Floating Knee Arthrodesis After Prosthetic Knee Infection: A Report of 48 Cases.

BACKGROUND: Knee arthrodesis is a means of avoiding above-knee amputation after a prosthetic joint infection (PJI). The objective of this study was to analyze the results of floating knee arthrodesis in patients who had a history of aprosthetic knee infection. The analysis consisted of determining reinfection rates, functional results, and the survival of arthrodesis. METHODS: There were 48 patients who underwent a cemented floating knee arthrodesis in cases of PJI retrospectively included in the study, having been operated on between 2012 and 2020. In addition to being evaluated clinically, analytically, and radiographically, the patients were assessed functionally by means of a newly-created scale. RESULTS: At a mean follow-up of 4 years (1 year to 9 years), 7 patients suffered reinfection (14.6%). The recurrence of infection was not observed to be significantly affected by sex (P = .16), age(P = .09), or the type of surgery previously undergone (P = .18), nor was the McPherson Host Grade (P = .4) observed to have a significant effect. Patients who had a McPherson Limb Grade 3 were more likely to suffer reinfection than those with a McPherson Limb Grade 2 (P = .034). There were 26 patients (54%)fully evaluated and scored on the Knee Arthrodesis Functional Scale(BAOR). For 11 patients (42%), the results were evaluated as excellent, for 11 (42%) acceptable, for 3 (12%) low, and for 1(4%) poor. CONCLUSION: The arthrodesis nail is an effective and safe procedure for patients who have a recurrent PJI, providing an effective alternative when the criteria for a new revision total knee arthroplasty are not met.

Complete tumor necrosis after neoadjuvant chemotherapy defines good responders in patients with Ewing sarcoma.

BACKGROUND: Survival in patients who have Ewing sarcoma is correlated with postchemotherapy response (tumor necrosis). This treatment response has been categorized as the response rate, similar to what has been used in osteosarcoma. There is controversy regarding whether this is appropriate or whether it should be a dichotomy of complete versus incomplete response, given how important a complete response is for in overall survival of patients with Ewing sarcoma. The purpose of this study was to evaluate the impact that the amount of chemotherapy-induced necrosis has on (1) overall survival, (2) local recurrence-free survival, (3) metastasis-free survival, and (4) event-free survival in patients with Ewing sarcoma. METHODS: In total, 427 patients who had Ewing sarcoma or tumors in the Ewing sarcoma family and received treatment with preoperative chemotherapy and surgery at 10 international institutions were included. Multivariate Cox proportional-hazards analyses were used to assess the associations between tumor necrosis and all four outcomes while controlling for clinical factors identified in bivariate analysis, including age, tumor volume, location, surgical margins, metastatic disease at presentation, and preoperative radiotherapy. RESULTS: Patients who had a complete (100%) tumor response to chemotherapy had increased overall survival (hazard ratio [HR], 0.26; 95% CI, 0.14-0.48; p < .01), recurrence-free survival (HR, 0.40; 95% CI, 0.20-0.82; p = .01), metastasis-free survival (HR, 0.27; 95% CI, 0.15-0.46; p ≤ .01), and event-free survival (HR, 0.26; 95% CI, 0.16-0.41; p ≤ .01) compared with patients who had a partial (0%-99%) response. CONCLUSIONS: Complete tumor necrosis should be the index parameter to grade response to treatment as satisfactory in patients with Ewing sarcoma. Any viable tumor in these patients after neoadjuvant treatment should be of oncologic concern. These findings can affect the design of new clinical trials and the risk-stratified application of conventional or novel treatments.

