Three-Dimensional Printed Laryngoscopes as Allies Against COVID-19.

The COVID-19 pandemic has caused an overload on the health care system on a global scale. Because the disease affects the respiratory system, patients may require ventilator equipment for breathing, and consequently, numerous tracheal intubations have been performed. The video laryngoscope is a medical device that aids this procedure. It is used by anesthesiologists to visualize the anatomical structures of the larynx during tube insertion. Unfortunately, many hospitals worldwide are unable to afford sufficient units of this medical device. To satisfy the high demand, low-cost alternatives employing three-dimensional (3D) printing techniques have been developed for health care professional's use. With the intention of ensuring the efficiency, reproducibility, and security of the 3D-printed laryngoscope, this article presents a novel model with versions for pediatric and adult use, which was developed under the supervision of a medical team. The mechanical performance of 3D-printed prototypes (of the proposed models) was evaluated using mechanical assays, and the results indicated a satisfactory safety factor.

Comparative Study with and without the Use of 3D Prototyping of an Unconventional Technique in the Surgical Planning of Revision of Total Hip Arthroplasty.

This article presents a comparison between two cases in which there was a need for revision of total hip arthroplasty due to aseptic acetabular failure. We used 3D prototyping in one of the cases to perform an unconventional technique of molding synthesis material before the procedure to evaluate the time saved in the transoperative period in complex cases.

Comparative Study with and without the Use of 3D Prototyping of an Unconventional Technique in the Surgical Planning of Revision of Total Hip Arthroplasty / Estudo comparativo com e sem o uso de prototipagem em 3D de uma técnica não convencional no planejamento cirúrgico de revisão de artroplastia total de quadril

Abstract This article presents a comparison between two cases in which there was a need for revision of total hip arthroplasty due to aseptic acetabular failure. We used 3D prototyping in one of the cases to perform an unconventional technique of molding synthesis material before the procedure to evaluate the time saved in the transoperative period in complex cases.

Resumo Este artigo apresenta uma comparação entre dois casos em que havia a necessidade de revisão de artroplastia total de quadril por falha acetabular asséptica. Utilizamos prototipagem em 3D em um dos casos para realizar uma técnica não convencional de moldagem de material de síntese antes do procedimento, com objetivo de avaliar o tempo economizado no transoperatório em casos complexos.

Radiographic Evaluation of Postoperative Alignment in Total Knee Arthroplasty.

Objective To demonstrate the greater accuracy of panoramic radiographs of the lower limbs (long) in relation to short radiographs of the knee in the measurement of the mechanical axis of the lower limb after total knee arthroplasty (TKA). Methods A retrospective study was conducted to evaluate the accuracy of long and short postoperative radiographic images of 70 patients submitted to TKA in our service. The images were analyzed at random, at different times, by three orthopedists. In all images, the mechanical axis of the limb, femur and tibia were traced and femorotibial angles (FTAs) were calculated. The intraclass correlation coefficient (ICC) was calculated to evaluate the agreement of the measurement of the inter- and intra-observer mechanical axis. Results It was observed that there was high intra and interobserver agreement when panoramic radiographs were used, with minimum intra and interobserver ICC of 0.89, equivalent to a very strong agreement. On short radiographs in the anteroposterior incidence (AP) of the knee, the ICC showed moderate agreement, obtaining a maximum value of 0.75. Conclusion There is a significant difference in accuracy for the measurement of the mechanical axis of the lower limb, comparing long and short radiographs of the lower limb. Thus, for the proper measurement of the mechanical axis of the lower limb, we suggest the performance of long radiography in the postoperative period of TKA.

Radiographic Evaluation of Postoperative Alignment in Total Knee Arthroplasty / Avaliação radiográfica do alinhamento pós-operatório na artroplastia total de joelho

Abstract Objective To demonstrate the greater accuracy of panoramic radiographs of the lower limbs (long) in relation to short radiographs of the knee in the measurement of the mechanical axis of the lower limb after total knee arthroplasty (TKA). Methods A retrospective study was conducted to evaluate the accuracy of long and short postoperative radiographic images of 70 patients submitted to TKA in our service. The images were analyzed at random, at different times, by three orthopedists. In all images, the mechanical axis of the limb, femur and tibia were traced and femorotibial angles (FTAs) were calculated. The intraclass correlation coefficient (ICC) was calculated to evaluate the agreement of the measurement of the inter- and intra-observer mechanical axis. Results It was observed that there was high intra and interobserver agreement when panoramic radiographs were used, with minimum intra and interobserver ICC of 0.89, equivalent to a very strong agreement. On short radiographs in the anteroposterior incidence (AP) of the knee, the ICC showed moderate agreement, obtaining a maximum value of 0.75. Conclusion There is a significant difference in accuracy for the measurement of the mechanical axis of the lower limb, comparing long and short radiographs of the lower limb. Thus, for the proper measurement of the mechanical axis of the lower limb, we suggest the performance of long radiography in the postoperative period of TKA.

