Dupuytren's contracture (also called dupuytren's disease) is when the skin in your palm thickens and causes a nodule which can lead to a finger contracting down.
It commonly affects the ring and little finger, but you can get it in any of your fingers and also your thumb.
Firstly, your hand consultant will check to see if there is an injury to the finger or tendon which could be a reason why the finger won't straighten but the key thing to show dupuytren’s contracture is that it is very difficult to straighten the finger.
Generally, if you cannot put your hand flat on a surface and it is interfering with your general hand function, then treatment may be needed.