Implementation of an enhanced recovery after surgery program including a patient school: Impact on quality of life results.

INTRODUCTION: Enhanced Recovery After Surgery (ERAS) protocols and educational programmes have been shown to accelerate orthopaedic surgery recovery with fewer complications, and improve patient-reported outcomes (PROs) for different types of surgery. The objective was to evaluate the impact of an ERAS programme including a patient school on health outcomes and PROs for Total Knee Replacement (TKR) surgery. MATERIAL AND METHODS: A multidisciplinary group created the programme and the patient school (preoperative consultations where the patients' surgical processes are explained and are also given instructions for an appropriate perioperative care management). An observational, prospective study was conducted on all patients operated for TKR from March 2021 to March 2022. Main health outcomes were: hospital stay length, surgical complications and surgery cancellations due to a wrong preoperative medication management. PROs evaluated were: patient satisfaction with pain management, the school, and quality of life before and after surgery (EQ-5D). RESULTS: One hundred thirty-three patients were included. Median hospital stay length was 3 days (IQR 3-5). Rate of surgical complications was 25.6%. No surgery was cancelled. Patient satisfaction rates with pain management and with the school were 8.10/10 and 9.89/10, respectively. Concerning quality of life, mean improvement in mobility and knee pain after the surgery was 0.66 (p < 0.05) and 0.84 (p < 0.05), respectively. CONCLUSIONS: The ERAS programme including a patient school was highly successful with a fast recovery, a short hospital stay length, no surgery cancellations, and improved PROs.

Cultivo condral in vitro bajo estímulos de compresión y cizallamiento. De las células troncales mesenquimales al cartílago hialino / In vitro chondral culture under compression and shear stimuli. From mesenchymal stem cells to hyaline cartilage

INTRODUCCIÓN: La creación in vitro de cartílago hialino articular supone un reto, ya que, a día de hoy, no se ha conseguido la síntesis ex vivo de un tejido estructurado con las mismas propiedades biomecánicas e histológicas del cartílago articular. Para simular las condiciones fisiológicas hemos diseñado un sistema de cultivo in vitro que reproduce el movimiento articular. MATERIAL Y MÉTODO: Hemos desarrollado un biorreactor de cultivo celular que imprime un estímulo mecánico sobre una matriz de elastina en la que están embebidas células troncales mesenquimales (MSC). La primera fase de estudio corresponde al desarrollo de un biorreactor para cultivo de cartílago hialino y la comprobación de la viabilidad celular en la matriz de elastina en ausencia de estímulo. La segunda fase del estudio engloba el cultivo de MSC bajo estímulo mecánico y el análisis del tejido resultante. RESULTADOS: Tras el cultivo bajo estímulo mecánico no obtuvimos tejido hialino por falta de celularidad y desestructuración de la matriz. CONCLUSIÓN: El patrón de estímulo utilizado no ha resultado efectivo para la generación de cartílago hialino, por lo que se deberán explorar otras combinaciones en futuras investigaciones

INTRODUCTION: The in vitro creation of hyaline joint cartilage is a challenge since, to date, the ex vivo synthesis of a structured tissue with the same biomechanical and histological properties of the joint cartilage has not been achieved. To simulate the physiological conditions we have designed an in vitro culture system that reproduces joint movement. MATERIAL AND METHOD: We have developed a cell culture bioreactor that prints a mechanical stimulus on an elastin matrix, in which mesenchymal stem cells (MSC) are embedded. The first phase of study corresponds to the development of a bioreactor for hyaline cartilage culture and the verification of cell viability in the elastin matrix in the absence of stimulus. The second phase of the study includes the MSC culture under mechanical stimulus and the analysis of the resulting tissue. RESULTS: After culture under mechanical stimulation we did not obtain hyaline tissue due to lack of cellularity and matrix destructuring. CONCLUSION: The stimulus pattern used has not been effective in generating hyaline cartilage, so other combinations should be explored in future research

In vitro chondral culture under compression and shear stimuli. From mesenchymal stem cells to hyaline cartilage. / Cultivo condral in vitro bajo estímulos de compresión y cizallamiento. De las células troncales mesenquimales al cartílago hialino.

