The Impact of Study Period on Perioperative Outcomes Following Hip Arthroplasty

We hypothesized that the time period studied would have a greater impact on perioperative outcomes than the hip arthroplasty procedure performed, demonstrating concerns with studies comparing new techniques to “historical” controls. One hundred total hip arthroplasty (THA) and 100 surface replacement arthroplasty (SRA) patients performed between 2004 and 2010 (“historical” period) were matched and compared to 50 THA and 50 SRA patients performed between 2010 and 2012 (“recent” period). Time to discharge was significantly improved for both the THA and SRA groups in the recent versus historical period by 16 hours (P < 0.001). At both periods, THA patients were discharged earlier by 9 hours versus SRAs (P < 0.0001). Study time frame had a greater impact than the operative procedure on perioperative metrics.