Fractura del cuerpo del astrágalo en un niño: a propósito de un caso / Talar body fracture in a 10-year-old boy. Case presentation

La fractura del cuerpo del astrágalo es un cuadro extremadamente raro en la población infantil, y se asocia con mecanismos de alta energía. Se trata de una lesión muy grave y tiene un manejo complejo para el cirujano ortopedista, no exento de complicaciones, como la necrosis avascular, la artrosis postraumática o la seudoartrosis. Presentamos a un niño de 10 años con una fractura-luxación del cuerpo del astrágalo, su manejo de urgencia, el tratamiento definitivo y la evaluación clínico-radiológica al año de la lesión. Nivel de Evidencia: IV

Talar body fractures are an extremely rare presentation in children that are associated with high-energy trauma. They constitute devastating injuries and a management challenge for orthopedic surgeons, which could be further complicated by avascular necrosis, post-traumatic arthritis, and non-union. We report a case of a fracture-dislocation of the talar body in a 10-year-old boy, including emergency management, definitive treatment, and 1-year follow-up clinical and radiologic findings. Level of Evidence: IV

Fracturas periprotésicas de fémur en artroplastia total de rodilla: experiencia con técnica mínimamente invasiva / Peri-prosthetic femoral fractures in total knee arthroplasty: experience using minimally invasive plate osteosynthesis

ANTECEDENTES: La fractura periprótesica de fémur en artroplastia total de rodilla supone uno de los mayores retos quirúrgicos. La tasa de complicaciones generales supera el 30% tanto con tratamiento conservador como con el quirúrgico. Parece que la técnica de osteosíntesis con placas bloqueadas de manera mínimamente invasiva ofrece buenos resultados para el tratamiento de las fracturas en las que no existe movilización del componente femoral. MÉTODOS: Se estudian retrospectivamente, desde enero de 2005 hasta diciembre del 2011, 32 pacientes, evaluando el tiempo de consolidación, el rango de movilidad, la deambulación y el alineamiento final mediante la realización de telemetrías en carga. El seguimiento medio fue de 56,5 meses (25-144). RESULTADOS: Se siguieron 32 pacientes (31 mujeres; un hombre) de los cuales el rango medio de edad fue de 77 años (70-89). Tres pacientes fallecieron (9%) y 4 pacientes (12%) se perdieron en la evolución final. La tasa media de consolidación fue de 16,5 semanas (8-24); no se produjeron infecciones, presentaron 3 seudoartrosis y solo se produjo un alineamiento en excesivo valgo (15°). El balance articular fue similar al previo a la fractura. La deambulación final fue igual a la previa en 24 de los 25 casos. CONCLUSIONES: Es una técnica adecuada para conseguir la consolidación en este tipo de fracturas y restablecer tanto la movilidad previa como un alineamiento correcto de la extremidad.

BACKGROUND: Peri-prosthetic fracture of the distal femur above total knee arthroplasty presents a challenging surgical problem for orthopaedic surgeons, as complication rates for both surgical and non-surgical treatment have been reported to be as high as 30%. The minimally invasive plate osteosynthesis (MIPO) technique seems to have better results than other techniques in this type of fracture when there is no loosening of the femoral implant. METHODS: A total of 32 patients with this fracture were treated from January 2005 to December 2011. A retrospective review was conducted on the weeks of consolidation, range of motion, final alignment, and the ability to walk. The mean follow up was 56.5 months (25-144). RESULTS: A total of 32 (31 female, 1 male) patients, with a mean age 77 (70-89) years old were treated, of whom 3 (9%) died and 4 were lost to follow-up. The mean time of consolidation was 16.5 weeks (8-24). There were no infections, although there were 3 non-unions and 1 malalignment (15° of valgus). We were able to restore the range of motion in every patient as it was before the fracture, as well as the ability to walk outdoors in 24 patients. CONCLUSION: The MIPO technique is a great technique in order to achieve a good range of motion and alignment of these fractures.

Thoracic sagittal plane variations between patients with thoracic adolescent idiopathic scoliosis and healthy adolescents.

PURPOSE: To analyze the sagittal thoracic parameters of different types of progressive thoracic adolescent idiopathic scoliosis (AIS) patients and compare them with healthy adolescents. METHODS: 115 AIS patients with main thoracic curves (Cobb: 59.4 ± 12.7) were prospectively compared with 116 healthy adolescents. The AIS and control (C) groups were homogeneous in terms of age and gender. Standing sagittal radiographs were analyzed for differences in T5-T12 kyphosis, T5-T8 and T9-T12 segmental kyphosis, the change between these two angles, and the double rib contour sign. Statistical analyses were performed using the χ 2, one-way ANOVA, Mann-Whitney U and Student's t tests. RESULTS: The sagittal parameters of Lenke 1 curves did not differ from healthy adolescents (T5-T8: 17.1 ± 10 vs C: 16 ± 7; T9-T12: 6.3 ± 7 vs C: 7.9 ± 5; T5-T12: 23.9 ± 14 vs C: 23.9 ± 8). Compared with the controls, Lenke type 3 curves were globally more hypokyphotic (T5-T12: 18.9 ± 12 vs C: 23.9 ± 8, P = 0.027) due to a "lordosis" of the lower thoracic segment (T9-T12: 0.9 ± 10 vs C: 7.9 ± 5, P = 0.001). Type 2 curves tended to exhibit more pronounced upper thoracic kyphosis (T5-T8: 20.7 ± 12 vs C: 16 ± 7). Both types 2 and 3 require a marked TK changes in the transition between the upper and lower thoracic segments to compensate for global (T5-T12) kyphosis. CONCLUSIONS: In this 2D analysis of moderate AIS, Lenke 1 curves exhibited normal thoracic sagittal parameters, which brings into question the effect of lordosis on the development of single thoracic curves. Lenke 3 curves exhibited lower thoracic segmental hypokyphosis, and the type 2 showed upper segmental hyperkyphosis. These results should be considered when planning a surgical strategy.

Neuron synchronization in the rat gracilis nucleus facilitates sensory transmission in the somatosensory pathway.

We have studied the role of the temporal correlation of multiple cell discharges in the facilitation of the somatosensory information transmission from the gracilis nucleus to the primary somatosensory (SI) cortex in anesthetized rats. Pairs of gracilis neurons or gracilis-SI cortical neurons were recorded during application of 20-ms tactile stimuli in control conditions and after electrical corticofugal stimulation. Cross-correlation of neural spike trains showed significant changes in synchronization of the neuron firing provoked by the corticofugal stimulation. To quantify the time-frequency alterations in the functional association within neuron pairs we used the wavelet coherence measure. We show that electrical stimulation of the SI cortex induces a short-lasting facilitation of tactile responses of projecting gracilis neurons if their receptive fields (RFs) overlap with the RF of the stimulated cortical area (matching condition). Moreover, synchronization of discharges of gracilis neurons with a common RF is increased by activation of the corticofugal projection. Synchronization is favored by a stimulus induced synchronous oscillatory activity of projecting neurons in the range 3-10 Hz. In the matching condition synchronous discharges in the gracilis increment the number of spikes elicited in the SI cortex. Thus the efficacy of the sensory transmission from the gracilis nucleus to the SI cortex is modulated by the corticofugal projection through two complementary mechanisms: (i) by changing the responsiveness (number of elicited spikes) of individual gracilis neurons; and (ii) by a dynamic consolidation of gracilis neurons with a common RF into microcircuits generating synchronous spikes.