OBJECTIVES: The objective of this analysis was to highlight the differences in gender pain management after a total knee arthroplasty in the United States. METHODS: We identified 103,600 TKA procedures from the Thomson Reuters MarketScan® Commercial and Medicare Claim databases from January 1, 2003 through June 30, 2009. For these procedures, we analyzed 873,237 pharmaceutical claims for muscle relaxants and analgesics/antipyretics for the 12-month postoperative period.  The mean direct costs were calculated for each calendar year for gender cohorts and not inflation-adjusted. Wilcoxon-Mann-Whitney tests were run for each year to determine statistical significance among the gender cohorts. RESULTS: During the analysis period, we found statistically significant differences in pharmaceutical pain management spending between male and female cohorts.  The female cohort spending averaged $464 per patient for the 12-month postoperative period compared to $364 for the male cohort. This represents a 27% difference. During this same period, the average number of pharmaceutical pain management claims per TKA decreased for all cohorts but these averages exhibited convergence in 2008 as spending by males increased slightly. CONCLUSIONS: Published studies have failed to agree on the correlation between gender and postoperative pain. A recent postoperative pain study concluded that “gender was not found to be a consistent predictor as traditionally believed1.”  However, our retrospective analysis of actual claim data provides a statistically significant correlation between female gender and increased consumption of postoperative muscle relaxants and analgesics for total knee arthroplasty procedures.  These data may help surgeons provide appropriate postoperative care for their TKA patients. 1Ip, Hui Yun Vivian, Et. al, Predictors of Postoperative Pain and Analgesic Consumption: A Qualitative Systematic Review, Anesthesiology, September 2009:11(3)657-677. MarketScan® is a trademark of Thomson Reuters (Healthcare) Inc.