Experimental and numerical analysis of the influence of intramedullary nail position on the cut-out phenomenon.

BACKGROUND AND OBJECTIVE: Proximal femur fractures, colloquially known as hip fractures, are a common pathology with increasing incidence in the last years due to the enhanced ageing population. Regarding the extracapsular fracture, the treatment for this pathology consists of a fixation of the fragments using an osteosynthesis device, mainly the intramedullary nail. This repairing method implies several complications, which may include the failure of the fixation device, frequently occurring due to the "cut-out" mechanism. The present work focuses on the study of how the position of the cephalic screw, which should be fixed during surgery, affects the cut-out risk. Through experimental tests and numerical models some variables that can be critical for the cut-out phenomenon are analysed. METHODS: This study has been carried out through a numerical model based on the finite element method and experimental tests. The digital image correlation technique has been used in experimental tests to measure displacements on the femoral surface with the objective of numerical model validation. Some basic daily activities with different intramedullary nail positions have been analysed through the numerical model, considering variables that can induce the cut-out complication. RESULTS: The results show how the intramedullary nail position clearly influences the cut-out risk, showing that displacements in the upper, anterior and posterior direction increase the cut-out risk, while displacement in the lower direction endangers the intramedullary nail itself. Thus, the centred position is the one which reduces the cut-out risk. CONCLUSIONS: This work supposes an improvement in the knowledge of the cut-out phenomenon thanks to the combination of experimental testing and validated numerical models. The effects of different intramedullary nail positions in the femoral head are studied, including a novelty variable as torque, which is critical for the structural integrity of the fixation. The main conclusion of the work is the determination of the central intramedullary nail position as the most favourable one for decreasing the cut-out risk.

Tendencias temporales pasadas y proyectadas en la cirugía artroscópica de cadera en España entre 1998 y 2018 / Past and projected temporal trends in arthroscopic hip surgery in Spain between 1998 and 2018

Objetivo: Describir la incidencia poblacional de la artroscopia de cadera desde 1998 hasta 2018 y proyectar las tendencias para el año 2030, así como describir las variaciones en la incidencia poblacional entre las comunidades autónomas (CC. AA.). Material y método: Se realizó una revisión retrospectiva del conjunto mínimo básico de datos de 1998-2018. Se analizó su evolución temporal y se identificaron las variables asociadas con la indicación (edad, sexo, CC. AA.). Por cada comunidad autónoma se calculó la tasa cruda por 100.000 habitantes. Se realizó la proyección 2019-2030 para España mediante regresión lineal. Resultados: En España entre 1998 y 2018 se realizaron un total de 10.663 CAC. La incidencia poblacional en 1998 era de 0,14 CAC por cada 100.000 habitantes, mientras que para el 2018 era de 4,09. Con respecto a 2018, para el año 2030 se espera un incremento de 156,9% en el número de CAC (p<0,001). En promedio las CAC en hombres representaron el 57,7% (IC 95%: 55,2-60,2) de todos los procedimientos y la mayor incidencia se encontró en edades≤44 años. La variación geográfica es del 81%, siendo la diferencia de incidencia por 100.000 habitantes de hasta 15,4 veces entre algunas CC. AA. Conclusiones: El número de artroscopias de cadera en España ha ido en aumento en el periodo 1998-2018, y se prevé que esta tendencia creciente continúe hasta el año 2030. En España los procedimientos artroscópicos de cadera se realizan con más frecuencia en pacientes hombres y en menores de 45 años. La variabilidad de la incidencia poblacional entre las CC. AA. es alta.(AU)

Objective: Describe the population incidence of hip arthroscopy from 1998 to 2018 and to project the trends for the year 2030, as well as to describe the variations in the population incidence between the autonomous communities. Material and method: A retrospective review of the minimum basic data set from 1998 to 2018 was carried out. Temporal evolution was analyzed and the variables associated with the indication (age, sex, regions) were identified. For each region, the crude rate per 100,000 inhabitants was calculated. The 2019–2030 projection was made using linear regression. Results: In Spain between 1998 and 2018 a total of 10,663 arthroscopic hip surgeries were carried out. The population incidence in 1998 was 0.14 CAC per 100,000 inhabitants, while in 2018 it was 4.09. For the year 2030 an increase of 156.9% in the number of arthroscopic hip surgeries is expected (P<.001). On average, 57.7% of all procedures (95% CI 55.2–60.2) were done in men and the highest incidence was found in ages ≤44 years. The geographical variation was 81%, being up to 15.4 times the difference in incidence per 100,000 inhabitants between some regions. Conclusions:The number of hip arthroscopies in Spain has been increasing in the 1998–2018 period and this growing trend is expected to continue until 2030. In Spain, hip arthroscopic procedures are performed more frequently in male patients and in under 45 years old. The variability of the population incidence between the autonomous communities is high.(AU)

