[Translated article] Mechanical resistance of polylactic acid bone matrices developed by 3D printing for the reconstruction of bone defects.

INTRODUCTION: Bone defects are one of the main limitations in orthopaedic surgery and traumatology. For this reason, multiple bone replacement systems have been developed, either by prosthetic implant or by substitution with osteoforming substances, whose limitations are their survival and lack of structurality, respectively. The objective of this work is the generation of a new material for the creation of biologically active structures that have sufficient tensile strength to maintain the structure during remodelling. MATERIAL AND METHODS: A new filament based on the fusion of natural polylactide acid (PLA) powder was designed for the generation of pieces by means of fused deposition modelling (FDM) on which to carry out tensile mechanical tests of osteosynthesis material. A total of 13 groups with different cortical thickness, filling and layer height were carried out, with 10 tensile tests in each group, defining the tensile breaking limit for each group. The regression lines for each group and their mechanical resistance to traction on the filament used were determined. RESULTS: The filament ratio per contact surface unit with the osteosynthesis used was the main determinant of the mechanical resistance to traction, either at the expense of the increase in cortical thickness or by the increase in the percentage of cancellous bone filling. Layer height had a minor effect on tensile strength. The regression value was high for cortical thickness and cancellous filling, being elements with a predictable biomechanical behaviour. CONCLUSIONS: The new methodology allows the creation of personalised neutral and implantable PLA bone matrices for the reconstruction of large bone defects by means of 3D printing by FDM with a mechanical resistance to traction greater than that of current biological support structures.

Mechanical resistance of polylactic acid bone matrices developed by 3D printing for the reconstruction of bone defects. / Resistencia mecánica de matrices óseas de ácido poliláctico desarrolladas por impresión 3D para la reconstrucción de defectos óseos.

INTRODUCTION: Bone defects are one of the main limitations in orthopedic surgery and traumatology. For this reason, multiple bone replacement systems have been developed, either by prosthetic implant or by substitution with osteoforming substances, whose limitations are their survival and lack of structurality, respectively. The objective of this work is the generation of a new material for the creation of biologically active structures that have sufficient tensile strength to maintain the structure during remodeling. MATERIAL AND METHODS: A new filament based on the fusion of natural polylactide acid (PLA) powder was designed for the generation of pieces by means of fused deposition modeling (FDM) on which to carry out tensile mechanical tests of osteosynthesis material. A total of 13 groups with different cortical thickness, filling and layer height were carried out, with 10 tensile tests in each group, defining the tensile breaking limit for each group. The regression lines for each group and their mechanical resistance to traction on the filament used were determined. RESULTS: The filament ratio per contact surface unit with the osteosynthesis used was the main determinant of the mechanical resistance to traction, either at the expense of the increase in cortical thickness or by the increase in the percentage of cancellous bone filling. Layer height had a minor effect on tensile strength. The regression value was high for cortical thickness and cancellous filling, being elements with a predictable biomechanical behavior. CONCLUSIONS: The new methodology allows the creation of personalized neutral and implantable PLA bone matrices for the reconstruction of large bone defects by means of 3D printing by FDM with a mechanical resistance to traction greater than that of current biological support structures.

Un método 3D para estimar el efecto de osteotomías desrotadoras sobre alteraciones torsionales de fémur / A 3D method to estimate the effect of derotational osteotomies over femoral maltorsion

