Evolución de los niveles séricos de cromo y cobalto tras el empleo de un vástago con cuello modular en la artroplastia total de cadera primaria / Evolution of chromium and cobalt serum levels after the use of a modular neck stem in primary total hip arthroplasty

Introducción y objetivos: Los vástagos primarios con cuellos modulares fueron introducidos con la ventaja teórica de restaurar la anatomía de la cadera de forma más precisa. Sin embargo, la presencia de un segundo encaje se ha asociado a una mayor corrosión y liberación de detritos metálicos. El objetivo de nuestro estudio es cuantificar los valores séricos de cromo y de cobalto, y analizar su evolución temporal durante cinco años. Material y métodos: Se presenta una serie prospectiva de 61 pacientes intervenidos de artroplastia total de cadera primaria mediante la implantación del vástago HMAX-M® (Limacorporate, San Daniele, Italia) en los que se realizó una determinación sérica de cromo y cobalto a los seis meses, a los dos años y a los cinco años. Resultados: Nuestra serie presenta una elevación progresiva de los niveles de cromo, con una diferencia significativa entre los valores de cromo a los seis meses (0,35±0,18) y los cinco años (0,52±0,36), p=0,01. Respecto al cobalto, se observa una elevación estadísticamente significativa entre los seis meses y los dos años y una posterior estabilización hasta los cinco años, siendo la media de cobalto a los seis meses (1,17±0,8) significativamente menor que a los dos años (2,63±1,76) y a los cinco años (2,84±2,1), p=0,001. Conclusión: Se ha observado una elevación de los niveles séricos de cobalto en aquellos pacientes a los que se les implantó un vástago con cuello modular. Los resultados obtenidos en este estudio han limitado el uso de vástagos con cuello modular en nuestra práctica habitual.(AU)

Introduction and objectives: Modular neck primary stems were introduced with the theoretical advantage of restoring the hip anatomy more precisely. However, the presence of a second junction has been associated with increased corrosion and release of metal debris. The objective of our study is to quantify of chromium and cobalt serum values, and to analyze their temporal evolution during five years. Material and methods: We present a prospective series of 61 patients who underwent primary total hip arthroplasty by implantation of the HMAX-M® stem (Limacorporate, San Daniele, Italy). Serum chromium and cobalt determinations were performed at six months, two years and five years. Results: Our series shows a progressive elevation in chromium levels with a significant difference between chromium values at six months (0.35±0.18) and five years (0.52±0.36), P=.01. Regarding cobalt, a statistically significant elevation is observed between six months and two years and a subsequent stabilization of values between two and five years, with a cobalt mean at six months (1.17±0.8) significantly lower than at two (2.63±1.76) and five years (2.84±2.1), P=.001. Conclusion: Elevated serum cobalt levels have been observed in patients who underwent modular neck stem implantation. The results obtained in this study have limited the use of stems with a modular neck in our clinical practice.(AU)

[Translated article] Evolution of chromium and cobalt serum levels after the use of a modular neck stem in primary total hip arthroplasty / Evolución de los niveles séricos de cromo y cobalto tras el empleo de un vástago con cuello modular en la artroplastia total de cadera primaria

Introducción y objetivos: Los vástagos primarios con cuellos modulares fueron introducidos con la ventaja teórica de restaurar la anatomía de la cadera de forma más precisa. Sin embargo, la presencia de un segundo encaje se ha asociado a una mayor corrosión y liberación de detritos metálicos. El objetivo de nuestro estudio es cuantificar los valores séricos de cromo y de cobalto, y analizar su evolución temporal durante cinco años. Material y métodos: Se presenta una serie prospectiva de 61 pacientes intervenidos de artroplastia total de cadera primaria mediante la implantación del vástago HMAX-M® (Limacorporate, San Daniele, Italia) en los que se realizó una determinación sérica de cromo y cobalto a los seis meses, a los dos años y a los cinco años. Resultados: Nuestra serie presenta una elevación progresiva de los niveles de cromo, con una diferencia significativa entre los valores de cromo a los seis meses (0,35±0,18) y los cinco años (0,52±0,36), p=0,01. Respecto al cobalto, se observa una elevación estadísticamente significativa entre los seis meses y los dos años y una posterior estabilización hasta los cinco años, siendo la media de cobalto a los seis meses (1,17±0,8) significativamente menor que a los dos años (2,63±1,76) y a los cinco años (2,84±2,1), p=0,001. Conclusión: Se ha observado una elevación de los niveles séricos de cobalto en aquellos pacientes a los que se les implantó un vástago con cuello modular. Los resultados obtenidos en este estudio han limitado el uso de vástagos con cuello modular en nuestra práctica habitual.(AU)

Introduction and objectives: Modular neck primary stems were introduced with the theoretical advantage of restoring the hip anatomy more precisely. However, the presence of a second junction has been associated with increased corrosion and release of metal debris. The objective of our study is to quantify of chromium and cobalt serum values, and to analyze their temporal evolution during five years. Material and methods: We present a prospective series of 61 patients who underwent primary total hip arthroplasty by implantation of the HMAX-M® stem (Limacorporate, San Daniele, Italy). Serum chromium and cobalt determinations were performed at six months, two years and five years. Results: Our series shows a progressive elevation in chromium levels with a significant difference between chromium values at six months (0.35±0.18) and five years (0.52±0.36), P=.01. Regarding cobalt, a statistically significant elevation is observed between six months and two years and a subsequent stabilization of values between two and five years, with a cobalt mean at six months (1.17±0.8) significantly lower than at two (2.63±1.76) and five years (2.84±2.1), P=.001. Conclusion: Elevated serum cobalt levels have been observed in patients who underwent modular neck stem implantation. The results obtained in this study have limited the use of stems with a modular neck in our clinical practice.(AU)

Evolution of chromium and cobalt serum levels after the use of a modular neck stem in primary total hip arthroplasty. / Evolución de los niveles séricos de cromo y cobalto tras el empleo de un vástago con cuello modular en la artroplastia total de cadera primaria.