[Translated article] Past and projected temporal trends in arthroscopic hip surgery in Spain between 1998 and 2018 / Tendencias temporales pasadas y previstas en la cirugía artroscópica de cadera en España entre 1998 y 2018

Objective: Describe the population incidence of hip arthroscopy from 1998 to 2018 and to project the trends for the year 2030, as well as to describe the variations in the population incidence between the autonomous communities. Material and method: A retrospective review of the minimum basic data set from 1998 to 2018 was carried out. Temporal evolution was analyzed and the variables associated with the indication (age, sex, regions) were identified. For each region, the crude rate per 100,000 inhabitants was calculated. The 2019–2030 projection was made using linear regression. Results: In Spain between 1998 and 2018 a total of 10,663 arthroscopic hip surgeries were carried out. The population incidence in 1998 was 0.14 CAC per 100,000 inhabitants, while in 2018 it was 4.09. For the year 2030 an increase of 156.9% in the number of arthroscopic hip surgeries is expected (P<.001). On average, 57.7% of all procedures (95% CI 55.2–60.2) were done in men and the highest incidence was found in ages ≤44 years. The geographical variation was 81%, being up to 15.4 times the difference in incidence per 100,000 inhabitants between some regions. Conclusions:The number of hip arthroscopies in Spain has been increasing in the 1998–2018 period and this growing trend is expected to continue until 2030. In Spain, hip arthroscopic procedures are performed more frequently in male patients and in under 45 years old. The variability of the population incidence between the autonomous communities is high.(AU)

Objetivo: Describir la incidencia poblacional de la artroscopia de cadera desde 1998 hasta 2018 y proyectar las tendencias para el año 2030, así como describir las variaciones en la incidencia poblacional entre las comunidades autónomas (CC. AA.). Material y método: Se realizó una revisión retrospectiva del conjunto mínimo básico de datos de 1998-2018. Se analizó su evolución temporal y se identificaron las variables asociadas con la indicación (edad, sexo, CC. AA.). Por cada comunidad autónoma se calculó la tasa cruda por 100.000 habitantes. Se realizó la proyección 2019-2030 para España mediante regresión lineal. Resultados: En España entre 1998 y 2018 se realizaron un total de 10.663 CAC. La incidencia poblacional en 1998 era de 0,14 CAC por cada 100.000 habitantes, mientras que para el 2018 era de 4,09. Con respecto a 2018, para el año 2030 se espera un incremento de 156,9% en el número de CAC (p<0,001). En promedio las CAC en hombres representaron el 57,7% (IC 95%: 55,2-60,2) de todos los procedimientos y la mayor incidencia se encontró en edades≤44 años. La variación geográfica es del 81%, siendo la diferencia de incidencia por 100.000 habitantes de hasta 15,4 veces entre algunas CC. AA. Conclusiones: El número de artroscopias de cadera en España ha ido en aumento en el periodo 1998-2018, y se prevé que esta tendencia creciente continúe hasta el año 2030. En España los procedimientos artroscópicos de cadera se realizan con más frecuencia en pacientes hombres y en menores de 45 años. La variabilidad de la incidencia poblacional entre las CC. AA. es alta.(AU)

[Translated article] Past and projected temporal trends in arthroscopic hip surgery in Spain between 1998 and 2018.

OBJECTIVE: Describe the population incidence of hip arthroscopy from 1998 to 2018 and to project the trends for the year 2030, as well as to describe the variations in the population incidence between the autonomous communities. MATERIAL AND METHOD: A retrospective review of the minimum basic data set from 1998 to 2018 was carried out. Temporal evolution was analysed and the variables associated with the indication (age, sex, regions) were identified. For each region, the crude rate per 100,000 inhabitants was calculated. The 2019-2030 projection was made using linear regression. RESULTS: In Spain between 1998 and 2018 a total of 10,663 arthroscopic hip surgeries were carried out. The population incidence in 1998 was 0.14 CAC per 100,000 inhabitants, while in 2018 it was 4.09. For the year 2030 an increase of 156.9% in the number of arthroscopic hip surgeries is expected (p<.001). On average, 57.7% of all procedures (95% CI 55.2-60.2) were done in men and the highest incidence was found in ages≤44 years. The geographical variation was 81%, being up to 15.4 times the difference in incidence per 100,000 inhabitants between some regions. CONCLUSIONS: The number of hip arthroscopies in Spain has been increasing in the 1998-2018 period and this growing trend is expected to continue until 2030. In Spain, hip arthroscopic procedures are performed more frequently in male patients and in under 45 years old. The variability of the population incidence between the autonomous communities is high.