Introducción y objetivos: La medición precisa de la torsión femoral es esencial para el diagnóstico, indicación y planificación preoperatoria de las osteotomías desrotadoras femorales en pacientes con inestabilidad patelofemoral o dolor anterior de rodilla. Se han descrito múltiples métodos de medición, con valores muy diferentes entre ellos y ninguno de ellos permite establecer la magnitud de la osteotomía necesaria para devolver la torsión a valores normales. El objetivo del presente trabajo es desarrollar un método de medición que permita no solo el diagnóstico de pacientes con alteraciones torsionales, sino también establecer la magnitud de la osteotomía necesaria durante la cirugía. Material y métodos: Se seleccionaron 30 pacientes sin antecedentes de patología patelofemoral que disponían de una tomografía completa de miembros inferiores por otros motivos, siendo considerados así pacientes normales. Se calculó su torsión femoral mediante los métodos de Jeanmart y de Murphy por dos radiólogos independientes. Por otra parte, dos cirujanos ortopédicos independientes realizaron la medición de la torsión mediante el método 3D propuesto. Se evaluó el comportamiento normal de los datos y se definió la variabilidad intra- e interobservador del método 3D mediante su coeficiente de correlación intraclase y mediante el gráfico de Bland-Altman, realizando una comparación cuantitativa y cualitativa respectivamente con los métodos clásicos. Se estableció el intervalo de confianza de los valores normales con el nuevo método 3D y finalmente, se analizó al patrón de regresión lineal entre los métodos de Jeanmart y Murphy con el método de medición 3D. Resultados: La media de torsión femoral con el método 3D fue de 12,74° (DE 5,96°, IC 95%: 11,67 a 13,82°). Con el método de Jeanmart, esta fue de 12,84° (DE 8,60°, IC 95%: 11,28 a 14,39°) y de 15,87° (DE 10,68°, IC 95%: 13,94 a 17,80°) con el método de Murphy.(AU)

Introduction and objectives: Accurate measurement of femoral torsion is essential to diagnosing, correct surgical decision-making, and the preoperative planning of derotational osteotomies in a subgroup of anterior knee pain patients and patellofemoral instability. Several measurement techniques have been described with great variability in the magnitude of the values. Moreover, none of them can predict the effect of rotational osteotomy on the femoral version value. The purpose of the present work is to develop a method to reliably measure femoral torsion as well as to evaluate the effects of osteotomy on the femoral version angle. Material and methods: 30 patients without previous signs neither symptoms of patellofemoral pain or patellofemoral instability and with a lower limbs CT were selected. Their femoral torsion was measured using the classic Jeanmart and the Murphy's method by two independent radiologists. Independently, two orthopedic surgeons measured femoral torsion with the 3D method described in this study. The intraclass coefficient correlation and the Bland–Altman tests were used to analyze qualitatively and quantitatively the intraobserver and interobserver variability of the method regarding the Jeanmart's and Murphy's method. The confidence interval of the Normal values of the new method were defined and a lineal regression analysis between the 3D-Jeanmart's and 3D-Muphy's methods was performed. Results: The mean femoral version with the 3D method was 12.74° (SD 5.96°, 95% CI: 11.67° to 13.82°). With Jeanmart's method, it was 12.84° (SD 8.60°, 95% CI: 11.28° to 14.39°) and 15.87° (SD 10.68°, 95% CI: 13.94° to 17.80°) with Murphy's method, being these differences not statistically significant. Both interobserver and intraobserver agreement of the 3D method were high.(AU)

[Translated article] A 3D method to estimate the effect of derotational osteotomies over femoral maltorsion / Un método 3D para estimar el efecto de osteotomías desrotadoras sobre alteraciones torsionales de fémur