Resumo Objetivo Demonstrar a maior acurácia das radiografias panorâmicas de membros inferiores (longas) em relação às radiografias curtas do joelho na medida do eixo mecânico do membro inferior após a artroplastia total de joelho (ATJ). Métodos Foi realizado um estudo retrospectivo para avaliar a acurácia de imagens radiográficas longas e curtas pós-operatórias de 70 pacientes submetidos à ATJ em nosso serviço. As imagens foram analisadas ao acaso, em momentos distintos, por três ortopedistas. Em todas as imagens, o eixo mecânico do membro, do fêmur e da tíbia foram traçado,s e os ângulos femorotibiais (AFTs) foram calculados. O coeficiente de correlação intraclasse (CCI) foi calculado para avaliar a concordância da medida do eixo mecânico inter e intraobservador. Resultados Observou-se que houve alta concordância intra e interobservador quando utilizamos radiografias panorâmicas, apresentando CCI mínimo intrae interobservador de 0,89, equivalente a uma concordância fortíssima. Já nas radiografias curtas na incidência anteroposterior (AP) do joelho, o CCI mostrou-se com concordância moderada, obtendo valor máximo de 0,75. Conclusão Existe uma diferença significativa na acurácia para a medida do eixo mecânico do membro inferior, comparando-se radiografias longas e curtas do membro inferior. Assim, para a adequada mensuração do eixo mecânico do membro inferior, sugerimos a realização de radiografia longa no pós-operatório de ATJ.

INFLUENCE OF FEMORAL OFFSET ON FUNCTIONAL CAPACITY OF PATIENTS WITH TOTAL HIP ARTHROPLASTY.

Objective: To correlate vertical (VFO) and horizontal (HFO) femoral offset with hip range of motion (ROM), peak muscle torque (PT), functional, capacity, and lower limb length in patients with total hip arthroplasty (THA). Methods: A cross-sectional case control study, in which 22 individuals (10 men and 12 women) - aged 61 (41-72), and within 23 (10-40) postoperative days - were evaluated for active hip ROM (fleximetry); Isometric PT (portable dynamometer); functional capacity (Timed up and Go test (TUG) and Harris Hip Score questionnaire); lower limb length (measuring tape); and VFO and HFO (radiographs). Results: The operated limb showed a reduction in length (p = 0.006), ROM for abduction (p = 0.001), flexion (p = 0.003), and external rotation (p = 0.003), as well as in all PT (p < 0.05) when compared with the contralateral limb. Moderate correlations were observed between VFO and external rotators (r = 0.487; p = 0.021); HFO and external rotators PT (r = -0.508; p = 0.016); and the difference between the VFO (operated and non-operated limb) and the TUG (r = -0.570; p = 0.006). Conclusion: Changes to the femoral offset seem to influence functional capacity, as well as the movement and external rotators PT of the hips in patients with THA, considering the postoperative period evaluated. Level of Evidence III, Case Control Study.

Objetivo: Correlacionar achados do offset femoral vertical (OFV) e horizontal (OFH) aos da amplitude de movimento do quadril (ADM), pico de torque muscular (PT), capacidade funcional (CF) e comprimento dos membros inferiores (CM) em pacientes com artroplastia total de quadril (ATQ). Métodos: Estudo transversal, caso controle (nível de evidência III), foram avaliados 22 indivíduos (10 homens e 12 mulheres) com idade de 61 (41-72) anos e 23 (10-40) dias de pós-operatório, quanto à: ADM ativa do quadril (fleximetria); PT isométrico (dinamômetro portátil); CF - teste Timed up and Go (TUG) e questionário Harris Hip Score (HHS); CM (fita métrica); e OFV e OFH a partir de radiografias. Resultados: O membro operado apresentou redução no CM (p = 0,006), ADM de abdução (p = 0,001), flexão (p = 0,003) e RE (p = 0,003), e em todos os PT (p < 0,05) em comparação ao membro contralateral. Correlações moderadas encontradas entre: OFV e RE (r = 0,487; p = 0,021); OFH e PT dos RE (r = −0,508; p = 0,016);e a diferença do OFV (membro operado e não operado) e o TUG (r = −0,570; p = 0,006). Conclusão: Alterações no OF parecem influenciar a CF, bem como o movimento e o PT dos RE do quadril em pacientes com ATQ para o período pós-operatório avaliado. Nível de Evidência III, Estudo de Caso-Controle.

