Results
knee arthroplasty
Thirty-one hospitals were randomized between April 15, 2019, and August 12, 2019. There were 21 public and 10 private hospitals included, and the median (range) number of hip and knee arthroplasty procedures at these hospitals performed in the year prior to study commencement was 580 (250 to 1617). All 31 hospitals were randomized, 16 to administer aspirin and 15 to administer enoxaparin. Between April 15, 2019, and December 18, 2020, 16 of 31 hospitals completed enrollment for their initially assigned therapy and crossed over to the alternate therapy prior to trial cessation (11 crossed over to aspirin and 5 crossed over to enoxaparin). The remaining 15 hospitals did not crossover prior to early cessation of the trial (