Evaluation of the Accuracy of Output Values of Torque Wrenches in Clinical Settings

Aim: The aim of this in vitro study was to determine and compare the accuracy of different types of mechanical torque limiting devices currently used in clinical settings. Materials and Methods: A total of 30 torque wrenches including both friction-style (n=17) and springstyle (n=13) instruments were evaluated in this study. A calibrated digital torque meter (Lutron TQ-8800; Lutron Electronic Enterprise Co., Ltd.; Taiwan) was used to measure the output torque values of the torque wrenches. Measurements were repeated 10 times for each wrench and reported in Ncm. The Shapiro-Wilk test was performed for mean torque measurment values followed by an independent t-test and the percentages of absolute deviation from target torque values were calculated. The results were evaluated at a 95% confidence interval with significance at p<0.05. Results: The mean torque measurement values of friction-style devices showed a statistically significant difference from target torque values (p<0.05), while the mean torque measurement values of spring-style devices did not differ significantly from target values (p>0.05). While the percentage deviation values ranged between 7.64 and 11.76 for friction-style devices, they were 1.79- 5.12 for spring-style devices. Conclusion: The accuracy of spring-type torque wrenches is better than that of friction-type torque wrenches, and the calibration of all wrenches should routinely be performed at the target torque value specified by the manufacturer to ensure optimum healthcare services.