BACKGROUND: The FDA approves novel, high-risk medical devices through the premarket approval (PMA) process based on clinical evidence supporting device safety and effectiveness. Devices subsequently may undergo postmarket modifications that are approved via one of several PMA supplement review tracks, usually without additional supporting clinical data. While orthopaedic devices cleared via the less rigorous 510(k) pathway have been studied previously, devices cleared through the PMA pathway and those receiving postmarket PMA supplements warrant further investigation. QUESTIONS/PURPOSES: We asked: What are (1) the types of original orthopaedic devices receiving FDA PMA approval, (2) the number and rate of postmarket device changes approved per device, (3) the types of PMA supplement review tracks used, (4) the types of device changes approved via the various review tracks, and (5) the number of device recalls and market withdrawals that have occurred for these devices? METHODS: All original PMA-approved orthopaedic devices between January 1982 and December 2014 were identified in the publically available FDA PMA database. The number of postmarket device changes approved, the PMA supplement review track used, the types of postmarket changes, and any FDA recalls for each device were assessed. RESULTS: Seventy original orthopaedic devices were approved via the FDA PMA pathway between 1982 and 2014. These devices included 34 peripheral joint implants or prostheses, 18 spinal implants or prostheses, and 18 other devices or materials. These devices underwent a median 6.5 postmarket changes during their lifespan or 1.0 changes per device-year (interquartile range, 0.4-1.9). The rate of new postmarket device changes approved per active device, increased from less than 0.5 device changes per year in 1983 to just fewer than three device changes per year in 2014, or an increase of 0.05 device changes per device per year in linear regression analysis (95% CI, 0.04-0.07). Among the 765 total postmarket changes, 172 (22%) altered device design or components. The majority of the design changes were reviewed via either the real-time review track (n = 98; 57%), intended for minor design changes, or the 180-day review track (n = 71; 41%), intended for major design changes. Finally, a total of 12 devices had FDA recalls at some point during their lifespan, two being for hip prostheses with high revision rates. CONCLUSIONS: Relatively few orthopaedic devices undergo the FDA PMA process before reaching the market. Orthopaedic surgeons should be aware that high-risk medical devices cleared via the FDA's PMA pathway do undergo considerable postmarket device modification after reaching the market, with potential for design "drift," ie, shifting away from the initially tested and approved device designs. CLINICAL RELEVANCE: As the ultimate end-users of these devices, orthopaedic surgeons should be aware that even among high-risk medical devices approved via the FDA's PMA pathway, considerable postmarket device modification occurs. Continued postmarket device monitoring will be essential to limit patient safety risks.