Perfil de fracturas por fragilidad en un hospital universitario / Profile of fragility fractures in a university hospital

Introducción: Cerca de 200 millones de personas en el mundo sufren de osteoporosis. En promedio ocurre una fractura cada 3 segundos y su prevalencia ha ido en aumento de manera exponencial en la última década. A pesar de ser un problema de salud pública en Colombia carecemos de estadísticas que muestren la magnitud de la enfermedad. Materiales y métodos: Estudio descriptivo transversal con componente analítico de pacientes con fracturas por fragilidad atendidos por el servicio de Urgencias. Se calculó su incidencia, caracterización de la población y asociaciones con significancia estadística entre las variables de interés. Resultados: Se encontró una incidencia de 10.7 FF /100 fracturas/año y 1.02 FF/100 pacientes atendidos en el hospital/año. Mayor incidencia a los 57 años, 80% en mujeres, principalmente cesantes. La fractura de radio distal tuvo mayor prevalencia seguida de cadera y húmero proximal. El 85% de los pacientes no tenía antecedente de osteoporosis. Se encontraron asociaciones estadísticamente significativas entre edad y localización, sexo y edad, sexo y localización como principales. Discusión: Con el envejecimiento poblacional, la incidencia de FF ha ido en aumento, encontramos resultados demográficos similares a los reportados en la literatura, una mayor frecuencia en mujeres y comprometiendo principalmente el radio distal. Debido a las limitaciones metodológicas del estudio éste nos sirve como generador de hipótesis basados en las asociaciones encontradas. Consideramos importante la identificación, diagnóstico e inicio de tratamiento en estos pacientes pues se disminuye el riesgo de nueva caída, morbilidad y mortalidad asociadas. Nivel Evidencia III: Estudio Descriptivo - Analítico.

Introduction: Nearly 200 million people in the world suffer from osteoporosis. On average, a fracture occurs every 3 seconds and its prevalence has been increasing exponentially in the last decade. Despite being a public health problem in Colombia, we lack statistics that show the magnitude of the disease. Materials and methods: Cross-sectional descriptive study with an analytical component of patients with fragility fractures treated by the Emergency Department. Its incidence, characterization of the population and associations with statistical significance between the variables of interest were calculated. Results: An incidence of 10.7 FF/100 fractures/year and 1.02 FF/100 patients treated in the hospital/year was found. Higher incidence at 57 years of age, 80% in women, mainly unemployed. Distal radius fracture had the highest prevalence followed by hip and proximal humerus. 85% of patients had no history of osteoporosis. Statistically significant associations were found between age and location, sex and age, sex and location as the main ones. Discussion: With population aging, the incidence of FF has been increasing, we found demographic results similar to those reported in the literature, a higher frequency in women and mainly involving the distal radius. Due to the methodological limitations of the study, it serves as a generator of hypotheses based on the associations found. We consider the identification, diagnosis and initiation of treatment in these patients to be important as it reduces the risk of new falls, associated morbidity and mortality. Level III Evidence: Descriptive - Analytical Study.

Clear cell chondrosarcoma of the proximal tibia - case report

ABSTRACT Introduction: Clear cell chondrosarcomas are a rare type of low-grade chondrosarcoma. Unlike conventional chondrosarcomas, these tumors occur mainly in the epiphyses of long bones, especially in the proximal femur and proximal humerus. Given their lytic characteristics with a cystic appearance, they can be mistaken for bone cysts and diagnosed late. Diagnosis must be made based on histopa-thology and immunohistochemistry. Likewise, negativity for cytokeratins and anti-endomysial antibodies are tools to rule out the differential diagnosis of metastasis. The treatment of this low-grade chondral lesion is surgical, either with intralesional management or complete resection. Case presentation: This is the case of a 46-year-old woman who consulted the orthopedic oncology service of a quaternary care institution due to medial knee pain at the level of the proximal tibia for 8 months. Diagnostic imaging studies showed a cystic lesion in the lateral tibial plateau; a biopsy of the lesion was performed, and clear cell chondrosarcoma was diagnosed based on histopathology and immunohistochemistry. Surgical management included tumor-free resection margins and reconstruction of the bone defect with a structural allograft of the proximal tibia. The patient progressed satisfactorily. Conclusions: This was the case of a patient with a subtype of low-grade chondrosarcoma that is rare in incidence and location, who was diagnosed based on immunohistochemistry and treated surgically to achieve a successful limb salvage.

