Comparison of ultrasound and fluoroscopic guidance for injection in CT arthrography and MR arthrography of the hip. / Comparación de las técnicas de inyección ecográfica y radioscópica en artro-TC y artro-RM de cadera.

OBJECTIVE: To evaluate the usefulness of ultrasound-guided versus fluoroscopy-guided injection in CT arthrography and MR arthrography. MATERIAL AND METHODS: We reviewed all CT arthrography and MR arthrography studies done at our center between October 1, 2014 and October 1, 2015. We analyzed 32 studies: 26 with fluoroscopic guidance and 6 with ultrasound guidance. We compared the two techniques on the following parameters: presence of sufficient contrast material in the joint, extravasation or injection of contrast material in the soft tissues (presence of contrast material in the psoas or other soft tissues), and intra-articular gas bubbles. We used SPSS V. 20 to compare the techniques with Pearson's chi-square tests. RESULTS: Contrast material was observed in soft tissues in 56.3% of ultrasound-guided injections, making 6.3% of the procedures invalid for diagnostic purposes. Extravasation of contrast material was observed in 53.8% of fluoroscopy-guided procedures, making 3.8% invalid for diagnostic purposes. Intra-articular gas was observed in 21.9% of ultrasound-guided studies and in 38.5% of fluoroscopy-guided studies. None of the differences between techniques were statistically significant at p<0.05. CONCLUSIONS: Our study shows that ultrasound is as useful as fluoroscopy for injecting contrast material for CT arthroscopy and MR arthroscopy; ultrasound has the advantage of not using ionizing radiation.

Total hip arthroplasty in patients under 50 years old: Does cementless fixation have better results? / Reemplazo total de cadera en pacientes menores de 50 años: ¿tiene la fijación no cementada mejores resultados?

BACKGROUND: Cementless fixation for hip arthroplasties has increased in the last decades, particularly in younger patients. The purpose of this study was to compare the long-term results three different types of fixations in patients under 50years old. METHODS: Cemented, hybrid and cementless fixations were assessed in patients under 50years old with a minimum follow-up of 8years. Loosening, demarcation, complications, and prosthesis survival were assessed. Functional analysis was performed with the modified Harris Hip Score and Visual analogue scale was collected. RESULTS: Final series consisted in 222 patients. Significant improvement was observed regarding mHHS and VAS score in each group. We observed statistically significant difference regarding demarcation between the groups (P<.001). The higher rate of acetabular and femoral stem loosening was observed in the cemented (20.0%) and hybrid (18.9%) group. The lowest prosthesis survival rate after 16 years was observed in hybrid group (P<.001). CONCLUSION: Total hip replacement has good long-term clinical and functional outcomes. The lowest rate of prosthesis survival was observed in hybrid group with 84.2% after 16years.

Hip joint ligaments, a cadaver imaging study for education / Ligamentos de cadera, un estudio cadavérico imagenológico para educación

The stereoscopic morphology of the iliofemoral, pubofemoral, and ischiofemoral ligaments in hip joint is hard to understand, either in anatomy books or from cadaver dissection. To aid in understanding, three-dimensional models were built from the sectioned images of cadaver hip, which demonstrate fine components better than CTs and MRIs. In the female data of Visible Korean project, the ligaments and neighboring structures were recognized and outlined in detail. Successively, the outlines were stacked and reconstructed to manufacture their surface models by using the sophisticated computer method. The surface models were overlapped with the original sectioned images, which enhanced comprehension of the hip joint anatomy. With the surface models, hip joint was hyperextended to suggest the function of the ligaments. The graphic data of the surface reconstructed hip ligaments are expected to be the source of interactive simulators for anatomy and surgery of the hip joint.