INTRODUCTION: The in vitro creation of hyaline joint cartilage is a challenge since, to date, the ex vivo synthesis of a structured tissue with the same biomechanical and histological properties of the joint cartilage has not been achieved. To simulate the physiological conditions we have designed an in vitro culture system that reproduces joint movement. MATERIAL AND METHOD: We have developed a cell culture bioreactor that prints a mechanical stimulus on an elastin matrix, in which mesenchymal stem cells (MSC) are embedded. The first phase of study corresponds to the development of a bioreactor for hyaline cartilage culture and the verification of cell viability in the elastin matrix in the absence of stimulus. The second phase of the study includes the MSC culture under mechanical stimulus and the analysis of the resulting tissue. RESULTS: After culture under mechanical stimulation we did not obtain hyaline tissue due to lack of cellularity and matrix destructuring. CONCLUSION: The stimulus pattern used has not been effective in generating hyaline cartilage, so other combinations should be explored in future research.

Espaciador femoral total biarticulado para el tratamiento de la infección periprotésica de cadera y rodilla con pérdida completa de hueso. Modificación técnica / Biarticular total femoral spacer for complete bone loss in periprosthetic joint infection. A technical modification

Antecedentes: El manejo de los defectos óseos completos secundarios a una infección periprotésica a nivel de la cadera y/o rodilla continúa siendo un auténtico reto quirúrgico. Material y métodos: Presentamos una modificación técnica para la realización de un espaciador femoral biarticulado con un enclavado femoral, sin necesidad de abordar la tibia proximal, ya sea para obtener la fijación del espaciador o la articulación del mismo. Resultados: Se han intervenido 3 pacientes mediante esta técnica, no existiendo ninguna complicación intraoperatoria, resolviéndose la infección y mejorando la función previa en todos ellos, volviendo a deambular con diferentes ayudas. Conclusiones: Esta modificación técnica es una alternativa en aquellos casos donde es preciso resecar el fémur completo pero no es necesario abordar la tibia

Background: The management of complete bone defects in hip and knee periprosthetic infection is still a real surgical challenge. Material and methods: We present a technical modification for performing a biarticular total femoral spacer with a femoral nail without the need to approach the proximal tibia. Results: Three patients were operated with this technique. There was no intraoperative complication. The infection was resolved in all patients operated at final follow-up. All patients improved their previous functional situation and could walk with different aids. Conclusions: This technical modification is an alternative for cases where it is necessary to resect the complete femur, but it is not necessary to approach the tibia

Biarticular total femoral spacer for complete bone loss in periprosthetic joint infection. A technical modification. / Espaciador femoral total biarticulado para el tratamiento de la infección periprotésica de cadera y rodilla con pérdida completa de hueso. Modificación técnica.

BACKGROUND: The management of complete bone defects in hip and knee periprosthetic infection is still a real surgical challenge. MATERIAL AND METHODS: We present a technical modification for performing a biarticular total femoral spacer with a femoral nail without the need to approach the proximal tibia. RESULTS: Three patients were operated with this technique. There was no intraoperative complication. The infection was resolved in all patients operated at final follow-up. All patients improved their previous functional situation and could walk with different aids. CONCLUSIONS: This technical modification is an alternative for cases where it is necessary to resect the complete femur, but it is not necessary to approach the tibia.