Influence of femoral offset on functional capacity of patients with total hip arthroplasty / Influência do offset femoral na capacidade funcional de pacientes com artroplastia total de quadril

ABSTRACT Objective: To correlate vertical (VFO) and horizontal (HFO) femoral offset with hip range of motion (ROM), peak muscle torque (PT), functional, capacity, and lower limb length in patients with total hip arthroplasty (THA). Methods: A cross-sectional case control study, in which 22 individuals (10 men and 12 women) - aged 61 (41-72), and within 23 (10-40) postoperative days - were evaluated for active hip ROM (fleximetry); Isometric PT (portable dynamometer); functional capacity (Timed up and Go test (TUG) and Harris Hip Score questionnaire); lower limb length (measuring tape); and VFO and HFO (radiographs). Results: The operated limb showed a reduction in length (p = 0.006), ROM for abduction (p = 0.001), flexion (p = 0.003), and external rotation (p = 0.003), as well as in all PT (p < 0.05) when compared with the contralateral limb. Moderate correlations were observed between VFO and external rotators (r = 0.487; p = 0.021); HFO and external rotators PT (r = −0.508; p = 0.016); and the difference between the VFO (operated and non-operated limb) and the TUG (r = −0.570; p = 0.006). Conclusion: Changes to the femoral offset seem to influence functional capacity, as well as the movement and external rotators PT of the hips in patients with THA, considering the postoperative period evaluated. Level of Evidence III, Case Control Study.

RESUMO Objetivo: Correlacionar achados do offset femoral vertical (OFV) e horizontal (OFH) aos da amplitude de movimento do quadril (ADM), pico de torque muscular (PT), capacidade funcional (CF) e comprimento dos membros inferiores (CM) em pacientes com artroplastia total de quadril (ATQ). Métodos: Estudo transversal, caso controle (nível de evidência III), foram avaliados 22 indivíduos (10 homens e 12 mulheres) com idade de 61 (41-72) anos e 23 (10-40) dias de pós-operatório, quanto à: ADM ativa do quadril (fleximetria); PT isométrico (dinamômetro portátil); CF - teste Timed up and Go (TUG) e questionário Harris Hip Score (HHS); CM (fita métrica); e OFV e OFH a partir de radiografias. Resultados: O membro operado apresentou redução no CM (p = 0,006), ADM de abdução (p = 0,001), flexão (p = 0,003) e RE (p = 0,003), e em todos os PT (p < 0,05) em comparação ao membro contralateral. Correlações moderadas encontradas entre: OFV e RE (r = 0,487; p = 0,021); OFH e PT dos RE (r = −0,508; p = 0,016); e a diferença do OFV (membro operado e não operado) e o TUG (r = −0,570; p = 0,006). Conclusão: Alterações no OF parecem influenciar a CF, bem como o movimento e o PT dos RE do quadril em pacientes com ATQ para o período pós-operatório avaliado. Nível de Evidência III, Estudo de Caso-Controle.

Use of 3D Printing in Planning the Reconstruction of Total Hip Arthroplasty: A Teaching Tool.

The present study aims to demonstrate how biomodels can be used as teaching tools for surgical techniques and training in a medical residency service. A case series was carried out in our orthopedics and traumatology outpatient facility using three-dimensional (3D) printing for surgical planning to contribute to the surgical teaching and training of resident physicians. Two cases were selected as examples in the present article. Biomodels enable a better understanding of the surgery by the surgical team and residents, reducing the surgical time and the risks for the patients. These models can be a good teaching method to plan reconstructions of total hip arthroplasties, evaluate and predict surgical difficulties, and optimize procedures.

Use of 3D Printing in Planning the Reconstruction of Total Hip Arthroplasty: A Teaching Tool / Uso de prototipagem rápida no planejamento de reconstruções da artroplastia total do quadril: Uma ferramenta para ensino

Abstract The present study aims to demonstrate how biomodels can be used as teaching tools for surgical techniques and training in a medical residency service. A case series was carried out in our orthopedics and traumatology outpatient facility using three-dimensional (3D) printing for surgical planning to contribute to the surgical teaching and training of resident physicians. Two cases were selected as examples in the present article. Biomodels enable a better understanding of the surgery by the surgical team and residents, reducing the surgical time and the risks for the patients. These models can be a good teaching method to plan reconstructions of total hip arthroplasties, evaluate and predict surgical difficulties, and optimize procedures.

Resumo O objetivo deste trabalho é demonstrar como os biomodelos podem servir como ferramenta de ensino para o esclarecimento de técnicas cirúrgicas e o treinamento em um serviço de residência médica. Foram realizadas séries de casos em nosso ambulatório de ortopedia e traumatologia, nos quais o uso da prototipagem para o planejamento cirúrgico contribuiu para o ensino cirúrgico e treinamento de médicos residentes. Dois casos foram selecionados como exemplo neste artigo. O uso de biomodelos permite um melhor entendimento da cirurgia pela equipe cirúrgica e pelos residentes, e diminui o tempo e os riscos cirúrgicos aos pacientes. O uso de biomodelos no planejamento de reconstruções da artroplastia total do quadril pode servir como um bom método de ensino, para a avaliação e previsão das dificuldades no momento da cirurgia, e para otimizar os procedimentos.

