Tranexamic acid reduces intraoperative occult blood loss and tourniquet time in obese knee osteoarthritis patients undergoing total knee arthroplasty: a prospective cohort study.

Purpose: Obesity can result in increased blood loss, which is correlated with poor prognosis in total knee arthroplasty (TKA). Clinical application of tranexamic acid is effective in reducing blood loss in TKA. However, most previous studies focused on the effect of tranexamic acid in the whole population, neglecting patients with specific health conditions, such as obesity. We hypothesized that tranexamic acid would reduce blood loss to a greater extent in obese patients than in those of normal weight.

Patients and methods: A total of 304 patients with knee osteoarthritis treated with TKA from October 2013 to March 2015 were separated into tranexamic, non-tranexamic, obese, and non-obese groups. The demographic characteristics, surgical indices, and hematological indices were all recorded. We first investigated the ability of intravenous tranexamic acid to reduce intraoperative blood loss in knee osteoarthritis patients undergoing unilateral TKA. Second, we performed subgroup analysis to compare the effects of tranexamic acid between obese and non-obese patients separately.

Results: Of the 304 patients, 146 (52.0%) received tranexamic acid and 130 (42.8%) were obese. In the analysis of the whole group, both the actual and occult blood loss volume were lower in the tranexamic acid group (both P < 0.05). Tourniquet time was shorter in the tranexamic acid group ( P < 0.05). In subgroup analysis, tranexamic acid was shown to reduce theoretical and actual blood loss in both the obese and non-obese groups ( P < 0.05). Tranexamic acid reduced occult blood loss and tourniquet time in the obese group ( P < 0.05), while no such effects were observed in the non-obese group ( P > 0.05).

Conclusion: Tranexamic acid can reduce occult blood loss and tourniquet time in obese patients to a greater extent than in patients of normal weight. Therefore, obese knee osteoarthritis patients undergoing TKA can benefit more from tranexamic acid.