Patients undergoing bilateral hip or knee replacement;
Patients undergoing total hip or knee replacement who have been enrolled in this study for a prior hip or knee replacement;
Patients who are concurrently enrolled in another active interventional clinical trial testing a drug or intervention known or believed to interact with aspirin, warfarin, or rivaroxaban;
Patients who have a contraindication to two or more of the three study prophylaxis regimens;
Women who are pregnant or breastfeeding, as well as those of reproductive potential unless there is a negative urine pregnancy test on the day of surgery;
Patients on chronic (longer than the prior 6 months) anticoagulation other than with antiplatelet medications;
Patients with documented gastrointestinal, cerebral, or other hemorrhage within 3 months of the operation;
Patients with a known diagnosis of defective hemostasis and past history of clinical bleeding requiring transfusion and treatment;
Patients who have had an operative procedure involving the eye, ear, or central nervous system within one month;
Patients with severe uncontrolled hypertension with systolic BP > 220mmHg or diastolic BP > 120mmHg;
Patients with an absolute body weight of less than 41 kilograms (90.4 lbs) at baseline visit;
Vulnerable patient populations including prisoners and institutionalized individuals.

NCT02810704_exc_T1
Procedure
knee replacement
NCT02810704_exc_T2
Procedure
hip replacement
NCT02810704_exc_T3
Scope
hip or knee replacement
NCT02810704_exc_T4
Qualifier
bilateral
NCT02810704_exc_T5
Procedure
otal nee replacement
NCT02810704_exc_T6
Procedure
otal hip eplacement
NCT02810704_exc_T9
Condition
contraindication
NCT02810704_exc_T12
Drug
anticoagulation
NCT02810704_exc_T13
Negation
other than
NCT02810704_exc_T14
Drug
antiplatelet
NCT02810704_exc_T15
Temporal
longer than the prior 6 months
NCT02810704_exc_T16
Condition
intestinal, cere hage withi
NCT02810704_exc_T17
Condition
al, or o hage withi
NCT02810704_exc_T18
Condition
hemorrhage
NCT02810704_exc_T19
Temporal
within 3 months of the operation
NCT02810704_exc_T20
Reference_point
operation
NCT02810704_exc_T21
Scope
gastrointestinal, cerebral, or other hemorrhage
NCT02810704_exc_T22
Condition
hemostasis
NCT02810704_exc_T23
Qualifier
defective
NCT02810704_exc_T24
Condition
bleeding
NCT02810704_exc_T25
Procedure
transfusion
NCT02810704_exc_T26
Procedure
treatment
NCT02810704_exc_T27
Scope
transfusion and treatment
NCT02810704_exc_T28
Procedure
operative procedure
NCT02810704_exc_T29
Qualifier
eye
NCT02810704_exc_T30
Qualifier
ear
NCT02810704_exc_T31
Qualifier
central nervous system
NCT02810704_exc_T32
Temporal
within one month
NCT02810704_exc_T33
Scope
eye, ear, or central nervous system
NCT02810704_exc_T34
Condition
hypertension
NCT02810704_exc_T35
Qualifier
uncontrolled
NCT02810704_exc_T36
Qualifier
severe
NCT02810704_exc_T37
Measurement
systolic BP
NCT02810704_exc_T38
Value
> 220mmHg
NCT02810704_exc_T39
Measurement
diastolic BP
NCT02810704_exc_T40
Value
> 120mmHg
NCT02810704_exc_T41
Scope
systolic BP > 220mmHg or diastolic BP > 120mmHg
NCT02810704_exc_T42
Measurement
body weight
NCT02810704_exc_T44
Value
less than 41 kilograms
NCT02810704_exc_T45
Value
90.4 lbs
NCT02810704_exc_T43
Person
prisoners
NCT02810704_exc_T46
Visit
institutionalized