Ultrastructural aspects of chondrodystrophia calcificans congenita (syndrome of Conradi-Hünermann)

Summary An ultrastructural study of chondrodystrophia calcificans congenita is reported. Foci of initial calcification of cartilage are characterized by coexistence of three different types of crystals, probably due to abnormal proteoglycan composition of cartilage matrix. The calcification process in chondrodystrophia calcificans congenita is apparently not related to matrix vesicles as it is in normal cartilage.     

Morphomechanics of the humero-ulnar joint: II. Concave incongruity determines the distribution of load and subchondral mineralization

Background: A deeper joint socket (concave incongruity) is found at most angles of flexion of the humero-ulnar joint and maintained over a wide range of physiological loading. It is, however, unclear how far this incongruity affects the distribution of load and subchondral mineralization of this joint as compared with a congruous configuration. Methods: Two nonlinear, axisymmetrical finite element models with two cartilage layers were constructed, one congruous and one incongruous, with a joint space of realistic magnitude. The distribution of subchondral mineralization was determined by computed tomography osteoabsorptiometry in the same six specimens that were investigated in the first part of the study, and compared with the biomechanical data obtained there and the predictions of the models. Results: In the congruous case, the center of the socket is highly loaded, whereas the periphery does not experience mechanical stimulation. A central bone density maximum is predicted. With concave incongruity the position of the contact areas shifts from the joint margin towards the center as the load increases, and the peak stresses are considerably lower. A bicentric ventro-dorsal distribution pattern of subchondral mineralization is predicted, and this is actually found in the six specimens. Conclusions: Concave incongruity is shown to determine load transmission and subchondral mineralization of the humero-ulnar joint. It is suggested that this shape leads to a more even distribution of stress, provides intermittent stimulation of the cartilaginous tissue, and has beneficial effects on the metabolism, nutrition, and lubrication of the articular cartilage during cyclic loading. © 1995 Wiley-Liss, Inc.     

The Effects of Extracellular Matrix on Tissue Engineering Construction of Cartilage in Vitro

In the study of bone and cartilage diseases in our laboratory, chondrocyte stereo-differentiation mod-el was cultured into cartilage tissue. The cultured cartilage tissue was closely similar to natural tissue inboth histological condition and biochemical metabolism. The model mimicked the chondrocyte differenti-ation and metabolism in vivo completely〔1〕. We studied some essential extracellular matrices, includingcollagen, proteoglycan(PG) and hyaluronic acid(HA) on the construction of grow…     

Biological resurfacing of the knee: a review of surgical management

Lesions of the articular surfaces of the knee have been managed by various techniques over the last 50 years. Surgical management has involved: excising the damaged area, refashioning the underlying bone to produce a fibrous response, and introducing allograft, autograft and synthetic materials to encourage a repair matrix. The techniques and their pitfalls are reviewed and discussed, and suggestions made as to the direction of future studies for the repair of osteochondral lesions in the painful knee.     

Magnetic resonance imaging of femoral head development in roentgenographically normal patients

Magnetic resonance images (MRI) of 22 patients with roentgenographically normal hips were reviewed retrospectively and the findings categorized according to age. With increasing maturity, the MR intensity of the femoral heads on spin echo images increased, as marrow fat became a dominant tissue in the head. The femoral head pattern was relatively inhomogeneous, with a broad band of diminished intensity extending in a posteromedial to anterolateral direction, corresponding to the pattern of trabecular bone. The femoral capital epiphyses were visible in younger patients as structures of bright intensity which remained evident through early adulthood. The articular cartilage of the hip joint was noted as a distinctive halo around the femoral head. An understanding of the MR pattern of the normal hip will aid in the early recognition of pathologic conditions, such as osteonecrosis.     

The bilateral conchal cartilage graft: A new technique in augmentation rhinoplasty

The most common procedures to reconstruct a severe saddle-nose deformity are autogenous costal cartilage, iliac bone grafting, or Silastic implants. Each of them has its specific disadvantages. As an alternative solution, an autogenous bilateral conchal graft in sand-wich technique is described. A 3-layer graft for the dorsum and a 2-layer graft to support the depressed columellar-tip area grants a more natural and elastic reconstruction of the nasal framework. The conchal grafts are taken by an incision made on the preauricular surface of the ear. How to plane the curved grafts by meticulous cross-hatching and to immobilize them in the recipient area by transcutaneous suturing is demonstrated.Presented at the VIII International Congress of Plastic and Reconstructive Surgery, Montreal, Canada, June, 1983     

自体骨膜游离移植修复关节软骨缺损进展

探讨自体骨膜游离移植修复关节软骨缺损的研究进展。从骨膜的解剖生理功能和骨膜再生软骨能力两方面进行分析,并阐述了关节内营养环境、关节活动、骨膜生发层不同朝向、年龄及手术技巧等因素对移植修复的影响。同时总结了该方法的临床应用状况、效果及存在的问题。实验及临床的研究证明自体骨膜游离移植是修复关节软骨缺损的重要手段,局部环境因素影响骨膜成软骨。