The present review article intends to direct attention to the technological advances made since 2009 in the area of genipin-crosslinked chitosan (GEN-chitosan) hydrogels. After a concise introduction on the well recognized characteristics of medical grade chitosan and food grade genipin, the properties of GEN-chitosan obtained with a safe, spontaneous and irreversible chemical reaction, and the quality assessment of the gels are reviewed. The antibacterial activity of GEN-chitosan has been well assessed in the treatment of gastric infections supported by Helicobacter pylori. Therapies based on chitosan alginate crosslinked with genipin include stem cell transplantation, and development of contraction free biomaterials suitable for cartilage engineering. Collagen, gelatin and other proteins have been associated to said hydrogels in view of the regeneration of the cartilage. Viability and proliferation of fibroblasts were impressively enhanced upon addition of poly-l-lysine. The modulation of the osteocytes has been achieved in various ways by applying advanced technologies such as 3D-plotting and electrospinning of biomimetic scaffolds, with optional addition of nano hydroxyapatite to the formulations. A wealth of biotechnological advances and know-how has permitted reaching outstanding results in crucial areas such as cranio-facial surgery, orthopedics and dentistry. It is mandatory to use scaffolds fully characterized in terms of porosity, pore size, swelling, wettability, compressive strength, and degree of acetylation, if the osteogenic differentiation of human mesenchymal stem cells is sought: in fact, the novel characteristics imparted by GEN-chitosan must be simultaneously of physico-chemical and cytological nature. Owing to their high standard, the scientific publications dated 2010–2015 have met the expectations of an interdisciplinary audience.

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Purpose The aim of this study was to investigate the presence of synovial mast cells (MCs) in hip and knee tissue from osteoarthritis (OA) patients and to correlate them with clinical and radiological data. Methods Synovial tissue was obtained during arthroplasty from 60 patients, 30 with knee OA and 30 with hip OA. Control synovial tissue was obtained from 30 patients without OA, 15 undergoing above-knee amputation and 15 receiving a hip replacement for fracture. Before surgery, the radiographic findings were graded according to the Kellgren-Lawrence system and clinical data including pain (VAS) and functional information (KOOS and HOOS) was collected. The tissue was stained with hematoxylin–eosin and toluidine blue for histochemistry and incubated with CD117 and CD31 antibodies for immunohistochemistry. MC and vessel number and synovitis score were determined in all samples. Results Mean MC number, synovitis score and vessel number were significantly higher in the OA samples (p < 0.05) than in control tissue. MC number correlated with the synovitis score and disease severity in both patient groups. Conclusions The prevalence of MCs in synovium from OA patients and their association with synovial inflammation and pain suggest a role for them in OA pathophysiology.

Full-thickness articular cartilage defects do not heal spontaneously. Several techniques have been developed to address this issue, but none resulted in the restitutio ad integrum of the articular cartilage. The most frequent sites of chondral lesion in the knee are medial femoral condyle and patella. The patellofemoral lesions are characterized by outcomes that are generally worse than those of tibiofemoral ones. To date, it has been well recognized the chondrogenic potential of rib perichondrium, and costal cartilage grafts have been extensively used in reconstructive surgery. Considering the need to find a gold standard technique to restore articular defect, we developed and here described a new technique to repair cartilage lesions of the knee using autologous costal cartilage graft with its perichondrium. This innovative surgical approach can be used to treat full thickness articular defects using autologous hyaline cartilage, making it possible to cover wide defects. This one step technique is low invasive, not technically demanding with minimal donor site morbidity and it has low costs. The long-term clinical efficacy of the method remains to be evaluated.

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