New proposal for the treatment of coronal split fractures in lumbar vertebrae: the fatigue curve / Nova proposta de tratamento de fraturas do tipo split coronal em vértebras lombares: curva de fadiga / Nueva propuesta de tratamiento de fracturas del tipo split coronal en vértebras lumbares: curva de fatiga

ABSTRACT Objective: To evaluate a new treatment for split fractures through fatigue tests on a swine model. Methods: Thirty lumbar spine samples (L2-L3-L4) from swine models were divided into three test groups. The first was the control group (intact vertebrae). In the second group, a bone defect was created, similar to a coronal split fracture of the vertebral body. For this, a bone defect (osteotomy) was performed in the coronal axis of the middle third of the middle lumbar vertebral body (L3), keeping the disc-ligament structures intact. In the third group, the same procedure was performed to cause bone failure, but was associated with the use of synthesis material, with pedicular fixation using 3.5 mm cannulated screws with partial thread, in order to apply compression at the fracture site, giving resistance and support to the vertebra. The groups were submitted to biomechanical fatigue tests. The number of cycles required to failure in the specimen was analyzed. Results: The use of the synthesis material increased the resistance of the fractured vertebrae to levels equal to those of the intact vertebra for low cycles with loads of 40% of the failure load, possibly losing up to 20% of their resistance for higher cycles. Conclusions: In the vertebrae in which synthetic material was used, greater resistance to a greater number of cycles for a longer period of time was observed when compared with the fractured vertebrae, suggesting that this is an interesting method for the fixation of split-type spinal fractures. Level of evidence III; Experimental Study.

RESUMO Objetivo: Avaliar um novo tratamento de fraturas do tipo separação (split) através de ensaios de fadiga em modelo suíno. Métodos: Trinta amostras de coluna lombar (L2-L3-L4) de modelos suínos foram divididas em três grupos para testes. O primeiro constituiu o grupo controle (vértebras intactas). No segundo grupo, foi criado um defeito ósseo semelhante a uma fratura split coronal do corpo vertebral. Para tanto, criou-se um defeito ósseo (osteotomia) no eixo coronal do terço médio do corpo vertebral intermediário lombar (L3), mantendo as estruturas disco-ligamentares íntegras. No terceiro grupo, foi realizado o mesmo procedimento para causar a falha óssea, sendo associado o uso de material de síntese, com a fixação pedicular com parafuso canulado de 3,5 mm com rosca parcial, com objetivo de realizar compressão no foco da fratura e dar resistência e sustentação à vertebra. Os grupos foram submetidos a testes biomecânicos de fadiga. Foi analisado o número de ciclos necessários para que ocorresse a falha no corpo de prova. Resultados: O material de síntese aumenta a resistência da vértebra fraturada em níveis iguais aos da vértebra intacta para baixos ciclos e com cargas de 40% da tensão de ruptura, podendo perder até 20% de sua resistência para ciclos mais altos. Conclusões: Nas vértebras em que foi utilizado material de síntese observou-se maior resistência ao maior número de ciclos por um período mais prolongado em comparação com as vértebras apenas fraturadas, sugerindo que este é um método interessante para a fixação de fraturas do tipo split na coluna vertebral. Nível de evidência III; Estudo experimental.

RESUMEN Objetivo: Evaluar un nuevo tratamiento de fracturas lumbares del tipo separación (split) a través de ensayos de fatiga en modelo porcino. Métodos: Treinta muestras de columna lumbar (L2-L3-L4) de modelos porcinos fueron divididas en tres grupos para tests. El primero constituyó el grupo control (vértebras intactas). En el segundo grupo, fue creado un defecto óseo semejante a una fractura split coronal del cuerpo vertebral. Para tanto, se creó un defecto óseo (osteotomía) en el eje coronal del tercio medio del cuerpo vertebral intermedio lumbar (L3), manteniendo las estructuras disco-ligamentarias íntegras. En el tercer grupo, fue realizado el mismo procedimiento para causar la falla ósea, siendo asociado el uso de material de síntesis, con fijación pedicular con tornillo canulado de 3,5 mm con rosca parcial, con el objetivo de realizar compresión en el foco de la fractura y dar resistencia y sustentación a la vértebra. Los grupos fueron sometidos a tests biomecánicos de fatiga. Fue analizado el número de ciclos necesarios para que ocurriese la falla en el cuerpo de prueba. Resultados: El material de síntesis aumenta la resistencia de la vértebra fracturada en niveles iguales a los de la vértebra intacta para bajos ciclos y con cargas de 40% de la tensión de ruptura, pudiendo perder hasta 20% de su resistencia para ciclos más altos. Conclusiones: En las vértebras en que fue utilizado material de síntesis se observó mayor resistencia al mayor número de ciclos por un período más prolongado en comparación con las vértebras solamente fracturadas, sugiriendo que este es un método interesante para la fijación de fracturas de tipo split en columna vertebral. Nivel de evidencia III; Estudio experimental.

