[Translated article] Mechanical resistance of polylactic acid bone matrices developed by 3D printing for the reconstruction of bone defects.

INTRODUCTION: Bone defects are one of the main limitations in orthopaedic surgery and traumatology. For this reason, multiple bone replacement systems have been developed, either by prosthetic implant or by substitution with osteoforming substances, whose limitations are their survival and lack of structurality, respectively. The objective of this work is the generation of a new material for the creation of biologically active structures that have sufficient tensile strength to maintain the structure during remodelling. MATERIAL AND METHODS: A new filament based on the fusion of natural polylactide acid (PLA) powder was designed for the generation of pieces by means of fused deposition modelling (FDM) on which to carry out tensile mechanical tests of osteosynthesis material. A total of 13 groups with different cortical thickness, filling and layer height were carried out, with 10 tensile tests in each group, defining the tensile breaking limit for each group. The regression lines for each group and their mechanical resistance to traction on the filament used were determined. RESULTS: The filament ratio per contact surface unit with the osteosynthesis used was the main determinant of the mechanical resistance to traction, either at the expense of the increase in cortical thickness or by the increase in the percentage of cancellous bone filling. Layer height had a minor effect on tensile strength. The regression value was high for cortical thickness and cancellous filling, being elements with a predictable biomechanical behaviour. CONCLUSIONS: The new methodology allows the creation of personalised neutral and implantable PLA bone matrices for the reconstruction of large bone defects by means of 3D printing by FDM with a mechanical resistance to traction greater than that of current biological support structures.

Mechanical resistance of polylactic acid bone matrices developed by 3D printing for the reconstruction of bone defects. / Resistencia mecánica de matrices óseas de ácido poliláctico desarrolladas por impresión 3D para la reconstrucción de defectos óseos.

INTRODUCTION: Bone defects are one of the main limitations in orthopedic surgery and traumatology. For this reason, multiple bone replacement systems have been developed, either by prosthetic implant or by substitution with osteoforming substances, whose limitations are their survival and lack of structurality, respectively. The objective of this work is the generation of a new material for the creation of biologically active structures that have sufficient tensile strength to maintain the structure during remodeling. MATERIAL AND METHODS: A new filament based on the fusion of natural polylactide acid (PLA) powder was designed for the generation of pieces by means of fused deposition modeling (FDM) on which to carry out tensile mechanical tests of osteosynthesis material. A total of 13 groups with different cortical thickness, filling and layer height were carried out, with 10 tensile tests in each group, defining the tensile breaking limit for each group. The regression lines for each group and their mechanical resistance to traction on the filament used were determined. RESULTS: The filament ratio per contact surface unit with the osteosynthesis used was the main determinant of the mechanical resistance to traction, either at the expense of the increase in cortical thickness or by the increase in the percentage of cancellous bone filling. Layer height had a minor effect on tensile strength. The regression value was high for cortical thickness and cancellous filling, being elements with a predictable biomechanical behavior. CONCLUSIONS: The new methodology allows the creation of personalized neutral and implantable PLA bone matrices for the reconstruction of large bone defects by means of 3D printing by FDM with a mechanical resistance to traction greater than that of current biological support structures.

Estrategias de ahorro de sangre en artroplastía total de rodilla primaria / Blood-saving strategies in total primary knee replacement

Resumen: Introducción: El objetivo del presente estudio fue realizar una actualización sobre las diferentes estrategias en el ahorro de sangre en cirugía protésica de rodilla primaria, a través de una revisión bibliográfica; así como conocer qué estrategias se siguen en diferentes centros hospitalarios de nuestro ámbito, mediante un estudio multicéntrico. Material y métodos: Se realizó un estudio observacional, transversal, descriptivo, basado en una encuesta hecha a 64 cirujanos y una búsqueda bibliográfica sobre los distintos aspectos incluidos en la encuesta. Resultados: Los cirujanos refieren que cuentan con protocolos de ahorro sanguíneo prequirúrgicos implantados en su hospital en 48.4% (31/64). La utilización del ácido tranexámico (ATX) es bastante generalizada en 71.9% de los encuestados (46/64). Éste se administra vía endovenosa previa a la cirugía en 26.6% (17/64) de los casos, de manera intraarticular en 21.9% (14/64) y en una combinación de ambas en 23.4% (15/64). El momento preferido para la colocación de la isquemia por los cirujanos es en 57.8% (37/64) previo a preparar el campo, mientras que 39.1% (25/64) prefiere colocarla en estéril. En 3.1% (2/64) de cirujanos afirma implantar las prótesis sin utilizar isquemia en la cirugía. Discusión: Se está imponiendo la aplicación de ATX como principal estrategia de ahorro de sangre en la artroplastía total de rodilla (ATR). No existe consenso en cuanto a la dosis óptima ni a su vía de administración. La eficacia del ATX está influyendo en la eliminación de los drenajes postquirúrgicos y en la implementación de programas de rehabilitación precoz.