Introducción y objetivos: La medición precisa de la torsión femoral es esencial para el diagnóstico, indicación y planificación preoperatoria de las osteotomías desrotadoras femorales en pacientes con inestabilidad patelofemoral o dolor anterior de rodilla. Se han descrito múltiples métodos de medición, con valores muy diferentes entre ellos y ninguno de ellos permite establecer la magnitud de la osteotomía necesaria para devolver la torsión a valores normales. El objetivo del presente trabajo es desarrollar un método de medición que permita no solo el diagnóstico de pacientes con alteraciones torsionales, sino también establecer la magnitud de la osteotomía necesaria durante la cirugía. Material y métodos: Se seleccionaron 30 pacientes sin antecedentes de patología patelofemoral que disponían de una tomografía completa de miembros inferiores por otros motivos, siendo considerados así pacientes normales. Se calculó su torsión femoral mediante los métodos de Jeanmart y de Murphy por dos radiólogos independientes. Por otra parte, dos cirujanos ortopédicos independientes realizaron la medición de la torsión mediante el método 3D propuesto. Se evaluó el comportamiento normal de los datos y se definió la variabilidad intra- e interobservador del método 3D mediante su coeficiente de correlación intraclase y mediante el gráfico de Bland-Altman, realizando una comparación cuantitativa y cualitativa respectivamente con los métodos clásicos. Se estableció el intervalo de confianza de los valores normales con el nuevo método 3D y finalmente, se analizó al patrón de regresión lineal entre los métodos de Jeanmart y Murphy con el método de medición 3D. Resultados: La media de torsión femoral con el método 3D fue de 12,74° (DE 5,96°, IC 95%: 11,67 a 13,82°). Con el método de Jeanmart, esta fue de 12,84° (DE 8,60°, IC 95%: 11,28 a 14,39°) y de 15,87° (DE 10,68°, IC 95%: 13,94 a 17,80°) con el método de Murphy.(AU)

Introduction and objectives: Accurate measurement of femoral torsion is essential to diagnosing, correct surgical decision-making, and the preoperative planning of derotational osteotomies in a subgroup of anterior knee pain patients and patellofemoral instability. Several measurement techniques have been described with great variability in the magnitude of the values. Moreover, none of them can predict the effect of rotational osteotomy on the femoral version value. The purpose of the present work is to develop a method to reliably measure femoral torsion as well as to evaluate the effects of osteotomy on the femoral version angle. Material and methods: 30 patients without previous signs neither symptoms of patellofemoral pain or patellofemoral instability and with a lower limbs CT were selected. Their femoral torsion was measured using the classic Jeanmart and the Murphy's method by two independent radiologists. Independently, two orthopedic surgeons measured femoral torsion with the 3D method described in this study. The intraclass coefficient correlation and the Bland–Altman tests were used to analyze qualitatively and quantitatively the intraobserver and interobserver variability of the method regarding the Jeanmart's and Murphy's method. The confidence interval of the Normal values of the new method were defined and a lineal regression analysis between the 3D-Jeanmart's and 3D-Muphy's methods was performed. Results: The mean femoral version with the 3D method was 12.74° (SD 5.96°, 95% CI: 11.67° to 13.82°). With Jeanmart's method, it was 12.84° (SD 8.60°, 95% CI: 11.28° to 14.39°) and 15.87° (SD 10.68°, 95% CI: 13.94° to 17.80°) with Murphy's method, being these differences not statistically significant. Both interobserver and intraobserver agreement of the 3D method were high.(AU)

[Translated article] A 3D method to estimate the effect of derotational osteotomies over femoral maltorsion.

INTRODUCTION AND OBJECTIVES: Accurate measurement of femoral torsion is essential to diagnosing, correct surgical decision-making, and the preoperative planning of derotational osteotomies in a subgroup of anterior knee pain patients and patellofemoral instability. Several measurement techniques have been described with great variability in the magnitude of the values. Moreover, none of them can predict the effect of rotational osteotomy on the femoral version value. The purpose of the present work is to develop a method to reliably measure femoral torsion as well as to evaluate the effects of osteotomy on the femoral version angle. MATERIAL AND METHODS: 30 patients without previous signs neither symptoms of patellofemoral pain or patellofemoral instability and with a lower limbs CT were selected. Their femoral torsion was measured using the classic Jeanmart and the Murphy's method by two independent radiologists. Independently, two orthopedic surgeons measured femoral torsion with the 3D method described in this study. The intraclass coefficient correlation and the Bland-Altman tests were used to analyze qualitatively and quantitatively the intraobserver and interobserver variability of the method regarding the Jeanmart's and Murphy's method. The confidence interval of the Normal values of the new method were defined and a lineal regression analysis between the 3D-Jeanmart's and 3D-Muphy's methods was performed. RESULTS: The mean femoral version with the 3D method was 12.74° (SD 5.96°, 95% CI: 11.67°-13.82°). With Jeanmart's method, it was 12.84° (SD 8.60°, 95% CI: 11.28°-14.39°) and 15.87° (SD 10.68°, 95% CI: 13.94°-17.80°) with Murphy's method, being these differences not statistically significant. Both interobserver and intraobserver agreement of the 3D method were high. CONCLUSION: The method presented in this study allows for the reliable quantification of femoral torsion in a reproducible way. This method can be applied in several open access 3D image programmes what makes its implementation in the healthcare centres possible from now on.

