Topical or IV tranexamic acid in knee replacement: no clear difference

Design

Systematic review and meta-analysis of randomised trials

Population

Patients having primary total knee arthroplasty, 11 trials

Primary outcome

Haemoglobin drop, blood loss, drainage and transfusion

Effect

Transfusion RR 0.64 (95% CI 0.34–1.21); haemoglobin drop SMD −0.29 (−0.75 to 0.16)

A systematic review and meta-analysis pooled 11 randomised trials comparing topical with intravenous tranexamic acid in primary total knee arthroplasty.

There was no significant difference in postoperative haemoglobin drop (9 trials, 815 patients), total blood loss, drain output or transfusion rate (10 trials, 914 patients; RR 0.64, 95% CI 0.34–1.21). Safety reporting was poor: only seven trials gave usable DVT data, and only one DVT was recorded, in an IV group.

The practical reading is that either route is reasonable for blood conservation, and the choice can rest on patient factors and local practice. Topical use may appeal where there is concern about systemic exposure, but these trials were too small and too thinly reported to say whether either route is safer.

• Either topical or IV tranexamic acid is a reasonable choice for blood conservation in primary knee replacement.
• Consider topical use where a clinician prefers to limit systemic exposure, recognising the safety data are thin.
• Do not read the absence of thrombotic events as proof of safety; few trials reported them.
• Continue to record haemoglobin drop and transfusion locally to audit whichever route you use.

Why it matters

It removes a reason to switch routes on efficacy grounds, leaving the choice to safety and convenience.

Don't overread it

Few trials reported thrombotic events, so this says little about comparative safety.

The statistics, in plain English

A transfusion risk ratio of 0.64 with an interval from 0.34 to 1.21 crosses 1, so the data are compatible with topical being better, the same or worse. A non-significant result in small trials is not proof the routes are equal.

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