Development of the Plymouth VTE Risk Score for patients treated with lower limb immobilisation in a cast or boot

There is approximately a 2% risk of clinically significant VTE following temporary lower limb immobilisation after injury with an ankle immobilising plaster cast or boot. There is evidence that thromboprophylaxis for lower limb immobilised patients reduces the risk of VTE by approximately 50% but there is no international consensus as to which patients should receive thromboprophylaxis. The Plymouth VTE Risk Score was developed to identify patients at particular risk of VTE, in order to offer chemical prophylaxis to reduce their VTE risk. The score showed high completion rates, reliability and consistency. Using the Plymouth VTE Risk Score Version 3 (2014), we found an incidence of clinical VTE of 0.36% with 37.6% of patients being advised to have thromboprophylaxis. This is a lower VTE incidence than in most other studies of this patient group, which is of the order of 2 to 3%. The optimal RAM to use in clinical practice is yet to be defined, further clinical research is needed to accurately stratify patient risk and to define optimal risk treatment levels. We suggest research should focus on comparative clinical studies of risk assessment models.