A novel arthroscopy training program based on a 3D printed simulator.

Background: Arthroscopy is the most important and exciting contribution to sports medicine of the last 100 years. One of its main limitations, however, is the steep learning curve it requires, which is not easy to beat given the scarcity and the high price of arthroscopy simulators. Hypothesis/purpose: To describe and evaluate the effectiveness of an open-access arthroscopy training program based on a 3D-printed simulator. Methods: A model was designed, which was to be printed on a fused filament fabrication (FFF) 3D printer for home use with polylactic acid (PLA) filaments. Fourteen exercises were prepared, each with its timeframe and conceptual goals, arranged from least difficult to most challenging. Exercises were designed to assist subjects in developing the skills of an experienced arthroscopic surgeon through use of the simulator. Twenty subjects from nine hospitals completed the arthroscopy training program. Performance in each exercise was evaluated according to the Arthroscopic Surgical Skill Evaluation Tool (ASSET), taking into account the number of times a student had to repeat each exercise to complete it successfully. Results: The mean ASSET score for each exercise was 22 points (IQR 19-25) and the mean number of times students had to repeat each exercise was 16 (95% CI 15.27-17.97). Eighty-five percent of subjects completed the program. The device was printed without difficulty by an independent investigator without prior knowledge of 3D printing. The price of the device was under US$ 12. Conclusion: Subjects exhibited an improvement in their basic arthroscopic skills on the simulator. The number of times each of them had to repeat each exercise was similar, which is indicative of a smooth progression of difficulty along the program. The device proved easy to print, accessible, economical, and effective. This is the first structured program based on an open-access arthroscopic simulator to obtain satisfactory results.

A 3D method to estimate the effect of derotational osteotomies over femoral maltorsion. / Un método 3D para estimar el efecto de osteotomías desrotadoras sobre alteraciones torsionales de fémur.

INTRODUCTION AND OBJECTIVES: Accurate measurement of femoral torsion is essential to diagnosing, correct surgical decision-making, and the preoperative planning of derotational osteotomies in a subgroup of anterior knee pain patients and patellofemoral instability. Several measurement techniques have been described with great variability in the magnitude of the values. Moreover, none of them can predict the effect of rotational osteotomy on the femoral version value. The purpose of the present work is to develop a method to reliably measure femoral torsion as well as to evaluate the effects of osteotomy on the femoral version angle. MATERIAL AND METHODS: 30 patients without previous signs neither symptoms of patellofemoral pain or patellofemoral instability and with a lower limbs CT were selected. Their femoral torsion was measured using the classic Jeanmart and the Murphy's method by two independent radiologists. Independently, two orthopedic surgeons measured femoral torsion with the 3D method described in this study. The intraclass coefficient correlation and the Bland-Altman tests were used to analyze qualitatively and quantitatively the intraobserver and interobserver variability of the method regarding the Jeanmart's and Murphy's method. The confidence interval of the Normal values of the new method were defined and a lineal regression analysis between the 3D-Jeanmart's and 3D-Muphy's methods was performed. RESULTS: The mean femoral version with the 3D method was 12.74° (SD 5.96°, 95% CI: 11.67° to 13.82°). With Jeanmart's method, it was 12.84° (SD 8.60°, 95% CI: 11.28° to 14.39°) and 15.87° (SD 10.68°, 95% CI: 13.94° to 17.80°) with Murphy's method, being these differences not statistically significant. Both interobserver and intraobserver agreement of the 3D method were high. CONCLUSION: The method presented in this study allows for the reliable quantification of femoral torsion in a reproducible way. This method can be applied in several open access 3D image programs what makes its implementation in the healthcare centers possible from now on.