Nuevo método de liberación de antibióticos del cemento óseo (polimetilmetacrilato): redefiniendo los límites / New method for antibiotic release from bone cement (polymethylmethacrylate): redefining boundaries

Introducción. La creciente resistencia a antimicrobianos está impulsando la adición de antibióticos con elevada actividad antiestafilocócica al polimetilmetacrilato (PMMA), para su uso en los espaciadores de cemento en la infección periprotésica. El linezolid o el levofloxacino ya han sido utilizados en estudios in vitro; sin embargo, la rifampicina ha demostrado un efecto deletéreo sobre las propiedades mecánicas del PMMA, inhibiendo su polimerización. El objetivo de nuestro estudio fue aislar la rifampicina durante el proceso de polimerización mediante técnicas de microencapsulación, con el fin de obtener un PMMA apto para la fabricación de espaciadores articulares. Material y método. Se sintetizaron microcápsulas de rifampicina con alginato y PHBV, utilizando Rifaldin®. Se estudió la concentración de rifampicina mediante espectrofotometría UV-visible. Se realizaron ensayos de compresión, dureza y tiempo de fraguado con probetas de cemento CMW®1 solo, con rifampicina y microcápsulas de PHBV y alginato. Resultados. El rendimiento de producción, la eficiencia y el rendimiento de microencapsulación fueron mayores con alginato (p=0,0001). El cemento con microcápsulas mostró mayor resistencia a la compresión que el cemento con rifampicina (91,26±5,13, 91,35±6,29 y 74,04±3,57MPa en alginato, PHBV y rifampicina, respectivamente) (p=0,0001). El tiempo de fraguado disminuyó, siendo la curva de dureza del cemento con microcápsulas de alginato similar a la de control. Discusión y conclusiones. La microencapsulación con alginato es una técnica adecuada para introducir rifampicina en el PMMA preservando las propiedades de compresión y el tiempo de fraguado. Su obtención permitiría fabricar espaciadores que liberasen localmente rifampicina para el tratamiento de la infección periprotésica (AU)

Introduction. The increasing antimicrobial resistance is promoting the addition of antibiotics with high antistaphylococcal activity to polymethylmethacrylate (PMMA), for use in cement spacers in periprosthetic joint infection. Linezolid and levofloxacin have already been used in in-vitro studies, however, rifampicin has been shown to have a deleterious effect on the mechanical properties of PMMA, because it inhibits PMMA polymerization. The objective of our study was to isolate the rifampicin during the polymerization process using microencapsulation techniques, in order to obtain a PMMA suitable for manufacturing bone cement spacers. Material and method. Microcapsules of rifampicin were synthesized with alginate and PHBV, using Rifaldin®. The concentration levels of rifampicin were studied by UV-visible spectrophotometry. Compression, hardness and setting time tests were performed with CMW®1 cement samples alone, with non-encapsulated rifampicin and with alginate or PHBV microcapsules. Results. The production yield, efficiency and microencapsulation yield were greater with alginate (P = .0001). The cement with microcapsules demonstrated greater resistance to compression than the cement with rifampicin (91.26±5.13, 91.35±6.29 and 74.04±3.57 MPa in alginate, PHBV and rifampicin, respectively) (P = .0001). The setting time reduced, and the hardness curve of the cement with alginate microcapsules was similar to that of the control. Discussion and conclusions. Microencapsulation with alginate is an appropriate technique for introducing rifampicin into PMMA, preserving compression properties and setting time. This could allow intraoperative manufacturing of bone cement spacers that release rifampicin for the treatment of periprosthetic joint infection (AU)

New method for antibiotic release from bone cement (polymethylmethacrylate): Redefining boundaries. / Nuevo método de liberación de antibióticos del cemento óseo (polimetilmetacrilato): redefiniendo los límites.