INTRODUCTION AND OBJECTIVES: Modular neck primary stems were introduced with the theoretical advantage of restoring the hip anatomy more precisely. However, the presence of a second junction has been associated with increased corrosion and release of metal debris. The objective of our study is to quantify of chromium and cobalt serum values, and to analyze their temporal evolution during five years. MATERIAL AND METHODS: We present a prospective series of 61 patients who underwent primary total hip arthroplasty by implantation of the HMAX-M® stem (Limacorporate, San Daniele, Italy). Serum chromium and cobalt determinations were performed at six months, two years and five years. RESULTS: Our series shows a progressive elevation in chromium levels with a significant difference between chromium values at six months (0.35±0.18) and five years (0.52±0.36), P=.01. Regarding cobalt, a statistically significant elevation is observed between six months and two years and a subsequent stabilization of values between two and five years, with a cobalt mean at six months (1.17±0.8) significantly lower than at two (2.63±1.76) and five years (2.84±2.1), P=.001. CONCLUSION: Elevated serum cobalt levels have been observed in patients who underwent modular neck stem implantation. The results obtained in this study have limited the use of stems with a modular neck in our clinical practice.

[Translated article] Evolution of chromium and cobalt serum levels after the use of a modular neck stem in primary total hip arthroplasty.

INTRODUCTION AND OBJECTIVES: Modular neck primary stems were introduced with the theoretical advantage of restoring the hip anatomy more precisely. However, the presence of a second junction has been associated with increased corrosion and release of metal debris. The objective of our study is to quantify of chromium and cobalt serum values, and to analyse their temporal evolution during five years. MATERIAL AND METHODS: We present a prospective series of 61 patients who underwent primary total hip arthroplasty by implantation of the H MAX-M® stem (Limacorporate, San Daniele, Italy). Serum chromium and cobalt determinations were performed at six months, two years and five years. RESULTS: Our series shows a progressive elevation in chromium levels with a significant difference between chromium values at six months (0.35±0.18) and five years (0.52±0.36), p=.01. Regarding cobalt, a statistically significant elevation is observed between six months and two years and a subsequent stabilisation of values between two and five years, with a cobalt mean at six months (1.17±0.8) significantly lower than at two (2.63±1.76) and five years (2.84±2.1), p=.001. CONCLUSION: Elevated serum cobalt levels have been observed in patients who underwent modular neck stem implantation. The results obtained in this study have limited the use of stems with a modular neck in our clinical practice.

Altitudinal distribution of the functional feeding groups of aquatic macroinvertebrates using an ecological network in Andean streams / Distribución altitudinal de los grupos funcionales de alimentación de macroinvertebrados acuáticos utilizando una red ecológica en arroyos andinos

Abstract Introduction: Analysis of functional feeding groups (FFG) in aquatic macroinvertebrates is important in understanding the structure, function, and dynamics of ecological processes in ecosystems. Modularity refers to the degree of compartmentalization of food webs and varies between -1 and 1. A network with a modularity value close to 1 is resilient to disturbances and can be interpreted as an indicating factor for the stability of communities. Objective: In this study, we analyzed the trophic structure of benthic macroinvertebrates in La Nitrera stream, the San Juan River, and the Cauca River in the Colombian Andes. Methods: The study was supported by ecological networking techniques using Gephi software. We studied nine sites in dry, rainy, and transition seasons in 2017 and 2018, monitoring changes in the altitude gradient. At each of the sites, the organisms were captured and determined, and physicochemical and hydraulic information was obtained. Results: The variance component analysis allowed to explain the variability of the data by relating the following environmental variables: FFG, diversity, richness, modularity, season, and time. Simple multifactorial ANOVA indicated that significant changes in FFG were associated with altitude, and modularity to time. The allocation of the FFG was done by stomach analysis and secondary information. Conclusion: The transition season had the highest modularity, possibly due to the recolonization of some biotopes caused by the decrease in the velocity of water currents. La Nitrera and San Juan presented higher values than the Cauca, which may indicate that the altitudinal change and velocity of water currents affects the compartmentalization of the network.

Resumen Introducción: El análisis de grupos funcionales de alimentación (GFA) en macroinvertebrados acuáticos es importante para comprender la estructura, función y dinámica de los ecosistemas de procesos ecológicos. La modularidad se refiere al grado de compartimentación de las redes alimentarias y varía entre -1 y 1. Una red con un valor de modularidad cercano a 1 es resistente a las alteraciones y puede interpretarse como un factor indicativo para la estabilidad de las comunidades. Objetivo: En este estudio se analizó la estructura trófica de los macroinvertebrados bentónicos, un elemento importante en la calidad ambiental, en el arroyo La Nitrera, el río San Juan y el río Cauca. Métodos: El estudio contó con el apoyo de técnicas de redes ecológicas utilizando el software Gephi. En 2017 y 2018, estudiamos nueve sitios en estaciones secas, lluviosas y de transición, monitoreando cambios en el gradiente de altitud. En cada uno de los sitios se capturaron y determinaron los organismos y se recogió información fisicoquímica e hidráulica. Resultados: El análisis de componentes de varianza permitió explicar la variabilidad de los datos relacionando las siguientes variables ambientales: GFA, diversidad, riqueza, modularidad, estación y tiempo. La ANOVA simple multifactorial indicó que existen cambios significativos en los GFA en relación con la altitud, y la modularidad con el tiempo. La asignación de los GFA se realizó mediante análisis estomacal e información secundaria. Conclusión: La temporada de transición tuvo la mayor modularidad, posiblemente debido a la recolonización de algunos biotopos provocada por la disminución de la velocidad del cauce. La Nitrera y San Juan presentaron valores superiores a los del Cauca, lo que puede indicar que el cambio altitudinal y la velocidad de las corrientes de agua influyen en la compartimentación de la red.