[Effect of asymptomatic chodral on the recovery of the working patient after a traumatic injury of the knee]. / Efecto de las lesiones condrales asintomáticas en la recuperación del paciente laboral tras una lesión traumática de rodilla.

The objective of this study was to investigate the prevalence and epidemiology of knee cartilage lesions in the work environment, and to assess whether they increase the patient's work leave and thus also cost. We also analyzed the prevalence of concomitant pathology and how it affected recovery and final outcome. MATERIAL AND METHODS: Monocentric retrospective cohort of patients with occupational injuries who underwent knee arthroscopy during 2018. Demographic data, diagnosis, concomitant chondral pathology, treatment, symptoms and signs at discharge, work leave and total cost were collected. RESULTS: 123 patients were analyzed, with a mean age of 47 years. No differences were found between sexes or with respect to obesity. Asymptomatic chondral lesions were found in 35.25% of the patients, primarily the older ones (48-53 years). The presence of cartilaginous pathology did not increase days of work leave or total cost (p > 0.05). In patients with meniscopathy in whom meniscectomy is performed, the chondral lesion increased the number of days of work leave (p = 0.03). There were no differences in the number of days of work leave nor total cost for different treatments of chondral pathology. CONCLUSION: The management of a concomitant chondral knee lesion is still controversial. These lesions might convey poorer functional prognosis in patients with meniscopathy. Current therapies have not shown a clear benefit in work injuries.

El objetivo principal del estudio fue analizar la asociación entre la presencia de lesiones cartilaginosas asintomáticas en pacientes con lesiones traumáticas de rodilla y su tiempo de baja y gasto mutual. Los objetivos secundarios fueron describir la prevalencia y epidemiología de estas lesiones y analizar si se asocian con la presencia de obesidad y un peor resultado final. Material y métodos: Revisión retrospectiva de una cohorte de todos los pacientes a los que se les realizó una artroscopía de rodilla tras una lesión traumática en un centro mutual en el año 2018. Se recogieron datos demográficos, diagnóstico, patología condral concomitante, tratamiento, clínica al alta, tiempo total de baja y el gasto derivado de ésta. Resultados: Fueron analizados 123 pacientes con una media de edad de 47 años, no se encontraron diferencias entre sexos ni respecto a la obesidad entre los grupos con y sin lesión condral. Las lesiones cartilaginosas fueron diagnosticadas en más de un tercio de los pacientes valorados (35.25%), la mayoría entre 48 y 53 años. La presencia de patología condral no fue un condicionante que aumentara los días de baja o el gasto total (p > 0.05). En pacientes con meniscectomía, la lesión condral aumenta el tiempo de baja (p = 0.03). Los tratamientos enfocados en la lesión condral no produjeron diferencias en cuanto a la duración de la baja ni en el gasto. Conclusión: El manejo de una lesión condral concomitante a nivel de la rodilla sigue presentando controversia. Podría implicar un factor de mal pronóstico de recuperación en pacientes con meniscopatía y las terapias actuales no han mostrado un beneficio claro en estos pacientes del entorno laboral.