Split-type fractures of the spine: a new minimally invasive percutaneous technique / Fraturas tipo split da coluna: nova técnica percutânea minimamente invasiva / Fracturas tipo split de la columna: nueva técnica percutánea mínimamente invasiva

ABSTRACT Objective: This research presents a biomechanical analysis performed in the lumbar spine of a porcine animal model, considering a minimally invasive technique for the treatment of split fractures. Methods: Porcine spines were used to perform compression tests, considering three different approaches. Three groups were defined in order to verify and validate the proposed technique: a control group (1); spines with split fractures (2); and a treatment group (3). For the first group (control), spines were axially compressed until any kind of fracture occurred, in order to verify the strength of the structure. In the second group, split fractures were created to obtain the mechanical failure pattern of the model. In the third group, the split fractures were submitted to the proposed treatment, to verify the resistance achieved. The three groups were compared by means of axial compression tests. Statistical analysis was performed by ANOVA. Results: The control group (intact spine) and the treated split fracture group presented similar results (p>0.05), differing from the results for the untreated split fracture group (p<0.05). Conclusions: The tests performed in order to determine the behavior and strength of the lumbar spine when subjected to axial compression provided positive data for the development of a minimally invasive technique capable of restoring split fractures of the spine. Level of evidence III; Experimental research.

RESUMO Objetivo: Esta pesquisa apresenta uma análise biomecânica realizada na coluna lombar em modelo animal suíno, considerando uma técnica minimamente invasiva para o tratamento de fraturas vertebrais do tipo split. Métodos: Foram usadas colunas de suínos para a realização de testes de compressão, considerando três diferentes abordagens. Para verificar e validar a técnica proposta, foram definidos três grupos: grupo controle (1); colunas com fraturas do tipo split (2) e grupo tratamento (3). No o primeiro grupo (controle), as colunas foram comprimidas axialmente até que ocorresse qualquer tipo de fratura, a fim de verificar a resistência da estrutura. No segundo grupo, foram criadas fraturas do tipo split para obter o padrão de falha mecânica do modelo. No terceiro grupo, as fraturas do tipo split foram submetidas ao tratamento proposto, para verificar a resistência alcançada. Os três grupos foram comparados por meio de testes de compressão axial. A análise estatística foi realizada por ANOVA. Resultados: O grupo controle (coluna íntegra) e o grupo com fratura do tipo split tratada apresentaram resultados semelhantes (p > 0,05), diferentemente dos resultados do grupo com fratura do tipo split não tratada (p < 0,05). Conclusões: Os testes para determinar o comportamento e a força da coluna lombar quando é submetida à compressão axial forneceram dados positivos para o desenvolvimento de uma técnica minimamente invasiva capaz de restaurar fraturas tipo split da coluna vertebral. Nível de evidência III; Pesquisa experimental.

RESUMEN Objetivo: Esta investigación presenta un análisis biomecánico realizado en la columna lumbar de un modelo animal porcino, considerando una técnica mínimamente invasiva para el tratamiento de fracturas vertebrales del tipo split. Métodos: Fueron usadas columnas de porcinos para la realización de tests de compresión, considerando tres diferentes abordajes. Para verificar y validar la técnica propuesta, fueron definidos tres grupos: grupo control (1); columnas con fracturas del tipo split (2) y grupo tratamiento (3). En el primer grupo (control), las columnas fueron comprimidas axialmente hasta que ocurriera cualquier tipo de fractura, a fin de verificar la resistencia de la estructura. En el segundo grupo, fueron creadas fracturas del tipo split para obtener el patrón de falla mecánica del modelo. En el tercer grupo, las fracturas del tipo split fueron sometidas al tratamiento propuesto, para verificar la resistencia alcanzada. Los tres grupos fueron comparados por medio de tests de compresión axial. El análisis estadístico fue realizado por ANOVA. Resultados: El grupo control (columna íntegra) y el grupo con fractura del tipo split tratada presentaron resultados semejantes (p>0,05), a diferencia de los resultados del grupo con fractura del tipo Split no tratada (p<0,05). Conclusiones: Los tests para determinar el comportamiento y la fuerza de la columna lumbar cuando es sometida a la compresión axial suministraron datos positivos para el desarrollo de una técnica mínimamente invasiva, capaz de restaurar fracturas del tipo Split de la columna vertebral. Nivel de evidencia III; Investigación experimental.

Biomechanical Study of Different Femoral Fixation Devices in the Reconstruction of the Medial Patellofemoral Ligament in Porcine Knees.

Objective To evaluate different femoral fixation devices for medial patellofemoral ligament reconstruction and compare their effectiveness regarding fixation strength up to failure in porcine knees. Methods Thirty porcine knees were used, divided into three groups of 10 knees. The removed grafts were dissected from the extensor tendons of porcine feet. In each group, the graft was fixed to the femur with an interference screw, an anchor, or adductor tenodesis. The three methods were subjected to biomechanical tests using a universal Tensile testing machine at a speed of 20 mm/minute. Results The highest average linear resistance under lateral traction occurred in group 1, "screw fixation" (185.45 ± 41.22 N), followed by group 2, "anchor fixation" (152.97 ± 49, 43 N); the lower average was observed in group 3, "tenodesis fixation" (76.69 ± 18.90 N). According to the fixed error margin (5%), there was a significant difference between groups ( p < 0.001); in addition, multiple comparison tests (between group pairs) also showed significant differences. Variability was small, since the variance coefficient was lower than 33.3%. Conclusion Interference screws in bone tunnels and mountable anchors fixation with high resistance wire are strong enough for femoral fixation in porcine medial patellofemoral ligament reconstruction. Adductor tenodesis, however, was deemed fragile for such purpose.

