Mejora significativa de la estabilidad a carga axial con el fijador externo pélvico pretensado: análisis biomecánico en un modelo con lesión Tile tipo C / Significant improvement in axial load stability with the pre-tensioned pelvic external fixator: A biomechanical analysis in a model with type C Tile lesion

Objetivo: Comprobar si la aplicación de fijación externa mediante barra curva conectada a clavos de Schanz supraacetabulares confiere mayor estabilidad al anillo pélvico con una lesión tipo Tile C1 cuando se realiza el montaje con la barra pretensada que con el montaje estándar (sin pretensar). Material y métodos: Pelvis sintéticas (N=5) con lesión verticalmente inestable estabilizada con ambos montajes, se sometieron a carga axial progresiva. Se midieron las fuerzas aplicadas y las variaciones en las posiciones de marcadores situados en la articulación sacroilíaca y la sínfisis se registraron con un sistema óptico. Se determinaron los desplazamientos relativos entre las superficies lesionadas, la rigidez, la resistencia y el modo de fallo de cada montaje. Resultados: Con el fijador pretensado, la rigidez del montaje en la articulación sacroilíaca resultó muy superior a la del montaje convencional (p=0,043) multiplicándola por 3,45, siendo 2,06 veces mayor en la sínfisis. La resistencia ante el fallo también fue superior, multiplicándola por 2 (p=0,043). Discusión: El aumento de estabilidad a carga axial con el fijador externo pretensado concuerda con su capacidad de producir compresión activa simultánea en los elementos posteriores y anteriores del anillo pélvico, demostrada previamente. Este resultado soporta los excelentes resultados clínicos preliminares obtenidos como tratamiento provisional. Conclusiones: El fijador externo pretensado aumenta la estabilidad axial de los elementos óseos posteriores del anillo pélvico con lesión tipo Tile C1 en modelo sintético, sin disminuir la capacidad de estabilización anterior propia de la fijación externa anterior.(AU)

Objective: The aim of our work is to check if the use of a pre-tensed bar connected to 2supra-acetabular Schanz pins is more stable in a pelvic with a tile C1 injury. Material and methods: We used synthetic pelvis (N=5) with a unstable vertical injury, stabilized with both the standard and the pre-tensed system. They both were submitted to axial loading. We measured applied forces and the position of markers that were positioned in the sacroiliac and symphysis joints. We determined the relative movements between injured surfaces, rigidity, resistance and when each system failed. Results: When using the pre-tensed fixator, the rigidity was much higher in the sacro-iliac joint (P=.043) being 3.45 times higher, being also 2.06 times higher in pubic symphysis (P=.043). The resistance against failure was 2 times higher too (P=.043). Discussion: The increased axial stability with the pre-tensed external fixator accords with its ability to make active compression in both posterior and anterior elements of the pelvic ring, which was previously demonstrated. This result supports the preliminary clinic outcomes that were obtained. Conclusions: The pre-tensed external fixator increases the axial stability of the pelvic ring's posterior elements in a synthethic pelvis with a Tile C1 injury, without decreasing it's capacity to achieve an anterior stability.(AU)

[Translated article] Significant improvement in axial load stability with the pre-tensioned pelvic external fixator: A biomechanical analysis in a model with type C Tile lesion / Mejora significativa de la estabilidad a carga axial con el fijador externo pélvico pretensado: análisis biomecánico en un modelo con lesión Tile tipo C

Objetivo: Comprobar si la aplicación de fijación externa mediante barra curva conectada a clavos de Schanz supraacetabulares confiere mayor estabilidad al anillo pélvico con una lesión tipo Tile C1 cuando se realiza el montaje con la barra pretensada que con el montaje estándar (sin pretensar). Material y métodos: Pelvis sintéticas (N=5) con lesión verticalmente inestable estabilizada con ambos montajes, se sometieron a carga axial progresiva. Se midieron las fuerzas aplicadas y las variaciones en las posiciones de marcadores situados en la articulación sacroilíaca y la sínfisis se registraron con un sistema óptico. Se determinaron los desplazamientos relativos entre las superficies lesionadas, la rigidez, la resistencia y el modo de fallo de cada montaje. Resultados: Con el fijador pretensado, la rigidez del montaje en la articulación sacroilíaca resultó muy superior a la del montaje convencional (p=0,043) multiplicándola por 3,45, siendo 2,06 veces mayor en la sínfisis. La resistencia ante el fallo también fue superior, multiplicándola por 2 (p=0,043). Discusión: El aumento de estabilidad a carga axial con el fijador externo pretensado concuerda con su capacidad de producir compresión activa simultánea en los elementos posteriores y anteriores del anillo pélvico, demostrada previamente. Este resultado soporta los excelentes resultados clínicos preliminares obtenidos como tratamiento provisional. Conclusiones: El fijador externo pretensado aumenta la estabilidad axial de los elementos óseos posteriores del anillo pélvico con lesión tipo Tile C1 en modelo sintético, sin disminuir la capacidad de estabilización anterior propia de la fijación externa anterior.(AU)

