Osteoarthritis (OA) and degenerative disc disease (DDD) are common, chronic musculoskeletal disorders. Both diseases cause joint pain, loss of function, and decreased quality of life for the more than 27 million OA and 59 million DDD suffers in the US. According to a 2003 Medical Expenditure Panel Survey, arthritis such as OA costs the U.S. economy nearly $128 billion per year in medical care and indirect expenses including lost wages and productivity.