Past and projected temporal trends in arthroscopic hip surgery in Spain between 1998 and 2018. / Tendencias temporales pasadas y proyectadas en la cirugía artroscópica de cadera en España entre 1998 y 2018.

OBJECTIVE: Describe the population incidence of hip arthroscopy from 1998 to 2018 and to project the trends for the year 2030, as well as to describe the variations in the population incidence between the autonomous communities. MATERIAL AND METHOD: A retrospective review of the minimum basic data set from 1998 to 2018 was carried out. Temporal evolution was analyzed and the variables associated with the indication (age, sex, regions) were identified. For each region, the crude rate per 100,000 inhabitants was calculated. The 2019-2030 projection was made using linear regression. RESULTS: In Spain between 1998 and 2018 a total of 10,663 arthroscopic hip surgeries were carried out. The population incidence in 1998 was 0.14 CAC per 100,000 inhabitants, while in 2018 it was 4.09. For the year 2030 an increase of 156.9% in the number of arthroscopic hip surgeries is expected (P<.001). On average, 57.7% of all procedures (95% CI 55.2-60.2) were done in men and the highest incidence was found in ages ≤44 years. The geographical variation was 81%, being up to 15.4 times the difference in incidence per 100,000 inhabitants between some regions. CONCLUSIONS: The number of hip arthroscopies in Spain has been increasing in the 1998-2018 period and this growing trend is expected to continue until 2030. In Spain, hip arthroscopic procedures are performed more frequently in male patients and in under 45 years old. The variability of the population incidence between the autonomous communities is high.

El fenómeno de cut-out en fractura intertrocantérica de fémur: análisis mediante modelo de elementos finitos / The cut-out phenomenon in intertrochanteric femur fracture: analysis using a finite element model

Objetivo: El objetivo del trabajo fue analizar el fenómeno de cut-out, fenómeno que supone desplazamientos oblicuos y/o rotaciones de la cabeza femoral alrededor del componente cefálico del clavo intramedular. El análisis se llevó a cabo mediante modelos numéricos de elementos finitos. Con esta técnica se busca entender el fallo de este tipo de fijaciones y establecer qué posicionamiento del sistema favorece o evita el fallo por cut-out. Material y métodos: El estudio se realizó sobre un modelo numérico de la extremidad proximal de un fémur artificial y un clavo intramedular tipo PFNA (femoral proximal de antirrotación). En el modelo numérico se varió la posición del clavo intramedular en dirección anterior/posterior y superior/inferior para analizar la influencia de la posición en el fenómeno de cut-out. Se analizaron las tensiones en zonas críticas y par torsor sobre el clavo bajo una carga en posición normal. Resultados: La posición más crítica fue aquella en la que el clavo intramedular está colocado en la posición superior, debido a las altas compresiones que aparecen en el hueso trabecular de la cabeza femoral. La posición centrada del clavo disminuyó el riesgo de daño óseo y el par torsor que tiene que soportar el clavo intramedular. Conclusión: Este tipo de modelos permite simular la influencia de la posición del clavo y obtener variables que de otra manera son difíciles de analizar. Aunque se trata de un modelo sencillo con carga estática, confirma que una posición centrada del clavo intramedular disminuye el riesgo de cut-out. (AU)

Objetive: This work aimed to analyze the cut-out phenomenon, which involves oblique displacements and/or rotations of the femoral head around the cephalic component of the intramedullary nail. The analysis was carried out using finite element numerical models. This technique seeks to understand the failure of this type of fixation and establish what positioning of the system favors or prevents failure due to cut-out. Material and methods: The study was carried out on a numerical model of the proximal limb of an artificial femur and an intramedullary nail type PFNA (proximal femoral nail anti-rotation). In the numerical model, the position of the intramedullary nail was varied in the anterior/posterior and superior/inferior directions to analyze the influence of the position on the cut-out phenomenon. Stresses in critical areas and torque on the nail under normal position loading were analyzed. Results: The most critical position was the one in which the intramedullary nail is placed in the superior position, due to the high compressions that appear in the trabecular bone of the femoral head. The centered position of the nail decreased the risk of bone damage and the torque that the intramedullary nail has to support. Conclusion: This type of model allows us to simulate the influence of the nail position and obtain variables that are otherwise difficult to analyze. Although it is a simple model with static load, it confirms that a centered position of the intramedullary nail reduces the risk of cut-out. (AU)

Importance of the gender and preoperative knee sagittal alignment to avoid unnecessary tibial resection in TKR.