Efecto de las lesiones condrales asintomáticas en la recuperación del paciente laboral tras una lesión traumática de rodilla / Effect of asymptomatic chodral on the recovery of the working patient after a traumatic injury of the knee

Resumen: El objetivo principal del estudio fue analizar la asociación entre la presencia de lesiones cartilaginosas asintomáticas en pacientes con lesiones traumáticas de rodilla y su tiempo de baja y gasto mutual. Los objetivos secundarios fueron describir la prevalencia y epidemiología de estas lesiones y analizar si se asocian con la presencia de obesidad y un peor resultado final. Material y métodos: Revisión retrospectiva de una cohorte de todos los pacientes a los que se les realizó una artroscopía de rodilla tras una lesión traumática en un centro mutual en el año 2018. Se recogieron datos demográficos, diagnóstico, patología condral concomitante, tratamiento, clínica al alta, tiempo total de baja y el gasto derivado de ésta. Resultados: Fueron analizados 123 pacientes con una media de edad de 47 años, no se encontraron diferencias entre sexos ni respecto a la obesidad entre los grupos con y sin lesión condral. Las lesiones cartilaginosas fueron diagnosticadas en más de un tercio de los pacientes valorados (35.25%), la mayoría entre 48 y 53 años. La presencia de patología condral no fue un condicionante que aumentara los días de baja o el gasto total (p > 0.05). En pacientes con meniscectomía, la lesión condral aumenta el tiempo de baja (p = 0.03). Los tratamientos enfocados en la lesión condral no produjeron diferencias en cuanto a la duración de la baja ni en el gasto. Conclusión: El manejo de una lesión condral concomitante a nivel de la rodilla sigue presentando controversia. Podría implicar un factor de mal pronóstico de recuperación en pacientes con meniscopatía y las terapias actuales no han mostrado un beneficio claro en estos pacientes del entorno laboral.

Abstract: The objective of this study was to investigate the prevalence and epidemiology of knee cartilage lesions in the work environment, and to assess whether they increase the patient's work leave and thus also cost. We also analyzed the prevalence of concomitant pathology and how it affected recovery and final outcome. Material and methods: Monocentric retrospective cohort of patients with occupational injuries who underwent knee arthroscopy during 2018. Demographic data, diagnosis, concomitant chondral pathology, treatment, symptoms and signs at discharge, work leave and total cost were collected. Results: 123 patients were analyzed, with a mean age of 47 years. No differences were found between sexes or with respect to obesity. Asymptomatic chondral lesions were found in 35.25% of the patients, primarily the older ones (48-53 years). The presence of cartilaginous pathology did not increase days of work leave or total cost (p > 0.05). In patients with meniscopathy in whom meniscectomy is performed, the chondral lesion increased the number of days of work leave (p = 0.03). There were no differences in the number of days of work leave nor total cost for different treatments of chondral pathology. Conclusion: The management of a concomitant chondral knee lesion is still controversial. These lesions might convey poorer functional prognosis in patients with meniscopathy. Current therapies have not shown a clear benefit in work injuries.

Implantes intramedulares enterrados para fracturas de antebrazo pediátricas. ¿Mejora la tasa de refracturas? / Buried intramedullary implants for paediatric forearm fractures. Does the refracture rate improve?

INTRODUCCIÓN: Las fracturas inestables de antebrazo pueden requerir un manejo quirúrgico mediante reducción y osteosíntesis con agujas intramedulares. Esta fijación debe retirarse precozmente si se ha dejado expuesta, pero esto podría aumentar el riesgo de refracturas sobre un hueso en periodo de remodelado. Como alternativa podemos mantener durante más tiempo las agujas, enterradas a nivel subcutáneo, para proteger el callo óseo. OBJETIVO: Valorar si hay diferencias entre utilizar agujas expuestas respecto a enterrarlas en pacientes pediátricos con fracturas de antebrazo. Nuestra hipótesis es que al enterrar las agujas las mantenemos más tiempo reduciendo las refracturas de antebrazo. MATERIAL Y MÉTODOS: Presentamos una cohorte de 75 pacientes pediátricos con fractura de antebrazo entre 2010 y 2016. Se recogieron datos demográficos, técnica quirúrgica, complicaciones y seguimiento del paciente. RESULTADOS: Los implantes se dejaron expuestos en 50 pacientes y 25 de forma enterrada. El tiempo medio de retirada de los implantes expuestos fue de 6,8 semanas, y de 17,6semanas en los enterrados. No se hallaron diferencias significativas en cuanto a consolidación (p = 0,19) ni en tiempo de inmovilización (p = 0,22). Respecto a las refracturas, se observa un mayor número en el grupo de la osteosíntesis expuesta (4pacientes) respecto a solo un caso con osteosíntesis enterrada, pero sin llegar a presentar diferencias significativas (p = 0,49). No se detectaron complicaciones posquirúrgicas y la funcionalidad fue excelente al final del seguimiento en ambos grupos. CONCLUSIÓN: Dejar los implantes enterrados respecto a expuestos a piel no condiciona una disminución en el número de refracturas ni otras complicaciones, con una adecuada funcionalidad del paciente en ambos casos

