TTi designed a clinical study designed to evaluate patient outcomes resulting from use of Forced Air Warming (FAW) technology during hip and knee replacement surgeries, with a primary outcome of surgical site infections (particularly deep joint infections).  The study design involved a facility-matched case-comparator, identifying hospital sites by the type of patient warming technology they use and examining infection rates in facilities that use FAW versus those that do not.  A secondary study design involved identifying facilities that have switched technologies and comparing infection rates pre- and post-switch.