Comparación de la corrección de la discrepancia de longitud de miembros tras el empleo de un vástago con cuello modular y su homólogo monobloque en la artroplastia total de cadera primaria / Comparison of leg length discrepancy correction after the use of a modular neck stem and its monoblock homologue in total primary hip arthroplasty

Introducción y objetivos: Los vástagos con doble modularidad buscan restaurar de forma más precisa la anatomía al permitir ajustes intraoperatorios gracias a los cuellos modulares. Nuestro objetivo es comparar la corrección radiográfica de la longitud con el vástago H MAX-M® frente a su homólogo monobloque H MAX-S®. Material y métodos: Se realizó un estudio de cohortes prospectivo mediante muestreo consecutivo sobre pacientes intervenidos de artroplastia total de cadera primaria con el diagnóstico de coxartrosis entre el año 2011 y 2015. Un brazo de la cohorte incluyó a los pacientes intervenidos con vástago modular y el otro con vástago monobloque. Se midió la longitud en la radiografía anteroposterior de pelvis en carga a los seis meses. Las medias de las mediciones obtenidas para cada brazo de la cohorte se compararon entre sí. Resultados: No se han observado diferencias estadísticamente significativas en la corrección de la disimetría entre ambos grupos determinada como la diferencia de longitud entre la cadera operada y la cadera contralateral (p=0,106). Tampoco se observaron diferencias en los valores postoperatorios de longitud (p=0,053). Cabe decir que tanto para el vástago modular como para el vástago monobloque el grupo mayoritario es aquel con longitud restaurada (84,1 y 80,4%, respectivamente; p=0,001). Conclusión: A pesar de la ventaja teórica de la modularidad y que disponer de piezas intercambiables podría ser de gran interés, en nuestro estudio no hemos podido demostrar que exista una superioridad de los diseños modulares frente al monoblock para control de la disimetría postoperatoria.(AU)

Introduction and objective: Dual modularity stems seek to more precisely restore anatomy by allowing intraoperative adjustments thanks to modular necks. Our aim is to compare the radiographic length correction with the H MAX-M® Stem versus its monoblock counterpart H MAX-S®. Material and methods: A prospective cohort study was carried out through consecutive sampling on patients who underwent primary total hip arthroplasty with coxarthrosis diagnosis between 2011 and 2015. One arm of the cohort included patients who were operated with a modular stem and the other with a monobloc stem. Length was measured on the anteroposterior pelvic-bearing radiograph at six months. The mean of the measurements obtained for each arm of the cohort were compared with each other. Results: No statistically significant differences were observed in the correction of asymmetry between both groups, determined as the difference in length between the operated hip and the contralateral hip (P=.106). Nor were differences observed in postoperative length values (P=.053). It should be noted that for both the modular stem and the monobloc stem, the majority group is the one with restored length (84.1% and 80.4%, respectively; P=.001). Conclusion: Despite the theoretical advantage of modularity and that having interchangeable parts could be of great interest, in our study, we have not been able to demonstrate a superiority of modular designs compared to monoblock for control of postoperative leg length discrepancy.(AU)

[Translated article] Comparison of leg length discrepancy correction after the use of a modular neck stem and its monoblock homologue in total primary hip arthroplasty / Comparación de la corrección de la discrepancia de longitud de miembros tras el empleo de un vástago con cuello modular y su homólogo monobloque en la artroplastia total de cadera primaria

Introducción y objetivos: Los vástagos con doble modularidad buscan restaurar de forma más precisa la anatomía al permitir ajustes intraoperatorios gracias a los cuellos modulares. Nuestro objetivo es comparar la corrección radiográfica de la longitud con el vástago H MAX-M® frente a su homólogo monobloque H MAX-S®. Material y métodos: Se realizó un estudio de cohortes prospectivo mediante muestreo consecutivo sobre pacientes intervenidos de artroplastia total de cadera primaria con el diagnóstico de coxartrosis entre el año 2011 y 2015. Un brazo de la cohorte incluyó a los pacientes intervenidos con vástago modular y el otro con vástago monobloque. Se midió la longitud en la radiografía anteroposterior de pelvis en carga a los seis meses. Las medias de las mediciones obtenidas para cada brazo de la cohorte se compararon entre sí. Resultados: No se han observado diferencias estadísticamente significativas en la corrección de la disimetría entre ambos grupos determinada como la diferencia de longitud entre la cadera operada y la cadera contralateral (p=0,106). Tampoco se observaron diferencias en los valores postoperatorios de longitud (p=0,053). Cabe decir que tanto para el vástago modular como para el vástago monobloque el grupo mayoritario es aquel con longitud restaurada (84,1 y 80,4%, respectivamente; p=0,001). Conclusión: A pesar de la ventaja teórica de la modularidad y que disponer de piezas intercambiables podría ser de gran interés, en nuestro estudio no hemos podido demostrar que exista una superioridad de los diseños modulares frente al monoblock para control de la disimetría postoperatoria.(AU)

Introduction and objective: Dual modularity stems seek to more precisely restore anatomy by allowing intraoperative adjustments thanks to modular necks. Our aim is to compare the radiographic length correction with the H MAX-M® Stem versus its monoblock counterpart H MAX-S®. Material and methods: A prospective cohort study was carried out through consecutive sampling on patients who underwent primary total hip arthroplasty with coxarthrosis diagnosis between 2011 and 2015. One arm of the cohort included patients who were operated with a modular stem and the other with a monobloc stem. Length was measured on the anteroposterior pelvic-bearing radiograph at six months. The mean of the measurements obtained for each arm of the cohort were compared with each other. Results: No statistically significant differences were observed in the correction of asymmetry between both groups, determined as the difference in length between the operated hip and the contralateral hip (P=.106). Nor were differences observed in postoperative length values (P=.053). It should be noted that for both the modular stem and the monobloc stem, the majority group is the one with restored length (84.1% and 80.4%, respectively; P=.001). Conclusion: Despite the theoretical advantage of modularity and that having interchangeable parts could be of great interest, in our study, we have not been able to demonstrate a superiority of modular designs compared to monoblock for control of postoperative leg length discrepancy.(AU)

[Translated article] Comparison of leg length discrepancy correction after the use of a modular neck stem and its monoblock homologue in total primary hip arthroplasty.

