Finite element graft stress for anteromedial portal, transtibial, and hybrid transtibial femoral drillings under anterior translation and medial rotation: an exploratory study.

Stress concentration on the Anterior Cruciate Ligament Reconstruction (ACLr) for femoral drillings is crucial to understanding failures. Therefore, we described the graft stress for transtibial (TT), the anteromedial portal (AM), and hybrid transtibial (HTT) techniques during the anterior tibial translation and medial knee rotation in a finite element model. A healthy participant with a non-medical record of Anterior Cruciate Ligament rupture with regular sports practice underwent finite element analysis. We modeled TT, HTT, AM drillings, and the ACLr as hyperelastic isotropic material. The maximum Von Mises principal stresses and distributions were obtained from anterior tibial translation and medial rotation. During the anterior tibia translation, the HTT, TT, and AM drilling were 31.5 MPa, 34.6 Mpa, and 35.0 MPa, respectively. During the medial knee rotation, the AM, TT, and HTT drilling were 17.3 MPa, 20.3 Mpa, and 21.6 MPa, respectively. The stress was concentrated at the lateral aspect of ACLr,near the femoral tunnel for all techniques independent of the knee movement. Meanwhile, the AM tunnel concentrates the stress at the medial aspect of the ACLr body under medial rotation. The HTT better constrains the anterior tibia translation than AM and TT drillings, while AM does for medial knee rotation.

Unique case study: Impact of single-session neuromuscular biofeedback on motor unit properties following 12 days of Achilles tendon surgical repair.

We explored the first evidence of a single-session neuromuscular biofeedback effect on motor unit properties, neuromuscular activation, and the Achilles tendon (AT) length 12 days after undergoing AT surgical repair. We hypothesized that immediate neuromuscular biofeedback enhances motor unit properties and activation without causing AT lengthening. After 12 days AT surgical repair, Medial Gastrocnemius (MG) motor unit decomposition was performed on a 58-year-old male before and after a neuromuscular biofeedback intervention (surface electromyography (sEMG) and ultrasonography), involving unressited plantar flexion. The analysis included motor unit population properties, sEMG amplitude, force paradigm, and AT length. There were increased MG motor unit recruitment, peak and average firing rate, coefficient of variation, and sEMG amplitude, and decreased recruitment and derecruitment threshold in the repaired AT limb. The non-injured limb increased the motor unit recruitment, and decreased the coefficient of variation, peak and average firing rate, inter-pulse interval, derecruitment threshold and sEMG amplitude. The AT length experienced -0.4 and 0.3 cm changes in the repaired AT and non-injured limb, respectively. This single-session neuromuscular biofeedback 12 days after AT surgery shows evidence of enhanced motor unit properties and activation without signs of AT lengthening when unresisted plantar flexion is performed in the repaired AT limb.

Multiclass Support Vector Machine improves the Pivot-shift grading from Gerdy's acceleration resultant prior to the acute Anterior Cruciate Ligament surgery.

INTRODUCTION: Rotatory laxity acceleration still lacks objective classification due to interval grading superposition, resulting in a biased pivot shift grading prior to the Anterior Cruciate Ligament (ACL) reconstruction. However, data analysis might help improve data grading in the operative room. Therefore, we described the improvement of the pivot-shift categorization in Gerdy's acceleration under anesthesia prior to ACL surgery using a support vector machine (SVM) classification, surgeon, and literature reference. METHODS: Seventy-five patients (aged 30.3 ± 10.2 years, and IKDC 52.0 ± 16.5 points) with acute ACL rupture under anesthesia prior to ACL surgery were analyzed. Patients were graded with pivot-shift sign glide (+), clunk (++), and (+++) gross by senior orthopedic surgeons. At the same time, the tri-axial tibial plateau acceleration was measured. Categorical data were statistically described, and the accelerometry and categorical data were associated (α = 5%). A multiclass SVM kernel with the best accuracy trained by orthopedic surgeons and assisted from literature for missing data was compared with experienced surgeons and literature interval grading. The cubic SVM classifier achieved the best grading. RESULTS: The intra-group proportions were different for each grading in the three compared strategies (p < 0.001). The inter-group proportions were different for all comparisons (p < 0.001). There were significant (p < 0.001) associations (Tau: 0.69, -0.28, and -0.50) between the surgeon and SVM, the surgeon and interval grading, and the interval and SVM, respectively. CONCLUSION: The multiclass SVM classifier improves the acceleration categorization of the (+), (++), and (+++) pivot shift sign prior to the ACL surgery in agreement with surgeon criteria.