Abstract: Introduction: The objective of this study was to make an update on the different strategies in the blood saving in prosthetic primary knee surgery, through a bibliographical review; As well as to know what strategies are followed in different hospitals in our field, through a survey. Material and methods: We carried out a descriptive transversal observational study based on a survey of 64 surgeons and a bibliographical research on the different aspects included in the survey. Results: Surgeons refer that they have presurgical blood-saving protocols implanted in their Hospital at 48.4%. The use of tranexamic acid (ATX) is quite widespread 71.9% of respondents (46/64). It is administered intravenously prior to surgery in 26.6% of cases, intraarticularly by 21.9% and in a combination of both in 23.4%. The preferred time for the placement of ischemia by surgeons is 57.8% prior to painting the field, while a 39.1% prefer to place it in sterile conditions. 3.1% of surgeons claim to implant the prosthesis without using ischemia in surgery. Discussion: The use of ATX as the primary blood-saving strategy in TKR is being imposed. There is No consensus as to the optimal dose or its route of administration. The efficacy of the ATX is influencing the elimination of post-surgical drainage and the implementation of early rehabilitation programs.

[Blood-saving strategies in total primary knee replacement]. / Estrategias de ahorro de sangre en artroplastía total de rodilla primaria.

INTRODUCTION: The objective of this study was to make an update on the different strategies in the blood saving in prosthetic primary knee surgery, through a bibliographical review; As well as to know what strategies are followed in different hospitals in our field, through a survey. MATERIAL AND METHODS: We carried out a descriptive transversal observational study based on a survey of 64 surgeons and a bibliographical research on the different aspects included in the survey. RESULTS: Surgeons refer that they have presurgical blood-saving protocols implanted in their Hospital at 48.4%. The use of tranexamic acid (ATX) is quite widespread 71.9% of respondents (46/64). It is administered intravenously prior to surgery in 26.6% of cases, intraarticularly by 21.9% and in a combination of both in 23.4%. The preferred time for the placement of ischemia by surgeons is 57.8% prior to painting the field, while a 39.1% prefer to place it in sterile conditions. 3.1% of surgeons claim to implant the prosthesis without using ischemia in surgery. DISCUSSION: The use of ATX as the primary blood-saving strategy in TKR is being imposed. There is No consensus as to the optimal dose or its route of administration. The efficacy of the ATX is influencing the elimination of post-surgical drainage and the implementation of early rehabilitation programs.

INTRODUCCIÓN: El objetivo del presente estudio fue realizar una actualización sobre las diferentes estrategias en el ahorro de sangre en cirugía protésica de rodilla primaria, a través de una revisión bibliográfica; así como conocer qué estrategias se siguen en diferentes centros hospitalarios de nuestro ámbito, mediante un estudio multicéntrico. MATERIAL Y MÉTODOS: Se realizó un estudio observacional, transversal, descriptivo, basado en una encuesta hecha a 64 cirujanos y una búsqueda bibliográfica sobre los distintos aspectos incluidos en la encuesta. RESULTADOS: Los cirujanos refieren que cuentan con protocolos de ahorro sanguíneo prequirúrgicos implantados en su hospital en 48.4% (31/64). La utilización del ácido tranexámico (ATX) es bastante generalizada en 71.9% de los encuestados (46/64). Éste se administra vía endovenosa previa a la cirugía en 26.6% (17/64) de los casos, de manera intraarticular en 21.9% (14/64) y en una combinación de ambas en 23.4% (15/64). El momento preferido para la colocación de la isquemia por los cirujanos es en 57.8% (37/64) previo a preparar el campo, mientras que 39.1% (25/64) prefiere colocarla en estéril. En 3.1% (2/64) de cirujanos afirma implantar las prótesis sin utilizar isquemia en la cirugía. DISCUSIÓN: Se está imponiendo la aplicación de ATX como principal estrategia de ahorro de sangre en la artroplastía total de rodilla (ATR). No existe consenso en cuanto a la dosis óptima ni a su vía de administración. La eficacia del ATX está influyendo en la eliminación de los drenajes postquirúrgicos y en la implementación de programas de rehabilitación precoz.

Tratamiento de las fracturas abiertas de la diáfisis tibial mediante enclavado endomedular fresado / Treatment of open tibial shaft fractures by reamed intramedullary nailing

Para valorar la eficacia y seguridad del enclavado endomedular fresado se hace un estudio retrospectivo de 74 casos de fracturas abiertas de la diáfisis de tibia tratados mediante esta técnica con un seguimiento mínimo de 1 año. Basados en la clasificación de Gustilo, 45 casos eran Grado I, 25 Grado II y cuatro Grado IIIA.La demora media en el enclavado fue de 9 días. Todas las fracturas consolidaron en un tiempo medio de 4 meses.En ningún caso se realizó aporte de injerto óseo. Las complicaciones encontradas fueron infección en el 4 por ciento, dismetría mayor de 1 cm en un caso, rotura de un tornillo en un caso y angulación entre 5 y 10° de valgo en 13 casos. Los resultados sugieren que el enclavado endomedular fresado es una opción segura y eficaz para el tratamiento de las fracturas abiertas de la diáfisis tibial Grados I, II y IIIA (AU)