INTRODUCTION AND OBJECTIVE: Dual modularity stems seek to more precisely restore anatomy by allowing intraoperative adjustments thanks to modular necks. Our aim is to compare the radiographic length correction with the H MAX-M® Stem versus its monoblock counterpart H MAX-S®. MATERIAL AND METHODS: A prospective cohort study was carried out through consecutive sampling on patients who underwent primary total hip arthroplasty with coxarthrosis diagnosis between 2011 and 2015. One arm of the cohort included patients who were operated with a modular stem and the other with a monobloc stem. Length was measured on the anteroposterior pelvic-bearing radiograph at 6 months. The mean of the measurements obtained for each arm of the cohort were compared with each other. RESULTS: No statistically significant differences were observed in the correction of asymmetry between both groups, determined as the difference in length between the operated hip and the contralateral hip (p=.106). Nor were differences observed in postoperative length values (p=.053). It should be noted that for both the modular stem and the monobloc stem, the majority group is the one with restored length (84.1% and 80.4%, respectively; p=.001). CONCLUSION: Despite the theoretical advantage of modularity and that having interchangeable parts could be of great interest, in our study, we have not been able to demonstrate a superiority of modular designs compared to monoblock for control of postoperative leg length discrepancy.

Comparison of leg length discrepancy correction after the use of a modular neck stem and its monoblock homologue in total primary hip arthroplasty. / Comparación de la corrección de la discrepancia de longitud de miembros tras el empleo de un vástago con cuello modular y su homólogo monobloque en la artroplastia total de cadera primaria.

INTRODUCTION AND OBJECTIVE: Dual modularity stems seek to more precisely restore anatomy by allowing intraoperative adjustments thanks to modular necks. Our aim is to compare the radiographic length correction with the H MAX-M® Stem versus its monoblock counterpart H MAX-S®. MATERIAL AND METHODS: A prospective cohort study was carried out through consecutive sampling on patients who underwent primary total hip arthroplasty with coxarthrosis diagnosis between 2011 and 2015. One arm of the cohort included patients who were operated with a modular stem and the other with a monobloc stem. Length was measured on the anteroposterior pelvic-bearing radiograph at six months. The mean of the measurements obtained for each arm of the cohort were compared with each other. RESULTS: No statistically significant differences were observed in the correction of asymmetry between both groups, determined as the difference in length between the operated hip and the contralateral hip (P=.106). Nor were differences observed in postoperative length values (P=.053). It should be noted that for both the modular stem and the monobloc stem, the majority group is the one with restored length (84.1% and 80.4%, respectively; P=.001). CONCLUSION: Despite the theoretical advantage of modularity and that having interchangeable parts could be of great interest, in our study, we have not been able to demonstrate a superiority of modular designs compared to monoblock for control of postoperative leg length discrepancy.

Comparison of the correction of the femoral offset after the use of a stem with modular neck and its monoblock homologue in total primary hip arthroplasty. / Comparación de la corrección del offset femoral tras el empleo de un vástago monobloque y un vástago con cuello modular en la artroplastia total de cadera primaria.

INTRODUCTION AND OBJECTIVE: Dual modularity stems were introduced with the theoretical advantage of restoring hip anatomy more precisely through femoral offset and limb length adjustment. Interchangeable necks allow for intraoperative angulation, anteversion and length changes. Our objective is to study whether a better femoral offset correction is achieved with the H MAX-M® prosthesis (Limacorporate, San Daniele, Italy) compared to its monoblock counterpart. MATERIAL AND METHODS: A prospective cohort study was conducted by means of consecutive sampling on adult patients undergoing total hip arthroplasty with the diagnosis of coxarthrosis between January 2011 and December 2015. This cohort has two arms, one arm included patients who underwent modular neck arthroplasty and the other included patients who underwent monoblock total hip arthroplasty. Radiographic offset measurement of the operated hip and the contralateral hip was performed, and the difference between both values was calculated. The mean of the measurements obtained for each arm of the cohort were compared with each other. RESULTS: No statistically significant differences were observed in the difference in offset between the operated hip and the contralateral hip (P=.323). No statistically significant differences were observed in the correction of the femoral offset, determined as the difference between the operated hip and the contralateral hip (P=.323). Nor were differences observed in the postoperative offset values (P=.097). It should be noted that for both designs, the majority group is the one with restored offset (P=.001).

Comparación de la corrección del offset femoral tras el empleo de un vástago monobloque y un vástago con cuello modular en la artroplastia total de cadera primaria / Comparison of the correction of the femoral offset after the use of a stem with modular neck and its monoblock homologue in total primary hip arthroplasty

Introducción y objetivos: Los vástagos con doble modularidad fueron introducidos con la ventaja teórica de restaurar de forma más precisa la anatomía de la cadera a través del ajuste del offset femoral y la longitud de miembros. Los cuellos intercambiables permiten cambios intraoperatorios de angulación, anteversión y longitud. Nuestro objetivo es estudiar si se consigue una mejor corrección del offset femoral con la prótesis H MAX-M® (Limacorporate, San Daniele, Italia) frente a su homólogo monobloque. Material y métodos: Se realizó un estudio de cohortes prospectivo mediante muestreo consecutivo sobre pacientes intervenidos de artroplastia total de cadera con el diagnóstico de coxartrosis desde enero de 2011 hasta diciembre 2015. Esta cohorte posee 2 brazos, un brazo incluyó a los pacientes intervenidos mediante vástago con cuello modular y el otro a los pacientes intervenidos mediante vástago monobloque. Se realizó la medición radiográfica del offset de la cadera intervenida, la cadera contralateral y se calculó la diferencia entre ambos valores. Las medias de las mediciones obtenidas para cada brazo de la cohorte se compararon entre sí. Resultados: No se han observado diferencias estadísticamente significativas en la corrección del offset femoral entre el grupo modular y monobloque, determinado como la diferencia de offset entre la cadera operada y la cadera contralateral (p=0,323). Tampoco se observaron diferencias en los valores de offset postoperatorio (p=0,097). Cabe decir que tanto para la prótesis modular como para la prótesis monobloque el grupo mayoritario es aquel con offset restaurado (p=0,001).(AU)