Biomechanical Study of Different Femoral Fixation Devices in the Reconstruction of the Medial Patellofemoral Ligament in Porcine Knees / Estudo biomecânico de diferentes dispositivos de fixação femoral na reconstrução do ligamento patelofemoral medial em joelhos de suínos

Abstract Objective To evaluate different femoral fixation devices for medial patellofemoral ligament reconstruction and compare their effectiveness regarding fixation strength up to failure in porcine knees. Methods Thirty porcine knees were used, divided into three groups of 10 knees. The removed grafts were dissected from the extensor tendons of porcine feet. In each group, the graft was fixed to the femur with an interference screw, an anchor, or adductor tenodesis. The three methods were subjected to biomechanical tests using a universal Tensile testing machine at a speed of 20 mm/minute. Results The highest average linear resistance under lateral traction occurred in group 1, "screw fixation" (185.45 ± 41.22 N), followed by group 2, "anchor fixation" (152.97 ± 49, 43 N); the lower average was observed in group 3, "tenodesis fixation" (76.69 ± 18.90 N). According to the fixed error margin (5%), there was a significant difference between groups (p < 0.001); in addition, multiple comparison tests (between group pairs) also showed significant differences. Variability was small, since the variance coefficient was lower than 33.3%. Conclusion Interference screws in bone tunnels and mountable anchors fixation with high resistance wire are strong enough for femoral fixation in porcine medial patellofemoral ligament reconstruction. Adductor tenodesis, however, was deemed fragile for such purpose.

Resumo Objetivo Avaliar diferentes dispositivos de fixação femoral na reconstrução do ligamento patelofemoral medial para comparar sua eficácia quanto à força de fixação até a falha em joelhos suínos. Métodos Foram ensaiados 30 joelhos de suínos subdivididos em 3 grupos de 10 joelhos. Os enxertos retirados foram dissecados de tendões extensores das patas dos suínos. Cada grupo teve o enxerto fixado ao fêmur com parafuso de interferência, âncora, ou tenodese no tendão adutor. Os 3 métodos foram submetidos à testes biomecânicos utilizando uma máquina universal de ensaio de tração com uma velocidade de 20 mm/min. Resultados Verificamos que a média mais elevada da resistência linear sob tração lateral (185,45 ± 41,22 N) ocorreu no grupo 1: "fixação por parafuso," seguido do grupo 2: "fixação por âncora" (152,97 ± 49,43 N), e a média foi menor no grupo 3: "fixação por tenodese" (76,69 ± 18,90 N). Para a margem de erro fixada (5%), comprovou-se a diferença significativa entre os grupos (p < 0,001) e também através dos testes de comparações múltiplas (entre os pares de grupos) verificou-se a ocorrência de diferenças significativas. A variabilidade expressada por meio do coeficiente de variação mostrou-se reduzida, já que a referida medida foi inferior a 33,3%. Conclusão O uso de parafusos de interferência no túnel ósseo de joelhos porcinos é suficientemente forte para fixação femoral na reconstrução do ligamento patelofemoral medial, assim como a fixação com âncoras montáveis com fio de alta resistência. Entretanto, a tenodese no tendão adutor mostrou-se frágil para essa finalidade.

Mechanical behavior of thoracolumbar coronal split fractures: finite element analysis / Comportamento mecânico das fraturas toracolombares do tipo split coronal: estudo por elementos finitos / Comportamiento mecánico de las fracturas toracolumbares del tipo split coronal: estudio por elementos finitos

ABSTRACT Objective To analyze the behavior of thoracolumbar fractures of the coronal split type using the finite element method. Methods Two comparative studies were conducted through simulation of coronal split fractures in a finite model in which the first lumbar vertebra (L1) was considered to be fractured. In the first case, the fracture line was considered to have occurred in the middle of the vertebral body (50%), while in the second model, the fracture line occurred in the anterior quarter of the vertebral body (25%). The maximum von Mises stress values were compared, as well as the axial displacement between fragments of the fractured vertebra. Results The stress levels found for the fracture located at half of the vertebral body were 43% higher (264.88 MPa x 151.16 MPa) than those for the fracture located at the anterior 25% of the vertebra, and the axial displacement of the 50% fractured body was also greater (1.19 mm x 1.10 mm). Conclusions Coronal split fractures located in the anterior quarter of the vertebral body incurred less stress and displacements and are more amenable to conservative treatment than 50% fractures occurring in the middle of the vertebral body. Level of Evidence III; Experimental study.