RESUMEN Introducción. El condrosarcoma de células claras es un subtipo de tumor poco frecuente del grupo de los condrosarcomas de bajo grado. A diferencia de los condrosarcomas convencionales, estos tumores se presentan principalmente en epífisis de huesos largos. Dadas sus características líticas de aspecto quístico, pueden confundirse con quistes óseos, por lo que su diagnóstico debe hacerse por histopatología e inmunohistoquímica mediante biopsia. Igualmente, la negatividad para citoqueratinas y anticuerpos antiendomisio es una herramienta para descartar el diagnóstico diferencial de metástasis. Su tratamiento es quirúrgico, bien sea con manejo intralesional o resección completa con márgenes libres. Presentación del caso. Mujer de 46 años quien consultó al servicio de ortopedia oncológica de una institución de IV nivel de atención por un cuadro clínico de 8 meses de evolución consistente en dolor en la cara medial de la rodilla izquierda a nivel de la tibia proximaluna. Se practicaron imágenes diagnósticas que mostraron una lesión quística en el platillo tibial lateral; se ordenó biopsia de la lesión, y mediante histopatología e inmunohistoquímica se diagnosticó condrosarcoma de células claras. Se realizó un manejo quirúrgico con resección de la lesión con márgenes libres y una reconstrucción del defecto óseo con un aloinjerto estructural de tibia proximal, con lo cual se obtuvo una evolución satisfactoria. Conclusiones. Se presenta el caso de una paciente con un subtipo de condrosarcoma de bajo grado infrecuente en su presentación y localización, quien fue diagnosticada mediante inmunohistoquímica y tratada quirúrgicamente para lograr un salvamento exitoso de su extremidad.

Amphiphilic Thiol Polymer Nanogel Removes Environmentally Relevant Mercury Species from Both Produced Water and Hydrocarbons.

Technologies for removal of mercury from produced water and hydrocarbon phases are desired by oil and gas production facilities, oil refineries, and petrochemical plants. Herein, we synthesize and demonstrate the efficacy of an amphiphilic, thiol-abundant (11.8 wt % S, as thiol) polymer nanogel that can remove environmentally relevant mercury species from both produced water and the liquid hydrocarbon. The nanogel disperses in both aqueous and hydrocarbon phases. It has a high sorption affinity for dissolved Hg(II) complexes and Hg-dissolved organic matter complexes found in produced water and elemental (Hg0) and soluble Hg-alkyl thiol species found in hydrocarbons. X-ray absorption spectroscopy analysis indicates that the sorbed mercury is transformed to a surface-bound Hg(SR)2 species in both water and hydrocarbon regardless of its initial speciation. The nanogel had high affinity to native mercury species present in real produced water (>99.5% removal) and in natural gas condensate (>85% removal) samples, removing majority of the mercury species using only a 50 mg L-1 applied dose. This thiolated amphiphilic polymeric nanogel has significant potential to remove environmentally relevant mercury species from both water and hydrocarbon at low applied doses, outperforming reported sorbents like sulfur-impregnated activated carbons because of the mass of accessible thiol groups in the nanogel.

Catalytic use of TiO2 nanowires in the photodegradation of Benzophenone-4 as an active ingredient in sunscreens.

Water contamination has compromised the quality of this resource during the last years with the presence of persistent organic pollutants. Because of the resistance of these compounds to degradation, several advance oxidation techniques have been proposed. In this study, we report the employment of an advance oxidation technique in the degradation of benzophenone-4 (BP-4), using TiO2 as catalyst, which was obtained following a fast-hydrothermal method. TiO2 nanowires (TiO2NWs) were fully characterized considering the morphology, elemental composition, oxidation states, vibrational modes and crystalline structure with SEM and TEM, EDS, XPS, FTIR and XRD, respectively. The photocatalytic degradation was carried out using a home-made photoreactor under slightly acidic conditions achieving an average of 90% removal. It was determined that the photocatalysis is the most probable route of degradation since the photolysis or catalysis procedures produce negligible contributions. An apparent kinetic constant of 1.29 × 10-2 min-1 was determined, according to a pseudo-first order reaction.

