Thromboprophylaxis in Lower Limb Immobilisation

The goal of this clinical trial is to find out the clinical and cost effectiveness of Thromboprophylaxis in participants who have been placed in a plaster cast or splint after injury. The main questions it aims to answer are: * whether giving tablets to people at high risks of clots after a leg injury is as good as injections (standard care) * whether giving any medication after a leg injury is better than standard care (advice only) for people at low risk of clots. Participants will be assessed to be high risk (TiLLI High) or low risk (TiLLI Low). People who are at high risk of clots will have either tablets or injections to reduce their risk. People at low risk will receive tablets, injections or no medication. Drug treatments will be provided for the duration of immobilisation or up to 42 days (whichever is earlier), in accordance with current NICE guidelines. The participants will be followed up for 90 days following randomisation.