Objective: The aim of our work is to check if the use of a pre-tensed bar connected to 2supra-acetabular Schanz pins is more stable in a pelvic with a tile C1 injury. Material and methods: We used synthetic pelvis (N=5) with a unstable vertical injury, stabilized with both the standard and the pre-tensed system. They both were submitted to axial loading. We measured applied forces and the position of markers that were positioned in the sacroiliac and symphysis joints. We determined the relative movements between injured surfaces, rigidity, resistance and when each system failed. Results: When using the pre-tensed fixator, the rigidity was much higher in the sacro-iliac joint (P=.043) being 3.45 times higher, being also 2.06 times higher in pubic symphysis (P=.043). The resistance against failure was 2 times higher too (P=.043). Discussion: The increased axial stability with the pre-tensed external fixator accords with its ability to make active compression in both posterior and anterior elements of the pelvic ring, which was previously demonstrated. This result supports the preliminary clinic outcomes that were obtained. Conclusions: The pre-tensed external fixator increases the axial stability of the pelvic ring's posterior elements in a synthethic pelvis with a Tile C1 injury, without decreasing it's capacity to achieve an anterior stability.(AU)

Significant improvement in axial load stability with the pre-tensioned pelvic external fixator: A biomechanical analysis in a model with type C Tile lesion. / Mejora significativa de la estabilidad a carga axial con el fijador externo pélvico pretensado: análisis biomecánico en un modelo con lesión Tile tipo C.

OBJECTIVE: The aim of our work is to check if the use of a pre-tensed bar connected to 2supra-acetabular Schanz pins is more stable in a pelvic with a tile C1 injury. MATERIAL AND METHODS: We used synthetic pelvis (N=5) with a unstable vertical injury, stabilized with both the standard and the pre-tensed system. They both were submitted to axial loading. We measured applied forces and the position of markers that were positioned in the sacroiliac and symphysis joints. We determined the relative movements between injured surfaces, rigidity, resistance and when each system failed. RESULTS: When using the pre-tensed fixator, the rigidity was much higher in the sacro-iliac joint (P=.043) being 3.45 times higher, being also 2.06 times higher in pubic symphysis (P=.043). The resistance against failure was 2 times higher too (P=.043). DISCUSSION: The increased axial stability with the pre-tensed external fixator accords with its ability to make active compression in both posterior and anterior elements of the pelvic ring, which was previously demonstrated. This result supports the preliminary clinic outcomes that were obtained. CONCLUSIONS: The pre-tensed external fixator increases the axial stability of the pelvic ring's posterior elements in a synthethic pelvis with a Tile C1 injury, without decreasing it's capacity to achieve an anterior stability.

[Translated article] Significant improvement in axial load stability with the pre-tensioned pelvic external fixator: A biomechanical analysis in a model with type C Tile lesion.

OBJECTIVE: The aim of our work is to check if the use of a pre-tensed bar connected to 2 supra-acetabular Schanz pins is more stable in a pelvic with a tile C1 injury. MATERIAL AND METHODS: We used synthetic pelvis (N = 5) with a unstable vertical injury, stabilized with both the standard and the pre-tensed system. They both were submitted to axial loading. We measured applied forces and the position of markers that were positioned in the sacroiliac and symphysis joints. We determined the relative movements between injured surfaces, rigidity, resistance and when each system failed. RESULTS: When using the pre-tensed fixator, the rigidity was much higher in the sacro-iliac joint(P=.043) being 3.45 times higher, being also 2.06 times higher in pubic symphysis (P=.043). The resistance against failure was 2 times higher too (P=.043). DISCUSSION: The increased axial stability with the pre-tensed external fixator accords with its ability to make active compression in both posterior and anterior elements of the pelvic ring, which was previously demonstrated. This result supports the preliminary clinic outcomes that were obtained. CONCLUSIONS: The pre-tensed external fixator increases the axial stability of the pelvic ring's posterior elements in a synthethic pelvis with a Tile C1 injury, without decreasing it's capacity to achieve an anterior stability.