INTRODUCTION: The increasing antimicrobial resistance is promoting the addition of antibiotics with high antistaphylococcal activity to polymethylmethacrylate (PMMA), for use in cement spacers in periprosthetic joint infection. Linezolid and levofloxacin have already been used in in-vitro studies, however, rifampicin has been shown to have a deleterious effect on the mechanical properties of PMMA, because it inhibits PMMA polymerization. The objective of our study was to isolate the rifampicin during the polymerization process using microencapsulation techniques, in order to obtain a PMMA suitable for manufacturing bone cement spacers. MATERIAL AND METHOD: Microcapsules of rifampicin were synthesized with alginate and PHBV, using Rifaldin®. The concentration levels of rifampicin were studied by UV-visible spectrophotometry. Compression, hardness and setting time tests were performed with CMW®1 cement samples alone, with non-encapsulated rifampicin and with alginate or PHBV microcapsules. RESULTS: The production yield, efficiency and microencapsulation yield were greater with alginate (P = .0001). The cement with microcapsules demonstrated greater resistance to compression than the cement with rifampicin (91.26±5.13, 91.35±6.29 and 74.04±3.57 MPa in alginate, PHBV and rifampicin, respectively) (P = .0001). The setting time reduced, and the hardness curve of the cement with alginate microcapsules was similar to that of the control. DISCUSSION AND CONCLUSIONS: Microencapsulation with alginate is an appropriate technique for introducing rifampicin into PMMA, preserving compression properties and setting time. This could allow intraoperative manufacturing of bone cement spacers that release rifampicin for the treatment of periprosthetic joint infection.

Hemipelvectomías tras sarcomas de localización pélvica de alto grado: pronóstico en condrosarcomas frente a otros tipos histológicos / Hemipelvectomy for the treatment of high-grade sarcomas: Pronostic of chondrosarcomas compared to other histological types

Introducción. La baja incidencia y la heterogeneidad histológica de los sarcomas pélvicos primarios dificulta el análisis y publicación de cohortes homogéneas. Objetivo. Describir el pronóstico vital y funcional dependiendo del tipo histológico en una serie de sarcomas primarios de localización pélvica de alto grado localmente avanzados tratados mediante hemipelvectomía. Material y métodos. Estudio descriptivo, epidemiológico y funcional de 15 casos tratados entre 2006-2012. Se realizó análisis de supervivencia, valoración funcional y estudio comparativo en función del tipo histológico, comparando los condrosarcomas frente al resto de diagnósticos histológicos. Resultados. El tipo histológico más frecuente en la serie fue el condrosarcoma (46%), y la localización más frecuente la zona P2 (periacetabular) (73%). Se realizó una hemipelvectomía interna en el 66% de los casos, siendo mayor (83%) en el caso de los condrosarcomas. La supervivencia global a los 2 años fue del 54%, siendo más elevada en el grupo condrosarcoma (67%) que en el resto (43%). La situación funcional dependió del tipo de intervención, sin encontrar diferencias en función del tipo histológico ni de la realización de reconstrucción. Discusión y conclusiones. La hemipelvectomía como procedimiento quirúrgico está indicada para el tratamiento de los sarcomas primarios de localización pélvica de alto grado localmente avanzados independientemente del tipo histológico. La incidencia de conservación del miembro y la supervivencia global es mayor en los condrosarcomas frente al resto de tipos histológicos (AU)

Introduction. The low incidence and histological heterogeneity of primary sarcomas located in the pelvis makes it difficult to find homogeneous cohorts. Objective. To describe the life and functional prognosis depending on the histological type of sarcoma in a series of locally advanced high-grade pelvis located sarcomas treated by hemipelvectomy. Methods. A descriptive epidemiological and functional study was conducted on 15 cases treated between 2006 and 2012. Survival analysis, functional assessment, and a comparative study by histological type were performed, comparing chondrosarcomas to other histological diagnoses. Results. The most frequent histological type was chondrosarcoma (46%), and the most frequent location was P2 (periacetabular) (73%). An internal hemipelvectomy was performed in 66% of cases, with a higher incidence (83%) in chondrosarcomas. Overall two-year survival was 54%, with higher survival in the chondrosarcoma group (67%) than in the other sarcomas (43%). Functional status depended on the type of intervention, with no differences in histological type or the performance of the reconstruction. Discussion and conclusions. Hemipelvectomy is a surgical procedure that is indicated for the treatment of locally advanced high grade pelvis located sarcomas, regardless of histological type. The incidence of limb preservation and overall survival is higher in chondrosarcomas compared to other sarcomas (AU)

[Hemipelvectomy for the treatment of high-grade sarcomas: Pronostic of chondrosarcomas compared to other histological types]. / Hemipelvectomías tras sarcomas de localización pélvica de alto grado: pronóstico en condrosarcomas frente a otros tipos histológicos.