BACKGROUND: Standard resections according to the TKR manufacturers can lead to unnecessary bone resections in some patients. The objective of this study was to determine in which patients is recommended to perform a minimal tibial resection (MTR) that could restore the joint line height (JLH). METHODS: Navigation records of 108 consecutive posterior cruciate-substituting TKR performed by one surgeon were analyzed. Optimal tibial resection depth to restore the JLH (0 mm) was calculated by an algorithm. Postoperatively, the knees were distributed in two groups: those in which a MTR (depth ≤ 8 mm) would have been enough to restore the JLH and those in which a standard resection depth would have been necessary. ROC curves and Youden index were used to determine the cutoff point of the coronal and sagittal mechanical axis that predicted a MTR restoring the JLH. Multivariate analysis was used to identify independent factors associated with requiring an MTR. RESULTS: A MTR could be required in 20 (18.5%) knees. In the ROC curve analyses, the cutoff points that best discriminated between minimal and standard tibial resection was ≤ 3° of varus and < 2° of flexion preoperative deformity. Multivariate analysis showed that female gender and preoperative flexion < 2° were significant predictors of requiring a MTR to restore JLH. CONCLUSION: A MTR with the JLH restoration could be possible in female patients with a preoperative sagittal deformity less than 2° of flexion. Preoperative coronal alignment had no influence to discriminate when a MTR is required.

Complications of computer-assisted navigation in total knee replacement: retrospective cohort of eight hundred and seventy eight consecutive knees.

PURPOSE: The main objective was to analyze the computer-assisted navigation (CAN)-specific complications that forced to switch to conventional procedure in primary total knee replacement (TKR). The secondary objective was to determine the influence of those complications on TKR short-term survival. METHODS: Retrospective study of 878 primary TKR in 753 patients. Two consecutive versions of the OrthoPilot navigation system (Braun Aesculap, Germany) were used during the study time. Specific complications of CAN were defined as those due to the instrumentation (hardware or software failures), which were classified in one of two categories according to whether they occurred during the registration or tracking process. RESULTS: There were 20 (2.3%) complications related to the navigation system use that forced to switch to conventional surgery: in 11 (1.2%) knees due to loosening of the tracking pins, and in the other nine (1.0%) there were information system failures. There was a trend for a higher conversion rate to conventional surgery with the use of the first version of the software. There were no fractures, infections, or nerve injuries at the pin site. We found no differences in the distribution of baseline variables among those with or without conversion to conventional surgery. There was no significant difference (p = 0.488) in the two year survival between patients with or without conversion. CONCLUSION: CAN for primary TKR is a safe method with few specific complications that forced to switch from the navigated to the conventional procedure. Conversion to conventional surgery did not affect the short-term survival of TKR.

Validación experimental de un modelo de análisis de elementos finitos en fractura de cadera y su aplicabilidad clínica / Experimental validation of finite elements model in hip fracture and its clinical applicability

La fractura de la extremidad proximal de fémur es objeto de interés en investigación. La complejidad del entramado óseo y la ineficiencia estructural asociada al envejecimiento hacen que existan muchas variables todavía por comprender desde el punto de vista experimental, pero no existe un modelo de investigación estructural y biomecánico de la fractura de cadera claramente definido. La hipótesis de este trabajo es que es posible desarrollar un modelo de experimentación computacional que caracterice el hueso de la extremidad proximal del fémur como un material heterogéneo a partir de la traslación directa de los parámetros mecánicos obtenidos de piezas anatómicas de experimentación. Material y método: Trabajo experimental que compara la experimentación real en cadáver y un modelo numérico basado en análisis de elementos finitos (AEF). Las variables que se han empleado son: punto de inicio de la fractura, su propagación, carga progresiva y la carga máxima hasta fractura. Al modelo computacional se trasladaron los parámetros mecánicos reales obtenidos de las piezas anatómicas basándose en la relación entre las unidades Hounsfield de la TAC de alta resolución y la densidad mineral ósea de cada elemento virtual, mientras que la propagación de la fractura se modeló mediante desarrollo computacional propio del equipo investigador, con disminución de las propiedades mecánicas de los elementos dañados conforme avanza la línea fractuaria. Resultados: El modelo computacional fue capaz de determinar el punto de inicio de la fractura, con una discreta tendencia a la medialización anatómica de dicho punto respecto a lo ocurrido de manera experimental. El grado de correlación fue muy alto al comparar el valor real de deformación progresiva de las muestras frente al obtenido por el modelo computacional. Sobre 32 puntos analizados, se obtuvo una pendiente de 1,03 en regresión lineal, con un error relativo entre las deformaciones del 6% y un coeficiente de Pearson de R2=0,99. El modelo computacional infraestimó discretamente la carga máxima de fractura, con un error relativo aproximado al 10%. Conclusión: El modelo computacional de AEF desarrollado por este equipo investigador multidisciplinar se puede considerar, en conjunto, un modelo completo de AEF de la extremidad proximal del fémur con aplicabilidad clínica futura al ser capaz de simular e imitar el comportamiento biomecánico de fémures humanos contrastado con un modelo experimental clásico realizado en piezas anatómicas. Sobre esta base podrán evaluarse interacciones cualitativas y cuantitativas que lo consoliden como un potente banco de ensayos de experimentación computacional sobre el fémur proximal humano