Introduction and objective: Dual modularity stems were introduced with the theoretical advantage of restoring hip anatomy more precisely through femoral offset and limb length adjustment. Interchangeable necks allow for intraoperative angulation, anteversion and length changes. Our objective is to study whether a better femoral offset correction is achieved with the H MAX-M® prosthesis (Limacorporate, San Daniele, Italy) compared to its monoblock counterpart. Material and methods: A prospective cohort study was conducted by means of consecutive sampling on adult patients undergoing total hip arthroplasty with the diagnosis of coxarthrosis between January 2011 and December 2015. This cohort has two arms, one arm included patients who underwent modular neck arthroplasty and the other included patients who underwent monoblock total hip arthroplasty. Radiographic offset measurement of the operated hip and the contralateral hip was performed, and the difference between both values was calculated. The mean of the measurements obtained for each arm of the cohort were compared with each other. Results: No statistically significant differences were observed in the difference in offset between the operated hip and the contralateral hip (P=.323). No statistically significant differences were observed in the correction of the femoral offset, determined as the difference between the operated hip and the contralateral hip (P=.323). Nor were differences observed in the postoperative offset values (P=.097). It should be noted that for both designs, the majority group is the one with restored offset (P=.001).(AU)

Comparison of the correction of the femoral offset after the use of a stem with modular neck and its monoblock homologue in total primary hip arthroplasty / Comparación de la corrección del offset femoral tras el empleo de un vástago monobloque y un vástago con cuello modular en la artroplastia total de cadera primaria

Introduction and objective: Dual modularity stems were introduced with the theoretical advantage of restoring hip anatomy more precisely through femoral offset and limb length adjustment. Interchangeable necks allow for intraoperative angulation, anteversion and length changes. Our objective is to study whether a better femoral offset correction is achieved with the H MAX-M® prosthesis (Limacorporate, San Daniele, Italy) compared to its monoblock counterpart. Material and methods: A prospective cohort study was conducted by means of consecutive sampling on adult patients undergoing total hip arthroplasty with the diagnosis of coxarthrosis between January 2011 and December 2015. This cohort has two arms, one arm included patients who underwent modular neck arthroplasty and the other included patients who underwent monoblock total hip arthroplasty. Radiographic offset measurement of the operated hip and the contralateral hip was performed, and the difference between both values was calculated. The mean of the measurements obtained for each arm of the cohort were compared with each other. Results: No statistically significant differences were observed in the difference in offset between the operated hip and the contralateral hip (P=.323). No statistically significant differences were observed in the correction of the femoral offset, determined as the difference between the operated hip and the contralateral hip (P=.323). Nor were differences observed in the postoperative offset values (P=.097). It should be noted that for both designs, the majority group is the one with restored offset (P=.001).(AU)

Introducción y objetivos: Los vástagos con doble modularidad fueron introducidos con la ventaja teórica de restaurar de forma más precisa la anatomía de la cadera a través del ajuste del offset femoral y la longitud de miembros. Los cuellos intercambiables permiten cambios intraoperatorios de angulación, anteversión y longitud. Nuestro objetivo es estudiar si se consigue una mejor corrección del offset femoral con la prótesis H MAX-M® (Limacorporate, San Daniele, Italia) frente a su homólogo monobloque. Material y métodos: Se realizó un estudio de cohortes prospectivo mediante muestreo consecutivo sobre pacientes intervenidos de artroplastia total de cadera con el diagnóstico de coxartrosis desde enero de 2011 hasta diciembre 2015. Esta cohorte posee 2 brazos, un brazo incluyó a los pacientes intervenidos mediante vástago con cuello modular y el otro a los pacientes intervenidos mediante vástago monobloque. Se realizó la medición radiográfica del offset de la cadera intervenida, la cadera contralateral y se calculó la diferencia entre ambos valores. Las medias de las mediciones obtenidas para cada brazo de la cohorte se compararon entre sí. Resultados: No se han observado diferencias estadísticamente significativas en la corrección del offset femoral entre el grupo modular y monobloque, determinado como la diferencia de offset entre la cadera operada y la cadera contralateral (p=0,323). Tampoco se observaron diferencias en los valores de offset postoperatorio (p=0,097). Cabe decir que tanto para la prótesis modular como para la prótesis monobloque el grupo mayoritario es aquel con offset restaurado (p=0,001).(AU)

Cheating interactions favor modularity in mutualistic networks / Las interacciones de engaño favorecen la modularidad en las redes mutualistas / Interações de trapaceiros favorece modularidade em redes de mutualismos

A fundamental fact about mutualisms is they are often explored by species that explore resources and services provided by individuals without providing any benefit. The role of these cheaters on the evolutionary dynamics of mutualisms has long been recognized, but cheaters may not only affect the species they explore. Because mutualisms form networks that often involve dozens to hundreds of species in a given site, indirect effects generated by cheaters may cascade through the network, reshaping trait evolution. Here, we study how harboring cheating interactions can influence coevolution in mutualistic networks. We combine a coevolutionary model, data on empirical networks of mutualisms, and numerical simulations to show that the higher frequency of cheating interactions can lead to the formation of groups of species phenotypically similar to each other but distinct from other groups of species, leading to higher trait disparity. The clustered trait patterns generated by cheaters, in turn, change the patterns of interaction in simulated networks, fostering the formation of modules of interacting species. Our results indicate that cheaters of mutualisms can contribute to generate phenotypic clusters in mutualisms, counteracting selection for convergence imposed by mutualistic patterns, and favoring the emergence of modules of interacting species.

Un hecho fundamental sobre los mutualismos es que muchas veces son explorados por especies que exploran recursos y servicios proporcionados por individuos sin proporcionar ningún beneficio. El papel de estos tramposos en la dinámica evolutiva de los mutualismos se ha reconocido desde hace mucho tiempo, pero es posible que los tramposos no solo afecten a las especies que exploran. Debido a que los mutualismos forman redes que muchas veces involucran decenas a cientos de especies en un sitio determinado, los efectos indirectos generados por los tramposos pueden caer en cascada a través de la red, remodelando la evolución de los rasgos. Aquí, estudiamos cómo albergar interacciones de engaño puede influir en la coevolución en redes mutualistas. Combinamos un modelo coevolutivo, datos sobre redes empíricas de mutualismos y simulaciones numéricas para mostrar que la mayor frecuencia de interacciones engañosas puede conducir a la formación de grupos de especies fenotípicamente similares entre sí pero distintos de otros grupos de especies, lo que conduce a mayores disparidad de rasgos. Los patrones de rasgos agrupados generados por los tramposos, a su vez, cambian los patrones de interacción en redes simuladas, fomentando la formación de módulos de especies que interactúan. Nuestros resultados indican que los tramposos de los mutualismos pueden contribuir a generar agrupaciones fenotípicas en mutualismos, contrarrestando la selección por convergencia impuesta por patrones mutualistas y favoreciendo la aparición de módulos de especies interactuantes.

