Long term outcomes of biomaterial-mediated repair of focal cartilage defects in a large animal model.

The repair of focal cartilage defects remains one of the foremost issues in the field of orthopaedics. Chondral defects may arise from a variety of joint pathologies and left untreated, will likely progress to osteoarthritis. Current repair techniques, such as microfracture, result in short-term clinical improvements but have poor long-term outcomes. Emerging scaffold-based repair strategies have reported superior outcomes compared to microfracture and motivate the development of new biomaterials for this purpose. In this study, unique composite implants consisting of a base porous reinforcing component (woven poly(ε-caprolactone)) infiltrated with 1 of 2 hydrogels (self-assembling peptide or thermo-gelling hyaluronan) or bone marrow aspirate were evaluated. The objective was to evaluate cartilage repair with composite scaffold treatment compared to the current standard of care (microfracture) in a translationally relevant large animal model, the Yucatan minipig. While many cartilage-repair studies have shown some success in vivo, most are short term and not clinically relevant. Informed by promising 6-week findings, a 12-month study was carried out and those results are presented here. To aid in comparisons across platforms, several structural and functionally relevant outcome measures were performed. Despite positive early findings, the long-term results indicated less than optimal structural and mechanical results with respect to cartilage repair, with all treatment groups performing worse than the standard of care. This study is important in that it brings much needed attention to the importance of performing translationally relevant long-term studies in an appropriate animal model when developing new clinical cartilage repair approaches.

Treatment of thrombotic thrombocytopenic purpura. Plasmapheresis, plasma transfusion, and vincristine.

In four patients with thrombotic thrombocytopenic purpura (TTP), the administration of plasma exchange and vincristine sulfate was associated with reversal of clinical and hematologic evidence of disease. Plasmapheresis with fresh frozen plasma replacement appears effective in acutely improving neurologic and hematologic abnormalities of patients with TTP and provides time for vincristine to become effective and induce lasting remissions. One patient with early relapse responded to a second short course of vincristine without other therapy. These data suggest that these treatment modalities should be considered as the initial treatment of TTP.