Osteoarthritis (OA) is a chronic and highly prevalent degenerative joint disease. Approximately 40 million Americans are currently affected, and this number is predicted to increase to 60 million within the next 20 years as a result of population aging and an increase in life expectancy (1,2). Current treatment is limited to pain management, and disease-modifying therapies are not available in the late phase of the disease process, at which point joint replacement surgery is often indicated. OA has been associated with age-related loss of the homeostatic balance between degradation and repair mechanisms. Cartilage cellularity in OA is reduced by chondrocyte death, and remaining chondrocytes are activated by cytokines and growth factors to a catabolic and abnormal differentiation that leads to degradation

Background:A previous cross-sectional study reported that pathogenic factors associated with Osgood-Schlatter disease (OSD) in adolescent athletes include increased quadriceps muscle tightness, lower leg malalignment, and development of apophysitis in the tibial tuberosity.Purpose:To confirm these pathogenic factors associated with OSD in a longitudinal study with regard to physical function and performance.Study Design:Cohort study; Level of evidence, 2.Methods:In this study, 37 boys (mean age, 10.2 ± 0.4 years) were recruited from 2 soccer teams at an elementary school. This cohort study was conducted over an observation period of 1 year, with measurements recorded at baseline, followed by screening for OSD every 6 months. Variables evaluated at baseline included physical function (morphometry, joint flexibility, and lower extremity alignment), presence of Sever disease, and kicking motion.Results:Pathogenic factors associated with OSD in the support leg of adolescent male soccer players included height, weight, body mass index, quadriceps femoris muscle tightness in the kicking and support legs, and gastrocnemius muscle tightness, soleus muscle tightness, and medial longitudinal arch in the support leg. Additional factors included a diagnosis of Sever disease and distance from the lateral malleolus of the support leg’s fibula to the center of gravity during kicking.Conclusion:The onset of OSD was found to be affected by many factors, including developmental stage, physical attributes, and pre-existing apophysitis. In particular, a diagnosis of Sever disease and backward shifting of the center of gravity during kicking increased the risk of the subsequent onset of OSD, suggesting that these factors are very important as a possible focus for interventions.

Recent studies demonstrate that histone deacetylase (HDAC) inhibitors therapeutically prevent cartilage degradation in osteoarthritis (OA). Matrix metalloproteinase-13 (MMP-13) plays an important role in the pathogenesis of this disease and in the present study we investigated the correlation between HDACs and MMP-13. We found that HDAC inhibitor trichostatin A (TSA) could suppress both IL-1 dependent and independent MMP-13 mRNA expression (real time PCR) in human knee chondrocytes. Comparing the expression of different HDACs in cartilage from OA patients and healthy donors, HDAC7 showed a significant elevation in cartilage from OA patients. These results were confirmed by immunohistochemistry. Knockdown of HDAC7 by siRNA in SW 1353 human chondrosarcoma cells strongly suppressed IL-1 dependent induction of MMP-13 gene expression. In conclusion, elevated HDAC7 expression in human OA may contribute to cartilage degradation via promoting MMP-13 gene expression and inhibition of HDACs by TSA or the selective inhibition of HDAC7 could be used therapeutically to stop OA progression.