Um fato fundamental sobre os mutualismos é que eles são frequentemente explorados por espécies que exploram recursos e serviços fornecidos por indivíduos sem fornecer qualquer benefício. O papel desses trapaceiros na dinâmica evolutiva dos mutualismos foi reconhecido há muito tempo, mas os trapaceiros podem não apenas afetar as espécies que exploram. Como os mutualismos formam redes que geralmente envolvem dezenas a centenas de espécies em um determinado local, os efeitos indiretos gerados por trapaceiros podem se espalhar pela rede, remodelando a evolução de características. Aqui, estudamos como considerar interações de trapaça pode influenciar a coevolução em redes mutualísticas. Combinamos um modelo coevolucionário, dados sobre redes empíricas de mutualismos e simulações numéricas para mostrar que a maior frequência de interações de trapaça pode levar à formação de grupos de espécies fenotipicamente semelhantes entre si, mas distintos de outros grupos de espécies, levando a disparidade de traço. Os padrões de características agrupados gerados por trapaceiros, por sua vez, alteram os padrões de interação em redes simuladas, promovendo a formação de módulos de espécies em interação. Nossos resultados indicam que trapaceiros de mutualismos podem contribuir para gerar grupos fenotípicos em mutualismos, contrariando a seleção para convergência imposta por padrões mutualísticos e favorecendo o surgimento de módulos de espécies interagentes.

Morfometría geométrica y sus nuevas aplicaciones en ecología y biología evolutiva: Parte 2 / Geometric morphometric and its new applications in ecology and evolutionary biology: Part 2

RESUMEN: La presente revisión entrega una visión actualizada del estudio de la morfometría geométrica y sus aplicaciones más actuales en ecología y biología evolutiva, metodología con una amplia variación en los últimos 5 años de su primera versión en International Journal of Morphology. La Morfometría geométrica es una herramienta que permite evaluar las variaciones morfológicas con factores subyacentes, siendo una herramienta más sensible que la morfometría tradicional, lo que permite detectar mínimos cambios de variación morfológica. Lo que la ha vuelto una herramienta notable para responder preguntas de biología comparada centradas en caracteres anatómicos. En sus comienzos fue una herramienta usada principalmente para responder preguntas taxonómicas, y para diferenciar a nivel de individuos, poblaciones o especies. No obstante, en los últimos años la cantidad de preguntas y problemáticas en las que se aplica, ha diversificado considerablemente, pasando a ser una herramienta muy precisa para responder preguntas de variación morfológica en contextos ecológicos y evolutivos. Ya ha pasado casi media década desde la última revisión del método, por lo que éste trabajo tiene como objetivo analizar los cambios metodológicos y los nuevos enfoques usados en Morfometría geométrica, y presentar una pequeña guía introductoria a éstos nuevos métodos, sus usos y aplicaciones.

SUMMARY: This study provides an updated vision of the study of Geometric Morphometrics and its most recent application in ecology and evolutionary biology, covering a wide variation in methodology occurring in the last 5 years since the first version published in the International Journal of Morphology. Geometric Morphometrics is a tool that allows evaluating morphological variations with underlying factors, with a higher sensitivity than traditional morphology, so that minimum changes of morphological variation can be detected. Therefore, it has turned into an outstanding tool to answer questions of comparative biology focused on anatomic characters. At the beginning, it was a tool mainly used to answer taxonomic questions and for differentiation at individual, population or species level. However, in the last years, the number of questions and problematic on which it is applied, has diversified considerably, turning it into a very accurate tool to answer questions of morphological variation in ecologic and evolutionary contexts. Almost half a decade has elapsed since the last revision of the method, so this work is intended to analyze the methodological changes and the new approaches used in Geometric Morphometrics, including a brief introductory guideline to these new methods, their uses and applications.

La arquitectura genética como herramienta de análisis del mapa genotipo-fenotipo / Genetic architecture as an analysis tool of the genotype-phenotype map

El estudio de la relación entre el genotipo y el fenotipo es de gran importancia para las investigaciones en genética y en las ciencias de la vida en general. A diferencia de la concepción tradicional de esta relación como un conjunto invariante de parámetros, el enfoque actual utiliza la arquitectura genética, una herramienta realista y dinámica que permite elucidar el mapa genotipo-fenotipo, ahora considerado una estructura en evolución. De las complejas relaciones entre los elementos del mapa genotipo-fenotipo surgen diversas propiedades emergentes que pueden explicar distintos fenómenos evolutivos. Además, algunas de estas propiedades promueven la acumulación de variabilidad genética en poblaciones naturales, la cual constituye el sustrato de procesos evolutivos como la selección natural. La caracterización y análisis de la arquitectura genética de caracteres adaptativos constituye una herramienta eficaz para comprender los procesos genéticos subyacentes al cambio evolutivo.

Studying the relationship between genotype and phenotype is of great importance for genetics and life science studies in general. In contrast with the traditional view of this relationship as an invariant set of parameters, the current approach incorporates the concept of genetic architecture, a realistic and dynamic tool that allows to elucidate the genotype-phenotype map, which is now regarded as an evolving structure. From the complex relationships between the elements in the genotype-phenotype map several emergent properties arise that can explain different evolutionary phenomena. Moreover, some of these properties promote the accumulation of genetic variability in natural populations, which constitutes the substrate to evolutionary processes such as natural selection. The characterization and analysis of the genetic architecture of adaptive traits constitutes a powerful tool to understand the genetics underpinnings of evolution.

Modelando la varianza de la forma: morfometría geométrica aplicaciones en biología evolutiva / Modelling shape variance: geometric morphometric applications in evolutionary biology

La comparación de caracteres anatómicos entre organismos ha sido un elemento central de la biología comparada. Históricamente, la clasificación taxonómica y la comprensión de la diversidad biológica se han basado en descripciones morfológicas. En base a una revolución matemática cuantitativa, el estudio de la morfología ha tenido un importante énfasis gracias al desarrollo del análisis de la forma mediante la combinación de métodos estadísticos multivariados y nuevas maneras de visualización. El objetivo de la presente revisión es dar una visión actualizada sobre los avances del estudio de la morfometría geométrica (MG) en biología evolutiva, así como introducir a temáticas en fuerte desarrollo (e.g. estabilidad del desarrollo, integración y modularidad morfológicas, entre otras). Se espera proporcionar una visión amplia del uso de la MG en biología evolutiva, destacando la necesidad de aumentar el esfuerzo de investigación en esta disciplina, junto con llamar la atención acerca de la utilidad de la MG como una herramienta efectiva, precisa, amigable y barata para cuantificar y estudiar la variación morfológica.

