No abstract

A variety of biomaterials have been introduced as potential substrates for cartilage repair. One such candidate is chitosan, which shares some characteristics with glycosaminoglycan and hyaluronic acid present in articular cartilage. Depending on chitosan source and preparation procedure, variations into its properties can be attained. Thus, the aim of this article is to study and select the most adequate chitosan properties for in vivo osteochondral tissue regeneration. In this work, chitosan molecular weight, deacetylation degree, and calcium content are tested as material variable properties. According to these properties, porous scaffolds were prepared, implanted in rabbit knee osteochondral defects, and evaluated 3 months after surgery. Results show in vitro a considerable influence of the material molecular weight on the scaffold structure. In vivo, different tissue responses were observed depending on the implanted chitosan properties. Some samples showed no material degradation, multiple adverse tissue responses, and no bone/cartilage tissue formation. Other samples showed no adverse responses and bone and cartilage tissue regeneration. The chitosan with intact mineral content (17.9 wt %), lowest molecular weight (11.49 KDa), and lowest deacetylation degree (83%) shows a well structured subchondral bone and noticeable cartilaginous tissue regeneration, being it the best one of those tested for osteochondral defect regeneration.

Surgical treatment with osteosynthesis in type B post-operative fractures with a stable stem is recommended. Conservative treatment is sufficient in non-displaced type A post-operative fracture. Special attention should be paid to bone quality patients using non-cemented stems in primary surgery but especially in revision shoulder surgery.

Under simulated conditions of severe intraoperative contamination, the antibacterial suture reduced the number of positive cultures after surgery by 66.6%. Judging from the available clinical information, its use might contribute to reducing the number of infected implants by 25.8%. Human studies are needed to determine the clinical implications of these results.

Osteoarthritis (OA) is largely considered to be a non-inflammatory disease, although there is compelling evidence that subclinical inflammation is a common event, even in the absence of acute inflammatory flares. In this study we analyze, by means of CD5 and CD69 expression, the infiltration and early activation of CD5+cells, mostly lymphocytes, in both synovial membrane and synovial fluid from advanced OA patients and compare them with samples from patients with rheumatoid arthritis and healthy controls. The number of infiltrating CD5+ cells in both synovial membrane and synovial fluid from patients with advanced OA was significantly reduced as compared with rheumatoid arthritis patients. However, synovial membrane and synovial fluid CD5+ cells on OA exhibited a phenotype with evidence of recent activation comparable to that observed in RA.

No abstract

The aim of this work is to investigate the use of bone morphogenetic proteins (rhBMP-2, rhBMP-4) alone or in combination with cells delivered in a calcium alginate gel for the treatment of osteochondral defects. For this purpose, alginate gels were prepared mixing a 2% sodium alginate solution and a 200mM calcium chloride solution (1:1). Osteochondral defects were created (4mm wide, 5mm deep) in the internal femoral condyle of rabbit knee and gels were directly formed into the defects. 3 months after surgery samples were harvested, gross morphology was documented and histological appearance was evaluated. The performed histological observations revealed subchondral bone regeneration in rhBMP-2 samples and moderate hyaline cartilage regeneration in rhBMP-4 samples. Thus, results indicate that alginate gel may serve as an appropriate delivery vehicle for rhBMP-2, rhBMP-4 and stromal cells. With this carrier material, differential behaviour between the evaluated proteins was observed. rhBMP-2 shows better restoration of subchondral bone in contrast to the superior efficiency of rhBMP-4 for hyaline cartilage repair.

This first approach to the viral prevalence in MSCs of bone marrow in OA patients and healthy controls seems to show a very low risk of viral transmission or reactivation in a possible MSCs' transplantation.