Transplantation of a Scaffold-Free Cartilage Tissue Analogue for the Treatment of Physeal Cartilage Injury of the Proximal Tibia in Rabbits

PURPOSE: The purpose of this study was to investigate the effects of transplantation of an in vitro-generated, scaffold-free, tissue-engineered cartilage tissue analogue (CTA) using a suspension chondrocyte culture in a rabbit growth-arrest model. MATERIALS AND METHODS: We harvested cartilage cells from the articular cartilage of the joints of white rabbits and made a CTA using a suspension culture of 2x107 cells/mL. An animal growth plate defect model was made on the medial side of the proximal tibial growth plate of both tibias of 6-week-old New Zealand white rabbits (n=10). The allogenic CTA was then transplanted onto the right proximal tibial defect. As a control, no implantation was performed on the left-side defect. Plain radiographs and the medial proximal tibial angle were obtained at 1-week intervals for evaluation of bone bridge formation and the degree of angular deformity until postoperative week 6. We performed a histological evaluation using hematoxylin-eosin and Alcian blue staining at postoperative weeks 4 and 6. RESULTS: Radiologic study revealed a median medial proximal tibial angle of 59.0degrees in the control group and 80.0degrees in the CTA group at 6 weeks. In the control group, statistically significant angular deformities were seen 3 weeks after transplantation (p<0.05). On histological examination, the transplanted CTA was maintained in the CTA group at 4 and 6 weeks postoperative. Bone bridge formation was observed in the control group. CONCLUSION: In this study, CTA transplantation minimized deformity in the rabbit growth plate injury model, probably via the attenuation of bone bridge formation.

Ankle injuries in the growing skeleton. a review of the recent literature

Ankle injuries arise with significant frequency in the pediatric population, although diagnosis is rarely straightforward. Contact sports, such as football are widely practiced in Saudi athletes, little is carried out to educate them of measures regarding playing conditions and prophylactic steps like foot wear, warming up, and similarly. The usual potential complications associated with trauma to mature skeleton, as well as immature selection includes post-traumatic arthritis, stiffness, reflex sympathetic dystrophy, as well as those seen with physeal damage including leg length discrepancy, angular deformities, or a combination. Knowledge of these injuries, as well as the differences between children and adult skeleton is essential for proper and effective management of these common injuries. This article is a review of anatomy, physiology of physis, diagnostic modalities, prognosis, treatment methods and analyzing, and highlighting data from the published literature regarding ankle injuries in growing skeleton, which is crucial to manage these injuries

Efeito de ondas de choque na placa de crescimento de coelhos / Effect of shock waves upon the growth plate in rabbits

OBJETIVO: Avaliar os efeitos da aplicação de ondas de choque na placa de crescimento de coelhos, variando a energia e o número de ondas aplicadas. MATERIAL E MÉTODOS: Foram estudados 30 coelhos com idade de cinco semanas divididos em seis grupos. O aparelho gerador de ondas de choque foi o OSSATRON (HMT). Os animais foram submetidos a aplicações na placa de crescimento proximal da tíbia esquerda, variando a intensidade (14, 21,28kV) e o número de ondas (1000 e 4000). A tíbia direita foi usada como controle. Os animais foram sacrificados após seis semanas e sua avaliação foi feita por meio da mensuração do comprimento das tíbias e pela análise microscópica da placa de crescimento. Os resultados de mensuração da área da placa e do comprimento das tíbias foram comparados com o grupo controle e entre os grupos, utilizando-se estudos estatísticos. RESULTADOS: Neste estudo não ocorreram alterações estatisticamente significantes nas medidas da área da placa ou do comprimento da tíbia após a aplicação de ondas de choque em nenhum dos grupos. Foi observada tendência de ocorrer uma diferença de crescimento das tíbias entre os grupos submetidos a 1.000 impulsos e os grupos submetidos a 4.000 impulsos, mas esta diferença não foi considerada significante. Foi observada também a formação de hematoma no local da aplicação nos grupos que receberam ondas com maior energia, evoluindo com regressão espontânea sem necessidade de cuidados especiais. CONCLUSÕES: A aplicação de ondas de choque na região proximal da tíbia de coelhos imaturos, nas formas descritas, não teve nenhum efeito na placa de crescimento, de acordo com os métodos de avaliação usados neste estudo.

