Demostración original de la interferencia de los efectos modeladores corticales expansivos de un entrenamiento sobre los de otro ulterior: (la modelación 'marca el terreno' para la remodelación) / Original demonstration of the interference of the expansive cortical modeling effects of one training on those of another further training: (modeling "sets limits" for remodeling)

La expansión modeladora de la geometría cortical de un hueso inducida por su entorno mecánico podría ser difícil de modificar por estímulos ulteriores con diferente direccionalidad. Este estudio, que por primera vez combina datos tomográficos del peroné (pQCT) y dinamométricos de la musculatura peronea lateral, intenta demostrar que, en individuos jóvenes no entrenados, el entrenamiento en fútbol produce cambios geométricos peroneos expansivos, similares a los del rugby, que podrían interferir en los efectos de un entrenamiento ulterior direccionalmente diferente (carrera larga). Confirmando la hipótesis, los resultados indican, con evidencias originales, 1) la relevancia creciente del uso del pie (rotación externa y eversión provocadas por los peroneos laterales) para la determinación de la geometría peronea (incremento del desarrollo de los indicadores de masa y de diseño óseos), evidenciada por la secuencia creciente de efectos: carrera < fútbol < rugby; 2) la predominancia de esos efectos sobre el desarrollo centro-proximal del peroné para resistir a la flexión lateral, y en la región distal para resistir el buckling (principal sitio y causa de fractura del hueso) y 3.) la relevancia de la anticipación de esos efectos para interferir en la manifestación de los cambios producidos por un entrenamiento ulterior (carrera), cuando los del primero (fútbol) afectan la modelación cortical de modo expansivo. Esta última deducción demuestra, en forma inédita, que un cambio modelatorio expansivo tempranamente inducido sobre la estructura cortical ósea 'delimitaría el terreno'para la manifestación de cualquier otro efecto ulterior por estímulos de distinta direccionalidad. (AU)

The modeling-dependent, geometrical expansion of cortical bone induced by the mechanical environment could be hard to modify by subsequent stimulations with a different directionality. The current study aimed to demonstrate that in young, untrained individuals, training in soccer or rugby enhances the geometric properties of the fibula cortical shell in such a way that the geometrical changes could interfere on the effects of a second training in which the loads are induced in a different direction, e.g. long-distance running. The original findings reported herein confirm our hypothesis and support 1) The relevance of the use of the foot (external rotation and eversion produced by peroneus muscles) to determine fibula geometry (improved development of indicators of bone mass and design) as evidenced by the increasing nature of the effects induced by running < soccer < rugby trainings; 2) The predominance of those effects on the ability of the fibula to resist lateral bending in the centralproximal region (insertion of peroneus muscles), and to resist buckling in the distal region (the main cause and site of the most frequent bone fractures), and 3) The interaction of the effects of a previous training with those of a subsequent training with a different orientation of the loads when the former induced a modeling-dependent expansion of the cortex. Our results support the proposed hypothesis with original arguments by showing that a first, expansive effect induced on cortical bone modeling would set the stage the manifestation of any subsequent effect derived from mechanical stimuli. (AU)

Radiographic study of the development of the pelvis and hip and the femorotibial joints in domestic cats.

OBJECTIVES: The aims of the present study were to monitor, by radiographic examination, the skeletal development of the pelvis and the femorotibial joints of the domestic cat from the first week of life until the closing of the growth plates. METHODS: Radiographic examinations were collected from 15 domestic cats at weekly intervals during the first month and every 2 weeks from the second to the fourth month of age. After that, examinations were performed monthly until the age of 18 months. RESULTS: The ischiopubic growth plate closed at 2 months of age, followed by the fusion of the iliopubic, ilioischial, proximal femoral, greater trochanter and proximal fibular growth plates. The distal femur and proximal tibial growth plates were the last to close, with fusion occurring at 18 months. The mean time to closure of the iliopubic, ilioischial and distal femoral growth plates was shorter in females. The ossification centers first appeared, in ascending order, beginning with the lesser trochanter, followed by the greater trochanter, proximal fibular epiphysis, tibial tuberosity, patella, ischial tuberosity and lateral sesamoid of the popliteus muscle. CONCLUSIONS AND RELEVANCE: The complete closure of the growth plates of domestic cats occurs at approximately 18 months of age. Skeletal maturation at approximately 18 months of age is an important parameter to be considered in radiographic evaluation of certain skeletal changes, evolution of fractures and nutritional imbalance.

Perone distal estudio anatomico con placa de osteosintesis / Anatomical study of fibula plate location osteosynthesis

La fractura de tobillo es una patologíatraumática muy frecuente, que cuando debe ser intervenidaquirúrgicamente, lo habitual es el uso de placade osteosíntesis, la misma puede ser colocada en unade sus dos caras, externa o posterior. La externa se encuentradividida por una cresta en una superficie triangularanterior subcutánea y una pósteroexterna, diferentesautores recomiendan la colocación en una u otracara. El objetivo de este trabajo es evaluar cuál de lascaras del tercio distal del peroné, es la más adecuadaanatómicamente para la colocación de la placa deosteosíntesis.MATERIALES Y MÉTODOS: Se evaluó el tercio distal de25 perones, 15 correspondieron al lado izquierdo y 10 allado derecho las muestras fueron obtenidas de la Cátedrade Anatomía Normal. Facultad de Ciencias Médicas(UNC. Córdoba), se realizaron mediciones tanto de lacara ánteroexterna como de la pósteroexterna. Para lamedición se utilizó un calibre digital.RESULTADOS: Los resultados obtenidos indicaron unadistancia promedio de la cara ánteroexterna de 75 mmdesde el maléolo hasta el vértice de la cresta (rango 65mm a 92 mm) y una distancia promedio de 65 mm en lacara pósteroexterna desde la fosita de los peroneos hastala unión de ambas (rango 60 mm a 72.3 mm).CONCLUSIÓN: El estudio anatómico del peroné distalnos permite afirmar que ninguna de sus caras terminansiendo ideales para la colocación de una placa, estaosteosíntesis de 7 orificios puede utilizarse en ambascaras ánteroexterna y pósteroexterna, cuando se tratade una fractura transindesmal, pero no es anatómicamenteviable colocar en la cara ánteroexterna cuandohablamos de fracturas suprasindesmales. Debe colocarseen la cara pósteroexterna aunque en esta partetambién interfiera la unión de ambas caras...

The fibula is a long thin bone thatarticulates with the tibia at both ends. A study wasconducted over 25 perones anatomical and analyzed thedistal third. Our goal is to evaluate which of the faces ofthe distal fibula is the most appropriate anatomically tothe placement of the osteosynthesis plate.MATERIALS AND METHODS: Was evaluated peronesdistal third of 25, 15 corresponded to the left and rightside 10 samples were obtained from plants of NormalAnatomy Chair Faculty of Medical Sciences (UNCCordoba), were measured both as the anterolateral theposterolateral was used for measuring a digital caliper.RESULTS: The results showed an average distance of75 mm anterolateral from the malleolus to the apex of theridge (range 65 to 92 mm) and an average distance of 65mm in the posterolateral from the pit of the peroneal tothe junction of two (range 60 to 72.3 mm).CONCLUSION: We conclude that none of its faces endup being suitable for placement of a plate, theosteosynthesis plate of holes 7 may be used on both sidesanterolateral and posterolateral when dealing with fractureanatomically syndesmotic but not feasible to placeon the face when speaking of fractures anterolateralsuprasindesmales. Should be placed in the posterolateralbut also interfere in this part of the union of both sides...