[Complex extraction of Küntscher nails. Trephines and other surgical strategies]. / Extracción compleja de clavos de fémur tipo Küntscher. Trefinas y otras técnicas.

INTRODUCTION: Removing an intact or broken intramedullary nail can be a real surgical challenge. In clinical cases many methods have been described, and there are many tools to allow their extraction. In this article, the experience in one of them is presented: the use of trephines. CLINICAL CASES: Three cases of Küntscher intramedullary nails are described, in which it was used, also listing in detail the steps to be followed in a nail extraction, arranging the techniques and assorted tools required to take the nail out, enable the surgeon to make a better extraction plan and prepare in advance any of the necessary resources in the case of failure during the surgery. CONCLUSION: The use of trephines as an extraction system is an infrequent technique. It can be an alternative when the usual methods fail. It does not require new approaches, does not require the integrity of the proximal end of the nail, and can be used in most designs.

INTRODUCCIÓN: La extracción de un clavo intramedular íntegro o roto puede ser un verdadero desafío quirúrgico. Mediante casos clínicos se han descrito diferentes métodos y existen multitud de herramientas que permiten su retirada. En este artículo se presenta la experiencia de una de ellas: el uso de trefinas. CASOS CLÍNICOS: Se describen tres instancias de clavos intramedulares tipo Küntscher detallando los pasos a seguir en una extracción, tras revisar y organizar las técnicas publicadas y las distintas herramientas que se precisan en su realización, de forma que el cirujano pueda planificar mejor la remoción y disponga de los recursos necesarios para poder realizarlas progresivamente si van fracasando durante la cirugía. CONCLUSIÓN: El uso de trefinas como sistema de extirpación es una modalidad poco utilizada, reproducible como alternativa cuando fallan los métodos habituales. No requiere nuevos abordajes y no precisa de la integridad del extremo proximal del elemento, pudiendo ser utilizada en la mayoría de los diseños.

Computer assisted surgery. Its usefulness in different levels of pre-operative deformities.

OBJECTIVE: To compare the results obtained with computer assisted surgery with conventional techniques and evaluate the influence of navigation at different levels of preoperative deformity. MATERIAL AL METHOD: A retrospective study was conducted on 100 cases with primary total knee arthroplasty performed with conventional or computer assisted surgery. A comparison was made of the post-operative mechanical axis of the lower limb between both groups and in terms of pre-operative deformity. RESULTS: Optimal alignment is most often obtained by using the navigation system (62%) than by a conventional technique (36%). Patients with deformities under 10° varus showed a mean post-operative alignment within the optimal range (0±3° deviation from the neutral mechanical axis), while those with more than 15° of varus show an alignment out of range, regardless of the technique used (p=.002). In those with a deformity of between 10 and 15° of pre-operative varus alignment, values were found closer to the neutral axis in the navigation group (178.7°) than in the conventional technique (175.5°), although these differences are not statistically significant (p=.127). CONCLUSION: Post-operative alignment obtained with navigation is better than with the conventional technique, with a smaller percentage of cases out of range, and greater accuracy in placing implants. A potential benefit was observed in navigation for cases with deformities of between 10 and 15° of varus.

Prospects for magnetic nanoparticles in systemic administration: synthesis and quantitative detection.

Methods for the quantitative determination of magnetic nanoparticles in biological matrices, in the frame of biomedical applications, are required to evaluate the particles biodistribution after systemic administration. AC magnetic susceptibility measurements are an alternative method to quantify magnetic nanoparticles in tissues, being able to provide also information on the particle transformations over time and allowing the distinction of the particles from other endogenous species such as the ferritin iron cores. The protocol for particle quantification using AC magnetic susceptibility measurements is described in detail in this article. A summary of synthesis routes towards magnetic nanoparticles is also provided.

Magnetic and structural study of the state of iron in the oral haematinic ferrimannitol ovoalbumin.

From magnetic and structural analyses performed on ferrimannitol ovalbumin, iron in this drug is observed to be present as two-line ferrihydrite nanoparticles, of around 4 nm in diameter, which are superparamagnetic above approximately 20 K. Among other parameters, the temperature dependence of the magnetic out-of-phase susceptibility of this compound has been fully characterised and yields results clearly different from that of ferritin. This characterisation, performed for the first time for an oral haematinic, is of interest in the context of future pharmacological studies of this compound.

Magnetic characterisation of rat muscle tissues after subcutaneous iron dextran injection.

Ex vivo freeze-dried rat muscle tissues, collected at different times t after a single dose of subcutaneously injected iron dextran, have been magnetically characterised. The AC susceptibility of the tissues shows an overall superparamagnetic behaviour and the dependence on t of, especially, the out-of-phase component is remarkably systematic despite the fact that each tissue originates in a different rat individual. The experiments show that the akaganéite (beta-FeOOH) nanoparticles contained in the injected drug are progressively degraded in the living tissue and, at times of the order of 1 month and for all the analysed rat individuals, converge to a magnetically well-defined species with much narrower magnetic activation energy distribution than iron dextran. Thorough transmission electron microscopy experiments of the same tissues indicate the presence of oxyhydroxide particles, whose size decreases for increasing t in agreement with the interpretation of the magnetic susceptibility. The conclusions drawn from the magnetic study do well correspond to the properties of the whole tissue since no biochemical extraction work has been done. The AC susceptibility appears to be a valuable and complementary tool in pharmacological studies of iron-containing drugs.

Artrodesis de rodilla con clavo intramedular / Arthrodesis of the knee with intramedullary nailing

Se revisan 21 artrodesis de rodilla realizadas en 20 pacientes mediante enclavado intramedular, a lo largo de diez años, con un seguimiento medio mayor de 3 años. La causa más frecuente, en 18 casos, fue el fracaso de la artroplastia de rodilla tanto séptico como aséptico. La consolidación primaria de la artrodesis se obtuvo en 16 casos (76 por ciento), en un tiempo medio de 8,1 meses (AU)

Arteriovenous fistula after interlocking nailing of the femur: a case report.

The added technical complexity associated with the transfixion screws for interlocking nailing has introduced new complications. We present a case of a femoral arteriovenous fistula caused by the distal interlocking screw after intramedullary nailing of a comminuted diaphyseal femoral fracture.