The comparison of anatomical traits between organisms has been a central topic in comparative biology. Historically, taxanomic classification and biological diversity understanding have been based on morphological descriptions. Derived from a mathematical quantitative revolution, morphological studies have experienced an important renewal due to the development of shape analysis rooted in statistical multivariate methods and novel visualisation techniques. The aim of the present review is to provide an updated perspective regarding the progress in geometric morphometrics (GMM) applied to evolutionary biology, as well as introducing to cutting-edge subjects (e.g. developmental stability, modularity, morphological integration, among other themes). Thus, it is expected to provide a broad point of view with respect to the appliaction of geometric morphometrics in evolutionary biology, highlighting its usefulness as an effective, accurate, user-friendly and inexpensive method to quantify and study shape variation.

The asymmetry and modularity of the hyoid bone / Asimetría y modularidad del hueso hioides

Morphological variation is a result of interplay among multiple intervening factors. For hyoid bones, the shape and size differences have been scarcely covered in the literature and in majority limited to studies of sexual dimorphism or age dependency. To our knowledge, the human hyoid bone, in complete opposite to other cranial bones, has not been fully utilized to address development questions in terms of asymmetry or modularity. In the present paper, we used landmark-based methods of geometric morphometrics and multivariate statistical approach to study human hyoid morphology represented by the hyoid body and greater horns in a sample of 211 fused and non-fused bones. Within a sample variation analysis, we showed that the hyoid bone is, by nature, asymmetrical bone which exhibits both directional and fluctuating types of asymmetry and is composed of well-integrated anatomical elements for which the biomechanical load of attached muscles is the most determining factor of variation. Yet, the covariance and evidence of unequal amount of fluctuating asymmetry among modules suggests a certain degree of independence during early stages of development.

La variación morfológica es el resultado de la interacción entre múltiples factores. Para huesos hioides, las diferencias de forma y tamaño han sido poco mencionadas en la literatura y se limitan a estudios del dimorfismo sexual o distribución etaria. Hasta donde sabemos, el hueso hioides humano, a diferencia de otros huesos craneales, no ha sido utilizado para hacer frente a interrogantes del desarrollo en términos de asimetría o de la modularidad. Utilizamos métodos basados en hitos de la morfometría geométrica y en el enfoque estadístico multivariado para estudiar la morfología del hueso hioides humano, representado por el cuerpo del hioides y astas mayores, en una muestra de 211 huesos fusionados y no fusionados. En un análisis de la variación de la muestra, se demostró que el hueso hioides es por naturaleza un hueso asimétrico, que exhibe tipos de asimetría tanto direccionales y fluctuantes, compuesto de elementos anatómicos bien integrados para los cuales, la carga biomecánica de músculos vinculados es el factor más determinante de la variación. Sin embargo, la covarianza y la evidencia de la cantidad desigual de asimetría fluctuante entre módulos sugiereun cierto grado de independencia durante las primeras etapas de desarrollo.

Modularidad e integración morfológica en cráneos humanos: un enfoque morfométrico geométrico / Modularity and morphological integration in human skulls: a geometric morphometric approach

Los conceptos de integración y modularidad refieren al grado de covariación entre los componentes de una estructura. Los módulos morfológicos son aquellas estructuras que poseen componentes que covarían fuertemente, pero que a su vez son relativamente independientes de otros módulos. Mientras que por integración morfológica se entiende a la variación morfológica coordinada de los componentes de un todo funcional. En el caso del cráneo se han definido tradicionalmente dos módulos en base a su origen embrionario diferencial: el esplacnocráneo y el neurocráneo. Se ha sugerido que el desarrollo cráneofacial es altamente integrado, tanto funcional como ontogénicamente. Se puso a prueba la hipótesis de modularidad del desarrollo del cráneo en base a orígenes embrionarios diferenciales, mediante la utilización del coeficiente RV. Posteriormente se evaluó el nivel de integración morfológica entre los módulos definidos anteriormente, mediante un análisis de dos bloques de mínimos cuadrados (PLS). Se intentó conocer así, si la tradicional división entre esplacno y neurocráneo posee un fundamento modular, así como el respectivo nivel de integración morfológica entre ambas estructuras.

Morphological Integration and modularity are concepts that refer to the covariation level between the components of a structure. Morphological modules are those structures that have components that strongly covary, which in turn are relatively independent to other modules. Morphological integration is instead, the coordinated morphological variation of a functional whole. Traditionally the skull has been divided in two modules based on their different developmental origins: the splanchnocranium and the neurocranium. It has been suggested that the craniofacial development is highly integrated both functional as ontogenetically. The modularity hypothesis based on different developmental origins was tested, by using the RV coefficient. Later, the integration level was assessed applying a partial least-squares analysis (PLS). The underlying aim was to know whether the traditional division between splanchno and neurocranium has a modular basis, as well as the morphological integration level between these two structures.

La modularidad y la realidad de los procesos psicológicos / A modularidade e a realidade dos processos psicológicos / Modularity and the reality of psychological processes

Este texto ofrece un escenario para el debate sobre el estatus de la noción de proceso psicológico a partir del enfoque de modularidad, asumida en cierta medida en la psicología contemporánea, que pone de manifiesto un compromiso con alguna variedad de arquitectura cognitiva. La modularidad fuerte ha sido un enfoque moderadamente exitoso, pero también ha conducido a una comprensión fragmentada de la mente y el comportamiento, insuficiente para fundamentar la práctica profesional en diversas áreas de la psicología. La modularidad débil, como hipótesis de trabajo y alternativa, puede ser una estrategia de investigación útil, pero también requiere la integración de los hallazgos de la investigación en psicología en un marco coherente. Se discuten las implicaciones de este debate en la enseñanza de la psicología.