Evaluation of atraumatic hip instability measured by triaxial accelerometry during walking.

Hip joint instability has been targeted as an important issue that affects normal hip function. The diagnosis of hip instability could be very challenging and currently, there is no definitive diagnostic test. Hip instability results in an excessive amount of translation of femoroacetabular articulation, leading to changes on the dynamic loading of the hip. These changes in femoroacetabular translation could be evaluated by human movement analysis methods. The purpose of this study was to describe the triaxial and overall magnitude of acceleration in patients diagnosed with hip instability during gait cycle and compare those results with a control group. Our hypothesis was that acceleration values obtained from the instability group would be higher than asymptomatic controls. Ten patients with previously diagnosed hip instability were included and 10 healthy and asymptomatic subjects were enrolled as control group. Triaxial accelerometers attached bilaterally to the skin over the greater trochanter were used to record acceleration during walking on a treadmill. The overall magnitude of acceleration and the axial, anteroposterior and mediolateral accelerations (x/y/z) were obtained during gait. Mean overall magnitude of acceleration was higher in the hip instability group compared with the control group, 1.51 g (SD: 0.23) versus 1.07 g (SD: 0.16) (P = 0.022). The axial, anteroposterior and mediolateral accelerations significantly differed between the two groups. The axial and mediolateral accelerations showed to be higher for the hip instability group while the anteroposterior axis acceleration was lower.

Efectos de múltiples exposiciones a sevoflurano a dosis sub-CAM en la neuroapoptosis y la función cognitiva en el periodo neonatal / Effects of multiple exposures to sevoflurane at sub-MAC doses on neuroapoptosis and cognitive function during the neonatal period

Introducción: Recientes estudios han sugerido que los niños con múltiples exposiciones anestésicas tienen un mayor riesgo de deterioro neurocognitivo. Objetivo: Analizar los efectos neurodegenerativos a nivel histológico, cognitivo y del comportamiento posterior a exposiciones repetidas al sevoflurano a dosis inferiores a la concentración alveolar minina en ratas neonatales. Métodos: Se expusieron ratas Wistar de 5-7 días durante una hora a sevoflurano al 2,3%; una, 2 o 3 veces con intervalos de 24 h entre exposición. Posteriormente se determinó el efecto del anestésico en la neuroapoptosis mediante marcación inmunohistoquímica con caspasa-3, Fox-3 y CD95. El aprendizaje fue evaluado con el laberinto acuático de Morris, y el comportamiento relacionado a ansiedad, con laberinto elevado en cruz. Resultados: En todos los grupos experimentales se evidenció apoptosis neuronal medida por caspasa-3, siendo más marcada en el grupo de sevoflurano y en grupos de primera exposición. En laberinto elevado en cruz se encontró un tiempo total de permanencia en brazos abiertos (t test p = 0,113) estadísticamente no significativo con respecto al grupo control. En el laberinto acuático de Morris se encontró diferencia estadísticamente significativa (t test p < 0,001) cuando se compara el tiempo de realización de la prueba con respecto al grupo control. Conclusiones: La exposición a sevoflurano en ratas neonatales durante periodos cortos y repetidos induce muerte neuronal posiblemente por apoptosis a través de la activación de caspasa-3. Como consecuencia produce déficit de aprendizaje, principalmente en la adquisición de memoria espacial.

Introduction: Recent studies have suggested that children who are exposed multiple times to anesthesia have an increased risk of neurocognitive impairment. Objective: To analyze at a histological level the neurodegenerative, cognitive and behavioral effects following repeated exposures to sevoflurane at doses below the minimum alveolar concentration in neonatal rats. Methods: Wistar rats were exposed to 2.3% sevoflurane, one, two or three times for 1 h, in the course of 5-7 days, with 24-h intervals between each exposure. The neuroapoptotic effect of the anesthetic agent was subsequently determined using immunohistochemical labeling with caspase-3, Fox-3 and CD95. Learning was assessed with the Morris Water Maze, and the anxiety-related behavior was assessed with the Elevated Plus-Maze. Results: Every experimental group showed evidence of neuronal apoptosis measured withcaspase-3; however, the apoptosis was more evident in the sevoflurane group and in the first exposure groups. The total time spent in the open arms of the Elevated Plus-Maze (t test p = 0.113) was not statistically significant as compared to the control group. When comparing the test time vs. the control group, the Morris Water Maze showed a statistically significant difference (t test p < 0.001). Conclusions: Sevoflurane exposure of neonate rats for short and repeated time intervals induces neuronal death probably due to apoptosis, through caspase-3 activation. This results in learning deficit, particularly in terms of spatial memory acquisition.

