The study by Helwani et al. is one in a series that have demonstrated an outcome advantage of regional anesthesia for total hip arthroplasty. Using the rather complex statistical technique of propensity matching to eliminate bias, they showed improved outcomes at thirty days in a large database of U.S. hospitals. Improved outcomes have previously been found in both U.S. and British databases as well as in a single U.S. orthopaedic hospital. The current study showed a nonsignificant decrease in the mortality rate and a significant benefit of regional anesthesia in terms of respiratory and cardiovascular complications as well as prolonged length of hospital stay. None of this is surprising.

The most novel observation is the reduction in the rate of periprosthetic joint infection in the regional anesthesia group. A reduction in the overall rate of infectious complications has been recorded with regional anesthetic interventions in the past, but the complications have included urinary tract infection and minor wound infection, etc.. Periprosthetic joint infection is a major complication with a rate of about 1%, so large databases are needed to detect any differences. The halving of the rate of periprosthetic joint infection reported in this study is striking, and the reduction in socioeconomic burden is obvious. The mechanism for how regional anesthesia lowers the prevalence of periprosthetic joint infection is unknown but could be related to less immune modulation with regional anesthesia or the fact that aspirin, rather than powerful anticoagulants, are used with regional anesthesia. Blood loss and surgical site bleeding are significant factors in periprosthetic joint infection.