Articular Cartilage Changes in Maturing Athletes: New Targets for Joint Rejuvenation

CONTEXT: Articular cartilage has a unique functional architecture capable of providing a lifetime of pain-free joint motion. This tissue, however, undergoes substantial age-related physiologic, mechanical, biochemical, and functional changes that reduce its ability to overcome the effects of mechanical stress and injury. Many factors affect joint function in the maturing athlete—from chondrocyte survival and metabolism to structural composition and genetic/epigenetic factors governing cartilage and synovium. An evaluation of age-related changes for joint homeostasis and risk for osteoarthritis is important to the development of new strategies to rejuvenate aging joints. OBJECTIVE: This review summarizes the current literature on the biochemical, cellular, and physiologic changes occurring in aging articular cartilage. DATA SOURCES: PubMed (1969-2013) and published books in sports health, cartilage biology, and aging. STUDY SELECTION: Keywords included aging, athlete, articular cartilage, epigenetics, and functional performance with age. STUDY DESIGN: Systematic review. LEVEL OF EVIDENCE: Level 3. DATA EXTRACTION: To be included, research questions addressed the effect of age-related changes on performance, articular cartilage biology, molecular mechanism, and morphology. RESULTS: The mature athlete faces challenges in maintaining cartilage health and joint function due to age-related changes to articular cartilage biology, morphology, and physiology. These changes include chondrocyte loss and a decline in metabolic response, alterations to matrix and synovial tissue composition, and dysregulation of reparative responses. CONCLUSION: Although physical decline has been regarded as a normal part of aging, many individuals maintain overall fitness and enjoy targeted improvement to their athletic capacity throughout life. Healthy articular cartilage and joints are needed to maintain athletic performance and general activities. Genetic and potentially reversible epigenetic factors influence cartilage physiology and its response to mechanical and injurious stimuli. Improved understandings of the physical and molecular changes to articular cartilage with aging are important to develop successful strategies for joint rejuvenation.