Gadolinium-enhanced MR imaging of epiphyseal and metaphyseal marrow in normal piglets / 华中科技大学学报（医学）（英德文版）

The purpose of this study is to define the appearance of normal epiphyseal and metaphyseal marrow and normal changes of marrow due to fatty conversion on Gadolinium (Gd)-enhanced MR Imaging. Unenhanced and enhanced T1-weighted MR imaging were performed in proximal and distal femoral ends of 8 healthy piglets at the ages of 2, 4, 6 and 8 weeks, respectively. The changes with age in signal intensity and enhancement ratio of the epiphyseal and metaphyseal marrow with age were examined. The correlation of MRI characteristics with histological findings was studied. Our study showed that marrow of the metaphysis and of periphery of the 2nd ossification center were well vascularized hematopoietic marrow and had great enhancements. The enhancement ratio of metaphysis was greater than that of epiphyseal marrow and both enhancement ratios degraded gradually with age. The central regions of the epiphyseal ossification center and of the diaphysis were of fatty marrow and had little enhancement. It is concluded that on Gd-enhanced MR imaging the hematopoietic marrow of metaphysis and of periphery of the 2nd ossification center had greater enhancement than that of fatty marrow of central region of the 2nd ossification center. All of their enhancements decreased gradually with age.

Osteogénesis comparativa de los cartílagos secundarios de la clavícula y placas epifisiarias de los huesos largos / Comparative osteogenesis of the clavicle secondary cartilages and epiphyseal cartilages of long bones

La clavícula es un hueso formado por osificación membranosa, es decir no se preforma de cartílago. Sin embargo desarrolla cartílagos secundarios como centros de crecimiento, los cuales presentan diferencias morfológicas y funcionales con los cartílagos de crecimiento de los huesos largos. Estos últimos son cartílagos primarios derivados del modelo cartilaginoso original. Se realizó un estudio histológico e inmunohistoquímico de los cartílagos secundarios de la clavícula y de los cartílagos de crecimiento del fémur y húmero, en fetos humanos, entre las 12 y 40 semanas de gestación y en ratones entre 15 días de gestación y 20 días de edad. Se utilizaron las siguientes tinciones: hematoxilina-eosina-azul Alcián, tricrómico de Masson y rojo de picrosirius. En la técnica inmunohistoquímica de inmunoperoxidasa se utilizaron como anticuerpos primarios vimentina, PCNA y BMP. Los cartílagos claviculares son cartílagos hialinos cubiertos por una delgada capa de tejido mesenquimático. En su superficie se distinguen varias capas: superficial de tejido conectivo, proliferativa formada por células mesenquimáticas, madurativa con condrocitos hipertróficos y una zona de osificación con condrocitos en regresión y trabéculas óseas en formación. El anticuerpo anti PCNA mostró inmunotinción positiva en la capa proliferativa en todas las etapas estudiadas y el anticuerpo anti BMP se expresó intensamente en las células de las zonas de osificación. La técnica de picrosirius mostró colágeno tipo I en las capas superficiales. En los cartílagos claviculares la proliferación ocurre en el mesénquima de la capa proliferativa, en cambio, en los huesos largos la actividad mitótica ocurre en la zona de cartílago hiperplásico. En los cartílagos claviculares existe colágeno tipo I, a diferencia del cartílago de crecimiento epifisiario donde sólo existe colágeno tipo II. Los cartílagos secundarios de la clavícula presentan importantes diferencias morfológicas y funcionales en el crecimiento con los cartílagos primarios de los huesos largos.

MRI characteristics and transverse relaxation time measurements in normal growing cartilage / 华中科技大学学报（医学）（英德文版）

To determine the characteristics of magnetic resonance (MR) signals of normal growing cartilage and identify the difference in transverse relaxation times between physeal and epiphyseal cartilage in vivo. 24 distal femora of 12 two-week-old piglets were imaged on a 1.5 Tesla GE MR scanner. Comparison was made between signal intensity on MR images and the structure shown in corresponding histologic sections. T2 values were measured in eight piglets by means of multiecho spin-echo sequences. Our results showed that MR imaging delineated five regions between the secondary ossification center and the metaphysis, which histologically correspond to the zone of provisional calcification of the secondary ossification center, physis of the secondary ossification center, epiphyseal cartilage, physis and zone of provisional calcification. The T2 value in the physeal cartilage was much larger than that in the epiphyseal cartilage (P<0.05). It is concluded that MRI findings could differentiate the different regions of growing cartilage. T2 is longer in physeal than in epiphyseal cartilage, perhaps reflecting differences in water binding by proteoglycans.