Fracture of the proximal extremity of the femur is the subject of research interest. The complexity of the bone framework and the structural inefficiency associated with ageing leave many variables yet to be understood from an experimental perspective. However, there is no clearly defined structural and biomechanical research model for hip fracture. The hypothesis of this paper is that it is possible to create a computational experimentation model that characterises the bone of the proximal extremity of the femur as a heterogeneous material from directly translating the mechanical parameters obtained from anatomical experimentation specimens. Material and method: An experimental paper comparing real experimentation on cadavers and a numerical model based on finite element analysis (FEA). The variables uses were: the start point of the fracture, propagation of the fracture, progressive load and maximum load until fracture. The real mechanical parameters obtained from the anatomical specimens were translated to the computational model based on the relationship between the Hounsfield units of the high resolution CAT scan and the bone mineral density of each virtual element, whereas the propagation of the fracture was modelled by the research team's own computational design, reducing the mechanical properties of the damaged elements as the fracture line advanced. Results: The computational model was able to determine the start point of the fracture, with a slight tendency towards anatomical medialisation of this point compared to what happened experimentally. The degree of correlation was very high on comparing the real value of progressive deformation of the samples compared to that obtained by the computational model. Over 32 points analysed, a slope of 1.03 in lineal regression was obtained, with a relative error between the deformations of 16% and a Pearson's coefficient of R2=.99. The computational model slightly underestimated the maximum fracture load, with a relative error of approximately 10%. Conclusion: The FEA computational model developed by this multi-disciplinary research team could be considered, as a whole, a complete FEA model of the proximal extremity of the femur with future clinical applicability since it was able to simulate and imitate the biomechanical behaviour of human femurs contrasted with a traditional experimental model made from anatomical specimens. On this basis, qualitative and quantitative interactions can be assessed which consolidate it as a powerful computational experimentation test bench for the human proximal femur

Efecto de la osteotomía medializante de calcáneo sobre tejidos blandos de soporte del arco plantar: un estudio computacional / Effect of the calcaneal medializing osteotomy on soft tissues supporting the plantar arch: a computational study

La osteotomía medializante de calcáneo forma parte del elenco de opciones de tratamiento en el pie plano adquirido en adultos. La corrección estructural que se consigue es ampliamente conocida. Sin embargo, el efecto de este procedimiento sobre los tejidos blandos que soportan el arco plantar ha sido poco estudiado, pues experimentalmente no es posible cuantificar las variaciones de tensión y deformación generadas. Por lo tanto, el objetivo de este estudio fue evaluar el efecto que tiene la osteotomía medializante de calcáneo sobre el tejido blando que soporta el arco plantar, usando un modelo computacional de pie humano diseñado con un enfoque clínico. El modelo por elementos finitos propuesto fue reconstruido a partir de imágenes de tomografías computarizadas de un paciente sano. Se incluyeron todos los huesos del pie, la fascia plantar, cartílagos, ligamentos plantares y el ligamento calcáneo-navicular, respetando su distribución anatómica y propiedades biomecánicas. Las simulaciones fueron realizadas emulando la fase de apoyo monopodal de la marcha humana de un adulto. El efecto sobre cada tejido fue evaluado siguiendo criterios clínicos y biomecánicos. Los resultados muestran que la osteotomía de calcáneo reduce la tensión generada normalmente sobre los tejidos evaluados, siendo el efecto sobre el ligamento calcáneo-navicular y la fascia plantar los más notables. Los resultados de deformación obtenidos son consistentes con ensayos experimentales y el conocimiento clínico. La versatilidad de este modelo permite la valoración objetiva de diferentes condiciones y apoya la toma de decisión para el tratamiento del pie plano adquirido en adultos en estadios medio y avanzado