Impact of mercury speciation on its removal from water by activated carbon and organoclay.

Mercury (Hg) speciation can affect its removal efficiency by adsorbents. This study assessed the removal of dissolved inorganic Hg(II) species (Hg(II)*), ß-HgS nanoparticles (HgS NP), and Hg complexed with dissolved organic matter (Hg-DOM) by three sorbents: activated carbon (AC), sulfur-impregnated activated carbon (SAC), and organoclay (OC). The effect of ionic composition, solution ionic strength, and natural organic matter (NOM) concentration on the removal of each Hg species was also evaluated. The three adsorbents were all effective in removing Hg(II)*, Hg-DOM, and HgS NPs. Increasing ionic strength decreased the removal of Hg(II)* species due to the formation of ionic Hg species with lower affinity for the sorbents. Added NOM decreased the removal of Hg(II)* and HgS NPs by all sorbents with the OC sorbent being most susceptible to NOM fouling. On a surface area-normalized basis, the OC removed all types of Hg species better than the AC and SAC samples. Moreover, adsorbed Hg-DOM transformed to a ß-HgS phase on the OC, but not for AC and SAC. These studies indicate that both Hg speciation and the water quality parameters need to be considered when designing sorbent-based emission controls to meet Hg removal targets.

Elemental Analysis of Asphaltenes Using Simultaneous Laser-Induced Breakdown Spectroscopy (LIBS)-Laser Ablation Inductively Coupled Plasma Optical Emission Spectrometry (LA-ICP-OES).

Laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma optical emission spectrometry (LA-ICP-OES) were used simultaneously for the elemental analysis of asphaltene samples using minimum sample pretreatment in combination with low laser energy to reduce the amount of removed particles and avoid carbon deposits in the ablation cell. Quantitative analyses of S, Ni, and V were accomplished with LA-ICP-OES using external calibration with the C line as internal standard. The aromatic/paraffinic nature of the asphaltenes was also obtained throughout the H/C ratio using LIBS and partial least square regression model. The results showed very good agreement (±10%) between the concentration obtained by LA-ICP-OES and microwave-assisted acid digestion values.

TiO2-Based Nanomaterials for the Production of Hydrogen and the Development of Lithium-Ion Batteries.

The photocatalytic activity of different titanium oxide nanowires containing gold (Au@TiO2NWs), and gold-graphene (Au@TiO2NWs-graphene), was evaluated by studying the reaction of hydrogen production by water splitting under UV-vis light. The composites showed high surface areas, with values above 300 m2 per gram, even after the incorporation of gold and graphene on the surface of titanium oxide nanowires. The highest hydrogen production of Au@TiO2NWs was 1436 µmol h-1 g-1, under irradiation at 400 nm, and with a gold loading of 10 wt %. This photocatalytic activity was 11.5 times greater than that shown by the unmodified TiO2NWs. For the Au@TiO2NWs-graphene composites, the highest hydrogen amount obtained was 1689 µmol h-1 g-1, at loadings of 10 and 1 wt % of gold and graphene, respectively. The photocatalytic activity of the gold-graphene compounds was 1.2 times greater than that shown by the titanium oxide catalysts and 13.5 times higher than the bare TiO2NWs. Even at wavelengths greater than 500 nm, the compounds exhibited yields of hydrogen above 1000 µmol h-1 g-1, demonstrating the high catalytic activity of the compounds. In addition, TiO2-based materials are of great interest for energy storage and conversion devices, in particular for rechargeable lithium ion batteries. TiO2 has a significant advantage due to its low volume change (<4%) during the Li ion insertion/desertion process, short paths for fast lithium ion diffusion, and large exposed surface, offering more lithium insertion channels. However, the relatively low theoretical capacity and electrical conductivity of TiO2 greatly hamper its practical application. In this work, free-standing electrodes composed by TiO2NWs and carbon nanotubes, CNT@TiO2NWs, were used as anode materials for Li-ion batteries. As a result, the electronic conductivity and mechanical properties of the composite were greatly improved and a good cycling performance was obtained in these batteries. This research shows the potential of TiO2-based materials for the development of new catalysts for hydrogen production and energy storage systems.

