Even with current treatments of acute joint injuries, more than 40% of people who suffer significant ligament or meniscus tears, or articular surface injuries, will develop osteoarthritis (OA). Correspondingly, 12% or more of all patients with lower extremity OA have a history of joint injury. Recent research suggests that acute joint damage that occurs at the time of an injury initiates a sequence of events that can lead to progressive articular surface damage. New molecular interventions, combined with evolving surgical methods, aim to minimize or prevent progressive tissue damage triggered by joint injury. Seizing the potential for progress in the treatment of joint injuries to forestall OA will depend on advances in (1) quantitative methods of assessing the injury severity, including both structural damage and biologic responses, (2) understanding of the pathogenesis of post-traumatic OA, taking into account potential interactions among the different tissues and the role of post-traumatic incongruity and instability, and (3) application of engineering and molecular research to develop new methods of treating injured joints. This paper highlights recent advances in understanding of the structural damage and the acute biological response following joint injury, and it identifies important directions for future research. ß

Styrene oligomers (Mn, 2500–3000 g/mol) with low polydispersity index and containing peroxidic groups within their structure were synthesized using a novel trifunctional cyclic radical initiator, diethylketone triperoxide (DEKTP), through nitroxide‐mediated radical polymerization (NMRP), using OH‐TEMPO. During the synthesis of the polystyrene (PS) oligomers, camphorsulfonic acid (CSA) was used to inhibit the thermal autoinitiation of styrene at the evaluated temperatures (T = 120–130°C). The polymerization rate, which can be related to the slope of the plot of monomer conversion with reaction time, was monitored as a function of OH‐TEMPO, DEKTP, and CSA concentrations. The experimental results showed that all the synthesized polymers presented narrow molecular weight distributions, and the monomer conversion and the molecular weight of the polymers increased as a function of reaction time. Under the experimental conditions, T = 130°C, [DEKTP] = 10 mM, and [DEKTP]/[OH‐TEMPO] = 6.5, PS oligomers containing unreacted OO sites in their inner structure were obtained. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Osteoarthritis (OA), the syndrome of joint pain and dysfunction caused by joint degeneration, affects more people than any other joint disease. In most instances joint degeneration develops in the absence of an identifiable cause, but increasing age, excessive joint loading, and joint abnormalities and insults increase the risk of OA. Articular surface contact stress that causes tissue damage and compromises that ability of chondrocytes to maintain and restore the tissue has an important role in the development of joint degeneration Current methods of attempting to restore an articular surface in osteoarthritic joints include penetrating subchondral bone, altering joint loading, osteotomies and insertion of soft tissue grafts. Dramatic advances in the prevention and treatment of OA are likely to stem from better understanding of the role of mechanical forces in the initiation and progression of joint degeneration.

No abstract

No abstract