Tranexamic acid decreases total blood loss after total hip arthroplasty (THA). Total blood loss is the sum of external bleeding and bleeding into tissues, i.e., haematomas. Haematomas may cause acute or even chronic postoperative pain.

Tranexamic acid decreases haematomas, thereby diminishing postoperative pain after THA.

In a retrospective matched case-control study, patients receiving tranexamic acid (15mg/kg, before the incision and again at skin closure) were compared to controls not given tranexamic acid. Matching was on sex, surgeon, and peri-operative analgesics (ketamine, ketoprofen, pregabalin, and nefopam). Standardised protocols were used for anaesthesia, analgesia, and blood sparing. Haematoma volume was computed as the difference between total blood loss (estimated from the erythrocyte counts on days –1 and +5) and measured external blood loss. Patients were monitored from D0 to D7 then interviewed by telephone on D30, D90, and D180. To detect a 30%-decrease in the morphine dose at H24 (criterion 1) and D7 (criterion 2) and a 20% decrease in haematoma volume on D5 (criterion 3), the required numbers of patients were 90, 90, and 77, respectively; therefore, 95 patients were included.

Tranexamic acid decreased haematoma volume by 30% (351±254mL versus 247±189mL erythrocytes, P=0.002), had no effect on morphine consumption at H24 (12±11mg versus 14±12mg, P=0.346), increased morphine consumption on D7 (26±24mg versus 35±36mg, P=0.029), and had no effect on long-term pain.

After THA, tranexamic acid decreases haematoma volume without improving analgesia.

3 (case-control study).