abdominal extended approach to the pelvic region, the quadrilateral plate was observed until the wire crossed it. From this point the wire was further inserted 140 mm in order to observe its abdominal path and describe the lesions presented based on the distance traveled. RESULTS: There were five lesions (27 percent) in the sigmoid colon, and one transfixing injury (5 percent) of the obturator nerve. The common iliac arteries and veins from the contralateral hip were not injured. CONCLUSION: The guide wire must not exceed the quadrilateral plate. Preventive measures are important in the pre- and intra-operatory stages and the score and medical management proposed in this study should be carefully observed in cases of injury.