RESUMO Objetivo Analisar o comportamento das fraturas toracolombares do tipo split coronal através de elementos finitos. Métodos Foram realizados dois estudos comparativos através da simulação de fratura do tipo split coronal, em modelo finito, considerando que a primeira vértebra lombar (L1) estava fraturada. No primeiro caso, considerou-se que o traço da fratura ocorria na metade do corpo vertebral (50%), já no segundo modelo, o traço de fratura ocorria na porção anterior do corpo (25%). Foram comparados os valores de tensão máxima segundo von Mises, assim como o deslocamento axial sofrido entre os fragmentos da vértebra fraturada. Resultados Na fratura localizada ao nível da metade do corpo vertebral, os níveis de tensões encontrados foram 43% maiores (264,88 MPa x 151,16 MPa) do que aqueles na fratura a 25% no terço anterior do corpo vertebral, em que o deslocamento axial da porção fraturada também foi mais elevado (1,19 mm x 1,10 mm). Conclusões As fraturas do tipo split coronal localizadas no quarto anterior do corpo vertebral concentram menos tensões e deslocamentos, sendo mais passíveis de tratamento conservador em comparação às fraturas que ocorrem na metade do corpo vertebral. Nível de Evidência III; Estudo experimental.

RESUMEN Objetivo Analizar el comportamiento de las fracturas toracolumbares del tipo split coronal a través de elementos finitos. Métodos Se realizaron dos estudios comparativos a través de la simulación de fractura del tipo split coronal, en modelo finito, considerando que la primera vértebra lumbar (L1) estaba fracturada. En el primer caso, se consideró que el trazo de la fractura ocurría en la mitad del cuerpo vertebral (50%), ya en el segundo modelo, el trazo de la fractura ocurría en la porción anterior del cuerpo (25%). Fueron comparados los valores de tensión máxima según von Mises, así como el desplazamiento axial sufrido entre los fragmentos de la vértebra fracturada. Resultados En la fractura localizada al nivel de la mitad del cuerpo vertebral, los niveles de tensiones encontrados fueron 43% mayores (264,88 MPa x 151,16 MPa) que aquellos en la fractura a 25% en el tercio anterior del cuerpo vertebral, en que el desplazamiento axial de la porción fracturada fue también más elevado (1,19 mm x 1,10 mm). Conclusiones Las fracturas del tipo split coronal localizadas en el cuarto anterior del cuerpo vertebral concentran menores tensiones y desplazamientos, siendo más susceptibles de tratamiento conservador en comparación a las fracturas que ocurren en la mitad del cuerpo vertebral. Nivel de Evidencia III; Estudio experimental.

Reliability-Based Design Optimization of a Cemented Prosthesis in a Femur Undergoing Bone Remodeling.

This study proposes a numerical methodology to minimize the bone mass loss in a femur with a total hip arthroplasty procedure, considering uncertainties in the material parameters and using a reliability-based design optimization (RBDO) procedure. A genetic algorithm (GA) is applied for optimization, and a three-dimensional finite element (FE) model associated with the bone remodeling procedure is proposed and described to account for the internal and external femoral bone behavior. An example of a femoral prosthesis design is presented as a basis for discussion of the proposed methodologies, and the corresponding reliability level is evaluated. Constraints on the strength of all materials and target reliability levels are inputs to the optimization model. The main prosthesis dimensions and Young modulus are the design variables. The proposed methodology is compared with a well-known deterministic optimization (DO) procedure and the results show that it is important to consider the uncertainties in this kind of problem since in this case, the a posteriori reliability may be low.

Description of a minimally invasive technique with a modified instrument for the osteosynthesis of proximal femoral fractures using the standard DHS and case series.

INTRODUCTION: the number of hip fractures is estimated to increase from 1.66 million in 1990 to 6.26 million by 2050. Internal fixation is the most common surgical treatment for intertrochanteric fractures. OBJECTIVES: the objective of the present research is to describe a minimally invasive technique with a modified instrument for the treatment of stable proximal femoral trochanteric fractures using the standard DHS, classified as Tronzo types 1 and 2 (AO 31A1.2), and presenting a case series. METHODS: a case was selected to present the technique. Patients operated by this technique undergo a clinical evaluation and preoperative preparation as routine. The criteria for inclusion in the study were the presence of stable fracture of the proximal femur verified by two hip specialist orthopedists, and operated by the minimally invasive technique with a modified instrument using a standard DHS. Exclusion criteria were cases of patients operated for unstable fractures, and the use of other surgical techniques. A case series of 98 patients was performed and discussed. RESULTS: minimally invasive technique with a modified instrument using the standard DHS device can reduce bleeding, it decreases soft tissue injuries, surgical time, and hospital stay, as any other MIPO procedures. Ninety-eight patients underwent the operation (Tronzo types I and II), 59 female and 39 male, ages from 50 to 85 years old. Immediate post-operative complications were shortening of the lower limb, loss of fracture reduction, and death by clinical complications. CONCLUSION: the present study describes a minimally invasive surgical technique using a modified instrument to perform proximal femoral osteosynthesis for stable trochanteric fractures, using the standard DHS.