Prescribed and Measured Dose Differences for an AP-PA TBI Protocol with Compensation Filter and Ergonomic Patient Support.

INTRODUCTION: A treatment scheme is presented for clinical applications of total body radiation using 6 MV photons. METHODS: The two-field technique, anteroposterior (AP) and posteroanterior (PA), was applied. In vivo dose verification with TLD-100 dosimeters was developed during the first treatment sessions. Dosimetry was performed in several anatomical regions such as head, shoulder, thorax, abdomen, hip, thigh, knee, and ankle in 13 patients as preconditioning for bone marrow transplantation. A prescribed dose of 100 cGy was considered at the level of the patient's coronal plane. Values with least differences between measured and prescribed dose were obtained for the shoulder. RESULTS: Standard deviation percentages of 0.3% and 2.6% were recorded between these doses for AP and PA, respectively. There were larger differences for other contours. In general, a measured dose less than the prescribed dose was observed in all the contours. CONCLUSION: Differences between prescribed and measured doses showed in this study can contribute to a required understanding about the accurate doses in AP-PA total body irradiation (TBI) treatments.

Comparison of mobile- and fixed-bearing cemented total knee arthroplasty.

Concern about polyethylene wear and related osteolysis after knee arthroplasty has developed in the last years. Mobile-bearing knee prostheses were designed in order to reduce the influence of this critical factor on long-term success of total knee replacement. We present a prospective study comparing clinical and radiological results with a mobile-bearing (Ceragyr) and a fixed-bearing knee prosthesis (posterior stabilized Hermes). Clinical results did not show any significant differences in Knee Society scores. We found better results in the mobile-bearing group for pain scores and subjective preference, but the difference did not reach statistical significance. Within the time limits of this study, radiological analysis showed no osteolysis in either group, but longer follow-up will be needed to confirm this.

Synthesis and characterization of large specific surface area nanostructured amorphous silica materials.

Large specific surface area materials attract wide attention because of their applications in adsorption, catalysis, and nanotechnology. In the present study, we describe the synthesis and characterization of nanostructured amorphous silica materials. These materials were obtained by means of a modification of the Stobe-Fink-Bohn (SFB) method. The morphology and essential features of the synthesized materials have been studied using an automated surface area and pore size analyzer and scanning electron microscopy. The existence of a micro/mesoporous structure in the obtained materials has been established. It was also found that the obtained particle packing materials show large specific surface area up to 1,600 m2/g. (To our best knowledge, there is no any reported amorphous silica material with such a higher specific surface area.) The obtained materials could be useful in the manufacture of adsorbents, catalyst supports, and other nanotechnological applications.

Influence of the dielectric medium on the carbonyl infrared absorption peak of acetylferrocene.

The solvent effect on the position of the carbonyl vibrational stretching of acetylferrocene in aprotic media was studied in this work. The solvent-induced shifts in this organometallic compound were interpreted in terms of the alternative reaction field model(SCRF-MO) proposed by Kolling. In contrast to the established trends for carbonyl groups in organic systems, the results suggest that the continuum models for the reaction field are not adequate and that the influence of dipolarity-polarizability described by an inhomogeneous coupling function theta(epsilon )L(n(2)) that assumes optical dielectric saturation is responsible for the carbonyl band shift and, there is empirical evidence that the effect of field-induced intermolecular interaction on band shift, interpreted in terms of the van der Waals forces from the solvent, have a important contribution to this phenomena.

