Pilot study on the use of tourniquet: a risk factor for pulmonary thromboembolism after total knee arthroplasty?

The risk of pulmonary thromboembolism (PTE) after total knee arthroplasty (TKA) with tourniquet is still controversial. In this study, we determined whether plasma D-dimer could be used as a marker of PTE, and whether intraoperative use of tourniquet is a risk factor for symptomatic PTE after TKA. We divided 86 patients (12 males and 74 females) who underwent primary TKA into four groups based on (i) operation method (unilateral/bilateral) and (ii) use of pneumatic tourniquet during surgery (with/without). Plasma D-dimer values were measured preoperatively and on Day 1 postoperatively. “D1-value” was defined as the difference between postoperative and preoperative plasma D-dimer levels. We determined the cutoff level of “D1-value” for symptomatic PTE, monitored by O2 saturation (SAT) and lung scintigraphy. “D1-values” for patients with PTE symptoms were higher than those without symptoms (p<0.001). Furthermore, “D1-values” for TKA without tourniquet procedures were significantly lower than those with tourniquet both in unilateral (p=0.003) and bilateral groups (p=0.004). At a cutoff level of ≥8.6 μg/mL, the sensitivity, specificity, and positive and negative predictive values were 100%, 82.5%, 30.0% and 100% for symptomatic PTE, respectively. The results of our pilot study showed that elevated plasma “D1 value” is a sensitive marker for detection of PTE. Further studies will be needed, in order to evaluate the risk of tourniquet, and to reduce PTE after TKA.