Chondrocostal grafting for lateral osteochondral injury of the metacarpal head.

Osteochondral injuries of the metacarpal head require anatomical restoration to prevent limitations in range of motion and osteoarthritis. Osteochondral bone grafting is a viable option, especially in younger patients. Central injuries allow for different types of grafting, but when the injured area is on the lateral portion of the metacarpal head, the graft must include both a cortical and a cartilaginous portion. We present here the pearls and pitfalls in the surgical technique of chondrocostal grating from the 6th rib and an example of its use within a case of comminuted fracture of the metacarpal head. This technique provides a graft with cortical bone that allows for a stable fixation, with few complications during its harvesting. The graft is viable in the long-term and shows similar magnetic resonance intensities in comparison to hand cartilage.

A cell-free approach with a supporting biomaterial in the form of dispersed microspheres induces hyaline cartilage formation in a rabbit knee model.

The objective of this study was to test a regenerative medicine strategy for the regeneration of articular cartilage. This approach combines microfracture of the subchondral bone with the implant at the site of the cartilage defect of a supporting biomaterial in the form of microspheres aimed at creating an adequate biomechanical environment for the differentiation of the mesenchymal stem cells that migrate from the bone marrow. The possible inflammatory response to these biomaterials was previously studied by means of the culture of RAW264.7 macrophages. The microspheres were implanted in a 3 mm-diameter defect in the trochlea of the femoral condyle of New Zealand rabbits, covering them with a poly(l-lactic acid) (PLLA) membrane manufactured by electrospinning. Experimental groups included a group where exclusively PLLA microspheres were implanted, another group where a mixture of 50/50 microspheres of PLLA (hydrophobic and rigid) and others of chitosan (a hydrogel) were used, and a third group used as a control where no material was used and only the membrane was covering the defect. The histological characteristics of the regenerated tissue have been evaluated 3 months after the operation. We found that during the regeneration process the microspheres, and the membrane covering them, are displaced by the neoformed tissue in the regeneration space toward the subchondral bone region, leaving room for the formation of a tissue with the characteristics of hyaline cartilage.