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.

Comparison of chromium and cobalt serum levels between a modular neck stem and its monoblock counterpart in primary total hip arthroplasty.

BACKGROUND: The addition of junctions in modular stems implies a greater susceptibility to corrosion. PURPOSE: The aim of this study is to compare serum chromium and cobalt levels after using a bimodular stem and its monoblock counterpart in primary total hip arthroplasty. Postoperative clinical scores were also compared. PATIENTS AND METHODS: A prospective cohort study between 2012 and 2015 was designed. One arm of the cohort included patients with the cementless modular neck stem H-Max M® and the other with the cementless monoblock stem counterpart H-Max S®. RESULTS: No statistically significant difference was found in chromium value between groups (p = 0.621) at two years postoperative. Cobalt value was higher in the modular group (p = < 0.001). No statistically significant difference was found in clinical postoperative scores except for the Harris Hip Score, with better results at six months in modular group (p = 0.007). CONCLUSIONS: Higher serum cobalt level in the modular group has limited the use of modular stems in our daily practice. Advantages of modular stem were not found. LEVEL OF EVIDENCE: II.

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)

Angiomiolipoma renal atípico versus carcinoma de células renales: dilema diagnóstico. Hallazgos útiles por tomografía computada para la discriminación de estos tumores / Atypical renal angiomyolipoma versus carcinoma renal cell: diagnosis dilemma. Findings by computed tomography for the discrimination of these tumors

Objetivo: Diferenciar el angiomiolipoma atípico del carcinoma de células renales del mismo tamaño mediante hallazgos tomográficos. Materiales y métodos: Se realizó un estudio retrospectivo con 68 pacientes (17 con angio-miolipomas atípicos y 51 con carcinoma de células renales) nefrectomizados por diagnóstico presuntivo preoperatorio, mediante tomografía computada trifásica (fases sin contraste, corticomedular y excretora temprana), de carcinoma de células renales menor de 45mm. Dos radiólogos que desconocían el diagnóstico definitivo evaluaron retrospectivamente las características generales del tumor, su atenuación en fase sin contraste y las características de su realce. Se realizó un análisis estadístico con software R, aplicándose el modelo logit para diferenciar el angiomiolipoma atípico del carcinoma de células renales a partir de los hallazgos tomográficos de masa renal, incluidos en el modelo final el contorno, la atenuación en fase sin contraste y el patrón de realce con el tiempo. Resultados: Los hallazgos de angiomiolipoma atípico que resultaron significativos fueron atenuación tumoral en fase sin contraste hiperdensa y patrón de realce con tiempo prolongado con chance de ocurrencia de 10,49 (p=0,0381) y 36,71 (p=0,0009), respectivamente. En los pacientes, según el valor de cada hallazgo incluido en el modelo, se calculó probabilidad, sensibilidad (0,2941) y especificidad (0,9804). La curva característica operativa del receptor (ROC) determinó un punto de corte óptimo (0,9694) para discriminar el angiomiolipoma atípico, por lo que se confirmó su presencia. Conclusión: La tomografía computada helicoidal trifásica es útil para diferenciar el angiomiolipoma atípico del carcinoma de células renales, siendo la atenuación hiperdensa sin contraste del tumor y su patrón de realce prolongado los hallazgos tomográficos más valiosos.

Objective: To compare various computed tomographic features of atypical angiomyolipoma with those of size-matched renal cell carcinoma. Materials and methods: Sixty-eight patients (17 with atypical angiomyolipomas and 51 with carcinoma renal cells) who had undergone nephrectomy by presumptive diagnosis of carcinoma renal cell<45mm on diameter by preoperative triphasic computed tomography (CT) (with unenhanced, corticomedullary, and early excretory phase scanning) were evaluated in a retrospective study. Two reviewers who were unaware of the diagnosis retrospectively recorded tumor attenuation on unenhanced scans, enhancement characteristics and general characteristics of the tumor. Statistical analysis was performed with R software, applying logit model to differentiate atypical angiomyolipoma from renal cell carcinoma from CT findings of renal mass, included in the final model the tumor margin, its attenuation on unenhanced scans and the enhancement pattern over time. Results: For atypical angiomyolipomas the most valuable CT findings were hyperdense attenuation tumour in unenhaced phase scan and prolonged enhancement pattern, with chance of occurrence of 10.49 (p=0.0381) and 36.71 (p=0.0009), respectively. In the patients, as each finding value in the model, probability, sensitivity (0.2941) and specificity (0.9804) was calculated ROC curve was constructed that determined optimal cutoff (0.9694) to discriminate atypical angiomyolipoma, confirming their presence. Conclusion: Triphasic helical CT may be useful in differentiating atypical angiomyolipoma from renal cell carcinoma, with hyperdense tumor attenuation on unenhanced scans and prolonged enhancement pattern being the most valuable CT findings.

