Materials and Methods
This study was a retrospective review of data collected prospectively by a
total joint replacement registry from April 1, 2001, to December 30, 2009.
During the study period, forty-five locations in six U.S. geographical regions
contributed cases to the total joint replacement registry, which was used to identify
the study sample. Details of the data collection and validation of the registry data
have been published previously. In brief, the registry collects information on
paper forms filled out at the time of the arthroplasty procedure and enhances this
information with data from the patients’ electronic health records and administration
claims available in this health-care system. Postoperative registry data are
collected via direct reporting by the surgeons as well as electronic screening of the
patients’ electronic health records with a validated algorithm.
Institutional review board approval was obtained before this study was
conducted