Comparison of low and high dose aspirin in prevention of venous thromboembolism after hip and knee arthroplasty

Comparison of low and high dose aspirin in prevention of venous thromboembolism after arthroplasty of hip and knee joints

This is a double-blind, randomized clinical trial study, with parallel groups and without control group. 540 patients who underwent hip and knee arthroplasty in Sina, Shariati and Imam Khomeini hospitals are divided into two groups. In this study, venous thrombosis is monitored within 6 weeks . Suspected cases of venous thrombosis are diagnosed by color Doppler ultrasound and cases suspected of pulmonary embolism are scanned by perfusion or CT pulmonary angiography.

In this study, in hospitals including Sina Hospital, Shariati Hospital and Imam Khomeini Hospital, patients who underwent hip and knee arthroplasty are divided into two groups. In this study, they receive the mentioned drugs within 6 weeks after the operation and during this clinical signs of Venous thrombosis is observed for 6 weeks .Sampling is done by available method. The study is double-blind and in terms of medication received, the surgeon and the patient do not know what dose of medication to receive for the patient's prophylaxis.

patients candidate for hip and knee arthroplasty liver dysfunction any contraindication for anticoagulant therapy indication for enoxaparin therapy active cancer

Patients who underwent hip and knee arthroplasty ,receive 80 mg aspirin twice daily in one group and 325 mg aspirin twice daily in another group after surgery. thrombosis will be monitored in 6 weeks.

deep vein thrombosis, pulmonary embolism

In this study, the law of random allocation based on computer program randomization is used to randomize the treatment groups, so that 540 samples are randomly assigned to group A (aspirin 80) and B (aspirin 320) ( Random allocation table). In this way, patients attended to the hospital for surgery receive a single code and based on that code, one of the two treatment groups is considered for them. Also, in order to blind the study, envelopes containing cards with numbers 1 to 540 (number of study sample volumes) are prepared and the lids of the letter envelopes are glued and placed in a box. At the beginning of the registration, according to the order of entry of eligible participants to the study , one of the envelopes opened and its assigned group revealed based on the number registered on the participant card. It should be noted that these envelopes are only for one person and that number cant any longer be taken. Example: For the first patient, one of the envelopes in the box is selected. It is seen after opening box number 25. After referring to the random allocation table, it is observed that patient 25 should receive drug B, which is defined as aspirin 320. In order to ensure the status of the allocations and non-repetition, after selecting the groups and knowing the status of the treatment, the information will be inserted in a table (like the table below) .

The study is double-blind ,means both surgeon (specialist assistant) and patient don't know the dose of prophylactic medicine .After surgery doctor will be informed .Hospitalization time, surgeon, pain control protocol ,anesthesia technique and volume of intraoperative lavage are similar in both groups and postoperative rehabilitation is the same ..