INTRODUCTION: The low incidence and histological heterogeneity of primary sarcomas located in the pelvis makes it difficult to find homogeneous cohorts. OBJECTIVE: To describe the life and functional prognosis depending on the histological type of sarcoma in a series of locally advanced high-grade pelvis located sarcomas treated by hemipelvectomy. METHODS: A descriptive epidemiological and functional study was conducted on 15 cases treated between 2006 and 2012. Survival analysis, functional assessment, and a comparative study by histological type were performed, comparing chondrosarcomas to other histological diagnoses. RESULTS: The most frequent histological type was chondrosarcoma (46%), and the most frequent location was P2 (periacetabular) (73%). An internal hemipelvectomy was performed in 66% of cases, with a higher incidence (83%) in chondrosarcomas. Overall two-year survival was 54%, with higher survival in the chondrosarcoma group (67%) than in the other sarcomas (43%). Functional status depended on the type of intervention, with no differences in histological type or the performance of the reconstruction. DISCUSSION AND CONCLUSIONS: Hemipelvectomy is a surgical procedure that is indicated for the treatment of locally advanced high grade pelvis located sarcomas, regardless of histological type. The incidence of limb preservation and overall survival is higher in chondrosarcomas compared to other sarcomas.

Moldes individualizados para alineación de la artroplastía primaria de rodilla / Individualized molds for alignment of primary knee arthroplasty

Introducción: Los sistemas de bloque de corte específicos (BCE) se han presentado como una interesante medida para obtener una correcta alineación en la artroplastía de rodilla, aunque se desconoce cuál de todos los métodos existentes para realizar la planificación es el adecuado. Material y métodos: Se ha diseñado un estudio prospectivo comparando dos sistemas de BCE con planificaciones diferentes (Signature con TAC + teleradiografia; Visionaire con RMN) con el sistema convencional de alineación. Se analizaron parámetros radiográficos, funcionales preoperatorios y postoperatorios, estancia hospitalaria, necesidad de transfusión, tiempo quirúrgico y complicaciones asociadas. Resultados: Un total de 10 pacientes fueron intervenidos por cada grupo. No se observaron diferencias estadísticamente significativas entre los dos sistemas de alineamiento específicos y el sistema convencional (p > 0.05), aunque se objetivó una mayor precisión con estos sistemas, siendo discretamente superior en el sistema Signature. También se observó un menor tiempo quirúrgico en los pacientes intervenidos con los BCE, ligeramente inferior en los intervenidos con el sistema Visionaire (p > 0.05). Conclusiones: Los nuevos sistemas BCE pueden ser útiles para mejorar la alineación en la artroplastía de rodilla así como disminuir el tiempo quirúrgico. A la espera de series mayores que corroboren estos datos, los autores recomiendan estos sistemas en aquellos casos en los que los sistemas convencionales no sean adecuados.

Introduction: Patient-specific cutting blocks (PSCB) have been proposed as an interesting option to achieve appropriate alignment in knee arthroplasty. However, there is no information as to which of the available planning methods is the right one. Material and methods: A prospective study was designed to compare two PSCB systems using different planning methods (Signature with CAT scan + teleradiography; Visionaire with MRI) with the standard alignment method. Radiographic and functional pre- and postoperative parameters were analyzed, together with hospital stay, blood transfusion needs, operative time and associated complications. Results: A total of 10 patients per group were operated on. No statistically significant differences were observed between both of the patient-specific alignment systems and the standard system (p > 0.05). However, greater precision was achieved with the former systems and the Signature system was slightly more accurate. Operative time was shorter in patients in whom PSCBs were used, and it was still slightly shorter in those in whom the Visionaire system was used (p > 0.05). Conclusions: The new PSCB systems may be useful to improve alignment in knee arthroplasty and reduce the operative time. While larger case series confirming these data become available, the authors recommend using these systems in cases in which the standard systems do not work properly.

