The incidence of deep vein thrombosis and pulmonary embolism following cast immobilisation and early functional bracing of Tendo Achilles rupture without thromboprophylaxis.

Purpose: The routine use of thromboprophylaxis during cast immobilisation for lower leg trauma is controversial. The concern involves the perceived increased risk of deep vein thrombosis (DVT) and its sequelae following leg immobilisation. However, immobilisation is used for a spectrum of trauma and for varying duration. This heterogenicity in management is reflected in the current evidence and coupled with the risks of thromboprophylaxis; no clear consensus has been made.
Methods: In this retrospective study, we report the incidence of DVT and pulmonary embolism (PE) observed following cast immobilisation and early functional management of patients with Tendo Achilles rupture. Over 12 years, 945 consecutive patients (949 tendons) were treated without additional thromboprophylaxis.
Results: The incidence of DVT was 1.05 % and PE was 0.32 %. Females were significantly more likely to develop a DVT but not a PE. When compared to the incidence of DVT and PE observed in the general population, DVT rate was statistically significantly higher than that observed in the general population. There was no significant difference in PE rates. The number needed to treat to reduce the DVT incidence is 106. The number needed to treat to reduce the PE incidence is 475.
Conclusions: Although we can conclude that conservative treatment for Tendo Achilles does increase the incidence of symptomatic DVT from the general population, we feel that large randomised control trials are required to evaluate the efficacy, compliance and cost effectiveness of routine DVT thromboprophylaxis in the outpatient setting.