If you fracture a tubular bone – e.g. your lower leg or forearm – through a fall or another accident, your doctor will most likely immobilise the limb by applying a cast. This, however, works only if the ends of the broken bones did not shift through the accident.
The affected area is then wrapped for a few weeks in a cast made of plastic rather than plaster, as used to be the case. Your doctor will ensure that you won’t be able to bend or turn the limb during the recovery phase, which is why the adjacent joint, in this case the wrist or ankle, is also included under the cast.
Your doctor will apply the cast firmly to the affected area to optimally stabilise it. What initially was a wet bandage then gradually hardens through a chemical reaction, resulting in a fully rigid cast. You can assume that the swelling comes from the fracture and won’t increase any more. If the affected area nevertheless continues to swell underneath the cast, the lack of space will cause a problem, usually in the form of pressure sores and poor circulation of the fingers or toes.
It’s often not so easy to determine whether the swelling has increased under the cast or if there are pressure sores. This is because the cast will feel unfamiliar at first and due to the painkillers you may have taken. To ensure that everything is alright, you should at first monitor the situation hourly by comparing the temperature of your fingers or toes with the temperature on the non-injured side. Furthermore, the skin colour of the injured side should be largely the same as on the healthy side. You should also not feel any tingling in the fingers or toes and be able to move them easily at any time.
If any of these issues apply or you notice problems with your blood circulation, motor skills and sensitivity, you need to remove the cast immediately so that the blood supply to the area can be restored as quickly as possible.