Medializing calcaneal osteotomy forms part of the treatment options for adult acquired flat foot. The structural correction that is achieved is widely known. However, the effect of this procedure on the soft tissues that support the plantar arch has been little studied, since it is not possible to quantify experimentally the tension and deformation variations generated. Therefore, the objective of this study was to evaluate the effect of medializing calcaneal osteotomy on the soft tissue that supports the plantar arch, using a computational model of the human foot designed with a clinical approach. The proposed finite element model was reconstructed from computerized tomography images of a healthy patient. All the bones of the foot, the plantar fascia, cartilages, plantar ligaments and the calcaneus-navicular ligament were included, respecting their anatomical distribution and biomechanical properties. Simulations were performed emulating the monopodal support phase of the human walk of an adult. The effect on each tissue was evaluated according to clinical and biomechanical criteria. The results show that calcaneal osteotomy reduces the tension normally generated on the evaluated tissues, with the effect on the calcaneus-navicular ligament and the plantar fascia being the most notable. The deformation results obtained are consistent with experimental tests and clinical knowledge. The versatility of this model allows the objective assessment of different conditions and supports decision making for the treatment of adult acquired flat foot in middle and advanced stages

Spanish National Hip Fracture Registry (RNFC): analysis of its first annual report and international comparison with other established registries.

Hip fracture registries have helped improve quality of care and reduce variability, and several audits exist worldwide. The results of the Spanish National Hip Fracture Registry are presented and compared with 13 other national registries, highlighting similarities and differences to define areas of improvement, particularly surgical delay and early mobilization. INTRODUCTION: Hip fracture audits have been useful for monitoring current practice and defining areas in need of improvement. Most established registries are from Northern Europe. We present the results from the first annual report of the Spanish Hip Fracture Registry (RNFC) and compare them with other publically available audit reports. METHOD: Comparison of the results from Spain with the most recent reports from another ten established hip fracture registries highlights the differences in audit characteristics, casemix, management, and outcomes. RESULTS: Of the patients treated in 54 hospitals, 7.208 were included in the registry between January and October 2017. Compared with other registries, the RNFC included patients ≥ 75 years old; in general, they were older, more likely to be female, had a worse prefracture ambulation status, and were more likely to have extracapsular fractures. A larger proportion was treated with intramedullary nails than in other countries, and spinal anesthesia was most commonly used. With a mean of 75.7 h, Spain had by far the longest surgical delay, and the lowest proportion of patients mobilized on the first postoperative day (58.5%). Consequently, development of pressure ulcers was high, but length of stay, mortality, and discharge to home remained in the range of other audits. CONCLUSIONS: National hip fracture registries have proved effective in changing clinical practice and our understanding of patients with this condition. Such registries tend to be based on an internationally recognized common dataset which would make comparisons between national registries possible, but variations such as age inclusion criteria and follow-up are becoming evident across the world. This variation should be avoided if we are to maximize the comparability of registry results and help different countries learn from each other's practice. The results reported in the Spanish RNFC, compared with those of other countries, highlight the differences between countries and detect areas of improvement, particularly surgical delay and early mobilization.

Effect of the calcaneal medializing osteotomy on soft tissues supporting the plantar arch: A computational study. / Efecto de la osteotomía medializante de calcáneo sobre tejidos blandos de soporte del arco plantar: un estudio computacional.

Medializing calcaneal osteotomy forms part of the treatment options for adult acquired flat foot. The structural correction that is achieved is widely known. However, the effect of this procedure on the soft tissues that support the plantar arch has been little studied, since it is not possible to quantify experimentally the tension and deformation variations generated. Therefore, the objective of this study was to evaluate the effect of medializing calcaneal osteotomy on the soft tissue that supports the plantar arch, using a computational model of the human foot designed with a clinical approach. The proposed finite element model was reconstructed from computerized tomography images of a healthy patient. All the bones of the foot, the plantar fascia, cartilages, plantar ligaments and the calcaneus-navicular ligament were included, respecting their anatomical distribution and biomechanical properties. Simulations were performed emulating the monopodal support phase of the human walk of an adult. The effect on each tissue was evaluated according to clinical and biomechanical criteria. The results show that calcaneal osteotomy reduces the tension normally generated on the evaluated tissues, with the effect on the calcaneus-navicular ligament and the plantar fascia being the most notable. The deformation results obtained are consistent with experimental tests and clinical knowledge. The versatility of this model allows the objective assessment of different conditions and supports decision making for the treatment of adult acquired flat foot in middle and advanced stages.

Experimental validation of finite elements model in hip fracture and its clinical applicability. / Validación experimental de un modelo de análisis de elementos finitos en fractura de cadera y su aplicabilidad clínica.