Effects of serine protease inhibitors on viability and morphology of Leishmania (Leishmania) amazonensis promastigotes.

To investigate the importance of serine proteases in Leishmania amazonensis promastigotes, we analyzed the effects of classical serine protease inhibitors and a Kunitz-type inhibitor, obtained from sea anemone Stichodactyla helianthus (ShPI-I), on the viability and morphology of parasites in culture. Classical inhibitors were selected on the basis of their ability to inhibit L. amazonensis serine proteases, previously described. The N-tosyl-L: -phenylalanine chloromethyl ketone (TPCK) and benzamidine (Bza) inhibitors, which are potential Leishmania proteases inhibitors, in all experimental conditions reduced the parasite viability, with regard to time dependence. On the other hand, N-tosyl-lysine chloromethyl ketone (TLCK) did not significantly affect the parasite viability, as it was poor Leishmania enzymes inhibitor. Ultrastructural analysis demonstrated that both Bza and TPCK induced changes in the flagellar pocket region with membrane alteration, including bleb formation. However, TPCK effects were more pronounced than those of Bza in Leishmania flagellar pocket in plasma membrane, and intracellular vesicular bodies was visualized. ShPI-I proved to be a powerful inhibitor of L. amazonensis serine proteases and the parasite viability. The ultrastructural alterations caused by ShPI-I were more dramatic than those induced by the classical inhibitors. Vesiculation of the flagellar pocket membrane, the appearance of a cytoplasmic vesicle that resembles an autophagic vacuole, and alterations of promastigotes shape resulted.

Characterization of an extracellular serine protease of Leishmania (Leishmania) amazonensis.

A serine protease was purified 942-fold from culture supernatant of L. amazonensis promastigotes using (NH4)2SO4 precipitation followed by affinity chromatography on aprotinin-agarose and continuous elution electrophoresis by Prep Cell, yielding a total recovery of 61%. The molecular mass of the active enzyme estimated by SDS-PAGE under conditions of reduction was 56 kDa and 115 kDa under conditions of non-reduction, suggesting that the protease is a dimeric protein. Additionally, it was found to be a non-glycosylated enzyme, with a pI of 5.0. The optimal pH and temperature of the enzyme were 7.5 and 28 degrees C respectively, using alpha-N-rho-tosyl-L-arginine-methyl ester (L-TAME) as substrate. Assays of thermal stability indicated that 61% of the enzyme activity was preserved after 1 h of pre-treatment at 42 degrees C. Haemoglobin, bovine serum albumin (BSA), ovalbumin, fibrinogen, collagen, gelatin and peptide substrates containing arginine in an ester bond and amide substrates containing hydrophobic residues at the P1 site were hydrolysed by this extracellular protease. The insulin beta-chain was also hydrolysed by the enzyme and many peptidic bonds were susceptible to the protease action, and 4 of them (L11-V12, E3-A14, L15-Y16 and Y16-L17) were identified. Inhibition studies suggested that the enzyme belongs to the serine protease class inhibited by calcium and manganese and activated by zinc. These findings show that this enzyme of L. amazonensis is a novel serine protease, which differs from all known flagellate proteases characterized.

Subcellular localization of an extracellular serine protease in Leishmania (Leishmania) amazonensis.