Artrodesis tibiotalocalcanea con placa philos: experiencia en el Hospital Militar Central. Enero 2007 a diciembre de 2009 / Tibiocalcaneal arthrodesis with philos plate: experience in the Hospital Militar Central - January 2007 to December 2009 / Artrodese tibiotalocalcânea com placa philos: experiência no Hospital Militar Central. Janeiro de 2007 a dezembro de 2009

Estudio descriptivo observacional, retrospectivo tipo serie de casos, realizado entre enero de 2007 y diciembre de 2009 en el Hospital Militar Central. Fueron tratados 21 pacientes con artrosis de la articulación tibio talar y subtalar de etiología diversa, con seguimiento mínimo de 6 meses. Se evaluó; la función pre operatoria y post operatoria por medio de la escala AOFAS, el dolor mediante la escala visual análoga, el tiempo de consolidación con controles radiográficos, el tipo de injerto utilizado y las complicaciones asociadas. Se encontraron como complicaciones 2 pacientes con infección superficial, que requirió manejo con antibiótico endovenoso, y 2 pacientes con retardo en la consolidación que requirieron cirugía de revisión. Los resultados obtenidos demuestran que la artrodesis tibiotalocalcanea con placa philos es un excelente método de fijación (90,4% consolidación) en pacientes con artrosis del tobillo y sub talar y mala calidad ósea...

Descriptive, observational, retrospective, case-series study conducted between January 2007 and December 2009 in the Hospital Militar Central. Twenty one patients with tibiotalar and subtalar joint arthrosis of diverse etiology were treated, with follow-up of at least 6 months. The following facts were assessed: pre-operatory and post-operatory function through the AOFAS scale, pain according to the visual analogue scale, time to consolidation by radiographic controls, type of used graft and associated complications. Complications were found in 2 patients with superficial infection which required management with intravenous antibiotic, and 2 patients showing consolidation delay who required revision surgery. The obtained results demonstrate that tibiotalocalcaneal arthrodesis with Philos plate is an excellent fixation method (90.4% consolidation) in patients with ankle and subtalar arthrosis and poor bone quality...

Estudo descritivo observacional, retrospectivo tipo série de casos, realizado entre janeiro de 2007 e dezembro de 2009 no Hospital Militar Central. Foram tratados 21 pacientes com artrose na articulação tíbio talar e subtalar de etiologia diversa, com acompanhamento mínimo de 6 meses. Foi avaliada a função pré-operatória e pós-operatória por meio da escala AOFAS, a dor mediante a escala visual análoga, o tempo de consolidação com controles radiográficos, o tipo de enxerto utilizado e as complicações associadas. Foram encontradas como complicações 2 pacientes com infecção superficial, que requereram tratamento com antibiótico endovenoso, e 2 pacientes com retardo na consolidação que requereram cirurgia de revisão. Os resultados obtidos demonstram que a artrodese tibiotalocalcânea com placa philos é um excelente método de fixação (90,4% consolidação) em pacientes com artrose do tornozelo e sub-talar e má qualidade óssea...

Células de glía envolvente olfatoria: potencial para la reparación de lesiones del sistema nervioso central / Olfactory ensheathing glia cells: potential element to repair the injury of the central nervous system

Las células de la glía envolvente olfatoria hacen parte del tejido del sistema olfatorio. Este sistema puede presentar neurogénesis durante de toda la vida, lo cual permite el crecimiento de axones de neuronas sensoriales desde la periferia y la posterior formación de sinapsis con receptores axonales olfatorios dentro del sistema nervioso central en el bulbo olfatorio. El conocimiento de las propiedades funcionales de dichas células de la glía envolvente en el sistema olfatorio ha promovido su estudio como posibles elementos para el tratamiento de lesiones del sistema nervioso central, en especial, las lesiones de médula espinal. Se han reportado resultados que muestran que las células de la glía envolvente pueden tener alguna habilidad como promotoras de crecimiento y regeneración axonal y, también, como células remielinizantes.El objetivo de esta revisión es hacer un resumen del conocimiento actual sobre las células de la glía envolvente olfatoria, haciendo énfasis en sus características biológicas y funcionales, y en los resultados de estudios publicados en el campo de la regeneración en lesiones de médula espinal.