The effect of tourniquet use on postoperative opioid consumption after ankle fracture surgery - a retrospective cohort study.

Objectives: A pneumatic tourniquet is often used during ankle fracture surgery to reduce bleeding and enhance the visibility of the surgical field. Tourniquet use causes both mechanical and ischemic pain. The main purpose of this study was to evaluate the effect of tourniquet time on postoperative opioid consumption after ankle fracture surgery.

Methods: We retrospectively reviewed the files of 586 adult patients with surgically treated ankle fractures during the years 2014-2016. We evaluated post hoc the effect of tourniquet time on postoperative opioid consumption during the first 24 h after surgery. The patients were divided into quartiles by the tourniquet time (4-43 min; 44-58 min; 59-82 min; and ≥83 min). Multivariable linear regression analysis was used to evaluate the results.

Results: Tourniquets were used in 486 patients. The use of a tourniquet was associated with an increase in the total postoperative opioid consumption by 5.1 mg (95 % CI 1.6-8.5; p=0.004) during the first 24 postoperative hours. The tourniquet time over 83 min was associated with an increase in the mean postoperative oxycodone consumption by 5.4 mg (95 % CI 1.2 to 9.7; p=0.012) compared to patients with tourniquet time of 4-43 min.

Conclusions: The use of a tourniquet and prolonged tourniquet time were associated with higher postoperative opioid consumption during the 24 h postoperative follow-up after surgical ankle fracture fixation. The need for ethical approval and informed consent was waived by the Institutional Review Board of Northern Ostrobothnia Health District because of the retrospective nature of the study.