[Individualized molds for alignment of primary knee arthroplasty]. / Moldes individualizados para alineación de la artroplastía primaria de rodilla.

INTRODUCTION: Patient-specific cutting blocks (PSCB) have been proposed as an interesting option to achieve appropriate alignment in knee arthroplasty. However, there is no information as to which of the available planning methods is the right one. MATERIAL AND METHODS: A prospective study was designed to compare two, PSCB systems using different planning methods (Signature with CAT scan + teleradiography; Visionaire with MRI) with the standard alignment method. Radiographic and functional pre- and postoperative parameters were analyzed, together with hospital stay, blood transfusion needs, operative time and associated complications. RESULTS: A total of 10 patients per group were operated on. No statistically significant differences were observed between both of the patient-specific alignment systems and the standard system (p > 0.05). However, greater precision was achieved with the former systems and the Signature system was slightly more accurate. Operative time was shorter in patients in whom PSCBs were used, and it was still slightly shorter in those in whom the Visionaire system was used (p > 0.05). CONCLUSIONS: The new PSCB systems may be useful to improve alignment in knee arthroplasty and reduce the operative time. While larger case series confirming these data become available, the authors recommend using these systems in cases in which the standard systems do not work properly.

[Total knee arthroplasty in a patient with meniscal transplantation]. / Artroplastía total de rodilla en paciente con trasplante meniscal.

BACKGROUND: The natural history of a knee subjected to total meniscectomy leads to poor outcomes, so we should be careful with these lesions. Meniscal transplantation may be a proper treatment for these patients as it involves a good medium-term survival. MATERIAL AND METHOD: We report the case of a 52 year-old male who underwent meniscal transplantation and developed left gonarthrosis. The surgical approach consisted of medial longitudinal arthrotomy and implantation of a posterior stabilized prosthesis after releasing the soft tissues, which were very retracted. RESULTS: At the one year follow-up the operated knee had an articular range of 0-110 degrees, with no gap and no pain; no external support was required for walking. CONCLUSIONS: Despite the fact that most case series report good short- and medium-term results, some patients do not have good results and need a total knee prosthesis.

[Clinical and functional outcome of unicompartmental knee arthroplasty: influence of the mechanical axis correction]. / Valoración clínico funcional tras artroplastia unicompartimental de rodilla. Influencia de la corrección del eje mecánico.

OBJECTIVES: Clinical and functional outcome of the knee after Unicompartmental Knee Arthroplasty (UKA) and its correlation with lower limb mechanical axis correction. MATERIAL AND METHODS: We have reviewed the outcome of 29 UKA, corresponding to 29 patients, with an average follow-up of 4.5 years (3-6 years). The distribution was, 21 women and 8 men, 11 unicompartmental osteoarthritis, 17 femoral condyle necrosis and 1 tibial plateau necrosis, and 27 medial versus 2 lateral affected compartments. The clinical-functional situation of the knees was assessed through the Knee Society Score (KSS), and the mechanical axis through long standing film. To calculate the statistical non-parametric correlation between the different parameters, Spearman's coefficient was used. RESULTS: In the last review, the increases in the mean clinical KSS and functional KSS were significantly different, with +31.24 (±15.7) and +43.66 (±18.4) points, respectively. The mean change in the femorotibial angle was 2°±4°. We did not find any correlation with statistical significance between the average increases obtained in KS scores and: the alignment of the knee before and after the surgery; the thickness of the inserted polyethylene; the variation of the posterior tibial inclination; Insall-Salvati's index. There was no statistically significant association between the variation in the total KS score and the type of implant or the surgical technique used. CONCLUSION: We did not find any correlation between the clinical results and the radiological measurements in this population.

