Statistical Methodology Sample size was determined based on an unpublished retrospective review of knee flexion in patients who had undergone TKA at the investigators institution having received a single injection ACB. From this review, a mean maximum knee flexion of 82 (SD = 2) degrees on the second day postoperatively was assumed. A 20% difference in knee flexion was considered to be clinically significant. To achieve an 80% power and to detect a 20% difference in knee flexion with a 2-sided Type I error rate of 0.05, the calculated minimum sample was 9 patients per group. To prevent loss of power due to early withdrawal of patients, incomplete data, non-functional adductor canal blocks and absence of statistical information on a comparable continuous infusion group, 20 patients in each were included group. General demographic data in both groups were compared using unpaired, two tailed t-tests for independent samples for continuous variables, and the Chi squared test (or Fisher's Exact test as appropriate) for categorical variables. Basic statistical tools were employed to describe the data: mean, median and standard deviation. Cumulative oxycodone consumption was compared between groups using analysis of covariance (ANCOVA) adjusted for age, gender and ASA status.