The objective of this paper is to set the stage for a discussion of the status of the idea of psychological process within psychological explanations and descriptions, indicating some of its consequences for the teaching of psychology. It is argued that contemporary psychology espouses some form of modularity, which, in turn, reveals commitments to a particular variety of cognitive architecture. The assumption of modularity has been a fruitful approach in some areas (e. g. the study of perception), but it has also led to a piecemeal understanding of mind and behavior that is simply insufficient to provide foundations for professional practice in several areas of psychology (e. g. education). Whereas assuming weak modularity as a working hypothesis might be a useful and necessary research strategy, integrating psychological research findings into a coherent framework is necessary. This idea has important consequences for the teaching of psychology.

Este texto oferece um cenário para o debate sobre o status da noção de processo psicológico a partir do enfoque da modularidade, assumida em certa medida na psicologia contemporânea, que manifestou um compromisso com alguma variedade da arquitetura cognitiva. A modularidade forte tem sido um enfoque moderadamente exitoso, mas também tem conduzido a uma compreensão fragmentada da mente e do comportamento, insuficiente para fundamentar a prática profissional em diversas áreas da psicologia. Amodularidade fraca, como hipótese de trabalho e alternativa, pode ser uma estratégia de investigação útil, mas também requer a integração das descobertas de investigação em psicologia num marco coerente. Discutem-se as implicações deste debate no ensino de psicologia.

Debates sobre la modularidad en Psicología del Desarrollo: ¿Hacia un nuevo constructivismo? / Debates on modularity in Developmental Pychology: To a new constructivism?

El presente trabajo informa acerca del estado de los debates sobre la modularidad y sus implicaciones en Psicología del Desarrollo, en particular aplicada a la comprensión del desarrollo cognitivo. En primer lugar se examina el surgimiento y desarrollo de una hegemonía modularista dentro de la Psicología Cognitiva del Desarrollo, revisando hipótesis acerca de la arquitectura mental que surgen del trabajo teórico de Fodor (1983 / 1986) y de la investigación empírica que indica la existencia de estructuras y contenidos innatos en bebés. Las contribuciones del paradigma modularista llevan al reconocimiento de diferencias entre la consideración del bebé como tabla rasa, propia de las teorías piagetiana y conductista y un nuevo bebé innatista con competencias iniciales mucho más poderosas. Explicar en qué consiste el desarrollo cognitivo implica ahora un difícil equilibrio, ya que cuantas más propiedades de dominio específico se reconozcan en la mente del bebé, es decir, cuanto más modularizada esté la mente al comienzo del desarrollo, menos creativo y flexible será el sistema posterior. La hipótesis de la modularización de Karmiloff-Smith (1992 / 1994) puede servir para considerar la modularidad (redefinida) como el producto natural del proceso mismo de desarrollo. Es necesario continuar el debate para replantear un modelo constructivista, más aquí o más allá de la modularidad a lo Fodor, pero también de Piaget y del paradigma computacional, que responda al mismo tiempo a las actuales posibilidades de investigación de la Neurobiología del Desarrollo. Como consecuencia, probablemente el mismo papel de la Psicología del Desarrollo en el debate lleve a redefinir el alcance de esta disciplina, trascendiendo (aunque sin abandonar) su marco computacional de referencia.

This work communicates some discussions on modularity and its implications in Developmental Psychology, particularly applied to the understanding of cognitive development. First, we review some reasons for the emergence and expansion of a modular hegemony within the Developmental Cognitive Psychology the last two decades. We examine both assumptions about the mental architecture arising from the theoretical work of Fodor (1983 / 1986), as well as empirical research that indicates the existence of innate structures and contents in babies. While reviewing critically various modular models, we consider such hegemony and open lines of the debate. Progress of the modularity has led in different directions and disciplines within the cognitive sciences. On the one hand, much of the psychological research was conducted to search for modules, going against the general domain paradigm of long tradition. Theorizing was a dramatic turnaround beyond Fodor, assuming the hypothesis of massive modularity, which maintains the mind consists essentially (or may be completely) by innate modules for specific purposes. Modularity also appears as encouragement of investigations in the field of Neurobiology, working steadily on pathological cases such as double dissociations or atypical development (vg. Williams Syndrome). There are also positions of soft modularity, like the assumption of modularization of Karmiloff-Smith -which seems to have marked a turning point in the dynamics of theorizing and experimentation on the subject in question. Contributions from the paradigm of modularity led to estimate the differences between baby's consideration as a blank slate without any previous knowledge- the Piagetian and behaviorist babies, and a new nativist baby, initially much more powerful. For the standard constructivism, mind development occurs by general changes that affect the general structures of representation for all domains, and that operate on all aspects of cognitive system similarly, from a few processes biologically determined and functional processes as invariant. For the nativist / modular thesis, the baby is much better equipped from this starting, and is programmed to understand specific sources of information; their further development will be restricted by the specific innately modules established for each domain. To explain cognitive development would involve a difficult balance: while there are more specific domain properties in the baby's mind, less creative and flexible will be their cognitive system. Neuroscience of development and recent experiments with babies, provide elements to try reconciliation between their explanation of the constructivist legacy and the new findings about the innate background of the babies. The evolutionary specialization of human beings would be characterized precisely by a relative lack of expertise at birth, and a very lengthy development during which our brains learn and configure out. So, it would be possible to stay (or return) to constructivist positions, without abandoning the notion that there is something innate -although not necessarily coincident with the Fodor's view. This approach is borrowing heavily from the idea of modularization of Karmiloff-Smith (1992 / 1994). She proposed that the domain expertise and modularity (re-defined) may well be understood as the natural product of the process of development. According to this author, modularization is the result of a process of representational redescription, a phased-development mechanism, able to give an account of the genesis of flexibility and variety of human cognition. Perhaps the challenge will be continuing with the debate in order to figure out the core features of a renewed constructivism, within or beyond the Fodorian modularity, but also of Piaget and computational paradigm, that considers modularistic contributions, and it is compatible with psychological and neurobiological theories. As a result, probably the same role of Developmental Psychology in this debate will lead to redefine the scope of this discipline, transcending (but not abandon) its computational framework.