Fracture of the proximal extremity of the femur is the subject of research interest. The complexity of the bone framework and the structural inefficiency associated with ageing leave many variables yet to be understood from an experimental perspective. However, there is no clearly defined structural and biomechanical research model for hip fracture. The hypothesis of this paper is that it is possible to create a computational experimentation model that characterises the bone of the proximal extremity of the femur as a heterogeneous material from directly translating the mechanical parameters obtained from anatomical experimentation specimens. MATERIAL AND METHOD: An experimental paper comparing real experimentation on cadavers and a numerical model based on finite element analysis (FEA). The variables uses were: the start point of the fracture, propagation of the fracture, progressive load and maximum load until fracture. The real mechanical parameters obtained from the anatomical specimens were translated to the computational model based on the relationship between the Hounsfield units of the high resolution CAT scan and the bone mineral density of each virtual element, whereas the propagation of the fracture was modelled by the research team's own computational design, reducing the mechanical properties of the damaged elements as the fracture line advanced. RESULTS: The computational model was able to determine the start point of the fracture, with a slight tendency towards anatomical medialisation of this point compared to what happened experimentally. The degree of correlation was very high on comparing the real value of progressive deformation of the samples compared to that obtained by the computational model. Over 32 points analysed, a slope of 1.03 in lineal regression was obtained, with a relative error between the deformations of 16% and a Pearson's coefficient of R2=.99. The computational model slightly underestimated the maximum fracture load, with a relative error of approximately 10%. CONCLUSION: The FEA computational model developed by this multi-disciplinary research team could be considered, as a whole, a complete FEA model of the proximal extremity of the femur with future clinical applicability since it was able to simulate and imitate the biomechanical behaviour of human femurs contrasted with a traditional experimental model made from anatomical specimens. On this basis, qualitative and quantitative interactions can be assessed which consolidate it as a powerful computational experimentation test bench for the human proximal femur.

Seguridad de los portales metacarpofalángicos. Estudio anatómico / Metacarpophalangeal portal safety. An anatomical study

Objetivo: Cuantificar el riesgo de lesión de la inervación dorsal al realizar portales directos de la articulación metacarpofalángica del segundo al quinto dedo. Material y método: Se realizó un estudio anatómico de 11 extremidades superiores de cadáveres frescos. Tras colocarlos en torre de tracción, se realizaron los portales metacarpofalángicos a ambos lados del tendón extensor. Se disecaron las ramas sensitivas dorsales y se midieron las distancias entre el portal y el nervio más cercano mediante un calibrador digital. Se compararon de forma global los portales de todos los dedos para valorar el dedo más seguro y se compararon dos a dos los portales radial y ulnar en cada uno de los dedos, para valorar el portal más seguro dentro de cada dedo. Resultados: La comparación global de todos los portales y dedos mostró que el tercer dedo es el más seguro en cualquiera de sus portales, mientras que el lado ulnar del segundo y radial del cuarto son los que tienen riesgo más alto de lesión nerviosa (p=8,96·10-5). La comparación dos a dos de los portales radial y ulnar en cada uno de los dedos mostró que el portal ulnar en más seguro que el radial en el cuarto dedo (p=0,042), mientras que el radial es más seguro que el ulnar en el quinto dedo (p=0,003). Conclusiones: El tercer dedo fue el más seguro para la realización de los portales metacarpofalángicos, mientras que el lado ulnar del segundo dedo y el lado radial del cuarto son los de más alto riesgo de lesión nerviosa

Aim: To quantify the risk of dorsal innervation injury when performing direct metacarpophalangeal joint portals of the second to fifth fingers. Material and method: An anatomical study of 11 upper limbs of fresh corpses was carried out. After placing them in a traction tower, the metacarpophalangeal portals were developed on both sides of the extensor tendon. The dorsal sensory branches were dissected and the distances between the portal and the nearest nerve were measured by a digital caliper. The portals of all the fingers were compared globally to assess the safest finger and two to two radial and ulnar portals were compared in each of the fingers to assess the safest portal within each finger. Results: The overall comparison of all portals and fingers showed that the third finger is the safest in any of its portals, while the ulnar side of the second and radial of the fourth are the portals with the highest risk of nerve injury (P=8.96·10-5). Comparing two to two of the radial and ulnar portals in each of the fingers showed that the ulnar portal is safer than the radial on the fourth finger (P=.042), while the radial is safer than the ulnar on the fifth finger (P=.003). Conclusions: The third finger was the safest to perform metacarpophalangeal portals, while the ulnar side of the second finger and radial side of the fourth had the highest risk of nerve injury

Beyond orthogeriatric co-management model: benefits of implementing a process management system for hip fracture.