La morfología estereoscópica de los ligamentos iliofemoral, pubofemoral e isquiofemoral de la articulación de la cadera es difícil de entender, ya sea a partir de lo hallado en los libros de anatomía como en la disección de cadáveres. Para ayudar en su comprensión, se construyeron modelos tridimensionales a partir de imágenes de secciones cadavéricas de la cadera, que demuestran de mejor manera los componentes finos, en comparación a las imágenes de tomografía axial computada y resonancia magnética nuclear. En los datos obtenidos del "Visible Korean Project", correspondientes a mujeres, los ligamentos de la articulación y sus estructuras vecinas fueron reconocidos y descritos en detalle. Sucesivamente, se identificaron los contornos y se reconstruyeron para la fabricación de modelos de superficie, mediante el uso de un sofisticado método informático. Los modelos de superficie se asociaron con las imágenes de sección originales, que aumentaron la comprensión de la anatomía de la articulación de la cadera. En los modelos de superficie se provocó la hipertensión de la articulación de la cadera para permitir evidenciar la función de los ligamentos. Se espera que los datos gráficos obtenidos de los modelos de superficie de los ligamentos de la cadera sirvan como fuente para el desarrollo de simuladores interactivos que permitan el estudio de la anatomía y la cirugía de la articulación de la cadera.

Comparación de esfuerzos pre y post quirúrgicos sobre articulación de cadera con secuelas de displasia / Comparison of pre- and postsurgical stress over a hip joint with dysplastic sequels

Introducción: la displasia residual de cadera en jóvenes y adultos requiere un procedimiento quirúrgico para su tratamiento; tener en cuenta el comportamiento biomecánico futuro de la articulación podría ser una útil herramienta en la planeación y evaluacióndel procedimiento quirúrgico más adecuado para el paciente. Objetivo: realizar una comparación entre la distribución de esfuerzos pre y post quirúrgicos sobre una articulación de cadera con secuelas de displasia utilizando el método de elementos finitos para su resolución. Métodos: se usó un modelo de elementos finitos de la articulación de un paciente con secuelas de displasia, reconstruido a partir de imágenes obtenidas por TAC, y un modelo de la reubicación articular simulando elprocedimiento quirúrgico realizado. El máximo esfuerzo generado y el área de soporte de peso fueron calculados durante la etapa de apoyo de un ciclo de marcha. Resultados: hay una excesiva carga sobre la articulación patológica debido a la reducida cobertura articular. Las simulaciones sobre el modelo post-quirúrgico revelaron una reducción del 20,20 % en elesfuerzo máximo generado sobre la cabeza femoral en el punto de mayor carga en la marcha (20 % de la fase de apoyo), además de una reducción del 49 % en la presión de contacto sobre el cartílago articular y un incremento del 64 % en el área de soporte de peso en el mismo punto. Conclusiones: este estudio revela una mejora biomecánica post-quirúrgica muy considerableen el nivel de la carga que soporta la articulación; por otra parte, permite tener un mayor acercamiento a la realidad del paciente y contribuye a la toma de una óptima decisión para el tratamiento de la patología.

Introduction: The treatment of residual hip dysplasia in young persons and adults requires surgery. Bearing in mind the future biomechanical behavior of the joint could be a useful tool in the planning and evaluation of the most appropriate surgical procedure. Objective: Compare the distribution of pre- and postsurgical stress over a hip joint with dysplastic sequels using the finite element method for its resolution. Methods: Use was made of a finite element model of a patient's hip joint with dysplastic sequels reconstructed from CT scan images, and a model of the joint relocation that simulated the surgical procedure performed. The maximum stress generated and the weight bearing area were estimated during the stance phase of the gait cycle. Results: The load on the treated joint is excessive due to the reduced joint coverage. Simulations on the postsurgical model showed a 20.20% reduction in the maximum stress exerted on the femoral head at the point of greatest load during the gait (20% of the stance phase), a 49% reduction in the contact pressure over the joint cartilage, and a 64% increase in the weight bearing area at the same point. Conclusions: The study revealed very considerable postsurgical biomechanical improvement in the amount of load borne by the joint. On the other hand, it allows a better view of the patient's reality and contributes to taking the best treatment decision.