Evidence now exists suggesting a neoplastic origin for pigmented villonodular synovitis, including a thorough description of the translocations involved. Arthroscopic excision for localized pigmented villonodular synovitis allows for both minimal recurrence and morbidity when compared with open excision; however, open excision still plays an important role in treating posterior compartment nodules. The optimal surgical treatment for diffuse pigmented villonodular synovitis is still a matter for debate, with combined anterior arthroscopic and open posterior excision being considered the preferred method. Radiation therapy has re-emerged as an additional treatment method for pigmented villonodular synovitis; however, the potential for serious toxicity makes it a questionable option, especially for such a benign condition. Small molecule and monoclonal antibody targeted therapies are being investigated as novel treatment methods for pigmented villonodular synovitis, with promising results.

No abstract

Biomimetic proteoglycan (BPG) diffusion into articular cartilage has the potential to restore the lost proteoglycan content in osteoarthritic cartilage given these molecules mimic the structure and properties of natural proteoglycans. We examined the diffusion characteristics of BPGs through cartilage with the use of a custom‐made in vitro cartilage diffusion model in both normal bovine and human osteoarthritic cartilage explants. BPGs were introduced into the cartilage through essentially one‐dimensional diffusion using osteochondral plugs. The molecular diffusion was shown to be size and concentration dependent. Diffusion profiles were found over different diffusion time intervals and the profiles were fit to a nonlinear Fickian diffusion model. Steady state 011012‐7diffusion coefficients for BPGs were found to be 4.01 and 3.53 μm2/s for 180 and 1600 kDa BPGs, respectfully, and these values are similar to other large molecule diffusion in cartilage. In both bovine and osteoarthritic human cartilage, BPGs were found localized around the chondrocytes. BPG localization was examined by labeling collagen type VI and soaking 5 μm thick sections of cartilage with BPG solutions demonstrating that the BPGs diffused into the cartilage and preferentially localized alongside collagen type VI in the pericellular matrix.

No abstract