The second trial, done in North America,
randomized hip or knee replacement patients to tinzaparin at 75 IU/kg
once daily or warfarin to achieve an INR of 2.0-3.0. Both prophylactic
regimens were begun after surgery and continued at least until venography
was performed (an average of 9.4 days in both groups). This study was
also conducted in a double-blind fashion. Baseline characteristics were
similar in the two groups.