Enfermedades infecciosas y lupus eritomatoso sistémico / Infections ilnees and systemic lupus erythematosus

En la era preesteroidea, las infecciones estaban entre las dos primeras causas de mortalidad entre pacientes con lupus eritomatoso sistémico (LES). Actualmente, esta tendencia se mantiene, ya que el paciente con lupus está inmunocomprometido, no solamente por el tratamiento con inmunosupresores, sino que el LES,por sí mismo, implica deficiencias inmunitarias por producción de varios tipos de anticuerpos dirigidos contra diferentes receptores de las células que median la inmunidad. en este trabajo, se presenta una revisión de literatura médica desde final de 1960 hasta 1999, en torno a la inmunopatogenia de diferentes procesos infecciosos que se presentan en estos pacientes

Piomiositis de los obturadores de la cadera

La miositis infecciosa es una patología de diagnóstico poco frecuente y la similitud existente en su forma de presentación con otras entidades puede conducir a retardo en la instauración de una terapéutica adecuada. Este es un reporte que ejemplifica este hecho. Se presenta el caso de una niña de 6 años con unapiomiositis adecuada espontánea, producida por estafilococo dorado. El cuadro clínico y los exámenes paraclínicos realizados fueron contradictorios y la confirmación del diagnóstico fue posible sólo mediante estudio con resonancia magnética

Enfermedad drepanocítica e infecciones / Sickle cell disease and infection

La enfermedad drepanocítica es la hemoglobinopatía más frecuente en nuestro medio, observándose pricipalmente en personas de raza negra oriundas del continente africano. Serios trastornos inmunológicos como asplenia funcional, funcionamiento anormal de neutrófilos y macrófagos, déficit de opsoninas, falla en la quimiotaxis y del complemento, etc. hacen más susceptibles a estos pacientes a múltiples patologías infecciosas, todo esto aunado con los problemas de oclusión vescular que conducen a isquemia y necrosis. El presente trabajo revisa las patologías infecciosas más frecuentes que afectan a estos pacientes

Diabetes e infección / Diabetes and infection

Durante las década de los años sesenta, setenta y principios de los ochenta, había cierta controversia acerca de si el paciente diabético en realidad se podía catalogar como inmunocomprometido. Los estudios comparativos de entonces confrontaban distintos aspectos de un proceso infeccioso entre los diabéticos y los controles. Actualmente se da como un hecho respaldado por diversos trabajos, cómo la hiperglicemia trastorna los diferentes pasos bioquímicos que se suceden en el polimorfonuclear durante la actividad defensiva. Esto, más los trastornos neuropáticos e isquémicos conforman una tríada para el establecimiento de diferentes estados de infección. La presente revisión tiene por objeto actualizar algunos conceptos sobre y los diferentes procesos infecciosos que se suceden en el paciente diabético irregularmente controlado

Diabetes e infección / Diabetes and infection

Durante las décadas de los años sesenta, setenta y principio de los ochenta, había cierta controversia acerca de si el paciente diabético en realidad se podía catalogar como inmunocomprometido. Los estudios comparativos de entonces confrontaban distintos aspectos de un proceso infeccioso entre los diabéticos y los controles. Actualmente se da como un hecho respaldado por diversos trabajos, cómo la hiperglicemia trastorna los diferentes pasos bioquímicos que se suceden en el PMN durante la actividad defensiva. Esto, más los trastornos neuropáticos e isquémicos conforman una tríada para el establecimiento de diferentes estados de infección. La presente revisión tiene por objeto actualizar algunos conceptos sobre el leucocito diabético y los diferentes procesos infecciosos que se suceden en el paciente diabético irregularmente controlado