INTRODUCTION: Unstable forearm fractures may require surgical management by reduction and osteosynthesis with intramedullary needles. This fixation should be removed early if it has been left exposed, but this could increase the risk of refracture in a bone in the period of remodelling. As an alternative we can keep the needles, buried subcutaneously, for a longer time, to protect the bone callus. OBJECTIVE: To assess whether there are differences between using exposed needles with respect to burying them in paediatric patients with forearm fractures. Our hypothesis is that by burying the needles we keep them longer by reducing forearm refractures. MATERIAL AND METHODS: We present a cohort of 75 paediatric patients with a forearm fracture between 2010 and 2016. Demographic data, surgical technique, complications and patient follow-up were collected. RESULTS: The implants were left exposed in 50 patients and 25 buried. The average time of removal of the exposed implants was 6.8 weeks and 17.6weeks in the buried ones. No significant differences were found in terms of consolidation (P=.19) or immobilization time (P=.22). Regarding refractures, a greater number was observed in the exposed osteosynthesis group (4patients) compared to only one case with buried osteosynthesis, but there were no significant differences (P=.49). No postsurgical complications were detected and the functionality was excellent at the end of the follow-up in both groups. CONCLUSION: Leaving implants buried in relation to skin exposed does not cause a decrease in the number of refractures or other complications, with adequate patient functionality in both cases

Buried intramedullary implants for paediatric forearm fractures. Does the refracture rate improve? / Implantes intramedulares enterrados para fracturas de antebrazo pediátricas. ¿Mejora la tasa de refracturas?

INTRODUCTION: Unstable forearm fractures may require surgical management by reduction and osteosynthesis with intramedullary needles. This fixation should be removed early if it has been left exposed, but this could increase the risk of refracture in a bone in the period of remodelling. As an alternative we can keep the needles, buried subcutaneously, for a longer time, to protect the bone callus. OBJECTIVE: To assess whether there are differences between using exposed needles with respect to burying them in paediatric patients with forearm fractures. Our hypothesis is that by burying the needles we keep them longer by reducing forearm refractures. MATERIAL AND METHODS: We present a cohort of 75 paediatric patients with a forearm fracture between 2010 and 2016. Demographic data, surgical technique, complications and patient follow-up were collected. RESULTS: The implants were left exposed in 50 patients and 25 buried. The average time of removal of the exposed implants was 6.8weeks and 17.6weeks in the buried ones. No significant differences were found in terms of consolidation (P=.19) or immobilization time (P=.22). Regarding refractures, a greater number was observed in the exposed osteosynthesis group (4patients) compared to only one case with buried osteosynthesis, but there were no significant differences (P=.49). No postsurgical complications were detected and the functionality was excellent at the end of the follow-up in both groups. CONCLUSION: Leaving implants buried in relation to skin exposed does not cause a decrease in the number of refractures or other complications, with adequate patient functionality in both cases.

El valor c como aproximación entre la clínica y la significación estadísticamente significativa / The c-value as an approach between the clinical and statistical signification

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