Extracellular proteolytic activity was detected in a Leishmania ( L.) amazonensis culture supernatant and a 56-kDa protein was purified using (NH4)2SO4 precipitation followed by affinity chromatography on aprotinin-agarose. A rabbit serum obtained against the 56-kDa extracellular serine protease was used in order to analyze its location in L. ( L.) amazonensis parasites. Immunocytochemistry studies revealed that the enzyme is mainly found in the flagellar pocket and cytoplasmic vesicles of promastigote forms, whereas in amastigotes, it is located in electron-dense structures resembling megasomes. These results indicate that the 56-kDa serine protease is released into the extracellular environment through the flagellar pocket; and its intracellular location suggests either a correlated enzymatic activity or intracellular trafficking.

National athletic trainers' association position statement: lightning safety for athletics and recreation.

OBJECTIVE: To educate athletic trainers and others about the dangers of lightning, provide lightning-safety guidelines, define safe structures and locations, and advocate prehospital care for lightning-strike victims. BACKGROUND: Lightning may be the most frequently encountered severe-storm hazard endangering physically active people each year. Millions of lightning flashes strike the ground annually in the United States, causing nearly 100 deaths and 400 injuries. Three quarters of all lightning casualties occur between May and September, and nearly four fifths occur between 10:00 AM and 7:00 PM, which coincides with the hours for most athletic or recreational activities. Additionally, lightning casualties from sports and recreational activities have risen alarmingly in recent decades. RECOMMENDATIONS: The National Athletic Trainers' Association recommends a proactive approach to lightning safety, including the implementation of a lightning-safety policy that identifies safe locations for shelter from the lightning hazard. Further components of this policy are monitoring local weather forecasts, designating a weather watcher, and establishing a chain of command. Additionally, a flash-to-bang count of 30 seconds or more should be used as a minimal determinant of when to suspend activities. Waiting 30 minutes or longer after the last flash of lightning or sound of thunder is recommended before athletic or recreational activities are resumed. Lightning- safety strategies include avoiding shelter under trees, avoiding open fields and spaces, and suspending the use of land-line telephones during thunderstorms. Also outlined in this document are the prehospital care guidelines for triaging and treating lightning-strike victims. It is important to evaluate victims quickly for apnea, asystole, hypothermia, shock, fractures, and burns. Cardiopulmonary resuscitation is effective in resuscitating pulseless victims of lightning strike. Maintenance of cardiopulmonary resuscitation and first-aid certification should be required of all persons involved in sports and recreational activities.

Safety in the presence of lightning.

Not enough emphasis is usually placed on the proactive ability to recognize the lightning hazard. Instead, most literature and training materials treat the reactive mode. The latter approach emphasizes the posture to take when a person is caught by surprise in the open by a thunderstorm when the lightning threat is at its greatest; in other words, it is too late for precautions. The same reactive approach concentrates on what a person is wearing or holding when lightning is overhead instead of how the person came to be in this situation in the first place. Rather than focusing on these last-minute factors, the primary issue must be on the ability of a person, whether in a baseball game, riding a bike, or on a golf course, to recognize in advance the existence of a major lightning threat. This proactive approach emphasizes advance planning and recognition of a potential threat from lightning. A complete plan involves a sequence of decisions on a time scale from days to seconds. Although most of the available information in pamphlets and safety guidelines is correct concerning the reactive phase of lightning safety, the hazard remains important because of the lack of emphasis on planning and awareness.

[Applied anatomy for the radiologic and computed tomography study of the paranasal sinuses]. / Anatomía aplicada al estudio radiológico y la tomografía computada de los senos paranasales.

The current diagnosis by images has a significant importance in the medical and/or surgical treatment of the sinusal incidences due to its great sensibility to detect local pathological signs, their limits and neighboring relations. These data are of unvaluable importance at the moment of a therapeutical decision and should be based upon common interests among otorrhinolaringologists and neuroradiologists, speaking the common language given by a firm and shared knowledge of regional anatomy. This presentation is based on the comparison between drawings which show the essential anatomical data and the computed tomography findings, supplying the necessary technical data to obtain veracious images which coincide with the surgeons' angle of view in the direct as well as in the endoscopic approach.