Description of a minimally invasive technique with a modified instrument for the osteosynthesis of proximal femoral fractures using the standard DHS and case series / Osteossíntese de fraturas do fêmur proximal minimamente invasiva com um instrumento modificado usando o DHS padrão: descrição de técnica e série de casos

ABSTRACT Introduction: the number of hip fractures is estimated to increase from 1.66 million in 1990 to 6.26 million by 2050. Internal fixation is the most common surgical treatment for intertrochanteric fractures. Objectives: the objective of the present research is to describe a minimally invasive technique with a modified instrument for the treatment of stable proximal femoral trochanteric fractures using the standard DHS, classified as Tronzo types 1 and 2 (AO 31A1.2), and presenting a case series. Methods: a case was selected to present the technique. Patients operated by this technique undergo a clinical evaluation and preoperative preparation as routine. The criteria for inclusion in the study were the presence of stable fracture of the proximal femur verified by two hip specialist orthopedists, and operated by the minimally invasive technique with a modified instrument using a standard DHS. Exclusion criteria were cases of patients operated for unstable fractures, and the use of other surgical techniques. A case series of 98 patients was performed and discussed. Results: minimally invasive technique with a modified instrument using the standard DHS device can reduce bleeding, it decreases soft tissue injuries, surgical time, and hospital stay, as any other MIPO procedures. Ninety-eight patients underwent the operation (Tronzo types I and II), 59 female and 39 male, ages from 50 to 85 years old. Immediate post-operative complications were shortening of the lower limb, loss of fracture reduction, and death by clinical complications. Conclusion: the present study describes a minimally invasive surgical technique using a modified instrument to perform proximal femoral osteosynthesis for stable trochanteric fractures, using the standard DHS.

RESUMO Introdução: estima-se que o número de fraturas de quadril aumente de 1,66 milhão em 1990 para 6,26 milhões em 2050. A fixação interna é o tratamento cirúrgico mais comumente utilizado para as fraturas intertrocantéricas. Objetivos: o objetivo da presente investigação é descrever uma técnica minimamente invasiva com um instrumento modificado para o tratamento de fraturas trocantéricas femorais proximais estáveis, classificadas como tipos I e II de Tronzo (AO 31A1.2), usando o DHS padrão, e apresentar uma série de casos. Métodos: foi selecionado um caso aleatório para apresentar a técnica. Os pacientes operados por essa técnica passam por avaliação clínica e preparo pré-operatório de rotina. Os critérios para inclusão no estudo foram a presença de fratura estável do fêmur proximal, verificada por dois ortopedistas especialistas em quadril, e operada pela técnica minimamente invasiva com um instrumento modificado usando um DHS padrão. Os critérios de exclusão foram os casos de pacientes operados por fraturas instáveis e o uso de outras técnicas cirúrgicas. Uma série de casos de 98 pacientes foi realizada e é discutida. Resultados: a técnica minimamente invasiva com o instrumento modificado usando o dispositivo DHS padrão pode reduzir a hemorragia, as lesões dos tecidos moles, o tempo cirúrgico e a estadia hospitalar, tal como quaisquer outros procedimentos de osteossíntese minimamente invasivos. Noventa e oito pacientes foram operados (tipos I e II de Tronzo), 59 do sexo feminino e 39 do masculino, com idades entre 50 e 85 anos. As complicações pós-operatórias imediatas foram encurtamento do membro inferior, perda da redução da fratura e morte por complicações clínicas. Conclusão: o presente estudo descreve uma técnica cirúrgica minimamente invasiva, utilizando um instrumento modificado para realizar osteossíntese femoral proximal para fraturas trocantéricas estáveis, utilizando o DHS padrão.

Biomechanical Evaluation of Different Tibial Fixation Methods in the Reconstruction of the Anterolateral Ligament in Swine Bones.

Objective The present study aims to evaluate different methods of tibial fixation in the reconstruction of the anterolateral ligament (ALL). In addition, the present paper aims to compare the effectiveness of these methods and their mechanisms of failure in swine knees. Methods A total of 40 freshly frozen swine limbs were divided into 4 groups of 10 specimens, according to the tibial fixation technique used. In group A, the tibial fixation of the tendon graft was made through an anchor passing the graft. In group B, the tibial fixation was performed through a metal interference screw in a single bone tunnel. In group C, the tibial fixation included an anchor associated with a tendinous suture (but not with a wire crossing the tendon). In group D, two confluent bony tunnels were drilled and combined with an interference screw in one of them. Results The lowest mean force (70.56 N) was observed in group A, and the highest mean force (244.85 N) was observed in group B; the mean values in the other 2 groups ranged from 171.68 N (group C) to 149.43 N (group D). Considering the margin of error (5%), there was a significant difference between the groups ( p < 0.001). Conclusion Fixation with an interference screw in a single tunnel bone showed the highest tensile strength among the evaluated techniques.