Concentración de células mononucleares como predictor de la población de células madre mesenquimales en aspirado de médula ósea. Estudio comparativo entre cresta ilíaca, metáfisis distal de fémur y metáfisis proximal de tibia / Mononuclear cell concentration as predictive tool of mesenchimal stem cells on bone marrow aspiration. A comparative study between iliac crest, distal femur metaphysis and proximal tibial metaphysis

Objetivo: Investigar la concentración de células mononucleadas (CMNs) en aspirados de médula ósea de las metáfisis distal de fémur y proximal de tibia comparando con la procedente de cresta ilíaca, para valorar su potencial como fuente alternativa para la obtención de células mesenquimales pluripotenciales (MSC). Material y métodos: En 20 pacientes previamente a su cirugía de sustitución total de rodilla se obtuvieron muestras de aspirado de médula ósea de cresta ilíaca, fémur distal y tibia proximal. Las muestras se procesaron en laboratorio para aislamiento de MSCs, cultivo y expansión. Resultados: Se encontraron diferencias estadísticamente significativas (p<0,01) en cuanto a la concentración y viabilidad de las CMNs, siendo superior en cresta ilíaca. La tasa de éxito de los cultivos fue claramente inferior en tibia (47%) respecto a fémur (71%) y cresta ilíaca (90%). A igual número de células plantadas no se encontraron diferencias en el número final ni en la viabilidad de las MSCs obtenidas. Conclusiones: La punción-aspiración de médula ósea en fémur distal y tibia proximal permite la obtención de CMNs y MSCs en menor concentración que la punción de cresta ilíaca (AU)

Objective: Investigate concentration of mononuclear cells in bone marrow aspirates from metaphyseal bone from distal femur and proximal tibia compared to bone marrow from iliac crest to evaluate their potential role as alternative sources to obtain MSCs. Matherial and methods: In 20 patients who where going to receive total knee artrhroplasty surgery at our institution where included. Samples where obtained prior to surgery from three different locations: Iliac crest, distal femoral methaphysis and proximal tibial methaphysis. Samples where processed to isolate MSCs, and then where cultured for in vitro expansion. Results: Significative differences (p<0,01) where observed in concentration and viability of mononucleated cells (CMNs), being superior in samples from iliac crest. At a same number of cells planted for culture no differences where found in final MSCs total number nor their viability. Success rate of cultures where clearly inferior in samples obtained from tibia (47%) than femur (71%) and iliac crest (90%). Conclusion: Aspiration of distal femur and proximal tibia bone marrow provides a lower concentration of CMNs and MSCs than bone marrow aspiration from iliac crest (AU)

Estudio experimental sobre el patrón de penetración del cemento óseo en la artroplastia de rodilla según la técnica de cementación empleada / An experimental study of bone cement penetration in total knee arthroplasty depending on cementing technique used

Objetivo: Evaluar la distribución y penetración del manto de cemento óseo en la artroplastia de rodilla según la técnica de cementación empleada. Material y método: Se cementaron las piezas en el segundo y quinto minuto según dos técnicas: presurización digital directa sobre el modelo (técnica M) o sobre la prótesis (técnica P). Se analizaron digitalmente las fotografías de los modelos cementados, determinando la longitud del manto de cemento, el porcentaje y la media de penetración. Resultados: La mejor calidad del manto de cemento se obtuvo con la técnica M aplicada en el segundo minuto, que logró una penetración media de 4,44 mm y un porcentaje de penetración del 79,36%; la técnica P en el quinto minuto tuvo el peor resultado (2,12 mm y 45,79%), siendo estas diferencias significativas (p=0,029). Los planos de corte tangencial (anterior y posterior) resultaron ser los peor cementados, con una media de penetración de 2 mm. La técnica M consiguió la mayor longitud de cemento en estos dos planos (35 mm y 17,9 mm), mientras que la técnica P cubrió menos del 50% de la longitud del corte (p=0,01). Conclusión: La cementación con presurización digital sobre la superficie ósea consigue mayor profundidad y porcentaje de penetración que la cementación sobre la prótesis. Los cortes femorales tangenciales (anterior y posterior) se cementan de forma precaria si se aplica sobre el implante (AU)