Hip fracture is a major health care problem worldwide. Business process management systems (PMSs) have made significant contributions in health care environments to improve patient care standards. The effectiveness of PMS applied to hip fracture in older adults in the acute phase has been demonstrated. INTRODUCTION: Fragility fracture is a major health care problem worldwide. Business PMSs have made significant contributions in health care environments to improve patient care standards. It is a new way of management that defines a homogeneous application procedure involving eliminating steps that add no value and developing explicit supervision criteria, in addition to identifying the appropriate managers. PURPOSE: The aim of our trial was to assess the effectiveness of the PMS applied to hip fracture versus the orthogeriatric co-management model in the acute phase. METHODS: All consecutive patients aged ≥ 65 who were admitted to Hospital Universitario Infanta Leonor between January 1, 2009, and December 31, 2016, for acute hip fracture surgery were included. We compared the effectiveness indicators in the acute phase between the preprocess period (orthogeriatric co-management) and the process period. RESULTS: One thousand two hundred twenty-two patients were included (76.6% women). Mean age (SD) was 83.9 (6.4) years. Effectiveness management indicators are the following: length of hospital stay, time to admission to the ward from the emergency department, preoperative stay, surgery in < 48 h, and the operating room availability which were all improved in the process period with statistical significance. Effectiveness clinical indicators are the following: the numbers of patients with operated limb loading approved after surgery, discharged to home, and with osteoporosis treatment postfracture at the time of discharge which were statistically significantly higher in the process period, and the number of patients who suffered from delirium was statistically significantly lower in the process period. The number of in-hospital deaths was lower during the process period without statistical significance. CONCLUSION: Our results demonstrated the effectiveness of the PMS applied to hip fracture in older adults compared with an orthogeriatric co-management model in the acute phase, based on both management indicators and clinical indicators.

Metacarpophalangeal portal safety. An anatomical study. / Seguridad de los portales metacarpofalángicos. Estudio anatómico.

AIM: To quantify the risk of dorsal innervation injury when performing direct metacarpophalangeal joint portals of the second to fifth fingers. MATERIAL AND METHOD: An anatomical study of 11 upper limbs of fresh corpses was carried out. After placing them in a traction tower, the metacarpophalangeal portals were developed on both sides of the extensor tendon. The dorsal sensory branches were dissected and the distances between the portal and the nearest nerve were measured by a digital caliper. The portals of all the fingers were compared globally to assess the safest finger and two to two radial and ulnar portals were compared in each of the fingers to assess the safest portal within each finger. RESULTS: The overall comparison of all portals and fingers showed that the third finger is the safest in any of its portals, while the ulnar side of the second and radial of the fourth are the portals with the highest risk of nerve injury (P=8.96·10-5). Comparing two to two of the radial and ulnar portals in each of the fingers showed that the ulnar portal is safer than the radial on the fourth finger (P=.042), while the radial is safer than the ulnar on the fifth finger (P=.003). CONCLUSIONS: The third finger was the safest to perform metacarpophalangeal portals, while the ulnar side of the second finger and radial side of the fourth had the highest risk of nerve injury.

Volar Central Portal in Wrist Arthroscopy.

Background Nowadays, the wrist is not limited to a dorsal visualization; the joint can be thought of as a "box," which can be visualized from almost every perspective. The purpose of this study was to describe a new volar central portal for the wrist, following three principles: a single incision that allows access to both the radiocarpal and midcarpal joints, centered on the lunate, with the volar structures at risk protected not only by retractors, but also by tendons. Description of Technique The incision begins in the distal wrist crease and extended 1.5 cm proximally up to the proximal wrist crease, following the axis of the third intermetacarpal space. The flexor superficialis tendons are identified and retracted toward the radial side. Next, the fourth and fifth flexor digitorum profundus tendons are retracted toward the ulnar side, while the third and second tendons are retracted toward the radial side. The volar central midcarpal portal is performed under direct vision just over the anterior horn of the lunate through the Poirier space. The volar central radiocarpal portal is created under the lunate through the interval between the ulnocarpal ligaments and the short radioulnar ligament. Methods An anatomical study was performed on 14 cadaver specimens. Two data were recorded: iatrogenic injuries of the structures at risk and the distances to the structures at risk. Results The median (interquartile range [IQR]) distances from the volar central radiocarpal portal to the median nerve, palmar cutaneous branch of the median nerve, and ulnar neurovascular bundle were 10.5 (7.8-15.0), 18.5 (15.8-20.3), and 7.0 (5.0-10.5) mm, respectively. The median (IQR) distances from the volar central midcarpal portal to the median nerve, palmar cutaneous branch of the median nerve, and ulnar neurovascular bundle were 7.0 (4.8-10.3), 16.0 (14.8-19.0), and 4.5 (3.8-9.0) mm, respectively. No iatrogenic injuries were observed. Conclusion The volar central portal is reproducible and safe. The risk of iatrogenic injury is low. The capsule is pierced through one of its thinner portions, and both the radiocarpal and midcarpal joints can be inspected through one single incision.

Guía SECOT-GEIOS en osteoporosis y fractura por fragilidad. Actualización / SECOT-GEIOS guidelines in osteoporosis and fragility fracture. An update

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