 Major orthopedic procedures, including total joint replacement and spine surgeries, are among the most common procedures in the population. Learning about how often these surgeries are performed can give indications of whether the treatment of arthritis and other musculoskeletal conditions has been improving over time. Learning about the complications associated with these surgeries can give indications about ways to alter the care of patients before and after surgeries that may decrease the risk of complications and improve patient outcomes. We will analyze Medicare and Medicaid data from 1999 to 2015 to examine a series of questions, including whether the use of joint replacement surgery has changed over time among patients with rheumatoid arthritis and ankylosing spondylitis, to see if rheumatoid arthritis medications are associated with some types of surgical complications, to see if anticoagulation medication after joint replacement is associated with the risk of complications, to see if regional differences in surgery rates can be explained by differences in patient characteristics, and to determine the surgical treatment for hip fractures that is associated with the fewest long-term complications. From the Framingham Heart Study Cohort, we will study the changes in the incidence of hip fractures and the risk factors for osteoporosis over time. 