Objective: To assess the distribution and penetration of the cement mantle in knee arthroplasty depending on technique used. Material and method: Parts were cemented in the second and fifth minute using two techniques: digital pressurization (fingerpacking) directly over the model (technique M) or over the implant (technique P). We analyze digitally the photographs of the cemented models determining length of the cement mantle, percentage penetration and mean penetration. Results: The best quality of cement mantle was obtained with the technique M applied in the second minute, which achieved a mean penetration of 4.44 mm and a percentage penetration of 79.36%; technique P in the fifth minute obtained poorer result (2.12 mm and 45.79%), these differences being significant (p = 0.029). The tangential planes (anterior and posterior) proved to be poorer cemented, with a mean penetration of 2 mm. The technique M obtained the longest cement mantle in these two planes (35 mm and 17.9 mm), while tehnique P covered < 50% of the length of the plane (p = 0.01). Conclusions: Fingerpacking pressurization over the bone surface achieves a greater depth and percentage penetration of the cement mantle than cementing over the prosthetic implant. Tangential femoral cuts (anterior and posterior) are fixed unstably if it is cemented over the implant (AU)

Influencia de cefazolina y vancomicina en la resistencia al desgaste del cemento óseo / Impact of cefazolin and vancomycin on resistance to bone cement wear

Objetivo: Evaluar experimentalmente la influencia de la mezcla de dos antibióticos, vancomicina y cefazolina, sobre la resistencia al desgaste del cemento óseo (PMMA). Material y métodos: Se definieron seis grupos de estudio en función del antibiótico y su dosis, realizando tres muestras por grupo, que fueron sometidas a desgaste de su superficie utilizando un tribómetro, según el estándar ASTM G99-05. Se midieron los coeficientes de rozamiento y se cuantificó el desgaste volumétrico de cada una de ellas. Obtuvimos imágenes de microscopía electrónica de barrido de cada muestra para observar las existencia de modificaciones en la superficie de las muestras. Resultados: Todos los grupos presentaron datos de desgaste por debajo de los máximos admitidos para uso comercial. No se demostraron diferencias significativas en el coeficiente de fricción o en el desgaste volumétrico, salvo el grupo 4 (vancomicina 2,5% + cefazolina 2,5%), que presentó un mayor desgaste frente al grupo 3 (vancomicina 2,5%) (p<0,05). Vimos una tendencia de mayor desgaste y menor homogeneidad en los grupos con cefazolina en su composición. Conclusiones: Los cementos óseos actuales pueden soportar mezclas con altas dosis de antibióticos sin modificar sus propiedades mecánicas. Además de la cantidad de antibiótico, es determinante su elección, puesto que no todos los antibióticos afectan por igual a las propiedades del PMMA (AU)

Objective: To evaluate experimentally the impact of the mixture of two antibiotics, vancomycin, and cefazolin, on resistance to bone cement wear (PMMA). Material and Methods: Six study groups were defined according to antibiotic and dose, performing three samples per group, which were subjected to wearing of the surface using a tribometer according to the ASTM G99-05 standard. The friction coefficients were measured and volumetric wear of each of them was quantified. We obtained electron scanning microscope images of each sample to observe the presence of changes in the surface of the samples. Results: All groups had wear data below the maximum admitted for commercial use. No significant differences were shown in friction coefficient or volumetric wear, except in group 4 (2.5% vancomycin + 2.5% cefazolin), which showed greater wear versus group 3 (2.5% vancomycin) (p<0.05). We saw a tendency towards greater wear and lower homogeneity in groups with cefazolin in its composition. Conclusions: Current bone cements can withstand mixtures with high doses of antibiotics without altering their mechanical properties. In addition to the amount of antibiotic, the choice is decisive, as not all antibiotics equally affect the properties of PMMA (AU)