Effect of ankle versus thigh tourniquets on post-operative pain in foot and ankle surgery

Abstract

Background: Tourniquets are commonly used in elective extremity orthopaedic surgery to reduce blood loss, improve visualization in the surgical field, and to potentially reduce surgical time. There is a lack of consensus in existing guidelines regarding the optimal tourniquet pressure, placement site, and duration of use. There is a paucity of data on the relationship between the site of a tourniquet and postoperative pain in foot and ankle surgery.

Aim: To explore the relationship between tourniquet site and intensity of post-operative pain scores in patients undergoing elective foot and ankle surgery.

Methods: Retrospective analysis of prospectively collected data on 201 patients who underwent foot and ankle surgery in a single institution was undertaken. Intraoperative tourniquet duration, tourniquet pressure and site, and postoperative pain scores using Visual Analogue Score were collected in immediate recovery, at six hours and at 24 h post-op. Scatter plots were used to analyse the data and to assess for the statistical correlation between tourniquet pressure, duration, site, and pain scores using Pearson correlation coefficient.

Results: All patients who underwent foot and ankle surgery had tourniquet pressure of 250 mmHg for ankle tourniquet and 300 mmHg for thigh. There was no correlation between the site of the tourniquet and pain scores in recovery, at six hours and after 24 h. There was a weak correlation between tourniquet time and Visual Analogue Score immediately post-op (r = 0.14, P = 0.04) but not at six or 24 h post-operatively.

Conclusion: This study shows that there was no statistically significant correlation between tourniquet pressure, site and post-op pain in patients undergoing foot and ankle surgery. The choice of using a tourniquet is based on the surgeon's preference, with the goal of minimizing the duration of its application at the operative site.

Keywords: Lower limb surgery; Pain scores; Post-operative pain; Tourniquet pressure; Tourniquet site; Tourniquet time.

Figure 1

Scatter plots illustrating the correlation (r) between tourniquet time and the immediate post-operative, six-hour, and 24-h pain scores. A: Recovery pain score vs tourniquet time minutes; B: 6 h pain score vs tourniquet time minutes; C: 24 h pain score vs tourniquet time minutes. Note the weak correlation between tourniquet time and immediate post-operative pain scores with the absence of correlation to the six- and 24-h pain scores.

Figure 2

Whisker plot illustrating the absence of significant difference (P > 0.05) between immediate post-operative, six-hour, and 24-h pain scores as opposed to the tourniquet site (thigh vs ankle). A: Recovery pain score; B: 6 h pain score; C: 24 h pain score.